黄瓜韧皮部核心细菌群落结构及其功能解析OA

Plant endophytic microorganisms play a crucial role in regulating host nutrient absorption and stress resistance.However,the mechanisms by which host genetic factors drive the formation of specific microbial communities remain unclear.This study investigated cucumber,a model crop with a vascular system,focusing on the phloem-a key site for assimilate transport.Using 16S rRNA amplicon sequencing,we systematically analyzed the composition characteristics of endophytic bacterial communities in phloem tissues across different cucumber genotypes.Results showed that Proteobacteria dominated the phloem bacterial communities in all genotypes.Thirteen core amplicon sequence variants(ASVs)were identified,with culturable strains successfully isolated.Genome-wide association study(GWAS)revealed that the relative abundance of core ASV Stenotrophomonas_ASV1 showed significant association with SNP locus Chr4_24 974 285.The corresponding gene CsaV3_4G035400,encoding a xylanase-active protein,was identified as a potential key regulator of microbial recruitment.Functional validation demonstrated that this bacterial strain significantly promotes cucumber seedling growth.Our findings highlight the potential role of plant xylanase-related genes in regulating specific endophyte recruitment,providing new insights into host gene-microbe interaction mechanisms.