Hirsutella thompsonii and Pochonia chlamydosporia (Syn. Verticillium chlamydosporium) Mycelia Growth and Predation on Panagrellus redivivus

Cleonice Lubian,Maria Eunice Lima Rocha,Roberto Luis Portz,Tatiane Priscila Chiapetti,Luanna Karoline Rinaldi,Camila Hendges,Danielle Dutra Matinha,Mayra Taniely Ribeiro Abade,Vivian Carré Missio

doi:10.5539/jas.v9n11p137

Abstract

This research aimed to evaluate the nematophagous ability of 4077-Verticillium chlamydosporium var. chlamydosporium and 4466-Hirsutella thompsonii isolates and relate mycelia growth to the influence provoked by movement of nematodes. Each fungus grew in PDA (potato, dextrose, agar) medium end up to pure colonization. Then, ten mycelia plugs of 8 mm diameter were removed from colony borders and transferred to the center of ten Petri plates containing water-agar 2% medium. These plates were previously divided into four quadrants that received a number of 25 individuals of free-living nematodes (Panagrellus redivivus), composing a total of 100 nematodes per plate. Evaluations started after 24 hours of interaction, considering predation percentage and mycelia growth as stimuli of nematodes presence. Results showed growing predation performance to both isolates, being higher for V. chlamydosporium var. chlamydosporium since from first evaluation time, controlling more than 50% of nematode population initially added. Its predation potential was 39.2%, 38.4% and 48.35% higher than H. thompsonii at first, second and third evaluation day, respectively. Generally, nematodes did not stimulate mycelia growth, unless for H. thompsonii at 72 hours of interaction compared to control plates (without nematodes). Stress resulting from isolates transference from PDA to water-agar 2% resulted in sparse mycelia growth and it could have affected the predation performance of H. thompsonii that controlled nematodes in low levels throughout experiment. Independently of predation level, pictures revealed that both isolates has ability to control P. redivivus through hyphae penetration.

Highlights

Biological control of parasitic nematodes represents a viable strategy to minimize chemical application that causes lots of damage in soil biotic microorganisms (Morandi et al, 2009)
Some species belonging to Hirsutella showed ability as biological agents under greenhouse trials (Xiang et al, 2007), as well as Pochonia chlamydosporia
The present study aimed to determine predation of the free-living nematode Panagrellus redivivus by 4077-Verticillium chlamydosporium var. chlamydosporium and 4466-Hirsutella thompsonii isolates and relate mycelia growth to the influence provoked by movement of nematodes

Summary

Introduction

Biological control of parasitic nematodes represents a viable strategy to minimize chemical application that causes lots of damage in soil biotic microorganisms (Morandi et al, 2009). Fungi are preferred due to their ability on capture and digest nematodes, even free-living ones. In this process, hyphae modifications may occur in some species in order to hold nematodes before preying, changing growth pattern (Chen & Dickson, 2004). Verticillium chlamydosporium) that releases nematicidal substances (Khambay et al, 2000). Both genera are saprophytic and P. chlamydosporia plays an important role as plant growth promoter (Macia-Vicente et al, 2009)

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