ABSTRACT

Fusarium wilt is one of the most consequential diseases affecting chickpea yield in India, which is caused by Fusarium oxysporum f. sp. ciceri (Foc). Endophytes are among the promising plant growth-promoting and biocontrol potential microbes. Bacterial endophytes can be defined as those bacteria that colonize the internal tissue of the plant showing no external sign of infection or negative effect on their host. In the present investigation, screening of advanced breeding lines against chickpea wilt, isolation and characterization of bacterial endophytes, in vitro evaluation of endophytes against Foc, effect of seed treatment with bacterial endophytes for the management of wilt disease in sick pots and growth promotion by bacterial endophytes were studied.
Screening of 70 advanced breeding lines against chickpea wilt resulted in 13 resistant lines. A total of 16 bacterial endophytic isolates were isolated from chickpea. Morphological characterization revealed that the colony colour of isolates varied from light white to creamy white. Biochemical tests revealed that, all the isolates were gram positive and showed positive result for H2S production, gelatin liquefaction, catalase test, oxidase test and negative result for indole production test. Based on molecular characterization, one strain each of Bacillus mojavensis, B. zhangzhouensis, B. velezensis, B. pumilus, B. safensis, B. licheniformis, Lysinibacilllus fusiformis, two strains of B. tequilensis, three strains of B. cereus and four strains of B. subtilis were identified.
In vitro evaluation of bacterial endophytes against Foc revealed that, maximum growth inhibition of Foc was by B. subtilis CBE15 (70.33%) followed by B. subtilis CBE14 (65.57%) and B. safensis CBE11 (60.95%), respectively. Seed treatment with bacterial endophytes B. subtilis CBE15 + B. subtilis CBE14 + B. tequilensis CBE11 (10 g/kg of seeds) recorded minimum wilt incidence of 6.67 per cent. Growth promotional potential of these bacterial endophytes was also established in pot culture experiments.