椰子NCED2基因克隆及逆境响应表达分析

Cloning and Abiotic Stress-induced Expression of NCED2 Gene of Coconut(Cocos nucifera L.)

顺式-环氧类胡萝卜素双氧合酶(9-cis-epoxy carotenoids dioxygenase, NCED)是ABA生物合成间接途径的关键限速酶,在植物逆境响应中有重要作用。本研究利用RT-PCR从‘文椰2号’椰子中鉴定出NCED2基因。结果表明,CnNCED2基因长度为1 845 bp,编码614个氨基酸。其蛋白主要由α-螺旋、无规则卷曲、β-转角和延伸连构成,为亲水蛋白。在CnNCED2的启动子序列上发现了TC重复序列、MBS、LTR等与逆境密切相关的顺式作用元件,以及CGTCA模序、TGA元件、TGACG模序、ABRE等与植物激素相关的顺式作用元件。基因表达分析发现CnNCED2受低温和干旱胁迫诱导,分别在低温处理后12 h和干旱处理后6 h达到峰值,而盐胁迫处理抑制NCED2的表达。本研究分析了CnNCED2在3种逆境胁迫下的表达特征,对椰子抗性育种有一定参考作用。

NCED is a key rate-limiting enzyme in the indirect pathway of ABA biosynthesis and plays an important role in plant stress response. In this study, RT-PCR was used to identify the NCED2 gene from the ’Wenye2’ coconut. The results showed that the full length sequence of CnNCED2 was 1 845 bp, encoding 614 amino acids. CnNCED2 was a hydrophilic protein, and the secondary structure was mainly composed of alpha helix, random coils, β-turn and extension links. Cis-acting elements closely related to abiotic stress(such as TC-rich repeats, MBS and LTR) and plant hormones response(CGTCA-motif, TGA-element, TGACG-motif, and ABRE) were founded in promotor of CnNCED2. CnNCED2 gene was induced by low temperature and drought stress. The expression level of CnNCED2 reached peak at 12 h after low temperature treatment and 6 h after drought treatment, respectively.While salt stress inhibited the expression of CnNCED2. In this study, the expression characteristics of CnNCED2 under three kinds of stress were analyzed, which provide a theoretical basic for coconut resistance breeding.