BLUEBERRY FRUIT VOLATILES AS A POTENTIAL MARKER FOR RESISTANCE TO ANTHRACNOSE FRUIT ROT

Authors: Polashock, James; Saftner, Robert

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2007
Publication Date: 11/1/2007
Citation: Polashock, J.J., Saftner, R.A. 2007. Blueberry fruit volatiles as a potential marker for resistance to anthracnose fruit rot. Journal of the American Society for Horticultural Science. 132:859-868.

Interpretive Summary: Fresh fruit often rot during marketing causing considerable economic losses. Synthetic chemicals that can be applied to fruit to inhibit rot are undesirable due to potentially harmful effects on human health. Many natural fruit vapors that contribute to the unique aroma and taste of fruit also help to inhibit various diseases that cause fruit rot. We surveyed several blueberry varieties with known differences in fruit rot incidence for natural products that might contribute to inhibition of fruit rot. While the blueberry varieties tested were shown to produce differing amounts of a wide range of aromatic vapors, none of the differences were directly associated with inhibition of fruit rot. Other natural products produced by blueberry fruit that were not analyzed in this study may be important in inhibition of fruit rot. This information will be useful to researchers studying the impact of natural products on diseases that cause fruit rot.

Technical Abstract: Blueberry fruit produce antimicrobial volatiles including trans-2-hexenal that may confer resistance to anthracnose fruit rot, an important postharvest disease caused by Colletotrichum acutatum. To test the hypothesis that aromatic volatiles in blueberry fruit may be associated with postharvest fruit rot resistance, we compared volatiles emitted from intact fruit and fruit extracts of C. acutatum-inoculated and non-inoculated blueberry fruit stored 0 to 6 days from cultivars having a wide range of resistance to anthracnose. Antimicrobial volatiles detected included the aldehydes, trans-2-hexenal and hexanal; the monoterpenes, limonene, linalool, 8-hydroxylinalool, ''terpineol, and terpinyl acetate; and the sesquiterpenes, cadinene, caryophyllene and '-farnesene. Volatile emissions from intact fruit and extracts varied amongst the cultivars, with the early ripening cultivars generally showing higher volatile emissions than later ripening cultivars. While trans-2-hexenal, hexanal in extracts, terpinyl acetate, and cadinene emission increased in most cultivars during storage, quantitative changes were not correlated to exposure to anthracnose infection prior to storage. The results suggest that antimicrobial aldehydes and terpenes emitted from fully-ripe blueberry fruit and extracts are not inducible by C. acutatum infection and do not contribute to disease resistance against anthracnose fruit rot.