Glutamicibacter soli JF_198 stimulates the rhizosphere colonization of indigenous Paenibacillus sp. to suppress cucumber Fusarium

Introduction Beneficial microorganisms can facilitate the formation of advantageous microbial communities in the plant rhizosphere, thereby promoting plant health. Our research indicates that Glutamicibacter soli JF_198 can mitigate the severity of cucumber Fusarium wilt caused by Fusarium oxysporum f. sp. cucumerinum . This study investigates the tripartite association among Glutamicibacter soli JF_198, the cucumber rhizosphere microbiota, and cucumber Fusarium wilt suppression. Methods We evaluated JF_198-mediated disease suppression in cucumber pot experiments and analyzed rhizosphere bacterial communities by 16S rRNA amplicon sequencing. Rhizosphere transplantation, bacterial isolation, antagonistic screening, and growth, competition, and root colonization assays were performed to assess the role of candidate Paenibacillus isolates under cucumber root-exudate conditions. Results JF_198 treatment was associated with changes in selected rhizosphere bacterial taxa, particularly an increased trend in Paenibacillus -related taxa. Rhizosphere transplantation experiments showed that JF_198-associated rhizosphere microbiota could partially transfer disease-suppressive effects to sterile soil. We identified Paenibacillus -assigned OTU1077 as a candidate indigenous beneficial taxon showing increased relative abundance under JF_198 treatment. Further investigation suggested that JF_198 treatment was associated with enhanced Paenibacillus sp. colonization under root-exudate conditions. Discussion Our findings suggest that G. soli JF_198-mediated disease suppression under controlled pot conditions is associated with changes in selected rhizosphere bacterial taxa and increased relative abundance of indigenous biocontrol-associated bacteria. This study provides preliminary insights into microbiome-associated disease suppression under controlled pot conditions and may inform future development of microbial consortia, pending further validation under field conditions.