Evaluation of root-gall associated fungal endophytes for the control of Meloidogyne graminicola infecting rice

Article Type

Research Article

Publication Title

Biological Control

Abstract

In the rice-producing regions of India, the infection of the rice root-knot nematode Meloidogyne graminicola represents a significant biotic constraint that leads to substantial yield reduction. Traditional nematode management practices are neither cost-effective nor environmentally friendly. Consequently, there is an urgent need to identify potential biocontrol agents for effectively managing this destructive pest. M. graminicola infestation in rice incites the formation of terminal root galls, which serve as multinucleated food sinks inhabited by nematodes and other endophytic microorganisms. In our study, we isolated and screened fungal endophytes associated with healthy and galled rice roots to identify potential biocontrol agents against the nematode. Among the isolated fungi, a gall-associated endophytic fungus identified as Aspergillus niger isolate F4 exhibited 100% juvenile (J2) mortality under in vitro conditions at 50% culture filtrate concentration, within 24 h of inoculation, with an LC50 of 10.85%. Additionally, it demonstrated ovicidal properties by inhibiting egg hatching by 96.96% compared to the control. Furthermore, the attraction assay revealed a significantly lower number of M. graminicola J2s attracted to rice roots treated with F4 culture filtrate compared to untreated roots. In an in vivo pot experiment, root dipping with F4 culture filtrate reduced the galling index, the number of J2s penetrating the root, and the reproduction factor. Besides the direct effects, inoculation of the fungus also triggered plant defence responses, potentially providing indirect protection against nematode infection. Overall, our study, to the best of our knowledge, is the first to demonstrate that M. graminicola root galls harbour specific endophytic fungi with potent biocontrol properties. The available evidence clearly establishes the potential of Aspergillus niger F4 as an important biological control agent against M. graminicola, offering a novel management approach for this significant rice pest.

DOI

https://10.1016/j.biocontrol.2023.105341

Publication Date

11-1-2023

This document is currently not available here.

Share

COinS