Similarity and functional analyses of expressed parasitism genes in Heterodera schachtii and Heterodera glycines

The secreted proteins encoded by "parasitism genes" expressed within the esophageal gland cells of cyst nematodes play important roles in plant parasitism. Homologous transcripts and encoded proteins of the Heterodera glycines pioneer parasitism genes Hgsyv46, Hg4e02 and Hg5d08 were identified and similarly expressed within the esophageal glands cells of Heterodera schachtii. Constitutive expression of Hs4E02 and Hs5D08 in transgenic Arabidopsis thaliana did not produce any visible phenotypic changes in plant growth and development nor affect the number of H. schachtii females that developed on roots of those plants. Constitutive and nematode-inducible Arabidopsis expression of double-stranded RNA complementary to Hssyv46, a parasitism gene with function similar to plant CLAVATA3/ESR peptides, resulted in a significant (P ≤ 0.05) 36% decrease in H. schachtii female numbers and significant host-derived RNA interference-mediated silencing of Hssyv46 transcript levels in nematodes excised from those roots. Significant and specific effects of Arabidopsis host-derived RNAi complementary to Hs5d08 or Hs4e02 on H. schachtii female development were not observed, however, up to 20% reduction in H. schachtii female numbers were observed in roots of these plants.