title: Volatile profiles of members of the USDA Geneva Malus Core Collection: utility in evaluation of a hypothesized biosynthetic pathway for esters derived from 2-methylbutanoate and 2-methylbutan-1-ol.
abstract: The volatile ester and alcohol profiles of ripening apple fruit from 184 germplasm lines in the USDA Malus Germplasm Repository at the New York Agricultural Experiment Station in Geneva, NY, USA, were evaluated. Cluster analysis suggested biochemical relationships exist between several ester classes. A strong linkage was revealed between 2-methylbutanoate, propanoate, and butanoate esters, suggesting the influence of the recently proposed "citramalic acid pathway" in apple fruit. Those lines with a high content of esters formed from 2-methylbutan-1-ol and 2-methylbutanoate (2MB) relative to straight-chain (SC) esters (high 2MB/SC ratio) exhibited a marked increase in isoleucine and citramalic acid during ripening, but those lines with a low content did not. Thus, the data were consistent with the existence of the hypothesized citramalic acid pathway and suggest that the Geneva Malus Germplasm Repository, appropriately used, could be helpful in expanding our understanding of mechanisms for fruit volatile synthesis and other aspects of secondary metabolism.
authors: Department of Horticulture, Michigan State University , East Lansing, Michigan 48824, United States.
authors: Nobuko
authors: N
authors: Sugimoto
authors: Philip
authors: P
authors: Forsline
authors: Randolph
authors: R
authors: Beaudry
mesh_terms: D053898:Biosynthetic Pathways; D004952:Esters / Q000737:chemistry* / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000145:classification / Q000254:growth & development / Q000378:metabolism; D027845:Malus / Q000737:chemistry* / Q000145:classification / Q000254:growth & development / Q000378:metabolism; D014481:United States; D016885:United States Department of Agriculture; D055549:Volatile Organic Compounds / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004952:Esters; D055549:Volatile Organic Compounds
keywords: aroma; citramalate; ester; flavor; isoleucine; threonine