Project description:Arabidopsis BAK1/SERK3, a co-receptor of leucine-rich repeat pattern recognition receptors (PRR), mediates pattern-triggered immunity (PTI). Genetic inactivation of BAK1 or BAK1-interacting receptors (BIR) causes cell death. We foundthat the TIR-NBS-LRR protein CONSTITUTIVE SHADE-AVOIDANCE 1 (CSA1) physically interacts with BIR3, but not with BAK1 and mediates ETI-type cell death in the absence of BAK1 and BIR3.
Project description:DELLA proteins act as hubs that relay environmental information to the multiple transcriptional circuits that control growth and development through physical interaction with transcription factors from different families. We have analyzed the presence of one DELLA protein at the Arabidopsis genome by chromatin immunoprecipitation coupled to large-scale sequencing and we find that it binds at the promoters of multiple genes. Enrichment analysis shows a strong preference for cis elements recognized by specific transcription factor families. In particular, we demonstrate that DELLA proteins are recruited by type-B ARABIDOPSIS RESPONSE REGULATORS (ARR) to the promoters of cytokinin-regulated genes, where they act as transcriptional co-activators. The biological relevance of this mechanism is underpinned by the necessity of simultaneous presence of DELLAs and ARRs to restrict root meristem growth and to promote photomorphogenesis.
Project description:N-glycosylation is an important post-translational modification of proteins in all eukaryotes and involved in a number of diseases in mammalian systems. However, little is known about the role of protein N-glycosylation in plant defense responses to pathogen invasion. In the present study, we first identified glycoproteins related to systemic acquired resistance (SAR) in an Arabidopsis thaliana model using glycoproteomics platform based on high-resolution mass spectrometry. In total, 427 glycosylate sites corresponding to 391 glycopeptides and 273 unique glycoproteins were identified. A total of 65 significantly changed glycoproteins with 80 N-glycosylation were detected in systemic leaves of SAR-induced plants, including numerous GDSL-like lipases, thioglucoside glucohydrolases, kinases and glycosidases. A variety of significantly changed glycoproteins were involved in stomatal movement, and stomata aperture measurements further confirmed that stomata movement were regulated in systemic leaves of SAR-induced plants, suggesting that these proteins may be functionally involved in systemic stomatal immunity through glycosylation or deglycosylation. Functional enrichment analysis reveals that the significantly changed glycoproteins were mainly involved in N-glycan biosynthesis and degradation, phenylpropanoid biosynthesis, cutin and wax biosynthesis, plant-pathogen interactions. Comparative analysis of glycoproteomics data with proteomics and transcriptomics data suggest that these significantly changed glycoproteins were mainly regulated by post-translational modification during SAR. This study provides substantial insight into the role of protein glycosylation in SAR.