Cecilia Aguero,* Xiaoqing Xie, Yuejin Wang, and M. Andrew Walker
*Department of Viticulture and Enology, University of California, Davis, CA 95616 (cbaguero@ucdavis.edu)

A protocol was standardized to regenerate six grapevine cultivars through meristematic bulk (MB) induction, which was used for genetic transformation. Meristematic bulk induction worked best with Vitis vinifera Thompson Seedless (98.4%), followed by Chardonnay (97.6%), Redglobe (90.2%), and Cabernet Sauvignon (86.2%). It was less successful with V. rupestris St. George (85.4%) and V. riparia x V. rupestris 101-14 Millardet et de Grasset (79.6%). Benzylaminopurine (BA) and naphthaleneacetic acid (NAA) was the most effective combination of cytokinin and auxin for MB formation. Kanamycin was a better antibiotic selection agent than hygromycin during transformation. The expression of green fluorescent protein (GFP) was evaluated with in vitro leaves and roots. Transformation efficiency using meristematic slices was a function of genotype. Transformation efficiency was greatest in Chardonnay (51.7%), followed by Thompson Seedless (42.3%), St. George (41.6%), Redglobe (40%), Cabernet Sauvignon (35.6%), and 101-14 Mgt (29.9%). Overall, MB induction was a faster and simpler alternative for genetic transformation of grapevine cultivars.

Funding Support: California Grape Rootstock Improvement Commission, the California Grape Rootstock Research Foundation, the American Vineyard Foundation, the CDFA Improvement Advisory Board, and the California Table Grape Commission. Xiaoqing Xie was supported by the College of Horticulture, Northwest A & F University, Yangling, Shaanxi, China