CAJ | 학술논문

为揭示9-顺式环氧类胡萝卜素双加氧酶(9-cis-epoxycarotenoid dioxygenase,NCED)在烟草生长发育过程中的功能，通过同源克隆方法获得烟草品种K326类胡萝卜素降解关键基因NCED3两个cDNA全长序列。序列分析表明：K326 NCED3-1和NCED3-2基因分别包含一个1842bp和1830bp的开放读码框(ORF),各编码613个和609个氨基酸。预测蛋白质分子量分别为68177.8 Da和67754.2Da，理论等电点(pI)各为7.66和7.28。跨膜区预测、亲水性和信号肽分析表明很可能是定位于线粒体膜上的亲水性跨膜蛋白。二级结构预测模型显示此蛋白结构以β折叠和无规则卷曲为主。蛋白三级结构预测分析表明NCED3-1与NCED3-2空间结构极为相似。PEG6000胁迫分析表明，干旱胁迫可以诱导NCED3基因表达以及内源ABA的积累。且在处理12h之前，NCED3表达与ABA累积速度均呈现升高趋势，之后逐渐降低。研究结果为解析NCED3在烟草抗旱方面的功能提供一定的研究基础。
위게시9-순식배양류호라복소쌍가양매(9-cis-epoxycarotenoid dioxygenase,NCED)재연초생장발육과정중적공능，통과동원극륭방법획득연초품충K326류호라복소강해관건기인NCED3량개cDNA전장서렬。서렬분석표명：K326 NCED3-1화NCED3-2기인분별포함일개1842bp화1830bp적개방독마광(ORF),각편마613개화609개안기산。예측단백질분자량분별위68177.8 Da화67754.2Da，이론등전점(pI)각위7.66화7.28。과막구예측、친수성화신호태분석표명흔가능시정위우선립체막상적친수성과막단백。이급결구예측모형현시차단백결구이β절첩화무규칙권곡위주。단백삼급결구예측분석표명NCED3-1여NCED3-2공간결구겁위상사。PEG6000협박분석표명，간한협박가이유도NCED3기인표체이급내원ABA적적루。차재처리12h지전，NCED3표체여ABA루적속도균정현승고추세，지후축점강저。연구결과위해석NCED3재연초항한방면적공능제공일정적연구기출。
In order to reveal the function ofNCED3 gene in tobacco plant growth and development, two copies (NCED3-1andNCED3-2) of full-length cDNA sequence of tobacco nine-cis-epoxycarotenoid dioxygenase3 were cloned from K326 by homology cloning strategy. Sequences analysis showed thatNCED3-1and NCED3-2 contained 1842-bp and 1830-bp open reading frame (ORF ) and coded 613 and 609 amino acid residues, and the calculated molecular mass was 68177.8Da and 67754.2Da with the theoretical isoelectric point (pI) of 7.22 and 7.28, respectively. Protein hydrophobicity, transmembrane domains and signal peptide analysis indicated that the protein might be transmembrne and hydrophilic, and located on mitochondrial membrane. Secondary structure prediction results showed that they were mainly made up by beta turns and random coil. Tertiary structure prediction results displayed that NCED3-1 showed high similarity with NCED3-2. Expression patterns under abiotic stress responses suggested that PEG6000 could induce expression ofNCED3 and accumulation of ABA. Expression of NCED3 and ABA accumulation rate both increased before 12h treatment, and then decreased gradually. These results provided some basis for drought function analysis ofNCED3.