MAP-BASED IDENTIFICATION AND POSITIONAL CLONING OF XYLELLA FASTIDIOSA RESISTANCE GENES FROM KNOWN SOURCES OF PIERCES DISEASE RESISTANCE IN GRAPE

• Author(s): Riaz, Summaira; Walker, Andrew;
• Abstract: Development of a framework SSR genetic linkage map based on the 9621 family (D8909-15 (V. rupestris x V. arizonica) x (V. rupestris x V. arizonica/candicans)) is complete. The mapping population segregates for Pierces disease (PD) resistance and was expanded from 116 to 188 genotypes. The current genetic linkage map consists of 236 non-AFLP markers (SSR, EST-SSR and ESTP-RFLP) in 19 linkage groups. The PD resistance locus, PdR1, maps to linkage group 14 of the male parent (F8909-17), which now consists of 30 markers, 9 of which are localized within 10 cM of PdR1. To avoid confounding affects from resistance inherited from D8909-15 a new population has been chosen and is being prepared for mapping. This population (04190) is a cross of V. vinifera F2-7 x F8909-08 (sibling of F8909-17). We have confirmed a heterozygous Xylella fastidiosa (Xf) resistance inheritance (the same as F8909-17) on a subset and produced 4,500 seeds in this population for use in our mapping and positional cloning efforts. A set of 220 plants were selected for DNA extraction (to add PD group markers) and cuttings were collected from 160 plants for screening for Xf resistance; resistance segregates 1:1 in this population. In order to understand the stability and segregation of resistance to PD from different sources, 6 different mapping populations are under study. We are also continuing mapping efforts in the 0023 population a cross of D8909-15 x V. vinifera B90-116, so that we can compare these resistance sources. Extensive data for cluster and berry traits, and Xf resistance exists for about 200 plants in the 0023 population. A preliminary map, locates QTLs on a number of the linkage groups.
• Publication Date: Dec 2005
• Journal: 2005 Pierce's Disease Research Symposium