The Rhizobium etli metZ gene is essential for methionine biosynthesis and nodulation of Phaseolus vulgaris.
The Rhizobium etli metZ gene is essential for methionine biosynthesis and nodulation of Phaseolus vulgaris.
复制标题
根瘤菌 metZ 基因对于菜豆的甲硫氨酸生物合成和结瘤至关重要。
DOI：
10.1094/mpmi.1999.12.1.24
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
E. Patriarca
中科院分区：
文献类型：
--
作者：
R. Tatè;A. Riccio;Emilia Caputo;M. Laccarino;E. Patriarca
从etli根瘤菌中分离到一株突变株CTNUX 23，该突变株携带Tn 5，不能以硫酸盐为唯一硫源生长。序列分析表明，Tn 5插入到一个梅斯（O-琥珀酰高丝氨酸硫化氢解酶）同源基因中。CTNUX 23突变株具有对甲硫氨酸的生长依赖性，尽管胱硫醚或高半胱氨酸而不是高丝氨酸或O-琥珀酰高丝氨酸允许突变株生长。RNA酶保护试验表明，metZ样基因在蛋氨酸或半胱氨酸生长的细胞中具有基础水平的表达，这是诱导时，使用硫酸盐或硫代硫酸盐。从亲本野生型菌株CE 3中克隆了梅斯基因，转化后得到的质粒pAR 204缓解了两株R. etli和PAO 503（梅斯）。与菌株CE 3或CTNUX 23（pAR 204）不同，菌株CTNUX 23显示出不可检测水平的O-琥珀酰高丝氨酸硫化氢解酶活性。菌株CTNUX 23不能产生类黄酮诱导的脂几丁质寡糖（结瘤因子）或诱导根瘤或根瘤状结构的菜豆的根上，除非蛋氨酸被添加到生长培养基中。这些数据和我们以前的结果支持这样的观点，即半胱氨酸或谷胱甘肽，而不是蛋氨酸，是由根细胞提供给植物内部生长的细菌的。
A mutant strain (CTNUX23) of Rhizobium etli carrying Tn5 unable to grow with sulfate as the sole sulfur source was isolated and characterized. Sequence analysis showed that Tn5 is inserted into a metZ (O-succinylhomoserine sulfhydrylase)-homologous gene. The CTNUX23 mutant strain had a growth dependency for methionine, although cystathionine or homocysteine, but not homoserine or O-succinylhomoserine, allowed growth of the mutant. RNase protection assays showed that the metZ-like gene had a basal level of expression in methionine- or cysteine-grown cells, which was induced when sulfate or thiosulfate was used. The metZ gene was cloned from the parent wild-type strain, CE3, and the resulting plasmid pAR204 relieved, after transformation, the methionine auxotrophy of both strains CTNUX23 of R. etli and PAO503(metZ) of Pseudomonas aeruginosa. Unlike strain CE3 or CTNUX23 (pAR204), strain CTNUX23 showed undetectable levels of O-succinylhomoserine sulfhydrylase activity. Strain CTNUX23 was unable to produce flavonoid-inducible lipo-chitin oligosaccharides (Nod factors) or to induce nodules or nodulelike structures on the roots of Phaseolus vulgaris, unless methionine was added to the growth medium. These data and our previous results support the notion that cysteine or glutathione, but not methionine, is supplied by the root cells to bacteria growing inside the plant.
DOI：
10.1094/mpmi-5-072
发表时间：
1992
期刊：
Molecular plant-microbe interactions : MPMI
影响因子：
--
作者：
H. Spaink;A. Aarts;G. Stacey;G. Bloemberg;B. Lugtenberg;E. P. Kennedy
通讯作者：
H. Spaink;A. Aarts;G. Stacey;G. Bloemberg;B. Lugtenberg;E. P. Kennedy