Research


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Research project (§ 26 & § 27)
Duration : 2016-07-01 - 2017-09-30

The project “Berry Shrivel – an unsolved physiological disorder in grapevine” analyses the early changes during BS induction. The ripening disorder is of highly economic importance for winegrowers and especially in Austria the main red wine cultivar Zweigelt can show high incidence of BS in vineyards. The onset of BS induction starts at or short after Veraison, the start of grape berry ripening, and is leading to grapes of low quality with low sugar contents, high acidity, reduced anthocyanin content and strong off flavors. The processes and causes leading to BS induction and symptom development are still unclear. In the presented project we are following the hypothesis that BS is due to a reduced transport of assimilates towards grape berries. According to the current knowledge we are focusing on anatomical changes within the vascular system and we will establish an in vitro system to manipulate the carbohydrate support of single berries with the aim to artificially induce BS. Thereby different microscopic and molecular biological methods will be applied. Our approach is the first effort to analyze these early events during BS induction and will provide essential knowledge towards the unraveling of this complex ripening disorder affecting grape berries.
Research project (§ 26 & § 27)
Duration : 2016-05-01 - 2018-07-31

Abstract Since grape phylloxera (Daktulosphaira vitifoliae; Phylloxeridae) has been introduced into Europe in the second half of the 19th cenutry, it became the most threatening pest for worldwide viticulture. The root form of the monophagous insect initiates the development of root galls (nodosities) on susceptible or partial resistant Vitis spp. It harms the host plant by consuming assimilates, interrupting water and mineral uptake, manipulation of the sink source allocation and creating entrances for secondary infections. Grafting scions onto resistant rootstocks of American Vitis spp. and their hybrids were the main cultural management technique to fight this parasite for more than 150 years. Because of the development of aggressive phylloxera strains establishing larger populations in European vineyards and the effects of biotic and abiotic stresses (in the cause of global warming) multiplied through phylloxerated root tips, phylloxera-based damages in vineyards are increasing. The knowledge on the phylloxera-grapevine interaction is still scarce and covers the plant-based responses only since no resistant rootstocks are available to date. All rootstock are partially resistant and specific effectors, secreted by the parasite, are required to establish a compatible Phylloxera-Vitis interaction. Knowledge about these effectors allows the identification of plant defense pathways required for the induction of solid resistance against phylloxera in grapevine. This study aims to identify and define effector molecules of phylloxera-Vitis interactions, which affect the aggressivity of the parasites. Additionally basic knowledge on gall induction and formation as well as influences of effectors on signaling pathways will be gained on a molecular and cellular basis. Within the project we plan to identify up regulated transcripts in the insects by RNA extraction combined with novel RNAseq technology. Up regulation of transcripts are confirmed using qRT-PCR techniques. Additionally we want to identify and characterize proteins extracted from phylloxera individuals of two strains with differing aggressivity AT1 and DE1 as well as parasitic proteins localized in the host feeding tissues of three Vitis plants (Rootstock Teleki (V. berlandieri x V. riparia) 5C, Rootstock Fercal (B.C. n°1B × Richter 31) and Vitis vinifera L. cv. Riesling), using GE- LC-MS/MS and LC-MS/MS techniques. Using bioinformatic approaches candidate effectors are selected out of proteomic and transcriptomic results. Regulatory influences of the candidate effectors are confirmed by testing the host plant response of Vitis cell cultures. Expression levels of effector-treated and non-treated cells are compared using qRT-PCR technique.
Research project (§ 26 & § 27)
Duration : 2015-02-01 - 2018-12-31

The overall goal of the proposed project is to develop a concept for the management of Central European vineyards and their surrounding landscapes in order to enhance biodiversity providing those ecosystem services which have the potential to improve vineyard health and economic value. We will use a standardized set of observational and experimental studies across a wide range of Central-European (non-Mediterranean) vineyard systems in France, Switzerland, Germany, Austria and Romania in order to unravel relationships between factors promoting biodiversity focusing especially on soil biodiversity (plants, biological activity and mesofauna) and functioning and the relevant supporting, provisioning and regulating ecosystem services required such as soil fertility, structural stability, water provision as well as pest and weed control. Three scales will be considered, a) the vineyard production area with its zones not directly used for cultivation such as alleyways, b) the vineyard surrounding area with its ecological infrastructures, and c) the surrounding landscape with its landscape elements. The observational studies will be carried out at a considerable number of vineyard locations in each participating country including a set of plots covering landscape diversity, sampling of soil properties, soil biological activity, plants and mesofauna as well as management factors such as tillage, herbicide weeding, mowing and slashing and fertilization on the plot scale. Additionally, type, density and patterns of ecological infrastructures such as hedges, ditches and other semi-natural habitats within and around the vineyard systems as well as relevant landscape parameters representing landscape complexity and connectivity will be considered.

Supervised Theses and Dissertations