Endophytic antagonize soil-borne fungal pathogens and suppress wilt complex disease in chickpea plants ( L.).

The present study aimed to identify potential endophytic bacteria antagonistic against three soil-borne fungal pathogens, and f.sp. causing root rot, collar rot, and fungal wilt diseases in chickpea plants, respectively. A total of 255 bacterial endophytes were isolated from the leaves, stems, and roots of seven different crop plants (chickpea, tomato, wheat, berseem, mustard, potato, and green pea). The dual culture-based screening for antifungal properties indicated that three endophytic isolates had strong inhibition (>50%) against all three pathogens tested. Based on morphological, biochemical, and molecular characterization, the selected isolates (TRO4, CLO5, and PLO3) were identified as different strains of . The bacterial endophytes (TRO4 and CLO5) were positive for plant growth promoting (PGP) traits , ammonia, siderophore, and indole-3-acetic acid (IAA) production. The bio-efficacy of the endophytes (TRO4, CLO5, and PLO3) was tested by an trial in chickpea pre-challenged with and f.sp. . The strains TRO4 and CLO5 were found to be effective in reducing percent disease incidence ( ≤ 0.05) and enhancing plant growth parameters. The different root parameters root length (mm), surface area (cm), root diameter (mm), and root volume (cm) were significantly (p ≤ 0.05) increased in TRO4 and CLO5 inoculated chickpea plants. Confocal Scanning Laser Microscopy showed heavy colonization of bacteria in the roots of endophyte-inoculated chickpea plants. The inoculation of endophytic strains TRO4 and CLO5 in chickpea plants through seed biopriming reduced the accumulation of superoxide, enhanced the plant defense enzymes, and induced the expression of Pathogenesis-Related (PR) genes. Semi-quantitative analysis of defense-related genes showed differential activation of PR genes ( and ) by endophyte inoculation. The results of the present study reveal the antagonistic potential of strains TRO4 and CLO5 against three major soil-borne fungal pathogens and their ability to suppress wilt complex disease in chickpea plants. This is the first report on the simultaneous suppression of three major soil-borne fungal pathogens causing wilt complex in chickpea plants by endophytic strains.