Cloning and characterization of a coronatine-regulated tyrosine aminotransferase from Arabidopsis.
In plants, the phytotoxin coronatine, which is an analog of the octadecanoids 12-oxo-phytodienoic acid and/or jasmonic acid, gives rise to a number of physiological responses similar to those of octadecanoids. To further elucidate the physiological role of these compounds, the differential RNA display technique was used to isolate a number of novel octadecanoid-inducible genes expressed in coronatine-treated Arabidopsis. Among these, a cDNA clone was identified that was similar to known tyrosine aminotransferases (TATs). The function was verified with the expressed recombinant protein. In Arabidopsis, the protein is present as a multimer of 98 kD, with a monomer of an apparent molecular mass of 47 kD. TAT mRNA could be induced within 2 h by various octadecanoids and by wounding of the plants. Accumulation of the TAT protein and a 5- to 7-fold increase in its enzymatic activity was observed 7 to 9 h after application of octadecanoids, coronatine, or wounding. The potential role of TAT in the defense response to herbivores and pathogens is discussed.
Lopukhina
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A
Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität, D-44780 Bochum, Germany.
Dettenberg
M
M
Weiler
E W
EW
Holländer-Czytko
H
H
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000502:physiology*; D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006801:Humans; D007192:Indenes; D008969:Molecular Sequence Data; D010935:Plant Diseases; D012333:RNA, Messenger; D018749:RNA, Plant; D013229:Stearic Acids / Q000378:metabolism / Q000494:pharmacology; D014444:Tyrosine Transaminase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D000596:Amino Acids; D018076:DNA, Complementary; D018744:DNA, Plant; D007192:Indenes; D012333:RNA, Messenger; D018749:RNA, Plant; D013229:Stearic Acids; C058487:coronatine; D014444:Tyrosine Transaminase