Bacillus subtilis QST 713 Confers Protection to Tomato Plants Against Pseudomonas syringae pv tomato and Induces Plant Defence-related Genes

摘要

Bacterial speck, caused by Pseudomonas syringae pv. tomato (Pst), is an economically important disease of tomato, resulting in yield loss of marketable fruit. Management of bacterial speck is a challenge in commercial production fields due to the limited efficacy of current disease management strategies, as the pathogen acquires resistance to antibiotics and fixed copper bactericides and host resistance has not proven durable. Therefore, it is essential to develop alternative disease management strategies, like biological control. In this study, the efficacy of the commercially available biocontrol agent Bacillus subtilis QST 713 along with copper hydroxide was tested against Pst under greenhouse conditions. QST 713 reduced significantly disease severity and incidence compared to control and the copper hydroxide treatment; subsequently, the Pst population was lower in the QST 713-treated plants compared to control. In parallel, QST 713 and copper hydroxide increased plant height compared to control and mock plants. Furthermore, the quantitative PCR analysis of PR1a, PR1b and Pin2 expression suggests a positive role for Pin2 in the plant protective activity of QST 713, as Pin2 expression was significantly higher in the QST 713-treated plants challenged with Pst compared to the control Pst-inoculated plants.