The maize death acids, 10-oxo-11-phytoenoic acid and derivatives, are rapidly induced phytoalexins with multiple biological activities

Plant cellular damage promotes the interaction of lipoxygenases (LOX) with free fatty acids to yield 9- and 13-hydroperoxides which are further metabolized into diverse oxylipins. The enzymatic action of 13-LOX on linolenic acid enables production of 12-oxo-phytodienoic acid (12-OPDA) and its downstream products, jointly known as jasmonates. As signals, jasmonates have related yet distinct roles in the regulation of plant resistance against insect and pathogen attack. An additional and conceptually parallel pathway involving 9-LOX activity on linoleic acid leads to the production of 10-oxo-11-phytoenoic acid (10-OPEA). Despite structural similarity to jasmonates, physiological roles for 10-OPEA have remained unclear. Both 12-OPDA and 10-OPEA equally promote the transcription of numerous defense genes encoding glutathione S-transferases, cytochrome P450s, and pathogenesis-related proteins; however, 10-OPEA activity diverges in the context of reduced protease inhibitor transcript accumulation. To identify additional differential responses, we subsequently performed whole transcriptome analyses using RNAseq. These comparisons provide a platform for further examination of plant response specificity to the cyclopentenone 10-OPEA. Overall design: A total of 12 samples were analyzed, comprised of two treatments (10-OPEA and 12-OPDA) and a DMSO carrier control (5%DMSO/0.1%Tween 20 in H20), all in replicates of four.

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Christensen SA, Huffaker A, Kaplan F, Sims J, Ziemann S, Doehlemann G, Ji L, Schmitz RJ, Kolomiets MV, Alborn HT, Mori N, Jander G, Ni X, Sartor RC, Byers S, Abdo Z, Schmelz EA