Submitted to: BioMed Central Developmental Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/6/2006
Publication Date: 9/6/2006
Citation: Martins, V., Klink, V.P., Alkharouf, N., Macdonald, M.H., Matthews, B.F. 2006. A decline in transcript abundance for Heterodera glycines homolog Caenorhabditis elegans uncoordinated genes accompanies its sedentary parasitic phase.. BioMed Central Developmental Biology. 7(35):1-11. Interpretive Summary: The soybean cyst nematode is the most destructive pest of soybean in the U.S., causing an estimated $700 million in damage each year. Although some soybeans are resistant to certain isolates of soybean cyst nematode, broad resistance is needed in soybean to the wide variety of soybean cyst nematodes found in a field population. We identified and cloned a gene of the soybean cyst nematode that may be important to survival of the nematode. This gene, named unc-97, is involved in muscle function. Disruption of this gene may cause paralysis and stop the nematode from completing its life cycle. This information is of use to scientists examining nematodes and attempting to develop new modes of nematode control using molecular approaches.
Technical Abstract: The soybean cyst nematode (SCN) is the major pest of soybean in the United States and no agronomically important soybean cultivars are resistant to all races of SCN. Our major goal is to develop new modes of soybean resistance to SCN using biotechnology. Therefore, we identified and characterized the SCN (Heterodera glycines) homolog of the Caenorhabditis elegans unc-97 gene (Hg-unc97), a gene that may be essential for SCN survival. In C. elegans the unc-97 gene encodes a protein involved in movement that constitutes a component of the muscular adherens junction by interacting with the '-integrin PAT-3 at the focal adhesion-like attachment sites of muscles. In C. elegans, mutants of unc-97 are limp, egg laying-defective and paralyzed. We identified a SCN partial cDNA clone, Hg-unc97, with high amino acid identity to C. elegans unc-97 and used PCR to obtain the full-length Hg-unc97 gene. The Hg-unc-97 cDNA is 1567 nt, encoding a 521 aa protein. Phylogenetic analysis of the full-length sequence revealed 63% amino acid identity with C. elegans unc-97. Real-time reverse transcription polymerase chain reaction (RT-PCR) indicated that Hg-unc97 is expressed in all stages of the SCN lifecycle. The relative ratios of Hg-unc97 between the different time points in the life cycle obtained by RT-PCR indicated a 6-fold increase in Hg-unc97 RNA in J2s, respective to eggs, and nematodes 15 and 30-day post infection. The use of the Hg-unc-97 to broaden resistance of soybean to SCN will be tested in future experiments.