蓖麻基因组Mlo基因家族成员的鉴定及其序列特征分析

Mlo基因家族是一类重要的植物抗病基因，而蓖麻基因组Mlo成员的鉴定和分析为进一步培育蓖麻抗病品种奠定基础。本研究通过系统地分析蓖麻基因组数据，从中共鉴定出16个Mlo成员，其中15个具有完整的ORF，1个序列缺失。对15个具有完整ORF的蓖麻Mlo基因进行结构分析发现，它们在序列长度上差异较大，但其编码蛋白均具有一个保守的Mlo结构域和6~7次跨膜结构，主要定位在细胞膜上。对蓖麻Mlo基因与其他物种的Mlo基因进行聚类关系分析，结果显示，可将蓖麻Mlo基因家族分为7类(Ⅰ~Ⅶ)，其中第Ⅶ类只包含2个蓖麻Mlo基因(RcMlo8和RcMlo9)，这可能是蓖麻中特有的一类Mlo；蓖麻RcMlo3、RcMlo2、RcMlo6和RcMlo12与已知的抗病Mlo基因分别聚在第Ⅳ和第Ⅴ类，这4个基因可能是蓖麻基因组中具有抗病功能的Mlo。本研究结果为进一步克隆蓖麻Mlo基因并研究其功能奠定了良好的基础。

Identification and Sequence Characterization of Mlo Gene Family from the Genome of Riciuns communis L.

Mlo gene family is an important class of plant diseases resistance genes. Identification and sequence characterization of Mlo genes from the genome of castor (Riciuns communis L.) will lay the foundation for breeding for disease resistant varieties in castor. Based on systematic analysis of the genome sequence of Riciuns communis, a total of 16 Mlo genes were identified in this study, of which 15 contained a complete ORF and one partial sequence. Sequence analysis revealed that great difference were observed in the sizes of the 15 genes with complete ORF, however a conserved Mlo domain and 6 to 7 transmembrane domains were found in their corresponding protein sequences. These castor Mlo proteins were mainly located in plasma membrane. Phylogenetic analysis was performed to reveal the evolution of the castor Mlo genes with complete ORF, and Mlo genes from other species. The result indicated that the castor Mlo family could be devided into 7 clades (Ⅰ-Ⅶ). TheⅦclade contained only two castor Mlo genes (RcMlo8 and RcMlo9), which suggested that it might be a specific clade for castor genome. Furthermore, castor RcMlo3, RcMlo2, RcMlo6, and RcMlo12 were grouped into theⅣandⅤclades, which contain the Mlo genes of known function in disease resistance, suggested that the 4 castor Mlo genes might have their functions in disease resistance. These results will provide a good base for further cloning these castor Mlo genes and studying their biological functions.