Genetic transformation of grape varieties and rootstocks via organogenesis

A protocol was standardized to regenerate six grape 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 %), and was less successful with Vitis rupestris ‘St. George’ (85.4 %) and ‘101-14 Millardet et de Grasset ( Vitis riparia × V. rupestris )’ (79.6 %). Benzylaminopurine and naphthaleneacetic acid was the most effective combination of cytokinin and auxin for MB formation. 100 µg/ml kanamycin was a better antibiotic selection agent than 2.0 µg/ml hygromycin during transformation. The expression of green fluorescent protein was evaluated with in vitro leaves and roots. Transformation efficiency using meristematic slices was a function of the 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 %). This study found that MB induction was a fast and simple alternative for genetic transformation of grape cultivars.