Heat Shock Transcription Factor GhHSFB2a Is Crucial for Cotton Resistance to .

Heat shock transcription factors (HSFs) play a critical regulatory role in many plant disease resistance pathways. However, the molecular mechanisms of cotton HSFs involved in resistance to the soil-borne fungus are limited. In our previous study, we identified numerous differentially expressed genes (DEGs) in the transcriptome and metabolome of -inoculated . In this study, we identified and functionally characterized , which is a DEG belonging to HSFs and related to cotton immunity to . Subsequently, the phylogenetic tree of the type two of the HSFB subfamily in different species was divided into two subgroups: and strawberry, which have the closest evolutionary relationship to cotton. We performed promoter cis-element analysis and showed that the defense-reaction-associated cis-acting element-FC-rich motif may be involved in the plant response to in cotton. The expression pattern analysis of displayed that it is transcriptional in roots, stems, and leaves and significantly higher at 12 h post-inoculation (hpi). Subcellular localization of GhHSFB2a was observed, and the results showed localization to the nucleus. Virus-induced gene silencing (VIGS) analysis exhibited that silencing increased the disease index and fungal biomass and attenuated resistance against . Transcriptome sequencing of wild-type and -silenced plants, followed by Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, protein-protein interaction, and validation of marker genes revealed that ABA, ethylene, linoleic acid, and phenylpropanoid pathways are involved in GhHSFB2a-mediated plant disease resistance. Ectopic overexpression of the gene in showed a significant increase in the disease resistance. Cumulatively, our results suggest that is required for the cotton immune response against -mediated ABA, ethylene, linoleic acid, and phenylpropanoid pathways, indicating its potential role in the molecular design breeding of plants.