title: The Role of Cytokinin During Infection of Arabidopsis thaliana by the Cyst Nematode Heterodera schachtii.
abstract: Plant-parasitic cyst nematodes induce the formation of hypermetabolic feeding sites, termed syncytia, as their sole source of nutrients. The formation of the syncytium is orchestrated by the nematode, in part, by modulation of phytohormone responses, including cytokinin. In response to infection by the nematode Heterodera schachtii, cytokinin signaling is transiently induced at the site of infection and in the developing syncytium. Arabidopsis lines with reduced cytokinin sensitivity show reduced susceptibility to nematode infection, indicating that cytokinin signaling is required for optimal nematode development. Furthermore, lines with increased cytokinin sensitivity also exhibit reduced nematode susceptibility. To ascertain why cytokinin hypersensitivity reduces nematode parasitism, we examined the transcriptomes in wild type and a cytokinin-hypersensitive type-A arr Arabidopsis mutant in response to H. schachtii infection. Genes involved in the response to biotic stress and defense response were elevated in the type-A arr mutant in the absence of nematodes and were hyperinduced following H. schachtii infection, which suggests that the Arabidopsis type-A arr mutants impede nematode development because they are primed to respond to pathogen infection. These results suggest that cytokinin signaling is required for optimal H. schachtii parasitism of Arabidopsis but that elevated cytokinin signaling triggers a heightened immune response to nematode infection.
authors.affiliation: 1 Department of Biology, University of North Carolina, Chapel Hill, NC 27599, U.S.A.;
authors.forename: Carly M
authors.initials: CM
authors.lastname: Shanks
authors.affiliation: 2 Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, U.S.A.;
authors.forename: J Hollis
authors.initials: JH
authors.lastname: Rice
authors.affiliation: 3 Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, U.S.A.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zubo
authors.affiliation: 3 Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, U.S.A.
authors.forename: G Eric
authors.initials: GE
authors.lastname: Schaller
authors.affiliation: 2 Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, U.S.A.;
authors.forename: Tarek
authors.initials: T
authors.lastname: Hewezi
authors.affiliation: 1 Department of Biology, University of North Carolina, Chapel Hill, NC 27599, U.S.A.;
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Kieber
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000378:metabolism* / Q000469:parasitology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism*; D004198:Disease Susceptibility; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000378:metabolism; D009154:Mutation; D009348:Nematoda / Q000502:physiology*; D010935:Plant Diseases / Q000469:parasitology*; D018517:Plant Roots / Q000378:metabolism / Q000469:parasitology; D015398:Signal Transduction / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D049452:Green Fluorescent Proteins