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Xu Z, Yang S, Li C, Xie M, He Y, Chen S, Tang Y, Li D, Wang T, Yang G. Characterization of metallothionein genes from Broussonetia papyrifera: metal binding and heavy metal tolerance mechanisms. BMC Genomics 2024; 25:563. [PMID: 38840042 PMCID: PMC11151532 DOI: 10.1186/s12864-024-10477-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 05/29/2024] [Indexed: 06/07/2024] Open
Abstract
BACKGROUND Broussonetia papyrifera is an economically significant tree with high utilization value, yet its cultivation is often constrained by soil contamination with heavy metals (HMs). Effective scientific cultivation management, which enhances the yield and quality of B. papyrifera, necessitates an understanding of its regulatory mechanisms in response to HM stress. RESULTS Twelve Metallothionein (MT) genes were identified in B. papyrifera. Their open reading frames ranged from 186 to 372 bp, encoding proteins of 61 to 123 amino acids with molecular weights between 15,473.77 and 29,546.96 Da, and theoretical isoelectric points from 5.24 to 5.32. Phylogenetic analysis classified these BpMTs into three subclasses: MT1, MT2, and MT3, with MT2 containing seven members and MT3 only one. The expression of most BpMT genes was inducible by Cd, Mn, Cu, Zn, and abscisic acid (ABA) treatments, particularly BpMT2e, BpMT2d, BpMT2c, and BpMT1c, which showed significant responses and warrant further study. Yeast cells expressing these BpMT genes exhibited enhanced tolerance to Cd, Mn, Cu, and Zn stresses compared to control cells. Yeasts harboring BpMT1c, BpMT2e, and BpMT2d demonstrated higher accumulation of Cd, Cu, Mn, and Zn, suggesting a chelation and binding capacity of BpMTs towards HMs. Site-directed mutagenesis of cysteine (Cys) residues indicated that mutations in the C domain of type 1 BpMT led to increased sensitivity to HMs and reduced HM accumulation in yeast cells; While in type 2 BpMTs, the contribution of N and C domain to HMs' chelation possibly corelated to the quantity of Cys residues. CONCLUSION The BpMT genes are crucial in responding to diverse HM stresses and are involved in ABA signaling. The Cys-rich domains of BpMTs are pivotal for HM tolerance and chelation. This study offers new insights into the structure-function relationships and metal-binding capabilities of type-1 and - 2 plant MTs, enhancing our understanding of their roles in plant adaptation to HM stresses.
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Affiliation(s)
- Zhenggang Xu
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Shen Yang
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Chenhao Li
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Muhong Xie
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Yi He
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Sisi Chen
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Yan Tang
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Dapei Li
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Tianyu Wang
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China
| | - Guiyan Yang
- College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China.
- Labortory of Walnut Research Center, College of Forestry, Northwest A & F University, Yangling, 712100, Shaanxi, China.
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Jobby R, Sarkar M, Bose R, Srivastava S, Suprasanna P. Chromiomics: Chromium detoxification and approaches for engineering tolerance in plants. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 350:123991. [PMID: 38631449 DOI: 10.1016/j.envpol.2024.123991] [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: 01/17/2024] [Revised: 04/03/2024] [Accepted: 04/14/2024] [Indexed: 04/19/2024]
Abstract
Chromium (Cr) is a heavy metal that poses a grave threat to the ecosystem including plants. Chromium is very harmful to plants due to its effects on many physiological and metabolic pathways culminating in a negative impact on plant's growth, development, and ability to take up nutrients. Plants have developed physiological, biochemical, and molecular ways of defense against Cr, such as by augmenting antioxidant potential to reduce reactive oxygen species (ROS). A number of genes have been discovered to play a significant role in the defense mechanisms of plants against Cr, for example, genes associated with the activation of phytochelatins, metallothioneins, and those of enzymes like glutathione-S-transferases. Along with this, a few miRNAs have been found to be associated in alleviating Cr stress and, to augment plant tolerance by controlling transcription factors, HSPs, and the expression of a few proteins and hormones. Defense pathway genes and miRNAs have been used for the generation of transgenic phytoremediator plants. Not only do the transgenic plants have a higher tolerance to Cr, but they also act as hyperaccumulators for Cr and have the potential to remediate other heavy metals. This article describes about environmental Cr contamination, Cr effects on plants, different genes and miRNAs involved in Cr stress mitigation and use of candidate genes, microRNAs for creating transgenic plant systems for phytoremediation, and the applications of CRISPR technology. It is expected that the integration of omics approach and advanced genomics will offer scope for more effective phytoremediation of Chromium in the coming years.
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Affiliation(s)
- Renitta Jobby
- Amity Institute of Biotechnology, Amity University, Maharashtra - Pune Expressway, Bhatan, Panvel, Maharashtra 410206, India; Amity Centre of Excellence in Astrobiology, Amity University Maharashtra - Pune Expressway, Bhatan, Panvel, Mumbai, Maharashtra 410206, India
| | - Mrittika Sarkar
- Amity Institute of Biotechnology, Amity University, Maharashtra - Pune Expressway, Bhatan, Panvel, Maharashtra 410206, India
| | - Roshnee Bose
- Amity Institute of Biotechnology, Amity University, Maharashtra - Pune Expressway, Bhatan, Panvel, Maharashtra 410206, India
| | - Sudhakar Srivastava
- Institute of Environment & Sustainable Development, Banaras Hindu University, Varanasi-221005, India
| | - Penna Suprasanna
- Amity Institute of Biotechnology, Amity University, Maharashtra - Pune Expressway, Bhatan, Panvel, Maharashtra 410206, India; Amity Centre for Nuclear Biotechnology, Amity University, Maharashtra - Pune Expressway, Bhatan, Panvel, Maharashtra 410206, India.
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Joy A, Biswas R. Significance of the Disulfide Bridge in the Structure and Stability of Metalloprotein Azurin. J Phys Chem B 2024; 128:973-984. [PMID: 38236012 DOI: 10.1021/acs.jpcb.3c07089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Metalloproteins make up a class of proteins that incorporate metal ions into their structures, enabling them to perform essential functions in biological systems, such as catalysis and electron transport. Azurin is one such metalloprotein with copper cofactor, having a β-barrel structure with exceptional thermal stability. The copper metal ion is coordinated at one end of the β-barrel structure, and there is a disulfide bond at the opposite end. In this study, we explore the effect of this disulfide bond in the high thermal stability of azurin by analyzing both the native S-S bonded and S-S nonbonded (S-S open) forms using temperature replica exchange molecular dynamics (REMD). Similar to experimental observations, we find a 35 K decrease in denaturation temperature for S-S open azurin compared to that of the native holo form (420 K). As observed in the case of native holo azurin, the unfolding process of the S-S open form also started with disruptions of the α-helix. The free energy surfaces of the unfolding process revealed that the denaturation event of the S-S open form progresses through different sets of conformational ensembles. Subsequently, we compared the stabilities of individual β-sheet strands of both the S-S bonded and the S-S nonbonded forms of azurin. Further, we examined the contacts between individual residues for the central structures from the free energy surfaces of the S-S nonbonded form. The microscopic origin of the lowering in the denaturation temperature is further supplemented by thermodynamic analysis.
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Affiliation(s)
- Albin Joy
- Department of Chemistry, Indian Institute of Technology Tirupati, Yerpedu, Tirupati, Andhra Pradesh, India 517619
| | - Rajib Biswas
- Department of Chemistry, Indian Institute of Technology Tirupati, Yerpedu, Tirupati, Andhra Pradesh, India 517619
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Konieczna W, Mierek-Adamska A, Chojnacka N, Antoszewski M, Szydłowska-Czerniak A, Dąbrowska GB. Characterization of the Metallothionein Gene Family in Avena sativa L. and the Gene Expression during Seed Germination and Heavy Metal Stress. Antioxidants (Basel) 2023; 12:1865. [PMID: 37891944 PMCID: PMC10603854 DOI: 10.3390/antiox12101865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Metallothioneins (MTs) are a family of small proteins rich in cysteine residues. The sulfhydryl group of metallothioneins can bind to metal ions, maintaining metal homeostasis and protecting the cells from damage caused by toxic heavy metals. Moreover, MTs can function as reactive oxygen species scavengers since cysteine thiols undergo reversible and irreversible oxidation. Here, we identified 21 metallothionein genes (AsMTs) in the oat (Avena sativa L.) genome, which were divided into four types depending on the amino acid sequences of putative proteins encoded by identified genes. Analysis of promoter sequences showed that MTs might respond to a variety of stimuli, including biotic and abiotic stresses and phytohormones. The results of qRT-PCR showed that all four types of AsMTs are differentially expressed during the first 48 hours of seed germination. Moreover, stress induced by the application of zinc, cadmium, and a mixture of zinc and cadmium affects the expression of oat MTs variously depending on the MT type, indicating that AsMT1-4 fulfil different roles in plant cells.
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Affiliation(s)
- Wiktoria Konieczna
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Agnieszka Mierek-Adamska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Natalia Chojnacka
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Marcel Antoszewski
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Aleksandra Szydłowska-Czerniak
- Department of Analytical Chemistry and Applied Spectroscopy, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland;
| | - Grażyna B. Dąbrowska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
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Abstract
Metal cofactors are critical centers for different biochemical processes of metalloproteins, and often, this metal coordination renders additional structural stability. In this study, we explore the additional stability conferred by the copper ion on azurin by analyzing both the apo and holo forms using temperature replica exchange molecular dynamics (REMD) data. We find a 14 K decrease in denaturation temperature for apo (406 K) azurin relative to that of holo (420 K), indicating a copper ion-induced additional thermal stability for holo azurin. The unfolding of apo azurin begins with the melting of α-helix and β-sheet V, similar to that of holo form. β-Sheets IV, VII, and VIII are comparatively more stable than other β-strands and melt at higher temperatures. Similar to holo azurin, the strong hydrophobic interactions among the apolar residues in the protein core is the key factor that renders high stability to apo protein as well. We construct free energy surfaces at different temperatures to capture the major conformations along the unfolding basins of the protein. Using contact maps from different basins we show the changes in the interaction between different residues along the unfolding pathway. Furthermore, we compare the Cα root-mean-square fluctuations (Cα-RMSF) and B-factor of all residues of apo and holo forms to understand the flexibility of different regions. The concerted displacement of α-helix and β-sheets V and VI from the protein core is another distinction we observe for apo compared to the holo form, where β-sheet VI was relatively stable.
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Affiliation(s)
- Albin Joy
- Department of Chemistry, Indian Institute of Technology Tirupati, Yerpedu 517619, Andhra Pradesh, India
| | - Rajib Biswas
- Department of Chemistry and Center for Atomic, Molecular and Optical Sciences & Technologies, Indian Institute of Technology Tirupati, Yerpedu 517619, Andhra Pradesh, India
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Zhao J, Xie R, Lin J, Xu L, Gao X, Lin X, Tian S, Lu L. SaMT3 in Sedum alfredii drives Cd detoxification by chelation and ROS-scavenging via Cys residues. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 315:120410. [PMID: 36240968 DOI: 10.1016/j.envpol.2022.120410] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Metallothioneins (MTs), a group of cysteine-rich proteins, are effective chelators of cadmium (Cd) and play a key role in plant Cd detoxification. However, little is known about the role of single cysteine (Cys) residues in the MTs involved in the adaptation of plants to Cd stress, especially, in hyperaccumulators. In the present study, we functionally characterised SaMT3 in S. alfredii, a Cd/Zn hyperaccumulator native to China. Our results showed that the C- and N- terminal regions of SaMT3 had differential functional natures in S. alfredii and determined its Cd hypertolerance and detoxification. Two CXC motifs within the C-terminal region were revealed to play a crucial role in Cd sensing and binding, whereas the four Cys-residues within the N-terminal region were involved in scavenging reactive oxygen species (ROS). An S. alfredii transgenic system based on callus transformation was developed to further investigate the in-planta gene function. The SaMT3-overexpressing transgenic plant roots were more tolerant to Cd than those of wild-type plants. Knockout of SaMT3 resulted in significantly decreased Cd concentrations and increased ROS levels after exposure to Cd stress. We demonstrated the SaMT3-mediated adaptation strategy in S. alfredii, which uses metal chelation and ROS scavenging in response to Cd stress. Our results further reveal the molecular mechanisms underlying Cd detoxification in hyperaccumulating plants, as well as the relation between Cys-related motifs and the metal binding properties of MTs. This research provides valuable insights into the functions of SaMT3 in S. alfredii, and improves our understanding of Cd hyperaccumulation in plants.
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Affiliation(s)
- Jianqi Zhao
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Ruohan Xie
- School of Agriculture, Sun Yat-Sen University, Guangzhou, 510275, China.
| | - Jiayu Lin
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Lingling Xu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Xiaoyu Gao
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
| | - Xianyong Lin
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Shengke Tian
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Lingli Lu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
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Zou T, Pu L, Lin R, Mo H, Wang Z, Jian S, Zhang M. Roles of Canavalia rosea metallothioneins in metal tolerance and extreme environmental adaptation to tropical coral reefs. JOURNAL OF PLANT PHYSIOLOGY 2022; 268:153559. [PMID: 34839100 DOI: 10.1016/j.jplph.2021.153559] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 11/08/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Canavalia rosea (Sw.) DC is a perennial twining herb distributed in the semi-arid and saline-alkali areas of coastal regions and has evolved halotolerance. In this study, we present the first comprehensive survey of the metallothionein (MT) gene family in C. rosea. MT proteins belong to a family of low-molecular-weight polypeptides with a high content of cysteine residues, which have an affinity to bind with heavy metal ions. MTs also play important roles in stress responses as reactive oxygen species (ROS) scavengers. A total of six CrMTs were identified in the C. rosea genome and classified into four subgroups by phylogenetic analysis. An analysis of the cis-acting elements revealed that a series of hormone-, stress-, and development-related cis-acting elements were present in the promoter regions of CrMTs. The expression of CrMTs also showed habitat- and environmental stress-regulated patterns in C. rosea. CrMT overexpression in yeast enhanced tolerance to heavy metals and ROS, as well as high osmotic and alkalinity stress, which is consistent with their predicted roles as metal-chelating proteins and ROS scavengers. Our results indicate that the CrMT genes might contribute to the detoxification of plants to metals and provide marked tolerance against abiotic stress. The expression patterns of CrMTs in C. rosea also indicate that CrMTs play important roles in this species' response to extreme environments on tropical islands and reefs, probably by improving the thermotolerance of C. rosea plants.
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Affiliation(s)
- Tao Zou
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China; University of the Chinese Academy of Sciences, Beijing, 100039, China
| | - Lin Pu
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; University of the Chinese Academy of Sciences, Beijing, 100039, China; CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Ruoyi Lin
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; University of the Chinese Academy of Sciences, Beijing, 100039, China; CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Hui Mo
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China; CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Zhengfeng Wang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Shuguang Jian
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Mei Zhang
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China.
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