P-083 - Effective seed treatment for bacterial fruit blotch in watermelon using Bacillus amyloliquefaciens PMB05 fermentation liquid and sodium silicate

Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a major limiting factor in watermelon production. Due to this being a seed-borne disease, disease management through seed treatments would be promising. Recent studies have demonstrated that the bacterial suspension of Bacillus amyloliquefaciens PMB05 enhance plant immune responses and reduce disease incidence and severity of BFB in watermelon. However, whether the BFB can be controlled by seed treatment of B. amyloliquefaciens PMB05 is still unknown. In this study, different seed treatment methods were evaluated to determine their influence on plant immunity and disease control. Seed treated with B. amyloliquefaciens PMB05 fermentation liquid (PMB05FL) treatment supplemented with 10% maltodextrin resulted in the highest bacterial population density and better disease control efficacy than the treatment with only B. amyloliquefaciens PMB05 powder. To enhance the protective effects of fermentation liquid, the addition of supplemental compounds was investigated. Since silicate might be a salicylic acid pathway activator, its impact with PMB05FL is worth being further studied. Result showed that sodium metasilicate improved the PMB05FL-intensified ROS generation rather than callose deposition in watermelon upon flg22_Ac activation. More importantly, the treatment of PMB05FL with sodium metasilicate effectively enhances biocontrol efficacy. We concluded that the seed coating of PMB05FL with sodium metasilicate exhibited superior disease control efficacy of BFB through plant immunity intensification.
Keyword:biocontrol