Plant Health and Rhizosphere Microbiome: Effects of the Bionematicide Aphanocladium album in Tomato Plants Infested by Meloidogyne javanica

Abstract

The artificial introduction in the soil of antagonistic microorganisms can be a successful strategy, alternative to agrochemicals, for the control of the root-knot nematodes (<i>Meloidogyne</i> spp.) and for preserving plant health. On the other hand, plant roots and the associated rhizosphere constitute a complex system in which the contribution of microbial community is fundamental to plant health and development, since microbes may convert organic and inorganic substances into available plant nutrients. In the present study, the potential nematicidal activity of the biopesticide <i>Aphanocladium album</i> (<i>A. album</i> strain MX-95) against the root-knot nematode <i>Meloidogyne javanica</i> in infected tomato plants was investigated. Specifically, the effect of the <i>A. album</i> treatment on plant fitness was evaluated observing the plant morphological traits and also considering the nematode propagation parameters, the <i>A. album</i> MX-95 vitality and population density. In addition, the treatment effects on the rhizosphere microbiome were analysed by a metabarcoding procedure. Treatments with <i>A. album</i> isolate MX-95 significantly decreased root gall severity index and soil nematode population. The treatment also resulted in increased rhizosphere microbial populations. <i>A. album MX-95</i> can be favourably considered as a new bionematicide to control <i>M. javanica</i> infestation.