Arthrobotrys oligospora (Fungi: Orbiliales) and its liquid culture filtrate myco-constituents kill Haemonchus contortus infective larvae (Nematoda: trichostrongylidae)

ABSTRACT

Arthrobotrys oligospora is a nematode-trapping fungus belonging to the family Orbiliaceae and one of the main antagonists of nematodes in soil, including plant and animal parasitic nematodes and free-living nematodes. This species develops three-dimensional adhesive nets in which nematodes are trapped, destroyed and consumed by the fungus. It also possesses other strategies to immobilise, kill and degrade nematodes, i.e. nematode-attractant substances, cuticle adhesion polymers and a number of nematocidal metabolites. The objective of this study was to assess the in vitro nematocidal activity of a strain of A. oligospora through its predatory activity and its liquid culture filtrates (LCF) against the ruminant parasite Haemonchus contortus (HcL3) and to investigate the presence of myco-compounds with potential nematocidal activity. Predatory activity (PA) was assessed in agar plates; 200 HcL3 were placed on agar plates with the fungus and a control group and incubated for 10 days. The LCF confrontation with nematodes was performed in microtiter plates. Two media, Czapek-Dox Broth (Cz-DB) and potato dextrose broth, were assessed. Three concentrations (25, 50 and 100 mg/mL) were assessed at 48 and 72 h (n = 4, per concentration). The experiment was performed in triplicate. The results showed 73.6 ± 2.7% PA and the highest mortality (83%) with the LCF in Cz-DB after 72 h. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that the A. oligospora ethyl acetate phase was composed of 1,2-benzenedicarboxylic acid, bis (2-methylpropyl) ester, (M) 1,4-benzenedicarboxylic acid, bis (2-methylpropyl) ester and (M) decanedioic acid (2-ethylexyl) ester. These compounds could be responsible for nematocidal activity.

KEYWORDS:

• Nematodes
• nematophagous fungi
• predation
• nematocidal
• myco-compounds

Acknowledgments

This study formed part of the Thesis Project of Miss Daira Samantha Bahena-Nuñez to obtain her bachelor′s degree as an Engineer in Biotechnology by Universidad Politécnica del Estado de Morelos (UPEMOR), Mexico, under the direction of Dr. Pedro Mendoza de Gives and Dr. Ana Yuridia Ocampo-Gutiérrez. This study received financial support by Consejo Nacional de Humanidades, Ciencias y Tecnología (CONACYT), Proyecto Ciencia de Frontera CF-2023-I-2309.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

Daira Samantha Bahena-Núñez: writing the first protocol, laboratory work, methodology, analysis of results and writing; Ana Yuridia Ocampo-Gutiérrez: laboratory work, analysis and discussion of results; Pedro Mendoza de Gives: conceptualisation, investigation and writing of the manuscript; Manasés González-Cortázar: analysis of chemical compounds; Alejandro Zamilpa: GC–MS analysis; Rosa Isabel Higuera-Piedrahita: review and editing; Gustavo Pérez-Anzúrez: fungal laboratory activities; Agustín Olmedo-Juárez: statistical analysis; María Eugenia López-Arellano: discussion of results and revision of the manuscript; Edgar Jesús Delgado-Núñez: commenting and discussing results of the analysis of chemical compound and Jesús Hernández-Romano: molecular analysis. All authors read and approved the final manuscript.

Data availability

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request, while sequences are publicly available in NCBI Genbank.

Additional information

Funding

Dr Ana Yuridia Ocampo-Gutiérrez received economic support from CONACYT as a Post-doctoral stay: (Estancias post-doctorales por México, 2022), CVU number: 558884 under the direction of Dr. Rosa Isabel Higuera-Piedrahita from FES-Cuautitlán, UNAM, México. Consejo Nacional de Ciencia y Tecnología.