Language：English   Publishing type：Research paper (scientific journal)  

The shoot apical meristem (SAM) produces all above-ground organs of plants and is thus a central focus of plant developmental biology. Developmental processes in the SAM are regulated by various factors that control gene expression at the cellular level. Key among these are the chemical modifications of the N-terminal tails of histones, which are essential components of nucleosomes and chromatin that play crucial roles in these processes. While immunostaining is a valuable method for the spatial analysis of histone modifications, its application to the SAM has posed technical challenges. Here, we developed a three-dimensional immunostaining method for rice (Oryza sativa) SAMs at single-cell resolution using a permeabilization process with specific cell wall degrading enzymes, along with the iTOMEI clearing technique (Sakamoto et al. [2022] Communications Biology, 5, 12). We detected clear signals throughout the deeper tissue layers, allowing us to visualize histone modifications associated with both active and repressive chromatin states, as well as M phase-specific modifications localized on chromosomes. The repressive modifications H3K9me2 and H3K27me3 exhibited punctate patterns within the nuclei, whereas the modifications linked to transcriptional activity were more diffusely distributed. Double staining showed that H3K9me2 forms a peripheral layer around a central domain enriched in H3K4me1. A comparative analysis of SAMs during the vegetative and reproductive phases indicated that active modifications persisted across both phases, whereas repressive modifications increased during the reproductive phase. Our protocol facilitates the three-dimensional visualization of chromatin states in the SAM, offering a robust tool for exploring the spatial regulation of plant development at the single-cell level.

DOI： 10.1111/tpj.70470

Web of Science

Scopus

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Plants retain the ability to generate a pluripotent tissue called callus by dedifferentiating somatic cells. A pluripotent callus can also be artificially induced by culturing explants with hormone mixtures of auxin and cytokinin, and an entire body can then be regenerated from the callus. Here we identified a pluripotency-inducing small compound, PLU, that induces the formation of callus with tissue regeneration potency without the external application of either auxin or cytokinin. The PLU-induced callus expressed several marker genes related to pluripotency acquisition via lateral root initiation processes. PLU-induced callus formation required activation of the auxin signaling pathway though the amount of active auxin was reduced by PLU treatment. RNA-seq analysis and subsequent experiments revealed that Heat Shock Protein 90 (HSP90) mediates a significant part of the PLU-initiated early events. We also showed that HSP90-dependent induction of TRANSPORT INHIBITOR RESPONSE 1, an auxin receptor gene, is required for the callus formation by PLU. Collectively, this study provides a new tool for manipulating and investigating the induction of plant pluripotency from a different angle from the conventional method with the external application of hormone mixtures.

DOI： 10.3389/fpls.2023.1099587

Open Access

Web of Science

Scopus

PubMed

Language：English  

DOI： 10.1007/s11103-022-01271-y

PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

KEY MESSAGE: We characterized genes that function in the photoperiodic flowering pathway in cassava. Transcriptome analysis of field-grown plants revealed characteristic expression patterns of these genes, demonstrating that field-grown cassava experiences two distinct developmental transitions. Cassava is an important crop for both edible and industrial purposes. Cassava develops storage roots that accumulate starch, providing an important source of staple food in tropical regions. To facilitate cassava breeding, it is important to elucidate how flowering is controlled. Several important genes that control flowering time have been identified in model plants; however, comprehensive characterization of these genes in cassava is still lacking. In this study, we identified genes encoding central flowering time regulators and examined these sequences for the presence or absence of conserved motifs. We found that cassava shares conserved genes for the photoperiodic flowering pathway, including florigen, anti-florigen and its associated transcription factor (GIGANTEA, CONSTANS, FLOWERING LOCUS T, CENTRORADIALIS/TERMINAL FLOWER1 and FD) and florigen downstream genes (SUPRESSOR OF OVEREXPRESSION OF CONSTANS1 and APETALA1/FRUITFUL). We conducted RNA-seq analysis of field-grown cassava plants and characterized the expression of flowering control genes. Finally, from the transcriptome analysis we identified two distinct developmental transitions that occur in field-grown cassava.

DOI： 10.1007/s11103-021-01149-5

PubMed

Other Link： https://link.springer.com/article/10.1007/s11103-021-01149-5/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

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

PubMed

Other Link： http://link.springer.com/article/10.1007/s11103-020-01057-0/fulltext.html

J-GLOBAL

J-GLOBAL

Authorship：Lead author  

J-GLOBAL

J-GLOBAL