高粱SbSBP15基因的克隆及分析

Cloning and Analysis of SbSBP15 Gene in Sorghum bicolor

SBP-box (squamosa promoter binding protein, SBP)基因编码一类绿色植物特有的转录因子,它与器官大小的控制、株型、激素和逆境响应等植物重要发育过程密切相关。本研究克隆了高粱SbSBP15基因,对其进行了序列分析、系统进化分析及表达分析。SbSBP15基因编码一个由409个氨基酸组成的蛋白质,含有3个外显子和2个内含子,其SBP结构域位于96~165 aa区域;系统进化显示19个SBP15蛋白可分为4组(Ⅰ~Ⅳ),其中第Ⅰ~Ⅲ组内仅有单子叶植物蛋白,而第Ⅳ组中同时包含有单子叶植物蛋白和双子叶植物蛋白。Sb SBP15与玉米Ub2和Ub3关系最近;启动子序列分析表明,SbSBP15启动子的顺式作用元件包含逆境响应、组织特异性表达以及植物生长发育等相关元件;SbSBP15基因在花后10 d的种子中表达量最高,是苗期根部表达量的18倍;但是随着高粱种子不断发育,SbSBP15表达量逐渐降低,表明SbSBP15可能参与高粱种子发育的过程。本研究为进一步探索SbSBP15的生物学功能奠定了基础。

SBP-box(squamosa promoter bindingprotein,SBP)genes,encodingplant-specific transcription factors,were closely related to many important processes of plant growth,including the control of organ size,plant type,hormones and stresses responses.SbSBP15 was isolated and sequence,phylogenetic,and expression analysis were performed in this study.SbSBP15 gene consists 3 exons and 2 introns and encodes a protein of 409 amino acids,whichcarriedatypicalSBPdomain(96~165aa).Phylogenetictreeindicated,nineteenSBP15proteinswereclustered into four groups(Ⅰ~Ⅳ).Group(Ⅰ~Ⅲ)included monocotyledonous proteins only,while groupⅣcontained both dicotyledonous and monocotyledonous proteins.SbSBP15 had a close phylogenetic relationship with Ub2 and Ub3 in maize.By analyzing the promoter sequence,several cis-elements were identified,including stress response elements,tissue-specific expression elements and plant development related elements,et al.Expression analysis indicated the highest expression level of SbSBP15 was detected in seeds of 10 d after flowering,which was 18 times higher than that in roots at seedling stage.With the development of sorghum seeds,the expression level of SbSBP15 gradually decreased.These results indicated SbSBP15 may be involved in seed development of sorghum.This research lays a foundation for further study on the biological function of SbSBP15.