《植物生理学报》 2016, 52(9): 1361-1370

苹果异分支酸合酶基因MdICS1的克隆与表达分析

马长青^1,3, 柏素花^2,3, 董超华², 张玉刚^1,3, 戴洪义^1,3,*

青岛农业大学¹园艺学院, ²生命科学学院, ³青岛市园艺植物遗传改良与育种重点实验室, 山东青岛266109

通信作者：戴洪义；E-mail: hydai@qau.edu.cn

摘　要：

异分支酸合酶(isochorismate synthase, ICS)是水杨酸合成途径中的关键酶, 在植物的防御反应中发挥重要作用。本实验以‘嘎拉’苹果(Malus ×domestica)的幼叶为试材克隆得到了ICS1基因, 命名为MdICS1 (GenBank登记号为KJ710067)。该基因开放阅读框(ORF)长度为1 683 bp, 编码560个氨基酸, 蛋白质的分子质量为62.172 9 kDa, 等电点(pI)为6.01。利用荧光定量PCR技术检测MdICS1基因在不同组织和器官中的表达量, 分析结果表明MdICS1在枝皮中的表达量最高, 在花瓣中的表达量最低。不同激素及胁迫处理的时序表达分析表明: 低温、NaCl、H₂O₂以及炭疽叶枯病菌(Glomerella cingulata)四种胁迫处理均能诱导MdICS1显著上调, 但在不同的逆境处理组上峰值的出现时间存在差异。MdICS1可以被茉莉酸(JA)、脱落酸(ABA)和乙烯(ETH)三种外源信号显著抑制, 而水杨酸(SA)可以诱导MdICS1的表达, 分析表明MdICS1在苹果植物抗逆境反应中发挥重要作用。

关键词：苹果; 异分支酸合酶; 基因克隆; 表达分析

收稿：2016-06-06   修定：2016-08-08

资助：国家现代农业产业技术体系建设专项资金(CARS-28-01-07)、国家自然科学基金(31471853)、山东省科技发展计划项目(2014GNC110017)、山东省良种产业化工程项目(620902)和“十二五”农村领域国家科技计划项目(2013BAD02B01)。

Identification and expression analysis of MdICS1 gene from apple (Malus ×domestica Borkh.)

MA Chang-Qing^1,3, BAI Su-Hua^2,3, DONG Chao-Hua², ZHANG Yu-Gang^1,3, DAI Hong-Yi^1,3,*

¹College of Horticulture, ²College of Life Sciences, ³Qingdao Key Laboratory of Genetic Improvement and Breeding in Horticultural Plants, Qingdao Agricultural University, Qingdao, Shandong 266109, China

Corresponding author: DAI Hong-Yi; E-mail: hydai@qau.edu.cn

Abstract:

Isochorismate synthase (ICS) is required for pathogen-induced biosynthesis of salicylic acid (SA), and plays an important role in plant defense responses. In the present study, an ICS1 gene was identified from leaves of ‘Gala’ apple (Malus ×domestica Borkh.) using rapid amplification of cDNA ends (RACE) technique (designated as MdICS1) in order to explore its role in protecting apple plant against biotic or abiotic stress. MdICS1 contains an opening reading frame (ORF) of 1 683 bp, which encodes a protein of 560 amino acid residues. The putative molecular weight of MdICS1 protein and isoelectric point (pI) are 62.172 9 kDa and 6.01, respectively. Quantitative real-time PCR revealed that the highest expression of MdICS1 mRNA was observed in bark, and the lowest was in flower. MdICS1 expression was significantly induced by low temperature of 4°C, NaCl and hydrogen peroxide (H₂O₂). Fungal pathogen of apple Glomerella cingulate can also significantly enhanced the expression of MdICS1. In addition, MdICS1 expression can be inhibited by phytohormones including ethylene (ETH), abscisic acid (ABA), and jasmonate (JA). However, MdICS1 expression was significantly increased by salicylic acid (SA). These results collectively suggest that MdICS1 may be involved in defense responses against biotic or abiotic stress mediated by SA.

Key words: apple; isochorismate synthase; gene cloning; expression analysis