Xie Guo-Sheng, Liu Shen-Kui, Takano Tetsuo, You Zong-Bin, Zhang Duan-Pin
Department of Agronomy, National Key Lab of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Yi Chuan Xue Bao. 2002 Dec;29(12):1078-84.
VB12-independent methionine synthase is present in higher plants, and catalyzes the methylation of C-homocysteine to form methionine, which is very important for methylation reactions and syntheses of polyamines and ethylene. Under the alkaline condition, using cDNA-RAPD method, a new VB12-independent methionine synthase gene has been cloned and characterized for the first time in rice in this study. The results exhibited that, the cDNA gene entailed 2740 bp, had single copy in the rice genome and encoded peptide of 765 amino acids, the peptide showed 92% and 83% identity with that from Mesembryanthemum cystallinum (U84889) and Cathararanthus roseus (X83499), respectively. It enhanced the transcription more greatly after sodium carbonate treatment for 12 h and 24 h than that of sodium chloride treatment, and then obviously reduced in 48 h later, suggesting that it is related to this stress tolerance in rice.
不依赖维生素B12的蛋氨酸合酶存在于高等植物中，催化高半胱氨酸甲基化形成蛋氨酸，这对甲基化反应以及多胺和乙烯的合成非常重要。在碱性条件下，本研究首次采用cDNA-RAPD方法在水稻中克隆并鉴定了一个新的不依赖维生素B12的蛋氨酸合酶基因。结果表明，该cDNA基因全长2740 bp，在水稻基因组中为单拷贝，编码765个氨基酸的肽段，该肽段与水晶冰花（U84889）和长春花（X83499）的相应肽段分别具有92%和83%的同源性。碳酸钠处理12小时和24小时后，其转录增强程度大于氯化钠处理，48小时后明显降低，表明它与水稻的这种胁迫耐受性有关。
