《植物生理学报》 2017, 53(3): 413-421

胡萝卜S-腺苷甲硫氨酸脱羧酶SAMDC基因的克隆及其对非生物胁迫的响应

王广龙^1,2,*, 却枫², 陈伯清¹, 任旭琴¹, 王纪忠¹, 熊爱生^2,*

¹淮阴工学院生命科学与食品工程学院, 江苏淮安223003; ²南京农业大学园艺学院, 作物遗传与种质创新国家重点实验室, 农业部华东地区园艺作物生物学与种质创制重点实验室, 南京210095

通信作者：王广龙；E-mail: wanggl89@hyit.edu.cn; xiongaisheng@njau.edu.cn

摘　要：

S-腺苷甲硫氨酸脱羧酶是多胺生物合成过程中的关键酶, 对于植物生长发育和抵御逆境胁迫等过程具有重要作用。本研究利用RT-PCR方法从胡萝卜品种‘黑田五寸’中克隆得到一个编码S-腺苷甲硫氨酸脱羧酶的基因DcSAMDC。序列分析显示, 该基因包含一个全长1 086 bp的开放阅读框, 编码361个氨基酸。预测其蛋白质相对分子质量为40.16 kDa, 理论等电点为4.89。胡萝卜S-腺苷甲硫氨酸脱羧酶具有高度保守的酶原剪切位点和PEST结构域。进化分析表明, 胡萝卜SAMDC与葡萄的进化关系最为接近。荧光定量PCR分析显示, 胡萝卜DcSAMDC基因在叶片和根中的表达水平较高, 对高温(38ºC)、低温(4ºC)、模拟干旱(200 g·L^-1 PEG)和盐渍(200 g·L^-1 NaCl)胁迫有响应, 并且, 响应的时间较为迅速, 在胁迫1~4 h后表达水平升至最高。本研究结果表明, DcSAMDC基因可能在胡萝卜抵御非生物胁迫的过程中发挥重要作用。

关键词：S-腺苷甲硫氨酸脱羧酶; 克隆; 序列分析; 非生物胁迫; 表达分析; 胡萝卜

收稿：2016-09-23   修定：2017-01-20

资助：淮阴工学院博士科研启动基金(Z301B16531)、教育部新世纪优秀人才支持计划项目(NCET-11-0670)和江苏省自然科学基金杰出青年基金(BK20130027)。

Cloning of S-adenosylmethioine decarboxylase gene SAMDC from Daucus carota and its response to abiotic stresses

WANG Guang-Long^1,2,*, QUE Feng², CHEN Bo-Qing¹, REN Xu-Qin¹, WANG Ji-Zhong¹, XIONG Ai-Sheng^2,*

¹School of Life Science and Food Engineering, Huaiyin Institute of Technology, Huaian 223003, China; ²State Key Laboratory of Crop Genetics and Germplasm Enhancement, Ministry of Agriculture Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China

Corresponding author: WANG Guang-Long; E-mail: wanggl89@hyit.edu.cn; xiongaisheng@njau.edu.cn

Abstract:

S-adenosylmethioine decarboxylase (SAMDC), a key enzyme involved in polyamine biosynthesis, plays important roles in plant development and resistance against adverse circumstances. In this study, a gene DcSAMDC that encodes S-adenosylmethioine decarboxylase was cloned from carrot cultivar ‘Kurodagosun’ using RT-PCR. Sequence analysis indicated that the DcSAMDC gene harbored an open reading frame of 1 086 bp encoding 361 amino acids. The relative molecular mass of its protein was predicted to be 40.16 kDa with a theoretical isoelectric point of 4.89. DcSAMDC possesses highly conserved function domains, proenzyme cleavage site and PEST domain. The evolutionary relationship of DcSAMDC was more close to grape (Vitis vinifera). Quantitative real-time PCR analysis indicated that carrot DcSAMDC gene was highly expressed in the leaves and roots. Moreover, this gene can respond to high temperature (38ºC), low temperature (4ºC), PEG-induced drought (200 g·L^-1 PEG), and salinity (200 g·L^-1 NaCl), and its expression levels were highest from 1 to 4 h after treatment. The results suggested that DcSAMDC gene may play important roles in carrot plant tolerance to abiotic stresses.

Key words: S-adenosylmethioine decarboxylase; clone; sequence analysis; abiotic stress; expression analysis; Daucus carota