Integrative Analysis of Expression Profiles of mRNA and MicroRNA Provides Insights of Cotton Response to Verticillium dahliae .

Cotton Verticillium wilt, caused by the notorious fungal phytopathogen Verticillium dahliae ( V.   dahliae ), is a destructive soil-borne vascular disease and severely decreases cotton yield and quality worldwide. Transcriptional and post-transcriptional regulation of genes responsive to V.   dahliae are crucial for V.   dahliae tolerance in plants. However, the specific microRNAs (miRNAs) and the miRNA/target gene crosstalk involved in cotton resistance to Verticillium wilt remain largely limited. To investigate the roles of regulatory RNAs under V.   dahliae induction in upland cotton, mRNA and small RNA libraries were constructed from mocked and infected roots of two upland cotton cultivars with the V.   dahliae -sensitive cultivar Jimian 11 (J11) and the V.   dahliae -tolerant cultivar Zhongzhimian 2 (Z2). A comparative transcriptome analysis revealed 8330 transcripts were differentially expressed under V.   dahliae stress and associated with several specific biological processes. Moreover, small RNA sequencing identified a total of 383 miRNAs, including 330 unique conserved miRNAs and 53 novel miRNAs. Analysis of the regulatory network involved in the response to V.   dahliae stress revealed 31 differentially expressed miRNA-mRNA pairs, and the up-regulation of GhmiR395 and down-regulation of GhmiR165 were possibly involved in the response to V. dahliae by regulating sulfur assimilation through the GhmiR395- APS1/3 module and the establishment of the vascular pattern and secondary cell wall formation through GhmiR165- REV module, respectively. The integrative analysis of mRNA and miRNA expression profiles from upland cotton lays the foundation for further investigation of regulatory mechanisms of resistance to Verticillium wilt in cotton and other crops.