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Yuan X, Xu J, Yu J, Zhu D, Li H, Zhao Q. The NAC transcription factor ZmNAC132 regulates leaf senescence and male fertility in maize. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023:111774. [PMID: 37331633 DOI: 10.1016/j.plantsci.2023.111774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/20/2023]
Abstract
Leaf senescence is an integral step in the final stages of plant development, as nutrient remobilization from leaves to sink organs is accomplished during this process. NACs compose a large superfamily of plant-specific TFs involved in multiple plant development processes. Here, we identified a maize NAC TF, ZmNAC132, involved in leaf senescence and male fertility. ZmNAC132 expression was tightly linked to leaf senescence in an age-dependent manner. Knockout of ZmNAC132 led to delays in chlorophyll degradation and leaf senescence, whereas overexpression of ZmNAC132 had the opposite effects. ZmNAC132 could bind to and transactivate the promoter of ZmNYE1, a major chlorophyll catabolic gene, to accelerate chlorophyll degradation during leaf senescence. Moreover, ZmNAC132 affected male fertility through the upregulation of ZmEXPB1, an expansin-encoding gene associated with sexual reproduction and other related genes. Together, the results show that ZmNAC132 participates in the regulation of leaf senescence and male fertility through the targeting of different downstream genes in maize.
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Affiliation(s)
- Xiaohong Yuan
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jianghai Xu
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Jingjuan Yu
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Dengyun Zhu
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Hongjie Li
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Qian Zhao
- State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.
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2
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Dey D, Nishijima M, Tanaka R, Kurisu G, Tanaka H, Ito H. Crystal structure and reaction mechanism of a bacterial Mg-dechelatase homolog from the Chloroflexi Anaerolineae. Protein Sci 2022; 31:e4430. [PMID: 36173179 PMCID: PMC9514216 DOI: 10.1002/pro.4430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/05/2022]
Abstract
Chlorophyll degradation plays a myriad of physiological roles in photosynthetic organisms, including acclimation to light environment and nutrient remobilization during senescence. Mg extraction from chlorophyll a is the first and committed step of the chlorophyll degradation pathway. This reaction is catalyzed by the Mg-dechelatase enzyme encoded by Stay-Green (SGR). The reaction mechanism of SGR protein remains elusive since metal ion extraction from organic molecules is not a common enzymatic reaction. Additionally, experimentally derived structural information about SGR or its homologs has not yet been reported. In this study, the crystal structure of the SGR homolog from Anaerolineae bacterium was determined using the molecular replacement method at 1.85 Å resolution. Our previous study showed that three residues-H32, D34, and D62 are essential for the catalytic activity of the enzyme. Biochemical analysis involving mutants of D34 residue further strengthened its importance in the functioning of the dechelatase. Docking simulation also revealed the interaction between the D34 side chain and central Mg ion of chlorophyll a. Structural analysis showed the arrangement of D34/H32/D62 in the form of a catalytic triad that is generally found in hydrolases. The probable reaction mechanism suggests that deprotonated D34 side chain coordinates and destabilizes Mg, resulting in Mg extraction. Besides, H32 possibly acts as a general base catalyst and D62 facilitates H32 to be a better proton acceptor. Taken together, the reaction mechanism of SGR partially mirrors the one observed in hydrolases.
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Affiliation(s)
- Debayan Dey
- Graduate School of Life ScienceHokkaido UniversitySapporoJapan
- Institute of Low Temperature ScienceHokkaido UniversitySapporoJapan
| | | | - Ryouichi Tanaka
- Institute of Low Temperature ScienceHokkaido UniversitySapporoJapan
| | - Genji Kurisu
- Institute for Protein ResearchOsaka UniversitySuitaJapan
| | - Hideaki Tanaka
- Institute for Protein ResearchOsaka UniversitySuitaJapan
| | - Hisashi Ito
- Institute of Low Temperature ScienceHokkaido UniversitySapporoJapan
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3
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Yamatani H, Ito T, Nishimura K, Yamada T, Sakamoto W, Kusaba M. Genetic analysis of chlorophyll synthesis and degradation regulated by BALANCE of CHLOROPHYLL METABOLISM. PLANT PHYSIOLOGY 2022; 189:419-432. [PMID: 35348770 PMCID: PMC9070834 DOI: 10.1093/plphys/kiac059] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 05/05/2023]
Abstract
Chlorophyll (Chl) serves a number of essential functions, capturing and converting light energy as a component of photosystem supercomplexes. Chl degradation during leaf senescence is also required for adequate degeneration of chloroplasts and salvaging of nutrients from senescent leaves. In this study, we performed genetic analysis to determine the functions of BALANCE of CHLOROPHYLL METABOLISM1 (BCM1) and BCM2, which control Chl levels by regulating synthesis and degradation, and STAY-GREEN (SGR)1 (also known as NON-YELLOWING1 [NYE1]) and SGR2, which encode Mg-dechelatase and catalyze Chl a degradation in Arabidopsis (Arabidopsis thaliana). Analysis of bcm1 bcm2 revealed that both BCM1 and BCM2 are involved in the regulation of Chl levels in presenescent leaves and Chl degradation in senescing leaves. Analysis of bcm1 bcm2 nye1 nye2 suggested that BCMs repress Chl-degrading activity in both presenescent and senescing leaves by regulating SGR activity. Furthermore, transactivation analysis and chromatin immunoprecipitation (ChIP) assay revealed that GOLDEN2-LIKE1 (GLK1), a central transcription factor regulating the expression of genes encoding photosystem-related proteins, such as light-harvesting Chl a/b-binding proteins (LHCPs), directly regulates the transcription of BCM1. LHCPs are stabilized by Chl binding, suggesting that GLKs control the amount of LHCP through transcriptional and post-translational regulation via BCM-mediated Chl-level regulation. Meanwhile, we generated a mutant of the BCM ortholog in lettuce (Lactuca sativa) by genome editing and found that it showed an early yellowing phenotype, but only a slight reduction in Chl in presenescent leaves. Thus, this study revealed a conserved but slightly diversified regulation of Chl and LHCP levels via the GLK-BCM pathway in eudicots.
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Affiliation(s)
| | - Takeshi Ito
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima 739-8526, Japan
| | | | - Tetsuya Yamada
- Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
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Zhang J, Li H, Huang X, Xing J, Yao J, Yin T, Jiang J, Wang P, Xu B. STAYGREEN-mediated chlorophyll a catabolism is critical for photosystem stability during heat-induced leaf senescence in perennial ryegrass. PLANT, CELL & ENVIRONMENT 2022; 45:1412-1427. [PMID: 35192197 DOI: 10.1111/pce.14296] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/23/2022] [Accepted: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Suppression of the chlorophyll a (Chl a) Mg-dechelatase gene, SGR/NYE1, blocks the degradation of Chl a, resulting in a 'stay-green' trait. In this study, we investigated the effect of Chl a catabolism on plant heat-induced leaf senescence in perennial ryegrass (Lolium perenne L.). Under heat stress, the LpSGR-RNAi lines not only lost the stay-green phenotype but also showed accelerated leaf senescence with increased chloroplast disruption, more loss of photosystem (PS) proteins, lower PSⅡ quantum yields, higher levels of energy dissipation, increased accumulation of reactive oxygen species (ROS) and lower ROS-scavenging enzyme activities. Transcriptome analysis revealed that the suppression of LpSGR downregulated genes encoding PS proteins and ROS-scavenging enzymes and upregulated those encoding ROS-generation enzymes under heat stress. To account for the possible side-effects resulting from constitutive suppression of LpSGR on plant growth and heat tolerance, we constructed an ethanol-inducible RNAi vector to suppress LpSGR functions. In the absence of ethanol induction, these lines exhibited the same growth and heat tolerance as the wildtype (WT). Upon ethanol induction, the transgenic lines showed compromised heat tolerance and a postharvest stay-green phenotype. Taken together, SGR-mediated Chl a catabolism is required for plant heat tolerance.
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Affiliation(s)
- Jing Zhang
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Hui Li
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Xinru Huang
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Jing Xing
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Jiaming Yao
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Tingchao Yin
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
| | - Jiafu Jiang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Puchang Wang
- Guizhou Institute of Prataculture, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Bin Xu
- College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, China
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Schumacher I, Menghini D, Ovinnikov S, Hauenstein M, Fankhauser N, Zipfel C, Hörtensteiner S, Aubry S. Evolution of chlorophyll degradation is associated with plant transition to land. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:1473-1488. [PMID: 34931727 PMCID: PMC9306834 DOI: 10.1111/tpj.15645] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/09/2021] [Accepted: 12/15/2021] [Indexed: 05/27/2023]
Abstract
Chlorophyll, the central pigment of photosynthesis, is highly photo‐active and degraded enzymatically during leaf senescence. Merging comparative genomics and metabolomics, we evaluate the extent to which the chlorophyll detoxification pathway has evolved in Viridiplantae. We argue that cytosolic detoxification of phyllobilins in particular was a critical process to the green lineage’s transition to land.
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Affiliation(s)
- Isabel Schumacher
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Damian Menghini
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Serguei Ovinnikov
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Mareike Hauenstein
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Niklaus Fankhauser
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Cyril Zipfel
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Stefan Hörtensteiner
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
| | - Sylvain Aubry
- Department of Plant and Microbial BiologyUniversity of ZürichZürich8008Switzerland
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6
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Nawrocki WJ, Liu X, Raber B, Hu C, de Vitry C, Bennett DIG, Croce R. Molecular origins of induction and loss of photoinhibition-related energy dissipation q I. SCIENCE ADVANCES 2021; 7:eabj0055. [PMID: 34936440 PMCID: PMC8694598 DOI: 10.1126/sciadv.abj0055] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Photosynthesis fuels life on Earth using sunlight as energy source. However, light has a simultaneous detrimental effect on the enzyme triggering photosynthesis and producing oxygen, photosystem II (PSII). Photoinhibition, the light-dependent decrease of PSII activity, results in a major limitation to aquatic and land photosynthesis and occurs upon all environmental stress conditions. In this work, we investigated the molecular origins of photoinhibition focusing on the paradoxical energy dissipation process of unknown nature coinciding with PSII damage. Integrating spectroscopic, biochemical, and computational approaches, we demonstrate that the site of this quenching process is the PSII reaction center. We propose that the formation of quenching and the closure of PSII stem from the same event. We lastly reveal the heterogeneity of PSII upon photoinhibition using structure-function modeling of excitation energy transfer. This work unravels the functional details of the damage-induced energy dissipation at the heart of photosynthesis.
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Affiliation(s)
- Wojciech J. Nawrocki
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- Corresponding author. (W.J.N.); (R.C.)
| | - Xin Liu
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Bailey Raber
- Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX, USA
| | - Chen Hu
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Catherine de Vitry
- Institut de Biologie Physico-Chimique, UMR 7141, CNRS-Sorbonne Université, 75005 Paris, France
| | - Doran I. G. Bennett
- Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX, USA
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- Corresponding author. (W.J.N.); (R.C.)
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7
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Research Progress in the Interconversion, Turnover and Degradation of Chlorophyll. Cells 2021; 10:cells10113134. [PMID: 34831365 PMCID: PMC8621299 DOI: 10.3390/cells10113134] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 01/01/2023] Open
Abstract
Chlorophylls (Chls, Chl a and Chl b) are tetrapyrrole molecules essential for photosynthetic light harvesting and energy transduction in plants. Once formed, Chls are noncovalently bound to photosynthetic proteins on the thylakoid membrane. In contrast, they are dismantled from photosystems in response to environmental changes or developmental processes; thus, they undergo interconversion, turnover, and degradation. In the last twenty years, fruitful research progress has been achieved on these Chl metabolic processes. The discovery of new metabolic pathways has been accompanied by the identification of enzymes associated with biochemical steps. This article reviews recent progress in the analysis of the Chl cycle, turnover and degradation pathways and the involved enzymes. In addition, open questions regarding these pathways that require further investigation are also suggested.
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8
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Tian YN, Zhong RH, Wei JB, Luo HH, Eyal Y, Jin HL, Wu LJ, Liang KY, Li YM, Chen SZ, Zhang ZQ, Pang XQ. Arabidopsis CHLOROPHYLLASE 1 protects young leaves from long-term photodamage by facilitating FtsH-mediated D1 degradation in photosystem II repair. MOLECULAR PLANT 2021; 14:1149-1167. [PMID: 33857689 DOI: 10.1016/j.molp.2021.04.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
The proteolytic degradation of the photodamaged D1 core subunit during the photosystem II (PSII) repair cycle is well understood, but chlorophyll turnover during D1 degradation remains unclear. Here, we report that Arabidopsis thaliana CHLOROPHYLLASE 1 (CLH1) plays important roles in the PSII repair process. The abundance of CLH1 and CLH2 peaks in young leaves and is induced by high-light exposure. Seedlings of clh1 single and clh1-1/2-2 double mutants display increased photoinhibition after long-term high-light exposure, whereas seedlings overexpressing CLH1 have enhanced light tolerance compared with the wild type. CLH1 is localized in the developing chloroplasts of young leaves and associates with the PSII-dismantling complexes RCC1 and RC47, with a preference for the latter upon exposure to high light. Furthermore, degradation of damaged D1 protein is retarded in young clh1-1/2-2 leaves after 18-h high-light exposure but is rescued by the addition of recombinant CLH1 in vitro. Moreover, overexpression of CLH1 in a variegated mutant (var2-2) that lacks thylakoid protease FtsH2, with which CLH1 interacts, suppresses the variegation and restores D1 degradation. A var2-2 clh1-1/2-2 triple mutant shows more severe variegation and seedling death. Taken together, these results establish CLH1 as a long-sought chlorophyll dephytylation enzyme that is involved in PSII repair and functions in long-term adaptation of young leaves to high-light exposure by facilitating FtsH-mediated D1 degradation.
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Affiliation(s)
- Ya-Nan Tian
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Rui-Hao Zhong
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Jun-Bin Wei
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Hong-Hui Luo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Horticulture, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Yoram Eyal
- Institute of Plant Sciences, The Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
| | - Hong-Lei Jin
- Institute of Medical Plant Physiology and Ecology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, People's Republic of China
| | - La-Jie Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Ke-Ying Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Ying-Man Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Shu-Zhen Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Zhao-Qi Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Horticulture, South China Agricultural University, Guangzhou 510642, People's Republic of China.
| | - Xue-Qun Pang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, South China Agricultural University, Guangzhou 510642, People's Republic of China; College of Life Sciences, South China Agricultural University, Guangzhou 510642, People's Republic of China.
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9
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Chen Y, Yamori W, Tanaka A, Tanaka R, Ito H. Degradation of the photosystem II core complex is independent of chlorophyll degradation mediated by Stay-Green Mg 2+ dechelatase in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 307:110902. [PMID: 33902860 DOI: 10.1016/j.plantsci.2021.110902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/15/2021] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
During leaf senescence, the degradation of photosystems and photosynthetic pigments proceeds in a coordinated manner, which would minimize the potential photodamage to cells. Both photosystem I and II are composed of core complexes and peripheral antenna complexes, with the former binding chlorophyll a and the latter binding chlorophyll a and b. Although the degradation of peripheral antenna complexes is initiated by chlorophyll degradation, it remains unclear whether the degradation of core complexes and chlorophyll is coordinated. In this study, we examined the degradation of peripheral antenna and core complexes in the Arabidopsis sgr1/sgr2/sgrl triple mutant, lacking all the isoforms of chlorophyll a:Mg2+ dechelatase. In this mutant, the degradation of peripheral antenna complexes and photosystem I core complexes was substantially retarded, but the core complexes of photosystem II were rapidly degraded during leaf senescence. On the contrary, the photosynthetic activity declined at a similar rate as in the wild type plants. These results suggest that the degradation of photosystem II core complexes is regulated independently of the major chlorophyll degradation pathway mediated by the dechelatase. The study should contribute to the understanding of the complex molecular mechanisms underlying the degradation of photosystems, which is an essential step during leaf senescence.
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Affiliation(s)
- Ying Chen
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Wataru Yamori
- Institute for Sustainable Agro-Ecosystem Services, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Ayumi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Ryouichi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan.
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10
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Wang P, Grimm B. Connecting Chlorophyll Metabolism with Accumulation of the Photosynthetic Apparatus. TRENDS IN PLANT SCIENCE 2021; 26:484-495. [PMID: 33422426 DOI: 10.1016/j.tplants.2020.12.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/20/2020] [Accepted: 12/09/2020] [Indexed: 05/14/2023]
Abstract
Chlorophyll (Chl) is indispensable for photosynthesis. In association with Chl-binding proteins (CBPs), it is responsible for light absorption, excitation energy transfer, and charge separation within the photosynthetic complexes. By contrast, photoexcitation of free Chl and its metabolic intermediates generates hazardous reactive oxygen species (ROS). While antagonistic activities of Chl synthesis and catabolism have been mostly elucidated, the tight synchronization of these metabolic activities with the formation and dismantling of the photosynthetic complexes is poorly understood. Recently, a set of auxiliary factors were identified to adjust metabolic activities and provide accurate amounts of Chl for pigment-protein complexes. Here, we review current knowledge of post-translational coordination of Chl formation, breakdown, and turnover with the assembly and disassembly of various CBPs and highlight future research perspectives.
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Affiliation(s)
- Peng Wang
- Humboldt-Universität zu Berlin, Institute of Biology/Plant Physiology, Philippstraße 13 Building 12, 10115 Berlin, Germany.
| | - Bernhard Grimm
- Humboldt-Universität zu Berlin, Institute of Biology/Plant Physiology, Philippstraße 13 Building 12, 10115 Berlin, Germany.
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11
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Lin YP, Charng YY. Chlorophyll dephytylation in chlorophyll metabolism: a simple reaction catalyzed by various enzymes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 302:110682. [PMID: 33288004 DOI: 10.1016/j.plantsci.2020.110682] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/12/2020] [Accepted: 09/14/2020] [Indexed: 05/21/2023]
Abstract
Chlorophyll (Chl) is composed of a tetrapyrrole ring and a phytol tail, which facilitate light energy absorbance and assembly with photosynthetic protein complexes, respectively. Chl dephytylation, the hydrolytic removal of the phytol tail, is considered a pivotal step in diverse physiological processes, such as Chl salvage during repair of the photosystem, the Chl cycle in the adjustment of antenna size, and Chl breakdown in leaf senescence and fruit maturation. Moreover, phytol is a component of the tocopherols, a major form of vitamin E that is essential in the human diet. This phytol mostly comes from Chl hydrolysis. However, the authentic enzyme responsible for Chl dephytylation has proved elusive. CHLOROPHYLLASE (CLH) which was discovered over a century ago, was the first enzyme found to have dephytylation activity in vitro, but its role in Chl metabolism has been questioned and remains under debate. Recently, novel dephytylases, i.e., PHEOPHYTINASE (PPH) and CHLOROPHYLL DEPHYTYLASE1 (CLD1) have emerged from genetic studies, indicating that dephytylation in Chl catabolism involves different players and is more complicated than previously thought. Based on sequence homology, substrate specificity, and subcellular localization, CLH, PPH, and CLD1 belong to different types of dephytylase, which prompted us to re-examine the dilemmas and missing links that still exist in Chl metabolism. This review thus focuses on the hitherto unanswered questions involving the Chl dephytylation reaction by highlighting relevant literature, updating recent progress, and synthesizing ideas.
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Affiliation(s)
- Yao-Pin Lin
- Institut of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Germany; Agricultural Biotechnology Research Center, Academia Sinica, Taiwan, ROC.
| | - Yee-Yung Charng
- Agricultural Biotechnology Research Center, Academia Sinica, Taiwan, ROC.
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12
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Jiao B, Meng Q, Lv W. Roles of stay-green (SGR) homologs during chlorophyll degradation in green plants. BOTANICAL STUDIES 2020; 61:25. [PMID: 32965575 PMCID: PMC7511501 DOI: 10.1186/s40529-020-00302-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 09/18/2020] [Indexed: 05/29/2023]
Abstract
Chlorophyll (Chl) degradation is one of the most obvious signs of leaf senescence and fruit ripening. Stay-green (SGR) homologs that can remove magnesium from Chl a are the most important components in Chl degradation pathway in green plants. SGR homologs are not only universally involved in Chl breakdown during the senescence of green organs, but also play crucial roles in other organs during plant growth and development, such as fruit mature and nodule development. In this review, we focus on the diverse functions of SGR homologs in plant growth and development. A better understanding of SGR would be helpful for providing a theoretical basis for further illustrating the regulatory mechanism of SGR homologs.
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Affiliation(s)
- Baozhen Jiao
- State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Daizong Street, Tai’an, 271018 Shandong People’s Republic of China
| | - Qingwei Meng
- State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Daizong Street, Tai’an, 271018 Shandong People’s Republic of China
| | - Wei Lv
- State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Daizong Street, Tai’an, 271018 Shandong People’s Republic of China
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13
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Sun C, Xu Y, Hu N, Ma J, Sun S, Cao W, Klobučar G, Hu C, Zhao Y. To evaluate the toxicity of atrazine on the freshwater microalgae Chlorella sp. using sensitive indices indicated by photosynthetic parameters. CHEMOSPHERE 2020; 244:125514. [PMID: 31812061 DOI: 10.1016/j.chemosphere.2019.125514] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Atrazine is a widely-applied herbicide used primarily to control weeds, which can persist in the ecosystem and exert potential toxicity to phytoplankton in the aquatic environment. In this study, acute toxicity of atrazine on microalgae Chlorella sp. was investigated with different initial cell densities (1 × 105 and 1 × 106 cells mL-1) and exposure periods (4 d and 8 d). Both growth rate and photosynthetic parameters of the microalgae in response of atrazine stress were determined to find out the sensitive indices and toxicological mechanisms. Because of the independence of initial cell density as well as the high sensitivity and reliability, the performance index PIABS was verified as the most convincing photosynthetic parameter for indicating IC50 of atrazine on Chlorella sp., being superior to the traditional parameters of growth rate and FV/FM. The IP amplitude (ΔFIP, fluorescence amplitude of the I-to-P-rise in the OJIP curve) was another sensitive biomarker to reflect atrazine stress. Results from chlorophyll fluorescence transient revealed that atrazine damaged the photosystem II (PS II) reaction center, suppressed the electron transport at the donor and receptor sides, and acted on the absorption, transfer, and utilization of light energy. Our results provide confirmatory references for understanding the toxicity and mechanisms of atrazine on freshwater microalgae.
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Affiliation(s)
- Chen Sun
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China
| | - Yinfeng Xu
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China
| | - Naitao Hu
- School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, PR China
| | - Jun Ma
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China
| | - Shiqing Sun
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China
| | - Weixing Cao
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China
| | - Göran Klobučar
- Department of Biology, Faculty of Science, University of Zagreb, Croatia
| | - Changwei Hu
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China.
| | - Yongjun Zhao
- College of Biological, Chemical Science and Engineering, Jiaxing University, Jiaxing, 314001, PR China.
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Wang P, Richter AS, Kleeberg JRW, Geimer S, Grimm B. Post-translational coordination of chlorophyll biosynthesis and breakdown by BCMs maintains chlorophyll homeostasis during leaf development. Nat Commun 2020; 11:1254. [PMID: 32198392 PMCID: PMC7083845 DOI: 10.1038/s41467-020-14992-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 02/11/2020] [Indexed: 12/20/2022] Open
Abstract
Chlorophyll is indispensable for life on Earth. Dynamic control of chlorophyll level, determined by the relative rates of chlorophyll anabolism and catabolism, ensures optimal photosynthesis and plant fitness. How plants post-translationally coordinate these two antagonistic pathways during their lifespan remains enigmatic. Here, we show that two Arabidopsis paralogs of BALANCE of CHLOROPHYLL METABOLISM (BCM) act as functionally conserved scaffold proteins to regulate the trade-off between chlorophyll synthesis and breakdown. During early leaf development, BCM1 interacts with GENOMES UNCOUPLED 4 to stimulate Mg-chelatase activity, thus optimizing chlorophyll synthesis. Meanwhile, BCM1’s interaction with Mg-dechelatase promotes degradation of the latter, thereby preventing chlorophyll degradation. At the onset of leaf senescence, BCM2 is up-regulated relative to BCM1, and plays a conserved role in attenuating chlorophyll degradation. These results support a model in which post-translational regulators promote chlorophyll homeostasis by adjusting the balance between chlorophyll biosynthesis and breakdown during leaf development. Plants regulate chlorophyll levels to optimise photosynthesis. Here Wang et al. describe two paralogous thylakoid proteins, BCM1 and BCM2, which stimulate chlorophyll biosynthesis and attenuate chlorophyll degradation respectively through interaction with the Mg-chelatase-stimulating factor GUN4 and Mg-dechelatase isoform SGR1.
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Affiliation(s)
- Peng Wang
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.
| | - Andreas S Richter
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.,Institute of Biology/Physiology of Plant Cell Organelles, Humboldt-Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany
| | - Julius R W Kleeberg
- Zellbiologie/Elektronenmikroskopie, Universität Bayreuth, 95440, Bayreuth, Germany
| | - Stefan Geimer
- Zellbiologie/Elektronenmikroskopie, Universität Bayreuth, 95440, Bayreuth, Germany
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt-Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.
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15
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Obata D, Takabayashi A, Tanaka R, Tanaka A, Ito H. Horizontal Transfer of Promiscuous Activity from Nonphotosynthetic Bacteria Contributed to Evolution of Chlorophyll Degradation Pathway. Mol Biol Evol 2020; 36:2830-2841. [PMID: 31432082 DOI: 10.1093/molbev/msz193] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The relationship between enzymes and substrates does not perfectly match the "lock and key" model, because enzymes act on molecules other than their true substrate in different catalytic reactions. Such biologically nonfunctional reactions are called "promiscuous activities." Promiscuous activities are apparently useless, but they can be an important starting point for enzyme evolution. It has been hypothesized that enzymes with low promiscuous activity will show enhanced promiscuous activity under selection pressure and become new specialists through gene duplication. Although this is the prevailing scenario, there are two major problems: 1) it would not apply to prokaryotes because horizontal gene transfer is more significant than gene duplication and 2) there is no direct evidence that promiscuous activity is low without selection pressure. We propose a new scenario including various levels of promiscuous activity throughout a clade and horizontal gene transfer. STAY-GREEN (SGR), a chlorophyll a-Mg dechelating enzyme, has homologous genes in bacteria lacking chlorophyll. We found that some bacterial SGR homologs have much higher Mg-dechelating activities than those of green plant SGRs, while others have no activity, indicating that the level of promiscuous activity varies. A phylogenetic analysis suggests that a bacterial SGR homolog with high dechelating activity was horizontally transferred to a photosynthetic eukaryote. Some SGR homologs acted on various chlorophyll molecules that are not used as substrates by green plant SGRs, indicating that SGR acquired substrate specificity after transfer to eukaryotes. We propose that horizontal transfer of high promiscuous activity is one process of new enzyme acquisition.
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Affiliation(s)
- Daichi Obata
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | | | - Ryouichi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Ayumi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
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16
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Xie Z, Wu S, Chen J, Zhu X, Zhou X, Hörtensteiner S, Ren G, Kuai B. The C-terminal cysteine-rich motif of NYE1/SGR1 is indispensable for its function in chlorophyll degradation in Arabidopsis. PLANT MOLECULAR BIOLOGY 2019; 101:257-268. [PMID: 31302867 DOI: 10.1007/s11103-019-00902-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/09/2019] [Indexed: 05/08/2023]
Abstract
The C-terminal cysteine-rich motif of NYE1/SGR1 affects chlorophyll degradation likely by mediating its self-interaction and conformational change, and somehow altering its Mg-dechelating activity in response to the changing redox potential. During green organ senescence in plants, the most prominent phenomenon is the degreening caused by net chlorophyll (Chl) loss. NON-YELLOWING1/STAY-GREEN1 (NYE1/SGR1) was recently reported to be able to dechelates magnesium (Mg) from Chl a to initiate its degradation, but little is known about the domain/motif basis of its functionality. In this study, we carried out a protein truncation assay and identified a conserved cysteine-rich motif (CRM, P-X3-C-X3-C-X-C2-F-P-X5-P) at its C terminus, which is essential for its function. Genetic analysis showed that all four cysteines in the CRM were irreplaceable, and enzymatic assays demonstrated that the mutation of each of the four cysteines affected its Mg-dechelating activity. The CRM plays a critical role in the conformational change and self-interaction of NYE1 via the formation of inter- and intra-molecular disulfide bonds. Our results may provide insight into how NYE1 responds to rapid redox changes during leaf senescence and in response to various environmental stresses.
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Affiliation(s)
- Zuokun Xie
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China
| | - Shengdong Wu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China
| | - Junyi Chen
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China
| | - Xiaoyu Zhu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China
| | - Xin Zhou
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China
| | - Stefan Hörtensteiner
- Institute of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zurich, 8008, Switzerland
| | - Guodong Ren
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China.
| | - Benke Kuai
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai, 200438, China.
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17
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Süssenbacher I, Menghini D, Scherzer G, Salinger K, Erhart T, Moser S, Vergeiner C, Hörtensteiner S, Kräutler B. Cryptic chlorophyll breakdown in non-senescent green Arabidopsis thaliana leaves. PHOTOSYNTHESIS RESEARCH 2019; 142:69-85. [PMID: 31172355 DOI: 10.1007/s11120-019-00649-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Chlorophyll (Chl) breakdown is a diagnostic visual process of leaf senescence, which furnishes phyllobilins (PBs) by the PAO/phyllobilin pathway. As Chl breakdown disables photosynthesis, it appears to have no role in photoactive green leaves. Here, colorless PBs were detected in green, non-senescent leaves of Arabidopsis thaliana. The PBs from the green leaves had structures entirely consistent with the PAO/phyllobilin pathway and the mutation of a single Chl catabolic enzyme completely abolished PBs with the particular modification. Hence, the PAO/phyllobilin pathway was active in the absence of visible senescence and expression of genes encoding Chl catabolic enzymes was observed in green Arabidopsis leaves. PBs accumulated to only sub-% amounts compared to the Chls present in the green leaves, excluding a substantial contribution of Chl breakdown from rapid Chl turnover associated with photosystem II repair. Indeed, Chl turnover was shown to involve a Chl a dephytylation and Chl a reconstitution cycle. However, non-recyclable pheophytin a is also liberated in the course of photosystem II repair, and is proposed here to be scavenged and degraded to the observed PBs. Hence, a cryptic form of the established pathway of Chl breakdown is indicated to play a constitutive role in photoactive leaves.
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Affiliation(s)
- Iris Süssenbacher
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Damian Menghini
- Institute of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Gerhard Scherzer
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Kathrin Salinger
- Institute of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | - Theresia Erhart
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Simone Moser
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Clemens Vergeiner
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Stefan Hörtensteiner
- Institute of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Centre of Molecular Biosciences, University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria.
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