Project description:The maintenance of stem cells within root meristem is the foundation for continuous growth of the root system. The PLETHORA (PLT) transcription factors have a function to control patterning of root stem cell niche, but the mechanism by which PLTs regulate root meristem activity remains unclear. In this work we show that rice PLT3, PLT4 and PLT5 function redundantly to maintain the stem cell pool of root meristem by repressing the expression of cell growth/development-promoting genes, which display a bivalent histone methylation feature marked by both H3K27me3 and H3K4me3 in root meristem cells. Mass spectrometry and protein interaction assays revealed that PLT5 could interact with core components of Polycomb Repressive Complex 2 (PRC2) that deposits H3K27me3 and the H3K4me3 demethylase JMJ703 in rice cells. In addition, JMJ703 could also interact with the PRC2 catalytic subunit SDG718. Loss of function of PLT3, PLT4 and PLT5 resulted in decreased H3K27me3, increased H3K4me3, and reduced PRC2 binding in bivalent genes in root meristem. Importantly we show that PLT5, PRC2 and JMJ703 could form a tripartite complex within nuclear condensates likely through PTL5 and/or JMJ703-induced phase-separation. These results uncover a chromatin mechanism by which PLTs control the patterning of stem cell niche in rice root meristem.
Project description:Magnaporthe oryzae (rice blast) and the root-knot nematode Meloidogyne graminicola are causing two of the most important pathogenic diseases jeopardizing rice production. Here, we show that root-knot nematode infestation on rice roots leads to important above-ground changes in plant immunity gene expression, which is correlated with significantly enhanced susceptibility to blast disease.
Project description:Rice MERISTEM ACTIVITYLESS1 (MAL1) is an RING-H2 finger domain (RFD) contained gene. To elucidate the molecular functions of MAL1 during crown root development, we generated MAL1 knock-down transgenic plants. MAL1 RNA interfering (RNAi) transgenic plants exhibited shorter crown root length and less crown root number phenotype accompanied by low cell division rate.Here we sought to find the downstream genes of OsMAL1 in rice crown root tip
Project description:Shoot-borne crown roots are the major root system in cereals. Previous work has shown that the Wuschel-related homeobox gene WOX11 is necessary and sufficient to promote rice crown root emergence and elongation. Here, we show that WOX11 recruits the ADA2-GCN5 histone acetyltransferase (HAT) module to activate downstream target genes in crown root meristem. OsGCN5 and OsADA2 are highly expressed in root meristem. Knockdown of OsGCN5 and OsADA2 affects crown root initiation and elongation. Here we sought to find the downstream genes of OsGCN5 in rice crown root tip.
Project description:Detailed analysis of genome-wide transcriptome profiling in rice root is reported here, following Cr-plant interaction. Such studies are important for the identification of genes responsible for tolerance, accumulation and defense response in plants with respect to Cr stress. Rice root metabolome analysis was also carried out to relate differential transcriptome data to biological processes affected by Cr (VI) stress in rice.
Project description:There are two main types of root systems in flowering plants, which are taproot systems in dicot and fibrous root systems in monocot. The cellular and molecular mechanism involved in root development are mainly from the study of dicot model Arabidopsis thaliana. However, mechanisms of root development and their conservation and divergence in monocot, which including the major crops, remain largely elusive. Here we profile the transcriptomes of more than 20,000 single cells in the root tips of two rice cultivars, Nipponbare (Nip; Japonica) and 93-11 (Indica). Single-cell analysis coupled with in situ hybridization identify the cell type-specific marker genes and annotate all the clusters. Comparison of single-cell transcriptome and analysis of mark gene expression suggest well-conserved molecular landscape between rice Nip and 93-11. Moreover, our analysis suggests specific functions gene expression patterns for each cell type cluster, including the hormone genes. Comparison to Arabidopsis single-cell RNA-sequencing dataset reveals extensive differences between Arabidopsis and rice cell types, and species-specific features emphasize the importance of directly studying rice root. Our study reveals transcriptome landscape of major cell types of rice root in singe-cell resolution and provides molecular insight of the cell type morphology of cell type evolution in plants.
Project description:There are two main types of root systems in flowering plants, which are taproot systems in dicot and fibrous root systems in monocot. The cellular and molecular mechanism involved in root development are mainly from the study of dicot model Arabidopsis thaliana. However, mechanisms of root development and their conservation and divergence in monocot, which including the major crops, remain largely elusive. Here we profile the transcriptomes of more than 20,000 single cells in the root tips of two rice cultivars, Nipponbare (Nip; Japonica) and 93-11 (Indica). Single-cell analysis coupled with in situ hybridization identify the cell type-specific marker genes and annotate all the clusters. Comparison of single-cell transcriptome and analysis of mark gene expression suggest well-conserved molecular landscape between rice Nip and 93-11. Moreover, our analysis suggests specific functions gene expression patterns for each cell type cluster, including the hormone genes. Comparison to Arabidopsis single-cell RNA-sequencing dataset reveals extensive differences between Arabidopsis and rice cell types, and species-specific features emphasize the importance of directly studying rice root. Our study reveals transcriptome landscape of major cell types of rice root in singe-cell resolution and provides molecular insight of the cell type morphology of cell type evolution in plants.
Project description:To elucidate the epigenetic regulation of salt-responsive genes helps to understand the underlying mechanisms that confer salt tolerance in rice. However, it is still largely unknown how epigenetic mechanisms function in regulating the salt-responsive genes in rice and other crops at a global level. In this study, we mainly focused on dynamic changes in transcriptome and histone marks between rice leaf and root tissues during salt treatment by using RNA-seq and ChIP-seq approaches. We demonstrated that the majority of salt-related differentially expressed genes (DEGs) display tissue-dependent changes. Similarly, tissue-dependent chromatin changes have been detected between leaf and root tissues during salt treatment. Most importantly, our study indicates that chromatin states with a combination of marks, rather than an individual mark, most likely play crucial roles in regulating differential expression of salt-responsive genes between leaf and root tissues. Especially, a special CS containing bivalent marks, H3K4me3 and H3K27me3 with a functional exclusion with each other, displays distinct functions in regulating expression of DEGs between leaf and root tissues, H3K27me3-related repressive mark mainly regulates expression of DEGs in root, but H3K4me3-releated active mark dominantly functions in regulation of down-regulated genes and possibly antagonize the repressive role of H3K27me3 in up-regulated genes in leaf. Thus, our findings indicate salt-responsive genes are differentially regulated at the chromatin level between the leaf and root tissues in rice, which provides new insights in the understanding of chromatin-based epigenetic mechanisms that confer salt tolerance in plants.
Project description:Contrary to the relative wealth of information regarding pathogen defense responses in aboveground plant parts, little is known about the mechanistic basis and regulation of plant immunity in root tissues. Aiming to further our fundamental understanding of root immune responses, we have investigated the interaction between rice and one of its major root pathogens, the oomycete Pythium graminicola. The specificic objectives of this study were twofold: i) to disentangle the molecular and genetic basis of the rice-Pythium interaction by comparing the transcriptome of rice roots at different times after inoculation with a highly virulent Pythium strains, and ii) to offer fundamental insights into the genetic architecture and regulation of rice disease resistance pathways operative in root tissue and to identify the molecular players controlling the possible nodes of convergence between these resistance conduits