Overexpression of a heterologous sam gene encoding S-adenosylmethionine synthetase in flax (Linum usitatissimum) cells:: Consequences on methylation of lignin precursors and pectins
Overexpression of a heterologous sam gene encoding S-adenosylmethionine synthetase in flax (Linum usitatissimum) cells:: Consequences on methylation of lignin precursors and pectins
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DOI：
10.1034/j.1399-3054.2001.1120211.x
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发表时间：
2001-06-01
影响因子：
6.4
通讯作者：
David, A
中科院分区：
文献类型：
--
作者：
Lamblin, F;Saladin, G;David, A
利用根癌农杆菌将编码S-腺苷甲硫氨酸合成酶(EC 2.5.1.6)的SAM1基因转入亚麻细胞，该酶催化甲硫氨酸转化为活细胞中主要的甲基供体S-腺苷甲硫氨酸(SAI)。本工作旨在研究转基因细胞中腺苷甲硫氨酸合成酶(SAM-S)活性升高对果胶单体和二甲氧基化木质素产量及果胶甲酯化程度的影响。在35S启动子和nptII基因的控制下，将含有Sam1基因的双元载体pO35SSAM的根癌农杆菌GV3101(PGV2260)与根癌农杆菌GV3101(PGV2260)共培养，筛选转化细胞。大多数转基因细胞株的SAM-S活性比对照显著提高(最高可达3.2倍)。结果表明，对于所分析的细胞系，这种转化对咖啡酸O-甲基转移酶的体外活性、木质素前体或木质素沉积的甲氧基化程度、体外果胶甲基转移酶的活性、果胶甲基转移酶的活性没有影响但导致了易碎和快速生长的转基因细胞系中果胶甲酯化的增加。
The Arabidopsis thaliana sam1 gene encoding S-adenosylmethionine synthetase (EC 2.5.1.6) was transferred to flax (Linum usitatissimum) cells via Agrobacterium tumefaciens, This enzyme catalyses the conversion of methionine to S-adenosylmethionine (SARI), the major methyl group donor in living cells, The aim of this work was to study the consequences of an increased SAM-synthetase (SAM-S) activity in transgenic cell lines on both the production of mono- and dimethoxylated lignin monomers and the degree of methylesterification of pectins, Hypocotyls were cocultivated with Agrobacterium tumefaciens strain GV3101 (pGV2260) harbouring the pO35SSAM binary vector carrying the sam1 gene under the control of the 35S promoter and the nptII gene for selection of putative transformed cells, Most of the transgenic cell lines exhibited a significant (up to 3.2-fold) increase in SAM-S activity compared to the controls, The results showed that for the cell lines analysed this transformation had no effect on caffeic acid O-methyltransferase (COMT, EC 2.1.1.68) in vitro activity, degree of methoxylation of lignin precursors or lignin deposition, pectin methyltransferase (PMT, EC 2.1.1) in vitro activity, but led to an increase of pectin methylesterification in friable and fast-growing transgenic cell lines.