Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/2006
Publication Date: 8/1/2006
Citation: Wang, J., Replogle, A., Wang, X., Davis, E., Mitchum, M. 2006. Functional analysis of nematode secreted CLAVATA3/ESR (CLE)-like peptides of the genus Heterodera [abstract]. Phytopathology. 96:S120.
Technical Abstract: Cyst nematodes of the genus Heterodera are obligate, sedentary endoparasites that have developed highly evolved relationships with specific host plant species. We have identified two H. glycines CLAVATA3/ESR(CLE)-like genes, HgCLEA and HgCLEB, that encode secreted peptides with similarity to plant CLE peptides involved in mediating various plant developmental processes. The predicted peptides differ in a highly variable domain outside of the conserved CLE motif. Significant CLE sequence variation within populations of the nematode, differing in virulence characteristics on resistant soybean, suggests that these effectors may be co-evolving with the host. Overexpression of HgCLEA in Arabidopsis, a nonhost for H. glycines, resulted in a range of wus-like phenotypes distinct from overexpression of HgCLEB. We are currently investigating possible gene duplication followed by functional divergence in H. glycines by characterizing soybean hairy roots overexpressing HgCLEs. Overexpression of CLE genes isolated from H. schachtii, a close relative of H. glycines that can successfully infect Arabidopsis, caused more severe phenotypes than HgCLEs. Our studies provide further evidence of an important role for ligand mimicry in nematode parasitism and suggest that this may be a mechanism involved in cyst nematode adaptation to particular host plants.