Overexpression of gma-MIR394a confers tolerance to drought in transgenic Arabidopsis thaliana

MicroRNAs, key posttranscriptional regulators of eukaryotic gene expression, play important roles in plant development and response to stress. In this study, a soybean gma-MIR394a gene was functionally characterized, especially with regard to its role in drought stress resistance. Expression analysis revealed that gma-MIR394a was expressed differentially in various soybean tissues and was induced by drought, high salinity, low temperature stress, and abscisic acid treatment in leaves. One target gene of gma-miR394a, Glyma08g11030, was predicted and verified using a modified 5′ RLM-RACE (RNA ligase-mediated rapid amplification of 5′ cDNA ends) assay. Overexpression of gma-MIR394a resulted in plants with lowered leaf water loss and enhanced drought tolerance. Furthermore, overexpression of gma-MIR394a in Arabidopsis reduced the transcript of an F-box gene (At1g27340) containing a miR394 complementary target site. These results suggest that the gma-MIR394a gene functions in positive modulation of drought stress tolerance and has potential applications in molecular breeding to enhance drought tolerance in crops.

► Expression profiles and stress-responsive expression patterns of gma-miR394a in soybean. ► Overexpression of gma-MIR394a confers drought tolerance in Arabidopsis. ► Identification of the gma-miR394a targets. ► Repression of putative target genes by over-expression of gma-miRNA394a.