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Xu Y, Hu R, Li S. Regulation of seed coat mucilage production and modification in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 328:111591. [PMID: 36623642 DOI: 10.1016/j.plantsci.2023.111591] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/13/2022] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
The Arabidopsis seed coat mucilage is a polysaccharide-rich matrix synthesized by the seed coat epidermal cells. It is a specialized cell wall mainly composed of three types of polysaccharides (i. e. pectin, hemicellulose, and cellulose), and represents as an ideal model system for plant cell wall research. A large number of genes responsible for the synthesis and modification of cell wall polysaccharides have been identified using this model system. Moreover, a subset of regulators controlling mucilage production and modification have been characterized, and the underlying transcriptional regulatory mechanisms have been elucidated. This substantially contributes to the understanding of the molecular mechanisms underlying mucilage synthesis and modification. In this review, we concisely summarize the various genes and regulators involved in seed coat cell differentiation, mucilage biosynthesis and modification, and secondary cell wall formation. In particular, we put emphasis on the latest knowledge gained regarding the transcriptional regulation of mucilage production, which is composed of a hierarchal cascade with three-layer transcriptional regulators. Collectively, we propose an updated schematic framework of the genetic regulatory network controlling mucilage production and modification in the Arabidopsis mucilage secretory cells.
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Affiliation(s)
- Yan Xu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China
| | - Ruibo Hu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China.
| | - Shengjun Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, PR China; Shandong Energy Institute, Qingdao 266101, PR China; Qingdao New Energy Shandong Laboratory, Qingdao 266101, PR China.
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Zhao S, Nie X, Liu X, Wang B, Liu S, Qin L, Xing Y. Genome-Wide Identification of the CER Gene Family and Significant Features in Climate Adaptation of Castanea mollissima. Int J Mol Sci 2022; 23:ijms232416202. [PMID: 36555843 PMCID: PMC9787725 DOI: 10.3390/ijms232416202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
The plant cuticle is the outermost layer of the aerial organs and an important barrier against biotic and abiotic stresses. The climate varies greatly between the north and south of China, with large differences in temperature and humidity, but Chinese chestnut is found in both regions. This study investigated the relationship between the wax layer of chestnut leaves and environmental adaptation. Firstly, semi-thin sections were used to verify that there is a significant difference in the thickness of the epicuticular wax layer between wild chestnut leaves in northwest and southeast China. Secondly, a whole-genome selective sweep was used to resequence wild chestnut samples from two typical regional populations, and significant genetic divergence was identified between the two populations in the CmCER1-1, CmCER1-5 and CmCER3 genes. Thirty-four CER genes were identified in the whole chestnut genome, and a series of predictive analyses were performed on the identified CmCER genes. The expression patterns of CmCER genes were classified into three trends-upregulation, upregulation followed by downregulation and continuous downregulation-when chestnut seedlings were treated with drought stress. Analysis of cultivars from two resource beds in Beijing and Liyang showed that the wax layer of the northern variety was thicker than that of the southern variety. For the Y-2 (Castanea mollissima genome sequencing material) cultivar, there were significant differences in the expression of CmCER1-1, CmCER1-5 and CmCER3 between the southern variety and the northern one-year-grafted variety. Therefore, this study suggests that the CER family genes play a role in environmental adaptations in chestnut, laying the foundation for further exploration of CmCER genes. It also demonstrates the importance of studying the adaptation of Chinese chestnut wax biosynthesis to the southern and northern environments.
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Affiliation(s)
| | | | | | | | | | - Ling Qin
- Correspondence: (L.Q.); (Y.X.); Tel.: +86-10-8079-7229 (Y.X.)
| | - Yu Xing
- Correspondence: (L.Q.); (Y.X.); Tel.: +86-10-8079-7229 (Y.X.)
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Ichino T, Yazaki K. Modes of secretion of plant lipophilic metabolites via ABCG transporter-dependent transport and vesicle-mediated trafficking. CURRENT OPINION IN PLANT BIOLOGY 2022; 66:102184. [PMID: 35217474 DOI: 10.1016/j.pbi.2022.102184] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/27/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Many lipophilic metabolites produced by terrestrial plants are deposited on plant surfaces to protect them from abiotic and biotic stresses. Plant-derived lipophilic metabolites include apoplastic biopolymers, such as wax, cutin, sporopollenin, suberin, and lignin, as well as low-molecular-weight secondary metabolites. These secreted molecules confer adaptive toughness and robustness on plants. The mechanisms responsible for the secretion of these lipophilic metabolites remain unclear, although two pathways, mediated by transporters and vesicles, have been proposed. Recent genetic and biochemical studies have shown that G-type ATP-binding cassette (ABCG) transporters and membrane trafficking factors are involved in the apoplastic accumulation of lipophilic metabolites in plants. These two distinctive modes of secretion may be either exclusive or collaborative. This review describes these transporter-dependent and vesicle-mediated mechanisms underlying the secretion of lipophilic metabolites.
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Affiliation(s)
- Takuji Ichino
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, 611-0011, Japan
| | - Kazufumi Yazaki
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, 611-0011, Japan.
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Wang C, Xiang Y, Qian D. Current progress in plant V-ATPase: From biochemical properties to physiological functions. JOURNAL OF PLANT PHYSIOLOGY 2021; 266:153525. [PMID: 34560396 DOI: 10.1016/j.jplph.2021.153525] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/12/2021] [Accepted: 09/12/2021] [Indexed: 06/13/2023]
Abstract
Vacuolar-type adenosine triphosphatase (V-ATPase, VHA) is a highly conserved, ATP-driven multisubunit proton pump that is widely distributed in all eukaryotic cells. V-ATPase consists of two domains formed by at least 13 different subunits, the membrane peripheral V1 domain responsible for ATP hydrolysis, and the membrane-integral V0 domain responsible for proton translocation. V-ATPase plays an essential role in energizing secondary active transport and is indispensable to plants. In addition to multiple stress responses, plant V-ATPase is also implicated in physiological processes such as growth, development, and morphogenesis. Based on the identification of distinct V-ATPase mutants and advances in luminal pH measurements in vivo, it has been revealed that this holoenzyme complex plays a pivotal role in pH homeostasis of the plant endomembrane system and endocytic and secretory trafficking. Here, we review recent progress in comprehending the biochemical properties and physiological functions of plant V-ATPase and explore the topics that require further elucidation.
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Affiliation(s)
- Chao Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Yun Xiang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Dong Qian
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
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Lee Y, Dean GH, Gilchrist E, Tsai AY, Haughn GW. Asymmetric distribution of extracellular matrix proteins in seed coat epidermal cells of Arabidopsis is determined by polar secretion. PLANT DIRECT 2021; 5:e360. [PMID: 34877448 PMCID: PMC8628086 DOI: 10.1002/pld3.360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/18/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
Although asymmetric deposition of the plant extracellular matrix is critical for the normal functioning of many cell types, the molecular mechanisms establishing this asymmetry are not well understood. During differentiation, Arabidopsis seed coat epidermal cells deposit large amounts of pectin-rich mucilage asymmetrically to form an extracellular pocket between the plasma membrane and the outer tangential primary cell wall. At maturity, the mucilage expands on contact with water, ruptures the primary cell wall, and extrudes to encapsulate the seed. In addition to polysaccharides, mucilage contains secreted proteins including the β-galactosidase MUCILAGE MODIFIED 2 (MUM2). A functional chimeric protein where MUM2 was fused translationally with Citrine yellow fluorescent protein (Citrine) indicated that MUM2-Citrine fluorescence preferentially accumulates in the mucilage pocket concomitant with mucilage deposition and rapidly disappears when mucilage synthesis ceases. A secreted form of Citrine, secCitrine, showed a similar pattern of localization when expressed in developing seed coat epidermal cells. This result suggested that both the asymmetric localization and rapid decrease of fluorescence is not unique to MUM2-Citrine and may represent the default pathway for secreted proteins in this cell type. v-SNARE proteins were localized only in the membrane adjacent to the mucilage pocket, supporting the hypothesis that the cellular secretory apparatus is redirected and targets secretion to the outer periclinal apoplast during mucilage synthesis. In addition, mutation of ECHIDNA, a gene encoding a TGN-localized protein involved in vesicle targeting, causes misdirection of mucilage, MUM2 and v-SNARE proteins from the apoplast/plasma membrane to the vacuole/tonoplast. Western blot analyses suggested that the disappearance of MUM2-Citrine fluorescence at the end of mucilage synthesis is due to protein degradation and because several proteases have been identified in extruded seed mucilage. However, as mutation of these genes did not result in a substantial delay in MUM2-Citrine degradation and the timing of their expression and/or their intracellular localization were not consistent with a role in MUM2-Citrine disappearance, the mechanism underlying the abrupt decrease of MUM2-Citrine remains unclear.
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Affiliation(s)
- Yi‐Chen Lee
- Department of BotanyUniversity of British ColumbiaVancouverCanada
- Present address:
Biodiversity Research CenterAcademia SinicaTaipeiTaiwan
| | - Gillian H. Dean
- Department of BotanyUniversity of British ColumbiaVancouverCanada
| | - Erin Gilchrist
- Department of BotanyUniversity of British ColumbiaVancouverCanada
- Present address:
Molecular DiagnosticsAnandia LaboratoriesVancouverCanada
| | - Allen Yi‐Lun Tsai
- Department of BotanyUniversity of British ColumbiaVancouverCanada
- Present address:
International Research Center for Agricultural & Environmental Biology, Faculty of Advanced Science and TechnologyKumamoto UniversityKumamotoJapan
| | - George W. Haughn
- Department of BotanyUniversity of British ColumbiaVancouverCanada
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Network Analysis Prioritizes DEWAX and ICE1 as the Candidate Genes for Major eQTL Hotspots in Seed Germination of Arabidopsis thaliana. G3-GENES GENOMES GENETICS 2020; 10:4215-4226. [PMID: 32963085 PMCID: PMC7642920 DOI: 10.1534/g3.120.401477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Seed germination is characterized by a constant change of gene expression across different time points. These changes are related to specific processes, which eventually determine the onset of seed germination. To get a better understanding on the regulation of gene expression during seed germination, we performed a quantitative trait locus mapping of gene expression (eQTL) at four important seed germination stages (primary dormant, after-ripened, six-hour after imbibition, and radicle protrusion stage) using Arabidopsis thaliana Bay x Sha recombinant inbred lines (RILs). The mapping displayed the distinctness of the eQTL landscape for each stage. We found several eQTL hotspots across stages associated with the regulation of expression of a large number of genes. Interestingly, an eQTL hotspot on chromosome five collocates with hotspots for phenotypic and metabolic QTL in the same population. Finally, we constructed a gene co-expression network to prioritize the regulatory genes for two major eQTL hotspots. The network analysis prioritizes transcription factors DEWAX and ICE1 as the most likely regulatory genes for the hotspot. Together, we have revealed that the genetic regulation of gene expression is dynamic along the course of seed germination.
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Lou L, Ding L, Wang T, Xiang Y. Emerging Roles of RNA-Binding Proteins in Seed Development and Performance. Int J Mol Sci 2020; 21:ijms21186822. [PMID: 32957608 PMCID: PMC7555721 DOI: 10.3390/ijms21186822] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/10/2020] [Accepted: 09/10/2020] [Indexed: 02/01/2023] Open
Abstract
Seed development, dormancy, and germination are key physiological events that are not only important for seed generation, survival, and dispersal, but also contribute to agricultural production. RNA-binding proteins (RBPs) directly interact with target mRNAs and fine-tune mRNA metabolism by governing post-transcriptional regulation, including RNA processing, intron splicing, nuclear export, trafficking, stability/decay, and translational control. Recent studies have functionally characterized increasing numbers of diverse RBPs and shown that they participate in seed development and performance, providing significant insight into the role of RBP-mRNA interactions in seed processes. In this review, we discuss recent research progress on newly defined RBPs that have crucial roles in RNA metabolism and affect seed development, dormancy, and germination.
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Zhong MS, Jiang H, Cao Y, Wang YX, You CX, Li YY, Hao YJ. MdCER2 conferred to wax accumulation and increased drought tolerance in plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 149:277-285. [PMID: 32088579 DOI: 10.1016/j.plaphy.2020.02.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 05/08/2023]
Abstract
Drought can activate many stress responses in plant growth and development, including the synthesis of epidermal wax and the induction of abscisic acid (ABA), and increased wax accumulation will improve plant drought resistance. Therefore, an examination of wax biosynthesis genes could help to better understand the molecular mechanism of environmental factors regulating wax biosynthesis and the wax associated stress response. Here, we identified the MdCER2 gene from the 'Gala' (Malus× domestica Borkh.) variety of domestic apple, which is a homolog of Arabidopsis AtCER2. It possesses a transferase domain and the protein localizes on the cell membrane. The MdCER2 gene was constitutively expressed in apple tissues and was induced by drought treatment. Finally, we transformed the MdCER2 gene into Arabidopsis to identify its function, and found ectopic expression of MdCER2 promoted accumulation of cuticular wax in both leaves and stems, decreased water loss and permeability in leaves, increased lateral root number, changed plant ABA sensitivity, and increased drought resistance.
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Affiliation(s)
- Ming-Shuang Zhong
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
| | - Han Jiang
- State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Yue Cao
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
| | - Yong-Xu Wang
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
| | - Chun-Xiang You
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
| | - Yuan-Yuan Li
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
| | - Yu-Jin Hao
- National Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, 271018, China.
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Dean GH, Sola K, Unda F, Mansfield SD, Haughn GW. Analysis of Monosaccharides from Arabidopsis Seed Mucilageand Whole Seeds Using HPAEC-PAD. Bio Protoc 2019; 9:e3464. [PMID: 33654956 DOI: 10.21769/bioprotoc.3464] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 11/11/2019] [Accepted: 11/30/2019] [Indexed: 11/02/2022] Open
Abstract
Arabidopsis seed coat epidermal cells deposit a significant quantity of mucilage, composed of the cell wall components pectin, hemicellulose, and cellulose, into the apoplast during development. When mature seeds are hydrated, mucilage extrudes to form a gelatinous capsule around the seed. Determining the monosaccharide composition of both extruded mucilage and whole seeds is an essential technique for characterizing seed coat developmental processes and mutants with altered mucilage composition. This protocol covers growth of plants to produce seeds suitable for analysis, extraction of extruded mucilage using water and sodium carbonate (used for mutants with impaired mucilage release), and extraction of alcohol insoluble residue (AIR) from whole seeds. The prepared polysaccharides are then hydrolyzed using sulfuric acid, which hydrolyses all polysaccharides including cellulose. Sensitive and reproducible quantification of the resulting monosaccharides is achieved using high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD).
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Affiliation(s)
- Gillian H Dean
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Kresimir Sola
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Faride Unda
- Department of Wood Science, University of British Columbia, Vancouver, Canada
| | - Shawn D Mansfield
- Department of Wood Science, University of British Columbia, Vancouver, Canada
| | - George W Haughn
- Department of Botany, University of British Columbia, Vancouver, Canada
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