Molecular characterization of CLE peptide mimicry during cyst nematode pathogenesis

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Plant-parasitic cyst nematodes establish intimate parasitic relationships with their hosts by penetrating the root as motile juveniles and migrating intracellularly until they reach the root vasculature where they select a single cell to initiate a feeding site known as the syncytium. It has been proposed that the development and maintenance of the syncytium is dependent on secretory effector proteins originating in the esophageal gland cells and delivered into the host root through the nematode stylet. Several effector proteins from cyst nematodes have been identified as CLAVATA3 (CLV3)/ESR (CLE)-like proteins. Due to the different roles plant CLE peptides play in promoting differentiation, we hypothesize that nematode CLEs mimic plant CLEs to help initiate and maintain feeding sites. In this study, we show that nematode CLEs act as ligand mimics of plant CLE peptides and are required for successful nematode infection. In addition, by analyzing the involvement of known CLE receptors in Arabidopsis during infection by the beet cyst nematode Heterodera schachtii, we identified a role for CLV1, CLV2, CRN, RPK2, and BAM1 in nematode CLE perception and proper formation of the syncytium. Ongoing studies will utilize laser capture microdissection coupled with mRNA-Seq to identify downstream signaling cascades after nematode CLE perception. The results of these studies will contribute to our understanding of how plant-parasitic nematodes interact with their host plants on a molecular level, and could open up possibilities to develop biotech approaches to control cyst nematodes.