Project description:Drought stress can cause huge crop production losses. Drought resistance consists of complex traits, and is regulated by arrays of unclear networks at the molecular level. A stress-responsive NAC transcription factor gene SNAC1 has been reported for its function in the positive regulation of drought resistance in rice, and several downstream SNAC1 targets have been identified. However, a complete regulatory network mediated by SNAC1 in drought response remains unknown. In this study, we performed Chromatin immunoprecipitation sequencing (ChIP-Seq) and RNA-Seq of SNAC1-overexpression transgenic rice (SNAC1-OE) lines and wild-type under normal and moderate drought stress conditions, to identify all SNAC1 target genes at a genome-wide scale by RNA-Seq analyses. We detected 980 differentially expressed genes (DEGs) in the SNAC1-OE lines compared to the wild-type control under drought stress conditions. By ChIP-Seq analyses, we identified 4,339 SNAC1-binding genes under drought stress conditions (SNAC1BGDs). By combining the DEGs and SNAC1BGDs, we identified 93 SNAC1-targeted genes involved in drought responses (SNAC1TGDs). Most SNAC1TGDs are involved in transcriptional regulation, response to water loss, and other processes related to stress responses. Moreover, the major motifs in the SNAC1BGDs promoters include a NAC recognition sequence (NACRS) and an ABA responsive element (ABRE). SNAC1-OE lines are more sensitive to ABA than wild-type. SNAC1 can bind to the OsbZIP23 promoter, an important ABA signaling regulator, and positively regulate the expression of several ABA signaling genes.
Project description:The CAMTA1 mutant and Col-0 were studied under water and drought condition. The camta1 showed stunted primary root growth under osmotic stress. The expression analysis revealed drought recovery as major indicative pathway along with membrane and chloroplast related protein in camta1 under drought stress. Large number of positively regulated genes were related to osmotic balance, transporters, AP2 and ABA. We used Affymetrix expression analysis to validate the role of CAMTA1 under drought stress.
Project description:Histone H2B monoubiquitination (H2Bub1) has been implicated in several important physiological and developmental processes, but its role in the regulation of stress responses remains elusive. Here, we report that H2Bub1 is crucially involved in abscisic acid (ABA) signaling and drought response in rice. We found the rice (Oryza sativa) HISTONE MONOUBIQUITINATION2 (OsHUB2), an E3 ligase for H2Bub1, interacted with OsbZIP46, a key transcription factor regulating ABA signaling and drought response in rice. Genetic analyses suggest that OsHUB2, induced by drought and ABA, positively modulates ABA sensitivity and drought resistance. The H2Bub1 levels were increased in the promoters of OsbZIP46 target genes under the drought stress and ABA treatments, and the increased H2Bub1 levels were positively correlated to the increased expression levels of the target genes. Interestingly, MODD, a reported suppressor of ABA signaling and drought resistance through mediation of OsbZIP46 deactivation and degradation, can repress the H2Bub1 level in the promoters of OsbZIP46 target genes by recruiting a putative deubiquitinase OsOTLD1. Suppression of OsOTLD1 in vivo resulted in increased H2Bub1 levels and expression of drought-responsive genes targeted by OsbZIP46. These findings established an elaborate mechanism of histone monoubiquitination in the fine-turning of ABA signaling and drought response via balancing H2Bub1 deposition and removal.
Project description:Responses to drought in rice are regulated by transcription factor OsbZIP46 via ABA signaling. This work characterizes a protein MODD that negatively regulates OsbZIP46 activity and stability through HDAC-related chromatin remodeling and OsPUB70-mediated ubiquitination, respectively, to fine tune ABA signaling and drought resistance. Examination of mRNA levels in modd mutants and wild type plants under normal condition.
Project description:The CAMTA1 mutant and Col-0 were studied under water and drought condition. The camta1 showed stunted primary root growth under osmotic stress. The expression analysis revealed drought recovery as major indicative pathway along with membrane and chloroplast related protein in camta1 under drought stress. Large number of positively regulated genes were related to osmotic balance, transporters, AP2 and ABA. We used Affymetrix expression analysis to validate the role of CAMTA1 under drought stress. The RNA of Col-0 and camta1 mutant were isolated in water and drought condition.The ATH1 gene chip was used for expression analysis.
Project description:ABA INSENSITIVE 5 (ABI5) is a basic leucine zipper (bZIP) transcription factor which acts in the abscisic acid (ABA) signaling and is activated in response to abiotic stresses. It was shown that ABI5 binds ABA RESPONSIVE ELEMENTs (ABRE cis-elements) present in the promoters of regulated genes and activates or represses their transcription in response to stress. However, the precise role of barley (Hordeum vulgare) ABI5 in ABA signaling is still not well understood. We have identified a hvabi5.d mutant using barley TILLING (Targeted Induced Local Lesions IN Genomes) platform. hvabi5.d showed drought tolerant phenotype. To identify molecular mechanisms responsible for hvabi5.d response to drought, we perform drought-related gene expression analysis in barley in two genotypes: the wild-type (WT) barley cultivar 'Sebastian’ and hvabi5.d mutant; in two time points: (1) optimal water conditions, and (2) after 10 days of drought stress in the second leaf; analyses were performed in three biological replicates. Global transcriptome analysis (Agilent Barley Microarray) of the mutant and parent cultivar ‘Sebastian’ exposed to drought enabled to identify genes in hvabi5.d which were associated with better response of the mutant to drought. These data increase our understanding of HvABI5-dependent modulation of plant response to the drought stress.
Project description:Responses to drought in rice are regulated by transcription factor OsbZIP46 via ABA signaling. This work characterizes a protein MODD that negatively regulates OsbZIP46 activity and stability through HDAC-related chromatin remodeling and OsPUB70-mediated ubiquitination, respectively, to fine tune ABA signaling and drought resistance.
Project description:The urgent need to address water scarcity underscores the importance of enhancing plant drought resistance. This study investigates whether pretreatment with abscisic acid (ABA) activates early stress signaling, thereby improving barley drought response when subsequently exposed to drought conditions. Although the individual responses to drought and ABA are well-documented, their synergistic effects in barley warrant further investigation. This study examines the impact of ABA on barley drought resilience through an experimental design that incorporates four distinct treatments: optimal watering, ABA application at 60 days post-sowing, and two drought stress treatments - one with and the other without prior ABA application. Key physiological parameters, such as photosynthesis, stomatal conductance and chlorophyll content, were analyzed in conjunction with transcriptomics. The results suggest that ABA pretreatment initiates early stomatal closure and elevates the expression of essential genes like NCED1, BG8, and HvA22, priming barley for improved drought resistance. During the drought, ABA-pre-treated barley maintained high chlorophyll levels, indicating sustained photosynthetic activity, a trend that persisted across treatments during the post-drought recovery phase. Furthermore, ABA pre-treatment was found to preserve photosystem II efficiency during drought conditions. Transcriptomic analyses revealed distinct gene expression profiles, alternative splicing profile and isoform switching, highlighting the molecular complexities of ABA role in drought response. These alterations span stress response, metabolic pathways, and DNA modification processes, providing a comprehensive view of ABA treatment's regulatory and metabolic impacts. In conclusion, ABA pretreatment strengthens barley drought defense by fostering stomatal closure and gene activation, guiding research strategies grounded in ABA and suggesting that genotypes with elevated ABA levels could have enhanced resilience and recovery capabilities.
Project description:The OsbZIP23 transcription factor has been characterized for its essential role in drought resistance in rice, but the mechanism is unknown. Here, we performed genome-wide identification of OsbZIP23 targets by immunoprecipitation sequencing (ChIP-seq) and RNA Sequencing (RNA-Seq) analyses in the OsbZIP23-overexpression, osbzip23 mutant, and wild-type rice under normal and drought stress conditions. OsbZIP23 directly regulates a large number of reported genes that function in stress response, hormone signaling, and developmental processes. Among these targets, we found that OsbZIP23 could positively regulate OsPP2C49, and overexpression of OsPP2C49 in rice resulted in significantly decreased sensitivity of the ABA response and rapid dehydration. Moreover, OsNCED4 (9-cis-epoxycarotenoid dioxygenase 4), a key gene in ABA biosynthesis, was also positively regulated by OsbZIP23. Together, our results suggest that OsbZIP23 acts as a central regulator in ABA signaling and biosynthesis, and drought resistance in rice.