title: Cathepsin B Cysteine Proteinase is Essential for the Development and Pathogenesis of the Plant Parasitic Nematode Radopholus similis.
abstract: Radopholus similis is an important plant parasitic nematode which severely harms many crops. Cathepsin B is present in a wide variety of organisms, and plays an important role in many parasites. Understanding cathepsin B of R. similis would allow us to find new targets and approaches for its control. In this study, we found that Rs-cb-1 mRNA was expressed in esophageal glands, intestines and gonads of females, testes of males, juveniles and eggs in R. similis. Rs-cb-1 expression was the highest in females, followed by juveniles and eggs, and was the lowest in males. The maximal enzyme activity of Rs-CB-1 was detected at pH 6.0 and 40 °C. Silencing of Rs-cb-1 using in vitro RNAi (Soaking with dsRNA in vitro) not only significantly inhibited the development and hatching of R. similis, but also greatly reduced its pathogenicity. Using in planta RNAi, we confirmed that Rs-cb-1 expression in nematodes were significantly suppressed and the resistance to R. similis was significantly improved in T2 generation transgenic tobacco plants expressing Rs-cb-1 dsRNA. The genetic effects of in planta RNAi-induced gene silencing could be maintained in the absence of dsRNA for at least two generations before being lost, which was not the case for the effects induced by in vitro RNAi. Overall, our results first indicate that Rs-cb-1 plays key roles in the development, hatching and pathogenesis of R. similis, and that in planta RNAi is an effective tool in studying gene function and genetic engineering of plant resistance to migratory plant parasitic nematodes.
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Dong-Wei
authors.initials: DW
authors.lastname: Wang
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Chun-Ling
authors.initials: CL
authors.lastname: Xu
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.affiliation: 1. Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Department of Plant Pathology, South China Agricultural University, Guangzhou 510642, China;
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Wu
authors.affiliation: 2. College of Forestry, Northeast Forestry University, Haerbin 150040, China.
authors.forename: Dan-Lei
authors.initials: DL
authors.lastname: Li
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000378:metabolism*; D057056:Cysteine Proteases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008297:Male; D009348:Nematoda / Q000201:enzymology* / Q000472:pathogenicity*; D030821:Plants, Genetically Modified / Q000469:parasitology; D034622:RNA Interference / Q000502:physiology; D014026:Nicotiana / Q000469:parasitology
chemical_list: D057056:Cysteine Proteases; D002401:Cathepsin B
keywords: Cathepsin B; RNAi; Radopholus similis; development; pathogenesis; transgenic tobacco