《植物生理学报》 2015, 51(7): 1067-1074

精氨酸脱羧酶基因AtADC2通过调节超氧化物歧化酶和过氧化氢酶活性增强拟南芥耐盐性

郭彩明, 陈宗明, 陈春丽^*

华中农业大学生命科学技术学院, 武汉430070

通信作者：陈春丽；E-mail: chenchunli@mail.hzau.edu.cn；Tel: 027-87281300

摘　要：

腐胺(Put)在植物耐盐中有重要作用。精氨酸脱羧酶(ADC)是Put合成的关键限速酶, 该酶参与植物对盐胁迫响应的机制还不清楚。本文以拟南芥中编码ADC的基因AtADC2功能缺失突变体(adc2-3)和AtADC2超表达家系(ADC2-OE)为材料, 用NaCl模拟盐胁迫条件, 研究AtADC2对盐胁迫下拟南芥生长的影响机制。结果表明, 盐胁迫诱导AtADC2基因在拟南芥主根根尖表达上调。在150 mmol•L^-1 NaCl胁迫下, 与野生型相比, adc2-3生长受到严重抑制, 丙二醛(MDA)、超氧阴离子(O₂ ¯• )和过氧化氢(H₂O₂)含量均上升, 而AtADC2超表达家系中H₂O₂含量有所下降。另外, 盐处理后AtADC2超表达家系中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著升高, 而adc2-3中变化不明显。由此可见, 盐胁迫诱导AtADC2基因表达, 从而调节SOD和CAT活性来增强拟南芥的抗盐性。 关键词:

关键词：腐胺; 精氨酸脱羧酶; 盐胁迫; 超氧化物歧化酶; 过氧化氢酶

收稿：2015-05-08   修定：2015-07-09

资助：国家自然科学基金资助项目(J1103510)和中央高校基本科研业务费专项资金项目(2013PY084)。 致谢 英国杜伦大学生物学院Lindsey K.教授和Rowe J. H.博士修改英文。

AtADC2 Enhances Salt Tolerance through Regulating Activities of Superoxide Dismutase and Catalase in Arabidopsis thaliana

GUO Cai-Ming, CHEN Zong-Ming, CHEN Chun-Li^*

College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China

Corresponding author: CHEN Chun-Li; E-mail: chenchunli@mail.hzau.edu.cn; Tel: 027-87281300

Abstract:

Putrescine (Put) plays an important role in plant salt tolerance. Arginine decarboxylase (ADC) is a key rate-limiting enzyme in Put biosynthesis, but it remains unclear how ADC is involved in salt responses in plants. In this study, the loss-of-function mutant and the line overexpressing the AtADC2 gene encoding ADC were used to analysis how ADC affected the growth of Arabidopsis thaliana under the salt stress conditions. The results showed that salt treatment enhanced AtADC2 expression in the primary root tip. When grown in the presence of 150 mmol•L^-1 NaCl, the growth of the AtADC T-DNA insertion mutant line adc2-3 was inhibited more than wild type. The accumulation of malondialdehyde (MDA), superoxide anion (O₂ ¯• ) and hydrogen peroxide (H₂O₂) all increased in the mutant, but H₂O₂ decreased in the AtADC2 overexpression line. Enzyme activity assay showed that superoxide dismutase (SOD) and catalase (CAT) activities were significantly increased in AtADC2 overexpression line, but no change was detected in the adc2-3 mutant with salt treatment. These results indicate that the salt-stress-inducible AtADC2 gene may regulate SOD and CAT activities in response to salt stress.

Key words: putrescine; arginine decarboxylase; salt stress; superoxide dismutase; catalase