Journal Article

A 13-lipoxygenase, TomloxC, is essential for synthesis of C5 flavour volatiles in tomato

Jiyuan Shen, Denise Tieman, Jeffrey B. Jones, Mark G. Taylor, Eric Schmelz, Alisa Huffaker, Dawn Bies, Kunsong Chen and Harry J. Klee

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 65, issue 2, pages 419-428
Published in print February 2014 | ISSN: 0022-0957
Published online January 2014 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jxb/ert382

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C5 volatile compounds, derived from fatty acids, are among the most important contributors to consumer liking of fresh tomatoes. Despite their important roles in flavour, the genes responsible for C5 volatile synthesis have yet to be identified. This work shows that their synthesis is catalysed in part by a 13-lipoxygenase (LOX), TomloxC, the same enzyme responsible for synthesis of C6 volatiles. C5 synthesis is independent of hydroperoxide lyase (HPL); moreover, HPL knockdown significantly increased C5 volatile synthesis. This LOX-dependent, HPL-independent pathway functions in both fruits and leaves. Synthesis of C5 volatiles increases in leaves following mechanical wounding but does not increase in response to infection with Xanthomonas campestris pv. vesicatoria. Large reductions in C5 and C6 volatiles in antisense TomloxC knockdown plants were observed but those reductions did not alter the development of disease symptoms, indicating that these volatiles do not have an important defensive function against this bacterial pathogen.

Keywords: C5 volatiles; hydroperoxide lyase; jasmonic acid; 13-lipoxygenase; tomato; wounding; Xanthomonas campestris pv. vesicatoria.

Journal Article.  6157 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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