《植物生理学报》 2013, 49(2): 181-187

G蛋白位于H₂O₂上游参与H₂S诱导的拟南芥气孔关闭过程

张丹丹, 车永梅, 侯丽霞, 赵方贵, 刘新*

山东省高校植物生物技术重点实验室, 青岛农业大学生命科学学院, 山东青岛266109

通信作者：刘新；E-mail: liuxin6080@yahoo.com.cn；Tel: 0532-88030224

摘　要：

硫化氢(H2S)可诱导拟南芥气孔关闭。本文以拟南芥野生型及其G蛋白α亚基缺失突变体(Atgpa1-3、Atgpa1-4)和β亚基缺失突变体(Atagb1-1、Atagb1-2)为材料, 研究了G蛋白在H2S诱导拟南芥气孔关闭中的作用及其与H2O2的关系。结果表明, H2S可诱导野生型拟南芥气孔关闭及G蛋白α亚基(GPA)和β亚基(AGB)基因表达量增加, 但对Atgpa1-3、Atgpa1-4、Atagb1-1和Atagb1-2叶片气孔运动无显著影响; G蛋白激活剂霍乱毒素(CTX)增强H2S诱导拟南芥气孔关闭的作用, 而其抑制剂百日咳毒素(PTX)能够阻断H2S的诱导作用, 表明G蛋白参与H2S诱导的拟南芥气孔关闭过程。同时, H2S诱导野生型拟南芥叶片及气孔保卫细胞H2O2含量升高, 但对Atgpa1-3、Atgpa1-4、Atagb1-1和Atagb1-2无显著作用。CTX促进拟南芥叶片及气孔保卫细胞中H2O2积累, 而PTX抑制H2S引起的拟南芥叶片及气孔保卫细胞中H2O2含量的升高。由此说明, G蛋白位于H2O2上游参与H2S诱导的拟南芥气孔关闭过程。

关键词：G蛋白; 硫化氢; 过氧化氢; 气孔关闭

收稿：2012-12-06   修定：2013-01-22

资助：国家自然科学基金(30970228和31170237)、山东省自然科学基金(ZR2010CM024)和植物生理学与生物化学国家重点实验室开放课题(SKLPPBKF11001)。

G-Protein Acts Upstream of H₂O₂ in Mediating H2S-Induced Stomatal Closure in Arabidopsis thaliana

ZHANG Dan-Dan, CHE Yong-Mei, HOU Li-Xia, ZHAO Fang-Gui, LIU Xin*

Key Lab of Plant Biotechnology in Universities of Shandong Province, College of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China

Corresponding author: LIU Xin; E-mail: liuxin6080@yahoo.com.cn; Tel: 0532-88030224

Abstract:

Hydrogen sulfide (H2S) induces stomatal closure in Arabidopsis thaliana, hydrogen peroxide (H₂O₂) plays an important part in this procedure. In this paper, Arabidopsis wide type and its α subunit deficient mu-tants (Atgpa1-3 and Atgpa1-4) as well as β subunit deficient mutants (Atagb1-1 and Atagb1-2) were used as materials, the effects of G-protein on H2S-induced stomatal closure and the relationship between G-protein and H₂O₂ were investigated. The results showed that H2S induced stomatal closure as well as the expression of G-protein α subunit (GPA) and β subunit (AGB) gens in leaves of Arabidopsis wild type, but had no significant ef-fects on stomatal movement in Atgpa1-3, Atgpa1-4, Atagb1-1 and Atagb1-2 mutants. GPA activator cholera toxin (CTX) improved H2S-induced stomatal closure, but its inhibitors pertussis toxin (PTX) showed the oppo-site effect. These results manifested that G-protein was an signaling intermediate in H2S-induced stomatal clo-sure. H2S induced increase in H₂O₂ content in leaves and guard cells of A. thaliana wide type, but not in Atg-pa1-3, Atgpa1-4, Atagb1-1 and Atagb1-2 mutants. CTX enhanced H₂O₂ content in leaves and guard cells of Arabidopsis, but its inhibitor PTX was opposite. From these data it could be deduced that G-protein acts up-stream of H₂O₂ in mediating H2S-induce stomatal closure in Arabidopsis.

Key words: G-protein; hydrogen sulfide; hydrogen peroxide; stomatal closure