甘蔗蔗糖转运蛋白SoSUT2基因克隆和表达分析

为分析甘蔗SUT家族基因新成员的序列特征和基因表达模式,采用cDNA末端快速克隆技术,以甘蔗GT28未成熟茎cDNA为模板克隆蔗糖转运蛋白基因,命名为SoSUT2-h1,GenBank登录号KF808330。该基因的cDNA序列全长为2 132bp,开放阅读框长1 749bp,编码582个氨基酸,预测分子量和等电点分别为61.80ku和6.17。SoSUT2-h1蛋白具有12个跨膜结构。该蛋白具有保守的蔗糖转运蛋白功能域,属于MFS蛋白家族和GPH(蔗糖/H+共转运体)超家族中的一员。荧光定量PCR表明在甘蔗叶、花序、芽、茎和根中都能检测到SoSUT2基因表达,其中在芽中表达量最高,花序次之,而在根中表达量最低。在甘蔗工艺成熟期,SoSUT2基因表达量与节间蔗糖含量呈正相关性,推测该基因可能参与调控甘蔗节间蔗糖的积累。

Cloning and expression analysis of sucrose transporter gene (SoSUT2) in sugarcane

The objective of this study is to clone the sucrose transporter gene (SUT) from sugarcane and to analyze its sequence and expression patterns.Rapid amplification of cDNA ends was used to clone gene for SUTgene from the sugarcane immature internodes,which was named as SoSUT2-h1 gene with the GenBank accession number KF808330.The full-length cDNA of SoSUT2-h1 was 2 132 bp,containing a 1 749 bp open reading frame (ORF) which encodes 582 amino acids with a theoretical molecular mass of 61.80 ku and isoelectric point of 6.17.The So SUT2-h1 protein was predicted to exhibit typical features of sucrose transporters with 12 trans-membrane spanning domains,belonging to a member of major facilitator superfamily and GPH family sucrose/H⁺ symporter.The results of quantitative real-time PCR (qRT-PCR) showed that the expression of SoSUT2 could be detected in roots,stalks,leaves,flowers and buds,among which the highest was found in buds,followed by flowers,and the lowest was in roots at the physiological maturing stage of sugarcane.In internode of sugarcane,the sucrose content was positively correlated with the SoSUT2 gene expression quantities at maturing stage.The gene expression pattern indicated SoSUT2 might be the key enzymes involved in regulating sucrose accumulation during the growth and development of the internodes of sugarcane stalks.