Genome-Wide Identification and Proteomic Analysis of the Wheat ABCG Family Reveal a Pivotal Role of TaABCG7B-8 in Fertility Conversion of a Photoperiod-Temperature-Sensitive Genic Male Sterility Wheat

The ABCG subfamily is the largest branch of plant ATP-binding cassette (ABC) transporters and plays key roles in lipid, sterol, and sporopollenin transport, influencing plant reproduction and environmental adaptation. However, their functions in wheat, particularly in photoperiod-temperature-sensitive genic male sterility (PTGMS), remain poorly understood. Here, we identified 176 wheat ABCG genes and classified them into pleiotropic drug resistance and white-brown complex homologue clades, with polyploidization and gene duplication driving family expansion. Integrated proteomic and spatiotemporal expression analyses identified five other stage-specific ABCG proteins under contrasting fertility conditions. Promoter and miRNA analyses revealed enrichment of photothermal-responsive cis-elements and seven negatively associated miRNAs. Functional assays showed that silencing TaABCG7B-8 impaired anther and pollen development, resulting in male sterility, while transcriptomic analysis suggested its involvement in ABC transporter-related pathways during fertility conversion. These findings provide insights into ABCG-mediated fertility regulation and suggest the potential utility of TaABCG7B-8 in PTGMS-based hybrid wheat breeding.