| Autor: |
Bettinelli P; Center Agriculture Food Environment (C3A), University of Trento, 38098 San Michele all'Adige, TN, Italy.; Grapevine Genetics and Breeding Unit, Research and Innovation Centre, Fondazione Edmund Mach, 38098 San Michele all'Adige, TN, Italy., Nicolini D; Grapevine Genetics and Breeding Unit, Research and Innovation Centre, Fondazione Edmund Mach, 38098 San Michele all'Adige, TN, Italy., Costantini L; Grapevine Genetics and Breeding Unit, Research and Innovation Centre, Fondazione Edmund Mach, 38098 San Michele all'Adige, TN, Italy., Stefanini M; Grapevine Genetics and Breeding Unit, Research and Innovation Centre, Fondazione Edmund Mach, 38098 San Michele all'Adige, TN, Italy., Hausmann L; JKI Institute for Grapevine Breeding, Geilweilerhof, 76833 Siebeldingen, Germany., Vezzulli S; Grapevine Genetics and Breeding Unit, Research and Innovation Centre, Fondazione Edmund Mach, 38098 San Michele all'Adige, TN, Italy. |
| Abstrakt: |
Black rot (BR), caused by Guignardia bidwellii , is an emergent fungal disease threatening viticulture and affecting several mildew-tolerant varieties. However, its genetic bases are not fully dissected yet. For this purpose, a segregating population derived from the cross 'Merzling' (hybrid, resistant) × 'Teroldego' ( V. vinifera , susceptible) was evaluated for BR resistance at the shoot and bunch level. The progeny was genotyped with the GrapeReSeq Illumina 20K SNPchip, and 7175 SNPs were combined with 194 SSRs to generate a high-density linkage map of 1677 cM. The QTL analysis based on shoot trials confirmed the previously identified Resistance to Guignardia bidwellii ( Rgb )1 locus on chromosome 14, which explained up to 29.2% of the phenotypic variance, reducing the genomic interval from 2.4 to 0.7 Mb. Upstream of Rgb 1, this study revealed a new QTL explaining up to 79.9% of the variance for bunch resistance, designated Rgb 3. The physical region encompassing the two QTLs does not underlie annotated resistance ( R )-genes. The Rgb 1 locus resulted enriched in genes belonging to phloem dynamics and mitochondrial proton transfer, while Rgb 3 presented a cluster of pathogenesis-related Germin-like protein genes, promoters of the programmed cell death. These outcomes suggest a strong involvement of mitochondrial oxidative burst and phloem occlusion in BR resistance mechanisms and provide new molecular tools for grapevine marker-assisted breeding. |
