Characterisation of guanylyl cyclase genes in the soybean cyst nematode, Heterodera glycines

• Published in: International journal for parasitology Vol. 32; no. 1; pp. 65 - 72
• Main Authors: YITANG YAN, DAVIS, Eric L
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Science 2002
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; DNA, Helminth - chemistry; DNA, Helminth - genetics; DNA, Helminth - isolation & purification; Fundamental and applied biological sciences. Psychology; Glycine max - parasitology; Guanylate Cyclase - chemistry; Guanylate Cyclase - genetics; guanylyl cyclase; Heterodera glycines; HG-gcy-1 gene; HG-gcy-2 gene; HG-gcy-3 gene; Host parasite relation; pathogenicity; In Situ Hybridization; Invertebrates; Isoenzymes - chemistry; Isoenzymes - genetics; Molecular Sequence Data; Nemathelminthia. Plathelmintha; Nematoda - enzymology; Nematoda - genetics; Polymerase Chain Reaction; RNA, Messenger - chemistry; Sequence Homology, Amino Acid; Host parasite relation; Genome organization; Plant pathogen; Enzyme; Phosphorus-oxygen lyases; Parasite; Lyases; Chemoreception; Sensory receptor; Gene expression; Guanylate cyclase; Glycine max; Grain legume; Heterodera glycines; Leguminosae; Complementary DNA; Dicotyledones; Angiospermae; Helmintha; Nemathelminthia; Spermatophyta; Invertebrata; Nematoda; Aminoacid sequence
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/S0020-7519(01)00315-0

Parasitism by the soybean cyst nematode, Heterodera glycines, has become one of the major limiting factors in soybean production world-wide. A partial HG-gcy-1 cDNA clone was obtained by screening a H. glycines cDNA library with a probe derived from the HG-gcy1 genomic sequence, and HG-gcy-1 full-length cDNA was obtained by nested PCR and 5' rapid amplification of cDNA ends (5' RACE). Two additional, full-length guanylyl cyclase cDNA clones from H. glycines, named HG-gcy-2 and HG-gcy-3, were recovered directly by screening the H. glycines cDNA library with a probe derived from sequence of the HG-gcy-1 catalytic domain. The encoded proteins of all three HG-gcy genes had an extracellular ligand-binding domain, a single membrane-spanning domain, an intracellular protein kinase-like domain, and a guanylyl cyclase catalytic domain. The three HG-GCY proteins had conserved cysteine residues to form disulfide bridges within the extracellular domain similar to the predicted ligand-binding domains of other known membrane-bound guanylyl cyclases. mRNA in situ hybridisation detected the expression of HG-gcy-1 and HG-gcy-2 transcripts in specific and different sensory neurons within H. glycines specimens. HG-gcy-3 transcripts were not localised in H. glycines specimens by in situ hybridisation. The discovery of the three guanylyl cyclase genes in H. glycines is the first of its kind in a plant-parasitic nematode and may be representative of a conserved gene family used for chemosensory recognition in parasitic nematodes.