Arabidopsis Protein Phosphatase 2C ABI1 Interacts with Type I ACC Synthases and Is Involved in the Regulation of Ozone-Induced Ethylene Biosynthesis  

作　　者：Agnieszka Ludwikow Agata Ciesla Anna Kasprowicz-Malusk Filip Mitula Malgorzata Tajdel lukasz Gaigarnski Piotr A. Ziolkowski Piotr Kubiak Arleta Malecka Aneta Piechalak Marta Szabat Alicja Gorska Maciej Dabrowskia Izabela Ibragimow Jan Sadowski 

机构地区：[1]Department of Biotechnology, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University inPoznan, Umultowska 89, 61-614 Poznan, Poland [2]Institute of Plant Genetics Polish Academy of Science, Strzeszynska 34, 60-479 Poznan, Poland [3]Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam MickiewiczUniversity in Poznan, Umultowska 89, 61-614 Poznan, Poland [4]Department of Biotechnology and Food Microbiology, University of Life Sciences, Wojska Polskiego 48, 60-627 Poznan, Poland [5]Department of Biochemistry, Institute of Molecular Bioloqy and Biotechnology, Faculty of Bioloqy, Adam Mickiewicz University inPoznan, Umultowska 89, 61-614 Poznan, Poland

出　　处：《Molecular Plant》2014年第6期960-976,共17页分子植物（英文版）

摘　　要：Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regu- lated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosynthesis, impacts 1-aminocyclopropane 1-carboxylate synthase （ACS） protein stability via the complex interplay of specific factors. Here, we show that the Arabidopsis thaliana protein phosphatase type 2C, ABI1, a negative regulator of abscisic acid signaling, is involved in the regulation of ethylene biosynthesis under oxidative stress conditions. We found that ABI1 interacts with ACS6 and dephosphorylates its C-terminal fragment, a target of the stress-responsive mitogen-activated protein kinase, MPK6. In addition, ABI1 controls MPK6 activity directly and by this means also affects the ACS6 phosphorylation level. Consistently with this, ozone-induced ethylene production was significantly higher in an ABI1 knockout strain （abiltd） than in wild-type plants. Importantly, an increase in stress-induced ethylene production in the abiltd mutant was compen- sated by a higher ascorbate redox state and elevated antioxidant activities. Overall, the results of this study provide evi- dence that ABI1 restricts ethylene synthesis by affecting the activity of ACS6. The ABI1 contribution to stress phenotype underpins its role in the interplay between the abscisic acid （ABA） and ethylene signaling pathways.Ethylene plays a crucial role in various biological processes and therefore its biosynthesis is strictly regu- lated by multiple mechanisms. Posttranslational regulation, which is pivotal in controlling ethylene biosynthesis, impacts 1-aminocyclopropane 1-carboxylate synthase （ACS） protein stability via the complex interplay of specific factors. Here, we show that the Arabidopsis thaliana protein phosphatase type 2C, ABI1, a negative regulator of abscisic acid signaling, is involved in the regulation of ethylene biosynthesis under oxidative stress conditions. We found that ABI1 interacts with ACS6 and dephosphorylates its C-terminal fragment, a target of the stress-responsive mitogen-activated protein kinase, MPK6. In addition, ABI1 controls MPK6 activity directly and by this means also affects the ACS6 phosphorylation level. Consistently with this, ozone-induced ethylene production was significantly higher in an ABI1 knockout strain （abiltd） than in wild-type plants. Importantly, an increase in stress-induced ethylene production in the abiltd mutant was compen- sated by a higher ascorbate redox state and elevated antioxidant activities. Overall, the results of this study provide evi- dence that ABI1 restricts ethylene synthesis by affecting the activity of ACS6. The ABI1 contribution to stress phenotype underpins its role in the interplay between the abscisic acid （ABA） and ethylene signaling pathways.

关 键 词：hormonal regulation protein phosphorylation/dephosphorylation signal transduction Arabidopsis. 

分 类 号：Q556.2[生物学—生物化学] S665.209.3[农业科学—果树学]