The allene oxide cyclase of barley (Hordeum vulgare L.) - Cloning and organ-specific expression

Helmut Maucher, Irene Stenzel, Otto Miersch, Niels Stein, Manoj Prasad, Uwe Zierold, Patrick Schweizer, Conrad Dorer, Bettina Hause, Claus Wasternack

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

The naturally occurring enantiomer of the various octadecanoids and jasmonates is established in a biosynthetic step catalyzed by the allene oxide cyclase (AOC). The AOC converts an allene oxide formed by an allene oxide synthase (AOS). Here, we show cloning and characterization of cDNAs encoding the AOC and a third AOS, respectively, in addition to the two AOSs previously published (Plant J. 21, 199-213, 2000). The ORF of the AOC-cDNA of 717 bp codes for a protein of 238 amino acid residues carrying a putative chloroplast target sequence. Overexpression without chloroplast target sequence revealed AOC activity. The AOC was found to be a single copy gene which mapped on chromosome 6H. AOC mRNA accumulation appeared in leaf segments upon treatment with various jasmonates, octadecanoids and ABA or during stress such as treatment with sorbitol or glucose solutions. Infection with powdery mildew activated AOC expression in susceptible and resistant lines of barley which correlated with PR1b expression. Among different tissues of barley seedlings, the scutellar node and leaf base accumulated AOC mRNA preferentially which correlated with accumulation of mRNAs for other biosynthetic enzymes (lipoxygenases, AOSs). AOC mRNA accumulation appeared also abundantly in parts of the root containing the tip and correlated with elevated levels of jasmonates. The data suggest a link of AOC expression and JA formation and support role of JA in stress responses and development of barley.

Original languageEnglish
Pages (from-to)801-811
Number of pages11
JournalPhytochemistry
Volume65
Issue number7
DOIs
Publication statusPublished - Apr 2004
Externally publishedYes

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