Poster abstracts
Poster number 46 submitted by Guijie Hao
Drought Stress Changes Poly (A) Site Choice in Arabidopsis thaliana
Guijie Hao (Department of Plant and Soil Sciences, University of Kentucky), Arthur G. Hunt (Department of Plant and Soil Sciences, University of Kentucky)
Abstract:
mRNAs polyadenylation is an important step in eukaryotic gene expression. Polyadenylation impacts gene expression through determining the coding and regulation potential of the mRNA, especially mRNAs of genes that may be polyandenylated at more than one position. Alternative polyadenylation (APA) has potential effect to gene regulation and function. In Arabidopsis, APA may be linked with stress responses through a polyadenylation complex subunit (CPSF30) that is inhibited by calmodulin and by disulfide remodeling; calcium signaling (through calmodulin) and disulfide remodeling (through the generation of reactive oxygen species) are typically associated with various stress responses in plants, suggestive of a possible connection.
In order to explore this, a study was done to examine the effects that an artificial drought stress (triggered by growth of plants in mannitol) has on genome-wide poly (A) site choice. We treated wild type Arabidopsis with different concentrations of mannitol, for varying lengths of time. RNA was extracted after harvesting the whole seedlings and poly (A) tag libraries were prepared and sequenced on the Illumina platform. The sequence data was analyzed to assess gene expression and alternative polyadenylation. The gene expression analysis demonstrated genes from certain GO categories are up- or down- regulated by the simulated drought stress; these categories include responses to hormone stimulus, secondary metabolism, transmembrane transport, regulation of transcription, and protein phosphorylation. Moreover, the results showed that drought stress caused significant changes in the usage of poly (A) sites that lie within 5’-UTRs; specifically, the poly (A) site profiles for a number of genes were shifted to increased usage of sites within 5’ UTRs, site that would truncate the mRNA.
These results indicate that drought stress alters poly (A) site choice for many genes, and may play negative regulatory roles for genes that possess poly (A) sites that fall within 5’-UTRs. They also suggest that APA plays an important role in the responses of Arabidopsis to drought stress. Future studies will include 3’-RACE confirmation of selected genes, and comparisons of the effects of drought stress with other abiotic and biotic stresses.
Keywords: Alternative polyadenylation, drought, Arabidopsis thaliana