Isolation and identification of grapevine endophytic bacteria with antagonistic potential against Fomitiporia mediterranea , a pathogen involved in grapevine trunk disease

Background Grapevine trunk diseases (GTDs) are an economically serious threat, affecting grapevine long-term sustainability and productivity. The use of antagonistic endophytic bacteria can be a promissing approach for GTDs’ management. Results 253 bacterial endophytes were isolated from the stems and roots of grapevines from 68 geographic locations in eight provinces of Iran. Based on biochemical properties, 22 strains were selected and identified using the 16S rRNA gene. The representative strains belonged to 13 genera of Agrobacterium , Arthrobacter , Bacillus , Chryseobacterium , Klebsiella , Kocuria , Pantoea , Pseudomonas , Rahnella , Rothia , Serratia , Staphylococcus and Variovorax . Using the dual culture method, antagonistic activity of 27 strains from 50 selected ones was shown against Fomitiporia mediterranea , a pathogen of GTDs; in which its hyphal growth was inhibited from 10 to 55%. Among the tested bacteria, Serratia plymuthica GI154, Bacillus sp. GI298 and Pseudomonas fluorescens GI310 showed the highest fungal growth inhibition zones, respectively. Co-treatment of GI154, GI298, and GI310 with F. mediterranea , in planta , could reduce the length of its internal canker by 54.41, 60.16 and 49.42% in compare with contol, respectively. Conclusions To the best of our knowledge, this is the first report of isolation of Arthrobacter agilis , Chryseobacterium daecheongense , Rahnella aquatilis , Serratia plymuthica , Staphylococcus epidermidis , Staphylococcus warneri and Variovorax paradoxus from grapevine in Iran. Moreover, this is the first report of Rothia amarae as a bacterial endophyte of the grapevine for the world. Grapevine bacterial endophytes exhibit auspicious biocontrol activities that can be utilized in sustainable and organic agriculture.