Characterization of Trichoderma isolates and assessment of antagonistic potential against Fusarium oxysporum f. sp. cumini

Abstract

Cumin wilt caused by Fusarium oxysporum f. sp. cumini is one of the most destructive diseases responsible for causing even up to 60 per cent yield losses in cumin belt of India. Due to the soil inhabiting and seed borne nature with aggressive sporulation ability of the pathogen, sustainable and effective management of this disease using cultural practices and chemical methods is tedious. However, the uses of resistant varieties as well as novel biocontrol agents offer more economic and environmental friendly method of management which can be integrated with regulated chemical methods to achieve maximum disease suppression. Therefore, in the present study Trichoderma spp. isolated from banana rhizosphere of wilt suppressive and salt affected soils of Uttar Pradesh were characterized using morphological and molecular methods. The isolates were evaluated for their antagonistic potential against the pathogen F. oxysporum f. sp. cumini through dual culture assay. Out of 21 Trichoderma isolates screened, three isolates viz., CSR-T-2, CSR-T-3 and CSR-T-4 showed significant inhibition of F. oxysporum f. sp. cumini with 62.65, 79.85 and 84.31 per cent inhibition, respectively. The three promising isolates were characterized morphologically on the basis of their colony characters on different culture media as well as microconidia size, setae, colour, hyphae, chlamydospores etc. The molecular identification for confirmation of. sp.cies status of these isolates were done by sequencing ribosomal RNA using ITS1 and ITS4 universal primers. The 3 isolates viz., CSR-T-2, CSR-T-3 and CSR-T-4 were identified as T. koningiopsis (KJ812401), T. reesei (MH997668) and T. asperellum (MN227242), respectively. In the present study the isolate CSR-T-4 identified as T. asperellum was found to be best in inhibiting the mycelia growth of cumin wilt pathogen under in-vitro conditions and thus can be further exploited for the biological management of cumin wilt under field conditions in form of bioformulation.