Overexpression of miR1861h increases tolerance to salt stress in rice (Oryza sativa L.)

Salt stress is one of the most devastating abiotic stresses for global rice production. The conserved miR1861 family has been shown to participate in the control of plant growth, development, and response to abiotic stresses. However, no reports have focused yet on the roles of miR1861 in the salt stress responses. In a previous study, the member miR1861h was identified in Dongxiang wild rice (DXWR, Oryza rufipogon Griff.) with small RNA sequencing. In this study, we found that the expression level of miR1861h increased significantly under salt stress. Then, we generated transgenic plants overexpressing miR1861h under control of the CaMV35S promoter, and verified miR1861h expression using qRT-PCR analysis. We found that miR1861h overexpression increased plant salt stress tolerance significantly, as evidenced by higher survival rates. Analysis of putative targets and cis-acting elements further suggested that miR1861h could be a positive regulator of plant tolerance to salt stress. Taken together, our findings provide more insight into the roles of miR1861 family.