Biocontrol of Fusarium Wilt and Growth Promotion of Tomato Plants Using Endophytic Bacteria Isolated from Solanum elaeagnifolium Stems

摘要

Seven culturable bacterial isolates, obtained from the internal stem tissues of Solanum elaeagnifolium and successfully colonizing the internal stem tissues of tomato cv. Rio Grande, were screened for their invivo antifungal activity against Fusarium oxysporum f.sp. lycopersici (FOL) and their growth-promoting potential on tomato plants. SV101 and SV104 isolates, assessed on pathogen-challenged tomato plants led to a significant decrease (77-83%) in Fusarium wilt severity and vascular browning extent (76%), as compared to the inoculated and untreated control. Isolates enhanced growth parameters on pathogen-challenged and unchallenged tomato plants. SV104 and SV101 isolates were most effective in suppressing disease and enhancing plant growth. These two isolates were identified as Bacillus sp. str. SV101 () and B.tequilensis str. SV104 (). They displayed antifungal activity against FOL; pathogen growth was inhibited by 64% and an inhibition zone (11.50 and 19.75mm) against FOL could be formed using whole cell suspensions. SV101 and SV104 extracellular metabolites also inhibited FOL growth by 20 and 55%, respectively, as compared to control. B.tequilensis str. SV104 was shown to produce protease, chitinase, pectinase, IAA and siderophores. Bacillus sp. str. SV101 displayed pectinase activity and was found to be an IAA-producing and phosphate-solubilizing agent. To our knowledge, this is the first study reporting on S.elaeagnifolium use as a potential source of potent biocontrol and plant growth-promoting agents.