摘要：

钙调蛋白是植物体内一种重要的Ca²⁺受体蛋白,在钙信号途径及抗逆反应中发挥着重要作用。为研究番茄CaM蛋白在低温胁迫下的作用机制,以番茄品种Heinz1706、LA3969、冀粉2号、冀粉3号和农博粉霸15为材料,克隆得到了番茄钙调蛋白基因SlCaM3、SlCaM4和SlCaM5,并进行序列分析和启动子区顺式作用元件分析;利用qRT-PCR技术分析SlCaM3、SlCaM4和SlCaM5在不同番茄品种中15,5 ℃低温胁迫下的表达模式,并结合RNA-seq数据分析组织特异性表达情况。结果显示,SlCaM3、SlCaM4和SlCaM5的CDS序列均为450 bp,三者相似度为93.63%;所编码的氨基酸序列完全相同,属酸性稳定亲水蛋白,具有典型的CaM蛋白保守结构域。启动子顺式作用元件分析表明,3个基因的启动子区除含有必需的核心元件外,还含有多种生物及非生物胁迫响应元件,并呈现互补模式分布。不同程度低温胁迫表达模式分析表明,15 ℃胁迫下,SlCaM3、SlCaM4和SlCaM5基因在5种番茄材料中的表达模式均呈现出先降低后升高的趋势,其中SlCaM5基因的表达量升高更为显著;5 ℃胁迫下,SlCaM3、SlCaM4基因的表达水平变化不明显,而SlCaM5基因在处理后期表达量显著升高;表明SlCaM5在低温下维持着CaM蛋白的翻译水平。SlCaM3、SlCaM4和SlCaM5基因在Heinz1706不同组织中的特异性表达情况显示,SlCaM3和SlCaM4在分生组织中具有较高的表达,而SlCaM5基因在不同组织中表达水平差异不明显。

关键词: 番茄, 钙调蛋白, 低温, 基因克隆, qRT-PCR, 表达分析

Abstract:

Calmodulin is an important Ca²⁺ receptor protein in plants,which plays an important role in calcium signaling pathway and stress resistance.It is of great significance to study the mechanism of CaM protein in tomato under low temperature stress for cold tolerance breeding of tomato.Tomato calmodulin genes SlCaM3, SlCaM4 and SlCaM5 were cloned from tomato varieties Heinz1706,LA3969,Jifen 2,Jifen 3 and Nongbofenba 15,and their sequences and protein sequences were analyzed by bioinformatics;the cis acting elements in the promoter regions of SlCaM3,SlCaM4 and SlCaM5 were analyzed by plantcare;Quantitative Real-time PCR was used to analyze the expression patterns of SlCaM3,SlCaM4 and SlCaM5 under 15,5 ℃ temperature stress in different tomato varieties,and the specific expression of SlCaM3,SlCaM4 and SlCaM5 in different tissues was analyzed in combination with RNA-seq data.The results showed that the coding sequence of SlCaM3,SlCaM4 and SlCaM5 were 450 bp,and their similarity was 93.63%;the encoded amino acid sequences were identical,belonging to acidic stable hydrophilic protein with typical conservative domain of cam protein.The analysis of cis acting elements showed that the promoter regions of the three genes contained not only the necessary core elements,but also a variety of biotic and abiotic stress response elements,and showed a complementary pattern.The analysis of the expression patterns of different degrees of low temperature stress showed that the expression patterns of SlCaM3,SlCaM4 and SlCaM5 in five tomato materials showed a trend of first decreasing and then increasing at 15 ℃,and the expression of SlCaM5 increased more significantly.At 5 ℃,SlCaM3 and SlCaM4 did not change significantly,but the expression level of SlCaM5 gene increased significantly in the later stage of treatment.The high expression of SlCaM5 gene in the process of tomato resistance to low temperature indicated that it maintained the translation level of cam protein under low temperature and ensured that the function of CaM protein was not affected.The analysis of SlCaM3,SlCaM4 and SlCaM5 specific expression in different tissues of Heinz1706 showed that SlCaM3 and SlCaM4 were highly expressed in meristem,while the expression of SlCaM5 different tissues was not significantly different.

Key words: Tomato, Calmodulin, Cold, Gene cloning, qRT-PCR, Expression analysis