A Nematode Calreticulin, Rs-CRT, Is a Key Effector in Reproduction and Pathogenicity of Radopholus similis

• Published in: PloS one 2015-06, Vol.10 (6), p.e0129351-e0129351
• Main Authors: Li, Yu, Wang, Ke, Xie, Hui, Wang, Yan-Tao, Wang, Dong-Wei, Xu, Chun-Lin, Huang, Xin, Wang, De-Sen
• Format: Article
• Language: English
• Subjects: Agricultural pests; Amino acids; Animal parasites; Animals; Calcium; Calcium ions; Calreticulin; Calreticulin - genetics; Calreticulin - metabolism; Cloning; Cloning, Molecular; Double-stranded RNA; Eggs; Esophagus; Female; Females; Genes; Genetic engineering; Genomics; Glands; Gonads; Horticultural crops; Intestine; Laboratories; Male; Males; Meloidogyne incognita; Nematodes; Parasites; Parasitic diseases; Parasitism; Pathogenesis; Pathogenicity; Pathogens; Phylogeny; Plant Diseases - parasitology; Plant pathology; Protein binding; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Quarantine; R&D; Radopholus similis; Reproduction; Research & development; RNA-mediated interference; Roundworms; Seeds; Sequence Homology; Solanum lycopersicum - genetics; Solanum lycopersicum - growth & development; Solanum lycopersicum - parasitology; Tomatoes; Transgenic plants; Tylenchoidea - pathogenicity; Tylenchoidea - physiology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0129351

Radopholus similis is a migratory plant-parasitic nematode that causes severe damage to many agricultural and horticultural crops. Calreticulin (CRT) is a Ca2+-binding multifunctional protein that plays key roles in the parasitism, immune evasion, reproduction and pathogenesis of many animal parasites and plant nematodes. Therefore, CRT is a promising target for controlling R. similis. In this study, we obtained the full-length sequence of the CRT gene from R. similis (Rs-crt), which is 1,527-bp long and includes a 1,206-bp ORF that encodes 401 amino acids. Rs-CRT and Mi-CRT from Meloidogyne incognita showed the highest similarity and were grouped on the same branch of the phylogenetic tree. Rs-crt is a multi-copy gene that is expressed in the oesophageal glands and gonads of females, the gonads of males, the intestines of juveniles and the eggs of R. similis. The highest Rs-crt expression was detected in females, followed by juveniles, eggs and males. The reproductive capability and pathogenicity of R. similis were significantly reduced after treatment with Rs-crt dsRNA for 36 h. Using plant-mediated RNAi, we confirmed that Rs-crt expression was significantly inhibited in the nematodes, and resistance to R. similis was significantly improved in transgenic tomato plants. Plant-mediated RNAi-induced silencing of Rs-crt could be effectively transmitted to the F2 generation of R. similis; however, the silencing effect of Rs-crt induced by in vitro RNAi was no longer detectable in F1 and F2 nematodes. Thus, Rs-crt is essential for the reproduction and pathogenicity of R. similis.