Preeliminary screening of endophytic bacteria associated with rootsof potato plant grown in middle altitude as antagonist against bacterial wilt disease caused by Ralstonia solanacearum

Anotace: Bacterial wilt disease caused by Ralstonia solanacearum is a devastating plant disease on potato plant. This study aimed to screen endophytic bacteria isolated from potato roots planted in middle latitude areas and confirm their antagonistic potential against R. solanacearum. Endophytic bacteria were isolated from healthy potato roots (Granola cultivar) grown in the middle latitude area (500–700 m.a.s.l.) in Bumiaji Sub-District, Batu City, East Java, Indonesia. In this study, 130 endophytic bacteria were isolated. As a result, eight endophytic bacterial isolates were found as potential antagonists against potato wilt diseases (R. solanacearum) i.e., E1, E5, E6, E104, E117, E120, E121, and E129. Based on in vivo test, E1 isolate reduced the bacterial wilt disease in potato by 20.74% and significantly increased plant growth (plant height and plant dry weight). The ability of the endophytic bacteria to produce the antibiosis substance against the R. solanacearum and their ability to reduce bacterial wilt disease in vivo suggests that those bacterial isolates have the potency to be developed as the candidates for biocontrol agents against bacterial wilt disease caused by R. solanacearum. However, it is necessary to identify the molecular bacteria isolated in this study to determine which species can suppress wilt disease and increase the growth of potato plants.