Expression of miRNAs of <i>Hevea brasiliensis</i> under drought stress is altered in clones with varying levels of drought tolerance

Abstract

MicroRNAs (miRNAs) in plants play critical role in regulating gene expression at the post-transcriptional level in a number of biological processes including plant growth, development and defense responses against biotic and abiotic stresses. Recent reports indicate the role of miRNAs in regulating genes associated with various metabolic as well as abiotic stress responsive pathways in <i>Hevea</i>. The present study was initiated with an objective to identify drought responsive miRNAs from <i>Hevea</i> and to elucidate their role in stress response/tolerance in four clones of <i>Hevea</i> with varying levels of drought tolerance. miRNAs were isolated from leaves of <i>Hevea</i> and annotated after sequencing. The selected miRNAs were quantified using real time PCR. Four of the miRNAs displayed definite pattern of expression. The miR164, miR167 and the novel miRNA (HbmiRn_42) were down regulated in susceptible clones. HbmiRn_42 got upregulated in tolerant clones, indicating its strong association with stress tolerance. On the contrary, miR482 was down regulated in tolerant clones, while there was no change in its expression level in susceptible clones. This study throws light on stress responsive miRNAs of <i>Hevea</i> and their regulation under drought conditions.