The maize brown midrib2 (bm2) gene encodes a methylenetetrahydrofolate reductase that contributes to lignin accumulation.
The maize brown midrib2 (bm2) gene encodes a methylenetetrahydrofolate reductase that contributes to lignin accumulation.
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DOI：
10.1111/tpj.12394
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Schnable PS
中科院分区：
文献类型：
--
作者：
Tang HM;Liu S;Hill-Skinner S;Wu W;Reed D;Yeh CT;Nettleton D;Schnable PS
玉米棕色中脉突变体的中脉呈现红棕色，这与木质素浓度的降低和木质素组成的改变有关。在这里，我们报告了bm 2基因的定位，克隆，功能和生化分析。bm 2基因被定位到1号染色体的一个小区域，该区域含有一个假定的亚甲基四氢叶酸还原酶（MTHFR）基因，该基因在bm 2突变体植物中下调。对多个Mu诱导的bm 2-Mu突变等位基因的分析证实了该组成型表达基因是bm 2。酵母互补实验和先前发表的生化表征表明，bm 2基因编码的功能MTHFR。定量RT-PCR分析表明，bm 2突变体积累的bm 2转录水平大大降低。预期MTHFR功能的改变会影响甲基供体S-腺苷-L-甲硫氨酸（SAM）的积累。因为SAM被木质素途径中的两种甲基转移酶消耗（Ye等人，1994），bm 2编码功能性MTHFR的发现与其木质素表型一致。与bm 2的这种功能分配一致，在bm 2突变体中改变了多种SAM依赖性或相关途径（包括木质素生物合成）中的基因表达模式。生物化学分析证实，与野生型相比，bm 2突变体积累的木质素水平降低，组合物改变。因此，这项研究表明MTHFR在木质素生物合成中的作用。
The midribs of maize brown midrib (bm) mutants exhibit a reddish-brown color associated with reductions in lignin concentration and alterations in lignin composition. Here, we report the mapping, cloning, and functional and biochemical analyses of the bm2 gene. The bm2 gene was mapped to a small region of chromosome 1 that contains a putative methylenetetrahydrofolate reductase (MTHFR) gene, which is down-regulated in bm2 mutant plants. Analyses of multiple Mu-induced bm2-Mu mutant alleles confirmed that this constitutively expressed gene is bm2. Yeast complementation experiments and a previously published biochemical characterization show that the bm2 gene encodes a functional MTHFR. Quantitative RT-PCR analyses demonstrated that the bm2 mutants accumulate substantially reduced levels of bm2 transcript. Alteration of MTHFR function is expected to influence accumulation of the methyl donor S-adenosyl-l-methionine (SAM). Because SAM is consumed by two methyltransferases in the lignin pathway (Ye et al., 1994), the finding that bm2 encodes a functional MTHFR is consistent with its lignin phenotype. Consistent with this functional assignment of bm2, the expression patterns of genes in a variety of SAM-dependent or -related pathways, including lignin biosynthesis, are altered in the bm2 mutant. Biochemical assays confirmed that bm2 mutants accumulate reduced levels of lignin with altered composition compared to wild-type. Hence, this study demonstrates a role for MTHFR in lignin biosynthesis.
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影响因子：
14.9
作者：
Millevoi S;Vagner S
通讯作者：
Vagner S
影响因子：
6.1
作者：
Marita, JM;Vermerris, W;Hatfield, RD
通讯作者：
Hatfield, RD
DOI：
10.1515/1544-6115.1826
发表时间：
2012-01-01
影响因子：
0.9
作者：
Lund, Steven P.;Nettleton, Dan;Smyth, Gordon K.
通讯作者：
Smyth, Gordon K.
影响因子：
7.4
作者：
Lawrence, CJ;Seigfried, TE;Brendel, V
通讯作者：
Brendel, V
DOI：
10.1111/j.2517-6161.1995.tb02031.x
发表时间：
1995-01-01
影响因子：
5.8
作者：
BENJAMINI, Y;HOCHBERG, Y
通讯作者：
HOCHBERG, Y