Use of Trichoderma Hamatum for Biocontrol of Lentil Vascular Wilt Disease: Efficacy, Mechanisms of Interaction And Future Prospects

Abstract

Trichoderma hamatum (Bonord.) Bainier was evaluated for its antagonistic potential against Fusarium oxysporum Schlecht. emend. Snyder and Hansen sp. lentis, the causal agent of vascular wilt disease of lentil (Lens culinaris Medikus). Hyphal interactions on Petri plates resulted in an increase in the number of conidial spores and an increase in the vegetative growth of T. hamatum, and a decrease in the hyphal formation and sporulation of F. oxysporum f. sp. lentis. Electron and light microscopical observations suggested that hyphae of T. hamatum established aggressive contact and attachment with the hyphae of the pathogen. Growing in parallel, coiled densely and tightly, T. hamatum may penetrate those of the pathogen hyphae causing collapse due to the loss of turgor pressure. The cellulolytic enzymes produced by T. hamatum presented sufficient characteristics for its antifungal activity in the hyphae hydrolysis and competition process. In growth room and glasshouse experiments, the addition of the conidial suspension of T. hamatum or its culture filtrate to soil, significantly (p ≤ 0.05) reduced development and spore germination of F. oxysporum. In the rhizosphere, T. hamatum occupied the same ecological niches (rhizosphere, roots, and stems) parasitizing F. oxysporum f. sp. lentis. Treatments using T. hamatum delayed the time of infection by F. oxysporum, promoted the growth, and increased the dry weight of a susceptible variety of lentil (cv. Precoz). The percent of mortality was reduced to 33 and 40% when using T. hamatum and its filtrate, respectively, compared to 93% in the control treatment during the 65 days of growing in loam/sand (2:1 vol/vol) under glasshouse conditions. Plant colonization results indicate that T. hamatum and its filtrate significantly (p ≤ 0.05) reduced development of the pathogen in the vascular tissue of lentil to < 30 and < 40% stem colonization, respectively, compared to 100% in the plant pathogen control. Our results suggest that potential biocontrol mechanisms of T. hamatum towards F. oxysporum f. sp. lentis were antibiosis by production of antifungal enzymes, complex mechanisms of mycoparasitism, competition for key nutrients and/or ecological niches, growth promotion, and a combination of these effects. This study results hold important suggestions for further development of effective strategies of the biological control of Fusarium vascular wilt of lentil.

Diversity, plant growth‐promoting traits, and biocontrol potential of fungal endophytes of Sorghum bicolor

“…The antagonistic mechanisms of Trichoderma against phytopathogens are in agreement with the mechanism reported by earlier researchers. El‐Hassan et al () also reported that biocontrol of Fusarium oxysporum f. sp. lentis using Trichoderma hamatum was associated with production of antifungal enzymes, complex mechanisms of mycoparasitism, and decreased hyphal formation and sporulation of the pathogen.…”

“…Endophytic fungi are well known for their plant growth‐promoting traits and inducing protection against biotic and abiotic stress. They deter potential pathogens by inducing chemical responses of their hosts or by directly inhibiting colonization via interference competition (El‐Hassan et al , ).…”

“…This trait is attributed to the ability of the endophytes to produce IAA and siderophore, phosphate solubilization, and cellulase activity. About 59% of the isolated endophytes exhibited IAA production that benefits the plant by allowing higher nutrient intake, early seedling establishment, and induces lateral root formation resulting in increased root length (El‐Hassan et al , ; Kumar et al , ). The second highest plant growth‐promoting trait observed in the isolated endophytes was phosphate solubilization.…”

Systemic protection against pearl millet downy mildew disease induced by cell wall glucan elicitors from Trichoderma hamatum UOM 13

“…Spatial separation of T. hamatum and P. cap sici established the systemic nature of resistance induction in cucumber (Khan et al 2004). Trichoderma hamatum efficiently controlled vascular wilt disease of lentils caused by Fusarium oxysporum (El-Hassan et al 2013).…”

Biocontrol of Sclerotium rolfsii in Groundnut by Using Microbial Inoculants

“…In particular, the rhizospheric symbiont AM fungi not only increases the nutrient uptake efficiency of most agricultural crops but are also known to increase soil structure and suppress diseases (Ziedan et al, 2011;Verbruggen et al, 2013). The saprophytic symbiont Trichoderma species are also associated with the plant roots which help in growth promotion and inhibition of important plant diseases (Hohmann et al, 2011;El-Hassan et al, 2013). As AM fungi is interacting with most rhizospheric organisms, the interaction studies between AM fungi and Trichoderma species has received positive attentions whose species number is still increasing (Doley and Jite, 2012a;Tanwar et al, 2013;Yabuki et al, 2014).…”