Skip to main content
ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #344501
Title: Two dominant loci determine resistance to Phomopsis cane lesions in F1 families of hybrid grapevines

Author
item BARBA, PAOLA - La Platina Resesearch Center
item Lillis, Jacquelyn
item LUCE, STEVE - Cornell University
item TRAVADON, RENAUD - University Of California
item OSIER, MICHAEL - Rochester Institute Of Technology
item Baumgartner, Kendra
item WILCOX, WAYNE - Cornell University
item REISCH, BRUCE - Cornell University
item Cadle-Davidson, Lance

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2018
Publication Date: 4/17/2018
Citation: Barba, P., Lillis, J.A., Luce, S., Travadon, R., Osier, M., Baumgartner, K., Wilcox, W.F., Reisch, B.I., Cadle Davidson, L.E. 2018. Two dominant loci determine resistance to Phomopsis cane lesions in F1 families of hybrid grapevines. Theoretical and Applied Genetics. 131(5):1173-1189. https://doi.com/10.1007/s00122-018-3070-1.
DOI: https://doi.org/10.1007/s00122-018-3070-1

Interpretive Summary: Phomopsis cane and leaf spot, caused by the fungus Diaporthe ampelina (syn = Phomopsis viticola), attacks grapevine stems and berries, causing rotten lesions that kill these tissues. Resistance of the grapevines attacked by this disease were studied among the progeny resulting from crosses of the following parent vines: ‘Horizon’, Illinois 547-1, Vitis cinerea B9 and V. vinifera ‘Chardonnay’. All such families had progeny that were extremely susceptible, developing lesions on both dormant canes and maturing fruit clusters. Among progeny from all families, the same proportion of progeny were susceptible (25% of all progeny), based on what we saw in terms of their symptoms on dormant canes and maturing fruit, under natural levels of disease in the field. In the greenhouse, we confirmed the same plants that were suscpetible in the field (from a subset of resistant and susceptible ‘Chardonnay’ x V. cinerea B9 progeny) were also suscpetible to green shoot infections. High-density genetic maps were used to localize novel qualitative resistance loci named Rda1 and Rda2 from V. cinerea B9 and ‘Horizon’, respectively. Co-linearity between genetic and physical maps allowed localization of Rda2 locus between 1.5 and 2.4 Mbp on chromosome 7 of the V. vinifera 12X.0 PM40024 genome. The physical location of Rda1 was narrowed to 19.3 and 19.6 Mbp of chromosome 15, which spans a cluster of five NB-LRR genes. Further dissection of this locus was obtained by QTL mapping of gene expression values 14 hours after artificial inoculation across a subset of the ‘Chardonnay’ x V. cinerea B9 progeny. This provided evidence for the association between transcript levels of two of these NB-LRR genes with Rda1, with increased NB-LRR expression among susceptible progeny. In resistant parent V. cinerea B9, inoculation with D. ampelina was characterized by upregulation of SA-associated genes and down-regulation of ethylene pathways, suggesting an R-gene mediated response. With dominant effects associated with disease-free berries and minimal symptoms on canes, Rda1 and Rda2 are promising loci for grapevine genetic improvement.

Technical Abstract: Phomopsis cane and leaf spot, caused by the hemibiotrophic fungus Diaporthe ampelina (syn = Phomopsis viticola), produces lesions on grapevine stems and berries, reducing productivity. Host resistance was studied on three F1 families derived from crosses involving ‘Horizon’, Illinois 547-1, Vitis cinerea B9 and V. vinifera ‘Chardonnay’. All families had progeny with extremely susceptible phenotypes, developing lesions on both dormant canes and maturing fruit clusters. On progeny from all three families, segregation of symptoms was observed under natural levels of inoculum in the field. Phenotypes on green shoots were confirmed on a subset of resistant and susceptible ‘Chardonnay’ x V. cinerea B9 progeny under controlled inoculations in greenhouse. High-density genetic maps were used to localize novel qualitative resistance loci named Rda1 and Rda2 from V. cinerea B9 and ‘Horizon’, respectively. Co-linearity between genetic and physical maps allowed localization of Rda2 locus between 1.5 and 2.4 Mbp on chromosome 7 of the V. vinifera 12X.0 PM40024 genome. The physical location of Rda1 was narrowed to 19.3 and 19.6 Mbp of chromosome 15, which spans a cluster of five NB-LRR genes. Further dissection of this locus was obtained by QTL mapping of gene expression values 14 hours after artificial inoculation across a subset of the ‘Chardonnay’ x V. cinerea B9 progeny. This provided evidence for the association between transcript levels of two of these NB-LRR genes with Rda1, with increased NB-LRR expression among susceptible progeny. In resistant parent V. cinerea B9, inoculation with D. ampelina was characterized by upregulation of SA-associated genes and down-regulation of ethylene pathways, suggesting an R-gene mediated response. With dominant effects associated with disease-free berries and minimal symptoms on canes, Rda1 and Rda2 are promising loci for grapevine genetic improvement.