The Co-Association of Enterobacteriaceae and with Specific Resistant Cucumber against Wilt Disease.

The root microbiota contributes to the plant's defense against stresses and pathogens. However, the co-association pattern of functional bacteria that improves plant resistance has not been interpreted clearly. Using Illumina high-throughput sequencing technology, the root bacterial community profiles of six cucumber cultivars with different resistance in response to the causative agent of cucumber wilt (CFW), f. sp. (), were analyzed. The principal coordinate analysis indicated that the interactions of the cultivars and pathogens drove the cucumber root bacterial communities ( = 0.001). The resistance-specific differential genera across the cultivars were identified, including in the resistant cultivars, unclassified Enterobacteriaceae in resistant CL11 and JY409, in JY409, in moderately resistant ZN106, and unclassified Rhizobiaceae and in susceptible ZN6. The predominant root bacterium accounted for the relative abundance of up to 28.08-61.55%, but dramatically declined to 9.36% in -inoculated susceptible ZN6. ASV103 and ASV48 of Pseudomonadaceae and ASV162 of Enterobacteriaceae were consistently differential across the cultivars at the phylum, genus, and ASV levels. Using the culture-based method, antagonistic strains of Enterobacteriaceae with a high proportion of 51% were isolated. Furthermore, the bacterial complexes of E318 + Ps213 and spp. C1 + C7 reduced the disease index of CFW by 77.2% and 60.0% in the pot experiment, respectively. This study reveals the co-association of specific root bacteria with host plants and reveals insight into the suppressing mechanism of resistant cultivars against CFW disease by regulating the root microbiota.