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Imaging the Cytoskeleton in Living Plant Roots. Methods Mol Biol 2021; 2364:139-148. [PMID: 34542851 DOI: 10.1007/978-1-0716-1661-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
For the past two decades, genetically encoded fluorescent proteins have emerged as the most popular method to image the plant cytoskeleton. Because fluorescent protein technology involves handling living plant cells, it is important to implement protocols that enable these delicate plant specimens to maintain optimal growth for the entire duration of the imaging experiment. To this end, we rely on a system that consists of a large coverslip coated with nutrient-supplemented agar. This agar-coverslip system is planted with surface-sterilized Arabidopsis thaliana seeds expressing cytoskeletal fluorescent protein reporters. The agar-coverslip system with planted seeds is then maintained in an environmentally controlled growth chamber. The entire setup is transferred onto the stage of a confocal microscope for imaging when roots of germinated seedlings reach a desired length. For plants with larger roots such as Medicago truncatula, the polymerized nutrient-supplemented agar is gently lifted or cut and used to secure pre-germinated seeds on the coverslip prior to root imaging. The agar-coverslip system we use for imaging the cytoskeleton in living roots along with general methods for expressing green fluorescent protein (GFP)-based cytoskeletal reporters in hairy roots of Medicago truncatula is described here.
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Champeyroux C, Stoof C, Rodriguez-Villalon A. Signaling phospholipids in plant development: small couriers determining cell fate. CURRENT OPINION IN PLANT BIOLOGY 2020; 57:61-71. [PMID: 32771964 DOI: 10.1016/j.pbi.2020.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/24/2020] [Accepted: 05/23/2020] [Indexed: 05/25/2023]
Abstract
The survival of plants hinges on their ability to perceive various environmental stimuli and translate them into appropriate biochemical responses. Phospholipids, a class of membrane lipid compounds that are asymmetrically distributed within plant cells, stand out among signal transmitters for their diversity of mechanisms by which they modulate stress and developmental processes. By modifying the chemo-physical properties of the plasma membrane (PM) as well as vesicle trafficking, phospholipids contribute to changes in the protein membrane landscape, and hence, signaling responses. In this article, we review the distinct signaling mechanisms phospholipids are involved in, with a special focus on the nuclear role of these compounds. Additionally, we summarize exemplary developmental processes greatly influenced by phospholipids.
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Affiliation(s)
- Chloe Champeyroux
- Group of Plant Vascular Development, Swiss Federal Institute of Technology (ETH) Zurich, 8092 Zurich, Switzerland
| | - Claudia Stoof
- Group of Plant Vascular Development, Swiss Federal Institute of Technology (ETH) Zurich, 8092 Zurich, Switzerland
| | - Antia Rodriguez-Villalon
- Group of Plant Vascular Development, Swiss Federal Institute of Technology (ETH) Zurich, 8092 Zurich, Switzerland.
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Takatsuka H, Ito M. Cytoskeletal Control of Planar Polarity in Root Hair Development. FRONTIERS IN PLANT SCIENCE 2020; 11:580935. [PMID: 33014003 PMCID: PMC7496891 DOI: 10.3389/fpls.2020.580935] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/19/2020] [Indexed: 05/29/2023]
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Ibrahim A, Yang X, Liu C, Cooper KD, Bishop BA, Zhu M, Kwon S, Schoelz JE, Nelson RS. Plant SNAREs SYP22 and SYP23 interact with Tobacco mosaic virus 126 kDa protein and SYP2s are required for normal local virus accumulation and spread. Virology 2020; 547:57-71. [PMID: 32560905 DOI: 10.1016/j.virol.2020.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/18/2020] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Abstract
Viral proteins often interact with multiple host proteins during virus accumulation and spread. Identities and functions of all interacting host proteins are not known. Through a yeast two-hybrid screen an Arabidopsis thaliana Qa-SNARE protein [syntaxin of plants 23 (AtSYP23)], associated with pre-vacuolar compartment and vacuolar membrane fusion activities, interacted with Tobacco mosaic virus (TMV) 126 kDa protein, associated with virus accumulation and spread. In planta, AtSYP23 and AtSYP22 each fused with mCherry, co-localized with 126 kDa protein-GFP. Additionally, A. thaliana and Nicotiana benthamiana SYP2 proteins and 126 kDa protein interacted during bimolecular fluorescence complementation analysis. Decreased TMV accumulation in Arabidopsis plants lacking SYP23 and in N. benthamiana plants subjected to virus-induced gene silencing (VIGS) of SYP2 orthologs was observed. Diminished TMV accumulation during VIGS correlated with less intercellular virus spread. The inability to eliminate virus accumulation suggests that SYP2 proteins function redundantly for TMV accumulation, as for plant development.
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Affiliation(s)
- Amr Ibrahim
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA; Department of Nucleic Acid and Protein Structure, Agricultural Genetic Engineering Research Institute, Agricultural Research Center, Giza, Egypt.
| | - Xiaohua Yang
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | - Chengke Liu
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | | | | | - Min Zhu
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | - Soonil Kwon
- Noble Research Institute, LLC, Ardmore, OK, 73401, USA
| | - James E Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA
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Nielsen E. The Small GTPase Superfamily in Plants: A Conserved Regulatory Module with Novel Functions. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:247-272. [PMID: 32442390 DOI: 10.1146/annurev-arplant-112619-025827] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Small GTP-binding proteins represent a highly conserved signaling module in eukaryotes that regulates diverse cellular processes such as signal transduction, cytoskeletal organization and cell polarity, cell proliferation and differentiation, intracellular membrane trafficking and transport vesicle formation, and nucleocytoplasmic transport. These proteins function as molecular switches that cycle between active and inactive states, and this cycle is linked to GTP binding and hydrolysis. In this review, the roles of the plant complement of small GTP-binding proteins in these cellular processes are described, as well as accessory proteins that control their activity, and current understanding of the functions of individual members of these families in plants-with a focus on the model organism Arabidopsis-is presented. Some potential novel roles of these GTPases in plants, relative to their established roles in yeast and/or animal systems, are also discussed.
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Affiliation(s)
- Erik Nielsen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA;
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Arabidopsis ABCG28 is required for the apical accumulation of reactive oxygen species in growing pollen tubes. Proc Natl Acad Sci U S A 2019; 116:12540-12549. [PMID: 31152136 DOI: 10.1073/pnas.1902010116] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Tip-focused accumulation of reactive oxygen species (ROS) is tightly associated with pollen tube growth and is thus critical for fertilization. However, it is unclear how tip-growing cells establish such specific ROS localization. Polyamines have been proposed to function in tip growth as precursors of the ROS, hydrogen peroxide. The ABC transporter AtABCG28 may regulate ROS status, as it contains multiple cysteine residues, a characteristic of proteins involved in ROS homeostasis. In this study, we found that AtABCG28 was specifically expressed in the mature pollen grains and pollen tubes. AtABCG28 was localized to secretory vesicles inside the pollen tube that moved toward and fused with the plasma membrane of the pollen tube tip. Knocking out AtABCG28 resulted in defective pollen tube growth, failure to localize polyamine and ROS to the growing pollen tube tip, and complete male sterility, whereas ectopic expression of this gene in root hair could recover ROS accumulation at the tip and improved the growth under high-pH conditions, which normally prevent ROS accumulation and tip growth. Together, these data suggest that AtABCG28 is critical for localizing polyamine and ROS at the growing tip. In addition, this function of AtABCG28 is likely to protect the pollen tube from the cytotoxicity of polyamine and contribute to the delivery of polyamine to the growing tip for incorporation into the expanding cell wall.
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Chen G, Ye X, Zhang S, Zhu S, Yuan L, Hou J, Wang C. Comparative Transcriptome Analysis between Fertile and CMS Flower Buds in Wucai (Brassica campestris L.). BMC Genomics 2018; 19:908. [PMID: 30541424 PMCID: PMC6292171 DOI: 10.1186/s12864-018-5331-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 11/29/2018] [Indexed: 11/12/2022] Open
Abstract
Background Wucai (Brassica campestris L. ssp. chinensis var. rosularis Tsen) is a variant of nonheading Chinese cabbage (Brassica campestris L.), which is one of the major vegetables in China. Cytoplasmic male sterility (CMS) has been used for Wucai breeding in recent years. However, the underlying molecular mechanism of Wucai CMS remains unclear. In this study, the phenotypic and cytological features of Wucai CMS were observed by anatomical analysis, and a comparative transcriptome analysis was carried out to identify genes related to male sterility using Illumina RNA sequencing technology (RNA-Seq). Results Microscopic observation demonstrated that tapetum development was abnormal in the CMS line, which failed to produce fertile pollen. Bioinformatics analysis detected 4430 differentially expressed genes (DEGs) between the fertile and sterile flower buds. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to better understand the functions of these DEGs. Among the DEGs, 35 genes (53 DEGS) were implicated in anther and pollen development, and 11 genes were involved in pollen cell wall formation and modification; most of these showed downregulated expression in sterile buds. In addition, several genes related to tapetum development (A6, AMS, MS1, MYB39, and TSM1) and a few genes annotated to flowering (CO, AP3, VIN3, FLC, FT, and AGL) were detected and confirmed by qRT-PCR as being expressed at the meiosis, tetrad, and uninucleate microspore stages, thus implying possible roles in specifying or determining the fate and development of the tapetum, male gametophyte and stamen. Moreover, the top four largest transcription factor families (MYB, bHLH, NAC and WRKY) were analyzed, and most showed reduced expression in sterile buds. These differentially expressed transcription factors might result in abortion of pollen development in Wucai. Conclusion The present comparative transcriptome analysis suggested that many key genes and transcription factors involved in anther development show reduced gene expression patterns in the CMS line, which might contribute to male sterility in Wucai. This study provides valuable information for a better understanding of CMS molecular mechanisms and functional genome studies in Wucai. Electronic supplementary material The online version of this article (10.1186/s12864-018-5331-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guohu Chen
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China.,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding, Hefei, 230036, China
| | - Xinyu Ye
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China
| | - Shengyun Zhang
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China
| | - Shidong Zhu
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China.,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding, Hefei, 230036, China
| | - Lingyun Yuan
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China.,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding, Hefei, 230036, China
| | - Jinfeng Hou
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China.,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding, Hefei, 230036, China
| | - Chenggang Wang
- Vegetable Genetics and Breeding Laboratory, College of Horticulture, Anhui Agricultural University, Hefei, 230036, China. .,Anhui Provincial Engineering Laboratory of Horticultural Crop Breeding, Hefei, 230036, China.
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Naramoto S, Kyozuka J. ARF GTPase machinery at the plasma membrane regulates auxin transport-mediated plant growth. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2018; 35:155-159. [PMID: 31819717 PMCID: PMC6879391 DOI: 10.5511/plantbiotechnology.18.0312a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 03/12/2018] [Indexed: 05/23/2023]
Abstract
VAN3 is a plant ACAP-type ADP-ribosylation factor-GTPase activating protein (ARF-GAP) that regulates auxin transport-mediated plant morphogenesis such as continuous venation and lateral root development in Arabidopsis. Previous studies suggested that VAN3 localizes at the plasma membrane (PM) and intracellular structures. However, the role of PM localization in mediating the van3 mutant phenotype is not clear. Here we performed subcellular localization analysis of VAN3 and its regulators CVP2 and VAB to determine their endogenous functions. We found that GFP-tagged CVP2 and VAB preferentially localize at the PM in stably transformed plants. We determined that transgenic plants with lower expression levels of GFP- or mRFP-tagged VAN3 displayed PM localization, which was sufficient to rescue the van3 mutant. Functional VAN3-mRFP and VAB-GFP colocalized at PMs. The van3 mutant phenotype was suppressed by mutation of VAN7/GNOM, which encodes an ARF-GEF that localizes at the PM and Golgi apparatus. These combined results suggest that ARF-GTPase machinery at the PM regulates auxin transport-mediated plant growth and development.
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Affiliation(s)
- Satoshi Naramoto
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Junko Kyozuka
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8577, Japan
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Paez-Garcia A, Sparks JA, de Bang L, Blancaflor EB. Plant Actin Cytoskeleton: New Functions from Old Scaffold. PLANT CELL MONOGRAPHS 2018. [DOI: 10.1007/978-3-319-69944-8_6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Singh MK, Jürgens G. Specificity of plant membrane trafficking - ARFs, regulators and coat proteins. Semin Cell Dev Biol 2017; 80:85-93. [PMID: 29024759 DOI: 10.1016/j.semcdb.2017.10.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 09/29/2017] [Accepted: 10/09/2017] [Indexed: 11/27/2022]
Abstract
Approximately one-third of all eukaryotic proteins are delivered to their destination by trafficking within the endomembrane system. Such cargo proteins are incorporated into forming membrane vesicles on donor compartments and delivered to acceptor compartments by vesicle fusion. How cargo proteins are sorted into forming vesicles is still largely unknown. Here we review the roles of small GTPases of the ARF/SAR1 family, their regulators designated ARF guanine-nucleotide exchange factors (ARF-GEFs) and ARF GTPase-activating proteins (ARF-GAPs) as well as coat protein complexes during membrane vesicle formation. Although conserved across eukaryotes, these four functional groups of proteins display plant-specific modifications in composition, structure and function.
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Affiliation(s)
- Manoj K Singh
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany
| | - Gerd Jürgens
- Centre for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
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