从石蒜[ Lycoris radiata ( L’ Hér.) Herb.]叶片全长cDNA文库中克隆获得Mg2+转运体( MGT)基因LrMGT。序列分析结果显示：LrMGT基因的cDNA序列全长1726 bp,其中开放阅读框( ORF)长度921 bp,编码306个氨基酸。石蒜LrMGT基因编码的氨基酸序列的理论相对分子质量为33635,理论等电点为pI 5.14,为疏水性膜蛋白,不具有信号肽。序列比对结果表明：石蒜LrMGT基因编码的氨基酸序列与小米[ Setaria italica ( Linn.) Beauv.]、水稻( Oryza sativa Linn.)和拟南芥[ Arabidopsis thaliana ( Linn.) Heynh.]等植物的MGT基因编码的氨基酸序列的相似性较高,相似度达到72%~76%；石蒜LrMGT基因与其他植物MGT基因编码的氨基酸序列的保守区域较大,均具有较高的保守性。在 NJ 系统树上石蒜 LrMGT 基因编码的氨基酸序列与禾本科( Gramineae )植物二穗短柄草[ Brachypodium distachyum ( Linn.) Beauv.]、水稻、高粱[ Sorghum bicolor ( Linn.) Moench]和小米MGT基因编码的氨基酸序列聚为同一个分支,表明它们可能具有较近的进化关系。实时荧光定量PCR结果表明：石蒜LrMGT基因在根和鳞茎中的相对表达量较高,在叶片和花中的相对表达量较低,具有明显的组织特异性。%Mg2+ transporter ( MGT) gene LrMGT was cloned from the full-length cDNA library in leaf of Lycoris radiata ( L’ Hér.) Herb. Result of sequence analysis shows that the full-length of cDNA sequence of LrMGT gene is 1 726 bp with an open reading frame ( ORF) of 921 bp, which encodes 306 amino acids. The theoretical relative molecular weight of the amino acid sequence encoded by LrMGT gene from L. radiata is 33 635 and its theoretical isoelectric point is pI 5. 14, and which is hydrophobic membrane protein without signal peptide. The result of sequence alignment shows that amino acid sequence encoded by LrMGT gene from L. radiata possesses higher similarity to those encoded by MGT gene from Setaria italica ( Linn.) Beauv., Oryza sativa Linn. and Arabidopsis thaliana ( Linn.) Heynh., etc, with similarity degree of 72%-76%. There is large conserved region in all of the amino acid sequences encoded by LrMGT gene from L. radiata and MGT gene from other species, which possess high conservation. In NJ phylogenetic tree, the amino acid sequences encoded by LrMGT gene from L. radiata and by MGT gene from other species in Gramineae such as Brachypodium distachyum ( Linn.) Beauv., O. sativa, Sorghum bicolor ( Linn.) Moench and S. italica are clustered together, meaning that these species have the closer evolution relationship. The real-time fluorescence quantitative PCR result shows that the relative expression of LrMGT gene from L. radiata is higher in root and bulb and lower in leaf and flower with an obvious tissue specificity.
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