Biosynthesis of trans-2-Hexenal in Response to Wounding in Strawberry Fruit

Abstract

Wounded strawberry fruit produces a diverse group of volatile compounds including aldehydes, alcohols, and esters derived from the lipoxygenase (LOX) and hydroperoxide lyase (HPL) pathways. Because the wound volatiles may play an important role in plant-fungal interaction, the goal of this study was to develop a greater understanding about the biosynthesis of the major wound volatile, trans-2-hexenal (t-2-H), produced by strawberry fruit upon wounding. To that end, composition and quantity of total and free fatty acids of control and wounded strawberry fruit were analyzed. In addition, activities of the key enzymes, LOX and HPL, and production of C6 aldehydes were determined. Intact strawberry fruit did not produce detectable t-2-H which is derived from alpha-linolenic acid (18:3). However, in response to wounding by bruising, strawberry fruit emitted t-2-H and its precursor cis-3-hexenal (c-3-H). The level of total lipid 18:3 in the fruit increased 2-fold in response to wounding, whereas free 18:3 declined slightly ( approximately 30%). At 10 min following wounding, fruit exhibited a 25% increase in LOX activity, which leads to the production of 13-hydroperoxyoctadecatrienoic acid (13-HPOT) from 18:3. The activity of HPL, which catalyzes formation of cis-3-hexenal from 13-HPOT, increased 2-fold by 10 min after wounding. Thus, during a 15 min period after wounding, free 18:3 substrate availability and the activity of two key enzymes, LOX and HPL, changed in a manner consistent with increased c-3-H and t-2-H biosynthesis.

Shelf stable intermediate moisture pineapple (Ananas comosus) slices using hurdle technology

“…The cutting process resulted in tissue disruption and membrane breakdown leading to the release of hydrolytic enzymes. Enzymatic degradation of cellulose, hemicellulose and pectin led to texture losses during storage (Myung, Hamilton-Kemp, & Archbold, 2006). This effect, being pronounced in freshly cut samples in the present study, was not reduced by the potassium metabisulfite dip or its combination with osmotic dehydration.…”

Identification of (Z)-3:(E)-2-Hexenal Isomerases Essential to the Production of the Leaf Aldehyde in Plants

“…S6A). This expression might contribute to producing (E)-2-hexenal as an antifungus volatile as in strawberry (37). In potato, higher expression of StHI1 and StHI2 was observed in sprouts (supplemental Fig.…”

A comprehensive review on Sauvignon blanc aroma with a focus on certain positive volatile thiols

“…Studies have shown a rapid increase in the lipoxygenase VvLOXC and -O transcripts in B. cinerea infected berries. These enzymes are responsible for the release of (E)-2-hexenal (HamiltonKemp, Archbold, Collins, & Yu, 2003;Hatanaka, 1993;Myung, Hamilton-Kemp, & Archbold, 2006) and other reactive aldehydes such as hexanal and nonenal (Mueller, 2004). These compounds are toxic to the pathogen and can become toxic to the plant itself at a critical level (Hamilton-Kemp et al, 2003;Hatanaka, 1993;Myung et al, 2006).…”