title: Additive effects of plant expressed double-stranded RNAs on root-knot nematode development.
abstract: Ectopically expressed double-stranded RNAs (dsRNAs) have recently been shown to suppress parasitic success of Meloidogyne spp. in plants. We have targeted two genes from the root-knot nematode Meloidogyne incognita; a dual oxidase gene implicated in the tyrosine cross-linking of the developing cuticle and a subunit of signal peptidase, a protein complex required for the processing of secreted proteins. While these genes are involved in different aspects of nematode development, the phenotypic consequences of RNA interference (RNAi) were similar with >or=50% reduction in nematode numbers in the roots and retardation of development to the egg-producing saccate females. Expression of processed dsRNA was observed, but no evidence of detectable levels of small interfering RNAs (siRNAs) was found in the transgenic plants. We show, to our knowledge for the first time, that combining expression of these dsRNAs by crossing appropriate Arabidopsis thaliana lines resulted in an additive effect that further reduced nematode numbers and developmental capacity. Combining RNAi target genes has the potential to enhance the efficacy of RNAi and may allow control of different nematode species or genera in the crop of interest.
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Charlton
authors.forename: H Yael Meller
authors.initials: HY
authors.lastname: Harel
authors.forename: Manjula
authors.initials: M
authors.lastname: Bakhetia
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Hibbard
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Atkinson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McPherson
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000469:parasitology*; D005260:Female; D015801:Helminth Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics; D010935:Plant Diseases / Q000469:parasitology; D018517:Plant Roots / Q000469:parasitology*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D018510:RNA, Helminth / Q000096:biosynthesis* / Q000235:genetics; D034741:RNA, Small Interfering / Q000096:biosynthesis* / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics; D014431:Tylenchoidea / Q000254:growth & development*
chemical_list: D015801:Helminth Proteins; D008565:Membrane Proteins; D018510:RNA, Helminth; D034741:RNA, Small Interfering; D019255:NADPH Oxidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase