PhD candidate King Abdullah University of Science and Technology Thuwal, Jeddah, Makkah, Saudi Arabia
Body of Abstract: Plants employ sophisticated molecular machinery to fine-tune their responses to growth, developmental, and stress cues. Gene expression influences the plant cellular responses through regulatory processes like transcription and splicing. Pre-mRNA is alternatively spliced to increase the genome coding potential and further regulate the expression. Serine/Arginine-rich (SR) proteins, a family of pre-mRNA splicing factors, recognize splicing cis-elements and regulate both constitutive and alternative splicing. Several studies reported SR protein genes in rice genome that are further subdivided into six subfamilies based on their domain structures. Here, we identified a new rice splicing factor with SR-dipeptides and grouped to the SR proteins, subfamily SC. OsSC106 (LOC_Os01g01150) regulates pre-mRNA splicing under abiotic stress conditions. OsSC106 localizes to the nuclear speckles, a major site for pre-mRNA splicing in the cell. Loss-of-function sc106 mutant is hypersensitive to salt, ABA, and low-temperature stress and shows developmental abnormality indicated by shorter length of shoot and root compared to WT seedling. The hypersensitivity to stress phenotypes was rescued by complementation using OsSC106 fused behind its endogenous promoter. Global gene expression and genome-wide splicing analysis in wild-type and sc106 seedlings revealed that OsSC106 regulates its targets, presumably through regulating alternative 3´ splice site. Under salt stress conditions, we identified multiple splice isoforms that are regulated by OsSC106. Collectively, our results suggest that OsSC106 is an important splicing factor that plays a crucial role for accurate pre-mRNA splicing and regulates development and abiotic stress responses in plants.
