The Endoparasitic Nematophagous Fungus Meria coniospora Infects Nematodes Specifically at the Chemosensory Organs

Abstract

Conidia of the endoparasitic fungus Meria coniospora infected the bacterial-feeding nematode Panagreflus rediviuus at specific sites, namely the mouth region and in male nematodes also in the tail. Plant-parasitic nematodes were also infected in other parts of the body. The specific infection sites in P. redivivus were the sensory organs, which are the sites of chemoreception.Blocking of chemoreceptors by adhered conidia of M . coniospora caused a complete loss of the ability of nematodes to be attracted to different sources of attractants. Inhibition of conidial adhesion by means of sugar haptens suggested a lectin-carbohydrate interaction. Out of 21 sugars only N-acetylneuraminic acid inhibited the adhesion, indicating the importance of sialic acids in the infection process. Reduction of conidial adhesion by treatment of nematodes with neuraminidase further supported this view.

Conidia of the nematophagous fungus Drechmeria coniospora adhere to but barely infect Acrobeloides buetschilii

“…Previous studies with Acrobeloides spp. showed that adhesion, if observed, almost invariably occurred in the mouth region, but seldom in other parts of the nematode [1]. In our study adhesion to the nematode body also occurred, although less abundantly than to the mouth region.…”

“…With P. redivivus, germination of conidia of D. coniospora and penetration of the cuticle occurs within 1 h after adhesion [3]. A delay in penetration following adhesion has been observed after treatment of different species of mainly plant and animal parasitic nematodes with conidia of D. coniospora [1,5,6]. This indicates that adhesion itself is not sufficient to facilitate infection.…”

“…The endoparasitic fungus Drechmeria coniospora infects nematodes by means of conidia which possess an adhesive knob at the apical site. In the case of the free-living nematode Panagrellus redivivus adhesion occurred near the sensory organs located on the head and/or tail end [1]. After adhesion, an appressorium is formed on the knob which is shown to be a prerequisite for proper penetration of the prey [2,3].…”

A Model for Evolutionary Ecology of Disease: The Case for Caenorhabditis Nematodes and Their Natural Parasites

“…Duveau, 2012). It can infect a broad range of nematode species (Jansson and Nordbring-Hertz, 1983), suggesting that it likely infects C. elegans naturally. Jansson et al (1985), Jansson (1994), F elix and Duveau 2012Bacteria Leucobacter musarum japonicus a…”

Caenorhabditis elegans

“…coniospora spores can adhere to the head of a nematode, then extend hyphae into the body, via the open ends of sensory neurons [13,14]. For the first day or two, the worms appear healthy, but then die and rapidly become engulfed by the hyphae that sprout from the inside (Fig.…”