Analysis of physiological and molecular mechanisms of cotton trichome aphid resistance based on SWS-1 mutant

Cotton is a globally significant cash crop; however, its production is frequently compromised by aphid infestations. This study systematically investigated the regulatory mechanisms governing aphid resistance through leaf trichome development. A comprehensive investigation, encompassing multi-omics analysis, genetic validation, and physiological-biochemical experiments, was conducted to determine the impact of trichome density on aphid resistance. The findings revealed that trichome density exceeding 701.4/cm² significantly enhances aphid resistance. This mechanism involves the creation of physical barriers to aphid feeding and the induction of defensive metabolite accumulation (e.g., β-caryophyllene and D-limonene). After aphid feeding, there was a significant increase in soluble sugar content and POD activity in the high-trichome lines. Subsequent analysis, employing both BSA-seq and transcriptomic techniques, has identified four key genes (GhABCG32, GhV6Z11, GhRSD1, and GhSHMT3). The functional validation experiment demonstrated that the silencing of the GhABCG32 gene via the VIGS (virus-induced gene silencing) technology resulted in a significant reduction in leaf trichomes and a substantial decrease in stem trichomes. This finding serves to confirm the critical role of this gene in trichome formation and aphid resistance. The present study provides theoretical foundations and key gene targets for molecular design breeding of high-yielding aphid-resistant cotton varieties.