Identification of microRNAs that are differentially expressed in drought and As stressed rice

We have characterized the changes in miRNA expression profiles in rice leaves under drought stress and As stress and compared these to unstressed leaves. 10 pairs of drought responsive and 8 pairs of As responsive miRNA-gene were identified and validated by qRT-PCR. This study identifies putative specific miRNA-mRNA regulatory modules with roles during drought and As stress. Putative microRNAs identified in this study are involved in hormone signaling, lipid and carbohydrate metabolism, and antioxidant defence. The results of this study will assist in elucidating the role of miRNAs in post-transcriptional regulation of target genes during abiotic stress and may contribute to the development of strategies to engineer drought and heavy metal resistance. Expression profiles in 4-week-old rice leaves dehydrated by 20% polyethylene glycol for 48 hours was compared with that in untreated control with three biological replicates.Expression profiles in 4-week-old rice leaves stressed by 10 mM As(III) solution (NaAsO2) and 50 mM As(V) solution (Na2HAsO4) for seven days was compared with that in untreated control with three biological replicates.