2017 ASHS Annual Conference

M. sieversii is distinguished from other wild Malus species as being an excellent source of economically important traits, including stress and disease resistance. USDA-sponsored expeditions to Central Asia have resulted in a large collection of M. sieversii accessions that are maintained at the USDA Plant Genetics Resources Unit (PGRU) in Geneva, NY. M. sieversii - PI 613981, is one of the elite lines that was originally selected for collection in Kazakhstan for drought tolerance and potential disease resistance. The t identification of the genes responsible for these and other traits, however, have not been explored. Therefore, it is important to identify stress-tolerance genes in wild and distantly-related genotypes of apple to discover how they differ from the genes identified in commercial cultivars and to identify any potential “new” genes associated with stress tolerance. Thus far, large-scale, high-throughput screening for stress tolerance genes in apple has not been conducted. In the present project, the FOX (Full-length cDNA Over-eXpressing) gene hunting system, which represents an alternative gain-of-function gene hunting technique, has been used to generate gain-of-function mutant lines in Arabidopsis carrying up to 10,000 independent apple cDNAs derived from a cDNA library of M. sieversii – PI613981 constructed from mid-winter bark tissues. The high-throughput screening effort will focus on identifying genes related to freezing tolerance, salt tolerance, drought tolerance, and morphological traits (dwarfing, early-flowering, branching, etc.). Initial characterization of the system, a sampling of inserted apple genes, and examples of morphological mutants will be presented.