Isolation and molecular characterization of the heat shock protein-90 gene (hsp-90) in three Steinernema species from Georgia

A portion of the hsp-90 gene was amplified, using degenerate primers, in Steinernema thesami, S. tbilisiensis and Steinernema sp. isolated in Georgia. Two amplified products were obtained for each species and both fragments were cloned and sequenced. Blast search at NCBI revealed that both fragments for each species coded for hsp-90. Sequence analyses revealed that all three Steinernema species contained two different hsp-90 genes and the main difference was the intron presence-absence between hsp-90 genes. The hsp-9o genes containing introns showed conserved intron position between them with high sequence variation. This study showed, for the first time, the presence of two different isoforms for the hsp-90 in nematodes and the conserved position of the intron between the three Steinernema species. Further investigations are ongoing in order to characterize thermotolerant strains.