Receptor for Activated C Kinase1B (RACK1B) Delays Salinity-induced Senescence of Rice Leaves through Negative Regulation of Chlorophyll Degradation

• DOI: 10.20944/preprints202305.1946.v1
• Publication Date: 2023-05-29T02:18:12Z
• Authors: Md Ahasanur Rahman; Hemayet Ullah
• Keywords: Senescence; Ectopic expression

Abstract: The widely conserved RACK1 protein is a WD-40 type scaffold that regulates diverse environmental stress signal transduction pathways. Arabidopsis RACK1A has been reported to interact with various proteins in salt and Light-Harvesting Complex (LHC) However, the mechanism of how contributes photosystem chlorophyll metabolism conditions remains elusive. Using T-DNA-mediated activation tagging transgenic rice (Oryza sativa L.) lines, we show leaves from RACK1B gene (OsRACK1B) gain-of-function (RACK1B-OX) plants exhibit stay-green phenotype under salinity stress. In contrast, down-regulated OsRACK1B (RACK1B-UX) display an accelerated yellowing. qRT-PCR analysis revealed several genes encoding catabolic enzymes (CCEs) are differentially expressed both RACK1B-OX RACK1B-UX plants. addition CCEs, STAY-GREEN (SGR) key component forms SGR-CCE complex senescing chloroplasts, which causes LHCII instability. Transcript profiling significant upregulation OsSGR than during treatment. results imply senescence-associated transcription factors (TFs) altered accordance expression, indicating transcriptional reprogramming by novel regulatory involving OsRACK1B-OsSGR-TFs complex. Our findings suggest ectopic expression negatively degradation, leads steady level LHC-II isoform Lhcb1, essential prerequisite for state transition photosynthesis adaptation, delays salinity-induced senescence. Taken together, these provide important insights into molecular mechanisms senescence, can be useful circumventing effect on reducing yield penalty cereal crops, like rice, global climate change conditions.