Genome wide analysis of heat responsive microRNAs in banana during acquired thermo tolerance

Abstract

MicroRNAs are a class of small regulatory RNAs in plants, which play vital roles during various abiotic and abiotic stress conditions including plant processes. In this present study, we examined the expression of miRNAs and their predicted target expression levels during heat stress in banana. Out of 235 miRNA found in Musa, 40 miRNA showed homology to heat responsive miRNAs from other plants. Further, 14 targets for miRNA were predicted that are potentially regulated by their cognate miRNAs and were monitored under three stages of stress viz, induction, induction + lethal alone using qPCR analysis. The results suggest that generally, there is a negative relationship in the expression patterns of miRNA and their predicted cognate targets - HSP70, HSP90, SAP, DNAj genes. These were highly up regulated and their respective miRNAs showed lower expression. This is the first report in banana, which demonstrated that during induction stress, various thermo-protective genes are activated at initial stages of stress to achieve thermotolerance through altered miRNA expression. The results will help in broadening our understanding acquired thermotolerance and their regulation by miRNAs in plants.