苹果阳离子氨基酸转运蛋白(CAT)的鉴定、比较与表达分析

Identification, comparison and expression analysis of cationic amino acid transporter(CAT) in apple

阳离子氨基酸转运蛋白(CAT)在植物氨基酸转运与氮素代谢中具有重要作用,重要经济作物苹果中尚未见此类蛋白的相关报道。本文利用生物信息学和分子生物学的方法,对苹果CAT (命名为MdCAT)成员进行鉴定、比较与表达分析。根据拟南芥CAT蛋白序列,在苹果基因组中共鉴定出15个MdCAT成员,它们不均衡地位于8条染色体上。大多数MdCAT具有10个及以上的跨膜区,并具有相似的二级结构组成和三维空间构象。遗传进化树分析表明, MdCAT蛋白分为4组(I、II、III和IV),并且4组成员在保守基序分布上,表现出各自的独特性。电子表达谱分析显示, MdCAT广泛表达于各组织中,尤其在花和果实等表达较高,不同成员稍有差异。在果实发育中, MdCAT3/7/6/14等转录丰度有明显的增加,在果实的氨基酸转运中可能扮演关键角色;休眠芽的表达数据提示,部分MdCAT参与到苹果芽的休眠过程。除此之外,利用实时荧光定量PCR试验,检测了氮素匮乏状态下MdCAT的相对表达,结果表明MdCAT1/6/10/13响应氮饥饿,可能在氮素代谢中发挥重要作用。

Cationic amino acid transporters(CAT) play important role in amino acid transport and nitrogen metabolism in plants, such proteins have not been reported in apple, which is an important economic crop. In this paper, the methods of bioinformatics and molecular biology were used to identify, compare and analyze the expression of apple CAT(named MdCAT) members. According to Arabidopsis CAT protein sequences, a total of 15 MdCAT members were identified in the apple genome. They’re not evenly distributed on eight chromosomes. Most MdCAT has 10 or more transmembrane regions, and they have similar secondary structure composition and three-dimensional conformation. Genetic evolutionary tree analysis showed that MdCAT proteins are divided into four groups(I, II, III and IV), and four group members on the conservative motif distribution, show their uniqueness. Electron expression spectrum analysis showed that MdCATs are widely expressed in various tissues, especially in flowers and fruits. There are slight differences among different members. During fruit development, the transcription abundance of Md CAT3/7/6/14 is significantly increased, which may play a key role in the transport of amino acids in fruits. The expression data of dormant buds suggested that part of MdCATs are involved in the dormancy process of apple buds. In addition, the relative expression of MdCAT in the nitrogen deficient state was detected by real-time fluorescence quantitative PCR test, and the results showed that MdCAT1/6/10/13 responds to nitrogen starvation, may play an important role in nitrogen metabolism.