半夏属植物凝集素同其他天南星科植物凝集素一样,有3个甘露糖专一结合位点,且具显著的抗虫性.本研究根据已知掌叶半夏凝集素基因表达序列的相关信息设计引物,采用RT-PCR方法,分别从滴水珠、石蜘蛛、盾叶半夏、掌叶半夏、三叶半夏中克隆出长约530bp的凝集素基因片段.使用Genesean软件、ORF finder软件、Ex2PASy Proteomics Server软件对5个凝集素基因片段进行分析,结果表明:克隆出的滴水珠、石蜘蛛、盾叶半夏、掌叶半夏、三叶半夏凝集素基因片段分别编码107、171、170、170、170个氨基酸,在它们所编码的肽链中,都具有酪蛋白激酶Ⅱ磷酸化位点、蛋白激酶C磷酸化位点和N-糖基化位点三类不同的功能位点.但由于编码序列碱基的突变,引起肽链中的氨基酸发生变化,从而导致这五种植株的凝集素基因存在较高的多态性以及存在功能位点的差异.其凝集素基因多态性及功能位点的差异对凝集素功能的影响需进一步分析.本实验为克隆五种植物凝集素基因的表达序列与结构基因以及深入研究半夏属凝集素的功能提供了有意义的参考资料.%Pinellia leetin, a mannose binding lectin with three mannose binding boxes like lectins from other Araceae species, has obvious insect resistance. A pair of primers was designed according to correlative information of Lection gene in P. Pedatisecta. About 530bp eDNA fragments of Lection gene in P. ternata, P. Pedatisecta, P.cordata, P. inlegrifolia, P. peltata were cloned by RT-PCR. These partial sequences data were analyzed by GenScan software, ORF finder software, ExPASy Proteomics Server software. The results showed that the partial sequences of lectin gene encode 170 amino acids in P. ternata, 171 amino acids in P. Pedatisecta, 170 amino acids in P. cordata, 171 amino acids in P. inlegrifolia and 170 amino acids in P. peltata. Three functional sites were found in the five peptide chains, namely, protein kinase C phosphorylation site, Casein kinase Ⅱ phosphorylation site and N - myristoylation site, respectively. As the mutation of nueleotide may cause the changes of amino-acids in peptide chains, furthermore lead to a high protein polymorphism and differences functional site. It needs further study to investigate how the high protein polymorphism would affect the function of lectin gene. Our studies provide significant reference for cloning expressed sequence and structural gene of lectin gene in five species, as well as studding the function of lectin gene from Pinellia.
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