研究者詳細 - 髙橋　宏和

Leaf Gas Film 1 promotes glycerol ester accumulation and formation of a tight root barrier to radial O2 loss in rice. 査読有り国際誌

Jiménez JC, Noorrohmah S, Suresh K, Zeisler-Diehl VV, Peralta Ogorek LL, Herzog M, Pellegrini E, Nagai K, Ashikari M, Takahashi H, Pedersen O, Schreiber L, Nakazono M

Plant physiology 196 巻 ( 4 ) 頁： 2437 - 2449 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Physiology

Rice (Oryza sativa L.) and many other wetland plants form an apoplastic barrier in the outer parts of the roots to restrict radial O<inf>2</inf> loss to the rhizosphere during soil flooding. This barrier facilitates longitudinal internal O<inf>2</inf> diffusion via gas-filled tissues from shoot to root apices, enabling root growth in anoxic soils. We tested the hypothesis that Leaf Gas Film 1 (LGF1), which influences leaf hydrophobicity in rice, plays a crucial role in tight outer apoplastic barrier formation in rice roots. We examined the roots of a rice mutant (dripping wet leaf 7, drp7) lacking functional LGF1, its wild type, and an LGF1 overexpression line for their capacity to develop outer apoplastic barriers that restrict radial O<inf>2</inf> loss. We quantified the chemical composition of the outer part of the root and measured radial O<inf>2</inf> diffusion from intact roots. The drp7 mutant exhibited a weak barrier to radial O<inf>2</inf> loss compared to the wild type. However, introducing functional LGF1 into the mutant fully restored tight barrier function. The formation of a tight barrier to radial O<inf>2</inf> loss was associated with increased glycerol ester levels in exodermal cells, rather than differences in total root suberization or lignification. These results demonstrate that, in addition to its role in leaf hydrophobicity regulation, LGF1 plays an important role in controlling the function of the outer apoplastic barriers in roots. Our study suggests that increased deposition of glycerol esters in the suberized root exodermis establishes a tight barrier to radial O<inf>2</inf> loss in rice roots.

DOI： 10.1093/plphys/kiae458

Transcriptome Analysis of Rice Root Tips Reveals Auxin, Gibberellin and Ethylene Signaling Underlying Nutritropism. 査読有り

Yamazaki K, Ohmori Y, Takahashi H, Toyoda A, Sato Y, Nakazono M, Fujiwara T

Plant & cell physiology 65 巻 ( 4 ) 頁： 671 - 679 2024年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant and Cell Physiology

Nutritropism is a positive tropism toward nutrients in plant roots. An NH4+ gradient is a nutritropic stimulus in rice (Oryza sativa L.). When rice roots are exposed to an NH4+ gradient generated around nutrient sources, root tips bend toward and coil around the sources. The molecular mechanisms are largely unknown. Here, we analyzed the transcriptomes of the inside and outside of bending root tips exhibiting nutritropism to reveal nutritropic signal transduction. Tissues facing the nutrient sources (inside) and away (outside) were separately collected by laser microdissection. Principal component analysis revealed distinct transcriptome patterns between the two tissues. Annotations of 153 differentially expressed genes implied that auxin, gibberellin and ethylene signaling were activated differentially between the sides of the root tips under nutritropism. Exogenous application of transport and/or biosynthesis inhibitors of these phytohormones largely inhibited the nutritropism. Thus, signaling and de novo biosynthesis of the three phytohormones are necessary for nutritropism. Expression patterns of IAA genes implied that auxins accumulated more in the inside tissues, meaning that ammonium stimulus is transduced to auxin signaling in nutritropism similar to gravity stimulus in gravitropism. SAUR and expansin genes, which are known to control cell wall modification and to promote cell elongation in shoot gravitropism, were highly expressed in the inside tissues rather than the outside tissues, and our transcriptome data are unexplainable for differential elongation in root nutritropism.

DOI： 10.1093/pcp/pcae003

Outer apoplastic barriers in roots: prospects for abiotic stress tolerance. 国際誌 Open Access

Peralta Ogorek LL, Jiménez JC, Visser EJW, Takahashi H, Nakazono M, Shabala S, Pedersen O

Functional plant biology : FPB 51 巻 ( 1 ) 頁： NULL 2024年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Functional Plant Biology

Floods and droughts are becoming more frequent as a result of climate change and it is imperative to find ways to enhance the resilience of staple crops to abiotic stresses. This is crucial to sustain food production during unfavourable conditions. Here, we analyse the current knowledge about suberised and lignified outer apoplastic barriers, focusing on the functional roles of the barrier to radial O<inf>2</inf> loss formed as a response to soil flooding and we discuss whether this trait also provides resilience to multiple abiotic stresses. The barrier is composed of suberin and lignin depositions in the exodermal and/or sclerenchyma cell walls. In addition to the important role during soil flooding, the barrier can also restrict radial water loss, prevent phytotoxin intrusion, salt intrusion and the main components of the barrier can impede invasion of pathogens in the root. However, more research is needed to fully unravel the induction pathway of the outer apoplastic barriers and to address potential trade-offs such as reduced nutrient or water uptake. Nevertheless, we suggest that the outer apoplastic barriers might act as a jack of all trades providing tolerance to multiple abiotic and/or biotic stressors.

DOI： 10.1071/FP23133

Single-cell transcriptomic analysis of pea shoot development and cell-type-specific responses to boron deficiency. 国際誌 Open Access

Chen X, Ru Y, Takahashi H, Nakazono M, Shabala S, Smith SM, Yu M

The Plant journal : for cell and molecular biology 117 巻 ( 1 ) 頁： 302 - 322 2024年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Journal

Understanding how nutrient stress impacts plant growth is fundamentally important to the development of approaches to improve crop production under nutrient limitation. Here we applied single-cell RNA sequencing to shoot apices of Pisum sativum grown under boron (B) deficiency. We identified up to 15 cell clusters based on the clustering of gene expression profiles and verified cell identity with cell-type-specific marker gene expression. Different cell types responded differently to B deficiency. Specifically, the expression of photosynthetic genes in mesophyll cells (MCs) was down-regulated by B deficiency, consistent with impaired photosynthetic rate. Furthermore, the down-regulation of stomatal development genes in guard cells, including homologs of MUTE and TOO MANY MOUTHS, correlated with a decrease in stomatal density under B deficiency. We also constructed the developmental trajectory of the shoot apical meristem (SAM) cells and a transcription factor interaction network. The developmental progression of SAM to MC was characterized by up-regulation of genes encoding histones and chromatin assembly and remodeling proteins including homologs of FASCIATA1 (FAS1) and SWITCH DEFECTIVE/SUCROSE NON-FERMENTABLE (SWI/SNF) complex. However, B deficiency suppressed their expression, which helps to explain impaired SAM development under B deficiency. These results represent a major advance over bulk-tissue RNA-seq analysis in which cell-type-specific responses are lost and hence important physiological responses to B deficiency are missed. The reported findings reveal strategies by which plants adapt to B deficiency thus offering breeders a set of specific targets for genetic improvement. The reported approach and resources have potential applications well beyond P. sativum species and could be applied to various legumes to improve their adaptability to multiple nutrient or abiotic stresses.

DOI： 10.1111/tpj.16487

High-Throughput Phenotyping of Soybean Biomass: Conventional Trait Estimation and Novel Latent Feature Extraction Using UAV Remote Sensing and Deep Learning Models. 査読有り

Okada M, Barras C, Toda Y, Hamazaki K, Ohmori Y, Yamasaki Y, Takahashi H, Takanashi H, Tsuda M, Hirai MY, Tsujimoto H, Kaga A, Nakazono M, Fujiwara T, Iwata H

Plant phenomics (Washington, D.C.) 6 巻頁： 0244 2024年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plant Phenomics

High-throughput phenotyping serves as a framework to reduce chronological costs and accelerate breeding cycles. In this study, we developed models to estimate the phenotypes of biomass-related traits in soybean (Glycine max) using unmanned aerial vehicle (UAV) remote sensing and deep learning models. In 2018, a field experiment was conducted using 198 soybean germplasm accessions with known whole-genome sequences under 2 irrigation conditions: drought and control. We used a convolutional neural network (CNN) as a model to estimate the phenotypic values of 5 conventional biomass-related traits: dry weight, main stem length, numbers of nodes and branches, and plant height. We utilized manually measured phenotypes of conventional traits along with RGB images and digital surface models from UAV remote sensing to train our CNN models. The accuracy of the developed models was assessed through 10-fold cross-validation, which demonstrated their ability to accurately estimate the phenotypes of all conventional traits simultaneously. Deep learning enabled us to extract features that exhibited strong correlations with the output (i.e., phenotypes of the target traits) and accurately estimate the values of the features from the input data. We considered the extracted low-dimensional features as phenotypes in the latent space and attempted to annotate them based on the phenotypes of conventional traits. Furthermore, we validated whether these low-dimensional latent features were genetically controlled by assessing the accuracy of genomic predictions. The results revealed the potential utility of these low-dimensional latent features in actual breeding scenarios.

DOI： 10.34133/plantphenomics.0244

Reaction norm for genomic prediction of plant growth: modeling drought stress response in soybean 査読有り

Yusuke Toda, Goshi Sasaki, Yoshihiro Ohmori, Yuji Yamasaki, Hirokazu Takahashi, Hideki Takanashi, Mai Tsuda, Hiromi Kajiya-Kanegae, Hisashi Tsujimoto, Akito Kaga, Masami Hirai, Mikio Nakazono, Toru Fujiwara, Hiroyoshi Iwata

2023年8月

出版者・発行元：Research Square Platform LLC

Abstract

Advances in high-throughput phenotyping technology have made it possible to obtain time-series plant growth data in field trials, enabling genotype-by-environment interaction (G×E) modeling of plant growth. Although the reaction norm is an effective method for quantitatively evaluating G×E and has been implemented in genomic prediction models, no reaction norm models have been applied to plant growth data. Here, we propose a novel reaction norm model for plant growth using spline and random forest models, in which daily growth is explained by environmental factors one day prior. The proposed model was applied to soybean canopy area and height to evaluate the influence of drought stress levels. Changes in the canopy area and height of 198 cultivars were measured by remote sensing using unmanned aerial vehicles. Multiple drought stress levels were set as treatments and their time-series soil moisture was measured. The models were evaluated using leave-one-environment-out cross-validation, in which a treatment-by-year combination was considered the environment. These results suggest that our model can capture G×E during the early growth, especially canopy height. Significant variations in the G×E of the canopy height during the early growth period were visualized using the estimated reaction norms. This result indicates the effectiveness of the proposed models on plant growth data and the possibility of revealing G×E in various growth stages in plant breeding by applying statistical or machine learning models to time-series phenotype data obtained with remote sensing.

DOI： 10.21203/rs.3.rs-3267332/v1

その他リンク： https://www.researchsquare.com/article/rs-3267332/v1.html

Triterpenoids in aerenchymatous phellem contribute to internal root aeration and waterlogging adaptability in soybeans. 国際誌 Open Access

Takahashi H, Abo C, Suzuki H, Romsuk J, Oi T, Yanagawa A, Gorai T, Tomisaki Y, Jitsui M, Shimamura S, Mori H, Kaga A, Ishimoto M, Seki H, Muranaka T, Nakazono M

The New phytologist 239 巻 ( 3 ) 頁： 936 - 948 2023年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：New Phytologist

Soybeans (Glycine max) develop newly differentiated aerenchymatous phellem (AP) in response to waterlogging stress. AP is formed in the hypocotyl and root, thus contributing to internal aeration and adaptation to waterlogging for several legumes. Extensive accumulation of triterpenoids – lupeol and betulinic acid – has been identified in AP. However, their physiological roles in plants remain unclarified. Lupeol is converted from 2,3-oxidosqualene by lupeol synthase (LUS) and oxidized to betulinic acid. Notably, soybeans have two LUS genes (GmLUS1 and GmLUS2). Functional analysis was performed to reveal the biological and physiological functions of triterpenoids in AP using lus mutants. The AP cells of lus1 mutant lacked triterpenoid accumulation and epicuticular wax. Lupeol and betulinic acid were the major components of epicuticular wax and contributed to tissue hydrophobicity and oxygen transport to the roots. Tissue porosity in AP was lower in the lus1 mutant than in the wild-type, which resulted in reduced oxygen transport to the roots via AP. This reduction in oxygen transport resulted in shallow root systems under waterlogged conditions. Triterpenoid accumulation in AP contributes to effective internal aeration and root development for adaptation to waterlogging, suggesting the significance of triterpenoids in improving waterlogging tolerance.

DOI： 10.1111/nph.18975

その他リンク： https://www.researchsquare.com/article/rs-2230730/v1.html

The barrier to radial oxygen loss protects roots against hydrogen sulphide intrusion and its toxic effect. 国際誌 Open Access

Peralta Ogorek LL, Takahashi H, Nakazono M, Pedersen O

The New phytologist 238 巻 ( 5 ) 頁： 1825 - 1837 2023年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：New Phytologist

The root barrier to radial O<inf>2</inf> loss (ROL) is a key root trait preventing O<inf>2</inf> loss from roots to anoxic soils, thereby enabling root growth into anoxic, flooded soils. We hypothesized that the ROL barrier can also prevent intrusion of hydrogen sulphide (H<inf>2</inf>S), a potent phytotoxin in flooded soils. Using H<inf>2</inf>S- and O<inf>2</inf>-sensitive microsensors, we measured the apparent permeance to H<inf>2</inf>S of rice roots, tested whether restricted H<inf>2</inf>S intrusion reduced its adverse effects on root respiration, and whether H<inf>2</inf>S could induce the formation of a ROL barrier. The ROL barrier reduced apparent permeance to H<inf>2</inf>S by almost 99%, greatly restricting H<inf>2</inf>S intrusion. The ROL barrier acted as a shield towards H<inf>2</inf>S; O<inf>2</inf> consumption in roots with a ROL barrier remained unaffected at high H<inf>2</inf>S concentration (500 μM), compared to a 67% decline in roots without a barrier. Importantly, low H<inf>2</inf>S concentrations induced the formation of a ROL barrier. In conclusion, the ROL barrier plays a key role in protecting against H<inf>2</inf>S intrusion, and H<inf>2</inf>S can act as an environmental signalling molecule for the induction of the barrier. This study demonstrates the multiple functions of the suberized/lignified outer part of the rice root beyond that of restricting ROL.

DOI： 10.1111/nph.18883

Post-embryonic function of GLOBULAR EMBRYO 4 (GLE4)/OsMPK6 in rice development. 査読有り Open Access

Ishimoto K, Nosaka-Takahashi M, Kishi-Kaboshi M, Watanabe T, Abe K, Shimizu-Sato S, Takahashi H, Nakazono M, Hirochika H, Sato Y

Plant biotechnology (Tokyo, Japan) 40 巻 ( 1 ) 頁： 9 - 13 2023年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：日本植物バイオテクノロジー学会

In plants, mitogen activated protein kinases (MPKs) are involved in various signaling pathways that lead to biotic and abiotic responses as well as that regulate developmental processes. Among them, MPK6 and its closely related homologue, MPK3, act redundantly and are known to be involved in asymmetric cell divisions of meristemoid mother cells in stomata development and of zygotes in Arabidopsis. Loss-of-function mutants of GLE4/OsMPK6, which is an orthologue of MPK6 in rice, showed a defect in polarity establishment in early stage of embryogenesis. However, because of the embryo lethality of the mutations, the function of GLE4/OsMPK6 in post-embryonic development is not clarified. Here, we report the analysis of post embryonic function of GLE4/OsMPK6 in vegetative stage of rice using regenerated gle4/osmpk6 homozygous plants from tissue culture. The regenerated plants are dwarf and produce multiple shoots with small leaves. These shoots never develop into reproductive stage, instead, proliferate vegetative shoots repeatedly. Leaves of gle4/osmpk6 have small leaf blade at the tip and blade-sheath boundary become obscure. Stomata arrangement is also disturbed in gle4/osmpk6 leaf blade. The shape of shoot apical meristem of gle4/osmpk6 become disorganized. Thus, GLE4/OsMPK6 functions in shoot organization and stomata patterning in the post embryonic development in rice.

DOI： 10.5511/plantbiotechnology.22.1117a

Random regression for modeling soybean plant response to irrigation changes using time-series multispectral data. 査読有り Open Access

Sakurai K, Toda Y, Hamazaki K, Ohmori Y, Yamasaki Y, Takahashi H, Takanashi H, Tsuda M, Tsujimoto H, Kaga A, Nakazono M, Fujiwara T, Iwata H

Frontiers in plant science 14 巻頁： 1201806 2023年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Frontiers in Plant Science

Plant response to drought is an important yield-related trait under abiotic stress, but the method for measuring and modeling plant responses in a time series has not been fully established. The objective of this study was to develop a method to measure and model plant response to irrigation changes using time-series multispectral (MS) data. We evaluated 178 soybean (Glycine max (L.) Merr.) accessions under three irrigation treatments at the Arid Land Research Center, Tottori University, Japan in 2019, 2020 and 2021. The irrigation treatments included W5: watering for 5 d followed by no watering 5 d, W10: watering for 10 d followed by no watering 10 d, D10: no watering for 10 d followed by watering 10 d, and D: no watering. To capture the plant responses to irrigation changes, time-series MS data were collected by unmanned aerial vehicle during the irrigation/non-irrigation switch of each irrigation treatment. We built a random regression model (RRM) for each of combination of treatment by year using the time-series MS data. To test the accuracy of the information captured by RRM, we evaluated the coefficient of variation (CV) of fresh shoot weight of all accessions under a total of nine different drought conditions as an indicator of plant’s stability under drought stresses. We built a genomic prediction model ( (Formula presented.) ) using the genetic random regression coefficients of RRM as secondary traits and evaluated the accuracy of each model for predicting CV. In 2020 and 2021,the mean prediction accuracies of (Formula presented.) built in the changing irrigation treatments (r = 0.44 and 0.49, respectively) were higher than that in the continuous drought treatment (r = 0.34 and 0.44, respectively) in the same year. When the CV was predicted using the (Formula presented.) across 2020 and 2021 in the changing irrigation treatment, the mean prediction accuracy (r = 0.46) was 42% higher than that of the simple genomic prediction model (r =0.32). The results suggest that this RRM method using the time-series MS data can effectively capture the genetic variation of plant response to drought.

DOI： 10.3389/fpls.2023.1201806

Asymmetric auxin distribution establishes a contrasting pattern of aerenchyma formation in the nodal roots of Zea nicaraguensis during gravistimulation. 査読有り Open Access

Ning J, Yamauchi T, Takahashi H, Omori F, Mano Y, Nakazono M

Frontiers in plant science 14 巻頁： 1133009 2023年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Frontiers in Plant Science

Auxin distribution is essential for determining root developmental patterns. The formation of lateral roots and constitutive aerenchyma, which is a gas space developed through cell death, is regulated by auxin in rice (Oryza sativa). However, it is unclear whether the involvement of auxin in constitutive aerenchyma formation is conserved in other species. In this study, we found that constitutive aerenchyma formation was regulated by auxin in the nodal roots of Zea nicaraguensis, a wild relative of maize (Zea mays ssp. mays) grown naturally on frequently flooded coastal plains. Subsequent gravistimulation (root rotation) experiments showed opposite patterns of aerenchyma and lateral root formation. Lateral root formation on the convex side of rotated roots is known to be stimulated by a transient increase in auxin level in the pericycle. We found that aerenchyma formation was accelerated in the cortex on the concave side of the rotated nodal roots of Z. nicaraguensis. A cortex-specific expression analysis of auxin-responsive genes suggested that the auxin level was higher on the concave side than on the convex side. These results suggest that asymmetric auxin distribution underlies the regulation of aerenchyma and lateral root formation in the nodal roots of Z. nicaraguensis. As aerenchyma reduces the respiratory cost of the roots, constitutive aerenchyma on the concave side of the nodal root may balance resource allocation, thereby contributing to the uptake of water and nutrients by newly formed lateral roots. Our study provides insights into auxin-dependent asymmetric root patterning such as that of gravistimulation and hydropatterning response.

DOI： 10.3389/fpls.2023.1133009