Xiaodong Chen1, Dagang Tian2, Xiangxiang Kong3, Qian Chen3, Abd Allah E F4, Xiangyang Hu5, Aiqun Jia6. 1. School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China. 2. Biotechnology Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, 350003, Fujian, China. 3. The Germplasm Bank of Wild Species, Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Science, Kunming, 650201, China. 4. Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box. 2460, Riyadh, 11451, Saudi Arabia. 5. Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai, China. huxiangyang@mail.kib.ac.cn. 6. School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China. aiqunj302@mail.njust.edu.cn.
Abstract
MAIN CONCLUSION: Nitric oxide signal and GSNOR activity play an essential role for Chlamydomonas reinhardtii response to salt stress. The unicellular alga Chlamydomonas reinhardtii is one of the most important model organisms phylogenetically situated between higher plants and animals. In the present study, we used comparative proteomics and physiological approaches to study the mechanisms underlying the response to salt stress in C. reinhardtii. We identified 74 proteins that accumulated differentially after salt stress, including oxidative enzymes and enzymes associated with nitric oxide (NO) metabolism, cell damage, and cell autophagy processes. A set of antioxidant enzymes, as well as S-nitrosoglutathione reductase (GSNOR) activity, were induced to balance the cellular redox status during short-term salt stress. Enzymes involved in DNA repair and cell autophagy also contribute to adaptation to short-term salt stress. However, under long-term salt stress, antioxidant enzymes and GSNOR were gradually inactivated through protein S-nitrosylation, leading to oxidative damage and a reduction in cell viability. Modulating the protein S-nitrosylation levels by suppressing GSNOR activity or adding thioredoxin affected the plant's adaptation to salt stress, through altering the redox status and DNA damage and autophagy levels. Based on these data, we propose that unicellular algae use multiple strategies to adapt to salt stress, and that, during this process, GSNOR activity and protein S-nitrosylation levels play important roles.
MAIN CONCLUSION:Nitric oxide signal and GSNOR activity play an essential role for Chlamydomonas reinhardtii response to salt stress. The unicellular alga Chlamydomonas reinhardtii is one of the most important model organisms phylogenetically situated between higher plants and animals. In the present study, we used comparative proteomics and physiological approaches to study the mechanisms underlying the response to salt stress in C. reinhardtii. We identified 74 proteins that accumulated differentially after salt stress, including oxidative enzymes and enzymes associated with nitric oxide (NO) metabolism, cell damage, and cell autophagy processes. A set of antioxidant enzymes, as well as S-nitrosoglutathione reductase (GSNOR) activity, were induced to balance the cellular redox status during short-term salt stress. Enzymes involved in DNA repair and cell autophagy also contribute to adaptation to short-term salt stress. However, under long-term salt stress, antioxidant enzymes and GSNOR were gradually inactivated through protein S-nitrosylation, leading to oxidative damage and a reduction in cell viability. Modulating the protein S-nitrosylation levels by suppressing GSNOR activity or adding thioredoxin affected the plant's adaptation to salt stress, through altering the redox status and DNA damage and autophagy levels. Based on these data, we propose that unicellular algae use multiple strategies to adapt to salt stress, and that, during this process, GSNOR activity and protein S-nitrosylation levels play important roles.
Authors: Quang Tri Le; Won Je Lee; Jun Ho Choi; Dinh Thanh Nguyen; Hai An Truong; Sang-A Lee; Suk-Whan Hong; Hojoung Lee Journal: Front Plant Sci Date: 2022-01-24 Impact factor: 5.753