Institut für Rebenzüchtung
In contrast to the almost hairless cultivated vine (V. vinifera), certain Vitis species have very densely hairy leaf undersides, which leads to biotic (downy mildew) and abiotic resistance (drought). This gene pool needs to be exploited through breeding for sustainable, resource-conserving and climate-adapted viticulture to permanently reduce the application of copper and synthetic fungicides. The proposed project follows two complementary strategies.(1) Deciphering the genetics of the leaf hairiness trait. In the genome of the very hairy wild species V. labrusca, regions responsible for the formation of leaf hairs will be identified by QTL mapping. By genome sequencing of a V. labrusca genotype, gene expression studies and sequence comparisons with V. vinifera, trait-relevant positional candidate genes will be determined. Candidate genes from the LH1 locus of V. vinifera, for the absence of leaf hairs, were identified in advance. A comparative amplicon sequencing approach will reveal differences between Vitis genotypes with different levels of leaf hairs and plants without leaf hairs. The sequence data will be used to generate specific mobile gene editing constructs.(2) Development of a transgene-free gene editing method for gene function studies and rapid and precise adaptation of leaf hair density and, in the long term, other traits in existing grape varieties. A non-transgenic scion is grafted onto a transgenic rootstock expressing a mobile gene editing system. After the gene editing system is transported across the grafting site, the scion is edited in a gene-specific manner, but remains transgene-free. In parallel approaches, tobacco (heterologous) or grapevine (homologous) serve as a rootstock for Vitis shoots to be edited.
Federal Ministry of Education and Research
