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蔗糖合酶(sucrose synthase)与植物库强调节、次生壁的形成和纤维素合成等有着密切的联系,其中在纤维素合成过程中的作用尤为显著。本研究根据我们已获得的毛白杨PtSUS1基因片段设计引物,采用RACE技术,获得了毛白杨PtSUS1的基因序列,测序结果显示该基因序列全长为2 669 bp,包括一个完整的阅读框,编码805个氨基酸。通过Blast检索分析表明,PtSUS1与拟南芥、巨桉、陆地棉、温州蜜柑、毛果杨SUS1的核酸和氨基酸序列的同源性分别达到76%~97%和82%~97%。运用生物信息软件对PtSUS1编码的蛋白进行了二级结构预测和功能位点分析,结果显示该蛋白氨基酸序列包括两个功能域,存在可能的磷酸化位点38个,无跨膜结构域存在。系统进化分析表明PtSUS1与PtSUS2关系最为接近。RT-PCR分析结果显示,PtSUS1在被检测的毛白杨根、茎、叶及雌雄花芽组织和器官中均有表达,呈现组成型表达模式。该研究为进一步深入探索毛白杨蔗糖合酶基因PtSUS1的功能奠定了基础。
Sucrose synthase is closely related to plant regulon regulation, secondary wall formation and cellulose synthesis. Among them, sucrose synthase plays an important role in cellulose synthesis. In this study, based on the PtSUS1 gene fragment we have obtained, we designed the gene of PtSUS1 using RACE technique. The sequencing results showed that the full-length sequence of PtSUS1 gene was 2 669 bp, including a complete reading frame encoding 805 Amino acids. Blast search showed that the homologies between PtSUS1 and Arabidopsis thaliana, E. grandis, G. hystrix, S. sibiricum and S. poplar SUS1 were 76% -97% and 82% -97%, respectively. The bioinformatics software was used to predict the secondary structure of PtSUS1 protein and analyze its functional site. The results showed that the amino acid sequence of PtSUS1 contained two functional domains, and there were 38 possible phosphorylation sites without transmembrane domain. Phylogenetic analysis showed that PtSUS1 has the closest relationship with PtSUS2. The results of RT-PCR showed that PtSUS1 was expressed in the tissues, organs and tissues of the root, stem, leaf and male and female flower buds tested, showing the constitutive expression pattern. This study laid the foundation for further exploration of the function of PtSUS1 in Populus tomentosa sucrose synthase gene.