Poster: Secondary metabolism

Abs # 259: Biosynthesis of trans-2-hexenal in strawberry fruit in response to wounding

Presenter:	Myung, Kyung , kmyun2@uky.edu
Authors	Myung, Kyung  (A)   Hamilton-Kemp, Thomas R (A)   Hildebrand, David F (B)   Archbold, Douglas D (A)
Affiliations:	(A): Department of Horticulture, University of Kentucky (B): Department of Agronomy, University of Kentucky

Intact strawberry fruit did not produce detectable trans-2-hexenal which is derived from α-linolenic acid (18:3). However, in response to wounding by gentle bruising, strawberry fruit emitted trans-2-hexenal with the largest quantity produced within 15 minute following injury. The level of total lipid 18:3 in the fruit increased two fold in response to wounding whereas free 18:3 declined slightly (about 30%). At 10 minute following wounding, fruit was found to have a 25% increase in 13-lipoxygenase (LOX) activity, which leads to the production of 13-hydroperoxyoctadecatrienoic acid (13-HPOT) from 18:3. The activity of hydroperoxide lyase (HPL), which catalyzes formation of cis-3-hexenal, the precursor of trans-2-hexenal, from 13-HPOT, increased two fold at 10 minute after wounding. Thus, within 15 minute after wounding, free 18:3 substrate availability and the activity of the key enzymes, LOX and HPL, change in a manner consistent with increased trans-2-hexenal biosynthesis.