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Orchid mycorrhizal fungus from the Brazilian Cerrado exhibits biocontrol activity against Meloidogyne javanica.

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Title: Orchid mycorrhizal fungus from the Brazilian Cerrado exhibits biocontrol activity against Meloidogyne javanica.
Authors: Mendes, Bruno Leonardo1 (AUTHOR) bleomendes@gmail.com, Faria, Denner Robert1 (AUTHOR), Sousa, Kellen Cristhina Inácio2 (AUTHOR), Costa, Matheus Pereira Lima1 (AUTHOR), da Rocha, Mara Rúbia1 (AUTHOR), de Araújo, Leila Garcês3 (AUTHOR)
Source: Mycorrhiza. Dec2025, Vol. 35 Issue 6, p1-12. 12p.
Subject Terms: *Javanese root-knot nematode, *Mycorrhizal fungi, *Cerrados, *Sustainability, *Plant growth, *Root-knot nematodes, *Biological pest control agents, *Biological pest control
Abstract: Waitea circinata, an orchid-associated mycorrhizal fungus, was evaluated for the first time as a biological control agent against the root-knot nematode Meloidogyne javanica. The fungus was originally isolated from the roots of Epidendrum nocturnum, a rupicolous orchid to the Brazilian Cerrado. In vitro assays demonstrated that W. circinata parasitized nematode eggs, with parasitism rates of 13–15% and characteristic emergence of septate hyphae with right-angle branching. Microscopy revealed eggshell degradation, arrested embryogenesis, and juvenile deformation. A mycelial suspension (MSF) of the fungus increased juvenile (J2) mortality in a dose-dependent manner, suggesting the action of nematicidal metabolites. In greenhouse experiments, W. circinata significantly reduced the nematode reproduction factor (RF), with values dropping from above 5 in the control to below 1 at the highest concentrations. In addition, MSF application promoted plant growth, increasing root length, root mass, and shoot height. No phytotoxic effects were observed at any dose. Principal component analysis confirmed a negative correlation between nematode-related variables and plant development, reinforcing the dual action of W. circinata in nematode suppression and plant stimulation. These effects are likely mediated by a combination of mechanisms, including parasitism, enzyme activity, antibiosis, and the production of phytohormones. The results highlight W. circinata as a promising candidate for the sustainable management of plant-parasitic nematodes and the enhancement of crop performance. [ABSTRACT FROM AUTHOR]
Database: Energy & Power Source
Description
Abstract:Waitea circinata, an orchid-associated mycorrhizal fungus, was evaluated for the first time as a biological control agent against the root-knot nematode Meloidogyne javanica. The fungus was originally isolated from the roots of Epidendrum nocturnum, a rupicolous orchid to the Brazilian Cerrado. In vitro assays demonstrated that W. circinata parasitized nematode eggs, with parasitism rates of 13–15% and characteristic emergence of septate hyphae with right-angle branching. Microscopy revealed eggshell degradation, arrested embryogenesis, and juvenile deformation. A mycelial suspension (MSF) of the fungus increased juvenile (J2) mortality in a dose-dependent manner, suggesting the action of nematicidal metabolites. In greenhouse experiments, W. circinata significantly reduced the nematode reproduction factor (RF), with values dropping from above 5 in the control to below 1 at the highest concentrations. In addition, MSF application promoted plant growth, increasing root length, root mass, and shoot height. No phytotoxic effects were observed at any dose. Principal component analysis confirmed a negative correlation between nematode-related variables and plant development, reinforcing the dual action of W. circinata in nematode suppression and plant stimulation. These effects are likely mediated by a combination of mechanisms, including parasitism, enzyme activity, antibiosis, and the production of phytohormones. The results highlight W. circinata as a promising candidate for the sustainable management of plant-parasitic nematodes and the enhancement of crop performance. [ABSTRACT FROM AUTHOR]
ISSN:09406360
DOI:10.1007/s00572-025-01233-4