Lysinibacillus macroides stimulates systemic resistance against Potyvirus papayanuli in cucumber

Introduction New and potentially useful rhizobacterial isolates are the focus of the most ongoing research into phytoviruses management because of their ability to inhibit viral replication. Methods We investigated the efficacy of a newly-isolated strain of Lysinibacillus macroides in controlling Potyvirus papayanuli (papaya ring spot virus, PRSV) in cucumber plants. Results and discussion Significant changes were observed between the treatment and control groups. For instance, cucumber plants were shown to have less severe viral symptoms after being pre-treated with L. macroides and then inoculated with PRSV. Upon application of L. macroides soil drenching (SD) treatment, the disease severity rate decreased significantly by 78.3% and 71.5% at 2- and 3- weeks post-infection (WPI), respectively. Plants treated with L. macroides had a lower PRSV titer using ELISA. Moreover, in PRSV-infected cucumbers, L. macroides treatments significantly increased antioxidant enzymes production and defense gene expressions as compared to the control treatment. Therefore, it is possible that L. macroides induces systemic resistance in cucumber plants and adversely impacts PRSV development. As a sustainable and eco-friendly approach for PRSV management, our study is the first report on the antiphytoviral activity of L. macroides against PRSV.