Understanding the Impact of Salt Stress on Plant Pathogens Through Phenotypic and Transcriptomic Analysis.

For plant diseases to become established, plant pathogens require not only virulence factors and susceptible hosts, but also optimal environmental conditions. The accumulation of high soil salinity can have serious impacts on agro-biological ecosystems. However, the interactions between plant pathogens and salinity have not been fully characterized. This study investigated the effects of salt stress on representative plant pathogens, such as , , subsp. (), , and pv. . Phenotypic assays revealed that and are highly sensitive to salt stress, exhibiting significant reductions in growth, motility, and enzyme production, whereas showed notable tolerance. Pan-genome-based comparative transcriptomics identified co-downregulated patterns in and under stress conditions, indicating the suppression of bacterial chemotaxis and type III secretion systems. Uniquely upregulated patterns in were associated with enhanced survival under high salinity, such as protein quality control, osmotic equilibrium, and iron acquisition. Additionally, the application of salt stress combined with the beneficial bacterium significantly reduced tomato wilt caused by , suggesting a potential management strategy. This study underscores practical implications for effectively understanding and controlling plant pathogens under future climate changes involving salt stress.