Susceptibility genes in plants: from molecular mechanisms to ecological implications for disease resistance

Susceptibility (S) genes serve as critical regulatory elements in plant-pathogen interactions and have been successfully targeted through genome editing approaches for disease resistance improvement in numerous crop species, achieving substantial progress across diverse agricultural systems. However, emerging evidence demonstrates that S genes simultaneously fulfill essential functions in plant development, physiological homeostasis, and environmental adaptation, reflecting their fundamental biological indispensability beyond pathogen susceptibility. This review synthesizes current knowledge of the functional classification, genome editing outcomes, and evolutionary significance of S genes, emphasizing that while targeted modification represents a powerful tool for resistance breeding, comprehensive understanding of their pleiotropic roles becomes increasingly important for optimizing breeding outcomes. We propose an integrative research framework that complements existing genome editing approaches by positioning S genes as dynamic regulatory interfaces within plant-environment networks, exploring complementary strategies for modulating S gene function through beneficial microbiome management, hormonal pathway optimization, and ecologically informed agricultural practices. This multidimensional approach may inform future crop protection strategies that integrate molecular precision with ecological sustainability.