Plant CLAVATA3/ESR-related (CLE) peptides have diverse roles in plant growth and development. We have isolated and characterized the function of five new CLE genes from the potato cyst nematode Globodera rostochiensis. Unlike typical plant CLEs that contain a single CLE motif, four of the five Gr-CLE genes encode CLE proteins with multiple CLE motifs. These Gr-CLEs were found to be specifically expressed within the dorsal esophageal gland cell of nematode parasitic stages, suggesting a role for their encoded proteins in plant parasitism. Overexpression of Gr-CLEs in Arabidopsis mimicked overexpression of plant CLEs and Gr-CLE proteins could rescue the Arabidopsis clv3-2 mutant phenotype when expressed within meristems. A short root phenotype was observed when synthetic GrCLE peptides were exogenously applied to roots of Arabidopsis or potato similar to the overexpression of Gr-CLEs in Arabidopsis and potato hairy roots. These results reveal that G. rostochiensis CLEs with either single or multiple CLE motifs function similarly to plant CLEs and that CLE signaling components are conserved in both Arabidopsis and potato roots. Transgenic potato hairy roots expressing Gr-CLE-1 or Gr-CLE-4 dsRNA were generated. There was an approximately 50% reduction in the average number of cysts per root in the Gr-CLE-1 or Gr-CLE-4 dsRNA transgenic lines when compared with the infected control lines, indicating that silencing nematode CLE genes through host-derived RNAi may generate novel resistance against potato cyst nematodes in transgenic potatoes.
