MOLECULAR CHARACTERIZATION OF A SOYBEAN CYST NEMATODE HOMOLOGY OF UNC-87.

Authors: Matthews, Benjamin; Pilitt, Kristina; Klink, Vincent

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2004
Publication Date: 7/30/2004
Citation: Matthews, B.F., Pilitt, K.L., Klink, V.P. 2004. Molecular characterization of a soybean cyst nematode homology of unc-87. Journal of Nematology 36: 457-465.

Interpretive Summary: The soybean cyst nematode causes an estimated one billion dollars in losses each year in the U.S. To feed, the soybean cyst nematode must be able to provide its own locomotion to move to a soybean root and burrow inside. A gene, unc-87, encodes a protein involved in the structure of body muscle and is necessary for movement. In another nematode, Caenorhabditis elegans, mutants of this gene exhibit severe paralysis in larvae and limp paralysis in the adult. We cloned and characterized a full-length unc-87 gene of the soybean cyst nematode and studied the expression of this gene. It was expressed 8-fold higher in the nematode's mobile juvenile form than in eggs and over two hundred-fold and four hundred-fold higher than in sedentary nematodes 15- and 30-days after penetrating the root. This gene is a possible target for nematode control. Disrupting the expression of this gene will inhibit nematode movement, thus compromising a necessary nematode function, culminating in nematode death. This information is of interest to scientists studying ways to prevent the nematodes from moving to and entering roots.

Technical Abstract: In Caenorhabditis elegans the unc-87 gene encodes a protein that binds to actin at the I band and is important in nematodes for maintenance of the body-wall muscle. C. elegans mutant phenotypes of unc-87 in exhibit severe paralysis in larvae and limp paralysis in the adult. The unc-87 gene encodes a protein that contains seven CLIK-23 repeats that are involved in binding actin and UNC-87 has the ability to bundle actin in vitro. We cloned and characterized a full-length cDNA representing a Heterodera glycines homolog of the C. elegans unc-87 gene encodes a protein that contains a region of seven repeats similar to CLIK-23 and has 81% amino acid identity with that of C. elegans unc-87 variant a. In the EST database clones labeled 'unc-87 ' encode mainly the 3' portion of unc-87, while clones labeled 'calponin homolog OV9M' contain mainly DNA sequence representing the 5' and middle transcribed regions of unc-87. A 1770 nt cDNA encoding H. glycines unc-87 was cloned and encodes a predicted UNC-87 protein product of 375 aa. PCR primers were designed that amplified products of different sizes when used with cDNA and genomic DNA, respectively, used as template, thus these primers can be used to assay for genomic contamination of cDNA constructed from H. glycines RNA for RT-PCR measurements of gene expression. The expression of unc-87 was determined using RT-PCR and it was most highly expressed in J2 juveniles and was expressed 10-higher than in eggs and over two thousand-fold and six thousand-fold higher in nematodes 15- and 30-days after inoculation. This gene is a possible target for nematode control by disrupting the expression of this gene, which will inhibit nematode movement, thus compromising a necessary nematode function, culminating in nematode death. This information is of interest to scientists studying ways to prevent the nematodes from moving to and entering roots.