西瓜防御素(ClPDF)基因挖掘及序列分析

Gene Mining and Sequence Analysis of Plant Defensins in Citrullus lanatus

为明确西瓜防御素基因(ClPDF)的结构和功能,采用生物信息学方法对西瓜防御素基因进行了详细的全基因组挖掘和序列分析。结果表明,从西瓜基因组中共获得7个防御素基因,ClPDFs基因编码的氨基酸序列都含有高度保守的8个半胱氨酸、1个甘氨酸、1个丝氨酸和1个芳香族氨基酸残基。分析发现,ClPDFs基因在理化性质上有一定的差异。系统进化分析说明,ClPDFs与拟南芥PDF2基因家族聚为一类。二级结构预测结果说明,所有ClPDFs序列均以不规则卷曲为主要组成元件,在延伸链和α-螺旋组成上存在差异。信号肽和跨膜结构预测结果相似,仅有1条序列无信号肽,1条序列有跨膜区,而其他序列都含有信号肽、无跨膜区。证明了西瓜防御素基因为多基因家族,都含有高度保守的结构域,但在结构上西瓜防御素基因差异较大,为进一步探讨西瓜防御素ClPDFs的生物功能奠定了基础。

To clarify the structure and functional characterization of defensin genes in watermelon,this work adopted the bioinformatics methods to analyze the watermelon defensin gene family and sequence characteristics in detail based the fully sequenced watermelon genome.The results showed that a family of 7 watermelon defensin（ClPDF） genes was discovered by genome sequence analysis in watermelon.Alignment of ClPDFs showed the presence of highly conserved eight cysteines,a glycine residue,a serine and an aromatic residue.Phylogenetic analysis revealed that ClPDFs belonged to Arabidopsis PDF2 gene cluster.ClPDFs proteins were found varies in structures.Secondary structure assay showed that random coil is the main composition,whereas the percent of extended strand and alpha helix has some differences.SignalP analysis result parallels with that of TMHMM,namely,except for other six genes,only one gene without signal peptide and one gene has the transmembrane segment.This work proved that defensin genes were multiple gene family in watermelon genome,and all the watermelon defensin genes contained the highly conserved domain but exhibited significant differences in structure characteristics among watermelon defenses,This work will provide foundation for the identification of biological functions of watermelon difensins.