《植物生理学报》 2018, 54(3): 456-464

AtWRKY40参与拟南芥干旱胁迫响应过程

车永梅^#, 孙艳君^#, 卢松冲, 赵方贵, 侯丽霞, 刘新^*

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

通信作者：刘；E-mail: liuxin6080@126.com

摘　要：

以拟南芥(Arabidopsis thaliana)野生型、AtWRKY40缺失突变体和过表达株系为材料, 研究AtWRKY40在植物干旱胁迫响应过程中的作用及其生理和分子机制。结果显示, AtWRKY40受干旱胁迫诱导; AtWRKY40缺失导致干旱胁迫下种子萌发率降低, 叶片失水加剧, 而AtWRKY40过表达植株呈现出相反的表征; 干旱胁迫下, AtWRKY40缺失突变体植株叶片过氧化氢(H₂O₂)、超氧阴离子(O₂ ^¯· )及丙二醛(MDA)含量显著高于野生型及其过表达株系, 超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性、脯氨酸(Pro)和可溶性糖含量以及相关基因AtCu/ZnSOD、AtCAT1、AtP5C1S、AtG6PD5和AtBAM4表达量显著低于野生型, 同时AtWRKY40过表达株系的渗透物质含量和保护酶活性及其基因表达量则高于野生型。由此说明, AtWRKY40通过调节植株抗氧化能力及渗透调节能力参与拟南芥干旱胁迫响应过程。

关键词：AtWRKY40; 干旱; 渗透调节物质; 保护酶; 拟南芥

收稿：2017-10-23   修定：2018-01-24

资助：国家自然科学基金(31572107和31770275)。

AtWRKY40 functions in drought stress response in Arabidopsis thaliana

CHE Yong-Mei^#, SUN Yan-Jun^#, LU Song-Chong, ZHAO Fang-Gui, HOU Li-Xia, LIU Xin^*

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

Corresponding author: LIU Xin; E-mail: liuxin6080@126.com

Abstract:

WRKY transcription factors are involved in diversely biotic and abiotic stresses in plants. In the current study, we investigated the role of AtWRKY40 in plant drought stress responses using wild type and transgenic Arabidopsis thaliana plants. Under drought stress, the expression of AtWRKY40 was strongly induced in the wild-type plants. Loss-of-function mutants had seed germination rate decreased and leaf water loss rate increased under drought, while the trends were opposite in the overexpression lines. In addition, Atwrky40 mutant plants accumulated more malondialdehyde (MDA) than the wild type and overexpression lines, indicating elevated lipid peroxidation in the mutants. To further elucidate the underlying mechanisms, we measured the activities of two reactive oxygen species (ROS)-scavenging enzymes, osmolyte accumulation, as well as the relative expression levels of relevant genes under drought stress. In the mutant lines, the activities of superoxide dismutase (SOD) and catalase (CAT) as well as the contents of proline and water-soluble sugars were all lower than those in the wild type plants. In consistent, the expression levels of Cu/ZnSOD, CAT1, Δ′-pyrroline-5-carboxylate synthetase 1 (P5CS1), glucose-6-phosphate dehydrogenase 5 (G6PDH5) and β-amylase 4 (BAM4) were significantly lower in the mutant lines compared to the wild type plants. Again, we observed an opposite trend of regulation by drought stress of these enzymes, osmolytes, and genes in the overexpression lines. Putting together, our results strongly suggest a positive role of AtWRKY40 in plant drought stress responses, presumably by interfering with the ROS-scavenging pathway and osmolyte accumulation process.

Key words: AtWRKY40; drought; osmotic substance; antioxidant enzyme; Arabidopsis thaliana