title: Expression of putative expansin genes in phylloxera (Daktulosphaira vitifoliaeFitch) induced root galls ofVitisspp.
abstract: Grape phylloxera (Daktulosphaira vitifoliaeFitch) is a serious global pest in viticulture. The insects are sedentary feeders and require a gall to feed and reproduce. The insects induce their feeding site within the meristematic zone of the root tip, where they stay attached, feeding both intra- and intercellularly, and causing damage by reducing plant vigour. Several changes in cell structure and composition, including increased cell division and tissue swelling close to the feeding site, cause an organoid gall called a nodosity to develop. Because alpha expansin genes are involved in cell enlargement and cell wall loosening in many plant tissues it may be anticipated that they are also involved in nodosity formation. To identify expansin genes inVitis viniferacv.Pinot noir, we mined for orthologues genes in a comparative analysis. Eleven putative expansin genes were identified and shown to be present in the rootstock Teleki 5C (V. berlandieriPlanch. xV. ripariaMichx.) using specific PCR followed by DNA sequencing. Expression analysis of young and mature nodosities and uninfested root tips were conducted via quantitative real time PCR (qRT-PCR). Up-regulation was measured for three putative expansin genes (VvEXPA15, -A17 and partly -A20) or down-regulation for three other putative genes (VvEXPA7, -A12, -A20) in nodosities. The present study clearly shows the involvement of putative expansin genes in the phylloxera-root interaction.
authors.affiliation: Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Konrad-Lorenz Str. 24, 3430 Tulln, Austria ; Syngenta Crop Protection Research Stein, Schaffhauserstrasse 101, 4332 Stein, Switzerland.
authors.forename: N C
authors.initials: NC
authors.lastname: Lawo
authors.affiliation: Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Konrad-Lorenz Str. 24, 3430 Tulln, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Griesser
authors.affiliation: Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Konrad-Lorenz Str. 24, 3430 Tulln, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Forneck
keywords: V. vinifera; Vitis berlandieri × V. riparia; gall; nodosity; phylloxera; qRT-PCR; root