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The 1st International Electronic Conference on Plant Science (01/12/2020 - 15/12/2020): https://iecps2020.sciforum.net/
The 1st International Electronic Conference on Plant Science (01/12/2020 - 15/12/2020): https://iecps2020.sciforum.net/
The Acclimation Mechanisms of Chlamydomonas reinhardtii against Nitrosative Stress: A Role of NADPH Oxidase (RBOL2) in the Regulation of Nitric Oxide-Mediated ER Stress and Glutathione Redox State
The Acclimation Mechanisms of Chlamydomonas reinhardtii against Nitrosative Stress: A Role of NADPH Oxidase (RBOL2) in the Regulation of Nitric Oxide-Mediated ER Stress and Glutathione Redox State
Eva YuHua Kuo1, Wen-Chyi Dai1, Mu-Ting Lee2, Zheng Yu Yun2, Tse-Min Lee * 3
1 Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan2 Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan.3 Department of Marine Biotechnology and Resources, College of Marine Sciences, National Sun Yat-sen University, Kaohsiung 80424, TaiwanPublished: 30 November 2020 by MDPI in The 1st International Electronic Conference on Plant Science session Plant Nutrition, Plant Physiology and Metabolism
10.3390/IECPS2020-08609 (registering DOI)
Abstract:
Nitric oxide (NO) is a signal in the modulation of acclamatory responses to stress in plants. This study has investigated the metabolic shift in the acclimation of a green alga Chlamydomonas reinahrdii to NO stress. On exposure to 0.1 mM SNAP, a NO donor, causes a transient inhibition in photosynthesis after 1 h, followed by a fast recovery. The RNA-seq results discover that NO enhances the catabolism of cysteine, threonine, aromatic amino acids, and branched-chain amino acids to other metabolites for the synthesis of functional compounds. NO also induces the endosomal protein trafficking system in association with the ubiquitinylation machinery (ubiquitin, SNARE, and autophagy) for the degradation of sequestered damaged proteins to generate small molecules for re-synthesis of macromolecules, and triggers the protein modification system (heat proteins). The antioxidant defense system (VTC2, APX, MDAR, DHAR, GR, GPXH/GPX5, GSTS1, and GSTS2) and redox state (AsA/DHA and GSHH/GSSG) are activated by NO. Two PsbP-like proteins and LHCBM9 are induced for the acclimation to NO stress. Besides, THB, FLVb, and CYP55B1 are induced to reduce NO level for NO detoxification, allowing the acclimation to NO stress. NO significantly induced NADPH oxidase, RBOL2, but slightly decreased RBOL1 expression. Unfolded protein response (UPR) in response to ER stress was inhibited by NO stress. Using RBOL2 mutant, the UPR was induced and the glutathione synthesis and redox state was inhibited. This finding demonstrates that the NADPH oxidase (RBOL2)-mediated signaling pathway is involved in the NO-induced inhibition of ER stress and the induction of glutathione availability while other NO-induced metabolisms are under control by another signaling pathway. Our analyses provide a valuable tool for selecting genetic modification targets to understand acclamatory mechanisms to NO stress in Chlamydomonas.
Keywords: acclimation, antioxidant defense system, Chlamydomonas reinhardtii, ER stress, glutathione redox state, membrane trafficking system, nitrosative stress, photosynthesis, sulfur hemostasis, transcriptome
Plant Science Virtual 2020
September 10-11, 2020
Websute: https://plant-science-biology-conferences.magnusgroup.org/
Nitric oxide and reactive oxygen species regulation of NADPH oxidase for the high light induction of autophagy in Chlamydomonas reinhardtii
Eva YuHua Kuo1, Yu Yuan Zheng2 and Tse-Min Lee3
1Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, eyk1920@mail.nsysu.edu.tw
2Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, ybndhs56@gmail.com
3Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan; Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, tmee@mail.nsysu.edu.tw
Abstract: Nitric oxide (NO) is a signaling factors involved in the regulation of plant physiology and stress responses. The role of NO interaction with H2O2 in the regulation of NADPH oxidase (RBOL2) for the induction of autophagy and in Chlamydomonas reinhardtii was determined. Illumination of C. reinhardtii cells under a high light (HL, 1,600 µmol m−2 s −1) condition induced a NO burst through NO synthase- and nitrate reductase-independent routes, and cell death. The abundance of CrATG8 protein, an autophagy marker of C. reinhardtii, increased after HL illumination along with a linear increase in the transcript abundance of autophagy-associated genes, which can be suppressed in the presence of an NO scavenger, 2-(4-carboxyphenyl)- 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). The cells were treated with NO donor, S-nitroso-N-acetyl-penicillamine, under a normal light (50 µmol m−2 s −1) condition to elucidate the role of NO in autophagy activation and cell death. Treatment with 0.1 mM NO donor increased the abundance of ATG8 protein and CrATG transcripts, which can be suppressed by cPTIO, but did not influence cell viability. Treatment with 1 mM H2O2 and 0.1 mM NO donors enhanced autophagy induction and resulted in cell death after 24 h. This implies that NO is critical for the interaction of H2O2 and NO that induces cell death and autophagy. Furthermore, RBOL2 (NADPH oxidase) mutant showed enhanced autophagy expression. In conclusion, the present findings demonstrated that the NO interacts with H2O2 for HL-induced cell death and RBOL2 mediates the NO-induced autophagy in C. reinhardtii.
6th Edition of Global Conference on Plant Science and Molecular Biology
Sept 30-OCT 01, 2021
Website: https://plant-science-biology-conferences.magnusgroup.org/
NADPH oxidase-mediated signaling pathway mediates the high light activation of ascorbate-glutathione cycle (AGC) in Chlamydomonas reinhardtii against photo-oxidative stress
Eva YuHua Kuo1 and Tse-Min Lee2
1Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, eyk1920@mail.nsysu.edu.tw
2Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan; Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, tmee@mail.nsysu.edu.tw
The ascorbate-glutathione cycle (AGC) is essential for Chlamydomonas reinhardtii cells to cope with high light stress. NADPH oxidase acts as a key hub for the regulation of stress tolerance in plants. High-intensity illumination (HL, 1,200 mmol m-2 s-1) did not impact Chlamydomonas growth while the application of diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, in the concentration of 5 or 10 mM inhibited cell growth along with an increase of reactive oxygen species (ROS, O2.-, H2O2, and 1O2) and lipid peroxidation. The RNA-seq analysis and enzyme activity assay reveal that HL triggered an increase in CAT, APX, DHAR and GR enzyme activity and FeSOD (FSD1), APX1, DHAR1, and GSHR1 transcript abundances. But, the increase in the transcript abundances of APX1 and GSHR1 by HL was enhanced in the presence of DPI. The induction in the activity of enzymes in AGC can be inhibited in the presence of 10 mM DPI, accompanied by increased ROS production. However, the increase in the transcript abundances of FSD1, APX1, DHAR1, and GSHR1 under HL conditions can be enhanced in the presence of DPI. It reflects that NADPH oxidase-mediated signaling pathway modulates the induction of AGC in ways other than mRNA level. In conclusion, the present findings demonstrate that NADPH oxidase modulates the upregulation of the ascorbate-glutathione cycle for the acclimation of Chlamydomonas cells to photo-oxidative stress.
Chlamy 2020 19th International Conference on the Cell and Molecular Biology of ChlamydomonasNADPH oxidase-mediated signaling triggering of antioxidant defense and redox system in Chlamydomonas reinhardtii against photo-oxidative stress
Eva YuHua Kuo and Tse-Min Lee
Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan; Email: yhkuo0219@gmail.com (EYHK); tmlee@mail.nsysu.edu.tw (TML)
The antioxidant defense and redox system are induced in Chlamydomonas reinhardtii cells to cope with high-intensity illumination. NADPH oxidase is a key hub for stress acclimation in plants. High-light (HL, 1,200 mmol m-2 s-1) exposure slightly inhibited the growth of Chlamydomonas cells, while the presence of 10 mM diphenyleneiodonium (DPI), an NADPH oxidase inhibitor, resulted in cell death and significant oxidative stress, reflected by increased lipid peroxidation and over-production of reactive oxygen species (ROS, 1O2, O2.- and H2O2). According to the transcriptome assay (Illumina) of Chlamydomonas cells treated with DPI, the expression of the genes encoding glutathione-S-transferase (GSTS) and the enzymes in the biosynthesis of ascorbate (AsA, VTC2), glutathione (GSH, GSH1), tocopherol (VTE), and carotenoids (PSY, PDS) under HL condition were not under the control of NADPH oxidase-mediated singling pathway. However, the increase in the transcript abundances of glutathione peroxidase (GPX), thioredoxins (TRXs), glutaredoxin (GRXs), and methionine sulfoxide reductase (MSR) genes under HL condition was suppressed in the presence of DPI. In addition, the HL-induced upregulation of SOD expression was suppressed in the presence of DPI. For the ascorbate-glutathione cycle (AGC), the Illumina and qPCR analysis and the enzyme activity assay showed that the treatment of DPI inhibited the HL induction of ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) enzyme activity and APX1, DHAR, and GSHR1 transcript abundances. In conclusion, the present findings demonstrate that NADPH oxidase-mediated redox signaling pathway links to the upregulation of antioxidant defense and redox system in Chlamydomonas cells for the mitigation of HL-induced oxidative stress.
ASPB2021. July, 2021. (poster presentation)
NADPH oxidase associates with the modulation of antioxidant defense system in Chlamydomonas under high intensity illumination
Eva YuHua Kuo, Tsen-Hung Lin, and Tse-Min Lee
Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
The ascorbate-glutathione cycle (AGC) is essential for Chlamydomonas reinhardtii cells to cope with high light stress. NADPH oxidase acts as key hub for the regulation of stress tolerance in plants. High-intensity illumination (HL, 1,200 mmol m-2 s-1) did not impact Chlamydomonas growth while the application of diphenyleneiodonium (DPI), a NADPH oxidase inhibitor, in the concentration of 5 or 10 mM inhibited cell growth along with an increase of reactive oxygen species (ROS, O2.-, H2O2, and 1O2) and lipid peroxidation. The RNA-seq analysis and enzyme activity assay reveal that HL triggered an increase in CAT, APX, DHAR and GR enzyme activity and FeSOD (FSD1), APX1, DHAR1, and GSHR1 transcript abundances. But, the increase in the transcript abundances of APX1 and GSHR1 by HL was enhanced in the presence of DPI. The induction in the activity of enzymes in AGC can be inhibited in the presence of 10 mM DPI, accompanied with increased ROS production. However, the increase in the transcript abundances of FSD1, APX1, DHAR1, and GSHR1 under HL conditions can be enhanced in the presence of DPI. It reflects that NADPH oxidase-mediated signaling pathway modulates the induction of AGC in the ways other than mRNA level. In conclusion, the present findings demonstrate that NADPH oxidase modulates the upregulation of the ascorbate-glutathione cycle for the acclimation of Chlamydomonas cells to photo-oxidative stress.
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