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Zhang L, Yang C, Liu C. Revealing the significance of chlorophyll b in the moss Physcomitrium patens by knocking out two functional chlorophyllide a oxygenase. PHOTOSYNTHESIS RESEARCH 2023; 158:171-180. [PMID: 37653264 DOI: 10.1007/s11120-023-01044-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 08/11/2023] [Indexed: 09/02/2023]
Abstract
The chlorophyllide a oxygenase (CAO) plays a crucial role in the biosynthesis of chlorophyll b (Chl b). In the moss Physcomitrium patens (P. patens), two distinct gene copies, PpCAO1 and PpCAO2, are present. In this study, we investigate the differential expression of these CAOs following light exposure after a period of darkness (24 h) and demonstrate that the accumulation of Chl b is only abolished when both genes are knocked out. In the ppcao1cao2 mutant, most of the antenna proteins associated with both photosystems (PS) I and II are absent. Despite of the existence of LHCSR proteins and zeaxanthin, the mutant exhibits minimal non-photochemical quenching (NPQ) capacity. Nevertheless, the ppcao1cao2 mutant retains a certain level of pseudo-cyclic electron transport to provide photoprotection for PSI. These findings shed light on the dual dependency of Chl b synthesis on two CAOs and highlight the distinct effects of Chl b deprival on PSI and PSII core complexes in P. patens, a model species for bryophytes.
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Affiliation(s)
- Lin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Institute of Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Chunhong Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Cheng Liu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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2
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Su X, Yue X, Kong M, Xie Z, Yan J, Ma W, Wang Y, Zhao J, Zhang X, Liu M. Leaf Color Classification and Expression Analysis of Photosynthesis-Related Genes in Inbred Lines of Chinese Cabbage Displaying Minor Variations in Dark-Green Leaves. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112124. [PMID: 37299103 DOI: 10.3390/plants12112124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/20/2023] [Accepted: 05/21/2023] [Indexed: 06/12/2023]
Abstract
The leaves of the Chinese cabbage which is most widely consumed come in a wide variety of colors. Leaves that are dark green can promote photosynthesis, effectively improving crop yield, and therefore hold important application and cultivation value. In this study, we selected nine inbred lines of Chinese cabbage displaying slight differences in leaf color, and graded the leaf color using the reflectance spectra. We clarified the differences in gene sequences and the protein structure of ferrochelatase 2 (BrFC2) among the nine inbred lines, and used qRT-PCR to analyze the expression differences of photosynthesis-related genes in inbred lines with minor variations in dark-green leaves. We found expression differences among the inbred lines of Chinese cabbage in photosynthesis-related genes involved in the porphyrin and chlorophyll metabolism, as well as in photosynthesis and photosynthesis-antenna protein pathway. Chlorophyll b content was significantly positively correlated with the expression of PsbQ, LHCA1_1 and LHCB6_1, while chlorophyll a content was significantly negatively correlated with the expression PsbQ, LHCA1_1 and LHCA1_2. Our results provide an empirical basis for the precise identification of candidate genes and a better understanding of the molecular mechanisms responsible for the production of dark-green leaves in Chinese cabbage.
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Affiliation(s)
- Xiangjie Su
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Xiaonan Yue
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Mingyu Kong
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Ziwei Xie
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Jinghui Yan
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Wei Ma
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Yanhua Wang
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Jianjun Zhao
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Xiaomeng Zhang
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
| | - Mengyang Liu
- State Key Laboratory of North China Crop Improvement and Regulation, Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding 071000, China
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3
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Dey D, Tanaka R, Ito H. Structural Characterization of the Chlorophyllide a Oxygenase (CAO) Enzyme Through an In Silico Approach. J Mol Evol 2023; 91:225-235. [PMID: 36869271 DOI: 10.1007/s00239-023-10100-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 02/16/2023] [Indexed: 03/05/2023]
Abstract
Chlorophyllide a oxygenase (CAO) is responsible for converting chlorophyll a to chlorophyll b in a two-step oxygenation reaction. CAO belongs to the family of Rieske-mononuclear iron oxygenases. Although the structure and reaction mechanism of other Rieske monooxygenases have been described, a member of plant Rieske non-heme iron-dependent monooxygenase has not been structurally characterized. The enzymes in this family usually form a trimeric structure and electrons are transferred between the non-heme iron site and the Rieske center of the adjoining subunits. CAO is supposed to form a similar structural arrangement. However, in Mamiellales such as Micromonas and Ostreococcus, CAO is encoded by two genes where non-heme iron site and Rieske cluster localize on the distinct polypeptides. It is not clear if they can form a similar structural organization to achieve the enzymatic activity. In this study, the tertiary structures of CAO from the model plant Arabidopsis thaliana and the Prasinophyte Micromonas pusilla were predicted by deep learning-based methods, followed by energy minimization and subsequent stereochemical quality assessment of the predicted models. Furthermore, the chlorophyll a binding cavity and the interaction of ferredoxin, which is the electron donor, on the surface of Micromonas CAO were predicted. The electron transfer pathway was predicted in Micromonas CAO and the overall structure of the CAO active site was conserved even though it forms a heterodimeric complex. The structures presented in this study will serve as a basis for understanding the reaction mechanism and regulation of the plant monooxygenase family to which CAO belongs.
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Affiliation(s)
- Debayan Dey
- Graduate School of Life Science, Hokkaido University, N10 W8, Sapporo, 060-0810, Japan
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819, Japan
| | - Ryouichi Tanaka
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819, Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Sapporo, 060-0819, Japan.
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4
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Li D, Yu F, Zhang Y, Hu K, Dai D, Song S, Zhang F, Sa R, Lian H, Sheng Y. Integrative analysis of different low-light-tolerant cucumber lines in response to low-light stress. FRONTIERS IN PLANT SCIENCE 2023; 13:1093859. [PMID: 36743563 PMCID: PMC9891299 DOI: 10.3389/fpls.2022.1093859] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/14/2022] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Low light stress inhibits plant growth due to a line of physiological disruptions in plants, and is one of the major barriers to protected cucumber cultivation in northern China. METHODS To comprehensively understand the responses of cucumber seedlings to low-light stress, the low-light-tolerant line (M67) and The low-light-sensitive line (M14) were conducted for the analysis of photosynthetic phenotype, RNA sequencing (RNA-seq) and the expression level of photosynthesis-related genes in leaves under low-light stress and normal light condition (control). RESULTS The results showed that there was a sharp decrease in the photosynthate accumulation in the leaves of the sensitive line, M14, resulting in a large decrease in the photosynthetic rate (Pn) (with 31.99%) of leaves compared to that of the control, which may have been caused by damage to chloroplast ultrastructure or a decrease in chlorophyll (Chl) content. However, under the same low-light treatment, there was no large drop in the photosynthate accumulation and even no decrease in Pn and Chl content for the tolerant line, M67. Moreover, results of gene expression analysis showed that the expression level of genes CsPsbQ (the photosystem II oxygen-evolving enhancer protein 3 gene) and Csgamma (ATPase, F1 complex gene) in the M14 leaves decreased sharply (by 35.04% and 30.58%, respectively) compared with the levels in the M67 leaves, which decreased by 14.78% and 23.61%, respectively. The expression levels of genes involved in Chl synthesis and carbohydrate biosynthesis in the leaves of M14 decreased markedly after low-light treatment; in contrast, there were no sharp decreases or changes in leaves of M67. DISCUSSION Over all, the ability of cucumber to respond to low-light stress, as determined on the basis of the degree of damage in leaf structure and chloroplast ultrastructure, which corresponded to decreased gene expression levels and ATP phosphorylase activity, significantly differed between different low-light-tolerant lines, which was manifested as significant differences in photosynthetic capacity between them. Results of this study will be a reference for comprehensive insight into the physiological mechanism involved in the low-light tolerance of cucumber.
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Affiliation(s)
- Dandan Li
- *Correspondence: Dandan Li, ; Yunyan Sheng,
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5
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Leister D. Enhancing the light reactions of photosynthesis: Strategies, controversies, and perspectives. MOLECULAR PLANT 2023; 16:4-22. [PMID: 35996755 DOI: 10.1016/j.molp.2022.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/26/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Photosynthesis is central to life on Earth, employing sunlight, water, and carbon dioxide to produce chemical energy and oxygen. It is generally accepted that boosting its efficiency offers one promising way to increase crop yields under agronomically realistic conditions. Since the components, structure, and regulatory mechanisms of the light reactions of photosynthesis are well understood, concepts for enhancing the process have been suggested and partially tested. These approaches vary in complexity, from targeting single components to comprehensive redesign of the whole process on the scales from single cells or tissues to whole canopies. Attempts to enhance light utilization per leaf, by decreasing pigmentation, increasing levels of photosynthetic proteins, prolonging the lifespan of the photosynthetic machinery, or massive reconfiguration of the photosynthetic machinery and the incorporation of nanomaterials, are discussed in this review first. Secondly, strategies intended to optimize the acclimation of photosynthesis to changes in the environment are presented, including redesigning mechanisms to dissipate excess excitation energy (e.g., non-photochemical quenching) or reduction power (e.g., flavodiiron proteins). Moreover, schemes for improving acclimation, inspired by natural or laboratory-induced adaptation, are introduced. However, all these endeavors are still in an early exploratory phase and/or have not resulted in the desired outcome, largely because photosynthesis is embedded within large networks of closely interacting cellular and metabolic processes, which can vary among species and even cultivars. This explains why integrated, systems-wide approaches are required to achieve the breakthroughs required for effectively increasing crop yields.
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Affiliation(s)
- Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University (LMU) Munich, Martinsried-Planegg, D-82152 Munich, Germany.
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Mei X, Zhang K, Lin Y, Su H, Lin C, Chen B, Yang H, Zhang L. Metabolic and Transcriptomic Profiling Reveals Etiolated Mechanism in Huangyu Tea ( Camellia sinensis) Leaves. Int J Mol Sci 2022; 23:ijms232315044. [PMID: 36499369 PMCID: PMC9740216 DOI: 10.3390/ijms232315044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/26/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Leaf color is one of the key factors involved in determining the processing suitability of tea. It relates to differential accumulation of flavor compounds due to the different metabolic mechanisms. In recent years, photosensitive etiolation or albefaction is an interesting direction in tea research field. However, the molecular mechanism of color formation remains unclear since albino or etiolated mutants have different genetic backgrounds. In this study, wide-target metabolomic and transcriptomic analyses were used to reveal the biological mechanism of leaf etiolation for 'Huangyu', a bud mutant of 'Yinghong 9'. The results indicated that the reduction in the content of chlorophyll and the ratio of chlorophyll to carotenoids might be the biochemical reasons for the etiolation of 'Huangyu' tea leaves, while the content of zeaxanthin was significantly higher. The differentially expressed genes (DEGs) involved in chlorophyll and chloroplast biogenesis were the biomolecular reasons for the formation of green or yellow color in tea leaves. In addition, our results also revealed that the changes of DEGs involved in light-induced proteins and circadian rhythm promoted the adaptation of etiolated tea leaves to light stress. Variant colors of tea leaves indicated different directions in metabolic flux and accumulation of flavor compounds.
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Affiliation(s)
- Xin Mei
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Kaikai Zhang
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Yongen Lin
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Hongfeng Su
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Chuyuan Lin
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Baoyi Chen
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Haijun Yang
- Center for Basic Experiments and Practical Training, South China Agricultural University, Guangzhou 510642, China
- Correspondence: (H.Y.); (L.Z.); Tel.: +86-020-8528-0542 (L.Z.)
| | - Lingyun Zhang
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
- Correspondence: (H.Y.); (L.Z.); Tel.: +86-020-8528-0542 (L.Z.)
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7
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Koh E, Brandis A, Fluhr R. Plastid and cytoplasmic origins of 1O 2-mediated transcriptomic responses. FRONTIERS IN PLANT SCIENCE 2022; 13:982610. [PMID: 36420020 PMCID: PMC9676463 DOI: 10.3389/fpls.2022.982610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
The reactive oxygen species singlet oxygen, 1O2, has an extremely short half-life, yet is intimately involved with stress signalling in the cell. We previously showed that the effects of 1O2 on the transcriptome are highly correlated with 80S ribosomal arrest due to oxidation of guanosine residues in mRNA. Here, we show that dysregulation of chlorophyll biosynthesis in the flu mutant or through feeding by δ-aminolevulinic acid can lead to accumulation of photoactive chlorophyll intermediates in the cytoplasm, which generates 1O2 upon exposure to light and causes the oxidation of RNA, eliciting 1O2-responsive genes. In contrast, transcriptomes derived from DCMU treatment, or the Ch1 mutant under moderate light conditions display commonalties with each other but do not induce 1O2 gene signatures. Comparing 1O2 related transcriptomes to an index transcriptome induced by cycloheximide inhibition enables distinction between 1O2 of cytosolic or of plastid origin. These comparisons provide biological insight to cases of mutants or environmental conditions that produce 1O2.
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Affiliation(s)
- Eugene Koh
- Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander Brandis
- Life Sciences Core Facility, Weizmann Institute of Science, Rehovot, Israel
| | - Robert Fluhr
- Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
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Li L, An Q, Wang QM, Liu W, Qi X, Cui J, Wang Y, Ke H. The mechanism of bud dehyperhydricity by the method of 'starvation drying combined with AgNO3' in Lycium ruthenicum. TREE PHYSIOLOGY 2022; 42:1841-1857. [PMID: 35451030 DOI: 10.1093/treephys/tpac047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
Micropropagation is very important for rapid clonal propagation and scientific research of woody plants. However, the micropropagated materials usually show hyperhydricity, which seriously hinders application of the micropropagation. Lycium ruthenicum is an important species of eco-economic forests. Herein, treatment of 'starvation and drying combined with 30 μM AgNO3' (SDCAg+) removed serious hyperhydricity of L. ruthenicum buds regenerated from its green-inflorescence-explants, and then gene expression, metabolites of various phytohormones, chloroplasts, chlorophyll (Chl) and total soluble proteins of the hyperhydric and dehyperhydric leaves were compared and analyzed. The results suggested that the SDCAg+ treatment might remove hyperhydricity of L. ruthenicum through: reducing water uptake; increasing water loss; up-regulating the expression of chloroplast-ribosomal-protein genes from nuclear genome; down-regulating the expression of cytoplasmic-ribosomal-protein genes; up-regulating the synthesis of the total soluble proteins; restoring the lamellar structure of chloroplast grana and matrix; improving Chl synthesis and reducing Chl metabolism; increasing expression of light-harvesting Chl protein complex genes and content of Chla and b; up-regulating both photosynthesis and starch and sucrose metabolism KEGG pathways; up-regulating abscisic acid, salicylic acid and their signaling; down-regulating cytokinin, jasmonic acid, jasmonoyl-l-isoleucine and their signaling. Also, the above events interact to form a regulatory network of dehyperhydricity by SDCAg+ treatment. Overall, the study indicated key genes/pathways and physiological/subcellular changes involved in dehyperhydricity and then established a dehyperhydric mechanism model of L. ruthenicum. This not only proposed clues for preventing or removing hyperhydricity but also laid foundations for molecular breeding of L. ruthenicum and other species.
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Affiliation(s)
- Lujia Li
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Qinxia An
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Qin-Mei Wang
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Wen Liu
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Xinyu Qi
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Jianguo Cui
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Yucheng Wang
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
| | - Haifeng Ke
- Key Laboratory of Forest Tree Genetics, Breeding and Cultivation of Liaoning Province, College of Forestry, Shenyang Agricultural University, Shenyang 110866, China
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Identification of a biomass unaffected pale green mutant gene in Chinese cabbage (Brassica rapa L. ssp. pekinensis). Sci Rep 2022; 12:7731. [PMID: 35546169 PMCID: PMC9095832 DOI: 10.1038/s41598-022-11825-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/27/2022] [Indexed: 11/29/2022] Open
Abstract
Chlorophyll (Chl) is an essential component of the photosynthetic apparatus and pigments in plant greening. Leaf color is an important agronomic and commercial trait of Chinese cabbage. In this study, we identified a pale green mutant pgm created by ethyl methane sulfonate (EMS) mutagenesis in Chinese cabbage. Compared with wild-type (FT), pgm had a lower Chl content with a higher Chl a/b ratio, imperfect chloroplast structure, and lower non-photochemical quenching. However, its net photosynthetic rate and biomass showed no significant differences. Genetic analysis revealed that the pale green phenotype of pgm was controlled by a recessive nuclear gene, designated as Brpgm. We applied BSR-Seq, linkage analysis, and whole-genome resequencing to map Brpgm and predicted that the target gene was BraA10g007770.3C (BrCAO), which encodes chlorophyllide a oxygenase (CAO). Brcao sequencing results showed that the last nucleotide of its first intron changed from G to A, causing the deletion of the first nucleotide in its second CDS and termination of the protein translation. The expression of BrCAO in pgm was upregulated, and the enzyme activity of CAO in pgm was significantly decreased. These results provide an approach to explore the function of BrCAO and create a pale green variation in Chinese cabbage.
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10
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Fölsche V, Großmann C, Richter AS. Impact of Porphyrin Binding to GENOMES UNCOUPLED 4 on Tetrapyrrole Biosynthesis in planta. FRONTIERS IN PLANT SCIENCE 2022; 13:850504. [PMID: 35371166 PMCID: PMC8967248 DOI: 10.3389/fpls.2022.850504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
Plant tetrapyrrole biosynthesis (TPS) provides the indispensable chlorophyll (Chl) and heme molecules in photosynthetic organisms. Post-translational mechanisms control the enzymes to ensure a balanced flow of intermediates in the pathway and synthesis of appropriate amounts of both endproducts. One of the critical regulators of TPS is GENOMES UNCOUPLED 4 (GUN4). GUN4 interacts with magnesium chelatase (MgCh), and its binding of the catalytic substrate and product of the MgCh reaction stimulates the insertion of Mg2+ into protoporphyrin IX. Despite numerous in vitro studies, knowledge about the in vivo function of the GUN4:porphyrin interaction for the whole TPS pathway, particularly in plants, is still limited. To address this, we focused on two highly conserved amino acids crucial for porphyrin-binding to GUN4 and analyzed GUN4-F191A, R211A, and R211E substitution mutants in vitro and in vivo. Our analysis confirmed the importance of these amino acids for porphyrin-binding and the stimulation of plant MgCh by GUN4 in vitro. Expression of porphyrin-binding deficient F191A, R211A, and R211E in the Arabidopsis gun4-2 knockout mutant background revealed that, unlike in cyanobacteria and green algae, GUN4:porphyrin interactions did not affect the stability of GUN4 or other Arabidopsis TPS pathway enzymes in vivo. In addition, although they shared diminished porphyrin-binding and MgCh activation in vitro, expression of the different GUN4 mutants in gun4-2 had divergent effects on the TPS and the accumulation of Chl and Chl-binding proteins. For instance, expression of R211E, but not R211A, induced a substantial decrease of ALA synthesis rate, lower TPS intermediate and Chl level, and strongly impaired accumulation of photosynthetic complexes compared to wild-type plants. Furthermore, the presence of R211E led to significant growth retardation and paler leaves compared to GUN4 knockdown mutants, indicating that the exchange of R211 to glutamate compromised TPS and Chl accumulation more substantially than the almost complete lack of GUN4. Extensive in vivo analysis of GUN4 point mutants suggested that F191 and R211 might also play a role beyond porphyrin-binding.
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Affiliation(s)
- Vincent Fölsche
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
- Department of Plant Physiology, Humboldt-Universität Berlin, Berlin, Germany
| | - Christopher Großmann
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
| | - Andreas S. Richter
- Physiology of Plant Cell Organelles, Humboldt-Universität Berlin, Berlin, Germany
- Department of Plant Physiology, Humboldt-Universität Berlin, Berlin, Germany
- Physiology of Plant Metabolism, University of Rostock, Rostock, Germany
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11
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Dogra V, Singh RM, Li M, Li M, Singh S, Kim C. EXECUTER2 modulates the EXECUTER1 signalosome through its singlet oxygen-dependent oxidation. MOLECULAR PLANT 2022; 15:438-453. [PMID: 34968736 DOI: 10.1016/j.molp.2021.12.016] [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: 02/11/2021] [Revised: 11/29/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
Oxidative post-translational modifications of specific chloroplast proteins contribute to the initiation of retrograde signaling. The Arabidopsis thaliana EXECUTER1 (EX1) protein, a chloroplast-localized singlet oxygen (1O2) sensor, undergoes tryptophan (Trp) 643 oxidation by 1O2, a chloroplast-derived and light-dependent reactive oxygen species. The indole side chain of Trp is vulnerable to 1O2, leading to the generation of oxidized Trp variants and priming EX1 for degradation by a membrane-bound FtsH protease. The perception of 1O2 via Trp643 oxidation and subsequent EX1 proteolysis facilitate chloroplast-to-nucleus retrograde signaling. In this study, we discovered that the EX1-like protein EX2 also undergoes 1O2-dependent Trp530 oxidation and FtsH-dependent turnover, which attenuates 1O2 signaling by decelerating EX1-Trp643 oxidation and subsequent EX1 degradation. Consistent with this finding, the loss of EX2 function reinforces EX1-dependent retrograde signaling by accelerating EX1-Trp643 oxidation and subsequent EX1 proteolysis, whereas overexpression of EX2 produces molecular phenotypes opposite to those observed in the loss-of- function mutants of EX2. Intriguingly, phylogenetic analysis suggests that EX2 may have emerged evolutionarily to attenuate the sensitivity of EX1 toward 1O2. Collectively, these results suggest that EX2 functions as a negative regulator of the EX1 signalosome through its own 1O2-dependent oxidation, providing a new mechanistic insight into the regulation of EX1-mediated 1O2 signaling.
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Affiliation(s)
- Vivek Dogra
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Rahul Mohan Singh
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Mengping Li
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Mingyue Li
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China; University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Somesh Singh
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
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12
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Sattari Vayghan H, Nawrocki WJ, Schiphorst C, Tolleter D, Hu C, Douet V, Glauser G, Finazzi G, Croce R, Wientjes E, Longoni F. Photosynthetic Light Harvesting and Thylakoid Organization in a CRISPR/Cas9 Arabidopsis Thaliana LHCB1 Knockout Mutant. FRONTIERS IN PLANT SCIENCE 2022; 13:833032. [PMID: 35330875 PMCID: PMC8940271 DOI: 10.3389/fpls.2022.833032] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
Light absorbed by chlorophylls of Photosystems II and I drives oxygenic photosynthesis. Light-harvesting complexes increase the absorption cross-section of these photosystems. Furthermore, these complexes play a central role in photoprotection by dissipating the excess of absorbed light energy in an inducible and regulated fashion. In higher plants, the main light-harvesting complex is trimeric LHCII. In this work, we used CRISPR/Cas9 to knockout the five genes encoding LHCB1, which is the major component of LHCII. In absence of LHCB1, the accumulation of the other LHCII isoforms was only slightly increased, thereby resulting in chlorophyll loss, leading to a pale green phenotype and growth delay. The Photosystem II absorption cross-section was smaller, while the Photosystem I absorption cross-section was unaffected. This altered the chlorophyll repartition between the two photosystems, favoring Photosystem I excitation. The equilibrium of the photosynthetic electron transport was partially maintained by lower Photosystem I over Photosystem II reaction center ratio and by the dephosphorylation of LHCII and Photosystem II. Loss of LHCB1 altered the thylakoid structure, with less membrane layers per grana stack and reduced grana width. Stable LHCB1 knockout lines allow characterizing the role of this protein in light harvesting and acclimation and pave the way for future in vivo mutational analyses of LHCII.
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Affiliation(s)
- Hamed Sattari Vayghan
- Laboratory of Plant Physiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Wojciech J. Nawrocki
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Christo Schiphorst
- Laboratory of Biophysics, Wageningen University, Wageningen, Netherlands
| | - Dimitri Tolleter
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, Grenoble, France
| | - Chen Hu
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Véronique Douet
- Laboratory of Plant Physiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Gaëtan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Giovanni Finazzi
- Univ. Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, Grenoble, France
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University, Wageningen, Netherlands
| | - Fiamma Longoni
- Laboratory of Plant Physiology, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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13
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Bhatt M, Pandey SS, Tiwari AK, Tiwari BS. Plastid-mediated singlet oxygen in regulated cell death. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:686-694. [PMID: 33768665 DOI: 10.1111/plb.13260] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Reactive oxygen species (ROS) generation within a cell is a natural process of specific subcellular components involved in redox reactions. Within a plant cell, chloroplasts are one of the major sources of ROS generation. Plastid-generated ROS molecules include singlet oxygen (1 O2 ), superoxide radical (O2 - ), hydroxyl radical (OH• ) and hydrogen peroxide (H2 O2 ), which are produced mainly during photochemical reactions of photosynthesis and chlorophyll biosynthetic process. Under normal growth and developmental, generated ROS molecules act as a secondary messenger controlling several metabolic reactions; however, perturbed environmental conditions lead to multi-fold amplification of cellular ROS that eventually kill the target cell. To maintain homeostasis between production and scavenging of ROS, the cell has instituted several enzymatic and non-enzymatic antioxidant machineries to maintain ROS at a physiological level. Among chloroplastic ROS molecules, excess generation of singlet oxygen (1 O2 ) is highly deleterious to the cell metabolic functions and survival. Interestingly, within cellular antioxidant machinery, enzymes involved in detoxification of 1 O2 are lacking. Recent studies suggest that under optimal concentrations, 1 O2 acts as a signalling molecule and drives the cell to either the acclimation pathway or regulated cell death (RCD). Stress-induced RCD is a survival mechanism for the whole plant, while the involvement of chloroplasts and chloroplast-localized molecules that execute RCD are not well understood. In this review, we advocate for participation of chloroplasts-generated 1 O2 in signalling and RCD in plants.
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Affiliation(s)
- M Bhatt
- Institute of Advanced Research, Gandhinagar, Gujrat, India
| | - S S Pandey
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, H.P., India
| | - A K Tiwari
- Institute of Advanced Research, Gandhinagar, Gujrat, India
| | - B S Tiwari
- Institute of Advanced Research, Gandhinagar, Gujrat, India
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14
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Jung YJ, Lee HJ, Yu J, Bae S, Cho YG, Kang KK. Transcriptomic and physiological analysis of OsCAO1 knockout lines using the CRISPR/Cas9 system in rice. PLANT CELL REPORTS 2021; 40:1013-1024. [PMID: 32980909 DOI: 10.1007/s00299-020-02607-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
The altered rice leaf color based on the knockout of CAO1 gene generated using CRISPR/Cas9 technology plays important roles in chlorophyll degradation and ROS scavenging to regulate both natural and induced senescence in rice. Rice chlorophyllide a oxygenase (OsCAO1), identified as the chlorophyll b synthesis under light condition, plays a critical role in regulating rice plant photosynthesis. In this study, the development of edited lines with pale green leaves by knockout of OsCAO1 gene known as a chlorophyll synthesis process is reported. Eighty-one genetically edited lines out of 181 T0 plants were generated through CRISPR/Cas9 system. The edited lines have short narrow flag leaves and pale green leaves compared with wild-type 'Dongjin' plants (WT). Additionally, edited lines have lower chlorophyll b and carotenoid contents both at seedling and mature stages. A transcriptome analysis identified 580 up-regulated and 206 downregulated genes in the edited lines. The differentially expressed genes (DEGs) involved in chlorophyll biosynthesis, magnesium chelatase subunit (CHLH), and glutamate-1-semialdehyde2, 1-aminomutase (GSA) metabolism decreased significantly. Meanwhile, the gel consistency (GC) levels of rice grains, chalkiness ratios and chalkiness degrees (CD) decreased in the edited lines. Thus, knockout of OsCAO1 influenced growth period, leaf development and grain quality characters of rice. Overall, the result suggests that OsCAO1 also plays important roles in chlorophyll degradation and ROS scavenging to regulate both natural and induced rice senescence.
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Affiliation(s)
- Yu Jin Jung
- Division of Horticultural Biotechnology, Hankyong National University, Anseong, 17579, South Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong, 17579, South Korea
| | - Hyo Ju Lee
- Division of Horticultural Biotechnology, Hankyong National University, Anseong, 17579, South Korea
| | - Jihyeon Yu
- Department of Chemistry, Hanyang University, Seoul, 04763, South Korea
| | - Sangsu Bae
- Department of Chemistry, Hanyang University, Seoul, 04763, South Korea
| | - Yong-Gu Cho
- Department of Crop Science, Chungbuk National University, Cheongju, 28644, South Korea
| | - Kwon Kyoo Kang
- Division of Horticultural Biotechnology, Hankyong National University, Anseong, 17579, South Korea.
- Institute of Genetic Engineering, Hankyong National University, Anseong, 17579, South Korea.
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15
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Solymosi K, Mysliwa-Kurdziel B. The Role of Membranes and Lipid-Protein Interactions in the Mg-Branch of Tetrapyrrole Biosynthesis. FRONTIERS IN PLANT SCIENCE 2021; 12:663309. [PMID: 33995458 PMCID: PMC8113382 DOI: 10.3389/fpls.2021.663309] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/22/2021] [Indexed: 05/31/2023]
Abstract
Chlorophyll (Chl) is essential for photosynthesis and needs to be produced throughout the whole plant life, especially under changing light intensity and stress conditions which may result in the destruction and elimination of these pigments. All steps of the Mg-branch of tetrapyrrole biosynthesis leading to Chl formation are carried out by enzymes associated with plastid membranes. Still the significance of these protein-membrane and protein-lipid interactions in Chl synthesis and chloroplast differentiation are not very well-understood. In this review, we provide an overview on Chl biosynthesis in angiosperms with emphasis on its association with membranes and lipids. Moreover, the last steps of the pathway including the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), the biosynthesis of the isoprenoid phytyl moiety and the esterification of Chlide are also summarized. The unique biochemical and photophysical properties of the light-dependent NADPH:protochlorophyllide oxidoreductase (LPOR) enzyme catalyzing Pchlide photoreduction and located to peculiar tubuloreticular prolamellar body (PLB) membranes of light-deprived tissues of angiosperms and to envelope membranes, as well as to thylakoids (especially grana margins) are also reviewed. Data about the factors influencing tubuloreticular membrane formation within cells, the spectroscopic properties and the in vitro reconstitution of the native LPOR enzyme complexes are also critically discussed.
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Affiliation(s)
- Katalin Solymosi
- Department of Plant Anatomy, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Beata Mysliwa-Kurdziel
- Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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16
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Li Q, Zhou S, Liu W, Zhai Z, Pan Y, Liu C, Chern M, Wang H, Huang M, Zhang Z, Tang J, Du H. A chlorophyll a oxygenase 1 gene ZmCAO1 contributes to grain yield and waterlogging tolerance in maize. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3155-3167. [PMID: 33571996 DOI: 10.1093/jxb/erab059] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 02/07/2021] [Indexed: 05/16/2023]
Abstract
Chlorophylls function in photosynthesis, and are critical to plant developmental processes and responses to environmental stimuli. Chlorophyll b is synthesized from chlorophyll a by chlorophyll a oxygenase (CAO). Here, we characterize a yellow-green leaf (ygl) mutant and identify the causal gene which encodes a chlorophyll a oxygenase in maize (ZmCAO1). A 51 bp Popin transposon insertion in ZmCAO1 strongly disrupts its transcription. Low enzyme activity of ZmCAO1 leads to reduced concentrations of chlorophyll a and chlorophyll b, resulting in the yellow-green leaf phenotype of the ygl mutant. The net photosynthetic rate, stomatal conductance, and transpiration rate are decreased in the ygl mutant, while concentrations of δ-aminolevulinic acid (ALA), porphobilinogen (PBG) and protochlorophyllide (Pchlide) are increased. In addition, a ZmCAO1 mutation results in down-regulation of key photosynthetic genes, limits photosynthetic assimilation, and reduces plant height, ear size, kernel weight, and grain yield. Furthermore, the zmcao1 mutant shows enhanced reactive oxygen species production leading to sensitivity to waterlogging. These results demonstrate the pleiotropy of ZmCAO1 function in photosynthesis, grain yield, and waterlogging tolerance in maize.
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Affiliation(s)
- Qin Li
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Shuangzhen Zhou
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Wenyu Liu
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Zhensheng Zhai
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Yitian Pan
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Changchang Liu
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Mawsheng Chern
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616,USA
| | - Hongwei Wang
- Hubei Collaborative Innovation Center for Grain Crops, Yangzte University, Jingzhou 434025, P.R. China
| | - Min Huang
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
| | - Zuxin Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070,P.R.China
| | - Jihua Tang
- College of Agronomy, Henan Agricultural University, Zhengzhou, Henan, 450046,P.R.China
| | - Hewei Du
- College of Life Science, Yangtze University, Jingzhou, Hubei 434025, P.R.China
- Hubei Collaborative Innovation Center for Grain Crops, Yangzte University, Jingzhou 434025, P.R. China
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17
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Agrawal R, Jiří F, Thakur JK. The kinase module of the Mediator complex: an important signalling processor for the development and survival of plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:224-240. [PMID: 32945869 DOI: 10.1093/jxb/eraa439] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 09/16/2020] [Indexed: 05/06/2023]
Abstract
Mediator, a multisubunit protein complex, is a signal processor that conveys regulatory information from transcription factors to RNA polymerase II and therefore plays an important role in the regulation of gene expression. This megadalton complex comprises four modules, namely, the head, middle, tail, and kinase modules. The first three modules form the core part of the complex, whereas association of the kinase module is facultative. The kinase module is able to alter the function of Mediator and has been established as a major transcriptional regulator of numerous developmental and biochemical processes. The kinase module consists of MED12, MED13, CycC, and kinase CDK8. Upon association with Mediator, the kinase module can alter its structure and function dramatically. In the past decade, research has established that the kinase module is very important for plant growth and development, and in the fight against biotic and abiotic challenges. However, there has been no comprehensive review discussing these findings in detail and depth. In this review, we survey the regulation of kinase module subunits and highlight their many functions in plants. Coordination between the subunits to process different signals for optimum plant growth and development is also discussed.
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Affiliation(s)
- Rekha Agrawal
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Fajkus Jiří
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jitendra K Thakur
- Plant Mediator Lab, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
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18
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Li JY, Sun JL, Tian YY, Liu JX. The FtsH-Inactive Protein FtsHi5 Is Required for Chloroplast Development and Protein Accumulation in Chloroplasts at Low Ambient Temperature in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2021; 12:830390. [PMID: 35185971 PMCID: PMC8850778 DOI: 10.3389/fpls.2021.830390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/29/2021] [Indexed: 05/03/2023]
Abstract
Chloroplasts are indispensable for higher plants. The growth and development of plants are very sensitive to environmental temperature changes, and chloroplast development is also regulated by adverse environmental temperatures. However, the molecular mechanism of how plants coordinate chloroplast development and environmental temperature changes remains largely unknown. Here, a temperature-conditioned chloroplast development defective mutant thermo-sensitive mutant in leaf color 2 (tsl2) of Arabidopsis was obtained through a forward genetic screening. The tsl2 mutant showed a weak yellowish phenotype at normal growth temperature (22°C), and the phenotype was more pronounced at low growth temperature (16°C) and largely rescued at high growth temperature (29°C). Bulk Segregant Analysis (BSA) revealed that TSL2 encodes FtsH-Inactive Protein 5 (FtsHi5). Genetic complementation analysis confirmed that complemented expression of FtsHi5 rescued the chlorophyll content and thylakoid development defects observed in tsl2 mutants at 16°C. Quantitative mass spectrometry analysis with Tandem Mass Tag (TMT) isobaric labeling revealed broad changes in the chloroplast proteome of tsl2 mutant plants at low temperature, which is agreed with the impaired chloroplast biogenesis and function in tsl2 plants. Together, our data demonstrates that FtsHi5/TSL2 plays an important role in chloroplast development and protein accumulation in chloroplasts, especially at low environmental temperatures in Arabidopsis.
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Affiliation(s)
- Jin-Yu Li
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jing-Liang Sun
- College of Environment and Resources, Dalian Nationalities University, Dalian, China
| | - Ying-Ying Tian
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jian-Xiang Liu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
- *Correspondence: Jian-Xiang Liu,
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19
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Compensation Mechanism of the Photosynthetic Apparatus in Arabidopsis thaliana ch1 Mutants. Int J Mol Sci 2020; 22:ijms22010221. [PMID: 33379339 PMCID: PMC7794896 DOI: 10.3390/ijms22010221] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 12/17/2020] [Accepted: 12/23/2020] [Indexed: 11/17/2022] Open
Abstract
The origin of chlorophyll b deficiency is a mutation (ch1) in chlorophyllide a oxygenase (CAO), the enzyme responsible for Chl b synthesis. Regulation of Chl b synthesis is essential for understanding the mechanism of plant acclimation to various conditions. Therefore, the main aim of this study was to find the strategy in plants for compensation of low chlorophyll content by characterizing and comparing the performance and spectral properties of the photosynthetic apparatus related to the lipid and protein composition in four selected Arabidopsis ch1 mutants and two Arabidopsis ecotypes. Mutation in different loci of the CAO gene, viz., NW41, ch1.1, ch1.2 and ch1.3, manifested itself in a distinct chlorina phenotype, pigment and photosynthetic protein composition. Changes in the CAO mRNA levels and chlorophyllide a (Chlide a) content in ecotypes and ch1 mutants indicated their significant role in the adjustment mechanism of the photosynthetic apparatus to low-light conditions. Exposure of mutants with a lower chlorophyll b content to short-term (1LL) and long-term low-light stress (10LL) enabled showing a shift in the structure of the PSI and PSII complexes via spectral analysis and the thylakoid composition studies. We demonstrated that both ecotypes, Col-1 and Ler-0, reacted to high-light (HL) conditions in a way remarkably resembling the response of ch1 mutants to normal (NL) conditions. We also presented possible ways of regulating the conversion of chlorophyll a to b depending on the type of light stress conditions.
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20
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Zhao X, Jia T, Hu X. HCAR Is a Limitation Factor for Chlorophyll Cycle and Chlorophyll b Degradation in Chlorophyll- b-Overproducing Plants. Biomolecules 2020; 10:E1639. [PMID: 33291365 PMCID: PMC7762049 DOI: 10.3390/biom10121639] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/25/2020] [Accepted: 12/02/2020] [Indexed: 11/17/2022] Open
Abstract
The chlorophyll (Chl) cycle is the metabolic pathway for Chl a and Chl b inter-conversion. In this pathway, Chl b is synthesized from Chl a by the catalyzing action of chlorophyllide a oxygenase (CAO). In contrast, Chl b is firstly reduced to produce 7-hydroxymethyl Chl (HMChl) a, which is catalyzed by two isozymes of Chl b reductase (CBR), non-yellow coloring 1 (NYC1) and NYC1-like (NOL). Subsequently, HMChl a is reduced to Chl a by HMChl a reductase (HCAR). CAO plays a pivotal role in Chl a/b ratio regulation and plants over-accumulate Chl b in CAO-overexpressing plants. NYC1 is more accumulated in Chl-b-overproducing plants, while HCAR is not changed. To investigate the role of HCAR in Chl cycle regulation, the Chl metabolites of Chl-b-overproducing plants were analyzed. The results showed that HMChl a accumulated in these plants, and it decreased and the Chl a/b ratio increased by overexpressing HCAR, implying HCAR is insufficient for Chl cycle in Chl-b-overproducing plants. Furthermore, during dark-induced senescence, the non-programmed cell death symptoms (leaves dehydrated with green color retained) of Chl-b-overproducing plants were obviously alleviated, and the content of HM pheophorbide (HMPheide) a and Pheide b were sharply decreased by overexpressing HCAR. These results imply that HCAR is also insufficient for Chl degradation in Chl-b-overproducing plants during senescence, thus causing the accumulation of Chl metabolites and non-programmed cell death of leaves. With these results taken together, we conclude that HCAR is not well regulated and it is a limiting factor for Chl cycle and Chl b degradation in Chl-b-overproducing plants.
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Affiliation(s)
- Xuan Zhao
- Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China; (X.Z.); (T.J.)
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Ting Jia
- Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China; (X.Z.); (T.J.)
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Xueyun Hu
- Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, China; (X.Z.); (T.J.)
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
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21
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Bru P, Nanda S, Malnoë A. A Genetic Screen to Identify New Molecular Players Involved in Photoprotection qH in Arabidopsis thaliana. PLANTS 2020; 9:plants9111565. [PMID: 33202829 PMCID: PMC7696684 DOI: 10.3390/plants9111565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/30/2020] [Accepted: 11/11/2020] [Indexed: 12/23/2022]
Abstract
Photosynthesis is a biological process which converts light energy into chemical energy that is used in the Calvin-Benson cycle to produce organic compounds. An excess of light can induce damage to the photosynthetic machinery. Therefore, plants have evolved photoprotective mechanisms such as non-photochemical quenching (NPQ). To focus molecular insights on slowly relaxing NPQ processes in Arabidopsis thaliana, previously, a qE-deficient line-the PsbS mutant-was mutagenized and a mutant with high and slowly relaxing NPQ was isolated. The mutated gene was named suppressor of quenching 1, or SOQ1, to describe its function. Indeed, when present, SOQ1 negatively regulates or suppresses a form of antenna NPQ that is slow to relax and is photoprotective. We have now termed this component qH and identified the plastid lipocalin, LCNP, as the effector for this energy dissipation mode to occur. Recently, we found that the relaxation of qH1, ROQH1, protein is required to turn off qH. The aim of this study is to identify new molecular players involved in photoprotection qH by a whole genome sequencing approach of chemically mutagenized Arabidopsis thaliana. We conducted an EMS-mutagenesis on the soq1 npq4 double mutant and used chlorophyll fluorescence imaging to screen for suppressors and enhancers of qH. Out of 22,000 mutagenized plants screened, the molecular players cited above were found using a mapping-by-sequencing approach. Here, we describe the phenotypic characterization of the other mutants isolated from this genetic screen and an additional 8000 plants screened. We have classified them in several classes based on their fluorescence parameters, NPQ kinetics, and pigment content. A high-throughput whole genome sequencing approach on 65 mutants will identify the causal mutations thanks to allelic mutations from having reached saturation of the genetic screen. The candidate genes could be involved in the formation or maintenance of quenching sites for qH, in the regulation of qH at the transcriptional level, or be part of the quenching site itself.
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Wang M, Zhu X, Li Y, Xia Z. Transcriptome analysis of a new maize albino mutant reveals that zeta-carotene desaturase is involved in chloroplast development and retrograde signaling. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 156:407-419. [PMID: 33010551 DOI: 10.1016/j.plaphy.2020.09.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 09/21/2020] [Indexed: 05/24/2023]
Abstract
Carotenoids are a group of natural tetraterpenoid pigments with essential roles in a variety of physiological processes of plants. Although carotenoid biosynthesis has been well characterized, the genetic basis of the pathway, especially in crop plants, is largely unknown. In this study, we characterized a new albino maize mutant called albino1 (alb1), which was obtained from a Mutator mutagenized population. The alb1 mutant showed defective chloroplast development and declined photosynthetic pigments, leading to a seedling-lethal phenotype. Genetic and molecular analyses indicated that ALB1 encoded a putative ζ-carotene desaturase (ZDS) involved in carotenoid biosynthesis. Measurement of carotenoids revealed that several major carotenoid compounds downstream of the ZDS were significantly reduced in alb1 mutant, indicating that ALB1 is a functional ZDS. Further transcriptome analysis revealed that several groups of nuclear genes involved in photosynthesis, such as light-harvesting complex, pigment metabolism, and chloroplast function, were significantly down-regulated in alb1 compared with wide type. Interestingly, expression of some maize plastid-localized nuclear genes, including POR, CAO, Lhcb, and RbcS, was substantially reduced in alb1 plants. Furthermore, treatment of the inhibitor fluridone significantly rescued gene transcripts of these nucleus-encoded genes in alb1 mutant, which supported the retrograde signaling of ζ-carotene/phytofluene derived molecules. These results suggested that ALB1/ZDS might function as a regulator to coordinate nuclear photosynthetic gene expression in plastid-to-nucleus retrograde signaling during development of maize plants. Together, these results have demonstrated that ALB1/ZDS is essential for carotenoids biosynthesis and plays crucial roles in chloroplast biogenesis and development in maize.
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Affiliation(s)
- Meiping Wang
- College of Life Science, Henan Agricultural University, Zhengzhou, 450002, PR China; Department of Information, Library of Henan Agricultural University, Zhengzhou, 450002, PR China
| | - Xianfeng Zhu
- School of Life Sciences, Henan University, Kaifeng, 475004, PR China
| | - Yu Li
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, 450002, PR China.
| | - Zongliang Xia
- College of Life Science, Henan Agricultural University, Zhengzhou, 450002, PR China; Synergetic Innovation Center of Henan Grain Crops and State Key Laboratory of Wheat & Maize Crop Science, Zhengzhou, 450002, PR China.
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Alkimin GDD, Santos J, Soares AMVM, Nunes B. Ecotoxicological effects of the azole antifungal agent clotrimazole on the macrophyte species Lemna minor and Lemna gibba. Comp Biochem Physiol C Toxicol Pharmacol 2020; 237:108835. [PMID: 32585366 DOI: 10.1016/j.cbpc.2020.108835] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/16/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
Abstract
Pharmaceuticals are a large and diverse group of compounds used to treat, prevent and diagnose disease. Among these, a group that has been recently detected in the aquatic environment is that of the azole compounds, commonly used as antifungals. Clotrimazole (CLO) is a nonbiodegradable persistent azole compound, with broad-spectrum antifungal activity for which virtually no toxicological data are available, especially towards aquatic plants. The few existent data point to a documented interference with cytochrome P450 system of exposed organisms. Therefore, the aim of this paper was to evaluate the ecotoxicological effects of the fungicide CLO on two aquatic macrophyte species, namely, Lemna minor and Lemna gibba. To attain this purpose, an acute assay (96 h) was performed with both species being exposed to CLO, in a concentration range of 0 to 5 μg L-1. The analyzed endpoints were levels of chlorophyll a and b, total, carotenoids, catalase (CAT) and glutathione -s-transferases activities (GSTs). In general, CLO exposure caused some minor alterations in L. minor and L. gibba pigment contents. Antioxidant enzymes exhibited a different pattern in both species, since the highest concentrations of CLO caused an increase on CAT activity, and a decrease on GSTs activity in L. minor, and the opposite in L. gibba, reflected by a decrease on CAT activity and an increase on GSTs activity in all tested concentrations. These results demonstrate that CLO exposure resulted in potential deleterious effects on macrophytes, namely with the involvement of the antioxidant defense mechanisms that were likely deployed to cope with pro-oxidative conditions established by CLO.
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Affiliation(s)
- Gilberto Dias de Alkimin
- Department of Biology, Aveiro University, Campus de Santiago, 3810-193 Aveiro, Portugal; Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
| | - João Santos
- Department of Biology, Aveiro University, Campus de Santiago, 3810-193 Aveiro, Portugal
| | - Amadeu M V M Soares
- Department of Biology, Aveiro University, Campus de Santiago, 3810-193 Aveiro, Portugal; Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - Bruno Nunes
- Department of Biology, Aveiro University, Campus de Santiago, 3810-193 Aveiro, Portugal; Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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Alkimin GD, Soares AMVM, Barata C, Nunes B. Can salicylic acid modulate biochemical, physiological and population alterations in a macrophyte species under chemical stress by diclofenac? THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:139715. [PMID: 32534307 DOI: 10.1016/j.scitotenv.2020.139715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/23/2020] [Accepted: 05/24/2020] [Indexed: 06/11/2023]
Abstract
Salicylic acid (SA) is a pharmaceutical drug that may exert toxic effects by its own; however, simultaneous exposure of plants to SA and to other substances, often results in the significant changes in the patterns of toxic response/resistance to these other sources of chemical stress. Thus, the aim of this work was to investigate the capacity of SA of modulating Lemna minor responses co-exposed to the pharmaceutical drug, diclofenac - DCF. To attain this objective, L. minor was exposed for 7 days, to DCF alone, and to combinations of DCF with SA. After exposure, biochemical, physiological and population endpoints were analyzed as follows: catalase (CAT) and glutathione S-transferases (GSTs) activities, pigments content (chlorophyll a (Chl a), b (Chl b) and total (TChl), carotenoids (Car) and [Chl a]/[Chl b] and [TChl]/[Car] ratios), and growth specific rate, fresh weight and root length. Single exposures to DCF were capable of causing effects in all analyzed endpoints. However, co-exposure of DCF with SA partially reverted these effects. Finally, we may suggest that SA is capable to prevent the toxicity of DCF in macrophytes, by modulating the toxic response of exposed plants.
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Affiliation(s)
- G D Alkimin
- Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
| | - A M V M Soares
- Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal
| | - C Barata
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain
| | - B Nunes
- Centre for Environmental and Marine Studies (CESAM), Campus de Santiago, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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25
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Wei X, Nguyen STT, Collings DA, McCurdy DW. Sucrose regulates wall ingrowth deposition in phloem parenchyma transfer cells in Arabidopsis via affecting phloem loading activity. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4690-4702. [PMID: 32433727 DOI: 10.1093/jxb/eraa246] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/15/2020] [Indexed: 05/27/2023]
Abstract
In Arabidopsis thaliana, phloem parenchyma transfer cells (PPTCs) occur in leaf minor veins and play a pivotal role in phloem loading. Wall ingrowth formation in PPTCs is induced by the phloem loading activity of these cells, which is regulated by sucrose (Suc). The effects of endogenous versus exogenous Suc on wall ingrowth deposition, however, differ. Elevating endogenous Suc levels by increased light enhanced wall ingrowth formation, whereas lowering endogenous Suc levels by dark treatment or genetically in ch-1 resulted in lower levels of deposition. In contrast, exogenously applied Suc, or Suc derived from other organs, repressed wall ingrowth deposition. Analysis of pAtSUC2::GFP plants, used as a marker for phloem loading status, suggested that wall ingrowth formation is correlated with phloem loading activity. Gene expression analysis revealed that exogenous Suc down-regulated expression of AtSWEET11 and 12, whereas endogenous Suc up-regulated AtSWEET11 expression. Analysis of a TREHALOSE 6-PHOSPHATE (T6P) SYNTHASE overexpression line and the hexokinase (HXK)-null mutant, gin2-1, suggested that Suc signalling of wall ingrowth formation is independent of T6P and HXK. Collectively, these results are consistent with the conclusion that Suc regulates wall ingrowth formation via affecting Suc exporting activity in PPTCs.
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Affiliation(s)
- Xiaoyang Wei
- Centre for Plant Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan NSW, Australia
| | - Suong T T Nguyen
- Centre for Plant Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan NSW, Australia
| | - David A Collings
- Centre for Plant Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan NSW, Australia
| | - David W McCurdy
- Centre for Plant Sciences, School of Environmental and Life Sciences, University of Newcastle, Callaghan NSW, Australia
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26
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Amstutz CL, Fristedt R, Schultink A, Merchant SS, Niyogi KK, Malnoë A. An atypical short-chain dehydrogenase-reductase functions in the relaxation of photoprotective qH in Arabidopsis. NATURE PLANTS 2020; 6:154-166. [PMID: 32055052 PMCID: PMC7288749 DOI: 10.1038/s41477-020-0591-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 12/28/2019] [Indexed: 05/20/2023]
Abstract
Photosynthetic organisms experience wide fluctuations in light intensity and regulate light harvesting accordingly to prevent damage from excess energy. The antenna quenching component qH is a sustained form of energy dissipation that protects the photosynthetic apparatus under stress conditions. This photoprotective mechanism requires the plastid lipocalin LCNP and is prevented by SUPPRESSOR OF QUENCHING1 (SOQ1) under non-stress conditions. However, the molecular mechanism of qH relaxation has yet to be resolved. Here, we isolated and characterized RELAXATION OF QH1 (ROQH1), an atypical short-chain dehydrogenase-reductase that functions as a qH-relaxation factor in Arabidopsis. The ROQH1 gene belongs to the GreenCut2 inventory specific to photosynthetic organisms, and the ROQH1 protein localizes to the chloroplast stroma lamellae membrane. After a cold and high-light treatment, qH does not relax in roqh1 mutants and qH does not occur in leaves overexpressing ROQH1. When the soq1 and roqh1 mutations are combined, qH can neither be prevented nor relaxed and soq1 roqh1 displays constitutive qH and light-limited growth. We propose that LCNP and ROQH1 perform dosage-dependent, antagonistic functions to protect the photosynthetic apparatus and maintain light-harvesting efficiency in plants.
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Affiliation(s)
- Cynthia L Amstutz
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Rikard Fristedt
- Department of Physics and Astronomy, Vrije University of Amsterdam, Amsterdam, The Netherlands
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Alex Schultink
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Sabeeha S Merchant
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Krishna K Niyogi
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Alizée Malnoë
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA.
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
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Responses of unicellular predators to cope with the phototoxicity of photosynthetic prey. Nat Commun 2019; 10:5606. [PMID: 31811209 PMCID: PMC6898599 DOI: 10.1038/s41467-019-13568-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/14/2019] [Indexed: 12/22/2022] Open
Abstract
Feeding on unicellular photosynthetic organisms by unicellular eukaryotes is the base of the aquatic food chain and evolutionarily led to the establishment of photosynthetic endosymbionts/organelles. Photosynthesis generates reactive oxygen species and damages cells; thus, photosynthetic organisms possess several mechanisms to cope with the stress. Here, we demonstrate that photosynthetic prey also exposes unicellular amoebozoan and excavates predators to photosynthetic oxidative stress. Upon illumination, there is a commonality in transcriptomic changes among evolutionarily distant organisms feeding on photosynthetic prey. One of the genes commonly upregulated is a horizontally transferred homolog of algal and plant genes for chlorophyll degradation/detoxification. In addition, the predators reduce their phagocytic uptake while accelerating digestion of photosynthetic prey upon illumination, reducing the number of photosynthetic cells inside the predator cells, as this also occurs in facultative endosymbiotic associations upon certain stresses. Thus, some mechanisms in predators observed here probably have been necessary for evolution of endosymbiotic associations. Photosynthesis generates reactive oxygen species that can damage cells. Here, the authors show that unicellular predators of photosynthetic prey have shared responses to photosynthetic oxidative stress and these may also have been important for the evolution of endosymbiosis.
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Nicol L, Nawrocki WJ, Croce R. Disentangling the sites of non-photochemical quenching in vascular plants. NATURE PLANTS 2019; 5:1177-1183. [PMID: 31659240 PMCID: PMC6861128 DOI: 10.1038/s41477-019-0526-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 09/05/2019] [Indexed: 05/21/2023]
Abstract
In nature, plants experience large fluctuations in light intensity and they need to balance the absorption and utilization of this energy appropriately. Non-photochemical quenching (NPQ) is a rapidly switchable mechanism that protects plants from photodamage caused by high light exposure by dissipating the excess absorbed energy as heat. It is triggered by the pH gradient across the thylakoid membrane and requires the protein PsbS and the xanthophyll zeaxanthin. However, the site and mechanism of the quencher(s) remain unknown. Here, we constructed a mutant of Arabidopsis thaliana that lacks light-harvesting complex II (LHCII), the main antenna complex of plants, to verify its contribution to NPQ. The mutant plant has normally stacked thylakoid membranes, displays no upregulation of other LHCs but shows a relative decrease in Photosystem I (PSI), which compensates for the decrease of the PSII antenna. The mutant plant exhibits a reduction in NPQ of about 60% and the remaining NPQ resembles that of mutant plants lacking chlorophyll (Chl) b, which lack all PSII peripheral antenna complexes. We thus report that PsbS-dependent NPQ occurs mainly in LHCII, but there is an additional quenching site in the PSII core.
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Affiliation(s)
- Lauren Nicol
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Wojciech J Nawrocki
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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29
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Ding J, Zhao J, Pan T, Xi L, Zhang J, Zou Z. Comparative Transcriptome Analysis of Gene Expression Patterns in Tomato Under Dynamic Light Conditions. Genes (Basel) 2019; 10:genes10090662. [PMID: 31470680 PMCID: PMC6770952 DOI: 10.3390/genes10090662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/21/2019] [Accepted: 08/27/2019] [Indexed: 02/02/2023] Open
Abstract
Plants grown under highly variable natural light regimes differ strongly from plants grown under constant light (CL) regimes. Plant phenotype and adaptation responses are important for plant biomass and fitness. However, the underlying regulatory mechanisms are still poorly understood, particularly from a transcriptional perspective. To investigate the influence of different light regimes on tomato plants, three dynamic light (DL) regimes were designed, using a CL regime as control. Morphological, photosynthetic, and transcriptional differences after five weeks of treatment were compared. Leaf area, plant height, shoot /root weight, total chlorophyll content, photosynthetic rate, and stomatal conductance all significantly decreased in response to DL regimes. The biggest expression difference was found between the treatment with the highest light intensity at the middle of the day with a total of 1080 significantly up-/down-regulated genes. A total of 177 common differentially expressed genes were identified between DL and CL conditions. Finally, significant differences were observed in the levels of gene expression between DL and CL treatments in multiple pathways, predominantly of plant–pathogen interactions, plant hormone signal transductions, metabolites, and photosynthesis. These results expand the understanding of plant development and photosynthetic regulations under DL conditions by multiple pathways.
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Affiliation(s)
- Juanjuan Ding
- College of Horticulture, Northwest A&F University, Yangling 712100, China
| | - Jiantao Zhao
- INRA, UR1052, Génétique et Amélioration des Fruits et Légumes, Domaine Saint Maurice, 67 Allée des Chênes CS 60094, 84143 Montfavet, France
| | - Tonghua Pan
- College of Horticulture, Northwest A&F University, Yangling 712100, China
| | - Linjie Xi
- College of Horticulture, Northwest A&F University, Yangling 712100, China
| | - Jing Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, China
| | - Zhirong Zou
- College of Horticulture, Northwest A&F University, Yangling 712100, China.
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30
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Armarego-Marriott T, Kowalewska Ł, Burgos A, Fischer A, Thiele W, Erban A, Strand D, Kahlau S, Hertle A, Kopka J, Walther D, Reich Z, Schöttler MA, Bock R. Highly Resolved Systems Biology to Dissect the Etioplast-to-Chloroplast Transition in Tobacco Leaves. PLANT PHYSIOLOGY 2019; 180:654-681. [PMID: 30862726 PMCID: PMC6501100 DOI: 10.1104/pp.18.01432] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/19/2019] [Indexed: 05/17/2023]
Abstract
Upon exposure to light, plant cells quickly acquire photosynthetic competence by converting pale etioplasts into green chloroplasts. This developmental transition involves the de novo biogenesis of the thylakoid system and requires reprogramming of metabolism and gene expression. Etioplast-to-chloroplast differentiation involves massive changes in plastid ultrastructure, but how these changes are connected to specific changes in physiology, metabolism, and expression of the plastid and nuclear genomes is poorly understood. Here, we describe a new experimental system in the dicotyledonous model plant tobacco (Nicotiana tabacum) that allows us to study the leaf deetiolation process at the systems level. We have determined the accumulation kinetics of photosynthetic complexes, pigments, lipids, and soluble metabolites and recorded the dynamic changes in plastid ultrastructure and in the nuclear and plastid transcriptomes. Our data describe the greening process at high temporal resolution, resolve distinct genetic and metabolic phases during deetiolation, and reveal numerous candidate genes that may be involved in light-induced chloroplast development and thylakoid biogenesis.
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Affiliation(s)
| | - Łucja Kowalewska
- Faculty of Biology, Department of Plant Anatomy and Cytology, University of Warsaw, 02-096 Warszawa, Poland
| | - Asdrubal Burgos
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Laboratorio de Biotecnología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, CP 45200 Zapopan, Jalisco, Mexico
| | - Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Wolfram Thiele
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Alexander Erban
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Deserah Strand
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Sabine Kahlau
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- targenomix GmbH, 14476 Potsdam, Germany
| | - Alexander Hertle
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Joachim Kopka
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ziv Reich
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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31
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Vedalankar P, Tripathy BC. Evolution of light-independent protochlorophyllide oxidoreductase. PROTOPLASMA 2019; 256:293-312. [PMID: 30291443 DOI: 10.1007/s00709-018-1317-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/27/2018] [Indexed: 06/08/2023]
Abstract
The nonhomologous enzymes, the light-independent protochlorophyllide reductase (DPOR) and the light-dependent protochlorophyllide oxidoreductase (LPOR), catalyze the reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide) in the penultimate step of biosynthesis of chlorophyll (Chl) required for photosynthetic light absorption and energy conversion. The two enzymes differ with respect to the requirement of light for catalysis and oxygen sensitivity. DPOR and LPOR initially evolved in the ancestral prokaryotic genome perhaps at different times. DPOR originated in the anoxygenic environment of the Earth from nitrogenase-like enzyme of methanogenic archaea. Due to the transition from anoxygenic to oxygenic photosynthesis in the prokaryote, the DPOR was mostly inactivated in the daytime by photosynthetic O2 leading to the evolution of oxygen-insensitive LPOR that could function in the light. The primary endosymbiotic event transferred the DPOR and LPOR genes to the eukaryotic phototroph; the DPOR remained in the genome of the ancestor that turned into the plastid, whereas LPOR was transferred to the host nuclear genome. From an evolutionary point of view, several compelling theories that explain the disappearance of DPOR from several species cutting across different phyla are as follows: (i) pressure of the oxygenic environment; (ii) change in the light conditions and temperature; and (iii) lineage-specific gene losses, RNA editing, and nonsynonymous substitution. Certain primary amino acid sequence and the physiochemical properties of the ChlL subunit of DPOR have similarity with that of LPOR suggesting a convergence of these two enzymes in certain evolutionary event. The newly obtained sequence data from different phototrophs will further enhance the width of the phylogenetic information on DPOR.
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Affiliation(s)
| | - Baishnab C Tripathy
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Is the protection of photosynthesis related to the mechanism of quinclorac resistance in Echinochloa crus-galli var. zelayensis? Gene 2019; 683:133-148. [DOI: 10.1016/j.gene.2018.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/12/2018] [Accepted: 10/09/2018] [Indexed: 01/16/2023]
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Reinbothe S, Bartsch S, Rossig C, Davis MY, Yuan S, Reinbothe C, Gray J. A Protochlorophyllide (Pchlide) a Oxygenase for Plant Viability. FRONTIERS IN PLANT SCIENCE 2019; 10:593. [PMID: 31156665 PMCID: PMC6530659 DOI: 10.3389/fpls.2019.00593] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 04/24/2019] [Indexed: 05/19/2023]
Abstract
Higher plants contain a small, 5-member family of Rieske non-heme oxygenases that comprise the inner plastid envelope protein TIC55, phaeophorbide a oxygenasee (PAO), chlorophyllide a oxygenase (CAO), choline monooxygenase, and a 52 kDa protein (PTC52) associated with the precursor NADPH:protochlorophyllide (Pchlide) oxidoreductase A (pPORA) A translocon (PTC). Some of these chloroplast proteins have documented roles in chlorophyll biosynthesis (CAO) and degradation (PAO and TIC55), whereas the function of PTC52 remains unresolved. Biochemical evidence provided here identifies PTC52 as Pchlide a oxygenase of the inner plastid envelope linking Pchlide b synthesis to pPORA import. Protochlorophyllide b is the preferred substrate of PORA and its lack no longer allows pPORA import. The Pchlide b-dependent import pathway of pPORA thus operates in etiolated seedlings and is switched off during greening. Using dexamethasone-induced RNA interference (RNAi) we tested if PTC52 is involved in controlling both, pPORA import and Pchlide homeostasis in planta. As shown here, RNAi plants deprived of PTC52 transcript and PTC52 protein were unable to import pPORA and died as a result of excess Pchlide a accumulation causing singlet oxygen formation during greening. In genetic studies, no homozygous ptc52 knock-out mutants could be obtained presumably as a result of embryo lethality, suggesting a role for PTC52 in the initial greening of plant embryos. Phylogenetic studies identified PTC52-like genes amongst unicellular photosynthetic bacteria and higher plants, suggesting that the biochemical function associated with PTC52 may have an ancient evolutionary origin. PTC52 also harbors conserved motifs with bacterial oxygenases such as the terminal oxygenase component of 3-ketosteroid 9-alpha-hydroxylase (KshA) from Rhodococcus rhodochrous. 3D-modeling of PTC52 structure permitted the prediction of amino acid residues that contribute to the substrate specificity of this enzyme. In vitro-mutagenesis was used to test the predicted PTC52 model and provide insights into the reaction mechanism of this Rieske non-heme oxygenase.
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Affiliation(s)
- Steffen Reinbothe
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
- *Correspondence: Steffen Reinbothe, John Gray,
| | - Sandra Bartsch
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
| | - Claudia Rossig
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
| | | | - Shu Yuan
- College of Resources, Sichuan Agricultural University, Chengdu, China
| | - Christiane Reinbothe
- Laboratoire de Génétique Moléculaire des Plantes and Biologie Environnementale et Systémique (BEeSy), Université Grenoble Alpes, Grenoble, France
| | - John Gray
- Department of Biological Sciences, The University of Toledo, Toledo, OH, United States
- *Correspondence: Steffen Reinbothe, John Gray,
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Dogra V, Rochaix JD, Kim C. Singlet oxygen-triggered chloroplast-to-nucleus retrograde signalling pathways: An emerging perspective. PLANT, CELL & ENVIRONMENT 2018; 41:1727-1738. [PMID: 29749057 DOI: 10.1111/pce.13332] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 05/19/2023]
Abstract
Singlet oxygen (1 O2 ) is a prime cause of photo-damage of the photosynthetic apparatus. The chlorophyll molecules in the photosystem II reaction center and in the light-harvesting antenna complex are major sources of 1 O2 generation. It has been thought that the generation of 1 O2 mainly takes place in the appressed regions of the thylakoid membranes, namely, the grana core, where most of the active photosystem II complexes are localized. Apart from being a toxic molecule, new evidence suggests that 1 O2 significantly contributes to chloroplast-to-nucleus retrograde signalling that primes acclimation and cell death responses. Interestingly, recent studies reveal that chloroplasts operate two distinct 1 O2 -triggered retrograde signalling pathways in which β-carotene and a nuclear-encoded chloroplast protein EXECUTER1 play essential roles as signalling mediators. The coexistence of these mediators raises several questions: their crosstalk, source(s) of 1 O2 , downstream signalling components, and the perception and reaction mechanism of these mediators towards 1 O2 . In this review, we mainly discuss the molecular genetic basis of the mode of action of these two putative 1 O2 sensors and their corresponding retrograde signalling pathways. In addition, we also propose the possible existence of an alternative source of 1 O2 , which is spatially and functionally separated from the grana core.
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Affiliation(s)
- Vivek Dogra
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jean-David Rochaix
- Department of Molecular Biology and Plant Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology and Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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35
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Killiny N, Hijaz F, Nehela Y, Hajeri S, Gowda S. Effects of δ-aminolevulinic acid dehydratase silencing on the primary and secondary metabolisms of citrus. PLANT DIRECT 2018; 2:e00072. [PMID: 31245736 PMCID: PMC6508816 DOI: 10.1002/pld3.72] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/18/2018] [Accepted: 06/26/2018] [Indexed: 05/07/2023]
Abstract
δ-aminolevulinic acid dehydratase (ALAD) is an important enzyme in tetrapyrrole synthesis. ALAD combines two δ-aminolevulinic acid (δ-ALA) molecules to form the pyrrole molecule, porphobilinogen, an important precursor for plant pigments involved in photosynthesis, respiration, and nutrient uptake. In this study, we investigated the effects of silencing of ALAD gene on citrus leaf pigments and metabolites. The ALAD enzyme was inhibited using virus-induced gene silencing (VIGS) technology using citrus tristeza virus (CTV). δ-ALA accumulated in citrus plants inoculated with the recombinant virus (CTV-tALAD) to silence ALAD and resulted in discrete yellow spots (yellow islands) and necrosis in leaves and stems. The levels of chlorophylls, starch, sucrose, trans- and cis-violaxanthin, and α- and β-cryptoxanthin were reduced in CTV-tALAD plants, whereas zeaxanthin was increased. The increase in zeaxanthin and the decrease in its precursors indicated that the reduction in chlorophylls resulted in light damage. Salicylic acid and jasmonic acid levels, as well as emission of (E)-α-bergamotene and (E)-β-farnesene, increased in CTV-tALAD plants indicating these plants were under stress. Our results showed that silencing of ALAD induces stress in plants and that VIGS using mild CTV strains is a promising technique to study biological function of citrus genes.
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Affiliation(s)
- Nabil Killiny
- Department of Plant PathologyCitrus Research and Education CenterIFASUniversity of FloridaLake AlfredFlorida
| | - Faraj Hijaz
- Department of Plant PathologyCitrus Research and Education CenterIFASUniversity of FloridaLake AlfredFlorida
| | - Yasser Nehela
- Department of Plant PathologyCitrus Research and Education CenterIFASUniversity of FloridaLake AlfredFlorida
| | - Subhas Hajeri
- Department of Plant PathologyCitrus Research and Education CenterIFASUniversity of FloridaLake AlfredFlorida
- Present address:
Citrus Pest Detection ProgramCentral California Tristeza Eradication AgencyTulareCalifornia
| | - Siddarame Gowda
- Department of Plant PathologyCitrus Research and Education CenterIFASUniversity of FloridaLake AlfredFlorida
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Przybyla-Toscano J, Roland M, Gaymard F, Couturier J, Rouhier N. Roles and maturation of iron-sulfur proteins in plastids. J Biol Inorg Chem 2018; 23:545-566. [PMID: 29349662 PMCID: PMC6006212 DOI: 10.1007/s00775-018-1532-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/14/2017] [Indexed: 12/28/2022]
Abstract
One reason why iron is an essential element for most organisms is its presence in prosthetic groups such as hemes or iron–sulfur (Fe–S) clusters, which are notably required for electron transfer reactions. As an organelle with an intense metabolism in plants, chloroplast relies on many Fe–S proteins. This includes those present in the electron transfer chain which will be, in fact, essential for most other metabolic processes occurring in chloroplasts, e.g., carbon fixation, nitrogen and sulfur assimilation, pigment, amino acid, and vitamin biosynthetic pathways to cite only a few examples. The maturation of these Fe–S proteins requires a complex and specific machinery named SUF (sulfur mobilisation). The assembly process can be split in two major steps, (1) the de novo assembly on scaffold proteins which requires ATP, iron and sulfur atoms, electrons, and thus the concerted action of several proteins forming early acting assembly complexes, and (2) the transfer of the preformed Fe–S cluster to client proteins using a set of late-acting maturation factors. Similar machineries, having in common these basic principles, are present in the cytosol and in mitochondria. This review focuses on the currently known molecular details concerning the assembly and roles of Fe–S proteins in plastids.
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Affiliation(s)
- Jonathan Przybyla-Toscano
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Mélanie Roland
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Frédéric Gaymard
- Biochimie et Physiologie Moléculaire des Plantes, CNRS/INRA/Université Montpellier 2, SupAgro Campus, 34060, Montpellier, France
| | - Jérémy Couturier
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France
| | - Nicolas Rouhier
- Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, 54500, Vandoeuvre-lès-Nancy, France.
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Synthesis of 7-substituted chlorophyll- a derivatives as chlorophyll- b analogs with specific visible absorption bands. Tetrahedron 2018. [DOI: 10.1016/j.tet.2017.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Malnoë A, Schultink A, Shahrasbi S, Rumeau D, Havaux M, Niyogi KK. The Plastid Lipocalin LCNP Is Required for Sustained Photoprotective Energy Dissipation in Arabidopsis. THE PLANT CELL 2018; 30:196-208. [PMID: 29233855 PMCID: PMC5810567 DOI: 10.1105/tpc.17.00536] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 11/01/2017] [Accepted: 12/08/2017] [Indexed: 05/18/2023]
Abstract
Light utilization is finely tuned in photosynthetic organisms to prevent cellular damage. The dissipation of excess absorbed light energy, a process termed nonphotochemical quenching (NPQ), plays an important role in photoprotection. Little is known about the sustained or slowly reversible form(s) of NPQ and whether they are photoprotective, in part due to the lack of mutants. The Arabidopsis thaliana suppressor of quenching1 (soq1) mutant exhibits enhanced sustained NPQ, which we term qH. To identify molecular players involved in qH, we screened for suppressors of soq1 and isolated mutants affecting either chlorophyllide a oxygenase or the chloroplastic lipocalin, now renamed plastid lipocalin (LCNP). Analysis of the mutants confirmed that qH is localized to the peripheral antenna (LHCII) of photosystem II and demonstrated that LCNP is required for qH, either directly (by forming NPQ sites) or indirectly (by modifying the LHCII membrane environment). qH operates under stress conditions such as cold and high light and is photoprotective, as it reduces lipid peroxidation levels. We propose that, under stress conditions, LCNP protects the thylakoid membrane by enabling sustained NPQ in LHCII, thereby preventing singlet oxygen stress.
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Affiliation(s)
- Alizée Malnoë
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Alex Schultink
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Sanya Shahrasbi
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
| | - Dominique Rumeau
- CEA, CNRS UMR 7265, Biologie Végétale et Microbiologie Environnementales, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance 13108, France
| | - Michel Havaux
- CEA, CNRS UMR 7265, Biologie Végétale et Microbiologie Environnementales, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance 13108, France
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720
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Tyutereva EV, Evkaikina AI, Ivanova AN, Voitsekhovskaja OV. The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants. PHOTOSYNTHESIS RESEARCH 2017; 133:357-370. [PMID: 28382592 DOI: 10.1007/s11120-017-0376-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/24/2017] [Indexed: 06/07/2023]
Abstract
The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.
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Affiliation(s)
- Elena V Tyutereva
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376, Saint-Petersburg, Russia
| | - Anastasiia I Evkaikina
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376, Saint-Petersburg, Russia
| | - Alexandra N Ivanova
- Laboratory of Plant Anatomy and Morphology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376, Saint-Petersburg, Russia
| | - Olga V Voitsekhovskaja
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, ul. Professora Popova 2, 197376, Saint-Petersburg, Russia.
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Sheng Z, Lv Y, Li W, Luo R, Wei X, Xie L, Jiao G, Shao G, Wang J, Tang S, Hu P. Yellow-Leaf 1 encodes a magnesium-protoporphyrin IX monomethyl ester cyclase, involved in chlorophyll biosynthesis in rice (Oryza sativa L.). PLoS One 2017; 12:e0177989. [PMID: 28558018 PMCID: PMC5448749 DOI: 10.1371/journal.pone.0177989] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/06/2017] [Indexed: 01/09/2023] Open
Abstract
Magnesium-protoporphyrin IX monomethyl ester cyclase (MPEC) catalyzes the conversion of MPME to divinyl protochlorophyllide (DVpchlide). This is an essential enzyme during chlorophyll (Chl) biosynthesis but details of its function in rice are still lacking. Here, we identified a novel rice mutant yellow-leaf 1 (yl-1), which showed decreased Chl accumulation, abnormal chloroplast ultrastructure and attenuated photosynthetic activity. Map-based cloning and over-expression analysis suggested that YL-1 encodes a subunit of MPEC. The YL-1 protein localizes in chloroplasts, and it is mainly expressed in green tissues, with greatest abundance in leaves and young panicles. Results of qRT-PCR showed that Chl biosynthesis upstream genes were highly expressed in the yl-1 mutant, while downstream genes were compromised, indicating that YL-1 plays a pivotal role in the Chl biosynthesis. Furthermore, the expression levels of photosynthesis and chloroplast development genes were also affected. RNA-seq results futher proved that numerous membrane-associated genes, including many plastid membrane-associated genes, have altered expression pattern in the yl-1 mutant, implying that YL-1 is required for plastid membrane stability. Thus, our study confirms a putative MPME cyclase as a novel key enzyme essential for Chl biosynthesis and chloroplast membrane stability in rice.
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Affiliation(s)
- Zhonghua Sheng
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Yusong Lv
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Wei Li
- Agricultural College of Hunan Agricultural University, Changsha, China
| | - Rongjian Luo
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Xiangjin Wei
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Lihong Xie
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Guiai Jiao
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Gaoneng Shao
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
| | - Jianlong Wang
- Agricultural College of Hunan Agricultural University, Changsha, China
| | - Shaoqing Tang
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
- * E-mail: (PH); (ST)
| | - Peisong Hu
- State Key Laboratory of Rice Biology, Key Laboratory of Rice Biology and Breeding of Ministry of Agriculture, China National Rice Research Institute, Hangzhou, China
- * E-mail: (PH); (ST)
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Dmitrieva VA, Ivanova AN, Tyutereva EV, Evkaikina AI, Klimova EA, Voitsekhovskaja OV. Chlorophyllide-a-Oxygenase (CAO) deficiency affects the levels of singlet oxygen and formation of plasmodesmata in leaves and shoot apical meristems of barley. PLANT SIGNALING & BEHAVIOR 2017; 12:e1300732. [PMID: 28272988 PMCID: PMC5437820 DOI: 10.1080/15592324.2017.1300732] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 05/19/2023]
Abstract
In plants, organogenesis and specification of cell layers and tissues rely on precise symplastic delivery of regulatory molecules via plasmodesmata. Accordingly, abundance and aperture of plasmodesmata at individual cell boundaries should be controlled by the plant. Recently, studies in Arabidopsis established reactive oxygen species as major regulators of plasmodesmata formation and gating. We show that in a barley mutant deficient in the synthesis of chlorophyll b, the numbers of plasmodesmata in leaves and in the shoot apical meristem are significantly higher than in the corresponding wild type, probably due to redox imbalance in the mutant. The resulting disturbance of symplasmic transport is likely to be the reason for the observed delayed floral transition in these mutants.
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Affiliation(s)
- Valeria A. Dmitrieva
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
| | - Alexandra N. Ivanova
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
- Laboratory of Plant Anatomy and Morphology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
| | - Elena V. Tyutereva
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
| | - Anastasiia I. Evkaikina
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
| | - Ekaterina A. Klimova
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
| | - Olga V. Voitsekhovskaja
- Laboratory of Plant Ecological Physiology, Komarov Botanical Institute, Russian Academy of Sciences, St.-Petersburg, Russia
- CONTACT Olga V. Voitsekhovskaja Plant Ecological Physiology, Komarov Botanical Institute RAS, ul. Professora Popova, 2, Saint Petersburg, 197376, Russia
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Hu X, Page MT, Sumida A, Tanaka A, Terry MJ, Tanaka R. The iron-sulfur cluster biosynthesis protein SUFB is required for chlorophyll synthesis, but not phytochrome signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:1184-1194. [PMID: 28004871 PMCID: PMC5347852 DOI: 10.1111/tpj.13455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/07/2016] [Accepted: 12/09/2016] [Indexed: 05/08/2023]
Abstract
Proteins that contain iron-sulfur (Fe-S) clusters play pivotal roles in various metabolic processes such as photosynthesis and redox metabolism. Among the proteins involved in the biosynthesis of Fe-S clusters in plants, the SUFB subunit of the SUFBCD complex appears to be unique because SUFB has been reported to be involved in chlorophyll metabolism and phytochrome-mediated signaling. To gain insights into the function of the SUFB protein, we analyzed the phenotypes of two SUFB mutants, laf6 and hmc1, and RNA interference (RNAi) lines with reduced SUFB expression. When grown in the light, the laf6 and hmc1 mutants and the SUFB RNAi lines accumulated higher levels of the chlorophyll biosynthesis intermediate Mg-protoporphyrin IX monomethylester (Mg-proto MME), consistent with the impairment of Mg-proto MME cyclase activity. Both SUFC- and SUFD-deficient RNAi lines accumulated the same intermediate, suggesting that inhibition of Fe-S cluster synthesis is the primary cause of this impairment. Dark-grown laf6 seedlings also showed an increase in protoporphyrin IX (Proto IX), Mg-proto, Mg-proto MME and 3,8-divinyl protochlorophyllide a (DV-Pchlide) levels, but this was not observed in hmc1 or the SUFB RNAi lines, nor was it complemented by SUFB overexpression. In addition, the long hypocotyl in far-red light phenotype of the laf6 mutant could not be rescued by SUFB overexpression and segregated from the pale-green SUFB-deficient phenotype, indicating it is not caused by mutation at the SUFB locus. These results demonstrate that biosynthesis of Fe-S clusters is important for chlorophyll biosynthesis, but that the laf6 phenotype is not due to a SUFB mutation.
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Affiliation(s)
- Xueyun Hu
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
- School of Life Science and EngineeringSouthwest University of Science and TechnologyMianyang621010China
| | - Mike T. Page
- Biological SciencesUniversity of SouthamptonSouthamptonUK
| | - Akihiro Sumida
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
| | - Ayumi Tanaka
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
| | - Matthew J. Terry
- Biological SciencesUniversity of SouthamptonSouthamptonUK
- Institute for Life SciencesUniversity of SouthamptonSouthamptonUK
| | - Ryouichi Tanaka
- Institute of Low Temperature ScienceHokkaido UniversitySapporo060‐0819Japan
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Shumbe L, D'Alessandro S, Shao N, Chevalier A, Ksas B, Bock R, Havaux M. METHYLENE BLUE SENSITIVITY 1 (MBS1) is required for acclimation of Arabidopsis to singlet oxygen and acts downstream of β-cyclocitral. PLANT, CELL & ENVIRONMENT 2017; 40:216-226. [PMID: 27813110 DOI: 10.1111/pce.12856] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 05/19/2023]
Abstract
Singlet oxygen (1 O2 ) signalling in plants is essential to trigger both acclimatory mechanisms and programmed cell death under high light stress. However, because of its chemical features, 1 O2 requires mediators, and the players involved in this pathway are largely unknown. The β-carotene oxidation product, β-cyclocitral, is one such mediator. Produced in the chloroplast, β-cyclocitral induces changes in nuclear gene expression leading to photoacclimation. Recently, the METHYLENE BLUE SENSITIVITY protein MBS has been identified as a key player in 1 O2 signalling leading to tolerance to high light. Here, we provide evidence that MBS1 is essential for acclimation to 1 O2 and cross-talks with β-cyclocitral to mediate transfer of the 1 O2 signal to the nucleus, leading to photoacclimation. The presented results position MBS1 downstream of β-cyclocitral in 1 O2 signalling and suggest an additional role for MBS1 in the regulation of plant growth and development under chronic 1 O2 production.
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Affiliation(s)
- Leonard Shumbe
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108, Saint-Paul-lez-Durance, France
| | - Stefano D'Alessandro
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108, Saint-Paul-lez-Durance, France
| | - Ning Shao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101, Beijing, China
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476, Potsdam-Golm, Germany
| | - Anne Chevalier
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108, Saint-Paul-lez-Durance, France
| | - Brigitte Ksas
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108, Saint-Paul-lez-Durance, France
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476, Potsdam-Golm, Germany
| | - Michel Havaux
- CEA Cadarache, CNRS UMR 7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108, Saint-Paul-lez-Durance, France
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Buendía-Monreal M, Gillmor CS. Convergent repression of miR156 by sugar and the CDK8 module of Arabidopsis Mediator. Dev Biol 2017; 423:19-23. [PMID: 28108181 DOI: 10.1016/j.ydbio.2017.01.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 01/05/2017] [Accepted: 01/10/2017] [Indexed: 01/19/2023]
Abstract
In Arabidopsis, leaves produced during the juvenile vegetative phase are simple, while adult leaves are morphologically complex. The juvenile to adult transition is regulated by miR156, a microRNA that promotes juvenility by impeding the function of SPL transcription factors, which specify adult leaf traits. Both leaf derived sugars, as well as the Mediator Cyclin Dependent Kinase 8 (CDK8) module genes CENTER CITY (CCT)/MED12 and GRAND CENTRAL (GCT)/MED13, act upstream of miR156 to promote the juvenile to adult transition. However, it is not known whether sugar, CCT and GCT repress miR156 independently, as part of the same pathway, or in a cooperative manner. Here we show that sugar treatment can repress MIR156 expression in the absence of CCT or GCT. Both cct and the photosynthetic mutant chlorina1 (ch1) (which decreases sugar synthesis) exhibit extended juvenile development and increased MIR156A and MIR156C expression. Compared to ch1 and cct single mutants, the ch1 cct double mutant has a stronger effect on juvenile leaf traits, higher MIR156C levels, and a dramatic increase in MIR156A. Our results show that sugar and the CDK8 module are capable of regulating MIR156 independently, but suggest they normally act together in a synergistic manner.
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Affiliation(s)
- Manuel Buendía-Monreal
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Irapuato, Guanajuato, Mexico
| | - C Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Irapuato, Guanajuato, Mexico.
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Bujaldon S, Kodama N, Rappaport F, Subramanyam R, de Vitry C, Takahashi Y, Wollman FA. Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii. MOLECULAR PLANT 2017; 10:115-130. [PMID: 27742488 DOI: 10.1016/j.molp.2016.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 09/01/2016] [Accepted: 10/04/2016] [Indexed: 05/29/2023]
Abstract
The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes (LHC): four major LHCIIs, two minor LHCIIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHCIIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCI accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background (yid-BF3), in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHCIIs and of most LHCIs was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna proteins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid-BF3-ftsh1 restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease.
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Affiliation(s)
- Sandrine Bujaldon
- Institut de Biologie Physico-Chimique, UMR7141 CNRS-UPMC, Paris 75005, France
| | - Natsumi Kodama
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan; JST-CREST, Okayama University, Okayama 700-8530, Japan
| | - Fabrice Rappaport
- Institut de Biologie Physico-Chimique, UMR7141 CNRS-UPMC, Paris 75005, France
| | - Rajagopal Subramanyam
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Catherine de Vitry
- Institut de Biologie Physico-Chimique, UMR7141 CNRS-UPMC, Paris 75005, France
| | - Yuichiro Takahashi
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan; JST-CREST, Okayama University, Okayama 700-8530, Japan.
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Wang P, Grimm B. Comparative Analysis of Light-Harvesting Antennae and State Transition in chlorina and cpSRP Mutants. PLANT PHYSIOLOGY 2016; 172:1519-1531. [PMID: 27663408 PMCID: PMC5100790 DOI: 10.1104/pp.16.01009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/21/2016] [Indexed: 05/23/2023]
Abstract
State transitions in photosynthesis provide for the dynamic allocation of a mobile fraction of light-harvesting complex II (LHCII) to photosystem II (PSII) in state I and to photosystem I (PSI) in state II. In the state I-to-state II transition, LHCII is phosphorylated by STN7 and associates with PSI to favor absorption cross-section of PSI. Here, we used Arabidopsis (Arabidopsis thaliana) mutants with defects in chlorophyll (Chl) b biosynthesis or in the chloroplast signal recognition particle (cpSRP) machinery to study the flexible formation of PS-LHC supercomplexes. Intriguingly, we found that impaired Chl b biosynthesis in chlorina1-2 (ch1-2) led to preferentially stabilized LHCI rather than LHCII, while the contents of both LHCI and LHCII were equally depressed in the cpSRP43-deficient mutant (chaos). In view of recent findings on the modified state transitions in LHCI-deficient mutants (Benson et al., 2015), the ch1-2 and chaos mutants were used to assess the influence of varying LHCI/LHCII antenna size on state transitions. Under state II conditions, LHCII-PSI supercomplexes were not formed in both ch1-2 and chaos plants. LHCII phosphorylation was drastically reduced in ch1-2, and the inactivation of STN7 correlates with the lack of state transitions. In contrast, phosphorylated LHCII in chaos was observed to be exclusively associated with PSII complexes, indicating a lack of mobile LHCII in chaos Thus, the comparative analysis of ch1-2 and chaos mutants provides new evidence for the flexible organization of LHCs and enhances our understanding of the reversible allocation of LHCII to the two photosystems.
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Affiliation(s)
- Peng Wang
- Department of Plant Physiology, Humboldt University Berlin, 10115 Berlin, Germany
| | - Bernhard Grimm
- Department of Plant Physiology, Humboldt University Berlin, 10115 Berlin, Germany
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Jia T, Ito H, Tanaka A. Simultaneous regulation of antenna size and photosystem I/II stoichiometry in Arabidopsis thaliana. PLANTA 2016; 244:1041-1053. [PMID: 27394155 DOI: 10.1007/s00425-016-2568-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/06/2016] [Indexed: 05/10/2023]
Abstract
The photosystem I/II ratio increased when antenna size was enlarged by transient induction of CAO in chlorophyll b -less mutants, thus indicating simultaneous regulation of antenna size and photosystem I/II stoichiometry. Regulation of antenna size and photosystem I/II stoichiometry is an indispensable strategy for plants to acclimate to changes to light environments. When plants grown in high-light conditions are transferred to low-light conditions, the peripheral antennae of photosystems are enlarged. A change in the photosystem I/II ratio is also observed under the same light conditions. However, our knowledge of the correlation between antenna size modulation and variation in photosystem I/II stoichiometry remains limited. In this study, chlorophyll a oxygenase was transiently induced in Arabidopsis thaliana chlorophyll b-less mutants, ch1-1, to alter the antenna size without changing environmental conditions. In addition to the accumulation of chlorophyll b, the levels of the peripheral antenna complexes of both photosystems gradually increased, and these were assembled to the core antenna of both photosystems. However, the antenna size of photosystem II was greater than that of photosystem I. Immunoblot analysis of core antenna proteins showed that the number of photosystem I increased, but not that of photosystem II, resulting in an increase in the photosystem I/II ratio. These results clearly indicate that antenna size adjustment was coupled with changes in photosystem I/II stoichiometry. Based on these results, the physiological importance of simultaneous regulation of antenna size and photosystem I/II stoichiometry is discussed in relation to acclimation to light conditions.
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Affiliation(s)
- Ting Jia
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan
| | - Hisashi Ito
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan.
- CREST, Japan Science and Technology Agency, N19 W8, Kita-ku, Sapporo, 060-0819, Japan.
| | - Ayumi Tanaka
- Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo, 060-0819, Japan
- CREST, Japan Science and Technology Agency, N19 W8, Kita-ku, Sapporo, 060-0819, Japan
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Li CF, Xu YX, Ma JQ, Jin JQ, Huang DJ, Yao MZ, Ma CL, Chen L. Biochemical and transcriptomic analyses reveal different metabolite biosynthesis profiles among three color and developmental stages in 'Anji Baicha' (Camellia sinensis). BMC PLANT BIOLOGY 2016; 16:195. [PMID: 27609021 PMCID: PMC5015330 DOI: 10.1186/s12870-016-0885-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/31/2016] [Indexed: 05/02/2023]
Abstract
BACKGROUND The new shoots of the albino tea cultivar 'Anji Baicha' are yellow or white at low temperatures and turn green as the environmental temperatures increase during the early spring. 'Anji Baicha' metabolite profiles exhibit considerable variability over three color and developmental stages, especially regarding the carotenoid, chlorophyll, and theanine concentrations. Previous studies focused on physiological characteristics, gene expression differences, and variations in metabolite abundances in albino tea plant leaves at specific growth stages. However, the molecular mechanisms regulating metabolite biosynthesis in various color and developmental stages in albino tea leaves have not been fully characterized. RESULTS We used RNA-sequencing to analyze 'Anji Baicha' leaves at the yellow-green, albescent, and re-greening stages. The leaf transcriptomes differed considerably among the three stages. Functional classifications based on Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that differentially expressed unigenes were mainly related to metabolic pathways, biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, and carbon fixation in photosynthetic organisms. Chemical analyses revealed higher β-carotene and theanine levels, but lower chlorophyll a levels, in the albescent stage than in the green stage. Furthermore, unigenes involved in carotenoid, chlorophyll, and theanine biosyntheses were identified, and the expression patterns of the differentially expressed unigenes in these biosynthesis pathways were characterized. Through co-expression analyses, we identified the key genes in these pathways. These genes may be responsible for the metabolite biosynthesis differences among the different leaf color and developmental stages of 'Anji Baicha' tea plants. CONCLUSIONS Our study presents the results of transcriptomic and biochemical analyses of 'Anji Baicha' tea plants at various stages. The distinct transcriptome profiles for each color and developmental stage enabled us to identify changes to biosynthesis pathways and revealed the contributions of such variations to the albino phenotype of tea plants. Furthermore, comparisons of the transcriptomes and related metabolites helped clarify the molecular regulatory mechanisms underlying the secondary metabolic pathways in different stages.
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Affiliation(s)
- Chun-Fang Li
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
- School of Agriculture and Food Science, Zhejiang Agriculture and Forestry University, Lin’an, Hangzhou China
| | - Yan-Xia Xu
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Jian-Qiang Ma
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Ji-Qiang Jin
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Dan-Juan Huang
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Ming-Zhe Yao
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Chun-Lei Ma
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Liang Chen
- Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou, China
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Yokoyama R, Yamamoto H, Kondo M, Takeda S, Ifuku K, Fukao Y, Kamei Y, Nishimura M, Shikanai T. Grana-Localized Proteins, RIQ1 and RIQ2, Affect the Organization of Light-Harvesting Complex II and Grana Stacking in Arabidopsis. THE PLANT CELL 2016; 28:2261-2275. [PMID: 27600538 PMCID: PMC5059800 DOI: 10.1105/tpc.16.00296] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 08/01/2016] [Accepted: 09/03/2016] [Indexed: 05/18/2023]
Abstract
Grana are stacked thylakoid membrane structures in land plants that contain PSII and light-harvesting complex II proteins (LHCIIs). We isolated two Arabidopsis thaliana mutants, reduced induction of non-photochemical quenching1 (riq1) and riq2, in which stacking of grana was enhanced. The curvature thylakoid 1a (curt1a) mutant was previously shown to lack grana structure. In riq1 curt1a, the grana were enlarged with more stacking, and in riq2 curt1a, the thylakoids were abnormally stacked and aggregated. Despite having different phenotypes in thylakoid structure, riq1, riq2, and curt1a showed a similar defect in the level of nonphotochemical quenching of chlorophyll fluorescence (NPQ). In riq curt1a double mutants, NPQ induction was more severely affected than in either single mutant. In riq mutants, state transitions were inhibited and the PSII antennae were smaller than in wild-type plants. The riq defects did not affect NPQ induction in the chlorophyll b-less mutant. RIQ1 and RIQ2 are paralogous and encode uncharacterized grana thylakoid proteins, but despite the high level of identity of the sequence, the functions of RIQ1 and RIQ2 were not redundant. RIQ1 is required for RIQ2 accumulation, and the wild-type level of RIQ2 did not complement the NPQ and thylakoid phenotypes in riq1 We propose that RIQ proteins link the grana structure and organization of LHCIIs.
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Affiliation(s)
- Ryo Yokoyama
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hiroshi Yamamoto
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
| | - Maki Kondo
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
- Spectrography and Bioimaging Facility, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Satomi Takeda
- Department of Biological Science, Graduate School of Science, Osaka Prefecture University, Sakai 599-8531, Japan
| | - Kentaro Ifuku
- Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502 Japan
| | - Yoichiro Fukao
- Department of Bioinformatics, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Yasuhiro Kamei
- Spectrography and Bioimaging Facility, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Mikio Nishimura
- Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Toshiharu Shikanai
- Department of Botany, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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Rosianskey Y, Dahan Y, Yadav S, Freiman ZE, Milo-Cochavi S, Kerem Z, Eyal Y, Flaishman MA. Chlorophyll metabolism in pollinated vs. parthenocarpic fig fruits throughout development and ripening. PLANTA 2016; 244:491-504. [PMID: 27097639 DOI: 10.1007/s00425-016-2522-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/06/2016] [Indexed: 05/14/2023]
Abstract
Expression of 13 genes encoding chlorophyll biosynthesis and degradation was evaluated. Chlorophyll degradation was differentially regulated in pollinated and parthenocarpic fig fruits, leading to earlier chlorophyll degradation in parthenocarpic fruits. Varieties of the common fig typically yield a commercial summer crop that requires no pollination, although it can be pollinated. Fig fruit pollination results in larger fruit size, greener skin and darker interior inflorescence color, and slows the ripening process compared to non-pollinated fruits. We evaluated the effect of pollination on chlorophyll content and levels of transcripts encoding enzymes of the chlorophyll metabolism in fruits of the common fig 'Brown Turkey'. We cloned and evaluated the expression of 13 different genes. All 13 genes showed high expression in the fruit skin, inflorescences and leaves, but extremely low expression in roots. Pollination delayed chlorophyll breakdown in the ripening fruit skin and inflorescences. This was correlated with the expression of genes encoding enzymes in the chlorophyll biosynthesis and degradation pathways. Expression of pheophorbide a oxygenase (PAO) was strongly negatively correlated with chlorophyll levels during ripening in pollinated fruits; along with its high expression levels in yellow leaves, this supports a pivotal role for PAO in chlorophyll degradation in figs. Normalizing expression levels of all chlorophyll metabolism genes in the pollinated and parthenocarpic fruit skin and inflorescences showed three synthesis (FcGluTR1, FcGluTR2 and FcCLS1) and three degradation (FcCLH1, FcCLH2 and FcRCCR1) genes with different temporal expression in the pollinated vs. parthenocarpic fruit skin and inflorescences. FcCAO also showed different expressions in the parthenocarpic fruit skin. Thus, chlorophyll degradation is differentially regulated in the pollinated and parthenocarpic fruit skin and inflorescences, leading to earlier and more sustained chlorophyll degradation in the parthenocarpic fruit.
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Affiliation(s)
- Yogev Rosianskey
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, 76100, Rehovot, Israel
| | - Yardena Dahan
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
| | - Sharawan Yadav
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
| | - Zohar E Freiman
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
| | - Shira Milo-Cochavi
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
| | - Zohar Kerem
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, 76100, Rehovot, Israel
| | - Yoram Eyal
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel
| | - Moshe A Flaishman
- Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
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