Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/2007
Publication Date: 7/7/2007
Citation: Wang, J., Peplogle, A., Wang, X., Davis, E.L., Mitchum, M. 2007. Functional characterization of plant-parasitic cyst nematode CLE peptides. Plant Biology Annual Meeting.
Technical Abstract: During root infection by plant-parasitic cyst nematodes, proteins originating in gland cells are secreted through the stylet into a cell near the vasculature of the host root for the initiation and maintenance of a specialized feeding structure (syncytium). Soybean cyst nematode (SCN; Heterodera glycines) genes coding for secreted CLAVATA3/ESR (CLE)-like signaling peptides were identified. CLV3, the founding member of a 31 member CLE peptide family in Arabidopsis, plays an important role in controlling the balance between shoot meristem cell proliferation and differentiation by signaling through the CLAVATA1 (CLV1)/CLAVATA2 (CLV2) receptor complex. Two predominant SCN CLE forms, HgCLEA and HgCLEB, share an identical CLE domain and are highly induced at the onset of parasitism. Overexpression of HgCLEA, not HgCLEB in Arabidopsis under control of the CaMV35S promoter results in shoot and floral meristem defects similar to that of overexpression of CLV3, and the severity of defect correlates with expression level of the transgene. Roots of overexpression lines exhibit premature termination of the primary root meristem. Similarly, exogenous application of a synthetic peptide corresponding to the CLE motif of HgCLE suppresses the growth of primary roots. Homologous sequences with unique CLE domains have been identified from the sugar beet cyst nematode (H. schachtii), a close relative of SCN that can successfully infect Arabidopsis. Overexpression of HsCLEs in Arabidopsis results in more severe phenotypes than that of HgCLEs. These studies provide further evidence that nematode CLEs may play a key role to developmentally reprogram the fate of selected plant cells for syncytium development by ligand mimicry of plant signaling peptides.