Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/29/2008
Publication Date: 6/26/2008
Citation: Lu, S., Wang, J., Chen, S., Yu, H., Mitchum, M.G., Wang, X. 2008. Functional characterization of CLE peptides from a plant-parasitic nematode Globodera rostochiensis. American Society of Plant Biologists Annual Meeting. p. 55.
Technical Abstract: Plant CLAVATA3/ESR (CLE) proteins are a large family of secreted peptide ligands that play important roles in plant growth and development. Recent evidence suggests that plant-parasitic cyst nematodes secrete ligand mimics of plant CLE peptides to modify selected host root cells into multinucleate feeding sites. Parasitism genes encoding CLE-like peptides were cloned from the potato cyst nematode, Globodera rostochiensis and found to be expressed in the nematode’s dorsal esophageal gland cell during feeding site initiation and maintenance. Gene structure analysis grouped Gr-CLE genes into two major classes, Gr-CLE-1 and Gr-CLE-4, in which Gr-CLE-4 was confirmed to have multiple copies in the genome. Interestingly, unlike most plant CLEs and the nematode CLEs of the genus Heterodera, members of the G. rostochiensis CLE peptide family were found to contain multiple CLE domains. Overexpression of either Gr-CLE-1 or Gr-CLE-4 in Arabidopsis under the control of the CaMV35S promoter produced phenotypes resembling those produced by plant CLEs including wuschel-like seedlings, generation of wuschel flowers, short roots, anthocyanin accumulation, delayed development, and seedling death. In vitro application of synthetic 12-amino acid peptides, corresponding to the CLE motifs of Gr-CLE-1 and Gr-CLE-4, to the roots of Arabidopsis, tomato, and potato caused a short root phenotype. Transient expression of the full-length Gr-CLE-1 gene as a C-terminal tagged protein in Nicotiana benthamiana leaves revealed that Gr-CLE-1 was processed into different forms of potentially membrane-bound proteins. Our studies suggest that this novel class of nematode CLEs has functional similarity to plant CLE signaling peptides and highlights an important role for ligand mimicry in plant parasitism by G. rostochiensis.