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小肽分子是植物细胞分化、器官形成和生物防御的重要信号分子.通过分析大豆全基因组DNA序列,发现大量的基因编码小肽前体即小多肽分子.到目前为止,对这些小多肽分子的特征以及功能知之甚少.本文系统地分析了公共数据库中的大豆转录组数据,鉴定了212个在根瘤中增强表达的小多肽基因.其中79个基因属于38个多基因家族,而另外133个基因不属于任何基因家族.在38个基因家族中,有10个基因家族只出现在豆科植物中,另外28个也出现在模式植物拟南芥中.在大豆中,最大的一个基因家族是伤流诱导的小多肽(wound-induced small protein,WIP)基因家族,由38个成员组成,其中一半左右的基因在大豆固氮根瘤中增强表达.我们进一步分析了蒺藜苜蓿、百脉根、拟南芥和水稻中的WIP同源基因,发现部分基因也在根瘤中增强表达或者受病原菌诱导表达.二级结构分析显示,WIP小多肽前体均含有一个DUF3774结构域,其中包含2个跨膜疏水区域,多数分子具有N-端信号肽序列.我们选取了2个大豆WIP基因进行亚细胞定位分析,发现WIP小多肽定位于细胞膜上.有趣的是,34个大豆WIP基因成簇分布在3条染色体上,与目前发现的其他小多肽基因家族的分散分布(如CLE)完全不同.在6,12和13号染色体上分别分布有11,12和11个WIP基因.而在12号染色体上的WIP同源基因则位于13号染色体上,二者呈对应关系.而6号染色体上的WIP基因相互之间同源性最高,且只与12号染色体上的基因具有较高的同源性.因此,可以推测,在大豆基因组中WIP基因可能起源13号染色体,通过染色体复制扩散至12号染色体,再扩散到6号染色体.而在拟南芥和水稻基因组中,半数以上的WIP基因也分布在一条染色体上,且与大豆12和13号染色体上的WIP基因具有较高的同源性.因此,植物中WIP基因可能来源一个共同的祖先.
Small peptide molecules are important signal molecules in plant cell differentiation, organogenesis and biological defense.Based on the analysis of the whole genome DNA sequence of soybean, it is found that a large number of genes encode small peptide precursors, ie, small polypeptide molecules.So far, Characteristics and functions of this gene.This paper systematically analyzes the data of soybean transcriptome in a public database and identifies 212 small polypeptide genes that are strongly expressed in nodules, of which 79 genes belong to 38 multigene families and the other 133 Genes do not belong to any gene family.In the 38 gene families, 10 gene families appear only in legumes, and the other 28 also appear in the model plant Arabidopsis.In soybean, the largest one gene family is The wound-induced small protein (WIP) gene family consisted of 38 members, of which about half of the genes were strongly expressed in soybean-nitrogen-fixing nodules. We further analyzed the effects of Medicago truncatula, Lotus japonicus, Arabidopsis and rice WIP homologous genes and found that some genes are also enhanced expression in root nodules or induced by pathogenic bacteria secondary structure analysis showed that before WIP small peptides The body contains a DUF3774 domain, which contains two transmembrane hydrophobic regions, most of the molecules have N-terminal signal peptide sequence.We selected two soybean WIP gene subcellular localization analysis and found WIP small polypeptide located in the cell membrane. Interestingly, the WIP genes of 34 soybean populations are clustered on 3 chromosomes and are completely different from the distributions (such as CLE) of the other small polypeptide gene families that are currently found, and are distributed on chromosomes 6, 12 and 13, respectively , 12 and 11 WIP genes, while the WIP homology gene on chromosome 12 is located on chromosome 13. The WIP genes on chromosome 6 have the highest homology with each other and only Therefore, it is speculated that in the soybean genome, the WIP gene may originate from chromosome 13, diffused through chromosome 12 to chromosome 12, and then spread to chromosome 6. In More than half of the WIP genes in Arabidopsis and rice genomes are also distributed on one chromosome and have high homology to the WIP genes on chromosomes 12 and 13. Therefore, the WIP genes in plants may originate from a common Ancestors .