Multitudinous Potential of Trichoderma Species in Imparting Resistance Against F. oxysporum f. sp. cucumerinum and Meloidogyne incognita Disease Complex

Abstract

Trichoderma spp. effectively inhibited mycelial growth of Fusarium oxysporum f. sp. cucumerinum F1, egg hatchability and juvenile mobility of M. incognita. Field emission scanning electron microscope (FESEM) studies revealed that Trichoderma koningiopsis TRI 41 effectively hyperparasitized and lysed the mycelium of F. oxysporum f. sp. cucumerinum F1, egg mass and individual eggs of root-knot nematode. Further, GC–MS profiling of the agar plugs, excised from the point of hyperparasitism by TRI 41, from the dual plate assay revealed a shift in the non-volatile organic compounds (NVOC) profile. In vitro, TRI 41 produced maximum indole acetic acid (IAA) (15.25 µg/ml) and gibberellic acid (GA) (10.40 µg/ml) in PDB. T. koningiopsis TRI 41 increased the root length (28.74 cm), shoot length (14.64 cm) and stem girth (1.76 cm) of cucumber seedlings to the maximum in vermicompost:soil:sand medium. Furthermore, TRI 41 influenced the root architecture of cucumber plants and altered the root exudate pattern in the rhizosphere of 35-day-old cucumber seedlings. Various non-volatile organic compounds with antifungal and antibacterial activity were detected in the rhizosphere. Under field conditions, seed treatment with the consortia of the isolates, including T. koningiopsis TRI 41, Trichoderma asperellum TRI 15 and Trichoderma asperelloides TNAU Tad 1 @ 1 ml/kg of seed (0.1%) applied as soil drenching (100 ml of gel formulation in 100 L of water over 1000 m2 area of polyhouse), indicated that the incidence of fungal nematode complex was reduced to 13.45% with 80.0 fruits/plant with a mean yield of 15.01 t/1000m2. For instance, the untreated control was reported with 41.32 percent disease incidence, 52.0 fruits/plant with a mean yield of 10.20 t/1000m2.