Isolation, characterization of endophytic bacteria and their biocontrol potential against early blight of tomato

摘要

Early blight caused by Alternaria solani is a predominant constraint which implicates major yield losses in tomato. A total of 24 isolates of endophytic bacteria were obtainedfrom different plant tissues including root, stem andfresh leaves of tomatoplants. All the bacterial isolates were testedfor the production of IAA, ammonia, HCN and siderophore. Further, the isolates were tested in vitro for their antagonistic activity against the causal organism of early blight in tomato, A. solani. The isolate EBT22 displayed maximum antifungal activity with an inhibition of62.66per cent. The five potential endophytic isolates were further testedfor their effect on plant growth parameters of tomato cv. Arka Vikas and the isolate EBT18 recorded highest germination (88.88%), root length (18.67 cm), shoot length (15. 91 cm) and vigour index (3302). The isolate EBT18 recorded minimum PDI of20.30 per cent when applied as seed treatment + soil drench with a per cent disease reduction of57.94 compared to control under glass house conditions. The isolates that were found to be highly effective were characterized on molecular basis by 16S rRNA gene sequencing and the most abundant genus of endophytic bacteria found are Bacillus sp.