Parasitism of Trichoderma on Meloidogyne javanica and role of the gelatinous matrix

Abstract

Trichoderma (T. asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived eggs and second-stage juveniles (J2) were parasitized by Trichoderma asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi. The gelatinous matrix specifically induced J2 immobilization by T. asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca 2+ -dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes. All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinousmatrix-coated nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching and appressorialike structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of

Evaluation of Some Botanicals and Trichoderma harzianum for the Management of Tomato Root-knot Nematode (Meloidogyne incognita (Kofoid and White) Chit Wood)

“…These compounds act by various mechanisms like blocking molting of larvae, disrupting mating and sexual communication of nematodes, reducing the motility of gut and by inhibiting the formation of chitin [62]. Sharon et al [63] showed that eggs adhered with Trichoderma conidia became non-viable, thus decreasing the eclosion rate. In this study, the botanicals used only they were effective but when they were used in combination they show less effective so it is evident that as extract was diluted, toxicity was decreased resulting in correspondent decrease in inhibition and any inhibition was observed in distilled water.…”

Evaluation of some botanicals and Trichoderma harzianum against root-knot nematode (Meloidogyne incognita (Kofoid and White) Chit wood) in tomato

“…It was found that the gelatinous matrix enables fungal attachment and enhances parasitic abilities of most isolates, which could also utilize it as a nutrient source (Sharon et al, 2009). The conidia of Trichoderma attach to nematode cuticle or to egg shell and parasitize on them (Sharon et al, 2007). Al Kader (2008) reported a high nematicidal effect of the fungus Paecilomyces lilacinus culture filtrate on J 2 of M. incognita, with 99% of J2 immobilized after 2 days of treatment.…”

Reclassification of Trichoderma Viride (TNAU), the Most Widely Used Commercial Biofungicide in India, as Trichoderma Asperelloides

“…In their studies, Samuels et al [9] reclassified many widely used "T. viride" strains as T. asperelloides. Some of the extensively used strains that have been reclassi *Address correspondence to this author at the Crop Protection Division, Central Institute for Cotton Research, Nagpur 440010, India; Tel: +91-7103-275538; Fax: +91-7103-275529; E-mail: prasunmukherjee1@gmail.com fied are T. harzianum T103 [10], T. asperellum T44 [11], T. viride ATCC 52439 and TR 31 [12]. T. viride strain, isolated and developed at the Tamil Nadu Agricultural University, Coimbatore, India [13] is the most popular biofungicides approved by the Central Insecticides Board (CIB), Govt.…”