Cloning and characterisation of a Heterodera glycines aminopeptidase cDNA

An aminopeptidase full-length cDNA (Hg-amp-1) was cloned from the adult female soybean cyst nematode Heterodera glycines by heterologous screening of a cDNA library with a Caenorhabditis elegans EST sequence. The predicted open reading frame encoded an 882-amino acid protein containing the conserved zinc-binding domain and GAMEN motif that are characteristic of M1 family aminopeptidases. The putative protein lacks any subcellular targeting signals and displays strong similarity to puromycin-sensitive aminopeptidases from C. elegans, Drosophila and mammals. Hg-amp-1 is expressed in juvenile nematodes and both male and female adults, with highest expression in gravid females. In situ mRNA hybridisation localised the Hg-amp-1 transcript to the genital primordium of pre-parasitic juvenile nematodes and the reproductive tract of adult females. Suppression of Hg-amp-1 transcript level by RNA-interference led to a 61% reduction in the number of female nematodes parasitising soybean roots 21 days post infection with infective juvenile nematodes that had been exposed to double-stranded RNA.