Research Accomplishment Reports 2007

Regulation of Expression and Activity of Sorbitol Dehydrogenase in Apple

D. Archbold
Department of Horticulture

 

Project Description

Crop load adjustment during the first 6 weeks of apple fruit development is an essential cultural practice to optimize fruit size and quality, yet it is unclear why some fruit persist and others drop naturally or in response to thinning techniques. Chemical thinning agents are commonly used, but their mode of action is unknown. A greater understanding of both natural fruit drop and that in response to chemical thinning could lead to development of new thinning agents, as the current list of acceptable compounds is very short and includes none useful in organic apple production systems. Fruit tissues and shoots subtending the fruit were sampled during the weeks leading up bloom as well as the weeks after bloom for analyses of carbohydrate levels and for enzymes critical to carbohydrate metabolism.

Impact

Considering both SDH activity and carbohydrate availability, natural fruit drop and may be due to declining availability of carbohydrates and not to an inability to utilize them. By identifying compounds that can reduce photosynthesis, slow carbohydrate translocation, or otherwise temporarily limit carbohydrate availability to young fruit, new options for apple crop load adjustment may be developed.

Publications

Nosarzewski, M. and D.D. Archbold. 2007. Tissue-specific expression of sorbitol dehydrogenase in apple fruit during early development. J. Exp. Bot. 58:1863-1872.

Myung, K., T.R. Hamilton-Kemp, and D.D. Archbold. 2007. Interaction with and effects on the profile of proteins of Botrytis cinerea by C6 aldehydes. J. Agr. Food Chem. 55:2182-2188.