Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2013
Publication Date: 7/14/2013
Citation: Gavilano, L., Baum, T.J., Parrott, W.A., Davis, E.L., Wubben, M. 2013. Identification and characterization of a CLE domain-containing protein from Rotylenchulus reniformis. Proceedings Society of Nematologists, July 14-17, 2013, Knoxville, TN. CD ROM. Interpretive Summary:
Technical Abstract: The reniform nematode, Rotylenchulus reniformis, is a sedentary semi-endoparasite that causes significant yield loss on many economically important crops including cotton, soybean, and pineapple. Vermiform infective female nematodes secrete esophageal gland effector proteins, encoded by parasitism genes, into or in proximity to the root cells of their host inducing the formation of a multinucleate nurse cell system known as a syncytium. The identification and characterization of these secreted effector proteins and their respective genes are important for the development of alternative management strategies based on parasitism gene silencing via RNA-interference (RNAi). In this study, we report the isolation and characterization of a full-length candidate parasitism gene isolated from reniform nematode. The isolated gene, designated Rr-cle-1, belongs to the CLE (CLAVATA3/ESR-related) domain-containing family of nematode effector proteins. The Rr-cle-1 cDNA contains an open reading frame of 405 bp that encodes a predicted peptide of 134 amino acids (Rr-CLE-1). Rr-CLE-1 contains a single CLE domain at its C-terminal end and a N-terminal signal peptide. The expression of Rr-cle-1 was confirmed in all reniform nematode stages by RT-PCR and cDNA sequencing; however, transcript levels were greatest in sedentary parasitic females. According to BLASTp analysis, the CLE domain of Rr-cle-1 showed 83% identity to Oryza sativa CLE domain and less than 32% amino acid identity to Heterodera schachtii and H. glycines. In situ hybridization of Rr-cle-1 transcripts demonstrated exclusive high level expression in the dorsal esophageal gland cells of R. reniformis sedentary females. All vermiform life stages were negative for Rr-cle-1 transcript using in situ hybridization. Previous studies involving Heterodera and Globodera spp. have demonstrated that RNAi-mediated silencing of CLE parasitism genes significantly reduced nematode reproduction, thereby, lending themselves as potential targets for nematode control. Rr-cle-1 gene manipulation toward developing resistant soybean plants via RNAi is currently in progress.