Cotton Mediates Plant Resistance against by miR482b Regulation.

Cotton Verticillium wilt, mainly caused by , has a serious impact on the yield and quality of cotton fiber. Many microRNAs (miRNAs) have been identified to participate in plant resistance to . infection, but the exploration of miRNA's function mechanism in plant defense is needed. Here, we demonstrate that the ghr-miR482b- module mediates cotton plant resistance to . infection. Based on the mRNA degradation data and GUS fusion experiments, ghr-miR482b directedly bonds to mRNA to lead to its degradation. The knockdown and overexpression of ghr-miR482b through virus-induced gene silencing strategies enhanced (decreased by 0.39-fold in disease index compared with the control) and weakened (increased by 0.46-fold) the plant resistance to . , respectively. In addition, silencing significantly increased (increased by 0.93-fold in disease index) the plant sensitivity to . compared with the control plants treated with empty vector. The expression levels of two SA-related disease genes, and , significantly decreased in -silenced plants by 0.71 and 0.67 times, respectively, and in ghr-miR482b-overexpressed (OX) plants by 0.59 and 0.75 times, respectively, compared with the control, whereas the expression levels of and were significantly increased by 1.21 and 2.59 times, respectively, in ghr-miR482b knockdown (KD) plants. In sum, the ghr-miR482b- module participates in the regulation of plant defense against . by inducing the expression of and genes.