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Liu Z, Ruonala R, Helariutta Y. Control of phloem unloading and root development. JOURNAL OF PLANT PHYSIOLOGY 2024; 295:154203. [PMID: 38428153 DOI: 10.1016/j.jplph.2024.154203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/16/2024] [Accepted: 02/16/2024] [Indexed: 03/03/2024]
Abstract
Root growth and development need proper carbon partitioning between sources and sinks. Photosynthesis products are unloaded from the phloem and enter the root meristem cell by cell. While sugar transporters play a major role in phloem loading, phloem unloading occurs via the plasmodesmata in growing root tips. The aperture and permeability of plasmodesmata strongly influence symplastic unloading. Recent research has dissected the symplastic path for phloem unloading and identified several genes that regulate phloem unloading in the root. Callose turnover and membrane lipid composition alter the shape of plasmodesmata, allowing fine-tuning to adapt phloem unloading to the environmental and developmental conditions. Unloaded sugars act both as an energy supply and as signals to coordinate root growth and development. Increased knowledge of how phloem unloading is regulated enhances our understanding of carbon allocation in plants. In the future, it may be possible to modulate carbon allocation between sources and sinks in a manner that would contribute to increased plant biomass and carbon fixation.
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Affiliation(s)
- Zixuan Liu
- Organismal and Evolutionary Biology Research Programme, Faculty of Biology and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Raili Ruonala
- Organismal and Evolutionary Biology Research Programme, Faculty of Biology and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ykä Helariutta
- Organismal and Evolutionary Biology Research Programme, Faculty of Biology and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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2
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Bartusch K, Blanco-Touriñán N, Rodriguez-Villalón A, Truernit E. Monitoring Xylem Transport in Arabidopsis thaliana Seedlings Using Fluorescent Dyes. Methods Mol Biol 2024; 2722:3-15. [PMID: 37897596 DOI: 10.1007/978-1-0716-3477-6_1] [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] [Indexed: 10/30/2023]
Abstract
Fluorescent dyes are often used to observe transport mechanisms in plant vascular tissues. However, it has been technically challenging to apply fluorescent dyes on roots to monitor xylem transport in vivo. Here, we present a fast, noninvasive, and high-throughput protocol to monitor xylem transport in seedlings. Using the fluorescent dyes 5(6)-carboxyfluorescein diacetate (CFDA) and Rhodamine WT, we were able to observe xylem transport on a cellular level in Arabidopsis thaliana roots. We describe how to apply these dyes on primary roots of young seedlings, how to monitor root-to-shoot xylem transport, and how to measure xylem transport velocity in roots. Moreover, we show that our protocol can also be applied to lateral roots and grafted seedlings to assess xylem (re)connection. Altogether, these techniques are useful for investigating xylem functionality in diverse experimental setups.
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Affiliation(s)
- Kai Bartusch
- Group of Phloem Development and Function, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland.
| | - Noel Blanco-Touriñán
- Group of Plant Vascular Development, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Antia Rodriguez-Villalón
- Group of Plant Vascular Development, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Elisabeth Truernit
- Group of Phloem Development and Function, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland.
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3
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Rates ADB, Cesarino I. Pour some sugar on me: The diverse functions of phenylpropanoid glycosylation. JOURNAL OF PLANT PHYSIOLOGY 2023; 291:154138. [PMID: 38006622 DOI: 10.1016/j.jplph.2023.154138] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/06/2023] [Indexed: 11/27/2023]
Abstract
The phenylpropanoid metabolism is the source of a vast array of specialized metabolites that play diverse functions in plant growth and development and contribute to all aspects of plant interactions with their surrounding environment. These compounds protect plants from damaging ultraviolet radiation and reactive oxygen species, provide mechanical support for the plants to stand upright, and mediate plant-plant and plant-microorganism communications. The enormous metabolic diversity of phenylpropanoids is further expanded by chemical modifications known as "decorative reactions", including hydroxylation, methylation, glycosylation, and acylation. Among these modifications, glycosylation is the major driving force of phenylpropanoid structural diversification, also contributing to the expansion of their properties. Phenylpropanoid glycosylation is catalyzed by regioselective uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs), whereas glycosyl hydrolases known as β-glucosidases are the major players in deglycosylation. In this article, we review how the glycosylation process affects key physicochemical properties of phenylpropanoids, such as molecular stability and solubility, as well as metabolite compartmentalization/storage and biological activity/toxicity. We also summarize the recent knowledge on the functional implications of glycosylation of different classes of phenylpropanoid compounds. A balance of glycosylation/deglycosylation might represent an essential molecular mechanism to regulate phenylpropanoid homeostasis, allowing plants to dynamically respond to diverse environmental signals.
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Affiliation(s)
- Arthur de Barros Rates
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, 05508-090, São Paulo, Brazil
| | - Igor Cesarino
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, 05508-090, São Paulo, Brazil; Synthetic and Systems Biology Center, InovaUSP, Avenida Professor Lucio Martins Rodrigues 370, 05508-020, São Paulo, Brazil.
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4
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Gao C, Marker SJV, Gundlach C, Poulsen HF, Bohr T, Schulz A. Tracing the opposing assimilate and nutrient flows in live conifer needles. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6677-6691. [PMID: 37668473 DOI: 10.1093/jxb/erad334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/28/2023] [Indexed: 09/06/2023]
Abstract
The vasculature along conifer needles is fundamentally different from that in angiosperm leaves as it contains a unique transfusion tissue inside the bundle sheath. In this study, we used specific tracers to identify the pathway of photoassimilates from mesophyll to phloem, and the opposing pathway of nutrients from xylem to mesophyll. For symplasmic transport we applied esculin to the tip of attached pine needles and followed its movement down the phloem. For apoplasmic transport we let detached needles take up a membrane-impermeable contrast agent and used micro-X-ray computed tomography to map critical water exchange interfaces and domain borders. Microscopy and segmentation of the X-ray data enabled us to render and quantify the functional 3D structure of the water-filled apoplasm and the complementary symplasmic domain. The transfusion tracheid system formed a sponge-like apoplasmic domain that was blocked at the bundle sheath. Transfusion parenchyma cell chains bridged this domain as tortuous symplasmic pathways with strong local anisotropy which, as evidenced by the accumulation of esculin, pointed to the phloem flanks as the preferred phloem-loading path. Simple estimates supported a pivotal role of the bundle sheath, showing that a bidirectional movement of nutrient ions and assimilates is feasible and emphasizing the role of the bundle sheath in nutrient and assimilate exchange.
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Affiliation(s)
- Chen Gao
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Sean J V Marker
- Department of Physics, Technical University of Denmark. Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Carsten Gundlach
- Department of Physics, Technical University of Denmark. Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Henning F Poulsen
- Department of Physics, Technical University of Denmark. Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Tomas Bohr
- Department of Physics, Technical University of Denmark. Fysikvej, 2800 Kgs. Lyngby, Denmark
| | - Alexander Schulz
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
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5
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Shamshoum M, Kuperman OA, Shadmi SK, Itkin M, Malitsky S, Natalio F. 2-NBDG Uptake in Gossypium hirsutum in vitro ovules: exploring tissue-specific accumulation and its impact on hexokinase-mediated glycolysis regulation. FRONTIERS IN PLANT SCIENCE 2023; 14:1242150. [PMID: 37818315 PMCID: PMC10561253 DOI: 10.3389/fpls.2023.1242150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 09/04/2023] [Indexed: 10/12/2023]
Abstract
Fluorescent glucose derivatives are valuable tools as glucose analogs in plant research to explore metabolic pathways, study enzyme activity, and investigate cellular processes related to glucose metabolism and sugar transport. They allow visualization and tracking of glucose uptake, its utilization, and distribution within plant cells and tissues. This study investigates the phenotypic and metabolic impact of the exogenously fed glucose derivative, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose) (2-NBDG) on the fibers of Gossypium hirsutum (Upland cotton) ovule in vitro cultures. The presence of 2-NBDG in the culture medium did not lead to macroscopic morphological alterations in ovule and fiber development or to the acquisition of fluorescence or yellow coloration. Confocal laser scanning microscope imaging and chromatographic analysis of cotton ovules' outer rim cross-sections showed that the 2-NBDG is transported from the extracellular space and accumulated inside some outer integument cells, epidermal cells, and fertilized epidermal cells (fibers), but is not incorporated into the cell walls. Untargeted metabolic profiling of the fibers revealed significant changes in the relative levels of metabolites involved in glycolysis and upregulation of alternative energy-related pathways. To provide biochemical and structural evidence for the observed downregulation of glycolysis pathways in the fibers containing 2-NBDG, kinetics analysis and docking simulations were performed on hexokinase from G. hirsutum (GhHxk). Notably, the catalytic activity of heterologously expressed recombinant active GhHxk exhibited a five-fold decrease in reaction rates compared to D-glucose. Furthermore, GhHxk exhibited a linear kinetic behavior in the presence of 2-NBDG instead of the Michaelis-Menten kinetics found for D-glucose. Docking simulations suggested that 2-NBDG interacts with a distinct binding site of GhHxk9, possibly inducing a conformational change. These results highlight the importance of considering fluorescent glucose derivatives as ready-to-use analogs for tracking glucose-related biological processes. However, a direct comparison between their mode of action and its extrapolation into biochemical considerations should go beyond microscopic inspection and include complementary analytical techniques.
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Affiliation(s)
- Melina Shamshoum
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ofir Aharon Kuperman
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Sapir Korman Shadmi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Maxim Itkin
- Metabolic Profiling Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Malitsky
- Metabolic Profiling Unit, Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Filipe Natalio
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
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6
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Ren Y, Liao S, Xu Y. An update on sugar allocation and accumulation in fruits. PLANT PHYSIOLOGY 2023; 193:888-899. [PMID: 37224524 DOI: 10.1093/plphys/kiad294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/26/2023]
Abstract
Fruit sweetness is determined by the amount and composition of sugars in the edible flesh. The accumulation of sugar is a highly orchestrated process that requires coordination of numerous metabolic enzymes and sugar transporters. This coordination enables partitioning and long-distance translocation of photoassimilates from source tissues to sink organs. In fruit crops, sugars ultimately accumulate in the sink fruit. Whereas tremendous progress has been achieved in understanding the function of individual genes associated with sugar metabolism and sugar transport in non-fruit crops, there is less known about the sugar transporters and metabolic enzymes responsible for sugar accumulation in fruit crop species. This review identifies knowledge gaps and can serve as a foundation for future studies, with comprehensive updates focusing on (1) the physiological roles of the metabolic enzymes and sugar transporters responsible for sugar allocation and partitioning and that contribute to sugar accumulation in fruit crops; and (2) the molecular mechanisms underlying the transcriptional and posttranslational regulation of sugar transport and metabolism. We also provide insights into the challenges and future directions of studies on sugar transporters and metabolic enzymes and name several promising genes that should be targeted with gene editing in the pursuit of optimized sugar allocation and partitioning to enhance sugar accumulation in fruits.
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Affiliation(s)
- Yi Ren
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences (BAAFS), State Key Laboratory of Vegetable Biobreeding, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Shengjin Liao
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences (BAAFS), State Key Laboratory of Vegetable Biobreeding, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
| | - Yong Xu
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences (BAAFS), State Key Laboratory of Vegetable Biobreeding, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing 100097, China
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7
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Kalmbach L, Bourdon M, Belevich I, Safran J, Lemaire A, Heo JO, Otero S, Blob B, Pelloux J, Jokitalo E, Helariutta Y. Putative pectate lyase PLL12 and callose deposition through polar CALS7 are necessary for long-distance phloem transport in Arabidopsis. Curr Biol 2023; 33:926-939.e9. [PMID: 36805125 DOI: 10.1016/j.cub.2023.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/12/2022] [Accepted: 01/19/2023] [Indexed: 02/18/2023]
Abstract
In plants, the phloem distributes photosynthetic products for metabolism and storage over long distances. It relies on specialized cells, the sieve elements, which are enucleated and interconnected through large so-called sieve pores in their adjoining cell walls. Reverse genetics identified PECTATE LYASE-LIKE 12 (PLL12) as critical for plant growth and development. Using genetic complementations, we established that PLL12 is required exclusively late during sieve element differentiation. Structural homology modeling, enzyme inactivation, and overexpression suggest a vital role for PLL12 in sieve-element-specific pectin remodeling. While short distance symplastic diffusion is unaffected, the pll12 mutant is unable to accommodate sustained plant development due to an incapacity to accommodate increasing hydraulic demands on phloem long-distance transport as the plant grows-a defect that is aggravated when combined with another sieve-element-specific mutant callose synthase 7 (cals7). Establishing CALS7 as a specific sieve pore marker, we investigated the subcellular dynamics of callose deposition in the developing sieve plate. Using fluorescent CALS7 then allowed identifying structural defects in pll12 sieve pores that are moderate at the cellular level but become physiologically relevant due to the serial arrangement of sieve elements in the sieve tube. Overall, pectin degradation through PLL12 appears subtle in quantitative terms. We therefore speculate that PLL12 may act as a regulator to locally remove homogalacturonan, thus potentially enabling further extracellular enzymes to access and modify the cell wall during sieve pore maturation.
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Affiliation(s)
- Lothar Kalmbach
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK.
| | - Matthieu Bourdon
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Ilya Belevich
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Josip Safran
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Adrien Lemaire
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Jung-Ok Heo
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Sofia Otero
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Bernhard Blob
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK
| | - Jérôme Pelloux
- UMR INRAE 1158 BioEcoAgro, BIOPI Biologie des Plantes et Innovation, Université de Picardie, 33 Rue St Leu, 80039 Amiens, France
| | - Eija Jokitalo
- Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Ykä Helariutta
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1LR, UK; Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland.
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8
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Cao HR, Peng WT, Nie MM, Bai S, Chen CQ, Liu Q, Guo ZL, Liao H, Chen ZC. Carbon-nitrogen trading in symbiotic nodules depends on magnesium import. Curr Biol 2022; 32:4337-4349.e5. [PMID: 36055239 DOI: 10.1016/j.cub.2022.08.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/22/2022] [Accepted: 08/10/2022] [Indexed: 11/26/2022]
Abstract
Symbiotic nitrogen fixation provides large amounts of nitrogen for global agricultural systems with little environmental or economic costs. The basis of symbiosis is the nutrient exchange occurring between legumes and rhizobia, but key regulators controlling nutrient exchange are largely unknown. Here, we reveal that magnesium (Mg), an important nutrient factor that preferentially accumulates in inner cortical cells of soybean nodules, shows the most positive correlation with nodule carbon (C) import and nitrogen (N) export. We further identified a pair of Mg transporter genes, GmMGT4 and GmMGT5, that are specifically expressed in the nodule cortex, modulating both nodule Mg import and C-N transport processes. The GmMGT4&5-dependent Mg import activates the activity of a plasmodesmata-located β-1,3-glucanase GmBG2 and consequently keeps plasmodesmata permeable for C-N transport in nodule inner cortical cells. Our studies discovered an important regulating pathway for host plants fine-tuning nodule C-N trading to achieve optimal growth, which may be helpful for optimizing nutrient management for soybean production.
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Affiliation(s)
- Hong-Rui Cao
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wen-Ting Peng
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Miao-Miao Nie
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shuang Bai
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chun-Qu Chen
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Qian Liu
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zi-Long Guo
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Hong Liao
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhi-Chang Chen
- Root Biology Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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9
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Losada JM, He Z, Holbrook NM. Sieve tube structural variation in Austrobaileya scandens and its significance for lianescence. PLANT, CELL & ENVIRONMENT 2022; 45:2460-2475. [PMID: 35606891 PMCID: PMC9540405 DOI: 10.1111/pce.14361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 04/15/2022] [Accepted: 04/23/2022] [Indexed: 06/15/2023]
Abstract
Lianas combine large leaf areas with slender stems, features that require an efficient vascular system. The only extant member of the Austrobaileyaceae is an endemic twining liana of the tropical Australian forests with well-known xylem hydraulics, but the vascular phloem continuum aboveground remains understudied. Microscopy analysis across leaf vein orders and stems of Austrobaileya scandens revealed a low foliar xylem:phloem ratio, with isodiametric vascular elements along the midrib, but tapered across vein orders. Sieve plate pore radii increased from 0.08 µm in minor veins to 0.12 µm in the petiole, but only to 0.20 µm at the stem base, tens of metres away. In easily bent searcher branches, phloem conduits have pectin-rich walls and simple plates, whereas in twining stems, conduits were connected through highly angled and densely porated sieve plates. The hydraulic resistance of phloem conduits in the twisted and elongated stems of A. scandens is large compared with trees of similar stature; phloem hydraulic resistance decreases from leaves to stems, consistent with the efficient delivery of photoassimilates from sources under Münch predictions. Sink strength of a continuously growing canopy might be stronger than in self-supporting understory plants, favoring resource allocation to aerial organs and the attainment of vertical stature.
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Affiliation(s)
- Juan M. Losada
- Institute for Mediterranean and Subtropical Horticulture ‘La Mayora’—CSIC—UMAAvda. Dr. Wienberg s/nAlgarrobo‐CostaMálaga29750Spain
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
| | - Zhe He
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
| | - N. Michele Holbrook
- Department of Organismic and Evolutionary BiologyHarvard UniversityCambridgeMassachusettsUSA
- Arnold Arboretum of Harvard UniversityBostonMassachusettsUSA
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10
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Nam H, Gupta A, Nam H, Lee S, Cho HS, Park C, Park S, Park SJ, Hwang I. JULGI-mediated increment in phloem transport capacity relates to fruit yield in tomato. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1533-1545. [PMID: 35478430 PMCID: PMC9342617 DOI: 10.1111/pbi.13831] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 06/14/2023]
Abstract
The continuous growth of the global population and the increase in the amount of arid land has severely constrained agricultural crop production. To solve this problem, many researchers have attempted to increase productivity through the efficient distribution of energy; however, the direct relationship between the plant vasculature, specifically phloem development, and crop yield is not well established. Here, we demonstrate that an optimum increase in phloem-transportation capacity by reducing SIJUL expression leads to improved sink strength in tomato (Solanum lycopersicum L.). SIJUL, a negative regulator of phloem development, suppresses the translation of a positive regulator of phloem development, SlSMXL5. The suppression of SlJUL increases the number of phloem cells and sucrose transport, but only an optimal reduction of SlJUL function greatly enhances sink strength in tomato, improving fruit setting, and yield contents by 37% and 60%, respectively. We show that the increment in phloem cell number confers spare transport capacity. Our results suggest that the control of phloem-transport capacity within the threshold could enhance the commitment of photosynthates to instigate yield improvement.
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Affiliation(s)
- Hoyoung Nam
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Aarti Gupta
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Heejae Nam
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Seungchul Lee
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Hyun Seob Cho
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Chanyoung Park
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Soyoung Park
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
| | - Soon Ju Park
- Division of Biological Sciences and Research Institute for Basic ScienceWonkwang UniversityIksanKorea
| | - Ildoo Hwang
- Department of Life SciencesPOSTECH Biotech CenterPohang University of Science and TechnologyPohangKorea
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11
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Braun DM. Phloem Loading and Unloading of Sucrose: What a Long, Strange Trip from Source to Sink. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:553-584. [PMID: 35171647 DOI: 10.1146/annurev-arplant-070721-083240] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Sucrose is transported from sources (mature leaves) to sinks (importing tissues such as roots, stems, fruits, and seeds) through the phloem tissues in veins. In many herbaceous crop species, sucrose must first be effluxed to the cell wall by a sugar transporter of the SWEET family prior to being taken up into phloem companion cells or sieve elements by a different sugar transporter, called SUT or SUC. The import of sucrose into these cells is termed apoplasmic phloem loading. In sinks, sucrose can similarly exit the phloem apoplasmically or, alternatively, symplasmically through plasmodesmata into connecting parenchyma storage cells. Recent advances describing the regulation and manipulation of sugar transporter expression and activities provide stimulating new insights into sucrose phloem loading in sources and unloading processes in sink tissues. Additionally, new breakthroughs have revealed distinct subpopulations of cells in leaves with different functions pertaining to phloem loading. These and other discoveries in sucrose transport are discussed.
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Affiliation(s)
- David M Braun
- Division of Plant Science and Technology, Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri-Columbia, Columbia, Missouri, USA;
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12
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Nicolas M, Torres-Pérez R, Wahl V, Cruz-Oró E, Rodríguez-Buey ML, Zamarreño AM, Martín-Jouve B, García-Mina JM, Oliveros JC, Prat S, Cubas P. Spatial control of potato tuberization by the TCP transcription factor BRANCHED1b. NATURE PLANTS 2022; 8:281-294. [PMID: 35318445 DOI: 10.1038/s41477-022-01112-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
The control of carbon allocation, storage and usage is critical for plant growth and development and is exploited for both crop food production and CO2 capture. Potato tubers are natural carbon reserves in the form of starch that have evolved to allow propagation and survival over winter. They form from stolons, below ground, where they are protected from adverse environmental conditions and animal foraging. We show that BRANCHED1b (BRC1b) acts as a tuberization repressor in aerial axillary buds, which prevents buds from competing in sink strength with stolons. BRC1b loss of function leads to ectopic production of aerial tubers and reduced underground tuberization. In aerial axillary buds, BRC1b promotes dormancy, abscisic acid responses and a reduced number of plasmodesmata. This limits sucrose accumulation and access of the tuberigen protein SP6A. BRC1b also directly interacts with SP6A and blocks its tuber-inducing activity in aerial nodes. Altogether, these actions help promote tuberization underground.
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Affiliation(s)
- Michael Nicolas
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain.
| | - Rafael Torres-Pérez
- Bioinformatics for Genomics and Proteomics Unit, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Vanessa Wahl
- Department of Metabolic Networks, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Eduard Cruz-Oró
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - María Luisa Rodríguez-Buey
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Angel María Zamarreño
- Department of Environmental Biology, Faculty of Sciences-BIOMA Institute, University of Navarra, Pamplona, Spain
| | - Beatriz Martín-Jouve
- Electron Microscopy Unit, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - José María García-Mina
- Department of Environmental Biology, Faculty of Sciences-BIOMA Institute, University of Navarra, Pamplona, Spain
| | - Juan Carlos Oliveros
- Bioinformatics for Genomics and Proteomics Unit, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
| | - Salomé Prat
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain
- Department of Plant Development and Signal Transduction, Centre for Research in Agricultural Genomics (CRAG-CSIC), Barcelona, Spain
| | - Pilar Cubas
- Plant Molecular Genetics Department, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, Madrid, Spain.
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13
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Phloem iron remodels root development in response to ammonium as the major nitrogen source. Nat Commun 2022; 13:561. [PMID: 35091578 PMCID: PMC8799741 DOI: 10.1038/s41467-022-28261-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 01/10/2022] [Indexed: 01/20/2023] Open
Abstract
Plants use nitrate and ammonium as major nitrogen (N) sources, each affecting root development through different mechanisms. However, the exact signaling pathways involved in root development are poorly understood. Here, we show that, in Arabidopsis thaliana, either disruption of the cell wall-localized ferroxidase LPR2 or a decrease in iron supplementation efficiently alleviates the growth inhibition of primary roots in response to NH4+ as the N source. Further study revealed that, compared with nitrate, ammonium led to excess iron accumulation in the apoplast of phloem in an LPR2-dependent manner. Such an aberrant iron accumulation subsequently causes massive callose deposition in the phloem from a resulting burst of reactive oxygen species, which impairs the function of the phloem. Therefore, ammonium attenuates primary root development by insufficiently allocating sucrose to the growth zone. Our results link phloem iron to root morphology in response to environmental cues.
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14
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Yadav UP, Evers JF, Shaikh MA, Ayre BG. Cotton phloem loads from the apoplast using a single member of its nine-member sucrose transporter gene family. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:848-859. [PMID: 34687198 DOI: 10.1093/jxb/erab461] [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: 04/26/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
Phloem loading and transport are fundamental processes for allocating carbon from source organs to sink tissues. Cotton (Gossypium spp.) has a high sink demand for the cellulosic fibers that grow on the seed coat and for the storage reserves in the developing embryo, along with the demands of new growth in the shoots and roots. Addressing how cotton mobilizes resources from source leaves to sink organs provides insight into processes contributing to fiber and seed yield. Plasmodesmata frequencies between companion cells and flanking parenchyma in minor veins are higher than expected for an apoplastic loader, and cotton's close relatedness to Tilia spp. hints at passive loading. Suc was the only canonical transport sugar in leaves and constituted 87% of 14C-labeled photoassimilate being actively transported. [14C]Suc uptake coupled with autoradiography indicated active [14C]Suc accumulation in minor veins, suggesting Suc loading from the apoplast; esculin, a fluorescent Suc analog, did not accumulate in minor veins. Of the nine sucrose transporter (SUT) genes identified per diploid genome, only GhSUT1-L2 showed appreciable expression in mature leaves, and silencing GhSUT1-L2 yielded phenotypes characteristic of blocked phloem transport. Furthermore, only GhSUT1-L2 cDNA stimulated esculin and [14C]Suc uptake into yeast, and only the GhSUT1-L2 promoter caused uidA (β-glucuronidase) reporter gene expression in minor vein phloem of Arabidopsis thaliana. Collectively, these results argue that apoplastic phloem loading mediated by GhSUT1-L2 is the dominant mode of phloem loading in cotton.
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Affiliation(s)
- Umesh P Yadav
- BioDiscovery Institute, Department of Biological Sciences, University of North Texas, 1155 Union Circle 305220, Denton, TX 76203-5017, USA
| | - John F Evers
- BioDiscovery Institute, Department of Biological Sciences, University of North Texas, 1155 Union Circle 305220, Denton, TX 76203-5017, USA
| | - Mearaj A Shaikh
- BioDiscovery Institute, Department of Biological Sciences, University of North Texas, 1155 Union Circle 305220, Denton, TX 76203-5017, USA
| | - Brian G Ayre
- BioDiscovery Institute, Department of Biological Sciences, University of North Texas, 1155 Union Circle 305220, Denton, TX 76203-5017, USA
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15
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Sankoh AF, Burch-Smith TM. Approaches for investigating plasmodesmata and effective communication. CURRENT OPINION IN PLANT BIOLOGY 2021; 64:102143. [PMID: 34826658 DOI: 10.1016/j.pbi.2021.102143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Plasmodesmata (PD) are integral plant cell wall components that provide routes for intercellular communication, signaling, and resource sharing. They are therefore essential for plant growth and survival. Much effort has been put forth to understand how PD are generated and their structure is refined for function and to determine how they regulate intercellular trafficking. This review provides an overview of some of the approaches that have been used to study PD structure and function, highlighting those that may be more widely adopted to address questions of PD cell biology and function. Extending our focus on the importance of communication, we address how effective communication strategies can increase diversity and accessibility in the research laboratory, focusing on challenges faced by our deaf/hard-of-hearing colleagues, and highlight successful approaches to including them in the research laboratory.
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Affiliation(s)
- Amie F Sankoh
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States.
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16
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McCubbin TJ, Braun DM. Phloem anatomy and function as shaped by the cell wall. JOURNAL OF PLANT PHYSIOLOGY 2021; 266:153526. [PMID: 34555540 DOI: 10.1016/j.jplph.2021.153526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/12/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
The partitioning of assimilated carbon is a complex process that involves the loading, long-distance transport, and subsequent unloading of carbohydrates from source to sink tissues. The network of plumbing that facilitates this coordinated process is the phloem tissue. Our understanding of the physiology of phloem transport has grown tremendously since the modern theory of mass flow was first put forward, aided by the concomitant progress of technology and experimental methodologies. Recent findings have put a renewed emphasis on the underlying anatomy of the phloem, and in particular the important role that cell walls play in enabling the high-pressure flow of photoassimilates through the sieve element. This review will briefly summarize the foundational work in phloem anatomy and highlight recent work exploring the physiology of phloem cell wall structure and mechanics.
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Affiliation(s)
- Tyler J McCubbin
- Division of Plant Science and Technology, Interdisciplinary Plant Group, The Missouri Maize Center, University of Missouri,Columbia, MO, 65211, USA
| | - David M Braun
- Division of Plant Science and Technology, Interdisciplinary Plant Group, The Missouri Maize Center, University of Missouri,Columbia, MO, 65211, USA; Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
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17
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Lehretz GG, Sonnewald S, Sonnewald U. Assimilate highway to sink organs - Physiological consequences of SP6A overexpression in transgenic potato (Solanum tuberosum L.). JOURNAL OF PLANT PHYSIOLOGY 2021; 266:153530. [PMID: 34610522 DOI: 10.1016/j.jplph.2021.153530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/19/2021] [Indexed: 06/13/2023]
Abstract
Leaf/stem-specific overexpression of SP6A, the FLOWERING LOCUS T homolog in potato (Solanum tuberosum), was previously shown to induce tuberization leading to higher tuber numbers and yield under ambient and abiotic stress conditions. In this study, we investigated the mechanism underlying SP6A action. Overexpression of SP6A reduced shoot growth, mainly by inhibition of stem elongation and secondary growth, and by repression of apical bud outgrowth. In contrast, root growth and lateral shoot emergence from basal nodes was promoted. Tracer experiments using the fluorescent sucrose analogue esculin revealed that stems of SP6A overexpressing plants transport assimilates more efficiently to belowground sinks, e.g. roots and tubers, compared to wild-type plants. This was accompanied by a lower level of sucrose leakage from the transport phloem into neighboring parenchyma cells and the inhibition of flower formation. We demonstrate the ability of SP6A to control assimilate allocation to belowground sinks and postulate that selection of beneficial SP6A alleles will enable potato breeding to alter plant architecture and to increase tuber yield under conditions of expected climate change.
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Affiliation(s)
- Günter G Lehretz
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Sophia Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Uwe Sonnewald
- Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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18
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Ray DM, Savage JA. Seasonal changes in temperate woody plant phloem anatomy and physiology: implications for long-distance transport. AOB PLANTS 2021; 13:plab028. [PMID: 34234934 PMCID: PMC8255074 DOI: 10.1093/aobpla/plab028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
Seasonal changes in climate are accompanied by shifts in carbon allocation and phenological changes in woody angiosperms, the timing of which can have broad implications for species distributions, interactions and ecosystem processes. During critical transitions from autumn to winter and winter to spring, physiological and anatomical changes within the phloem could impose a physical limit on the ability of woody angiosperms to transport carbon and signals. There is a paucity of the literature that addresses tree (floral or foliar) phenology, seasonal phloem anatomy and seasonal phloem physiology together, so our knowledge of how carbon transport could fluctuate seasonally, especially in temperate climates is limited. We review phloem phenology focussing on how sieve element anatomy and phloem sap flow could affect carbon availability throughout the year with a focus on winter. To investigate whether flow is possible in the winter, we construct a simple model of phloem sap flow and investigate how changes to the sap concentration, pressure gradient and sieve plate pores could influence flow during the winter. Our model suggests that phloem transport in some species could occur year-round, even in winter, but current methods for measuring all the parameters surrounding phloem sap flow make it difficult to test this hypothesis. We highlight outstanding questions that remain about phloem functionality in the winter and emphasize the need for new methods to address gaps in our knowledge about phloem function.
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Affiliation(s)
- Dustin M Ray
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
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19
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Paterlini A, Dorussen D, Fichtner F, van Rongen M, Delacruz R, Vojnović A, Helariutta Y, Leyser O. Callose accumulation in specific phloem cell types reduces axillary bud growth in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2021; 231:516-523. [PMID: 33864687 DOI: 10.1111/nph.17398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 04/10/2021] [Indexed: 05/08/2023]
Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Delfi Dorussen
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Franziska Fichtner
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
| | - Martin van Rongen
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Ruth Delacruz
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Ana Vojnović
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Yrjö Helariutta
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
- Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland
| | - Ottoline Leyser
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
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20
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de Moliner F, Knox K, Gordon D, Lee M, Tipping WJ, Geddis A, Reinders A, Ward JM, Oparka K, Vendrell M. A Palette of Minimally Tagged Sucrose Analogues for Real-Time Raman Imaging of Intracellular Plant Metabolism. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 133:7715-7720. [PMID: 38505234 PMCID: PMC10946860 DOI: 10.1002/ange.202016802] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Indexed: 12/19/2022]
Abstract
Sucrose is the main saccharide used for long-distance transport in plants and plays an essential role in energy metabolism; however, there are no analogues for real-time imaging in live cells. We have optimised a synthetic approach to prepare sucrose analogues including very small (≈50 Da or less) Raman tags in the fructose moiety. Spectroscopic analysis identified the alkyne-tagged compound 6 as a sucrose analogue recognised by endogenous transporters in live cells and with higher Raman intensity than other sucrose derivatives. Herein, we demonstrate the application of compound 6 as the first optical probe to visualise real-time uptake and intracellular localisation of sucrose in live plant cells using Raman microscopy.
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Affiliation(s)
| | - Kirsten Knox
- Institute of Molecular Plant SciencesThe University of EdinburghUK
| | - Doireann Gordon
- Centre for Inflammation ResearchThe University ofEdinburghUK
| | - Martin Lee
- Cancer Research (UK) Edinburgh CentreThe University of EdinburghUK
| | - William J. Tipping
- EaStCHEM School of ChemistryThe University of EdinburghUK
- Centre for Molecular NanometrologyUniversity of StrathclydeUK
| | - Ailsa Geddis
- Centre for Inflammation ResearchThe University ofEdinburghUK
- EaStCHEM School of ChemistryThe University of EdinburghUK
| | - Anke Reinders
- Department of Plant and Microbial BiologyUniversity of MinnesotaUSA
| | - John M. Ward
- Department of Plant and Microbial BiologyUniversity of MinnesotaUSA
| | - Karl Oparka
- Institute of Molecular Plant SciencesThe University of EdinburghUK
| | - Marc Vendrell
- Centre for Inflammation ResearchThe University ofEdinburghUK
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21
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de Moliner F, Knox K, Gordon D, Lee M, Tipping WJ, Geddis A, Reinders A, Ward JM, Oparka K, Vendrell M. A Palette of Minimally Tagged Sucrose Analogues for Real-Time Raman Imaging of Intracellular Plant Metabolism. Angew Chem Int Ed Engl 2021; 60:7637-7642. [PMID: 33491852 PMCID: PMC8048481 DOI: 10.1002/anie.202016802] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Indexed: 12/20/2022]
Abstract
Sucrose is the main saccharide used for long-distance transport in plants and plays an essential role in energy metabolism; however, there are no analogues for real-time imaging in live cells. We have optimised a synthetic approach to prepare sucrose analogues including very small (≈50 Da or less) Raman tags in the fructose moiety. Spectroscopic analysis identified the alkyne-tagged compound 6 as a sucrose analogue recognised by endogenous transporters in live cells and with higher Raman intensity than other sucrose derivatives. Herein, we demonstrate the application of compound 6 as the first optical probe to visualise real-time uptake and intracellular localisation of sucrose in live plant cells using Raman microscopy.
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Affiliation(s)
| | - Kirsten Knox
- Institute of Molecular Plant SciencesThe University of EdinburghUK
| | - Doireann Gordon
- Centre for Inflammation ResearchThe University ofEdinburghUK
| | - Martin Lee
- Cancer Research (UK) Edinburgh CentreThe University of EdinburghUK
| | - William J. Tipping
- EaStCHEM School of ChemistryThe University of EdinburghUK
- Centre for Molecular NanometrologyUniversity of StrathclydeUK
| | - Ailsa Geddis
- Centre for Inflammation ResearchThe University ofEdinburghUK
- EaStCHEM School of ChemistryThe University of EdinburghUK
| | - Anke Reinders
- Department of Plant and Microbial BiologyUniversity of MinnesotaUSA
| | - John M. Ward
- Department of Plant and Microbial BiologyUniversity of MinnesotaUSA
| | - Karl Oparka
- Institute of Molecular Plant SciencesThe University of EdinburghUK
| | - Marc Vendrell
- Centre for Inflammation ResearchThe University ofEdinburghUK
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22
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Lu J, Le Hir R, Gómez-Páez DM, Coen O, Péchoux C, Jasinski S, Magnani E. The nucellus: between cell elimination and sugar transport. PLANT PHYSIOLOGY 2021; 185:478-490. [PMID: 33721907 PMCID: PMC8133628 DOI: 10.1093/plphys/kiaa045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 11/10/2020] [Indexed: 05/29/2023]
Abstract
The architecture of the seed is shaped by the processes of tissue partitioning, which determines the volume ratio of maternal and zygotic tissues, and nutrient partitioning, which regulates nutrient distribution among tissues. In angiosperms, early seed development is characterized by antagonistic development of the nucellus maternal tissue and the endosperm fertilization product to become the main sugar sink. This process marked the evolution of angiosperms and outlines the most ancient seed architectures. In Arabidopsis, the endosperm partially eliminates the nucellus and imports sugars from the seed coat. Here, we show that the nucellus is symplasmically connected to the chalaza, the seed nutrient unloading zone, and works as both a sugar sink and source alongside the seed coat. After fertilization, the transient nucellus accumulates starch early on and releases it in the apoplasmic space during its elimination. By contrast, the persistent nucellus exports sugars toward the endosperm through the SWEET4 hexose facilitator. Finally, we analyzed sugar metabolism and transport in the transparent testa 16 mutant, which fails to undergo nucellus cell elimination, which shed light on the coordination between tissue and nutrient partitioning. Overall, this study identifies a path of sugar transport in the Arabidopsis seed and describes a link between sugar redistribution and the nucellus cell-elimination program.
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Affiliation(s)
- Jing Lu
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
- École Doctorale 567 Sciences du Végétal, University Paris-Sud, University of Paris-Saclay, bat 360, 91405 Orsay Cedex, France
| | - Rozenn Le Hir
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
| | - Dennys-Marcela Gómez-Páez
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
| | - Olivier Coen
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
- École Doctorale 567 Sciences du Végétal, University Paris-Sud, University of Paris-Saclay, bat 360, 91405 Orsay Cedex, France
| | - Christine Péchoux
- INRAE, Génétique Animale et Biologie Intégrative, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France
| | - Sophie Jasinski
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
| | - Enrico Magnani
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026 Versailles Cedex, France
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23
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Robe K, Izquierdo E, Vignols F, Rouached H, Dubos C. The Coumarins: Secondary Metabolites Playing a Primary Role in Plant Nutrition and Health. TRENDS IN PLANT SCIENCE 2021; 26:248-259. [PMID: 33246890 DOI: 10.1016/j.tplants.2020.10.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 05/16/2023]
Abstract
Although abundant in soils, iron (Fe) is poorly bioavailable for plants. Improving Fe uptake in crops, enabling them to grow in Fe-depleted soils, has become a major focal interest. The secretion of Fe-mobilizing coumarins by plant roots recently emerged as an important factor allowing nongrass species to cope with low Fe bioavailability. The main molecular actors involved in the biosynthesis and secretion of coumarins have been identified, but the precise regulatory mechanisms that tune their production remain poorly understood. Here, we review the recent progress in coumarin synthesis and transport in plants and future research directions to gain knowledge of these mechanisms, which will offer novel opportunities for improving plant growth and health and for generating Fe-fortified crops.
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Affiliation(s)
- Kevin Robe
- BPMP, Université de Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France
| | - Esther Izquierdo
- BPMP, Université de Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France
| | - Florence Vignols
- BPMP, Université de Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France
| | - Hatem Rouached
- BPMP, Université de Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France; Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA; Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
| | - Christian Dubos
- BPMP, Université de Montpellier, CNRS, INRAE, Montpellier SupAgro, Montpellier, France.
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24
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Peters WS, Jensen KH, Stone HA, Knoblauch M. Plasmodesmata and the problems with size: Interpreting the confusion. JOURNAL OF PLANT PHYSIOLOGY 2021; 257:153341. [PMID: 33388666 DOI: 10.1016/j.jplph.2020.153341] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 05/14/2023]
Abstract
Plant tissues exhibit a symplasmic organization; the individual protoplasts are connected to their neighbors via cytoplasmic bridges that extend through pores in the cell walls. These bridges may have diameters of a micrometer or more, as in the sieve pores of the phloem, but in most cell types they are smaller. Historically, botanists referred to cytoplasmic bridges of all sizes as plasmodesmata. The meaning of the term began to shift when the transmission electron microscope (TEM) became the preferred tool for studying these structures. Today, a plasmodesma is widely understood to be a 'nano-scale' pore. Unfortunately, our understanding of these nanoscopic channels suffers from methodological limitations. This is exemplified by the fact that state-of-the-art EM techniques appear to reveal plasmodesmal pore structures that are much smaller than the tracer molecules known to diffuse through these pores. In general, transport processes in pores that have dimensions in the size range of the transported molecules are governed by different physical parameters than transport process in the macroscopic realm. This can lead to unexpected effects, as experience in nanofluidic technologies demonstrates. Our discussion of problems of size in plasmodesma research leads us to conclude that the field will benefit from technomimetic reasoning - the utilization of concepts developed in applied nanofluidics for the interpretation of biological systems.
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Affiliation(s)
- Winfried S Peters
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA; Department of Biology, Purdue University Fort Wayne, Fort Wayne, IN, 46805, USA.
| | - Kaare H Jensen
- Department of Physics, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA.
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
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25
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Stassen MJJ, Hsu SH, Pieterse CMJ, Stringlis IA. Coumarin Communication Along the Microbiome-Root-Shoot Axis. TRENDS IN PLANT SCIENCE 2021; 26:169-183. [PMID: 33023832 DOI: 10.1016/j.tplants.2020.09.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 05/06/2023]
Abstract
Plants shape their rhizosphere microbiome by secreting root exudates into the soil environment. Recently, root-exuded coumarins were identified as novel players in plant-microbiome communication. Beneficial members of the root-associated microbiome stimulate coumarin biosynthesis in roots and their excretion into the rhizosphere. The iron-mobilizing activity of coumarins facilitates iron uptake from the soil environment, while their selective antimicrobial activity shapes the root microbiome, resulting in promotion of plant growth and health. Evidence is accumulating that, in analogy to strigolactones and flavonoids, coumarins may act in microbiome-to-root-to-shoot signaling events. Here, we review this multifaceted role of coumarins in bidirectional chemical communication along the microbiome-root-shoot axis.
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Affiliation(s)
- Max J J Stassen
- Plant-Microbe Interactions, Department of Biology, Science for Life, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Shu-Hua Hsu
- Plant-Microbe Interactions, Department of Biology, Science for Life, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands; Department of Agronomy, National Taiwan University, No. 1, Section 4, Roosevelt Road, 10617, Taipei, Taiwan
| | - Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Science for Life, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Ioannis A Stringlis
- Plant-Microbe Interactions, Department of Biology, Science for Life, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands.
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26
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Abstract
Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at most physiological pHs, strongly relies on families of active transporters. These proteins import auxin from the extracellular space or export it into the same. Mutations in these components have profound impacts on biological processes. Another transport route available to auxin, once the substance is inside the cell, are plasmodesmata connections. These small channels connect the cytoplasms of neighbouring plant cells and enable flow between them. Interestingly, the biological significance of this latter mode of transport is only recently starting to emerge with examples from roots, hypocotyls and leaves. The existence of two transport systems provides opportunities for reciprocal cross-regulation. Indeed, auxin levels influence proteins controlling plasmodesmata permeability, while cell-cell communication affects auxin biosynthesis and transport. In an evolutionary context, transporter driven cell-cell auxin movement and plasmodesmata seem to have evolved around the same time in the green lineage. This highlights a co-existence from early on and a likely functional specificity of the systems. Exploring more situations where auxin movement via plasmodesmata has relevance for plant growth and development, and clarifying the regulation of such transport, will be key aspects in coming years.This article has an associated Future Leader to Watch interview with the author of the paper.
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Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge CB2 1 LR, UK
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27
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Rodrigues CM, Müdsam C, Keller I, Zierer W, Czarnecki O, Corral JM, Reinhardt F, Nieberl P, Fiedler-Wiechers K, Sommer F, Schroda M, Mühlhaus T, Harms K, Flügge UI, Sonnewald U, Koch W, Ludewig F, Neuhaus HE, Pommerrenig B. Vernalization Alters Sink and Source Identities and Reverses Phloem Translocation from Taproots to Shoots in Sugar Beet. THE PLANT CELL 2020; 32:3206-3223. [PMID: 32769131 PMCID: PMC7534467 DOI: 10.1105/tpc.20.00072] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/23/2020] [Accepted: 07/30/2020] [Indexed: 05/20/2023]
Abstract
During their first year of growth, overwintering biennial plants transport Suc through the phloem from photosynthetic source tissues to storage tissues. In their second year, they mobilize carbon from these storage tissues to fuel new growth and reproduction. However, both the mechanisms driving this shift and the link to reproductive growth remain unclear. During vegetative growth, biennial sugar beet (Beta vulgaris) maintains a steep Suc concentration gradient between the shoot (source) and the taproot (sink). To shift from vegetative to generative growth, they require a chilling phase known as vernalization. We studied sugar beet sink-source dynamics upon vernalization and showed that before flowering, the taproot underwent a reversal from a sink to a source of carbohydrates. This transition was induced by transcriptomic and functional reprogramming of sugar beet tissue, resulting in a reversal of flux direction in the phloem. In this transition, the vacuolar Suc importers and exporters TONOPLAST SUGAR TRANSPORTER2;1 and SUCROSE TRANSPORTER4 were oppositely regulated, leading to the mobilization of sugars from taproot storage vacuoles. Concomitant changes in the expression of floral regulator genes suggest that these processes are a prerequisite for bolting. Our data will help both to dissect the metabolic and developmental triggers for bolting and to identify potential targets for genome editing and breeding.
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Affiliation(s)
| | - Christina Müdsam
- Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Isabel Keller
- Plant Physiology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Wolfgang Zierer
- Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Olaf Czarnecki
- Kleinwanzlebener Saatzucht SE & Co. KGaA, 37574 Einbeck, Germany
| | - José María Corral
- Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Frank Reinhardt
- Plant Physiology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Petra Nieberl
- Molecular Plant Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | | | - Frederik Sommer
- Biotechnology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Michael Schroda
- Biotechnology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Timo Mühlhaus
- Bioinformatics, University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Karsten Harms
- Südzucker AG, Central Department for Research, Development, and Service, 67283 Obrigheim/Pfalz, Germany
| | - Ulf-Ingo Flügge
- Botanical Institute, Cologne Biocenter and Center of Excellence on Plant Science, 50674 Cologne, Germany
| | - Uwe Sonnewald
- Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Wolfgang Koch
- Kleinwanzlebener Saatzucht SE & Co. KGaA, 37574 Einbeck, Germany
| | - Frank Ludewig
- Kleinwanzlebener Saatzucht SE & Co. KGaA, 37574 Einbeck, Germany
| | - H Ekkehard Neuhaus
- Plant Physiology, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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28
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Intercellular trafficking via plasmodesmata: molecular layers of complexity. Cell Mol Life Sci 2020; 78:799-816. [PMID: 32920696 PMCID: PMC7897608 DOI: 10.1007/s00018-020-03622-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/28/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022]
Abstract
Plasmodesmata are intercellular pores connecting together most plant cells. These structures consist of a central constricted form of the endoplasmic reticulum, encircled by some cytoplasmic space, in turn delimited by the plasma membrane, itself ultimately surrounded by the cell wall. The presence and structure of plasmodesmata create multiple routes for intercellular trafficking of a large spectrum of molecules (encompassing RNAs, proteins, hormones and metabolites) and also enable local signalling events. Movement across plasmodesmata is finely controlled in order to balance processes requiring communication with those necessitating symplastic isolation. Here, we describe the identities and roles of the molecular components (specific sets of lipids, proteins and wall polysaccharides) that shape and define plasmodesmata structural and functional domains. We highlight the extensive and dynamic interactions that exist between the plasma/endoplasmic reticulum membranes, cytoplasm and cell wall domains, binding them together to effectively define plasmodesmata shapes and purposes.
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29
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Ren Y, Sun H, Zong M, Guo S, Ren Z, Zhao J, Li M, Zhang J, Tian S, Wang J, Yu Y, Gong G, Zhang H, He H, Li L, Zhang X, Liu F, Fei Z, Xu Y. Localization shift of a sugar transporter contributes to phloem unloading in sweet watermelons. THE NEW PHYTOLOGIST 2020; 227:1858-1871. [PMID: 32453446 DOI: 10.1111/nph.16659] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/26/2020] [Indexed: 05/15/2023]
Abstract
Unloading sugar from sink phloem by transporters is complex and much remains to be understood about this phenomenon in the watermelon fruit. Here, we report a novel vacuolar sugar transporter (ClVST1) identified through map-based cloning and association study, whose expression in fruit phloem is associated with accumulation of sucrose (Suc) in watermelon fruit. ClVST197 knockout lines show decreased sugar content and total biomass, whereas overexpression of ClVST197 increases Suc content. Population genomic and subcellular localization analyses strongly suggest a single-base change at the coding region of ClVST197 as a major molecular event during watermelon domestication, which results in the truncation of 45 amino acids and shifts the localization of ClVST197 to plasma membranes in sweet watermelons. Molecular, biochemical and phenotypic analyses indicate that ClVST197 is a novel sugar transporter for Suc and glucose efflux and unloading. Functional characterization of ClVST1 provides a novel strategy to increase sugar sink potency during watermelon domestication.
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Affiliation(s)
- Yi Ren
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Honghe Sun
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Mei Zong
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Shaogui Guo
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Zhijie Ren
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Jianyu Zhao
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, MOE Joint International Research Laboratory of Crop Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Maoying Li
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Jie Zhang
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Shouwei Tian
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Jinfang Wang
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Yongtao Yu
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Guoyi Gong
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Haiying Zhang
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Hongju He
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Legong Li
- College of Life Sciences, Capital Normal University, Beijing, 100048, China
| | - Xiaolan Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, MOE Joint International Research Laboratory of Crop Molecular Breeding, China Agricultural University, Beijing, 100193, China
| | - Fan Liu
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
| | - Zhangjun Fei
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA
- US Department of Agriculture-Agricultural Research Service, Robert W. Holley Center for Agriculture and Health, Ithaca, NY, 14853, USA
| | - Yong Xu
- National Watermelon and Melon Improvement Center, Beijing Academy of Agricultural and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, 100097, China
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30
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Pommerrenig B, Müdsam C, Kischka D, Neuhaus HE. Treat and trick: common regulation and manipulation of sugar transporters during sink establishment by the plant and the pathogen. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3930-3940. [PMID: 32242225 DOI: 10.1093/jxb/eraa168] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
Sugar transport proteins are crucial for the coordinated allocation of sugars. In this Expert View we summarize recent key findings of the roles and regulation of sugar transporters in inter- and intracellular transport by focusing on applied approaches, demonstrating how sucrose transporter activity may alter source and sink dynamics and their identities. The plant itself alters its sugar transport activity in a developmentally dependent manner to either establish or load endogenous sinks, for example, during tuber formation and filling. Pathogens represent aberrant sinks that trigger the plant to induce the same processes, resulting in loss of carbon assimilates. We explore common mechanisms of intrinsic, developmentally dependent processes and aberrant, pathogen-induced manipulation of sugar transport. Transporter activity may also be targeted by breeding or genetic modification approaches in crop plants to alter source and sink metabolism upon the overexpression or heterologous expression of these proteins. In addition, we highlight recent progress in the use of sugar analogs to study these processes in vivo.
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Affiliation(s)
| | - Christina Müdsam
- Biochemistry, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Dominik Kischka
- Biochemistry, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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31
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Mendive‐Tapia L, Wang J, Vendrell M. Fluorescent cyclic peptides for cell imaging. Pept Sci (Hoboken) 2020. [DOI: 10.1002/pep2.24181] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
| | - Jinling Wang
- Centre for Inflammation Research The University of Edinburgh Edinburgh UK
| | - Marc Vendrell
- Centre for Inflammation Research The University of Edinburgh Edinburgh UK
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32
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Mehdi R, Lamm CE, Bodampalli Anjanappa R, Müdsam C, Saeed M, Klima J, Kraner ME, Ludewig F, Knoblauch M, Gruissem W, Sonnewald U, Zierer W. Symplasmic phloem unloading and radial post-phloem transport via vascular rays in tuberous roots of Manihot esculenta. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5559-5573. [PMID: 31232453 PMCID: PMC6812707 DOI: 10.1093/jxb/erz297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/15/2019] [Indexed: 05/04/2023]
Abstract
Cassava (Manihot esculenta) is one of the most important staple food crops worldwide. Its starchy tuberous roots supply over 800 million people with carbohydrates. Yet, surprisingly little is known about the processes involved in filling of those vital storage organs. A better understanding of cassava carbohydrate allocation and starch storage is key to improving storage root yield. Here, we studied cassava morphology and phloem sap flow from source to sink using transgenic pAtSUC2::GFP plants, the phloem tracers esculin and 5(6)-carboxyfluorescein diacetate, as well as several staining techniques. We show that cassava performs apoplasmic phloem loading in source leaves and symplasmic unloading into phloem parenchyma cells of tuberous roots. We demonstrate that vascular rays play an important role in radial transport from the phloem to xylem parenchyma cells in tuberous roots. Furthermore, enzymatic and proteomic measurements of storage root tissues confirmed high abundance and activity of enzymes involved in the sucrose synthase-mediated pathway and indicated that starch is stored most efficiently in the outer xylem layers of tuberous roots. Our findings form the basis for biotechnological approaches aimed at improved phloem loading and enhanced carbohydrate allocation and storage in order to increase tuberous root yield of cassava.
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Affiliation(s)
- Rabih Mehdi
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Christian E Lamm
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | | | - Christina Müdsam
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Muhammad Saeed
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Janine Klima
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Max E Kraner
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Frank Ludewig
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Wilhelm Gruissem
- Plant Biotechnology, Department of Biology, ETH Zurich, Zurich, Switzerland
- Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung City, Taiwan
| | - Uwe Sonnewald
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Wolfgang Zierer
- Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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33
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Pommerrenig B, Eggert K, Bienert GP. Boron Deficiency Effects on Sugar, Ionome, and Phytohormone Profiles of Vascular and Non-Vascular Leaf Tissues of Common Plantain ( Plantago major L.). Int J Mol Sci 2019; 20:E3882. [PMID: 31395813 PMCID: PMC6719229 DOI: 10.3390/ijms20163882] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 12/15/2022] Open
Abstract
Vascular tissues essentially regulate water, nutrient, photo-assimilate, and phytohormone logistics throughout the plant body. Boron (B) is crucial for the development of the vascular tissue in many dicotyledonous plant taxa and B deficiency particularly affects the integrity of phloem and xylem vessels, and, therefore, functionality of long-distance transport. We hypothesize that changes in the plants' B nutritional status evoke differential responses of the vasculature and the mesophyll. However, direct analyses of the vasculature in response to B deficiency are lacking, due to the experimental inaccessibility of this tissue. Here, we generated biochemical and physiological understanding of B deficiency response reactions in common plantain (Plantago major L.), from which pure and intact vascular bundles can be extracted. Low soil B concentrations affected quantitative distribution patterns of various phytohormones, sugars and macro-, and micronutrients in a tissue-specific manner. Vascular sucrose levels dropped, and sucrose loading into the phloem was reduced under low B supply. Phytohormones responded selectively to B deprivation. While concentrations of abscisic acid and salicylic acid decreased at low B supply, cytokinins and brassinosteroids increased in the vasculature and the mesophyll, respectively. Our results highlight the biological necessity to analyze nutrient deficiency responses in a tissue- rather organ-specific manner.
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Affiliation(s)
- Benjamin Pommerrenig
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, D-06466 Gatersleben, Germany
- Plant Physiology, University of Kaiserslautern, Paul-Ehrlich-Str. 22, D-67653 Kaiserslautern, Germany
| | - Kai Eggert
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, D-06466 Gatersleben, Germany
| | - Gerd P Bienert
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, D-06466 Gatersleben, Germany.
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34
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Cheng Z, Valença WO, Dias GG, Scott J, Barth ND, de Moliner F, Souza GBP, Mellanby RJ, Vendrell M, da Silva Júnior EN. Natural product-inspired profluorophores for imaging NQO1 activity in tumour tissues. Bioorg Med Chem 2019; 27:3938-3946. [PMID: 31327676 DOI: 10.1016/j.bmc.2019.07.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 11/30/2022]
Abstract
Herein we designed a collection of trimethyl-lock quinone profluorophores as activity-based probes for imaging NAD(P)H:quinone oxidoreductase (NQO1) in cancer cells and tumour tissues. Profluorophores were prepared via synthetic routes from naturally-occurring quinones and characterised in vitro using recombinant enzymes, to be further validated in cells and fresh frozen canine tumour tissues as potential new tools for cancer detection and imaging.
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Affiliation(s)
- Zhiming Cheng
- Centre for Inflammation Research, The University of Edinburgh, EH16 4TJ Edinburgh, UK
| | - Wagner O Valença
- Institute of Exact Sciences, Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
| | - Gleiston G Dias
- Institute of Exact Sciences, Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
| | - Jamie Scott
- Centre for Inflammation Research, The University of Edinburgh, EH16 4TJ Edinburgh, UK
| | - Nicole D Barth
- Centre for Inflammation Research, The University of Edinburgh, EH16 4TJ Edinburgh, UK
| | - Fabio de Moliner
- Centre for Inflammation Research, The University of Edinburgh, EH16 4TJ Edinburgh, UK
| | - Gabriela B P Souza
- Institute of Exact Sciences, Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil
| | - Richard J Mellanby
- Royal (Dick) School of Veterinary Studies, The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, EH25 9RG Roslin, UK
| | - Marc Vendrell
- Centre for Inflammation Research, The University of Edinburgh, EH16 4TJ Edinburgh, UK.
| | - Eufrânio N da Silva Júnior
- Institute of Exact Sciences, Department of Chemistry, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
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35
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Sevanto S. Methods for Assessing the Role of Phloem Transport in Plant Stress Responses. Methods Mol Biol 2019; 2014:311-336. [PMID: 31197806 DOI: 10.1007/978-1-4939-9562-2_25] [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] [Indexed: 02/16/2023]
Abstract
Delivery of carbohydrates to tissues that need them under stress is important for plant defenses and survival. Yet, little is known on how phloem function is altered under stress, and how that influences plant responses to stress. This is because phloem is a challenging tissue to study. It consists of cells of various types with soft cell walls, and the cells show strong wounding reactions to protect their integrity, making both imaging and functional studies challenging. This chapter summarizes theories on how phloem transport is affected by stress and presents methods that have been used to gain the current knowledge. These techniques range from tracer studies and imaging to carbon balance and anatomical analyses. Advances in these techniques in the recent years have considerably increased our ability to investigate phloem function, and application of the new methods on plant stress studies will help provide a more comprehensive picture of phloem function and its limitations under stress.
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Affiliation(s)
- Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
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36
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Measuring Phloem Transport Velocity on a Tissue Level Using a Phloem-Mobile Dye. Methods Mol Biol 2019. [PMID: 31197798 DOI: 10.1007/978-1-4939-9562-2_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Here we describe an in vivo dye-tracking method for measuring phloem transport velocity in seedlings, leaves and petioles and potentially other translucent plant tissues. The method requires measurement of the fluorescent signal of a phloem-mobile fluorescent dye using sensitive photo-sensors placed external to the plant. Following dye application, velocity is determined using laser fluorescence bleaching and measuring the time it takes for the bleach front to reach a light sensor. This method can be used to measure phloem transport velocity on intact plants with minimal disturbance and has a potential to be used under a variety of growth conditions and in the field. Because there are large differences among species in their anatomy, this method should be optimized to individual plants and tissue types.
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37
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Machin FQ, Beckers M, Tian X, Fairnie A, Cheng T, Scheible WR, Doerner P. Inducible reporter/driver lines for the Arabidopsis root with intrinsic reporting of activity state. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:153-164. [PMID: 30548978 DOI: 10.1111/tpj.14192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 06/09/2023]
Abstract
Cell-, tissue- or organ-specific inducible expression systems are powerful tools for functional analysis of changes to the pattern, level or timing of gene expression. However, plant researchers lack standardised reagents that promote reproducibility across the community. Here, we report the development and functional testing of a Gateway-based system for quantitatively, spatially and temporally controlling inducible gene expression in Arabidopsis that overcomes several drawbacks of the legacy systems. We used this modular driver/effector system with intrinsic reporting of spatio-temporal promoter activity to generate 18 well-characterised homozygous transformed lines showing the expected expression patterns specific for the major cell types of the Arabidopsis root; seed and plasmid vectors are available through the Arabidopsis stock centre. The system's tight regulation was validated by assessing the effects of diphtheria toxin A chain expression. We assessed the utility of Production of Anthocyanin Pigment 1 (PAP1) as an encoded effector mediating cell-autonomous marks. With this shared resource of characterised reference driver lines, which can be expanded with additional promoters and the use of other fluorescent proteins, we aim to contribute towards enhancing reproducibility of qualitative and quantitative analyses.
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Affiliation(s)
- Frank Qasim Machin
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Malin Beckers
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Xin Tian
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Alice Fairnie
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | - Teri Cheng
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
| | | | - Peter Doerner
- Institute for Molecular Plant Science, University of Edinburgh, Edinburgh, UK
- Max-Planck Institute of Molecular Plant Physiology, Science Park, Golm, Germany
- Laboratoire de Physiologie Cellulaire & Végétale, University Grenoble Alpes, CNRS, CEA, INRA, BIG-LPCV, 38000, Grenoble, France
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38
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Hu Y, Tian S, Foyer CH, Hou D, Wang H, Zhou W, Liu T, Ge J, Lu L, Lin X. Efficient phloem transport significantly remobilizes cadmium from old to young organs in a hyperaccumulator Sedum alfredii. JOURNAL OF HAZARDOUS MATERIALS 2019; 365:421-429. [PMID: 30453235 DOI: 10.1016/j.jhazmat.2018.11.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/08/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
Our knowledge of cadmium (Cd) in hyperaccumulators mainly concerns root uptake, xylem translocation and foliar detoxification, while little attention has been paid to the role of phloem remobilization. We investigated Cd distribution in different organs of the hyperaccumulating ecotype (HE) of Sedum alfredii and compared its Cd phloem transport with that of the non-hyperaccumulating ecotype (NHE). In HE, results of micro X-ray fluorescence revealed that Cd preferentially accumulated in younger organs compared to the older, and its primary distribution sites changed from parenchyma to vascular/epidermal cells with increased organ age. Strong Cd signals in phloem cells were observed in HE old stems. Pre-stored Cd was readily exported from older to growing leaves, which could be accelerated by leaf senescence. Short-term feeding experiments showed that phloem-mediated Cd transport is rapid and efficient in HE. HE relocated 44% of the total leaf-labelled Cd to other organs, while over 90% Cd was retained in labelled leaves of NHE. High Cd was detected in HE phloem exudates but not in those from NHE leaves. In conclusion, Cd phloem transport is efficient and important for dominating the age-dependent Cd allocation in plants of HE S. alfredii.
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Affiliation(s)
- Yan Hu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK
| | - Shengke Tian
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Christine H Foyer
- Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, West Yorkshire, LS2 9JT, UK
| | - Dandi Hou
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Haixin Wang
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Weiwei Zhou
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Ting Liu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Jun Ge
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
| | - Lingli Lu
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China.
| | - Xianyong Lin
- Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China
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39
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Losada JM, Holbrook NM. Scaling of phloem hydraulic resistance in stems and leaves of the understory angiosperm shrub Illicium parviflorum. AMERICAN JOURNAL OF BOTANY 2019; 106:244-259. [PMID: 30793276 DOI: 10.1002/ajb2.1241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY Recent studies in canopy-dominant trees revealed axial scaling of phloem structure. However, whether this pattern is found in woody plants of the understory, the environment of most angiosperms from the ANA grade (Amborellales-Nymphaeales-Austrobaileyales), is unknown. METHODS We used seedlings and adult plants of the understory tropical shrub Illicium parviflorum, a member of the lineage Austrobaileyales, to explore the anatomy and physiology of the phloem in their aerial parts, including changes through ontogeny. KEY RESULTS Adult plants maintain a similar proportion of phloem tissue across stem diameters, but larger conduit dimensions and number cause the hydraulic resistance of the phloem to decrease toward the base of the plant. Small sieve plate pores resulted in an overall higher sieve tube hydraulic resistance than has been reported in other woody angiosperms. Sieve elements increase in size from minor to major leaf veins, but were shorter and narrower in petioles. The low carbon assimilation rates of seedlings and mature plants contrasted with a 3-fold higher phloem sap velocity in seedlings, suggesting that phloem transport velocity is modulated through ontogeny. CONCLUSIONS The overall architecture of the phloem tissue in this understory angiosperm shrub scales in a manner consistent with taller trees that make up the forest canopy. Thus, the evolution of larger sieve plate pores in canopy-dominant trees may have played a key role in allowing woody angiosperms to extend beyond their understory origins.
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Affiliation(s)
- Juan M Losada
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
- Arnold Arboretum of Harvard University, 1300 Centre St., Boston, MA, 02130, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
- Arnold Arboretum of Harvard University, 1300 Centre St., Boston, MA, 02130, USA
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40
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Knox K. Measuring Phloem Transport Velocity in Arabidopsis Seedlings Using the Fluorescent Coumarin Glucoside, Esculin. Methods Mol Biol 2019; 2014:195-201. [PMID: 31197797 DOI: 10.1007/978-1-4939-9562-2_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Historically, the ability to measure the velocity of phloem sap in small seedlings and plants has been technically challenging. The phloem tissues are delicate, often flow is blocked entirely if perturbed. Furthermore, the depth that phloem sieve tubes are located within the plant has hindered many techniques. Previously published methods have lacked the spatial and temporal resolution required for measurements in small seedlings, are usually laborious or are not suited to in vivo studies. Here we describe a rapid, high-throughput method using the fluorescent coumarin glucoside esculin as a probe to measure the phloem transport velocity in the roots of young Arabidopsis seedlings.
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Affiliation(s)
- Kirsten Knox
- Institute of Molecular Plant Science, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
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41
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Cayla T, Le Hir R, Dinant S. Live-Cell Imaging of Fluorescently Tagged Phloem Proteins with Confocal Microscopy. Methods Mol Biol 2019; 2014:95-108. [PMID: 31197789 DOI: 10.1007/978-1-4939-9562-2_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Confocal laser scanning microscopy can enable observation of phloem cells in living tissues. Here we describe live imaging of phloem cells in the leaves and roots of Arabidopsis thaliana using fluorescently tagged proteins, either expressed in the vasculature using phloem specific promoters or constitutively expressed reference marker lines. Now, the majority of phloem cell types can be identified, allowing a precise cellular and subcellular localization of phloem proteins.
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Affiliation(s)
- Thibaud Cayla
- UMR 1318, Institut Jean-Pierre Bourgin, INRA-AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, France
| | - Rozenn Le Hir
- UMR 1318, Institut Jean-Pierre Bourgin, INRA-AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, France
| | - Sylvie Dinant
- UMR 1318, Institut Jean-Pierre Bourgin, INRA-AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, France.
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42
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Zhao C, Mendive-Tapia L, Vendrell M. Fluorescent peptides for imaging of fungal cells. Arch Biochem Biophys 2018; 661:187-195. [PMID: 30465736 DOI: 10.1016/j.abb.2018.11.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/06/2018] [Accepted: 11/16/2018] [Indexed: 12/17/2022]
Abstract
Fungal infections, especially with the advent of antimicrobial resistance, represent a major burden to our society. As a result, there has been an increasing interest in the development of new probes that accelerate the study of fungi-related biological processes and facilitate novel clinical diagnostic and treatment strategies. Fluorescence-based reporters can provide dynamic information at the molecular level with high spatial resolution. However, conventional fluorescent probes for microbes often suffer from low specificity. In the last decade, numerous studies have been reported on the chemical design and application of fluorescent peptides for both in vitro and in vivo imaging of fungal cells. In this article, we review different strategies used in the preparation of fluorescent peptides for pathogenic fungi as well as some of their applications in medical imaging and in mode-of-action mechanistic studies.
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Affiliation(s)
- Can Zhao
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, M13 9NT, United Kingdom
| | - Lorena Mendive-Tapia
- Centre for Inflammation Research, The University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom
| | - Marc Vendrell
- Centre for Inflammation Research, The University of Edinburgh, Edinburgh, EH16 4TJ, United Kingdom.
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43
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Knox K, Paterlini A, Thomson S, Oparka K. The Coumarin Glucoside, Esculin, Reveals Rapid Changes in Phloem-Transport Velocity in Response to Environmental Cues. PLANT PHYSIOLOGY 2018; 178:795-807. [PMID: 30111635 PMCID: PMC6181028 DOI: 10.1104/pp.18.00574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/03/2018] [Indexed: 05/24/2023]
Abstract
The study of phloem transport and its vital roles in long-distance communication and carbon allocation have been hampered by a lack of suitable tools that allow high-throughput, real-time studies. Esculin, a fluorescent coumarin glucoside, is recognized by Suc transporters, including AtSUC2, which loads it into the phloem for translocation to sink tissues. These properties make it an ideal tool for use in live-imaging experiments, where it acts as a surrogate for Suc. Here, we show that esculin is translocated with a similar efficiency to Suc and, because of its ease of application and detection, demonstrate that it is an ideal tool for in vivo studies of phloem transport. We used esculin to determine the effect of different environmental cues on the velocity of phloem transport. We provide evidence that fluctuations in cotyledon Suc levels influence phloem velocity rapidly, supporting the pressure-flow model of phloem transport. Under acute changes in light levels, the phloem velocity mirrored changes in the expression of AtSUC2 This observation suggests that under certain environmental conditions, transcriptional regulation may affect the abundance of AtSUC2 and thus regulate the phloem transport velocity.
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Affiliation(s)
- Kirsten Knox
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Andrea Paterlini
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Simon Thomson
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Karl Oparka
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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44
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Wang J, Song J, Clark G, Roux SJ. ANN1 and ANN2 Function in Post-Phloem Sugar Transport in Root Tips to Affect Primary Root Growth. PLANT PHYSIOLOGY 2018; 178:390-401. [PMID: 30018170 PMCID: PMC6130020 DOI: 10.1104/pp.18.00713] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 07/04/2018] [Indexed: 05/08/2023]
Abstract
Annexins are a multigene family of calcium-dependent membrane-binding proteins that play important roles in plant cell signaling. Annexins are multifunctional proteins, and their function in plants is not comprehensively understood. Arabidopsis (Arabidopsis thaliana) annexins ANN1 and ANN2 are 64% identical in their primary structure, and both are highly expressed in seedlings. Here, we showed that ann-mutant seedlings grown in the absence of sugar show decreased primary root growth and altered columella cells in root caps; however, these mutant defects are rescued by Suc, Glc, or Fru. In seedlings grown without sugar, significant up-regulation of photosynthetic gene expression and chlorophyll accumulation was found in ann-mutant cotyledons compared to that in wild type, which indicates potential sugar starvation in the roots of ann-mutant seedlings. Unexpectedly, the overall sugar content of ann-mutant primary roots was significantly higher than that of wild-type roots when grown without sugar. To examine the diffusion of sugar along the entire root to the root tip, we examined the unloading pattern of carboxyfluorescein dye and found that post-phloem sugar transport was impaired in ann-mutant root tips compared to that in wild type. Increased levels of ROS and callose were detected in the root tips of ann-mutant seedlings grown without Suc, the latter of which would restrict plasmodesmal sugar transport to root tips. Our results indicate that ANN1 and ANN2 play an important role in post-phloem sugar transport to the root tip, which in turn indirectly influences photosynthetic rates in cotyledons. This study expands our understanding of the function of annexins in plants.
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Affiliation(s)
- Jing Wang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
| | - Jawon Song
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, Texas 78712
| | - Greg Clark
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
| | - Stanley J Roux
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712
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45
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McCormick S. A non-invasive and versatile way to assess plasmodesmatal connections. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:749-750. [PMID: 29878550 DOI: 10.1111/tpj.13946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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46
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Knox K, Oparka K. Illuminating the translocation stream. CURRENT OPINION IN PLANT BIOLOGY 2018; 43:113-118. [PMID: 29729487 DOI: 10.1016/j.pbi.2018.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
This review focuses on the recent development of a suite of fluorescent probes that can be used to trace phloem-transport rates in a range of diverse species. Some of these probes are loaded into the phloem by virtue of optimal physico-chemical properties for ion trapping in the high pH environment of the sieve element. However, others are clearly loaded by carrier-mediated transport, such as the blue-emitting probe, esculin, which is loaded into the Arabidopsis phloem by the sucrose transporter, AtSUC2, allowing it to be used as a surrogate for sucrose in phloem transport studies. We also describe additional chemical groups which, although highly charged (e.g. sulphonates), facilitate entry into the phloem. The addition of such 'mobilophores' to existing chemical groups has allowed us to expand the range of fluorophores that can be loaded into the phloem, and provides clues as to the nature of selectivity for phloem loading of xenobiotic compounds.
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Affiliation(s)
- Kirsten Knox
- Institute of Molecular Plant Sciences, Rutherford Building, School of Biological Sciences, Edinburgh University, Max Born Crescent, Kings Buildings, Edinburgh, UK.
| | - Karl Oparka
- Institute of Molecular Plant Sciences, Rutherford Building, School of Biological Sciences, Edinburgh University, Max Born Crescent, Kings Buildings, Edinburgh, UK
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47
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De Moliner F, Knox K, Reinders A, Ward JM, McLaughlin PJ, Oparka K, Vendrell M. Probing binding specificity of the sucrose transporter AtSUC2 with fluorescent coumarin glucosides. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2473-2482. [PMID: 29506213 PMCID: PMC5920547 DOI: 10.1093/jxb/ery075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 02/19/2018] [Indexed: 05/18/2023]
Abstract
The phloem sucrose transporter, AtSUC2, is promiscuous with respect to substrate recognition, transporting a range of glucosides in addition to sucrose, including naturally occurring coumarin glucosides. We used the inherent fluorescence of coumarin glucosides to probe the specificity of AtSUC2 for its substrates, and determined the structure-activity relationships that confer phloem transport in vivo using Arabidopsis seedlings. In addition to natural coumarin glucosides, we synthesized new compounds to identify key structural features that specify recognition by AtSUC2. Our analysis of the structure-activity relationship revealed that the presence of a free hydroxyl group on the coumarin moiety is essential for binding by AtSUC2 and subsequent phloem mobility. Structural modeling of the AtSUC2 substrate-binding pocket explains some important structural requirements for the interaction of coumarin glucosides with the AtSUC2 transporter.
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Affiliation(s)
- Fabio De Moliner
- MRC/UoE Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, UK
| | - Kirsten Knox
- Institute of Molecular Plant Sciences, Max Born Crescent, University of Edinburgh, UK
| | - Anke Reinders
- Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - John M Ward
- Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Paul J McLaughlin
- Institute of Quantitative Biology, Biochemistry and Biotechnology, Max Born Crescent, University of Edinburgh, UK
| | - Karl Oparka
- Institute of Molecular Plant Sciences, Max Born Crescent, University of Edinburgh, UK
- Correspondence: or
| | - Marc Vendrell
- MRC/UoE Centre for Inflammation Research, Queen’s Medical Research Institute, University of Edinburgh, UK
- Correspondence: or
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48
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Rottmann TM, Fritz C, Lauter A, Schneider S, Fischer C, Danzberger N, Dietrich P, Sauer N, Stadler R. Protoplast-Esculin Assay as a New Method to Assay Plant Sucrose Transporters: Characterization of AtSUC6 and AtSUC7 Sucrose Uptake Activity in Arabidopsis Col-0 Ecotype. FRONTIERS IN PLANT SCIENCE 2018; 9:430. [PMID: 29740457 PMCID: PMC5925572 DOI: 10.3389/fpls.2018.00430] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/20/2018] [Indexed: 05/20/2023]
Abstract
The best characterized function of sucrose transporters of the SUC family in plants is the uptake of sucrose into the phloem for long-distance transport of photoassimilates. This important step is usually performed by one specific SUC in every species. However, plants possess small families of several different SUCs which are less well understood. Here, we report on the characterization of AtSUC6 and AtSUC7, two members of the SUC family in Arabidopsis thaliana. Heterologous expression in yeast (Saccharomyces cerevisiae) revealed that AtSUC6Col-0 is a high-affinity H+-symporter that mediates the uptake of sucrose and maltose across the plasma membrane at exceptionally low pH values. Reporter gene analyses revealed a strong expression of AtSUC6Col-0 in reproductive tissues, where the protein product might contribute to sugar uptake into pollen tubes and synergid cells. A knockout of AtSUC6 did not interfere with vegetative development or reproduction, which points toward physiological redundancy of AtSUC6Col-0 with other sugar transporters. Reporter gene analyses showed that AtSUC7Col-0 is expressed in roots and pollen tubes and that this sink specific expression of AtSUC7Col-0 is regulated by intragenic regions. Transport activity of AtSUC7Col-0 could not be analyzed in baker's yeast or Xenopus oocytes because the protein was not correctly targeted to the plasma membrane in both heterologous expression systems. Therefore, a novel approach to analyze sucrose transporters in planta was developed. Plasma membrane localized SUCs including AtSUC6Col-0 and also sucrose specific SWEETs were able to mediate transport of the fluorescent sucrose analog esculin in transformed mesophyll protoplasts. In contrast, AtSUC7Col-0 is not able to mediate esculin transport across the plasma membrane which implicates that AtSUC7Col-0 might be a non-functional pseudogene. The novel protoplast assay provides a useful tool for the quick and quantitative analysis of sucrose transporters in an in planta expression system.
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49
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Mao GL, Yan Y, Chen Y, Wang BF, Xu FF, Zhang ZX, Lin F, Xu HH. Family of Ricinus communis Monosaccharide Transporters and RcSTP1 in Promoting the Uptake of a Glucose-Fipronil Conjugate. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:6169-6178. [PMID: 28692262 DOI: 10.1021/acs.jafc.7b02044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Enhancing the systemic distribution of a bioactive compound by exploiting the vascular transport system of a plant presents a means of reducing both the volume and frequency of pesticide/fungicide application. The foliar uptake of the glucose-fipronil conjugate N-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine (GTF) achieved in castor bean (Ricinus communis) and its transport via the phloem are known to be mediated by monosaccharide transporter(s) [MST(s)], although neither the identity of the key MST(s) involved nor the mechanistic basis of its movement have yet to be described. On the basis of homology with Arabidopsis thaliana sugar transporters, the castor bean genome was concluded to harbor 53 genes encoding a sugar transporter, falling into the eight previously defined subfamilies INT, PMT, VGT, STP, ERD6, pGlucT, TMT, and SUT. Transcriptional profiling identified the product of RcSTP1 as a candidate for mediating GTF uptake, because this gene was induced by exposure of the plant to GTF. When RcSTP1 was transiently expressed in onion epidermis cells, the site of RcSTP1 deposition was shown to be the plasma membrane. A functional analysis based on RcSTP1 expression in Xenopus laevis oocytes demonstrated that its product has a high affinity for GTF. The long-distance root-to-shoot transport of GTF was enhanced in a transgenic soybean chimera constitutively expressing RcSTP1.
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Affiliation(s)
- Gen-Lin Mao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Yin Yan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Yan Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Bing-Feng Wang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Fei-Fei Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Zhi-Xiang Zhang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Fei Lin
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
| | - Han-Hong Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University , Guangzhou, Guangdong 510642, People's Republic of China
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50
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Tran TM, Hampton CS, Brossard TW, Harmata M, Robertson JD, Jurisson SS, Braun DM. In vivo transport of three radioactive [ 18F]-fluorinated deoxysucrose analogs by the maize sucrose transporter ZmSUT1. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 115:1-11. [PMID: 28300727 DOI: 10.1016/j.plaphy.2017.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 05/26/2023]
Abstract
Sucrose transporter (SUT) proteins translocate sucrose across cell membranes; however, mechanistic aspects of sucrose binding by SUTs are not well resolved. Specific hydroxyl groups in sucrose participate in hydrogen bonding with SUT proteins. We previously reported that substituting a radioactive fluorine-18 [18F] at the C-6' position within the fructosyl moiety of sucrose did not affect sucrose transport by the maize (Zea mays) ZmSUT1 protein. To determine how 18F substitution of hydroxyl groups at two other positions within sucrose, the C-1' in the fructosyl moiety or the C-6 in the glucosyl moiety, impact sucrose transport, we synthesized 1'-[F18]fluoro-1'-deoxysucrose and 6-[F18]fluoro-6-deoxysucrose ([18F]FDS) analogs. Each [18F]FDS derivative was independently introduced into wild-type or sut1 mutant plants, which are defective in sucrose phloem loading. All three (1'-, 6'-, and 6-) [18F]FDS derivatives were efficiently and equally translocated, similarly to carbon-14 [14C]-labeled sucrose. Hence, individually replacing the hydroxyl groups at these positions within sucrose does not interfere with substrate recognition, binding, or membrane transport processes, and hydroxyl groups at these three positions are not essential for hydrogen bonding between sucrose and ZmSUT1. [18F]FDS imaging afforded several advantages compared to [14C]-sucrose detection. We calculated that 1'-[18F]FDS was transported at approximately a rate of 0.90 ± 0.15 m.h-1 in wild-type leaves, and at 0.68 ± 0.25 m.h-1 in sut1 mutant leaves. Collectively, our data indicated that [18F]FDS analogs are valuable tools to probe sucrose-SUT interactions and to monitor sucrose transport in plants.
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Affiliation(s)
- Thu M Tran
- Plant Imaging Consortium, United States; Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO 65211, United States
| | - Carissa S Hampton
- Department of Chemistry, University of Missouri, Columbia, MO 65211, United States; University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211, United States
| | - Tom W Brossard
- Department of Chemistry, University of Missouri, Columbia, MO 65211, United States; University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211, United States
| | - Michael Harmata
- Department of Chemistry, University of Missouri, Columbia, MO 65211, United States
| | - J David Robertson
- Department of Chemistry, University of Missouri, Columbia, MO 65211, United States; University of Missouri Research Reactor, University of Missouri, Columbia, MO 65211, United States
| | - Silvia S Jurisson
- Plant Imaging Consortium, United States; Department of Chemistry, University of Missouri, Columbia, MO 65211, United States
| | - David M Braun
- Plant Imaging Consortium, United States; Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, Columbia, MO 65211, United States.
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