Zou Li-Ping, Li Han-Xia, Ouyang Bo, Zhang Jun-Hong, Ye Zhi-Biao
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
Yi Chuan Xue Bao. 2006 Aug;33(8):757-64. doi: 10.1016/S0379-4172(06)60108-X.
GDP-D-mannose pyrophosphorylase (GMP, EC 2.7.7.22) catalyzes the synthesis of GDP-D-mannose and represents the first committed step in plant ascorbic acid biosynthesis. Using potato GMP cDNA sequence as a querying probe, 65 highly homologous tomato ESTs were obtained from dbEST of GenBank and the putative cDNA sequence of tomato GMP was assembled. The full-length GMP cDNA of tomato was cloned by RACE-PCR with primers designed according to the assembled cDNA sequence. The full-length cDNA sequence contained a complete open reading frame (ORF) of 1,086 bp, which encoded 361 amino acid residues. This gene was designated as LeGMP (GenBank accession No. AY605668). Homology analysis of LeGMP showed a 96% identity with potato GMP and the deduced amino acid showed 99%, 97%, 91% and 89% homology with GMP from potato, tobacco, alfalfa and Arabidopsis thaliana, respectively. Northern blot analysis showed that LeGMP was constitutively expressed in roots, stems, leaves, flowers and fruits of tomato; but the expression levels varied. LeGMP was mapped to 3-D using 75 tomato introgression lines (ILs), each containing a single homozygous RFLP-defined chromosome segment from the green-fruited species Lycopersicon pennellii.
GDP - D - 甘露糖焦磷酸化酶（GMP，EC 2.7.7.22）催化GDP - D - 甘露糖的合成，是植物抗坏血酸生物合成中的首个关键步骤。以马铃薯GMP cDNA序列为查询探针，从GenBank的dbEST中获得了65个高度同源的番茄ESTs，并拼接出了番茄GMP的推定cDNA序列。根据拼接的cDNA序列设计引物，通过RACE - PCR克隆了番茄GMP的全长cDNA。该全长cDNA序列包含一个1086 bp的完整开放阅读框（ORF），编码361个氨基酸残基。该基因被命名为LeGMP（GenBank登录号：AY605668）。LeGMP的同源性分析表明，它与马铃薯GMP的一致性为96%，推导的氨基酸序列与马铃薯、烟草、苜蓿和拟南芥的GMP同源性分别为99%、97%、91%和89%。Northern杂交分析表明，LeGMP在番茄的根、茎、叶、花和果实中组成型表达，但表达水平有所不同。利用75个番茄渐渗系（ILs）将LeGMP定位到3 - D，每个渐渗系都包含来自绿果种彭奈利番茄（Lycopersicon pennellii）的一个纯合RFLP定义的染色体片段。
