Plant tissue metagenomic sequencing
Bacterial canker, caused by Pseudomonas syringae pv. actinidiae (Psa), is a highly destructive disease affecting kiwifruit (Actinidia spp.), with its severity modulated by environmental conditions and host genetic background. Nevertheless, the interactions between bacterial canker and the plant microbiome remain poorly characterized. This study comparatively analyzed the rhizosphere and endophytic bacterial communities of two kiwifruit varieties, Actinidia chinensis 'Hongyang' (susceptible) and A. chinensis 'Hort16A' (resistant), in both healthy and diseased plants, using Illumina MiSeq sequencing. Additionally, fluorescence in situ hybridization (FISH) was employed to visualize the spatial distribution of key antagonistic bacteria within plant branches. Significant differences in bacterial community composition were observed between varieties and between health statuses within each variety. Dominant genera such as Pseudomonas, unclassified_f_Enterobacteriaceae, unclassified_o_Enterobacterales, Enterobacter, and Erwinia, exhibited distinct distribution patterns in 'Hongyang' and 'Hort16A'. Notably, healthy 'Hort16A' plants harbored a higher abundance of antagonistic bacteria, including Lactobacillus and Bifidobacterium, whereas 'Hongyang' and diseased plants showed increased proportions of Pseudomonas and Erwinia. These results indicate that bacterial canker infection restructures the endophytic bacterial community and suggest that specific beneficial taxa may underlie host resistance mechanisms. These insights provide a foundation for developing microbiome-based management strategies against bacterial canker.