In order to investigate the molecular biological mechanism involved in germination of soybean young embryos promoted by high temperature( HT) , both young embryos of soybean cultivar"Nipponbare" treated with HT and without HT were employed to screen the differential expression genes with mRNA differential display reverse transcription-polymerase chain reaction (DDRT-PCR). In this study, we reported K6, one of the differential expression genes. K6 was regarded as homologue of Lea5 gene ( soybean cultivar Williams 82 ) , because they shared 99% identical nucleotides. Blastp analysis showes that the putative protein of K6 contains LEA type-3 motifs and is assigned to LEA-3 superfamily. Analysis by CLC Protein workbench 5 software also showes that the putative protein has 113 amino acid residues with relative MW 12. 283 kD and pI 10. 12. The putative protein of K6 has no typical secondary structure element. Results of RT-PCR suggested that expression of K6 gene is constitutive. Expression levels of the gene in soybean young embryos developmental process was relatively constant. Moreover, expressions of the gene were also detected in roots, hypocotyls and leaves.%为了解高温处理促进大豆幼胚萌发成苗的分子生物学机制,采用经典的基因表达差异显示技术,分析大豆品种日本晴高温处理的幼胚与对照组材料的差异表达基因.对其中一个差异表达基因K6进行了测序和比对分析,结果表明该基因序列与大豆Williams 82基因组中的Lea5基因相似度高达99%,可以确定为Lea5基因.Blastp比对分析结果表明大豆Lea5蛋白为LEA-3亚家族成员.利用蛋白质分析软件分析了Lea5基因推测的蛋白质结构的特点,结果表明该蛋白质由113个氨基酸组成,相对分子量为12.283 kD,等电点高达10.12.该蛋白质不形成典型的二级结构.RT-PCR分析表明该基因表达具有组成型特点,在大豆幼胚发育过程中稳定表达,在大豆的根、胚轴和叶片等器官中均有表达.
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