title: Exposure to double-stranded RNA mediated by tobacco rattle virus leads to transcription up-regulation of effector gene Mi-vap-2 from Meloidogyne incognita and promotion of pathogenicity in progeny.
abstract: Meloidogyne spp. are economically important plant parasites and cause enormous damage to agriculture world-wide. These nematodes use secreted effectors which modify host cells, allowing them to obtain the nutrients required for growth and development. A better understanding of the roles of effectors in nematode parasitism is critical for understanding the mechanisms of nematode-host interactions. In this study, Mi-vap-2 of Meloidogyne incognita, a gene encoding a venom allergen-like protein, was targeted by RNA interference mediated by the tobacco rattle virus. Unexpectedly, compared with a wild type line, a substantial up-regulation of Mi-vap-2 transcript was observed in juveniles collected at 7 days p.i. from Nicotiana benthamiana agroinfiltrated with TRV::vap-2. This up-regulation of the targeted transcript did not impact development of females or the production of galls, nor the number of females on the TRV::vap-2 line. In a positive control line, the transcript of Mi16D10 was knocked down in juveniles from the TRV::16D10 line at 7 days p.i., resulting in a significant inhibition of nematode development. The up-regulation of Mi-vap-2 triggered by TRV-RNAi was inherited by the progeny of the nematodes exposed to double-stranded RNA. Meanwhile, a substantial increase in Mi-VAP-2 expression in those juvenile progeny was revealed by ELISA. This caused an increase in the number of galls (71.2%) and females (84.6%) produced on seedlings of N. benthamiana compared with the numbers produced by control nematodes. Up-regulation of Mi-vap-2 and its encoded protein therefore enhanced pathogenicity of the nematodes, suggesting that Mi-vap-2 may be required for successful parasitism during the early parasitic stage of M. incognita.
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Yuankai
authors.initials: Y
authors.lastname: Chi
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xiuhu
authors.initials: X
authors.lastname: Le
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Ju
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Tinglong
authors.initials: T
authors.lastname: Guan
authors.affiliation: Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: lihm@njau.edu.cn.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Li
mesh_terms: D000818:Animals; D005260:Female; D017238:Genes, Helminth; D008297:Male; D010942:Plant Viruses / Q000235:genetics; D034622:RNA Interference; D012328:RNA Viruses / Q000235:genetics; D012330:RNA, Double-Stranded; D012367:RNA, Viral; D014026:Nicotiana / Q000469:parasitology / Q000821:virology; D014431:Tylenchoidea / Q000235:genetics* / Q000472:pathogenicity; D015854:Up-Regulation
chemical_list: D012330:RNA, Double-Stranded; D012367:RNA, Viral
keywords: ELISA; Meloidogyne incognita; Pathogenicity; RNA interference; Relative transcript level; Tobacco rattle virus; Venom allergen-like protein