Commercial Formulates of Trichoderma Induce Systemic Plant Resistance to Meloidogyne incognita in Tomato and the Effect Is Additive to That of the Mi-1.2 Resistance Gene

Abstract

Meloidogyne is the most damaging plant parasitic nematode genus affecting vegetable crops worldwide. The induction of plant defense mechanisms against Meloidogyne in tomato by some Trichoderma spp. strains has been proven in pot experiments, but there is no information for tomato bearing the Mi-1.2 resistance gene or for other important fruiting vegetable crops. Moreover, Trichoderma is mostly applied for managing fungal plant pathogens, but there is little information on its effect on nematode-antagonistic fungi naturally occurring in soils. Thus, several experiments were conducted to determine (i) the ability of two commercial formulates of Trichoderma asperellum (T34) and Trichoderma harzianum (T22) to induce systemic resistance in tomato and cucumber against an avirulent Meloidogyne incognita population in splitroot experiments; (ii) the effect of combining T34 with tomato carrying the Mi-1.2 resistance gene to an avirulent M. incognita population in sterilized soil; and (iii) the effect of combining T34 with tomato carrying the Mi-1.2 resistance gene to a virulent M. incognita population in two suppressive soils in which Pochonia chlamydosporia is naturally present, and the effect of T34 on the level of P. chlamydosporia egg parasitism. Both Trichoderma formulates induced resistance to M. incognita in tomato but not in cucumber. In tomato, the number of egg masses and eggs per plant were reduced by 71 and 54% by T34, respectively. T22 reduced 48% of the number of eggs per plant but not the number of egg masses. T34 reduced the number of eggs per plant of the virulent M. incognita population in both resistant and susceptible tomato cultivars irrespective of the suppressive soil, and its effect was additive with the Mi-1.2 resistance gene. The percentage of fungal egg parasitism by P. chlamydosporia was not affected by the isolate T34 of T. asperellum. Frontiers in Microbiology | www.frontiersin.org 1 January 2020 | Volume 10 | Article 3042 Pocurull et al. Additive Effect Trichoderma-Mi1.2 Against RKN Conflict of Interest:The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Biological Control of Plant-Parasitic Nematodes by Filamentous Fungi Inducers of Resistance: Trichoderma, Mycorrhizal and Endophytic Fungi

“…Furthermore, it has been recently described that commercial formulates of some Trichoderma spp. strains induced resistance to M. incognita in tomato in split-root system experiments and additionally, an additive effect to that of the tomato Mi 1.2 resistance gene was also observed (Pocurull et al, 2020). It opens possibilities for integrated pest management of root-knot nematodes with BCAs and other combined control methods.…”

Bacillus firmus Strain I-1582, a Nematode Antagonist by Itself and Through the Plant

“…This temperature is suboptimal for Meloidogyne , which could further enhance its antagonistic activity. Additional studies are required for maximizing its antagonistic potential and to design successful RKN management strategies, such as the bacterial capability to induce resistance in other important vegetable crops frequently included in rotation sequences; the putative effect of the induced resistance against virulent nematode populations to selected R- genes, as observed with the additive effects of resistance induced by Trichoderma asperellum isolate T34 in tomato with the Mi1.2 gene against a virulent M. incognita population ( Pocurull et al, 2020 ) and the optimal timing for B. firmus I-1582-based formulations application under field conditions, among others.…”

Deciphering Trichoderma–Plant–Pathogen Interactions for Better Development of Biocontrol Applications

“…In particular, two of the most extensively studied mechanisms for plant induced defenses are pathogen-induced systemic acquired resistance (SAR) and induced systemic resistance (ISR) triggered by mutualistic microbes such as Trichoderma spp. [ 60 , 67 ]. A significant body of recent literature has documented the potentiation and stimulation of plant defense responses by Trichoderma spp.…”