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Guan Q, Kong W, Tan B, Zhu W, Akter T, Li J, Tian J, Chen S. Multiomics unravels potential molecular switches in the C 3 to CAM transition of Mesembryanthemum crystallinum. J Proteomics 2024; 299:105145. [PMID: 38431086 DOI: 10.1016/j.jprot.2024.105145] [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: 01/08/2024] [Revised: 02/21/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024]
Abstract
Mesembryanthemum crystallinum (common ice plant), a facultative CAM plant, shifts from C3 to CAM photosynthesis under salt stress, enhancing water use efficiency. Here we used transcriptomics, proteomics, and targeted metabolomics to profile molecular changes during the diel cycle of C3 to CAM transition. The results confirmed expected changes associated with CAM photosynthesis, starch biosynthesis and degradation, and glycolysis/gluconeogenesis. Importantly, they yielded new discoveries: 1) Transcripts displayed greater circadian regulation than proteins. 2) Oxidative phosphorylation and inositol methylation may play important roles in initiating the transition. 3) V-type H+-ATPases showed consistent transcriptional regulation, aiding in vacuolar malate uptake. 4) A protein phosphatase 2C, a major component in the ABA signaling pathway, may trigger the C3 to CAM transition. Our work highlights the potential molecular switches in the C3 to CAM transition, including the potential role of ABA signaling. SIGNIFICANCE: The common ice plant is a model facultative CAM plant, and under stress conditions it can shift from C3 to CAM photosynthesis within a three-day period. However, knowledge about the molecular changes during the transition and the molecular switches enabling the transition is lacking. Multi-omic analyses not only revealed the molecular changes during the transition, but also highlighted the importance of ABA signaling, inositol methylation, V-type H+-ATPase in initiating the shift. The findings may explain physiological changes and nocturnal stomatal opening, and inform future synthetic biology effort in improving crop water use efficiency and stress resilience.
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Affiliation(s)
- Qijie Guan
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA
| | - Wenwen Kong
- College of Life Sciences, Northeast Agricultural University, Harbin 150040, China
| | - Bowen Tan
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA
| | - Wei Zhu
- Institute of Basic Medicine and Cancer, Chinese Academy of Sciences, Hangzhou 310002, China
| | - Tahmina Akter
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA
| | - Jing Li
- College of Life Sciences, Northeast Agricultural University, Harbin 150040, China
| | - Jingkui Tian
- Institute of Basic Medicine and Cancer, Chinese Academy of Sciences, Hangzhou 310002, China
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA.
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Liu Z, Shen S, Wang Y, Sun S, Yu T, Fu Y, Zhou R, Li C, Cao R, Zhang Y, Li N, Sun L, Song X. The genome of Stephania japonica provides insights into the biosynthesis of cepharanthine. Cell Rep 2024; 43:113832. [PMID: 38381605 DOI: 10.1016/j.celrep.2024.113832] [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: 08/15/2023] [Revised: 12/28/2023] [Accepted: 02/02/2024] [Indexed: 02/23/2024] Open
Abstract
Stephania japonica is an early-diverging eudicotyledon plant with high levels of cepharanthine, proven to be effective in curing coronavirus infections. Here, we report a high-quality S. japonica genome. The genome size is 688.52 Mb, and 97.37% sequences anchor to 11 chromosomes. The genome comprises 67.46% repetitive sequences and 21,036 genes. It is closely related to two Ranunculaceae species, which diverged from their common ancestor 55.90-71.02 million years ago (Mya) with a whole-genome duplication 85.59-96.75 Mya. We further reconstruct ancestral karyotype of Ranunculales. Several cepharanthine biosynthesis genes are identified and verified by western blot. Two genes (Sja03G0243 and Sja03G0241) exhibit catalytic activity as shown by liquid chromatography-mass spectrometry. Then, cepharanthine biosynthesis genes, transcription factors, and CYP450 family genes are used to construct a comprehensive network. Finally, we construct an early-diverging eudicotyledonous genome resources (EEGR) database. As the first genome of the Menispermaceae family to be released, this study provides rich resources for genomic studies.
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Affiliation(s)
- Zhuo Liu
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Shaoqin Shen
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Yujie Wang
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Shuqi Sun
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Tong Yu
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Yanhong Fu
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Rong Zhou
- Department of Food Science, Aarhus University, 8200 Aarhus, Denmark
| | - Chunjin Li
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Rui Cao
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Yanshu Zhang
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Nan Li
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China.
| | - Liangdan Sun
- North China University of Science and Technology Affiliated Hospital, Tangshan 063000, China; Health Science Center, North China University of Science and Technology, Tangshan 063210, China; Inflammation and Immune Diseases Laboratory of North China University of Science and Technology, Tangshan 063210, China; School of Public Health, North China University of Science and Technology, Tangshan 063210, China.
| | - Xiaoming Song
- College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China.
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Perron N, Kirst M, Chen S. Bringing CAM photosynthesis to the table: Paving the way for resilient and productive agricultural systems in a changing climate. PLANT COMMUNICATIONS 2024; 5:100772. [PMID: 37990498 PMCID: PMC10943566 DOI: 10.1016/j.xplc.2023.100772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/27/2023] [Accepted: 11/20/2023] [Indexed: 11/23/2023]
Abstract
Modern agricultural systems are directly threatened by global climate change and the resulting freshwater crisis. A considerable challenge in the coming years will be to develop crops that can cope with the consequences of declining freshwater resources and changing temperatures. One approach to meeting this challenge may lie in our understanding of plant photosynthetic adaptations and water use efficiency. Plants from various taxa have evolved crassulacean acid metabolism (CAM), a water-conserving adaptation of photosynthetic carbon dioxide fixation that enables plants to thrive under semi-arid or seasonally drought-prone conditions. Although past research on CAM has led to a better understanding of the inner workings of plant resilience and adaptation to stress, successful introduction of this pathway into C3 or C4 plants has not been reported. The recent revolution in molecular, systems, and synthetic biology, as well as innovations in high-throughput data generation and mining, creates new opportunities to uncover the minimum genetic tool kit required to introduce CAM traits into drought-sensitive crops. Here, we propose four complementary research avenues to uncover this tool kit. First, genomes and computational methods should be used to improve understanding of the nature of variations that drive CAM evolution. Second, single-cell 'omics technologies offer the possibility for in-depth characterization of the mechanisms that trigger environmentally controlled CAM induction. Third, the rapid increase in new 'omics data enables a comprehensive, multimodal exploration of CAM. Finally, the expansion of functional genomics methods is paving the way for integration of CAM into farming systems.
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Affiliation(s)
- Noé Perron
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32608, USA
| | - Matias Kirst
- Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32608, USA; School of Forest, Fisheries and Geomatics Sciences, University of Florida, Gainesville, FL 32603, USA.
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677-1848, USA.
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Winter K, Holtum JAM. Shifting photosynthesis between the fast and slow lane: Facultative CAM and water-deficit stress. JOURNAL OF PLANT PHYSIOLOGY 2024; 294:154185. [PMID: 38373389 DOI: 10.1016/j.jplph.2024.154185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/28/2023] [Accepted: 01/20/2024] [Indexed: 02/21/2024]
Abstract
Five decades ago, the first report of a shift from C3 to CAM (crassulacean acid metabolism) photosynthesis following the imposition of stress was published in this journal. The annual, Mesembryanthemum crystallinum (Aizoaceae), was shown to be a C3 plant when grown under non-saline conditions, and a CAM plant when exposed to high soil salinity. This observation of environmentally triggered CAM eventually led to the introduction of the term facultative CAM, which categorises CAM that is induced or upregulated in response to water-deficit stress and is lost or downregulated when the stress is removed. Reversibility of C3-to-CAM shifts distinguishes stress-driven facultative-CAM responses from purely ontogenetic increases of CAM activity. We briefly review how the understanding of facultative CAM has developed, evaluate the current state of knowledge, and highlight questions of continuing interest. We demonstrate that the long-lived leaves of a perennial facultative-CAM arborescent species, Clusia pratensis, can repeatedly switch between C3 and CAM in response to multiple wet-dry-wet cycles. Undoubtedly, this is a dedicated response to environment, independent of ontogeny. We highlight the potential for engineering facultative CAM into C3 crops to provide a flexible capacity for drought tolerance.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Panama City, Panama.
| | - Joseph A M Holtum
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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Sato R, Kondo Y, Agarie S. The first released available genome of the common ice plant ( Mesembryanthemum crystallinum L.) extended the research region on salt tolerance, C 3-CAM photosynthetic conversion, and halophilism. F1000Res 2024; 12:448. [PMID: 38618020 PMCID: PMC11016173 DOI: 10.12688/f1000research.129958.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/03/2024] [Indexed: 04/16/2024] Open
Abstract
Background The common ice plant ( Mesembryanthemum crystallinum L.) is an annual herb belonging to the genus Mesembryanthemum of the family Aizoaceae, native to Southern Africa. Methods We performed shotgun genome paired-end sequencing using the Illumina platform to determine the genome sequence of the ice plants. We assembled the whole genome sequences using the genome assembler "ALGA" and "Redundans", then released them as available genomic information. Finally, we mainly estimated the potential genomic function by the homology search method. Results A draft genome was generated with a total length of 286 Mb corresponding to 79.2% of the estimated genome size (361 Mb), consisting of 49,782 contigs. It encompassed 93.49% of the genes of terrestrial higher plants, 99.5% of the ice plant transcriptome, and 100% of known DNA sequences. In addition, 110.9 Mb (38.8%) of repetitive sequences and untranslated regions, 971 tRNA, and 100 miRNA loci were identified, and their effects on stress tolerance and photosynthesis were investigated. Molecular phylogenetic analysis based on ribosomal DNA among 26 kinds of plant species revealed genetic similarity between the ice plant and poplar, which have salt tolerance. Overall, 35,702 protein-coding regions were identified in the genome, of which 56.05% to 82.59% were annotated and submitted to domain searches and gene ontology (GO) analyses, which found that eighteen GO terms stood out among five plant species. These terms were related to biological defense, growth, reproduction, transcription, post-transcription, and intermembrane transportation, regarded as one of the fundamental results of using the utilized ice plant genome. Conclusions The information that we characterized is useful for elucidation of the mechanism of growth promotion under salinity and reversible conversion of the photosynthetic type from C3 to Crassulacean Acid Metabolism (CAM).
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Affiliation(s)
- Ryoma Sato
- Graduate school of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka Nishi-ku Fukuoka, 819-0395, Japan
| | - Yuri Kondo
- Graduate school of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka Nishi-ku Fukuoka, 819-0395, Japan
| | - Sakae Agarie
- Faculty of Agriculture, Kyushu University, 744 Motooka Nishi-ku Fukuoka, 819-0395, Japan
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Gilman IS, Smith JAC, Holtum JAM, Sage RF, Silvera K, Winter K, Edwards EJ. The CAM lineages of planet Earth. ANNALS OF BOTANY 2023; 132:627-654. [PMID: 37698538 PMCID: PMC10799995 DOI: 10.1093/aob/mcad135] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/09/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023]
Abstract
BACKGROUND AND SCOPE The growth of experimental studies of crassulacean acid metabolism (CAM) in diverse plant clades, coupled with recent advances in molecular systematics, presents an opportunity to re-assess the phylogenetic distribution and diversity of species capable of CAM. It has been more than two decades since the last comprehensive lists of CAM taxa were published, and an updated survey of the occurrence and distribution of CAM taxa is needed to facilitate and guide future CAM research. We aimed to survey the phylogenetic distribution of these taxa, their diverse morphology, physiology and ecology, and the likely number of evolutionary origins of CAM based on currently known lineages. RESULTS AND CONCLUSIONS We found direct evidence (in the form of experimental or field observations of gas exchange, day-night fluctuations in organic acids, carbon isotope ratios and enzymatic activity) for CAM in 370 genera of vascular plants, representing 38 families. Further assumptions about the frequency of CAM species in CAM clades and the distribution of CAM in the Cactaceae and Crassulaceae bring the currently estimated number of CAM-capable species to nearly 7 % of all vascular plants. The phylogenetic distribution of these taxa suggests a minimum of 66 independent origins of CAM in vascular plants, possibly with dozens more. To achieve further insight into CAM origins, there is a need for more extensive and systematic surveys of previously unstudied lineages, particularly in living material to identify low-level CAM activity, and for denser sampling to increase phylogenetic resolution in CAM-evolving clades. This should allow further progress in understanding the functional significance of this pathway by integration with studies on the evolution and genomics of CAM in its many forms.
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Affiliation(s)
- Ian S Gilman
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
| | | | - Joseph A M Holtum
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Katia Silvera
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panama
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panama
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
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Liu Z, Fu Y, Wang H, Zhang Y, Han J, Wang Y, Shen S, Li C, Jiang M, Yang X, Song X. The high-quality sequencing of the Brassica rapa 'XiangQingCai' genome and exploration of genome evolution and genes related to volatile aroma. HORTICULTURE RESEARCH 2023; 10:uhad187. [PMID: 37899953 PMCID: PMC10611556 DOI: 10.1093/hr/uhad187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 09/08/2023] [Indexed: 10/31/2023]
Abstract
'Vanilla' (XQC, brassica variety chinensis) is an important vegetable crop in the Brassica family, named for its strong volatile fragrance. In this study, we report the high-quality chromosome-level genome sequence of XQC. The assembled genome length was determined as 466.11 Mb, with an N50 scaffold of 46.20 Mb. A total of 59.50% repetitive sequences were detected in the XQC genome, including 47 570 genes. Among all examined Brassicaceae species, XQC had the closest relationship with B. rapa QGC ('QingGengCai') and B. rapa Pakchoi. Two whole-genome duplication (WGD) events and one recent whole-genome triplication (WGT) event occurred in the XQC genome in addition to an ancient WGT event. The recent WGT was observed to occur during 21.59-24.40 Mya (after evolution rate corrections). Our findings indicate that XQC experienced gene losses and chromosome rearrangements during the genome evolution of XQC. The results of the integrated genomic and transcriptomic analyses revealed critical genes involved in the terpenoid biosynthesis pathway and terpene synthase (TPS) family genes. In summary, we determined a chromosome-level genome of B. rapa XQC and identified the key candidate genes involved in volatile fragrance synthesis. This work can act as a basis for the comparative and functional genomic analysis and molecular breeding of B. rapa in the future.
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Affiliation(s)
- Zhaokun Liu
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Yanhong Fu
- College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei 063210, China
| | - Huan Wang
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Yanping Zhang
- Suzhou Polytechnic Institute of Agriculture, Suzhou, Jiangsu 215008, China
| | - Jianjun Han
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Yingying Wang
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Shaoqin Shen
- College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei 063210, China
| | - Chunjin Li
- College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei 063210, China
| | - Mingmin Jiang
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Xuemei Yang
- Suzhou Academy of Agricultural Sciences, Suzhou, Jiangsu 215155, China
| | - Xiaoming Song
- College of Life Sciences, North China University of Science and Technology, Tangshan, Hebei 063210, China
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Meng F, Chu T, Feng P, Li N, Song C, Li C, Leng L, Song X, Chen W. Genome assembly of Polygala tenuifolia provides insights into its karyotype evolution and triterpenoid saponin biosynthesis. HORTICULTURE RESEARCH 2023; 10:uhad139. [PMID: 37671073 PMCID: PMC10476160 DOI: 10.1093/hr/uhad139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 07/05/2023] [Indexed: 09/07/2023]
Abstract
Polygala tenuifolia is a perennial medicinal plant that has been widely used in traditional Chinese medicine for treating mental diseases. However, the lack of genomic resources limits the insight into its evolutionary and biological characterization. In the present work, we reported the P. tenuifolia genome, the first genome assembly of the Polygalaceae family. We sequenced and assembled this genome by a combination of Illumnina, PacBio HiFi, and Hi-C mapping. The assembly includes 19 pseudochromosomes covering ~92.68% of the assembled genome (~769.62 Mb). There are 36 463 protein-coding genes annotated in this genome. Detailed comparative genome analysis revealed that P. tenuifolia experienced two rounds of whole genome duplication that occurred ~39-44 and ~18-20 million years ago, respectively. Accordingly, we systematically reconstructed ancestral chromosomes of P. tenuifolia and inferred its chromosome evolution trajectories from the common ancestor of core eudicots to the present species. Based on the transcriptomics data, enzyme genes and transcription factors involved in the synthesis of triterpenoid saponin in P. tenuifolia were identified. Further analysis demonstrated that whole-genome duplications and tandem duplications play critical roles in the expansion of P450 and UGT gene families, which contributed to the synthesis of triterpenoid saponins. The genome and transcriptome data will not only provide valuable resources for comparative and functional genomic researches on Polygalaceae, but also shed light on the synthesis of triterpenoid saponin.
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Affiliation(s)
- Fanbo Meng
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- >State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chengdu University of Traditional Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Tianzhe Chu
- >State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chengdu University of Traditional Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Pengmian Feng
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Nan Li
- School of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Chi Song
- >State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chengdu University of Traditional Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Chunjin Li
- School of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Liang Leng
- >State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chengdu University of Traditional Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- Institute of Herbgenomics, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Xiaoming Song
- School of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
| | - Wei Chen
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Basic Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- >State Key Laboratory of Southwestern Chinese Medicine Resources, Innovative Institute of Chengdu University of Traditional Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
- School of Life Sciences, North China University of Science and Technology, Tangshan 063210, China
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Tan B, Chen S. Defining Mechanisms of C 3 to CAM Photosynthesis Transition toward Enhancing Crop Stress Resilience. Int J Mol Sci 2023; 24:13072. [PMID: 37685878 PMCID: PMC10487458 DOI: 10.3390/ijms241713072] [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: 07/03/2023] [Revised: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 09/10/2023] Open
Abstract
Global climate change and population growth are persistently posing threats to natural resources (e.g., freshwater) and agricultural production. Crassulacean acid metabolism (CAM) evolved from C3 photosynthesis as an adaptive form of photosynthesis in hot and arid regions. It features the nocturnal opening of stomata for CO2 assimilation, diurnal closure of stomata for water conservation, and high water-use efficiency. To cope with global climate challenges, the CAM mechanism has attracted renewed attention. Facultative CAM is a specialized form of CAM that normally employs C3 or C4 photosynthesis but can shift to CAM under stress conditions. It not only serves as a model for studying the molecular mechanisms underlying the CAM evolution, but also provides a plausible solution for creating stress-resilient crops with facultative CAM traits. This review mainly discusses the recent research effort in defining the C3 to CAM transition of facultative CAM plants, and highlights challenges and future directions in this important research area with great application potential.
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Affiliation(s)
| | - Sixue Chen
- Department of Biology, University of Mississippi, Oxford, MS 38677, USA;
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10
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Wang P, Wang F. A proposed metric set for evaluation of genome assembly quality. Trends Genet 2023; 39:175-186. [PMID: 36402623 DOI: 10.1016/j.tig.2022.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/18/2022]
Abstract
Quality control is essential for genome assemblies; however, a consensus has yet to be reached on what metrics should be adopted for the evaluation of assembly quality. N50 is widely used for contiguity measurement, but its effectiveness is constantly in question. Prevailing metrics for the completeness evaluation focus on gene space, yet challenging areas such as tandem repeats are commonly overlooked. Achieving correctness has become an indispensable dimension for quality control, while prevailing assembly releases lack scores reflecting this aspect. We propose a metric set with a set of statistic indexes for effective, comprehensive evaluation of assemblies and provide a score of a finished assembly for each metric, which can be utilized as a benchmark for achieving high-quality genome assemblies.
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Affiliation(s)
- Peng Wang
- Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China, Ministry of Agriculture and Rural Affairs, Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agricultural Sciences, No. 4 Xueyuan Rd, Haikou City, Hainan 571101, China.
| | - Fei Wang
- School of Electrical and Electronic Engineering, Shanghai Institute of Technology, No. 100 Haiquan Rd, Shanghai 201416, China.
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