title: Copper suppresses abscisic acid catabolism and catalase activity, and inhibits seed germination of rice.
abstract: Although copper (Cu) is an essential micronutrient for plants, a slight excess of Cu in soil can be harmful to plants. Unfortunately, Cu contamination is a growing problem all over the world due to human activities, and poses a soil stress to plant development. As one of the most important biological processes, seed germination is sensitive to Cu stress. However, little is known about the mechanism of Cu-induced inhibition of seed germination. In the present study, we investigated the relationship between Cu and ABA which is the predominant regulator of seed germination. Cu at a concentration of 30 µM effectively inhibited germination of rice caryopsis. ABA content in germinating seeds under copper stress was also higher than that under control conditions. Quantitative real-time PCR (qRT-PCR) revealed that Cu treatment reduced the expression of OsABA8ox2, a key gene of ABA catabolism in rice seeds. In addition, both malondialdehyde (MDA) and H2O2 contents were increased by Cu stress in the germinating seeds. Antioxidant enzyme assays revealed that only catalase activity was reduced by excess Cu, which was consistent with the mRNA profile of OsCATa during seed germination under Cu stress. Together, our results demonstrate that suppression of ABA catabolism and catalase (CAT) activity by excess Cu leads to the inhibition of seed germination of rice.
authors.affiliation: Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
authors.forename: Nenghui
authors.initials: N
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, China.
authors.forename: Haoxuan
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Life Science, South China Agricultural University, Guangdong, China.
authors.forename: Guohui
authors.initials: G
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, China.
authors.forename: Yinggao
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Life Science, Shandong University, Taian, Shandong, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Jing
authors.affiliation: College of Life Science, South China Agricultural University, Guangdong, China.
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Peng
authors.affiliation: Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, China jhzhang@cuhk.edu.hk.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D002374:Catalase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology* / Q000633:toxicity; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects*; D005875:Gibberellins / Q000096:biosynthesis; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D012275:Oryza / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013312:Stress, Physiological; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D005875:Gibberellins; D010940:Plant Proteins; D008315:Malondialdehyde; D000040:Abscisic Acid; D003300:Copper; D006861:Hydrogen Peroxide; D002374:Catalase; D000516:alpha-Amylases
keywords: Abscisic acid (ABA); Catalase; Copper; Reactive oxygen species; Rice (Oryza sativa); Seed germination