Research Abstracts Online
January 2010 - March 2011
University of Minnesota Twin Cities
College of Food, Agricultural, and Natural Resource Sciences
of Horticultural Science
PI: Cindy B. Tong
Postharvest Fruit Physiology
Texture is an important factor in sensory liking of fruit. It also affects the storage life of fruit, its susceptibility to bruising and diseases, and its transportability. Changes in turgor pressure and degradation of the cell wall are major contributors to fruit softening. The overall goal of this project is to understand the molecular, biochemical, and physiological mechanisms involved in maintaining postharvest quality of fruit, using apples as the study system.
Expansins are proteins that play a role in cell wall extension in plants. They are present in mature fruit tissue, where their roles, however, are unknown. In tomato fruit, suppression of one Expansin gene, LeExp1, resulted in the production of tomato fruit that remained firm longer than unmutated fruit. Overexpression of this gene resulted in softer fruit. The expression of expansin genes MdEXPA1, MdEXPA2, MdEXPA3, MdEXPA4, MdEXPA5 and MdEXPA7 was studied among apple cultivars that remained crisp, or lost crispness, at harvest and after 8 weeks of cold storage. Two alleles of MdEXPA2 were identified and 41 apple genotypes were allelotyped for this gene.
Diana Trujillo, Graduate Student