MicroRNA expression profiles in response to drought stress in Sorghum bicolor.

The regulatory role of small non-coding RNAs that are 20-24 nucleotides in length has become the foremost area of research for biologists. A major class of small RNAs represented by the microRNAs (miRNAs), has been implicated in various aspects of plant development including leaf pattering, meristem function, root patterning etc. Recent findings support that miRNAs are regulated by drought and other abiotic stresses in various plant species. In this study, were report the expression profiling of 8 known abiotic stress deregulated miRNAs in 11 elite sorghum genotypes, under watered and drought conditions. Significant deregulation was observed with miR396, miR393, miR397-5p, miR166, miR167 and miR168. Among these, the expression levels of sbi-miR396 and sbi-miR398 were the highest in all the genotypes. The expression of sbi-miR396 was maximum in the grain sorghum HSD3226 under well-watered conditions and the profile shifted towards HSD3221 under drought stress. Forage accessions, N98 and Atlas, showed an opposite behavior in expression patterns of miR397-5p in drought physiologies. Such dynamic expression patterns could be indicative of prevailing drought tolerant mechanisms present in these sorghum accessions. This data provides insights into sorghum miRNAs which may have potential use in improving drought tolerance in sorghum and other cereal crops.