Ecophysiological characteristics of the nematophagous fungus, Plectosphaerella plurivora, with biocontrol potential on Nacobbus aberrans s.l. in tomato.

Abstract

The plant-parasitic nematode, Nacobbus sp., is responsible for significant economic losses in horticultural production centers in Argentina and other countries in America, alone or in combination with other biotic and abiotic factors. Although the genus distribution is restricted to the American continent, it has quarantine importance and is subject to international legislation to prevent its spread to other regions. The management of phytoparasitic nematodes through biological control strategies is a promising eco-compatible alternative, allowing the sustainability of the crop horticultural system. Results of this study, firstly allowed ecophysiologically characterize Plectosphaerella plurivora SRA14, a strain with nematophagous activity on N. aberrans s.l. This fungal strain developed in vitro under a wide temperature range (20-30 °C), nevertheless the highest levels of water stress (Ψ: -7 and -10 Mpa; aW: 0.95 and 0.93) inhibited its growth. Notwithstanding, the production of extracellular enzymes by this strain was low, P. plurivora SRA14 was able to develop in the rhizosphere and endorhizosphere of the tomato and basil crops without affecting the plant vigor parameters and producing phytotoxicity signs. Secondly, this study evidenced the biocontrol activity of P. plurivora SRA14 on N. aberrans s.l. population in tomato implanted both on sterile (artificially inoculated) and naturally infested soils via greenhouse pot experiments. The results of this work revealed for the first time the potential of P. plurivora SRA14 to consolidate itself as a biological control agent of the phytoparasitic nematode, N. aberrans s.l., in horticultural crops.