Multiomics Studies on the Effects of High-Temperature Stress on Male Sterility in Gossypium barbadense

High-temperature (HT) stress has been recognized as one of the main factors restricting the normal growth and development of cotton and severely affects fiber quality and yield. To elucidate the regulatory mechanism of male sterility-related hormones in Gossypium barbadense under HT stress, we explored candidate genes closely related to male sterility in G. barbadense. We studied the expression profiles of hormones and genes in the anthers of G. barbadense GB150 under HT stress by combining transcriptomic and metabolomic analyses. Through a combined analysis of the transcriptional metabolism of the anthers of G. barbadense GB150, we determined the contents of ABA, JA, SA, IAA, tZR, and GA₂₀ and the expression of genes related to biosynthetic pathways and signal transduction pathways. The results revealed that the ABA and JA contents significantly increased after HT; the IAA, tZR, and GA₂₀ contents significantly decreased; and the SA content did not significantly change after HT. We then used weighted gene coexpression network analysis (WGCNA) to further analyze the interactions among hormones, transcription factors, and core genes and constructed hormone coexpression networks and genome-wide coexpression networks. Through these network analyses, we ultimately identified 10 candidate genes closely related to male sterility in G. barbadense. Using qRT-PCR, resequencing data from 221 G. barbadense materials revealed that ALA4 (Arabidopsis thaliana has been proven to be associated with male fertility) and SBP1 (two stop gains in the gene structure) may play important roles in the process of male sterility in G. barbadense. The results of this study provide a theoretical basis for the molecular mechanism of male sterility in G. barbadense.