title: Getting ready for host invasion: elevated expression and action of xyloglucan endotransglucosylases/hydrolases in developing haustoria of the holoparasitic angiosperm Cuscuta.
abstract: Changes in cell walls have been previously observed in the mature infection organ, or haustorium, of the parasitic angiosperm Cuscuta, but are not equally well charted in young haustoria. In this study, we focused on the molecular processes in the early stages of developing haustoria; that is, before the parasite engages in a physiological contact with its host. We describe first the identification of differentially expressed genes in young haustoria whose development was induced by far-red light and tactile stimuli in the absence of a host plant by suppression subtractive hybridization. To improve sequence information and to aid in the identification of the obtained candidates, reference transcriptomes derived from two species of Cuscuta, C. gronovii and C. reflexa, were generated. Subsequent quantitative gene expression analysis with different tissues of C. reflexa revealed that among the genes that were up-regulated in young haustoria, two xyloglucan endotransglucosylase/hydrolase (XTH) genes were highly expressed almost exclusively at the onset of haustorium development. The same expression pattern was also found for the closest XTH homologues from C. gronovii. In situ assays for XTH-specific action suggested that xyloglucan endotransglucosylation was most pronounced in the cell walls of the swelling area of the haustorium facing the host plant, but was also detectable in later stages of haustoriogenesis. We propose that xyloglucan remodelling by Cuscuta XTHs prepares the parasite for host infection and possibly aids the invasive growth of the haustorium.
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Dramsveien 201, 9037 Tromsø, Norway.
authors.forename: Stian
authors.initials: S
authors.lastname: Olsen
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Dramsveien 201, 9037 Tromsø, Norway * Present address: ArcticZymes AS, Sykehusveien 23, 9019 Tromsø, Norway.
authors.forename: Bernd
authors.initials: B
authors.lastname: Striberny
authors.affiliation: Institute of Botany, Christian-Albrechts-University of Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
authors.forename: Julien
authors.initials: J
authors.lastname: Hollmann
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Dramsveien 201, 9037 Tromsø, Norway Present address: Institute of Bio- and Geosciences (IBG-2: Plant Sciences), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, D-52428 Jülich, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Schwacke
authors.affiliation: Botany and Plant Science and Ryan Institute for Environmental, Marine and Energy Research, National University of Ireland Galway, Galway, Ireland.
authors.forename: Zoë
authors.initials: Z
authors.lastname: Popper
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Dramsveien 201, 9037 Tromsø, Norway kirsten.krause@uit.no.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Krause
mesh_terms: D002473:Cell Wall / Q000235:genetics / Q000528:radiation effects; D034182:Cuscuta / Q000033:anatomy & histology* / Q000201:enzymology* / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017343:Genes, Plant; D016695:Glycosyltransferases / Q000378:metabolism*; D006790:Host-Parasite Interactions / Q000528:radiation effects; D008027:Light; D058977:Molecular Sequence Annotation; D031316:Pelargonium / Q000469:parasitology* / Q000528:radiation effects; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D017423:Sequence Analysis, RNA; D013045:Species Specificity; D059467:Transcriptome / Q000235:genetics / Q000528:radiation effects
chemical_list: D012333:RNA, Messenger; D016695:Glycosyltransferases; C473049:xyloglucan - xyloglucosyltransferase
keywords: Cell wall; Cuscuta; haustorial gene expression; haustorium development; parasitic plant; xyloglucan endotransglucosylase/hydrolase (XTH).