Elevated tyrosine decarboxylase and tyramine hydroxycinnamoyltransferase levels increase wound-induced tyramine-derived hydroxycinnamic acid amide accumulation in transgenic tobacco leaves.
Feruloyltyramine (FT) and 4-coumaroyltyramine (4CT) participate in the defense of plants against pathogens through their extracellular peroxidative polymerization, which is thought to reduce cell wall digestibility. Hydroxycinnamoyl-CoA:tyramine N-(hydroxycinnamoyl)transferase (THT; EC 2.3.1.110) and tyrosine decarboxylase (TYDC; EC 4.1.1.25) are purported to play key roles in the stress-induced regulation of tyramine-derived hydroxycinnamic acid amide (HCAAT) metabolism. Transgenic tobacco (Nicotiana tabacum cv. Xanthi) was engineered to constitutively express tobacco THT. A T1 plant over-expressing THT was crossbred with T1 tobacco expressing opium poppy TYDC2, to produce a T2 line with elevated THT and TYDC activities compared with wild type plants. The effects of an independent increase in TYDC or THT activity, or a dual increase in both TYDC and THT on the cellular pools of HCAAT pathway intermediates and the accumulation of soluble and cell wall-bound FT and 4CT were examined. Increased TYDC activity resulted in a larger cellular pool of tyramine and lower levels of L-phenylalanine in transgenic leaves. In contrast, elevated THT activity reduced tyramine levels. HCAAT levels were low in healthy leaves, but were induced in response to wounding and accumulated around wound sites. Similarly, endogenous THT and TYDC activities were wound-induced. The rate of wound-induced HCAAT accumulation was highest in transgenic plants with elevated THT and TYDC activities showing that both enzymes exert control over the flux of intermediates involved in HCAAT biosynthesis under some conditions.
Hagel
Jillian M
JM
Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
Facchini
Peter J
PJ
D000217:Acyltransferases / Q000378:metabolism*; D000577:Amides / Q000378:metabolism; D003373:Coumaric Acids / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics; D014439:Tyramine / Q000378:metabolism*; D014445:Tyrosine Decarboxylase / Q000378:metabolism*
D000577:Amides; D003373:Coumaric Acids; D000217:Acyltransferases; C108168:hydroxycinnamoyl-CoA-tyramine N-(hydroxycinnamoyl)transferase; D014445:Tyrosine Decarboxylase; D014439:Tyramine
J Biol Chem. 1994 Oct 28;269(43):26684-90
7929401
Plant Cell Physiol. 2001 May;42(5):475-81
11382813
Biosci Biotechnol Biochem. 2000 May;64(5):1025-31
10879473
Eur J Biochem. 1999 Aug;263(3):686-94
10469131
Plant Physiol. 1996 May;111(1):259-267
12226290
J Biol Chem. 1993 Jan 25;268(3):2189-94
8420986
J Biol Chem. 1999 Feb 12;274(7):4273-80
9933628
Anal Biochem. 1987 May 15;163(1):16-20
2441623
Plant Physiol. 1993 Oct;103(2):329-334
12231940
J Biol Chem. 1995 Mar 31;270(13):7382-6
7706282
Eur J Biochem. 1997 Aug 1;247(3):1127-35
9288939
Plant Mol Biol. 1993 Jan;21(2):385-9
8425063
Plant Physiol. 1996 Sep;112(1):183-192
12226384
Planta. 1987 Dec;172(4):494-501
24226068
Plant Physiol. 2004 May;135(1):346-56
15122017
Plant Cell. 1995 Nov;7(11):1787-1799
12242360
J Biol Chem. 2003 Oct 31;278(44):43373-83
12900412
Plant Physiol. 1996 Sep;112(1):193-205
8819324
Mol Plant Microbe Interact. 2001 Jun;14(6):785-92
11386374
Proc Natl Acad Sci U S A. 1994 Aug 2;91(16):7608-12
8052628
Pharmacol Biochem Behav. 1991 Nov;40(3):465-9
1806939
Plant Physiol. 2000 Mar;122(3):933-43
10712558
Biochem Biophys Res Commun. 2002 Apr 12;292(4):1104-10
11944930
Planta. 1999 Jul;209(1):33-44
10467029
Phytochemistry. 1998 Mar;47(6):915-33
11536868
Anal Biochem. 1976 May 7;72:248-54
942051
Plant Cell. 1989 Oct;1(10):993-1001
12359883
Plant Physiol. 1999 Jul;120(3):653-64
10398700