ABSTRACT. A cDNA library of Chinese wild Vitis amurensis, which is the most cold-resistant species in the genus Vitis, was constructed using young leaves of seedlings of the clone Heilongjiang potted and subjected to cold stress. The leaves were harvested at various times after cold stress for total RNA extraction, which was used to generate expressed sequence tags (ESTs). The titer of the original library was 2.67 x 10 6 pfu/mL and the corresponding combination frequency was 98.5%. The test values of the amplified library were 1.53 x 10 9 pfu/ mL and 98.2%, respectively. After randomly choosing, cloning and sequencing, 227 ESTs with high quality were obtained and submitted to GenBank database. Using BLASTX, 79.7% of the ESTs shared homology with known functional DNA sequences and 20.3% shared significant homology with unknown proteins. Some potential hardinessrelated ESTs were obtained, which were involved in signal transduction, Analysis of cold-responsive genes from Vitis amurensis stress inducement, defense reactions, transcription factors, etc. Some functional genes identified from the cDNA library have potential for plant defense. These sequences will be subjected to further researches on hardiness genes and their molecular mechanisms.
ABSTRACT. The resistance of wild Vitis germplasm, including Chinese and American wild Vitis and Vitis vinifera cultivars, to powdery mildew (Uncinula necator Burr.) was evaluated for two consecutive years under natural conditions. Most of the Chinese and North American species displayed a resistant phenotype, whereas all of the European species were highly susceptible. The Alachua and Conquistador accessions of Vitis rotundifolia species, which originated in North America, were immune to the disease, while Baihe-35-1, one of the accessions of Vitis pseudoreticulata, showed the strongest resistance among all Chinese accessions evaluated. Three rapid amplified polymorphic DNA (RAPD) markers, OPW02-1756, OPO11-964, and OPY13-661, were obtained after screening 520 random primers among various germplasm, and these markers were found to be associated with powdery mildew resistance in Baihe-35-1 and in some Chinese species, but not in any European species. Analysis of F 1 and F 2 progenies of a cross between resistant Baihe-35-1 and susceptible Carignane (V. vinifera) revealed that the three RAPD markers were linked to the powdery resistant trait in Baihe-35-1 plants. Potential applications of the identified RAPD markers for gene mapping, marker-assisted selection, and breeding were investigated in 168 F 2 progenies of the same cross. Characterization of the resistant phenotype of the selected F 2 seedlings for breeding a new diseaseresistant grape cultivar is in progress.
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