Water-saving irrigation suppresses on soil-crop pathogenicity: Insight on the co-host of virulence factors and antibiotic resistance genes.

Water-saving irrigation is increasingly being prioritized in agricultural production activities to conserve water resources and increase crop productivity. Yet, how water-saving irrigation affects soil-crop pathogenic, primarily involving in the prevalence of virulence factors (VFs) and antibiotic resistance genes (ARGs), remains unclear. Here we investigated the variations in the abundance of VFs and ARGs in the soil-crop system under different irrigation intensities, and explored the underlying mechanisms on suppressing the dissemination of ARGs and VFs. The results showed that irrigation intensities (50 %, 75 % and 100 % irrigation water, hereafter IW50, IW75 and IW100) did not significantly affect soil VFs and ARGs abundance, but was closely associated with their occurrences in roots and leaves. Water-saving irrigation (IW 50 and IW75) clearly reduced the proliferation of VFs and ARGs in crops, especially TEP, PhoP, basS, and evgS genes decreased by more than 80 % compared to recommended irrigation usage (IW100). And, the co-hosts largely contributed to the reduction of VFs and ARGs abundance. The network analysis demonstrated that the increase in negative interactions between co-hosts and non-cohosts after water-saving irrigation resulted in the decrease of co-hosts colonization. Further, the decline in HO-O, carbon and nitrogen metabolic functional genes indicated that water-saving irrigation can inhibit the microbial ability to utilize those resources, thus decreasing VFs and ARGs proliferation. Finally, we determined that IW75 was most beneficial for VFs and ARGs reduction and tomato production. The outcome deepened the understanding of suppression on the spread of VFs and ARGs by water-saving irrigation, thereby providing valuable guidance for sustainable water-efficient agricultural practices.