The expression level of threonine synthase and cystathionine-γ-synthase is influenced by the level of both threonine and methionine in Arabidopsis plants

被引:18
作者
Avraham, T
Amir, R
机构
[1] Migal Galilee Technol Ctr, Plant Sci Lab, IL-11016 Kiryat Shmona, Israel
[2] Tel Hai Acad Coll, IL-10120 Upper Galilee, Israel
基金
以色列科学基金会;
关键词
amino acid biosynthesis; cystathionine-gamma-synthase; essential amino acids; methionine; threonine; threonine synthase;
D O I
10.1007/s11248-005-0273-4
中图分类号
Q5 [生物化学];
学科分类号
071010 ; 081704 ;
摘要
The biosynthesis pathways of the essential amino acids methionine and threonine diverge from O-phosphohomoserine, an intermediate metabolite in the aspartate family of amino acids. Thus, the enzymes cystathionine-gamma-synthase (CGS) in the methionine pathway and threonine synthase (TS), the last enzyme in the threonine pathway, compete for this common substrate. To study this branching point, we overexpressed TS in sense and antisense orientation in Arabidopsis plants with the aim to study its effect on the level of threonine but more importantly on the methionine content. Positive correlation was found not only between TS expression level and threonine content, but also between TS/threonine and CGS expression level. Plants expressing the sense orientation of TS showed a higher level of threonine, increased expression level of CGS, and a significantly higher level of S-methylmethionine, the transport form of methionine. By contrast, plants expressing the antisense form of TS showed lower levels of threonine and of CGS expression level. In these antisense plants, the methionine level increased up to 47-fold compared to wild-type plants. To study further the effect of threonine on CGS expression level, wild-type plants were irrigated with threonine and control plants were irrigated with methionine or water. While threonine increased the expression level of CGS but reduced that of TS, methionine reduced the expression level of CGS but increased that of TS. This data demonstrate that both methionine and threonine affect the two enzymes at the branching point, thus controlling not only their own level, but also the level of each other. This mechanism probably aids in keeping the levels of these two essential amino acids sufficiently high to support plant growth.
引用
收藏
页码:299 / 311
页数:13
相关论文
共 34 条
[1]   Cystathionine γ-synthase and threonine synthase operate in concert to regulate carbon flow towards methionine in plants [J].
Amir, R ;
Hacham, Y ;
Galili, G .
TRENDS IN PLANT SCIENCE, 2002, 7 (04) :153-156
[2]   Enhanced levels of methionine and cysteine in transgenic alfalfa (Medicago sativa L.) plants over-expressing the Arabidopsis cystathionine γ-synthase gene [J].
Avraham, T ;
Badani, H ;
Galili, S ;
Amir, R .
PLANT BIOTECHNOLOGY JOURNAL, 2005, 3 (01) :71-79
[3]   The biosynthesis and metabolism of the aspartate derived amino acids in higher plants [J].
Azevedo, RA ;
Arruda, P ;
Turner, WL ;
Lea, PJ .
PHYTOCHEMISTRY, 1997, 46 (03) :395-419
[4]   Mutation in the threonine synthase gene results in an over-accumulation of soluble methionine in Arabidopsis [J].
Bartlem, D ;
Lambein, I ;
Okamoto, T ;
Itaya, A ;
Uda, Y ;
Kijima, F ;
Tamaki, Y ;
Nambara, E ;
Naito, S .
PLANT PHYSIOLOGY, 2000, 123 (01) :101-110
[5]   SEPARATION AND ESTIMATION OF AMINO ACIDS IN CRUDE PLANT EXTRACTS BY THIN-LAYER ELECTROPHORESIS AND CHROMATOGRAPHY [J].
BIELESKI, RL ;
TURNER, NA .
ANALYTICAL BIOCHEMISTRY, 1966, 17 (02) :278-&
[6]   ASPARTATE KINASE AND SYNTHESIS OF ASPARTATE-DERIVED AMINO-ACIDS IN WHEAT [J].
BRIGHT, SWJ ;
SHEWRY, PR ;
MIFLIN, BJ .
PLANTA, 1978, 139 (02) :119-125
[7]   Evidence for autoregulation of cystathionine γ-synthase mRNA stability in Arabidopsis [J].
Chiba, Y ;
Ishikawa, M ;
Kijima, F ;
Tyson, RH ;
Kim, J ;
Yamamoto, A ;
Nambara, E ;
Leustek, T ;
Wallsgrove, RM ;
Naito, S .
SCIENCE, 1999, 286 (5443) :1371-1374
[8]   S-adenosyl-L-methionine is an effector in the posttranscriptional autoregulation of the cystathionine γ-synthase gene in Arabidopsis [J].
Chiba, Y ;
Sakurai, R ;
Yoshino, M ;
Ominato, K ;
Ishikawa, M ;
Onouchi, H ;
Naito, S .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2003, 100 (18) :10225-10230
[9]   Floral dip:: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana [J].
Clough, SJ ;
Bent, AF .
PLANT JOURNAL, 1998, 16 (06) :735-743
[10]  
Coruzzi G, 2000, BIOCH MOL BIOL PLANT, P358