title: Knocking-down Meloidogyne incognita proteases by plant-delivered dsRNA has negative pleiotropic effect on nematode vigor.
abstract: The root-knot nematode Meloidogyne incognita causes serious damage and yield losses in numerous important crops worldwide. Analysis of the M. incognita genome revealed a vast number of proteases belonging to five different catalytic classes. Several reports indicate that M. incognita proteases could play important roles in nematode parasitism, besides their function in ordinary digestion of giant cell contents for feeding. The precise roles of these proteins during parasitism however are still unknown, making them interesting targets for gene silencing to address protein function. In this study we have knocked-down an aspartic (Mi-asp-1), a serine (Mi-ser-1) and a cysteine protease (Mi-cpl-1) by RNAi interference to get an insight into the function of these enzymes during a host/nematode interaction. Tobacco lines expressing dsRNA for Mi-ser-1 (dsSER), Mi-cpl-1 (dsCPL) and for the three genes together (dsFusion) were generated. Histological analysis of galls did not show clear differences in giant cell morphology. Interestingly, nematodes that infected plants expressing dsRNA for proteases produced a reduced number of eggs. In addition, nematode progeny matured in dsSER plants had reduced success in egg hatching, while progeny resulting from dsCPL and dsFusion plants were less successful to infect wild-type host plants. Quantitative PCR analysis confirmed a reduction in transcripts for Mi-cpl-1 and Mi-ser-1 proteases. Our results indicate that these proteases are possibly involved in different processes throughout nematode development, like nutrition, reproduction and embryogenesis. A better understanding of nematode proteases and their possible role during a plant-nematode interaction might help to develop new tools for phytonematode control.
authors.affiliation: Graduate Program in Biology Molecular, Universidade de Brasília, Brasília, Distrito Federal, Brazil ; Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: José Dijair
authors.initials: JD
authors.lastname: Antonino de Souza Júnior
authors.affiliation: Graduate Program in Biology Molecular, Universidade de Brasília, Brasília, Distrito Federal, Brazil ; Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Roberta
authors.initials: R
authors.lastname: Ramos Coelho
authors.affiliation: Graduate Program in Biology Molecular, Universidade de Brasília, Brasília, Distrito Federal, Brazil ; Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Isabela
authors.initials: I
authors.lastname: Tristan Lourenço
authors.affiliation: Embrapa Cerrados, Planaltina, Ditrito Federal, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: da Rocha Fragoso
authors.affiliation: Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, Brasília, Distrito Federal, Brazil.
authors.forename: Antonio Américo
authors.initials: AA
authors.lastname: Barbosa Viana
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Lima Pepino de Macedo
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Mattar da Silva
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil.
authors.forename: Regina Maria
authors.initials: RM
authors.lastname: Gomes Carneiro
authors.affiliation: Institut National de la Recherche Agronomique, UMR 1355 ISA/Centre National de la Recherche Scientifique, UMR 7254 ISA/Université de Nice-Sophia Antipolis, UMR ISA, Sophia-Antipolis, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Engler
authors.affiliation: Institut National de la Recherche Agronomique, UMR 1355 ISA/Centre National de la Recherche Scientifique, UMR 7254 ISA/Université de Nice-Sophia Antipolis, UMR ISA, Sophia-Antipolis, France.
authors.forename: Janice
authors.initials: J
authors.lastname: de Almeida-Engler
authors.affiliation: Embrapa Recursos Genéticos e Biotecnologia, Brasília, Distrito Federal, Brazil ; Graduate Program in Genomic Sciences and Biotechnology, Universidade Católica de Brasília, Brasília, Distrito Federal, Brazil.
authors.forename: Maria Fatima
authors.initials: MF
authors.lastname: Grossi-de-Sa
mesh_terms: D000818:Animals; D001483:Base Sequence; D003198:Computer Simulation; D020224:Expressed Sequence Tags; D005260:Female; D055785:Gene Knockdown Techniques; D010063:Ovum / Q000254:growth & development / Q000378:metabolism; D010447:Peptide Hydrolases / Q000172:deficiency* / Q000235:genetics*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics*; D014431:Tylenchoidea / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D010447:Peptide Hydrolases