Project description:Rice (Oryza sativa L.) is one of the most important crops worldwide. In the field, rice always faces low humidity, salinity, or drought in various growth stages, which largely limit seedling growth, tillering, filling, and yield of rice. Here, we generated B RAF high-order mutants by CRISPR/Cas9 mediated genome editing. By RNA-seq analysis, we found rice B2 and B3 RAFs play central roles in osmotic stress responses, the mannitol-induced expression genes are largely impaired. Our findings uncovered the central role of B2 and B3 RAFs in rice's osmotic stress responses and ABA signaling.
Project description:Hyperosmotic stress caused by drought and salinity is a significant environmental threat that limits plant growth and agricultural productivity. Osmotic stress induces diverse responses in plants including Ca2+ signaling, accumulation of the stress hormone abscisic acid (ABA), reprogramming of gene expression, and altering growth. Despite intensive investigation, no global regulators of all of these responses have been identified. Here, we show that the Ca2+-responsive phospholipid binding BONZAI (BON) proteins are critical for all of these osmotic stress responses. A Ca2+-imaging-based forward genetic screen identified a loss-of-function bon1 mutant with a reduced cytosolic Ca2+ signal in response to hyperosmotic stress. The loss-of-function mutants of the BON1 gene family, bon1bon2bon3, are impaired in the induction of gene expression and ABA accumulation in response to osmotic stress. In addition, the bon mutants are hypersensitive to osmotic stress in growth inhibition. BON genes have been shown to negatively regulate plant immune responses mediated by intracellular immune receptor NLR genes including SNC1. We found that the defects of the bon mutants in osmotic stress responses were suppressed by mutations in the NLR gene SNC1 or the immunity regulator PAD4. Our findings indicate that NLR signaling represses osmotic stress responses and that BON proteins suppress NLR signaling to enable global osmotic stress responses in plants.
Project description:Nearly all of the transcript level responses to ABA in WT seedlings were diminished in the 112458 379101112 mutant. However, only a relatively small percentage of the transcript level responses to osmotic stress was abolished in the 112458 379101112 mutant, and the majority of the responses was maintained, although the levels of up- or down-regulation of many of the transcripts were reduced in the mutant.
Project description:Mitosis in early embryos often proceeds at a rapid pace, but how this pace is achieved is not understood. Here we show that cyclin B3 is the dominant driver of rapid embryonic mitoses in the C. elegans embryo. Cyclins B1 and B2 support slow mitosis (NEBD to Anaphase ~600s) but the presence of cyclin B3 dominantly drives the ~3-fold faster mitosis observed in wildtype. Multiple mitotic events are slowed down in Cyclin B1&B2-driven mitosis and cyclin B3-associated Cdk1 H1 kinase activity is ~25-fold more active than cyclin B1-associated Cdk1. Addition of cyclin B1 to fast cyclin B3-only mitosis introduces an ~60s delay between completion of chromosome alignment and anaphase onset; this delay, which is important for segregation fidelity, is dependent on inhibitory phosphorylation of the anaphase activator Cdc20. Thus, cyclin B3 dominance, coupled to a cyclin B1-dependent delay that acts via Cdc20 phosphorylation, sets the rapid pace and ensures mitotic fidelity in the early C. elegans embryo.
Project description:ced1 mutant has reduced expression of NCED3 in response to osmotic stress (polyethylene glycol) treatments compared to the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. We used microarrays to detail the global programme of gene expression under osmotic stress treatment and identified distinct classes of up/down-regulated genes in the stress pathway.
Project description:Multiple transcription factors (TFs) play essential roles in plants under abiotic stress, one of the most challenging conditions of plant survival. However, how these multiple TFs cooperate in abiotic stress responses still remains largely unknown. In this study, we provide evidence that a novel NAC (NAM, ATAF1/2, and CUC2) transcription factor (ANAC096) cooperates with bZIP-type TFs [ABRE-binding factor/ABRE-binding protein (ABF/AREB)] in ensuring survival under dehydration and osmotic stress conditions. Intriguingly, ANAC096 directly interacted with ABF2 and ABF4, but not with ABF3, both in vitro and in vivo. ANAC096 and ABF2 synergistically activated RD29A transcription. The genome-wide gene expression analysis revealed that a major proportion of ABA-responsive genes are under the transcriptional regulation of ANAC096.An Arabidopsis mutant, anac096, was hyposensitive to exogenous abscisic acid (ABA), and showed impaired ABA-induced stomatal closure and increased water loss under dehydration stress conditions. Furthermore, the anac096 abf2 abf4 triple mutant was much more sensitive to dehydration and osmotic stresses than the anac096 single mutant or the abf2 abf4 double-mutant. Based on these results, we propose that ANAC096 is involved in a synergistic relationship with a subset of ABFs for the transcriptional activation of ABA-inducible genes in response to dehydration and osmotic stresses.
Project description:m9 was identified to function in ABA signaling pathway and we applied RNAseq assay to identify ABA induced and repressed genes in m9
Project description:Multiple transcription factors (TFs) play essential roles in plants under abiotic stress, one of the most challenging conditions of plant survival. However, how these multiple TFs cooperate in abiotic stress responses still remains largely unknown. In this study, we provide evidence that a novel NAC (NAM, ATAF1/2, and CUC2) transcription factor (ANAC096) cooperates with bZIP-type TFs [ABRE-binding factor/ABRE-binding protein (ABF/AREB)] in ensuring survival under dehydration and osmotic stress conditions. Intriguingly, ANAC096 directly interacted with ABF2 and ABF4, but not with ABF3, both in vitro and in vivo. ANAC096 and ABF2 synergistically activated RD29A transcription. The genome-wide gene expression analysis revealed that a major proportion of ABA-responsive genes are under the transcriptional regulation of ANAC096.An Arabidopsis mutant, anac096, was hyposensitive to exogenous abscisic acid (ABA), and showed impaired ABA-induced stomatal closure and increased water loss under dehydration stress conditions. Furthermore, the anac096 abf2 abf4 triple mutant was much more sensitive to dehydration and osmotic stresses than the anac096 single mutant or the abf2 abf4 double-mutant. Based on these results, we propose that ANAC096 is involved in a synergistic relationship with a subset of ABFs for the transcriptional activation of ABA-inducible genes in response to dehydration and osmotic stresses. pTA plants (12-day-old) cultured in liquid medium were treated with 30 uM Dex alone for 1 h (Control) or 30 uM Dex alone for 30 min followed by an additional treatment of 30 min with both 30 uM Dex and 2 uM ABA (ABA). For pTA-ANAC096 plants, 12-day-old seedlings were treated with 30 uM Dex for 1 h (ANAC096) or with 30 uM Dex only for 0.5 h followed by additional 0.5 h incubation with both 2 uM ABA and 30 uM Dex (ANAC096+ABA). Total RNAs were isolated from two biological replicates at each condition and used to measure gene expression level.
Project description:ced2 mutant has reduced expression of NCED3 in response to osmotic stress (PEG, polyethylene glycol) treatments compared to the wild type. Other ABA biosynthesis genes are also greatly reduced in ced2 under osmotic stress. We used microarrays to detail the global programme of gene expression under osmotic stress treatment and identified distinct classes of up/down-regulated genes in the stress pathway.