High infectivity of an endoparasitic fungus strain, Esteya vermicola, against nematodes

Abstract

Esteya vermicola, as the first recorded endoparasitic fungus of pinewood nematodes, exhibits great potential as a biological agent against nematodes. However, only two strains of this species have been described so far. In this study, we identified a novel endoparasitic fungal strain, CNU 120806, isolated from infected nematodes in forest soil samples during a survey of nematophagous fungi in Korea. This strain showed similar morphological characteristics and infection mode with the two previously described strains of E. vermicola. All strains are characterized by the ability to produce two types of conidiogenous cells and conidia, and to parasitize nematodes with lunate adhesive conidia. Moreover, the CNU 120806 strain showed 100% identity with E. vermicola CBS 115803 when their partial sequences of 28S rRNA gene were compared. Molecular phylogenetic analysis further identified CNU 120806 as a strain of E. vermicola, by clustering CNU 120806 and E. vermicola CBS 115803 into a single subclade. Culture medium influenced the proportion of dimorphic CNU 120806 conidia, and further changed the adhesive and mortality rates of nematodes. The CNU 120806 strain exhibits high infection activity against nematodes on nutrient-rich PDA medium. Almost all tested nematodes were killed within 8 approximately 10 days after inoculation. This study provides justification for further research of E. vermicola, and the application and formulation of this fungus as a bio-control agent against nematodes.

Efficacy of commercial wood preservatives against Bursaphelenchus xylophilus, a quarantine organism in Europe

“…IPBC is a known fungicide/antimicrobial (Edlund andNilsson 1999, Uzunovic et al 2013) therefore, if fungal growth is inhibited, the development of the nematode populations is prevented due to lack of food (due to the fungivorous life traits of B. xylophilus). This preference of B. xylophilus for blue stain fungi confirms the results of Fukushige (1991) and Wang et al (2008). The corresponding PCA for stained and non-stained dry wood are presented in Fig.…”

A parasitological paradox: Why is ascarid infection so rare in the prehistoric Americas?

“…Currently, 150 species are known, divided in three groups: nematode predators, endoparasites, and egg opportunistic parasites (Gray, 1987). Many genera, such as Arthrobotrys, Duddingtonia, Pochonia and Monascroporium are efficient in controlling animal intestinal parasitosis (Wang et al, 2008;Araújo et al, 2009aAraújo et al, , 2009bBraga et al, 2009aBraga et al, , 2009bCarvalho et al, 2009;Kelly et al, 2009;Maciel et al, 2009aMaciel et al, , 2009b. These fungal taxa are distributed throughout the world and in every kind of climate (Gray, 1987).…”

Esteya vermicola Controls the Pinewood Nematode, Bursaphelenchus xylophilus, in Pine Seedlings

“…Spraying E. vermicola on the wounds ensures a higher survival rate than that of ''no wound seedlings.'' After E. vermicola enters a pine tree through a wound, the PWNs are attracted by volatile organic compounds produced by E. vermicola, and the fungus eventually kills the nematodes (Wang et al, 2008). Similarly, the conidia of B. cinerea sprayed onto the wounds of pine seedlings caused more damage compared to ''no wound seedlings.''…”