Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/14/2008
Publication Date: 6/26/2008
Citation: Replogle, A., Wang, J., Wang, X., Davis, E.L., Mitchum, M.G. 2008. Root Growth Response to Application and Overexpression of Heterodera glycines CLE peptides. Phytopathology. 98:S132.
Technical Abstract: Plant CLAVATA3/ESR(CLE)-like peptides have been shown to be involved with several aspects of plant development including maintenance of stem cell pools in the root meristem. Interestingly, parasitism genes, HgCLE-1 and HgCLE-2, encoding secreted CLE-like peptides are expressed in the dorsal esophageal gland cell of the soybean cyst nematode (SCN), Heterodera glycines, during syncytium induction and maintenance in host roots. HgCLE-1 and HgCLE-2, differ only in a variable domain N-terminal of the conserved CLE motif. Deletion of the CLE motif abolishes function in overexpression studies, and exogenous application of a synthetic dodecapeptide corresponding to the conserved CLE motif of HgCLEs is sufficient to induce a short root phenotype when applied to Arabidopsis roots. Despite their identical CLE motifs, constitutive overexpression of HgCLE-1 but not HgCLE-2 in Arabidopsis, a non-host for SCN induced root meristem defects similar to that of overexpression of plant CLEs. In constrast, when overexpressed in soybean hairy roots, a host for SCN, both HgCLE-1 and HgCLE-2 caused premature termination of primary root growth. Cell identity marker lines combined with confocal microscopy are being used to assess affects of nematode CLE peptides on root growth. These data suggest that there may be host-specific control of nematode CLE peptide recognition. This indicates that the evolution of nematode CLE genes could explain one of the underlying mechanisms driving the specific adaptation of cyst nematodes to parasitize particular host plant species.