Scanning electron microscopic and energy dispersive X-ray spectroscopic studies of Drechmeria coniospora, an endoparasitic nematophagous fungus

Geeta Saxena

Sydowia 74: 133-142

Published online on August 30th, 2021

Nematophagous fungi are promising biological agents for the control of plant parasitic nematodes. Three general groups of nematophagous fungi are categorized based on the mechanism by which they attack nematodes: Nematode-trapping or predatory fungi, Egg parasitic fungi of cyst and root-knot nematodes and Endoparasitic fungi. In this study, scanning electron microscopy and energy dispersive X- ray spectroscopy has been done on an obligate endoparasite Drechmeria coniospora. Its conidia produce adhesive buds to attach, infect and parasitize nematodes. D. coniospora was isolated from compost soil, grown in pure culture with Panagrellus redivivus nematode suspensions on dialysis membrane and freeze dried for these studies. Eight elements namely Na+, Mg2+, Si, P, S, Cl-, K+ and Ca2+ were analyzed. Freeze drying was useful in preserving the original structure of the fungus. Several conidiophores breaking out from the whole nematode body were observed. They formed conidiiferous pegs which in turn produced cluster of conical conidia. Elemental analysis of young and mature conidiophores, conidiiferous pegs and young and mature conidia showed high P, S and K+ contents. Although scanning electron microscopic studies have been done previously on D. coniospora, energy dispersive X- ray spectroscopy is the first attempt to study any endoparasitic fungus.

Keywords: nematophagous fungi, endoparasite, biocontrol, elemental analysis, conidiophores.

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