2011 Annual Report
1a.Objectives (from AD-416)
1. Determine some of the key genetic factors controlling environmental adaptation and fruit quality differences among cultivated grapes and between cultivated and wild grapes.
1A. Identify molecular markers tightly linked to QTL controlling phenotypic variation in grape for environmental adaptation and fruit quality.
1B. Identify candidate genes for environmental adaptation through characterization of differences in gene content and global gene expression among wild grapes with divergent phenotypes.
2. Develop grape germplasm with novel phenotypes for fruit quality traits.
1b.Approach (from AD-416)
The objectives will be accomplished by applying genetic and genomic tools and research strategies, including populations and marker development, dissection of complex phenotypes, QTL mapping, gene expression analysis, and mutagenesis. Genetic linkage maps will be contructed from populations segregating for economically important traits. Genetic dissection of traits will be conducted in populations derived from bi-parental crosses as well as diverse cultivated and wild grape germplasm.
Polyphenols are an important group of secondary metabolites with significant nutrition and health benefits to humans. We evaluated the profiles of 36 polyphenolic compounds in the ripe berry samples of 344 European grape (Vitis vinifera) cultivars for two successive years (2008 and 2009 seasons). These cultivars represent a core collection of worldwide Vitis germplasm maintained at the USDA-ARS Vitis Clonal Repository in Davis of California, USA. The 36 polyphenolic compounds, including 16 anthocyanins, 6 flavonols and 6 flavanols, 6 hydroxycinnamic acids, and 2 hydroxybenzoic acids, were identified via liquid chromatography. We had also characterized the polyphenolic composition and content in the ripe berries of 147 grape accessions representing 16 Vitis species maintained in the USDA-ARS Vitis Clonal Repository in Geneva, New York. A total of 48 polyphenolic compounds, including 28 anthocyanins, 6 flavonols, 6 flavanols , 6 hydroxycinnamic acids, and 2 hydroxybenzoic acids, were identified. The wild grape species had unique presence of abundant di-glucoside derivatives of anthocyanins which were predominantly nonacylated. The mean contents for anthocyanins, flavanols, flavonols , hydroxycinnamic acids, and hydroxybenzoic acids in the wild species were about 2 to 10 folds higher than their respective counterparts in the most widely cultivated grape species V. vinifera.
Somatic embryogenesis has been used in many species for generating somaclonal variation and introducing new trait variation through transformation for trait improvement. We have successfully established somatic embyogenesis, tissue culture and transformation capability for improving traits in grapevines. We have generated mutant plants derived from EMS-treated cell suspension cultures of Vitis vinifera cv. Chardonnay. These plants will be analyzed and screened for novel traits important for grapevine improvement.
Grapevines grown in many regions of the Eastern United States are poorly adapted to low-temperature and frequently are damaged by severe winters and fluctuating temperature during the spring and fall. There is tremendous variation among cultivated and wild grapes for tolerance to low-temperature stress, including some types that are substantially more tolerant to freezing than the primary cultivated species. In FY11 we completed a long-term project to map regions of the grape genome responsible for controlling differences in freezing tolerance.
Grape aroma is a primary determinant of table grape, unfermented juice, and wine quality. In collaboration with the University of British Columbia a project was continued to conduct an association genetics screen for grape aroma in a subset of the USDA grape germplasm collection. In FY11 the content of several aromatic compounds was determined from fruit samples collected in previous years from over 300 different grapevine varieties maintained by USDA.
All these activities are in support of National Program 301 components 3 (Genetic Improvement of Crops) and component 2 (Crop Informatics, Genomics, and Genetic Analyses) and are specified in the project’s objectives.
Localized the position of cold hardiness genes in the grape genome. Grapevines grown in many regions of the Eastern United States are poorly adapted to low-temperature and frequently are damaged by severe winters and fluctuating temperature during the spring and fall. There is tremendous variation among cultivated and wild grapes for tolerance to low-temperature stress, including some types that can survive -40 F. To understand the genetic control of freezing tolerance, the locations of genes controlling freezing-tolerance were identified by ARS researchers at Geneva, NY, in the grape genome based on the analysis of offspring of parents that differ dramatically in their cold hardiness. This experiment was conducted in a population of 190 individuals and utilized over 2000 molecular markers to help identify regions of the genome that are important for freezing tolerance. The mapping of this trait is the first step in developing an assay that will improve the selection efficiency within grape breeding programs for this trait and generating improved cultivars of grape for cold climates.
Myles, S., Boyko, A., Owens, C.L., Brown, P., Fabrizio, G., Aradhya, M.K., Prins, B.H., Reynolds, A., Chia, J., Ware, D., Bustamante, C., Buckler IV, E.S. 2011. Genetic structure and domestication history of the grape. Proceedings of the National Academy of Sciences. 10.1073/pnas.1009363108.
Liang, Z., Owens, C.L., Zhong, G., Cheng, L. 2011. Polyphenolic profiles detected in the ripe berries of Vitis vinifera germplasm. Journal of Food Biochemistry. 129:940-950.