《植物生理学报》 2018, 54(8): 1325-1332

γ-氨基丁酸代谢影响拟南芥叶片节律性运动

陈意¹, 岳涵², 向宇³, 余光辉^1,2,3,*

¹中南民族大学生命科学学院, 中国莼菜研究所, 武汉430074; ²中南民族大学生命科学学院, 武陵山区特色资源植物种质保护与利用湖北省重点实验室, 武汉430074; ³中南民族大学生命科学学院, 南方少数民族地区资源保护综合利用联合工程中心, 武汉430074

通信作者：余光辉；E-mail: yusheen@163.com

摘　要：

为阐明γ-氨基丁酸(γ-aminobutyric acid, GABA)和生物节律调控的关系, 本文以GABA合成(谷氨酸脱羧酶gad等)和代谢(GABA转氨酶GABA-T/pop2、谷氨酸脱氢酶gdh等)突变体, 以拟南芥叶片节律性运动为监测指标, 探讨了GABA代谢与叶片节律性运动的关系。结果显示, GABA合成突变体(gad1-3)和双突变体gad1/gad2中叶片节律性运动的振幅低于野生型, 在gad1、gad2和gad1/gad2中叶片运动的振幅变化明显; pop2突变体中, 叶片运动的节律性变化的振幅明显低于对照, gdh1/gdh2突变体中, 叶片运动呈现非节律性变化的特点; 此外, 外源γ-氨基丁酸(1.0 mmol·L^-1)不同程度提高拟南芥3种生态型(Col、Ler、Ws)叶片节律性运动的振幅, 其中Col生态型和Ws生态型叶片振幅变化明显; 在生物钟核心基因突变体toc1、lhy、cca1中, 叶片运动呈现非节律性变化模式; 但外源GABA的添加能够提高这些突变体叶片节律性运动的振幅或者恢复叶片的节律性。上述结果表明GABA代谢平衡直接和间接影响生物钟节律, 外源或内源GABA的合成或代谢突变主要影响到叶片节律性运动的振幅。

关键词：γ-氨基丁酸; 生物节律; 叶片运动; GABA代谢; 拟南芥

收稿：2018-03-08   修定：2018-07-27

资助：国家自然科学基金(31270361)。

Effects of γ-aminobutyric acid metabolism on leaf rhythmic movement in Arabidopsis thaliana

CHEN Yi¹, YUE Han², XIANG Yu³, YU Guang-Hui^1,2,3,*

¹China Brasenia schreberi Research Institute, College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China; ²Hubei provincial Key laboratory for protection and application of special plants in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China; ³Engineering Research Centre for the Protection and Utilization of Bioresource in Ethnic Area of Southern China, College of Life Sciences, South-Central University for Nationalities, Wuhan 430074, China

Corresponding author: YU Guang-Hui; E-mail: yusheen@163.com

Abstract:

To elucidate the relationship between γ-aminobutyric acid (GABA) and circadian clock regulation, using rhythmic movement of Arabidopsis leaf as monitoring indicators, the mutants of GABA biosynthesis enzymes (glutamic acid decarboxylase, GAD) and catabolism enzymes (GABA transaminase, GABA-T/POP2 and glutamate dehydrogenase, GDH, etc.) were employed to explore the inherent interaction of GABA metabolism and biological rhythm. The results showed that in GABA biosynthetic mutant (gad1-3) and double mutant gad1/gad2, the amplitude of rhythmic movement of leaves was lower than that of wild type in different degrees, and the amplitude of leaf movement varied significantly in gad1, gad2 and gad1/gad2. In pop2 mutant, the amplitude of rhythmic change of leaf movement was significantly lower than that of control. In gdh1/gdh2 mutant, leaf movement showed arrhythmic pattern. Furthermore, exogenous GABA (1.0 mmol·L^-1) could increase the amplitude of the rhythmic movement of the leaves in three ecotypes of Arabidopsis thaliana (Col, Ler, Ws) to different extent, and the amplitude had obvious changes in Col ecotype and Ws ecotype after GABA spraying. In toc1, lhy and cca1 mutants, leaf movement showed arrhythmic change pattern, but exogenous GABA addition could increase the amplitude of rhythmic movement of these mutants or restore to the rhythmic movement of leaves. This results fully indicate that there is a direct or indirect governing relationship between the GABA metabolism and the circadian clock. These results also indicate that the balance of intracellular GABA metabolism has direct and indirect effect on circadian rhythm. Data herein show that exogenous GABA and its endogenous biosynthetic/metabolic mutants mainly affect the amplitude of leaf rhythmic movement.

Key words: γ-aminobutyric acid; circadian rhythm; leaf movement; GABA metabolism; Arabidopsis thaliana