茶树己糖激酶基因CsHXK1的克隆与表达分析

Cloning and Expression Analysis of Hexokinase Gene CsHXK1 in Camellia sinensis

己糖激酶(HXK)是植物呼吸和代谢过程中的关键酶之一,不仅催化己糖磷酸化,而且参与植物糖感应和糖信号转导过程,在植物生长发育和逆境响应中发挥重要作用。试验以茶树‘龙井长叶’为材料,克隆获得了茶树己糖激酶基因CsHXK1的cDNA序列,其包含一个1488 bp的开放阅读框,编码495个氨基酸,预测蛋白分子质量为53.63 ku,理论等电点为5.96。蛋白序列分析结果显示,CsHXK1含有2个保守的磷酸化激酶域、1个底物结合域和1个ATP结合域,与拟南芥、苹果等HXK1亲缘关系较近。另外,CsHXK1基因启动子区域包含多种与逆境响应和糖信号转导相关的顺式作用元件,如ABA响应元件(ABRE)、脱水响应元件(MYBCORE)及糖信号转导相关元件(SREATMSD)等。qRT-PCR分析结果显示,CsHXK1基因表达受高温、干旱、低温及盐胁迫的诱导,其可能在茶树响应多种非生物胁迫过程中发挥重要作用。

Hexokinase(HXK)is one of the key enzymes in plant respiration and metabolism,which not only catalyzes hexosaccharide phosphorylation,but also participates in plant sugar induction and sugar signal transduction,and plays an important role in plant growth and development and stress response.In this study,‘Longjingchangye’tea plant was used as tested material,and the cDNA sequence of the CsHXK1 gene in tea plant was cloned,which including a 1488 bp open reading frame that encodes 495 amino acids with a molecular mass of 53.63 ku and a theoretical pI of 5.96.Protein sequence analysis showed that CsHXK1 contains two conserved phosphorylation kinase domains,one substrate binding domain and one ATP binding domain,and is closely related to HXK1 in Arabidopsis and apple.In addition,the promoter of CsHXK1 gene contains a variety of cis-acting elements related to stress response and sugar signal transduction,such as abscisic acid responsive element(ABRE),cis-acting element related to cold(MYBCORE)and sugar signal transduction related components,etc.The qRT-PCR analysis showed that the expression of CsHXK1 gene was induced by heat,drought,cold and salt stress,suggesting that it plays an important role in the response of tea plants to multiple abiotic stresses.