黄瓜逆境胁迫响应基因CsABI5的克隆与表达分析

Cloning and Expression Analysis of Cucumber Stress Response Gene CsABI5

脱落酸不敏感蛋白5(abscisic acid insensitive 5,ABI5)属于bZIP转录因子家族,广泛参与植物生长发育和逆境胁迫响应。本研究采用同源克隆的方法获得了黄瓜CsABI5基因,对其进行了生物信息学分析和组织特异性表达分析,并分析了其在盐胁迫和ABA处理下的表达情况。结果表明,CsABI5基因的CDS为1230 bp,编码409个氨基酸,其编码蛋白的分子量为44.88 kDa,理论等电点为9.53,亲水性平均系数为-0.603,属于亲水性碱性蛋白。多序列比对显示该蛋白与其他物种的ABI5蛋白具有较高的相似性,C端均含有典型的保守bZIP结构域。系统发育树显示葫芦科的ABI5聚为一支,CsABI5与甜瓜的CmABI5亲缘关系最近。实时荧光定量PCR(real-time quantitative PCR,RT-qPCR)测定发现,CsABI5在黄瓜营养器官和生殖器官中均有表达,在果刺中相对表达量最高。四叶期幼苗受100 mmol/L NaCl和100μmol/L ABA处理后CsABI5表达量显著上调,均在处理6 h升至最高。本研究结果可为抗逆黄瓜品种的选育提供参考。

Abscisic acid insensitive protein 5(ABI5)of the bZIP transcription factor family is widely involved in plant growth and development and response to adversity stress.In this paper,the cucumber CsABI5 gene was cloned by homologous cloning,and its bioinformatics characteristics,tissue expression pattern,and expression characteristics under salt stress and ABA treatments were analyzed.The results showed that the coding sequence(CDS)of CsABI5 was 1230 bp which encoded 409 amino acids.The predicted molecular weight and theoretical isoelectric point of CsABI5 protein were 44.88 kDa and 9.53,respectively,which was a hydrophilic basic protein with average hydrophilicity coefficient of-0.603.Multiple sequence comparison showed that CsABI5 had high similarity to ABI5 proteins of other species,which all contained a typical conserved bZIP domain at C-terminal.The phylogenetic tree showed that the ABI5 members of Cucurbitaceae were grouped into one clade,and CsABI5 was the most closely related to CmABI5 of melon.Real-time quantitative PCR(RT-qPCR)analysis showed that CsABI5 expressed in both nutritive and reproductive tissues of cucumber,and the highest relative expression level was found in fruit spines.The expression of CsABI5 was significantly up-regulated under the treatment of 100 mmol/L NaCl and 100μmol/L ABA,and both increased to the highest level at 6 h after treatment.These results could provide references for breeding of stress-resistant cucumber varieties.