Assistant Professor University of Texas Rio Grande Valley Edinburg, Texas
Body of Abstract: Sorghum [Sorghum bicolor (L.) Moench] is a major cereal crop in the world both in terms of acreage and production. In spite of its importance, not much is known about the post-transcriptional regulation in response to abiotic stresses in sorghum. Alternative polyadenylation (APA) regulates diverse developmental and physiological processes, by virtue of its effects on gene expression, mRNA stability, translatability, and transport. This study has undertaken a genome-wide APA analysis in sorghum seedlings, subjected to several abiotic stresses. Our study unveiled widespread occurrence of APA in response to different abiotic stresses. Our analysis revealed that in response to different abiotic stresses, the relative levels of mRNA isoforms derived from APA within protein-coding regions and 5΄UTRs increased significantly, whereas, the levels of isoforms with poly(A) sites within 3΄UTRs decreased significantly. Poly(A) sites mapped to unannotated regions of the genome increased significantly in response to stresses and majority of these sites mapped to potentially new unannotated transcriptional units. Remarkably, a novel sequence element was found to be associated with stress-induced APA within introns. Our analysis has also identified sets of PACs and underlying genes, those display APA in response to one or multiple stress treatment(s). Additionally, we have demonstrated considerable overlap between the genes affected by APA and genes differentially expressed between stress-treated and corresponding control samples, suggesting role of APA in regulating gene expression in response to abiotic stresses. Altogether, these results established a widespread role for APA in regulating abiotic stress responses in this important cereal and bioenergy crop.