Submitted to: International Congress of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: June 8, 2002
Publication Date: N/A
Technical Abstract: Novel molecular traits are needed for nematode phylogeny and diagnostics, particularly when source specimens are limited or when currently used molecules do not provide enough molecular discrimination to distinguish genera, species, or isolates. We have examined the hsp90 gene as a single-copy diagnostic molecule for nematodes at several taxonomic levels. We used degenerate primer PCR to amplify partial hsp90 genomic sequences from a broad range of bacterial-feeding and plant-parasitic nematode genera. Genomic DNA alignments showed that hsp90 introns had species-specific arrangements and genus-specific sizes. HSP90 amino acid phylogeny revealed several nematode-specific residues, and placed nematodes paraphyletic to insects. These results demonstrate that hsp90 is informative and useful for evaluating the evolutionary relationships within and between nematodes and other organisms. We performed another study to detect the presence of hsp90 polymorphisms that may be useful for discrimination of nematodes at the sub-species level. Comparison of hsp90 genomic sequences from several highly inbred strains of the soybean cyst nematode, Heterodera glycines, revealed unique combinations of intron polymorphisms in some strains, thus demonstrating the potential of this gene for discrimination of soybean cyst nematode genotypes.