藜麦CqSAP8基因克隆及其在非生物胁迫下的表达分析

该研究根据NCBI公布的藜麦胁迫相关蛋白(SAP)基因CqSAP8序列进行克隆，利用生物信息学分析CqSAP8蛋白序列、理化性质和结构特点，并采用qRT PCR方法检测CqSAP8基因表达的组织特异性及在非生物胁迫下的相对表达。结果表明：(1)藜麦CqSAP8基因CDS全长528 bp，编码175个氨基酸；预测CqSAP8蛋白分子量为18.73 kD，理论等电点为7.46，属于稳定的亲水性蛋白质；CqSAP8蛋白在N端和C端分别含有A20和AN1保守域，是SAP蛋白最典型的类型。(2)序列比对与进化分析显示，藜麦CqSAP8与甜菜BvSAP8、菠菜SoSAP8亲缘关系最近，序列相似性分别为89.66%和89.47%。(3)qRT PCR分析表明，藜麦CqSAP8基因在根、茎、叶、花和种子中均有表达，且在种子中表达量最高；CqSAP8基因在干旱和高温胁迫12 h表达量达到最大值，分别是对照的13.09和17.47倍，高盐和低温胁迫下的最大表达量均为对照的3.91倍，说明藜麦CqSAP8基因响应多种非生物胁迫应答；另外，藜麦CqSAP8的表达量在ABA胁迫下24 h急剧升高，推测CqSAP8基因在非生物胁迫前期的响应不依赖ABA。该研究为进一步研究CqSAP8基因功能及抗逆分子机制奠定了基础。

Cloning and Expression Analysis of CqSAP8 in Chenopodium quinoa under Abiotic Stresses

In this study, Chenopodium quinoa CqSAP8 was cloned based on the sequence on the NCBI website. Bioinformatics methods were used to analyze the sequence, physicochemical property and structure of CqSAP8 protein. The expression patterns of CqSAP8 in tissues and under different abiotic stresses were determined by using qRT PCR method. The results showed that: (1) the CDS of CqSAP8 was 528 bp, encoding 175 amino acids with a relative molecular weight of 18.73 kD and an isoelectric point of 7.46. CqSAP8 was predicated to be a stable hydrophilic protein. CqSAP8 contained a A20 conserved domain in the N terminus and an AN1 conserved domain in the C terminus, which was a typical SAP protein. (2) Sequence alignment and evolutionary analysis showed that CqSAP8 was mostly closely related to BvSAP8 and SoSAP8 with a sequence similarity 89.66% and 89.47%, respectively. (3) qRT PCR analysis showed that CqSAP8 expressed in root, stem, leaf, flower and seed, and the highest expression was found in seed. The expression of CqSAP8 gene reached the maximum at 12 h under drought stress and high temperature stress, which was 13.09 and 17.47 times of that of the control, respectively, while the maximum expression under both high salt and low temperature stress was 3.91 times that of the control, indicating that CqSAP8 responded to a variety of abiotic stresses. Additionally, The expression level of CqSAP8 increased sharply at 24 h under ABA stress, suggesting that the response of CqSAP8 in the early stage of abiotic stress was independent of ABA. This study laid a foundation for further study on the function and molecular mechanism of CqSAP8 gene.