Comparative analysis of microRNAs and their targets in the roots of two cultivars with contrasting salt tolerance in rice (Oryza sativa L.)

MicroRNAs (miRNAs) are small, non-coding RNAs that play essential roles in plant growth, development, and stress responses. Rice cultivars IR26 (sub. xian) and Jiucaiqing (sub. geng) exhibit significant salt tolerance differences during their growth. This study performed a genome-wide discovery of salt responsive miRNAs in rice roots, and in particular, the differentially expressed miRNAs between two cultivars. Specifically- and commonly-regulated miRNAs involved in salt stress between two cultivars were identified. The genes targeted by these miRNAs were involved in multiple biological processes including transcriptional regulation and response to stimulus. This preliminary characterization provides a framework for future analysis of miRNAs and their roles in rice salt stress response and describes the possible mechanisms for miRNA mediated salt tolerance by comparative analysis of miRNAs and their targets in salt-resistant and -sensitive cultivars.