Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ACAD SCIENCES  

A complex consisting of evolutionarily conserved FD, FLOWERING LOCUS T (FT) proteins is a regulator of floral transition. Intriguingly, FT orthologs are also implicated in developmental transitions distinct from flowering, such as photoperiodic control of bulbing in onions, potato tuberization, and growth cessation in trees. However, whether an FT-FD complex participates in these transitions and, if so, its mode of action, are unknown. We identified two closely related FD homologs, FD-like 1 (FDL1) and FD-like 2 (FDL2), in the model tree hybrid aspen. Using gain of function and RNAi-suppressed FDL1 and FDL2 transgenic plants, we show that FDL1 and FDL2 have distinct functions and a complex consisting of FT and FDL1 mediates in photoperiodic control of seasonal growth. The downstream target of the FT-FD complex in photoperiodic control of growth is Like AP1 (LAP1), a tree ortholog of the floral meristem identity gene APETALA1. Intriguingly, FDL1 also participates in the transcriptional control of adaptive response and bud maturation pathways, independent of its interaction with FT, presumably via interaction with ABSCISIC ACID INSENSITIVE 3 (ABI3) transcription factor, a component of abscisic acid (ABA) signaling. Our data reveal that in contrast to its primary role in flowering, FD has dual roles in the photoperiodic control of seasonal growth and stress tolerance in trees. Thus, the functions of FT and FD have diversified during evolution, and FD homologs have acquired roles that are independent of their interaction with FT.

DOI： 10.1073/pnas.1423440112

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Plant and Cell Physiology  

Plants undergo a series of developmental phases throughout their life-cycle, each characterized by specific processes. Three critical features distinguish these phases: the arrangement of primordia (phyllotaxis), the timing of their differentiation (plastochron) and the characteristics of the lateral organs and axillary meristems. Identifying the unique molecular features of each phase, determining the molecular triggers that cause transitions and understanding the molecular mechanisms underlying these transitions are keys to gleaning a complete understanding of plant development. During the vegetative phase, the shoot apical meristem (SAM) facilitates continuous leaf and stem formation, with leaf development as the hallmark. The transition to the reproductive phase induces significant changes in these processes, driven mainly by the protein FT (FLOWERING LOCUS T) in Arabidopsis and proteins encoded by FT orthologs, which are specified as ‘florigen’. These proteins are synthesized in leaves and transported to the SAM, and act as the primary flowering signal, although its impact varies among species. Within the SAM, florigen integrates with other signals, culminating in developmental changes. This review explores the central question of how florigen induces developmental phase transition in the SAM. Future research may combine phase transition studies, potentially revealing the florigen-induced developmental phase transition in the SAM.

DOI： 10.1093/pcp/pcae001

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Structure-based high-throughput screening of chemical compounds that target protein-protein interactions (PPI) is a promising technology for gaining insight into how plant development is regulated, leading to many potential agricultural applications. At present, there are no examples of using high-throughput screening to identify chemicals that target plant transcriptional complexes, some of which are responsible for regulating multiple physiological functions. Florigen, a protein encoded by FLOWERING LOCUS T (FT), was initially identified as molecule that promotes flowering and has since been shown to regulate flowering and other developmental phenomena such as tuber formation in potato. FT functions as a component of the florigen activation complex (FAC) with a scaffold protein 14-3-3 and FD, a bZIP transcription factor that activates downstream gene expression. Although 14-3-3 is an important component of FAC, there are little functional analysis of the 14-3-3 itself. Here, we report the results of a high-throughput in vitro fluorescence resonance energy transfer (FRET) screening of chemical libraries that enabled us to identify small molecules capable of inhibiting FAC formation. These molecules abrogate the in vitro interaction between 14-3-3 and OsFD1 peptide, a rice FD, by directly binding to 14-3-3. Treatment with S4, a specific hit molecule, strongly inhibited FAC activity and flowering in duckweed, tuber formation in potato and branching in rice in a dose-dependent manner. Our results demonstrate that the high-throughput screening approach based on three-dimensional structure of PPI is possible in plants. In this study, we have proposed good candidate compounds for future modification to obtain inhibitors of florigen-dependent processes through inhibition of FAC formation.

DOI： 10.1111/tpj.16008

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In potato (Solanum tuberosum L.), 14-3-3 protein forms a protein complex with the FLOWERING LOCUS T (FT)-like protein StSP6A and the FD-like protein StFDL1 to activate potato tuber formation. Eleven 14-3-3 isoforms were reported in potato, designated as St14a-k. In this study, the crystal structure of the free form of St14f was determined at 2.5 Å resolution. Three chains were included in the asymmetric unit of the St14f free form crystal, and the structural deviation among the three chain structures was found on the C-terminal helix H and I. The St14f free form structure in solution was also investigated by nuclear magnetic resonance (NMR) residual dipolar coupling analysis, and the chain B in the crystal structure was consistent with NMR data. Compared to other crystal structures, St14f helix I exhibited a different conformation with larger B-factor values. Larger B-factor values on helix I were also found in the 14-3-3 free form structure with higher solvent contents. The mutation in St14f Helix I stabilized the complex with StFDL1. These data clearly showed that the flexibility of helix I of 14-3-3 protein plays an important role in the recognition of target protein.

DOI： 10.1038/s41598-022-15505-y

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Lateral roots (LRs) occupy a large part of the root system and play a central role in plant water and nutrient uptake. Monocot plants, such as rice, produce two types of LRs: the S-type (short and thin) and the L-type (long, thick, and capable of further branching). Because of the ability to produce higher-order branches, the L-type LR formation contributes to efficient root system expansion. Auxin plays a major role in regulating the root system development, but its involvement in developing different types of LRs is largely unknown. Here, we show that auxin distribution is involved in regulating LR diameter. Dynamin-related protein (DRP) genes were isolated as causative genes of the mutants with increased L-type LR number and diameter than wild-type (WT). In the drp mutants, reduced endocytic activity was detected in rice protoplast and LRs with a decreased OsPIN1b-GFP endocytosis in the protoplast. Analysis of auxin distribution using auxin-responsive promoter DR5 revealed the upregulated auxin signaling in L-type LR primordia (LRP) of the WT and the mutants. The application of polar auxin transport inhibitors enhanced the effect of exogenous auxin to increase LR diameter with upregulated auxin signaling in the basal part of LRP. Inducible repression of auxin signaling in the mOsIAA3-GR system suppressed the increase in LR diameter after root tip excision, suggesting a positive role of auxin signaling in LR diameter increase. A positive regulator of LR diameter, OsWOX10, was auxin-inducible and upregulated in the drp mutants more than the WT, and revealed as a potential target of ARF transcriptional activator. Therefore, auxin signaling upregulation in LRP, especially at the basal part, induces OsWOX10 expression, increasing LR diameter.

DOI： 10.3389/fpls.2022.834378

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Tissue clearing methods are increasingly essential for the microscopic observation of internal tissues of thick biological organs. We previously developed TOMEI, a clearing method for plant tissues; however, it could not entirely remove chlorophylls nor reduce the fluorescent signal of fluorescent proteins. Here, we developed an improved TOMEI method (iTOMEI) to overcome these limitations. First, a caprylyl sulfobetaine was determined to efficiently remove chlorophylls from Arabidopsis thaliana seedlings without GFP quenching. Next, a weak alkaline solution restored GFP fluorescence, which was mainly lost during fixation, and an iohexol solution with a high refractive index increased sample transparency. These procedures were integrated to form iTOMEI. iTOMEI enables the detection of much brighter fluorescence than previous methods in tissues of A. thaliana, Oryza sativa, and Marchantia polymorpha. Moreover, a mouse brain was also efficiently cleared by the iTOMEI-Brain method within 48 h, and strong fluorescent signals were detected in the cleared brain.

DOI： 10.1038/s42003-021-02955-9

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

The three-dimensional (3D) arrangement of cells in tissues provides an anatomical basis for analyzing physiological and biochemical aspects of plant and animal cellular development and function. In this study, we established a protocol for tissue clearing and 3D imaging in rice. Our protocol is based on three improvements: clearing with iTOMEI (clearing solution suitable for plants), developing microscopic conditions in which the Z step is optimized for 3D reconstruction, and optimizing cell-wall staining. Our protocol successfully 3D imaged rice shoot apical meristems, florets, and root apical meristems at cellular resolution throughout whole tissues. Using fluorescent reporters of auxin signaling in rice root tips, we also revealed the 3D distribution of auxin signaling events that are activated in the columella, quiescent center, and multiple rows of cells in the stele of the root apical meristem. Examination of cells with higher levels of auxin signaling revealed that only the central row of cells was connected to the quiescent center. Our method provides opportunities to observe the 3D arrangement of cells in rice tissues.

DOI： 10.3390/ijms23010040

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Reactive oxygen species (ROS) play essential roles in plant development and environmental stress responses. In this study, ROS dynamics, the glutathione redox status, the expression and subcellular localization of glutathione peroxidases (GPXs), and the effects of inhibitors of ROS-mediated metabolism were investigated along with fertilization and early zygotic embryogenesis in rice (Oryza sativa). Zygotes and early embryos exhibited developmental arrest upon inhibition of ROS production. Egg cells accumulated high ROS levels, and, after fertilization, intracellular ROS levels progressively declined in zygotes in which de novo expression of GPX1 and 3 was observed through upregulation of the genes. In addition to inhibition of GPX activity, depletion of glutathione impeded early embryonic development and led to failure of the zygote to appropriately decrease H2 O2 levels. Moreover, through monitoring of the glutathione redox status, the developing zygotes exhibited a progressive glutathione oxidation, which became extremely delayed under inhibited GPX activity. Our results provide insights into the importance of ROS dynamics, GPX antioxidant activity, and glutathione redox metabolism during zygotic/embryonic development.

DOI： 10.1111/tpj.15497

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Duckweeds (Araceae: Lemnoideae) are aquatic monocotyledonous plants that are characterized by their small size, rapid growth, and wide distribution. Developmental processes regulating the formation of their small leaf-like structures, called fronds, and tiny flowers are not well characterized. In many plant species, flowering is promoted by the florigen activation complex, whose major components are florigen FLOWERING LOCUS T (FT) protein and transcription factor FD protein. How this complex is regulated at the molecular level during duckweed flowering is also not well understood. In this study, we characterized the course of developmental changes during frond development and flower formation in Lemna aequinoctialis Nd, a short-day plant. Detailed observations of frond and flower development revealed that cell proliferation in the early stages of frond development is active as can be seen in the separate regions corresponding to two budding pouches in the proximal region of the mother frond. L. aequinoctialis produces two stamens of different lengths with the longer stamen growing more rapidly. Using high-throughput RNA sequencing (RNA-seq) and de novo assembly of transcripts from plants induced to flower, we identified the L. aequinoctialis FT and FD genes, whose products in other angiosperms form a transcriptional complex to promote flowering. We characterized the protein-protein interaction of duckweed FT and FD in yeast and examined the functions of the two gene products by overexpression in Arabidopsis. We found that L. aequinoctialis FTL1 promotes flowering, whereas FTL2 suppresses flowering.

DOI： 10.3389/fpls.2021.697206

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

A well-developed root system is essential for efficient water uptake, particularly in drought-prone environments. However, the molecular mechanisms underlying the promotion of root development are poorly understood. We identified and characterized a rice mutant, outstanding rooting1 (our1), which exhibited a well-developed root system. The our1 mutant displayed typical auxin-related phenotypes, including elongated seminal root and defective gravitropism. Seminal root elongation in the our1 mutant was accelerated via the promotion of cell division and elongation. In addition, compared with the wild type, the density of short and thin lateral roots (S-type LRs) was reduced in the our1 mutant, whereas that of long and thick LRs (L-type LRs) was increased. Expression of OUR1, which encodes OsbZIP1, a member of the basic leucine zipper transcription factor family, was observed in the seminal root tip and sites of LR emergence, wherein attenuation of reporter gene expression levels controlled by the auxin response promoter DR5 was also observed in the our1 mutant. Taken together, our results indicate that the our1 gene promotes root development by suppressing auxin signaling, which may be a key factor contributing to an improvement in root architecture.

DOI： 10.1016/j.plantsci.2021.110861

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Plant Biotechnology  

<p>Luciferases have been widely utilized as sensitive reporters to monitor gene expression and protein-protein interactions. Compared to firefly luciferase (Fluc), a recently developed luciferase, Nanoluciferase (NanoLuc or Nluc), has several superior properties such as a smaller size and stronger luminescence activity. We compared the reporter properties of Nluc and Fluc in rice (<i>Oryza sativa</i>). In both plant-based two-hybrid and split luc complementation (SLC) assays, Nluc activity was detected with higher sensitivity and specificity than that with Fluc. To apply Nluc to research involving the photoperiodic regulation of flowering, we made a knock-in rice plant in which the Nluc coding region was inserted in-frame with the <i>OsMADS15</i> gene, a target of the rice florigen Hd3a. Strong Nluc activity in response to Hd3a, and in response to change in day length, was detected in rice protoplasts and in a single shoot apical meristem, respectively. Our results indicate that Nluc assay systems will be powerful tools to monitor gene expression and protein-protein interaction in plant research.</p>

DOI： 10.5511/plantbiotechnology.20.1209a

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Bread wheat is a major crop that has long been the focus of basic and breeding research. Assembly of its genome has been difficult because of its large size and allohexaploid nature (AABBDD genome). Following the first reported assembly of the genome of the experimental strain Chinese Spring (CS), the 10+ Wheat Genomes Project was launched to produce multiple assemblies of worldwide modern cultivars. The only Asian cultivar in the project is Norin 61, a representative Japanese cultivar adapted to grow across a broad latitudinal range, mostly characterized by a wet climate and a short growing season. Here, we characterize key aspects of its chromosome-scale genome assembly spanning 15 Gb with a raw scaffold N50 of 23 Mb. Analysis of the repetitive elements identified chromosomal regions unique to Norin 61 that encompass a tandem array of the pathogenesis-related-13 family. We report novel copy-number variations in the B homeolog of the florigen gene FT1/VRN3, pseudogenization of its D homeolog, and the association of its A homeologous alleles with the spring/winter growth habit. Further, the Norin 61 genome carries typical East Asian functional variants from CS ranging from a single nucleotide to multi-Mb scale. Examples of such variation are the Fhb1 locus, which confers Fusarium head-blight resistance, Ppd-D1a, which confers early flowering, Glu-D1f for Asian noodle quality, and Rht-D1b, which introduced semi-dwarfism during the green revolution. The adoption of Norin 61 as a reference assembly for functional and evolutionary studies will enable comprehensive characterization of the underexploited Asian bread wheat diversity.

DOI： 10.1093/pcp/pcaa152

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Language：Japanese   Publisher：The Japanese Society of Plant Morphology  

<p>The timing of plant reproduction and inflorescence architecture have a large impact on yield of crops. Reproductive development in temperate cereals such as barley and wheat is regulated by two developmental transitions: switching of the identity in the shoot apical meristem (SAM) from vegetative to reproductive phase and conversion of the developmental fate of lateral shoot meristems generated from SAM. Although genetic studies have clarified genetic components and environmental factors that affect inflorescence architecture and its developmental process, little is known about the cellular behavior at the shoot apex including SAM and lateral primordia during development especially in Triticeae crops. We established the 3D-imaging system of barley shoot apex using a clearing method to analyze the cellular dynamics during their developmental process. In this review, we summarize the findings about the morphological characters of the shoot apex in barley and introduce our method of 3D-imaging using the shoot apex of barley.</p>

DOI： 10.5685/plmorphol.33.25

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KEY MESSAGE: The field survey in this article showed in 'KU50', a popular variety and late-branching type of cassava in Southeast Asia, that flowering rarely occurs in normal-field conditions in Southeast Asia but is strongly induced in the dry season in the mountainous region. Flowering time is correlated with the expression patterns of MeFT1 and homologs of Arabidopsis GI, PHYA, and NF-Ys. Cassava (Manihot esculenta Crantz) is a tropical crop that is propagated vegetatively rather than sexually by seed. Flowering rarely occurs in the erect-type variety grown in Southeast Asia, but it is known that cassava produces flowers every year in mountainous regions. Data pertaining to the effect of environmental factors on flowering time and gene expression in cassava, however, is limited. The aim of the present study was to determine the kinds of environmental conditions that regulate flowering time in cassava and the underlying molecular mechanisms. The flowering status of KU50, a popular variety in Southeast Asia and late-branching type of cassava, was monitored in six fields in Vietnam and Cambodia. At non-flowering and flowering field locations in North Vietnam, the two FLOWERING LOCUS T (FT)-like genes, MeFT1 and MeFT2, were characterized by qPCR, and the pattern of expression of flowering-related genes and genes responsive to environmental signals were analyzed by using RNA sequencing data from time-series samples. Results indicate that cassava flowering was induced in the dry season in the mountain region, and that flowering time was correlated with the expression of MeFT1, and homologs of Arabidopsis GI, PHYA, and NF-Ys. Based upon these data, we hypothesize that floral induction in cassava is triggered by some conditions present in the mountain regions during the dry season.

DOI： 10.1007/s11103-020-01057-0

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Agronomically important traits often develop during the later stages of crop growth as consequences of various plant-environment interactions. Therefore, the temporal physiological states that change and accumulate during the crop's life course can significantly affect the eventual phenotypic differences in agronomic traits among crop varieties. Thus, to improve productivity, it is important to elucidate the associations between temporal physiological responses during the growth of different crop varieties and their agronomic traits. However, data representing the dynamics and diversity of physiological states in plants grown under field conditions are sparse. In this study, we quantified the endogenous levels of five phytohormones - auxin, cytokinins (CKs), ABA, jasmonate and salicylic acid - in the leaves of eight diverse barley (Hordeum vulgare) accessions grown under field conditions sampled weekly over their life course to assess the ongoing fluctuations in hormone levels in the different accessions under field growth conditions. Notably, we observed enormous changes over time in the development-related plant hormones, such as auxin and CKs. Using 3' RNA-seq-based transcriptome data from the same samples, we investigated the expression of barley genes orthologous to known hormone-related genes of Arabidopsis throughout the life course. These data illustrated the dynamics and diversity of the physiological states of these field-grown barley accessions. Together, our findings provide new insights into plant-environment interactions, highlighting that there is cultivar diversity in physiological responses during growth under field conditions.

DOI： 10.1093/pcp/pcaa046

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Lateral roots (LRs) determine the overall root system architecture, thus enabling plants to efficiently explore their underground environment for water and nutrients. However, the mechanisms regulating LR development are poorly understood in monocotyledonous plants. We characterized a rice mutant, wavy root elongation growth 1 (weg1), that produced higher number of long and thick LRs (L-type LRs) formed from the curvatures of its wavy parental roots caused by asymmetric cell growth in the elongation zone. Consistent with this phenotype, was the expression of the WEG1 gene, which encodes a putative member of the hydroxyproline-rich glycoprotein family that regulates cell wall extensibility, in the root elongation zone. The asymmetric elongation growth in roots is well known to be regulated by auxin, but we found that the distribution of auxin at the apical region of the mutant and the wild-type roots was symmetric suggesting that the wavy root phenotype in rice is independent of auxin. However, the accumulation of auxin at the convex side of the curvatures, the site of L-type LR formation, suggested that auxin likely induced the formation of L-type LRs. This was supported by the need of a high amount of exogenous auxin to induce the formation of L-type LRs. These results suggest that the MNU-induced weg1 mutated gene regulates the auxin-independent parental root elongation that controls the number of likely auxin-induced L-type LRs, thus reflecting its importance in improving rice root architecture.

DOI： 10.1111/ppl.13063

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In order to train the neural network for plant phenotyping, a sufficient amount of training data must be prepared, which requires time-consuming manual data annotation process that often becomes the limiting step. Here, we show that an instance segmentation neural network aimed to phenotype the barley seed morphology of various cultivars, can be sufficiently trained purely by a synthetically generated dataset. Our attempt is based on the concept of domain randomization, where a large amount of image is generated by randomly orienting the seed object to a virtual canvas. The trained model showed 96% recall and 95% average Precision against the real-world test dataset. We show that our approach is effective also for various crops including rice, lettuce, oat, and wheat. Constructing and utilizing such synthetic data can be a powerful method to alleviate human labor costs for deploying deep learning-based analysis in the agricultural domain.

DOI： 10.1038/s42003-020-0905-5

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>The novel fast atom beam source (FAB) for surface-activated bonding (SAB) method was proposed in order to improve the lifetime of FAB sources. The proposed FAB source achieved the higher efficiency of Ar-FAB irradiation and less wear on the electrodes. This previously study indicated that the applied magnetic fields made the Ar ions converge on the irradiation port, increasing Ar irradiation efficiency. However, it was not measured and not clearly why the proposed FAB source achieved higher performance. In this study, we aim to reveal the factor of achievement high performance and to propose the new structure of the FAB source with much higher performance by plasma analysis. Electrostatic probe studies and the simulation for Ar plasma in the proposed source show that the electron and Ar⁺ density increase near the irradiation port. Moreover, increasing Ar⁺ flux only to the wall with irradiation port indicates improving Ar-FAB irradiation efficiency and suppressing Ar+ sputtering and carbon agglomerates on inside wall of the source.</p>

DOI： 10.1299/jsmemecj.2020.j13105

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

Stem cell maintenance in the shoot apical meristem (SAM) is very important for plant development and is regulated by the WUSCHEL-CLAVATA (WUS-CLV) feedback loop in Arabidopsis (Arabidopsis thaliana). WUS promotes stem cell identity, whereas CLV negatively regulates stem cell proliferation by repressing WUS expression. We previously showed that, in rice (Oryza sativa), the WUS ortholog TILLERS ABSENT1 (TAB1, also known as OsWUS) has no function in SAM maintenance, whereas it plays a crucial role in axillary meristem development. Recently, we showed that a double mutant of FLORAL ORGAN NUMBER2 (FON2) and ABERRANT SPIKELET AND PANICLE1 (ASP1) led to a marked enlargement of the inflorescence meristem, and that the TAB1 function is not associated with massive stem cells in this meristem. In this paper, we confirmed that TAB1 is also unrelated to the enlargement of the SAM in the vegetative phase of the fon2 and fon2 asp1 mutants. In addition, misexpression of TAB1 under the promoter of FON1 led to a slight reduction of the SAM size in wild type, suggesting that TAB1 is not a positive regulator of stem cells. Taking together, TAB1 seems not to be involved in meristem maintenance, irrespective of the meristem type.

DOI： 10.1080/15592324.2019.1640565

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Language：Japanese   Publisher：公益社団法人 精密工学会  

<p>表面活性化接合は半導体分野における三次元積層技術として利用されている．しかし，表面活性化接合に用いられる高速原子ビームガンは，短時間の使用で内部が磨耗してしまう．そこで，高速原子ビームの高効率な照射により，接合回数に対する相対的な長寿命化を目指す新規高速原子ビームガンの開発を行った．また，新規高速原子ビームガンを用いて，その照射特性を評価し，更なる高性能化を目指した設計指針の確立を目指した．</p>

DOI： 10.11522/pscjspe.2019a.0_687

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Stomatal movements are regulated by many environmental signals, such as light, CO2, temperature, humidity, and drought. Recently, we showed that photoperiodic flowering components have positive effects on light-induced stomatal opening in Arabidopsis thaliana. In this study, we determined that light-induced stomatal opening and increased stomatal conductance were larger in plants grown under long-day (LD) conditions than in those grown under short-day (SD) conditions. Gene expression analyses using purified guard cell protoplasts revealed that FT and SOC1 expression levels were significantly increased under LD conditions. Interestingly, the enhancement of light-induced stomatal opening and increased SOC1 expression in guard cells due to LD conditions persisted for at least 1 week after plants were transferred to SD conditions. We then investigated histone modification using chromatin immunoprecipitation-PCR, and observed increased trimethylation of lysine 4 on histone 3 (H3K4) around SOC1. We also found that LD-dependent enhancement of light-induced stomatal opening and H3K4 trimethylation in SOC1 were suppressed in the ft-2 mutant. These results indicate that photoperiod is an important environmental cue regulating stomatal opening, and that LD conditions enhance light-induced stomatal opening and epigenetic modification (H3K4 trimethylation) around SOC1, a positive regulator of stomatal opening, in an FT-dependent manner. Thus, this study provides novel insights into stomatal responses to photoperiod.

DOI： 10.1038/s41598-019-46440-0

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We developed and modified a precise, rapid, and reproducible protocol isolating high-quality RNA from tissues of multiple varieties of cassava plants (Manihot esculenta Crantz). The resulting method is suitable for use in mini, midi, and maxi preparations and rapidly achieves high total RNA yields (170-600 μg·g-1) using low-cost chemicals and consumables and with minimal contamination from polysaccharides, polyphenols, proteins, and other secondary metabolites. In particular, A260 : A280 ratios were > 2.0 for RNA from various tissues, and all of the present RNA samples yielded ribosomal integrity number values of greater than six. The resulting high purity and quality of isolated RNA will facilitate downstream applications (quantitative reverse transcriptase-polymerase chain reaction or RNA sequencing) in cassava molecular breeding.

DOI： 10.1002/2211-5463.12561

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Language：English   Publisher：International Journal of Molecular Sciences  

(1) Background: Silene latifolia is a dioecious plant, whose sex is determined by XY-type sex chromosomes. Microbotryum lychnidis-dioicae is a smut fungus that infects S. latifolia plants and causes masculinization in female flowers, as if Microbotryum were acting as a sex-determining gene. Recent large-scale sequencing efforts have promised to provide candidate genes that are involved in the sex determination machinery in plants. These candidate genes are to be analyzed for functional characterization. A virus vector can be a tool for functional gene analyses; (2) Methods: To develop a viral vector system in S. latifolia plants, we selected Apple latent spherical virus (ALSV) as an appropriate virus vector that has a wide host range; (3) Results: Following the optimization of the ALSV inoculation method, S. latifolia plants were infected with ALSV at high rates in the upper leaves. In situ hybridization analysis revealed that ALSV can migrate into the flower meristems in S. latifolia plants. Successful VIGS (virus-induced gene silencing) in S. latifolia plants was demonstrated with knockdown of the phytoene desaturase gene. Finally, the developed method was applied to floral organ genes to evaluate its usability in flowers; (4) Conclusion: The developed system enables functional gene analyses in S. latifolia plants, which can unveil gene functions and networks of S. latifolia plants, such as the mechanisms of sex determination and fungal-induced masculinization.

DOI： 10.3390/ijms20051031

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press  

Hd3a, a rice homolog of FLOWERING LOCUS T (FT), is a florigen that induces flowering. Hd3a forms a ternary - florigen activation complex' (FAC) with 14-3-3 protein and OsFD1 transcription factor, a rice homolog of FD that induces transcription of OsMADS15, a rice homolog of APETALA1 (AP1), which leads to flowering. TERMINAL FLOWER 1 (TFL1) represses flowering and controls inflorescence architecture. However, the molecular basis for floral repression by TFL1 remains poorly understood. Here we show that RICE CENTRORADIALIS (RCN), rice TFL1-like proteins, compete with Hd3a for 14-3-3 binding. All four RCN genes are predominantly expressed in the vasculature, and RCN proteins are transported to the shoot apex to antagonize florigen activity and regulate inflorescence development. The antagonistic function of RCN to Hd3a is dependent on its 14-3-3 binding activity. Our results suggest a molecular basis for regulation of the balance between florigen FT and anti-florigen TFL1.

DOI： 10.1093/pcp/pcy021

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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>Surface activated bonding (SAB) is used in three-dimensional laminating technology for such as LSI chips. Ar fast atom beam (FAB) is used for SAB. However, there is a serious problem that the conventional FAB gun can be often used for only hundreds of minutes because abrasion powders are generated from the worn part due to Ar⁺ sputtering in the gun. Therefore, it is the purpose of this work to develop a new FAB gun to realize longer life. We developed the novel FAB gun applied with a magnetic field to control Ar⁺ motion and reduce the sputtering in the gun. Furthermore, the disposition of the carbon electrodes in the gun was changed. As a result, we succeeded in 3 times Ar emission efficiency due to applying the magnetic field. And we unconfirmed abrasion powder in the novel FAB gun after 5200 minutes irradiation experiments. As written above, the novel FAB gun was able to function as expected.</p>

DOI： 10.1299/jsmemecj.2018.j1110203

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japanese Society of Plant Morphology  

<p>Florigen is a mobile signal that initiates flowering, which is generated in leaves in response to various environmental stimuli and is transported to the shoot apical meristem (SAM) in plants. The molecular nature of florigen was found to be proteins encoded by the gene <i>FLOWERING LOCUS T</i> (<i>FT</i>) and its orthologs. Recent progress in the molecular biology of florigen revealed its receptors and a transcriptional complex composed of florigen, receptor and transcription factors. <i>In vivo</i> imaging of florigen distribution in the shoot apex and inside a cell contributed to elucidate the essential mechanisms for florigen function. In rice shoot apex, distribution of florigen is clearly visualized by expression of FT protein fused with green fluorescent protein (GFP), and the spatial patterns of downstream gene expression are also visualized by various techniques. At the cellular level, the distribution of florigen and its receptor complex is observed through bimolecular fluorescent complementation (BiFC), which revealed dynamic changes of subcellular localization for florigen and related proteins during the formation of florigen-receptor complex. Here the technique for dissecting SAM is presented to show how SAM samples are prepared for imaging florigen, and recent advances in the regulation of flowering in relation to the contributions from the application of imaging techniques are summarized.</p>

DOI： 10.5685/plmorphol.29.27

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Authorship：Lead author,　Corresponding author   Language：English   Publisher：Japanese Society of Breeding  

<p>Florigen is a mobile flowering signal in plants that has a strong impact on plant reproduction and is considered one of the important targets for crop improvement. At the molecular level, florigen is represented as a protein product encoded by the <i>FLOWERING LOCUS T</i> (<i>FT</i>) gene, which is highly conserved across flowering plants and thus the understanding of this protein is expected to be applied to the improvement of many crops. Recent advances in molecular genetics, cell biology and structural biology in plants revealed the presence of intercellular receptors for florigen, a transcriptional complex essential for florigen to function, and also shed light on the molecular basis of pleiotropic function of florigen beyond flowering. Furthermore, cutting-edge technologies, such as live cell imaging and next generation sequencing revealed the precise distribution of florigen and transcriptional targets of the florigen activation complex (FAC) during early stages of floral transition. These understandings will help future crop improvement through the regulation of flowering and other plant developmental processes.</p>

DOI： 10.1270/jsbbs.17026

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Accumulating evidence indicates that the FLOWERING LOCUST (FT) protein is the mobile floral signal known as florigen. A rice FT homolog, Heading date3a (Hd3a), is transported from the phloem to shoot apical cells, where it interacts with 14-3-3 proteins and transcription factor OsFD1 to form a florigen activation complex (FAC) that activates a rice homolog of the floral identity gene APETALA1. Recent studies showed that florigen has roles in plant development beyond flowering; however, the exact nature of these roles is not well understood. It is not clear whether FT is transported to organs outside the shoot apex, and whether FAC formation is required for processes other than flowering. We show here that the Hd3a protein accumulates in axillary meristems to promote branching, and that FAC formation is required. Analysis of transgenic plants revealed that Hd3a promotes branching through lateral bud outgrowth. Hd3a protein produced in the phloem reached the axillary meristem in the lateral bud, and its transport was required for promotion of branching. Moreover, mutant Hd3a proteins defective in FAC formation but competent with respect to transport did not promote branching. Finally, we show that Hd3a promotes branching independently from strigolactone and FC1, a transcription factor that inhibits branching in rice. Together, these results suggest that Hd3a functions as a mobile signal for branching in rice.
Significance Statement Accumulating evidence indicates that FLOWERING LOCUS T (FT) protein is the mobile floral signal florigen. Recent studies highlight that florigen may play multiple roles beyond flowering, whereas importance of mobile nature and molecular mechanism underling pleiotropic function remain unknown. We show here that phloem-expressed Hd3a protein accumulated in the distant axillary meristems to promote branching and that FAC formation was required, suggesting that Hd3a functions as a mobile signal for branching in rice.

DOI： 10.1111/tpj.12811

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Cell-to-cell communication is a fundamental mechanism for coordinating developmental and physiological events in multicellular organisms. Heterotrimeric G proteins are key molecules that transmit extracellular signals; similarly, CLAVATA signaling is a crucial regulator in plant development. Here, we show that Arabidopsis thaliana G mutants exhibit an enlarged stem cell region, which is similar to that of clavata mutants. Our genetic and cell biological analyses suggest that the G protein beta-subunit1 AGB1 and RPK2, one of the major CLV3 peptide hormone receptors, work synergistically in stem cell homeostasis through their physical interactions. We propose that AGB1 and RPK2 compose a signaling module to facilitate meristem development.

DOI： 10.15252/embr.201438660

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Background: The rice interactome, in which a network of protein-protein interactions has been elucidated in rice, is a useful resource to identify functional modules of rice signal transduction pathways. Protein-protein interactions occur in cells in two ways, constitutive and regulative. While a yeast-based high-throughput method has been widely used to identify the constitutive interactions, a method to detect the regulated interactions is rarely developed for a large-scale analysis.
Results: A split luciferase complementation assay was applied to detect the regulated interactions in rice. A transformation method of rice protoplasts in a 96-well plate was first established for a large-scale analysis. In addition, an antibody that specifically recognizes a carboxyl-terminal fragment of Renilla luciferase was newly developed. A pair of antibodies that recognize amino-and carboxyl-terminal fragments of Renilla luciferase, respectively, was then used to monitor quality and quantity of interacting recombinant-proteins accumulated in the cells. For a proof-of-concept, the method was applied to detect the gibberellin-dependent interaction between GIBBERELLIN INSENSITIVE DWARF1 and SLENDER RICE 1.
Conclusions: A method to detect regulated protein-protein interactions was developed towards establishment of the rice interactome.

DOI： 10.1186/s12284-014-0011-8

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Academic Press  

Florigen is a systemic signal that promotes flowering. Its molecular nature is a conserved FLOWERING LOCUS T (FT) protein that belongs to the PEBP family. FT is expressed in the leaf phloem and transported to the shoot apical meristem where it initiates floral transition. In the cells of the meristem, FT binds 14-3-3 proteins and bZIP transcription factor FD to form the florigen activation complex, FAC, which activates floral meristem identity genes such as AP1. The FAC model provides molecular basis for multiple functions of FT beyond flowering through changes of its partners and transcriptional targets. The surface of FT protein includes several regions essential for transport and functions, suggesting the binding of additional components that support its function. FT expression is under photoperiodic control, involving a conserved GIGANTEA-CONSTANS-FT regulatory module with species-specific modifications that contribute variations of flowering time in natural populations.

DOI： 10.1016/B978-0-12-801922-1.00005-1

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Authorship：Lead author   Language：English   Publisher：CURRENT BIOLOGY LTD  

Regulation of flowering time directly influences successful rice grain production; thus, the long history of domestication and breeding has improved the genetic network of flowering. Recent advances using molecular genomic approaches have revealed the targets of these modifications and the underlying molecular mechanism for flowering. These efforts contributed to identifying the molecular nature of the systemic floral signal `florigen' and have shown how florigen functions, how florigen expression is controlled, and how regulatory pathways are diversified. In this review, we summarize the advances in our understanding of the detailed molecular and genetic mechanisms that allow rice plants to produce flowers at the proper time to ensure grain production.

DOI： 10.1016/j.pbi.2013.01.005

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Language：English   Publisher：ELSEVIER SCIENCE LONDON  

In the 1930s, the flowering hormone, florigen, was proposed to be synthesized in leaves under inductive day length and transported to the shoot apex, where it induces flowering. More recently, generated genetic and biochemical data suggest that florigen is a protein encoded by the gene, FLOWERING LOCUS T (FT). A rice (Oryza sativa) FT homolog, Hd3a, interacts with the rice FD homolog, OsFD1, via a 14-3-3 protein. Formation of this tri-protein complex is essential for flowering promotion by Hd3a in rice. In addition, the multifunctionality of FT homologs, other than for flowering promotion, is an emerging concept. Here we review the structural and biochemical features of the florigen protein complex and discuss the molecular basis for the multifunctionality of FT proteins.

DOI： 10.1016/j.tplants.2013.02.002

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Florigen, a protein encoded by the FLOWERING LOCUS T (FT) in Arabidopsis and Heading date 3a (Hd3a) in rice, is the universal flowering hormone in plants. Florigen is transported from leaves to the shoot apical meristem and initiates floral evocation. In shoot apical cells, conserved cytoplasmic 14-3-3 proteins act as florigen receptors. A hexameric florigen activation complex (FAC) composed of Hd3a, 14-3-3 proteins, and OsFD1, a transcription factor, activates OsMADS15, a rice homolog of Arabidopsis APETALA1, leading to flowering. Because FD is a key component of the FAC, we characterized the FD gene family and their functions. Phylogenetic analysis of FD genes indicated that this family is divided into two groups: (i) canonical FD genes that are conserved among eudicots and non-Poaceae monocots; and (ii) Poaceae-specific FD genes that are organized into three subgroups: Poaceae FD1, FD2 and FD3. The Poaceae FD1 group shares a small sequence motif, T(A/V)LSLNS, with FDs of eudicots and non-Poaceae monocots. Overexpression of OsFD2, a member of the Poaceae FD2 group, produced smaller leaves with shorter plastochrons, suggesting that OsFD2 controls leaf development. In vivo subcellular localization of Hd3a, 14-3-3 and OsFD2 suggested that in contrast to OsFD1, OsFD2 is restricted to the cytoplasm through its interaction with the cytoplasmic 14-3-3 proteins, and interaction of Hd3a with 14-3-3 facilitates nuclear translocation of the FAC containing OsFD2. These results suggest that FD function has diverged between OsFD1 and OsFD2, but formation of a FAC is essential for their function.

DOI： 10.1093/pcp/pct005

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DOI： 10.1007/978-1-4614-7903-1_18

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Photoperiodic control of flowering time consists of a complicated network that converges into the generation of a mobile flowering signal called florigen. Recent advances identifying the protein FT/Hd3a as the molecular nature responsible for florigen activity have focused current research on florigen genes as the important output of this complex signaling network. Rice is a model system for short-day plants and recent progress in elucidating the flowering network from rice and Arabidopsis, a long-day plant, provides an evolutionarily comparative view of the photoperiodic flowering pathway. This review summarizes photoperiodic flowering control in rice, including the interaction of complex layers of gene networks contributed from evolutionarily unique factors and the regulatory adaptation of conserved factors.

DOI： 10.1016/j.pbi.2010.08.016

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The DELLA protein SLENDER RICE1 (SLR1) is a repressor of gibberellin (GA) signaling in rice (Oryza sativa), and most of the GA-associated responses are induced upon SLR1 degradation. It is assumed that interaction between GIBBERELLIN INSENSITIVE DWARF1 (GID1) and the N-terminal DELLA/TVHYNP motif of SLR1 triggers F-box protein GID2-mediated SLR1 degradation. We identified a semidominant dwarf mutant, Slr1-d4, which contains a mutation in the region encoding the C-terminal GRAS domain of SLR1 (SLR1(G576V)). The GA-dependent degradation of SLR1(G576V) was reduced in Slr1-d4, and compared with SLR1, SLR1(G576V) showed reduced interaction with GID1 and almost none with GID2 when tested in yeast cells. Surface plasmon resonance of GID1-SLR1 and GID1-SLR1(G576V) interactions revealed that the GRAS domain of SLR1 functions to stabilize the GID1-SLR1 interaction by reducing its dissociation rate and that the G576V substitution in SLR1 diminishes this stability. These results suggest that the stable interaction of GID1-SLR1 through the GRAS domain is essential for the recognition of SLR1 by GID2. We propose that when the DELLA/TVHYNP motif of SLR1 binds with GID1, it enables the GRAS domain of SLR1 to interact with GID1 and that the stable GID1-SLR1 complex is efficiently recognized by GID2.

DOI： 10.1105/tpc.110.075549

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Hd3a and FT proteins have recently been proposed to act as florigens in rice and Arabidopsis, respectively; however, the molecular mechanisms of their function remain to be determined. In this study, we identified GF14c (a 14-3-3 protein) as an Hd3a-interacting protein in a yeast two-hybrid screen. In vitro and in vivo experiments, using a combination of pull-down assays and bimolecular fluorescence complementation, confirmed the interaction between Hd3a and GF14c. Functional analysis using either GF14c overexpression or knockout transgenic rice plants indicated that this interaction plays a role in the regulation of flowering. GF14c-overexpressing plants exhibited a delay in flowering and the knockout mutants displayed early flowering relative to the wild-type plants under short-day conditions. These results suggest that GF14c acts as a negative regulator of flowering by interacting with Hd3a. Since the 14-3-3 protein has been shown to interact with FT protein in tomato and Arabidopsis, our results in rice provide important findings about FT signaling in plants.

DOI： 10.1093/pcp/pcp012

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Authorship：Lead author   Language：English   Publisher：SPRINGER  

Flowering time is a key trait for geographical and seasonal adaptation of plants and is an important consideration for rice breeders. Recently identified genetic factors provide new insights into this complex trait. The list of genes involved in flowering and their functions tells us that the molecular basis of day-length measurement includes both of the evolution of unique factors and the regulatory adaptation of conserved factors in rice. This information helped identify rice florigen, a mobile flowering signal. Our current view of flowering time regulation incorporates the presence of complex layers of gene networks integrated with the synthesis of florigen protein and its subsequent transport and perception.

DOI： 10.1007/s12284-008-9005-8

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GAMYB is a component of gibberellin (GA) signaling in cereal aleurone cells, and has an important role in flower development. However, it is unclear how GAMYB function is regulated. We examined the involvement of a microRNA, miR159, in the regulation of GAMYB expression in cereal aleurone cells and flower development. In aleurone cells, no miR159 expression was observed with or without GA treatment, suggesting that miR159 is not involved in the regulation of GAMYB and GAMYB-like genes in this tissue. miR159 was expressed in tissues other than aleurone, and miR159 over-expressors showed similar but more severe phenotypes than the gamyb mutant. GAMYB and GAMYB-like genes are co-expressed with miR159 in anthers, and the mRNA levels for GAMYB and GAMYB-like genes are negatively correlated with miR159 levels during anther development. Thus, OsGAMYB and OsGAMYB-like genes are regulated by miR159 in flowers. A microarray analysis revealed that OsGAMYB and its upstream regulator SLR1 are involved in the regulation of almost all GA-mediated gene expression in rice aleurone cells. Moreover, different sets of genes are regulated by GAMYB in aleurone cells and anthers. GAMYB binds directly to promoter regions of its target genes in anthers as well as aleurone cells. Based on these observations, we suggest that the regulation of GAMYB expression and GAMYB function are different in aleurone cells and flowers in rice.

DOI： 10.1111/j.1365-313X.2006.02795.x

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Histone modifications such as methylation and acetylation in the chromatin surrounding a gene are thought to regulate transcriptional activity. In this study, to determine whether dynamic changes occur in histone modification on the loci of stress-responsive genes in plants, we chose rice submergence-inducible ADH1 and PDC1 genes. When submerged, the rice ADH1 and PDC1 genes were activated in a biphasic manner: the first and second inductions occurred after approximately 2 and 12 h of submergence, respectively. Their expression was transcriptionally induced as shown by increased binding of RNA polymerase II to the ADH1 and PDC1 loci during submergence. The Lys4 residues of the histone H3 proteins (H3-K4s) at both the 5'- and 3'-coding regions of ADH1 and PDC1 were found to change from a di-methylated state to a tri-methylated state at the first induction period. On the other hand, acetylation of H3 increased throughout ADH1 and PDC1 genes at the later induction period. The methylation and acetylation levels recovered to the initial levels during re-aeration. Treatment of seedlings with a histone deacetylase (HDAC) inhibitor, trichostatin A, increased acetylation of histones H3 and association of RNA polymerase II on the ADH1 and PDC1 loci, thereby increasing transcript levels of ADH1 and PDC1. Together, these results showed dynamic and reversible changes of histone H3-K4 methylation and H3 acetylation in stress-responsive genes in a higher plant in response to the appearance or disappearance of an environmental stress.

DOI： 10.1093/pcp/pcj072

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Publisher：The Japanese Society of Plant Physiologists  

DELLA proteins, which are a subgroup of GRAS proteins, are key factors of gibberellin (GA) signaling. Our previous studies revealed that, in rice cells, DELLA protein SLR1 functions as a repressor for GA action and is degraded GA-dependently by ubiquitin-proteasome system through the SCF<SUP>GID2</SUP> function. However, it is unclear how the GA signal is transduced to SLR1 from bioactive GA molecular. Recently, we succeeded to identify a GA receptor, which has a similar primary structure to that of hormone sensitive lipase and is localized in nucleus. Interestingly, the yeast two-hybrid assay revealed that the interaction between GID1 and SLR1 occurs as a GA dependent manner. Thus we speculate that the complex composed by GID1, SLR1, and GA may recruit an F-box protein, GID2, to initiate the degradation of SLR1. To evaluate this, we have performed some biochemical experiments such as yeast three hybrid assay and pull-down assay in vitro.

DOI： 10.14841/jspp.2006.0.404.0

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer Netherlands  

Oxygen deprivation induced by submergence, flooding and waterlogging is an environmental stress that affects the growth of plants and production of crops. Plants undergo metabolic and morphological changes to avoid or alleviate the stresses arising from low oxygen conditions. One well-known metabolic change is activation of the glycolytic and fermentation pathways, which are important for ATP production under anaerobic conditions. In some plant species, morphological changes include elongation of internodes or petioles, aerenchyma formation and formation of a barrier to radial oxygen loss. Under post-anoxic conditions, plants suffer from injurious substances, reactive oxygen species and acetaldehyde. Plants have various mechanisms for metabolizing these harmful molecules to prevent or alleviate post-anoxic injuries. This paper reviews the current understanding of adaptation and tolerance mechanisms of plants that are activated under low oxygen conditions and following re-aeration. © 2006 Springer. Printed in the Netherlands. © 2006 Springer. All Rights Reserved.

DOI： 10.1007/1-4020-4389-9_7

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Language：Japanese   Publisher：The Japanese Society of Plant Physiologists  

GAMYB was first isolated as a positive transcriptional regulator of gibberellin (GA)-dependent α-amylase expression in barley endosperm, and its molecular properties has been extensively characterized. Here, we report the role and the regulation of GAMYB and structurally related GAMYB-like proteins in rice growth. We found that <I>GAMYB</I> and <I>GAMYB-like</I> genes contain a target site for a microRNA, miR159, and overexpression of miR159 in rice plant revealed not only the regulatory mode of miR159 on these genes but also the role of these genes in rice growth. On the other hand, microarray experiment revealed that almost all of GA-regulated genes did not respond to GA in the endosperm of <I>gamyb</I>. This suggests that GAMYB is involved in the regulation of almost all GA-mediated gene expression in rice endosperm. <br>This work was in part supported by PROBRAIN.

DOI： 10.14841/jspp.2005.0.031.0

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Post-hypoxic injuries in plants are primarily caused by bursts of reactive oxygen species and acetaldehyde. In agreement with previous studies, we found accumulations of acetaldehyde in rice during re-aeration following submergence. During re-aeration, acetaldehyde-oxidizing aldehyde dehydrogenase (ALDH) activity increased, thereby causing the acetaldehyde content to decrease in rice. Interestingly, re-aerated rice plants showed an intense mitochondrial ALDH2a protein induction, even though ALDH2a mRNA was submergence induced and declined upon re-aeration. This suggests that rice ALDH2a mRNA is accumulated in order to quickly metabolize acetaldehyde that is produced upon re-aeration.

DOI： 10.1016/S0014-5793(03)00631-8

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Recent studies have suggested that mitochondrial aldehyde dehydrogenase (aldehyde:NAD(P)(+) oxidoreductase, EC 1.2.1.3) (ALDH2) plays essential roles in pollen development in plants. Rice (Oryza sativa L.) ALDH2 is encoded by at least two ALDH2 genes, one of which (ALDH2a) was previously identified. In this study, to understand the roles of ALDH2 in rice, we isolated and characterized a cDNA clone encoding another rice ALDH2 (ALDH2b). An in vitro ALDH assay indicated that ALDH2b possesses an NAD(+)-linked activity for oxidation of acetaldehyde, glycolaldehyde and propionaldehyde. Northern blot and immunoblot analyses revealed that ALDH2b was constitutively present in all the organs examined, whereas ALDH2a was expressed in leaves of dark-grown seedlings and panicles. By RFLP linkage mapping, the ALDH2a and ALDH2b genes were mapped to the long arm of chromosome 2 and the short arm of chromosome 6, respectively. We suggest that the rice ALDH2a and ALDH2b genes are orthologues of maize mitochondrial ALDH genes, rf2b and rf2a, respectively.

DOI： 10.1016/S0378-1119(03)00383-4

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DOI： 10.1016/S0378-1119(03)00383-4,

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J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：English   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)   Publisher：JAPANESE SOC BREEDING  

Acetaldehyde is oxidized from anaerobically accumulated ethanol during re-aeration in plants and may cause post-anoxic (post-hypoxic) injury. Aldehyde dehydrogenase (ALDH) can metabolize acetaldehyde to acetate, which is much less toxic. To understand the role of ALDH in alleviating post-anoxic injury of plants, we analyzed the expression of the mitochondrial ALDH genes, rf2a and rf2b, and determined the ethanol and acetaldehyde contents under submergence and subsequent re-aeration in a submergence-intolerant plant, maize (Zea mays L., inbred line B73). The level of rf2a mRNA decreased, whereas that of rf2b mRNA increased under submerged conditions. When the submerged plants were re-aerated, the transcript levels returned to the original levels. The level of mitochondrial ALDH proteins decreased under submergence and remained unchanged under re-aeration. The ALDH activity decreased under submergence and, during reaeration, recovered to the original level much more slowly than in the case of rice (Oryza sativa L.). The content of acetaldehyde, which was produced under submergence, further increased following re-aeration. These results suggest that the lower submergence tolerance of maize compared to that of rice is partly due to a weaker ALDH activity during re-aeration.

DOI： 10.1270/jsbbs.56.365

Web of Science

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：English   Publishing type：Research paper, summary (international conference)   Publisher：OXFORD UNIV PRESS  

Web of Science

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Event date： 2024.7

Language：Japanese   Presentation type：Poster presentation  

Venue：東京大学   Country：Japan  

Event date： 2024.6

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：大阪市中央公会堂   Country：Japan  

Event date： 2024.6

Language：Japanese   Presentation type：Poster presentation  

Venue：大阪市中央公会堂   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Symposium, workshop panel (nominated)  

Venue：東北大学   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：帯広畜産大学   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Poster presentation  

Venue：帯広畜産大学   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Poster presentation  

Venue：帯広畜産大学   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：帯広畜産大学   Country：Japan  

Event date： 2022.6

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：岡山大学資源植物科学研究所   Country：Japan  

Language：English   Presentation type：Oral presentation (invited, special)  

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Language：English   Presentation type：Oral presentation (keynote)  

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Language：English   Presentation type：Oral presentation (keynote)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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実験室内での組織・形態学、発生学、動物生理学、植物生理学、遺伝学に関する実験から東郷フィールドにおける生物生産実習、および農業経済学実習まで幅広い実験や実習を行う。

３年次までに習得した専門知識を踏まえ，各研究室における卒業論文研究にいたるまでの橋渡しとなるような項目について講義や実習を行う。「植物ゲノム利用学」では，近年，急増している植物ゲノムビックデータを利用した育種学研究分野についての知識を習得する。「アイソトープ実験法」では，本学において卒業研究等でラジオアイソトープを使用するための利用資格を得ることを目的として，ラジオアイソトープ取り扱いの基礎知識と技術を学ぶ。「国際農学演習」では，「海外実地研修」および「海外学生受入研修」を受講するにあたり，グループワークと英語での発表を通して，研修先についての基礎知識を身に付ける。「生物データベース利用演習」では，ゲノムデータベース取扱の初歩について，PCを用いた講義・演習を行う。

この講義の目的は，「生命農学における学術・研究の概要」，「生命農学の社会的使命」，「今後履修する基礎および専門科目の必要性」，「習得した知識・技能の将来展開」を理解することである。また，各学科の理念や各研究室の研究背景・現状・将来を知ることで，今後４年間の学修の方向性や取り組み方を考えるきっかけを得る。生命農学に対する知的好奇心を高めるとともに，科学，技術，社会への視野を広げることによって，勉学意欲の向上・今後の大学生活への期待を一層高める。

植物生理学２では，植物の個体形成と分化の柔軟性について学ぶ。また，植物の発生・成長・分化の制御機構に関する理解を深める。すなわち，胚発生から種子をへて栄養成長に至る過程、栄養成長から生殖成長への転換と受精、結実に至る各項目を習得する。