A Cotton Cyclin-Dependent Kinase E Confers Resistance to Verticillium dahliae Mediated by Jasmonate-Responsive Pathway

Abstract

Many subunits of the Mediator transcriptional co-activator complex are multifunctional proteins that regulate plant immunity in <i>Arabidopsis</i>. Cotton cyclin-dependent kinase E (GhCDKE), which is a subunit of the cotton (<i>Gossypium hirsutum</i>) Mediator complex, has been annotated, but the biological functions of this gene associated with regulating disease resistance have not been characterized. Here, we cloned <i>GhCDKE</i> from cotton and confirmed that GhCDKE belonged to the E-type CDK family in the phylogenetic tree, and, as in other eukaryotes, we found that GhCDKE interacted with C-type cyclin (GhCycC) by yeast two-hybrid and luciferase complementation imaging assays. Expression of <i>GhCDKE</i> in cotton was induced by <i>Verticillium dahliae</i> infection and MeJA treatment, and silencing of <i>GhCDKE</i> expression in cotton led to enhanced susceptibility to <i>V. dahliae</i>, while overexpression of <i>GhCDKE</i> in <i>Arabidopsis thaliana</i> enhanced resistance to this pathogen. Transgenic expression assay demonstrated that the transcriptional activity of <i>GhPDF1.2_pro:LUC</i> in <i>GhCDKE</i>-silenced cotton was dramatically inhibited. In addition, the expression of jasmonic acid (JA)-regulated pathogen-responsive genes was dramatically upregulated in <i>GhCDKE</i>-overexpressed plants after inoculation with <i>V. dahliae</i>, and the roots of <i>GhCDKE</i>-overexpressed <i>A. thaliana</i> were more susceptible to JA treatment. These results indicated that GhCDKE regulates resistance against <i>V. dahliae</i> and that this resistance is mediated by JA response pathway.