Juanjuan Yu1,2, Yongxue Zhang1,2, Junming Liu1, Lin Wang1, Panpan Liu1, Zepeng Yin1, Siyi Guo3, Jun Ma4, Zhuang Lu5, Tai Wang5, Yimin She4, Yuchen Miao3, Ling Ma1, Sixue Chen6, Ying Li7, Shaojun Dai8,9. 1. Alkali Soil Natural Environmental Science Center, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Northeast Forestry University, Harbin, 150040, China. 2. Development Centre of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China. 3. Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, Kaifeng, 455000, China. 4. Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China. 5. Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China. 6. Department of Biology, Genetics Institute, Plant Molecular and Cellular Program, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32610, USA. 7. Alkali Soil Natural Environmental Science Center, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Northeast Forestry University, Harbin, 150040, China. ly7966@nefu.edu.cn. 8. Alkali Soil Natural Environmental Science Center, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, Northeast Forestry University, Harbin, 150040, China. daishaojun@hotmail.com. 9. Development Centre of Plant Germplasm Resources, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, 200234, China. daishaojun@hotmail.com.
Abstract
MAIN CONCLUSION: Hydrogen peroxide-responsive pathways in roots of alkaligrass analyzed by proteomic studies and PutGLP enhance the plant tolerance to saline-, alkali- and cadmium-induced oxidative stresses. Oxidative stress adaptation is critical for plants in response to various stress environments. The halophyte alkaligrass (Puccinellia tenuiflora) is an outstanding pasture with strong tolerance to salt and alkali stresses. In this study, iTRAQ- and 2DE-based proteomics approaches, as well as qRT-PCR and molecular genetics, were employed to investigate H2O2-responsive mechanisms in alkaligrass roots. The evaluation of membrane integrity and reactive oxygen species (ROS)-scavenging systems, as well as abundance patterns of H2O2-responsive proteins/genes indicated that Ca2+-mediated kinase signaling pathways, ROS homeostasis, osmotic modulation, and transcriptional regulation were pivotal for oxidative adaptation in alkaligrass roots. Overexpressing a P. tenuiflora germin-like protein (PutGLP) gene in Arabidopsis seedlings revealed that the apoplastic PutGLP with activities of oxalate oxidase and superoxide dismutase was predominantly expressed in roots and played important roles in ROS scavenging in response to salinity-, alkali-, and CdCl2-induced oxidative stresses. The results provide insights into the fine-tuned redox-responsive networks in halophyte roots.
MAIN CONCLUSION: Hydrogen peroxide-responsive pathways in roots of alkaligrass analyzed by proteomic studies and PutGLP enhance the plant tolerance to saline-, alkali- and cadmium-induced oxidative stresses. Oxidative stress adaptation is critical for plants in response to various stress environments. The halophyte alkaligrass (Puccinellia tenuiflora) is an outstanding pasture with strong tolerance to salt and alkali stresses. In this study, iTRAQ- and 2DE-based proteomics approaches, as well as qRT-PCR and molecular genetics, were employed to investigate H2O2-responsive mechanisms in alkaligrass roots. The evaluation of membrane integrity and reactive oxygen species (ROS)-scavenging systems, as well as abundance patterns of H2O2-responsive proteins/genes indicated that Ca2+-mediated kinase signaling pathways, ROS homeostasis, osmotic modulation, and transcriptional regulation were pivotal for oxidative adaptation in alkaligrass roots. Overexpressing a P. tenuiflora germin-like protein (PutGLP) gene in Arabidopsis seedlings revealed that the apoplastic PutGLP with activities of oxalate oxidase and superoxide dismutase was predominantly expressed in roots and played important roles in ROS scavenging in response to salinity-, alkali-, and CdCl2-induced oxidative stresses. The results provide insights into the fine-tuned redox-responsive networks in halophyte roots.