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本研究利用RACE技术,从“昭锦”栽培种苹果中克隆得到一个长度为1275bp的cDNA序列,包含一个完整开放阅读框,编码255个氨基酸。与GenBank中MdNAC22基因同源,命名为MdNAC。生物信息学分析表明:非编码区包含1个BOX4、2个CAAT-BOX、4个TATA-BOX、1个CCAAT-BOX、1个Skn-1motif和1个ARE,不具有miR164靶序列。相对分子质量为28.87kD,为碱性亲水性蛋白,具有NAC蛋白典型的结构域,无核定位信号和跨膜结构,蛋白质二级结构主要以β-折叠和β-转角为主,三级结构与OsNAC1蛋白类似,但其结构需要进一步优化。系统发育树分析与植物分类学结论大致相符。MdNAC基因定位于16号染色体上。基因芯片表达谱分析表明MdNAC在高温、高盐、低温、外源ABA下都能被显著诱导。这些为进一步进行其功能分析及转基因研究工作奠定了理论基础。
In this study, a 1275bp cDNA sequence was cloned from cultivars of apple “Zhaogu” using RACE technique, and contained a complete open reading frame (ORF) encoding 255 amino acids. It is homologous to MdNAC22 gene in GenBank and named as MdNAC. Bioinformatics analysis showed that the non-coding region contains one BOX4, two CAAT-BOXs, four TATA-BOXs, one CCAAT-BOX, one Skn-1 motif and one ARE, and does not have the miR164 target sequence. The relative molecular mass is 28.87 kD, which is a basic hydrophilic protein. It has the typical domain of NAC protein, nuclear localization signal and transmembrane structure. The secondary structure of protein is mainly β-sheet and β-turn, Its structure is similar to that of OsNAC1, but its structure needs to be further optimized. Phylogenetic tree analysis roughly agrees with plant taxonomy. MdNAC gene is located on chromosome 16. Gene chip profiling showed that MdNAC was significantly induced by high temperature, high salt, low temperature and exogenous ABA. These laid the theoretical foundation for further functional analysis and transgenic research.