Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: August 7, 2004
Publication Date: September 1, 2004
Citation: Meyer, S.L., Carta, L.K., Rehner, S.A. 2004. Morphological and molecular comparisons between monacrosporium drechsleri and related nematode-trapping fungi. Journal of Nematology 36(3): 334.
Population densities of the nematode Meloidogyne arenaria, grown on tomato roots in the ARS Beltsville Nematology Laboratory greenhouse, declined after years of successful maintenance. Individual M. arenaria specimens from the pots were examined for fungal parasitism. The nematophagous fungus Monacrosporium drechsleri was subsequently isolated from second-stage juveniles of M. arenaria. Although no individuals of the free-living Diploscapter spp. observed from the same pots were visibly parasitized, adhesive knobs formed by cultures of the M. drechsleri isolate trapped all genera of nematodes tested in Petri dish cultures, including the plant parasites Heterodera glycines, Meloidogyne incognita, Pratylenchus zeae, and the free-living nematodes Caenorhabditis elegans and Panagrellus redivivus. To examine relationships of M. drechsleri with other Monacrosporium species, the Beltsville isolate was compared with the morphologically similar species M. ellipsosporum and M. lysipagum, and with the less similar species M. parvicolle. The ITS-1 and -2 regions of rDNA and the nuclear gene EF1-alpha were sequenced for all four species. Parsimony trees indicated that the closest molecular relative of M. drechsleri was M. ellipsosporum; however, the tested M. ellipsosporum isolate (ATCC 204100) had a highly divergent sequence from that previously recorded in GenBank for a different isolate morphologically identified as M. ellipsosporum (CBS 224.54, GenBank accession U51971). The morphological characters can be difficult to use in separation of some of these taxa, demonstrating the usefulness of molecular characters for identification.