P-032.5 - Insight into the bacterial diversity of grapevine crown galls and shoots infected with Allorhizobium vitis in Japan

Grapevine crown gall (GCG) is a globally distributed and economically significant disease affecting grapevines. The causal agent of GCG is strains of Allorhizobium vitis that harbor a tumor-inducing plasmid (pTi). The microbial community within galls and infected shoots has not been extensively studied This study investigated the microbiota of gall and shoot tissues from infected vineyards in Japan. Amplicon sequencing using V3–V4 16S rRNA gene primers was conducted with the NextSeq 1000 sequencer, and operational taxonomic unit (OTU) clustering was performed using Qiime2 software. In grapevines exhibiting GCG symptoms, the average number of bacterial species in gall tissues (61.3, n = 4) was significantly higher than in shoots (34.0, n = 4), with A. vitis detected in both galls and shoot tissues. Moreover, the average number of bacterial species in grapevine shoots with GCG symptoms (35.9, n = 7) was significantly higher than in symptomless shoots (25.4, n = 12), suggesting that galled grapevines harbor greater bacterial diversity than healthy grapevines. Interestingly, A. vitis genes were detected in 5 out of 12 symptomless grapevines, indicating the presence of latent infections in these plants.