AUTHOR=Pocurull Miriam , Fullana Aïda M. , Ferro Miquel , Valero Pau , Escudero Nuria , Saus Ester , Gabaldón Toni , Sorribas F. Javier 

TITLE=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

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.03042

DOI=10.3389/fmicb.2019.03042

ISSN=1664-302X

ABSTRACT=<p><italic>Meloidogyne</italic> is the most damaging plant parasitic nematode genus affecting vegetable crops worldwide. The induction of plant defense mechanisms against <italic>Meloidogyne</italic> in tomato by some <italic>Trichoderma</italic> spp. strains has been proven in pot experiments, but there is no information for tomato bearing the <italic>Mi-1.2</italic> resistance gene or for other important fruiting vegetable crops. Moreover, <italic>Trichoderma</italic> 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 <italic>Trichoderma asperellum</italic> (T34) and <italic>Trichoderma harzianum</italic> (T22) to induce systemic resistance in tomato and cucumber against an avirulent <italic>Meloidogyne incognita</italic> population in split-root experiments; (ii) the effect of combining T34 with tomato carrying the <italic>Mi-1.2</italic> resistance gene to an avirulent <italic>M. incognita</italic> population in sterilized soil; and (iii) the effect of combining T34 with tomato carrying the <italic>Mi-1.2</italic> resistance gene to a virulent <italic>M. incognita</italic> population in two suppressive soils in which <italic>Pochonia chlamydosporia</italic> is naturally present, and the effect of T34 on the level of <italic>P. chlamydosporia</italic> egg parasitism. Both <italic>Trichoderma</italic> formulates induced resistance to <italic>M. incognita</italic> 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 <italic>M. incognita</italic> population in both resistant and susceptible tomato cultivars irrespective of the suppressive soil, and its effect was additive with the <italic>Mi-1.2</italic> resistance gene. The percentage of fungal egg parasitism by <italic>P. chlamydosporia</italic> was not affected by the isolate T34 of <italic>T. asperellum</italic>.</p>