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Chen L, Ghannoum O, Furbank RT. Sugar sensing in C4 source leaves: a gap that needs to be filled. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3818-3834. [PMID: 38642398 PMCID: PMC11233418 DOI: 10.1093/jxb/erae166] [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: 10/11/2023] [Accepted: 04/18/2024] [Indexed: 04/22/2024]
Abstract
Plant growth depends on sugar production and export by photosynthesizing source leaves and sugar allocation and import by sink tissues (grains, roots, stems, and young leaves). Photosynthesis and sink demand are tightly coordinated through metabolic (substrate, allosteric) feedback and signalling (sugar, hormones) mechanisms. Sugar signalling integrates sugar production with plant development and environmental cues. In C3 plants (e.g. wheat and rice), it is well documented that sugar accumulation in source leaves, due to source-sink imbalance, negatively feeds back on photosynthesis and plant productivity. However, we have a limited understanding about the molecular mechanisms underlying those feedback regulations, especially in C4 plants (e.g. maize, sorghum, and sugarcane). Recent work with the C4 model plant Setaria viridis suggested that C4 leaves have different sugar sensing thresholds and behaviours relative to C3 counterparts. Addressing this research priority is critical because improving crop yield requires a better understanding of how plants coordinate source activity with sink demand. Here we review the literature, present a model of action for sugar sensing in C4 source leaves, and suggest ways forward.
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Affiliation(s)
- Lily Chen
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, NSW, 2753, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, NSW, 2753, Australia
| | - Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
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2
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Plackett ARG, Hibberd JM. Rice bundle sheath cell shape is regulated by the timing of light exposure during leaf development. PLANT, CELL & ENVIRONMENT 2024; 47:2597-2613. [PMID: 38549236 DOI: 10.1111/pce.14902] [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: 10/23/2023] [Revised: 02/14/2024] [Accepted: 03/16/2024] [Indexed: 06/06/2024]
Abstract
Plant leaves contain multiple cell types which achieve distinct characteristics whilst still coordinating development within the leaf. The bundle sheath possesses larger individual cells and lower chloroplast content than the adjacent mesophyll, but how this morphology is achieved remains unknown. To identify regulatory mechanisms determining bundle sheath cell morphology we tested the effects of perturbing environmental (light) and endogenous signals (hormones) during leaf development of Oryza sativa (rice). Total chloroplast area in bundle sheath cells was found to increase with cell size as in the mesophyll but did not maintain a 'set-point' relationship, with the longest bundle sheath cells demonstrating the lowest chloroplast content. Application of exogenous cytokinin and gibberellin significantly altered the relationship between cell size and chloroplast biosynthesis in the bundle sheath, increasing chloroplast content of the longest cells. Delayed exposure to light reduced the mean length of bundle sheath cells but increased corresponding leaf length, whereas premature light reduced final leaf length but did not affect bundle sheath cells. This suggests that the plant hormones cytokinin and gibberellin are regulators of the bundle sheath cell-chloroplast relationship and that final bundle sheath length may potentially be affected by light-mediated control of exit from the cell cycle.
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Affiliation(s)
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
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3
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Tee EE, Faulkner C. Plasmodesmata and intercellular molecular traffic control. THE NEW PHYTOLOGIST 2024; 243:32-47. [PMID: 38494438 DOI: 10.1111/nph.19666] [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: 10/30/2023] [Accepted: 02/13/2024] [Indexed: 03/19/2024]
Abstract
Plasmodesmata are plasma membrane-lined connections that join plant cells to their neighbours, establishing an intercellular cytoplasmic continuum through which molecules can travel between cells, tissues, and organs. As plasmodesmata connect almost all cells in plants, their molecular traffic carries information and resources across a range of scales, but dynamic control of plasmodesmal aperture can change the possible domains of molecular exchange under different conditions. Plasmodesmal aperture is controlled by specialised signalling cascades accommodated in spatially discrete membrane and cell wall domains. Thus, the composition of plasmodesmata defines their capacity for molecular trafficking. Further, their shape and density can likewise define trafficking capacity, with the cell walls between different cell types hosting different numbers and forms of plasmodesmata to drive molecular flux in physiologically important directions. The molecular traffic that travels through plasmodesmata ranges from small metabolites through to proteins, and possibly even larger mRNAs. Smaller molecules are transmitted between cells via passive mechanisms but how larger molecules are efficiently trafficked through plasmodesmata remains a key question in plasmodesmal biology. How plasmodesmata are formed, the shape they take, what they are made of, and what passes through them regulate molecular traffic through plants, underpinning a wide range of plant physiology.
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Affiliation(s)
- Estee E Tee
- Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Christine Faulkner
- Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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4
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Ouyang W, Wientjes E, van der Putten PEL, Caracciolo L, Zhao R, Agho C, Chiurazzi MJ, Bongers M, Struik PC, van Amerongen H, Yin X. Roles for leakiness and O 2 evolution in explaining lower-than-theoretical quantum yields of photosynthesis in the PEP-CK subtype of C 4 plants. THE NEW PHYTOLOGIST 2024; 242:431-443. [PMID: 38406986 DOI: 10.1111/nph.19614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Theoretically, the PEP-CK C4 subtype has a higher quantum yield of CO2 assimilation (Φ CO 2 ) than NADP-ME or NAD-ME subtypes because ATP required for operating the CO2-concentrating mechanism is believed to mostly come from the mitochondrial electron transport chain (mETC). However, reportedΦ CO 2 is not higher in PEP-CK than in the other subtypes. We hypothesise, more photorespiration, associated with higher leakiness and O2 evolution in bundle-sheath (BS) cells, cancels out energetic advantages in PEP-CK species. Nine species (two to four species per subtype) were evaluated by gas exchange, chlorophyll fluorescence, and two-photon microscopy to estimate the BS conductance (gbs) and leakiness using a biochemical model. Average gbs estimates were 2.9, 4.8, and 5.0 mmol m-2 s-1 bar-1, and leakiness values were 0.129, 0.179, and 0.180, in NADP-ME, NAD-ME, and PEP-CK species, respectively. The BS CO2 level was somewhat higher, O2 level was marginally lower, and thus, photorespiratory loss was slightly lower, in NADP-ME than in NAD-ME and PEP-CK species. Differences in these parameters existed among species within a subtype, and gbs was co-determined by biochemical decarboxylating sites and anatomical characteristics. Our hypothesis and results partially explain variations in observedΦ CO 2 , but suggest that PEP-CK species probably use less ATP from mETC than classically defined PEP-CK mechanisms.
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Affiliation(s)
- Wenjing Ouyang
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
- School of Agriculture, Yunnan University, Kunming, 650504, Yunnan, China
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Peter E L van der Putten
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Ludovico Caracciolo
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Ruixuan Zhao
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
- School of Agriculture, Yunnan University, Kunming, 650504, Yunnan, China
| | - Collins Agho
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Maurizio Junior Chiurazzi
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Marius Bongers
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
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5
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Liu Z, Cheng J. C 4 rice engineering, beyond installing a C 4 cycle. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108256. [PMID: 38091938 DOI: 10.1016/j.plaphy.2023.108256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 02/15/2024]
Abstract
C4 photosynthesis in higher plants is carried out by two distinct cell types: mesophyll cells and bundle sheath cells, as a result highly concentrated carbon dioxide is released surrounding RuBisCo in chloroplasts of bundle sheath cells and the photosynthetic efficiency is significantly higher than that of C3 plants. The evolution of the dual-cell C4 cycle involved complex modifications to leaf anatomy and cell ultra-structures. These include an increase in leaf venation, the formation of Kranz anatomy, changes in chloroplast morphology in bundle sheath cells, and increases in the density of plasmodesmata at interfaces between the bundle sheath and mesophyll cells. It is predicted that cereals will be in severe worldwide shortage at the mid-term of this century. Rice is a staple food that feeds more than half of the world's population. If rice can be engineered to perform C4 photosynthesis, it is estimated that rice yield will be increased by at least 50% due to enhanced photosynthesis. Thus, the Second Green Revolution has been launched on this principle by genetically installing C4 photosynthesis into C3 crops. The studies on molecular mechanisms underlying the changes in leaf morphoanatomy involved in C4 photosynthesis have made great progress in recent years. As there are plenty of reviews discussing the installment of the C4 cycle, we focus on the current progress and challenges posed to the research regarding leaf anatomy and cell ultra-structure modifications made towards the development of C4 rice.
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Affiliation(s)
- Zheng Liu
- State Key Laboratory of North China Crop Improvement and Regulation, College of Agronomy, Hebei Agricultural University, Baoding, 071001, China.
| | - Jinjin Cheng
- College of Agronomy, Shanxi Agricultural University, Jinzhong, 030801, China
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6
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Schreier TB, Müller KH, Eicke S, Faulkner C, Zeeman SC, Hibberd JM. Plasmodesmal connectivity in C 4 Gynandropsis gynandra is induced by light and dependent on photosynthesis. THE NEW PHYTOLOGIST 2024; 241:298-313. [PMID: 37882365 PMCID: PMC10952754 DOI: 10.1111/nph.19343] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 09/28/2023] [Indexed: 10/27/2023]
Abstract
In leaves of C4 plants, the reactions of photosynthesis become restricted between two compartments. Typically, this allows accumulation of C4 acids in mesophyll (M) cells and subsequent decarboxylation in the bundle sheath (BS). In C4 grasses, proliferation of plasmodesmata between these cell types is thought to increase cell-to-cell connectivity to allow efficient metabolite movement. However, it is not known whether C4 dicotyledons also show this enhanced plasmodesmal connectivity and so whether this is a general requirement for C4 photosynthesis is not clear. How M and BS cells in C4 leaves become highly connected is also not known. We investigated these questions using 3D- and 2D-electron microscopy on the C4 dicotyledon Gynandropsis gynandra as well as phylogenetically close C3 relatives. The M-BS interface of C4 G. gynandra showed higher plasmodesmal frequency compared with closely related C3 species. Formation of these plasmodesmata was induced by light. Pharmacological agents that perturbed photosynthesis reduced the number of plasmodesmata, but this inhibitory effect could be reversed by the provision of exogenous sucrose. We conclude that enhanced formation of plasmodesmata between M and BS cells is wired to the induction of photosynthesis in C4 G. gynandra.
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Affiliation(s)
- Tina B. Schreier
- Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB1 3EAUK
- Present address:
Department of BiologyUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Karin H. Müller
- Cambridge Advanced Imaging Centre (CAIC)University of CambridgeDowning StreetCambridgeCB2 3DYUK
| | - Simona Eicke
- Institute of Molecular Plant BiologyETH ZurichZurichCH‐8092Switzerland
| | - Christine Faulkner
- Cell and Developmental BiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Samuel C. Zeeman
- Institute of Molecular Plant BiologyETH ZurichZurichCH‐8092Switzerland
| | - Julian M. Hibberd
- Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB1 3EAUK
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7
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Baird AS, Taylor SH, Reddi S, Pasquet-Kok J, Vuong C, Zhang Y, Watcharamongkol T, John GP, Scoffoni C, Osborne CP, Sack L. Allometries of cell and tissue anatomy and photosynthetic rate across leaves of C 3 and C 4 grasses. PLANT, CELL & ENVIRONMENT 2024; 47:156-173. [PMID: 37876323 DOI: 10.1111/pce.14741] [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: 02/25/2023] [Revised: 06/26/2023] [Accepted: 10/09/2023] [Indexed: 10/26/2023]
Abstract
Allometric relationships among the dimensions of leaves and their cells hold across diverse eudicotyledons, but have remained untested in the leaves of grasses. We hypothesised that geometric (proportional) allometries of cell sizes across tissues and of leaf dimensions would arise due to the coordination of cell development and that of cell functions such as water, nutrient and energy transport, and that cell sizes across tissues would be associated with light-saturated photosynthetic rate. We tested predictions across 27 globally distributed C3 and C4 grass species grown in a common garden. We found positive relationships among average cell sizes within and across tissues, and of cell sizes with leaf dimensions. Grass leaf anatomical allometries were similar to those of eudicots, with exceptions consistent with the fewer cell layers and narrower form of grass leaves, and the specialised roles of epidermis and bundle sheath in storage and leaf movement. Across species, mean cell sizes in each tissue were associated with light-saturated photosynthetic rate per leaf mass, supporting the functional coordination of cell sizes. These findings highlight the generality of evolutionary allometries within the grass lineage and their interlinkage with coordinated development and function.
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Affiliation(s)
- Alec S Baird
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Samuel H Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Sachin Reddi
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Jessica Pasquet-Kok
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Christine Vuong
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Yu Zhang
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Teera Watcharamongkol
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
- Faculty of Science and Technology, Kanchanaburi Rajabhat University, Kanchanaburi, Thailand
| | - Grace P John
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Christine Scoffoni
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
- Department of Biological Sciences, California State University Los Angeles, Los Angeles, California, USA
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
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8
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Naziębło A, Merlak HM, Wierzbicka MH. The bundle sheath in Zea mays leaves functions as a protective barrier against the toxic effect of lead. JOURNAL OF PLANT PHYSIOLOGY 2023; 290:154104. [PMID: 37839393 DOI: 10.1016/j.jplph.2023.154104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 09/07/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
Lead is a highly toxic metal. It impairs the metabolism of living organisms. Plants show different sensitivity to the action of this element. One of the plants with relatively high lead tolerance is Zea mays, where even in detached leaves treated with Pb2+ ions, the photosynthesis rate remains very high compared to other plant species. This study set out to determine the mechanism responsible for the high resistance of maize photosynthetic tissue to the toxic effect of this metal. For this purpose, the cut leaves of Z. mays were incubated in Pb(NO3)2 solutions at different concentrations. Regions of lead accumulation in tissues and cells were located using histochemical methods and transmission electron microscopy. The experiments showed a diverse distribution of lead ions in the leaf blade of Z. mays. Most of the accumulated Pb2+ ions were observed in the vascular bundle and the bundle sheath, while minimal traces of metal were transferred to the mesophyll. In Pisum sativum leaves, although Pb(NO3)2 concentration in the solution was two-fold lower, lead accumulated in all the leaf tissues - mainly in the vascular bundle, epidermis, sclerenchyma, and mesophyll. Thus, bundle sheath cells in maize leaves were able to inhibit the flow of Pb2+ ions to the ground tissue. Therefore, the influence of the toxic metal on photosynthesis in mesophyll cells remained minimal. These experiments show that the structure of Z. mays leaf, with a layer of bundle sheath cells (characteristic of C4 plants), contributes to the protecting photosynthetic tissue against the toxic effect of lead.
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Affiliation(s)
- Aleksandra Naziębło
- Department of Ecotoxicology, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warszawa, Poland.
| | - Hanna M Merlak
- Department of Ecotoxicology, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warszawa, Poland
| | - Małgorzata H Wierzbicka
- Department of Ecotoxicology, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warszawa, Poland
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9
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Paterlini A. A year at the forefront of plasmodesmal biology. Biol Open 2023; 12:bio060123. [PMID: 37874138 PMCID: PMC10618598 DOI: 10.1242/bio.060123] [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: 10/25/2023] Open
Abstract
Cell-cell communication is a central feature of multicellular organisms, enabling division of labour and coordinated responses. Plasmodesmata are membrane-lined pores that provide regulated cytoplasmic continuity between plant cells, facilitating signalling and transport across neighboring cells. Plant development and survival profoundly depend on the existence and functioning of these structures, bringing them to the spotlight for both fundamental and applied research. Despite the rich conceptual and translational rewards in sight, however, the study of plasmodesmata poses significant challenges. This Review will mostly focus on research published between May 2022 and May 2023 and intends to provide a short overview of recent discoveries, innovations, community resources and hypotheses.
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Affiliation(s)
- Andrea Paterlini
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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10
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Benning UF, Chen L, Watson-Lazowski A, Henry C, Furbank RT, Ghannoum O. Spatial expression patterns of genes encoding sugar sensors in leaves of C4 and C3 grasses. ANNALS OF BOTANY 2023; 131:985-1000. [PMID: 37103118 PMCID: PMC10332396 DOI: 10.1093/aob/mcad057] [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: 12/15/2022] [Accepted: 04/26/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND AND AIMS The mechanisms of sugar sensing in grasses remain elusive, especially those using C4 photosynthesis even though a large proportion of the world's agricultural crops utilize this pathway. We addressed this gap by comparing the expression of genes encoding components of sugar sensors in C3 and C4 grasses, with a focus on source tissues of C4 grasses. Given C4 plants evolved into a two-cell carbon fixation system, it was hypothesized this may have also changed how sugars were sensed. METHODS For six C3 and eight C4 grasses, putative sugar sensor genes were identified for target of rapamycin (TOR), SNF1-related kinase 1 (SnRK1), hexokinase (HXK) and those involved in the metabolism of the sugar sensing metabolite trehalose-6-phosphate (T6P) using publicly available RNA deep sequencing data. For several of these grasses, expression was compared in three ways: source (leaf) versus sink (seed), along the gradient of the leaf, and bundle sheath versus mesophyll cells. KEY RESULTS No positive selection of codons associated with the evolution of C4 photosynthesis was identified in sugar sensor proteins here. Expressions of genes encoding sugar sensors were relatively ubiquitous between source and sink tissues as well as along the leaf gradient of both C4 and C3 grasses. Across C4 grasses, SnRK1β1 and TPS1 were preferentially expressed in the mesophyll and bundle sheath cells, respectively. Species-specific differences of gene expression between the two cell types were also apparent. CONCLUSIONS This comprehensive transcriptomic study provides an initial foundation for elucidating sugar-sensing genes within major C4 and C3 crops. This study provides some evidence that C4 and C3 grasses do not differ in how sugars are sensed. While sugar sensor gene expression has a degree of stability along the leaf, there are some contrasts between the mesophyll and bundle sheath cells.
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Affiliation(s)
- Urs F Benning
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales 2753, Australia
| | - Lily Chen
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales 2753, Australia
| | | | - Clemence Henry
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales 2753, Australia
| | - Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Oula Ghannoum
- Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales 2753, Australia
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11
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Daloso DDM, Morais EG, Oliveira E Silva KF, Williams TCR. Cell-type-specific metabolism in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:1093-1114. [PMID: 36987968 DOI: 10.1111/tpj.16214] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 05/31/2023]
Abstract
Every plant organ contains tens of different cell types, each with a specialized function. These functions are intrinsically associated with specific metabolic flux distributions that permit the synthesis of the ATP, reducing equivalents and biosynthetic precursors demanded by the cell. Investigating such cell-type-specific metabolism is complicated by the mosaic of different cells within each tissue combined with the relative scarcity of certain types. However, techniques for the isolation of specific cells, their analysis in situ by microscopy, or modeling of their function in silico have permitted insight into cell-type-specific metabolism. In this review we present some of the methods used in the analysis of cell-type-specific metabolism before describing what we know about metabolism in several cell types that have been studied in depth; (i) leaf source and sink cells; (ii) glandular trichomes that are capable of rapid synthesis of specialized metabolites; (iii) guard cells that must accumulate large quantities of the osmolytes needed for stomatal opening; (iv) cells of seeds involved in storage of reserves; and (v) the mesophyll and bundle sheath cells of C4 plants that participate in a CO2 concentrating cycle. Metabolism is discussed in terms of its principal features, connection to cell function and what factors affect the flux distribution. Demand for precursors and energy, availability of substrates and suppression of deleterious processes are identified as key factors in shaping cell-type-specific metabolism.
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Affiliation(s)
- Danilo de Menezes Daloso
- Lab Plant, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza-CA, 60451-970, Brazil
| | - Eva Gomes Morais
- Lab Plant, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza-CA, 60451-970, Brazil
| | - Karen Fernanda Oliveira E Silva
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade de Brasília, Asa Norte, Brasília-DF, 70910-900, Brazil
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12
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Wu H, Li Z. Nano-enabled agriculture: How do nanoparticles cross barriers in plants? PLANT COMMUNICATIONS 2022; 3:100346. [PMID: 35689377 PMCID: PMC9700125 DOI: 10.1016/j.xplc.2022.100346] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 05/12/2022] [Accepted: 06/06/2022] [Indexed: 05/15/2023]
Abstract
Nano-enabled agriculture is a topic of intense research interest. However, our knowledge of how nanoparticles enter plants, plant cells, and organelles is still insufficient. Here, we discuss the barriers that limit the efficient delivery of nanoparticles at the whole-plant and single-cell levels. Some commonly overlooked factors, such as light conditions and surface tension of applied nano-formulations, are discussed. Knowledge gaps regarding plant cell uptake of nanoparticles, such as the effect of electrochemical gradients across organelle membranes on nanoparticle delivery, are analyzed and discussed. The importance of controlling factors such as size, charge, stability, and dispersibility when properly designing nanomaterials for plants is outlined. We mainly focus on understanding how nanoparticles travel across barriers in plants and plant cells and the major factors that limit the efficient delivery of nanoparticles, promoting a better understanding of nanoparticle-plant interactions. We also provide suggestions on the design of nanomaterials for nano-enabled agriculture.
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Affiliation(s)
- Honghong Wu
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China; College of Agronomy and Biotechnology, China Agricultural University, Beijing 100083, China.
| | - Zhaohu Li
- MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China; College of Agronomy and Biotechnology, China Agricultural University, Beijing 100083, China.
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13
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Shen Q, Xie Y, Qiu X, Yu J. The era of cultivating smart rice with high light efficiency and heat tolerance has come of age. FRONTIERS IN PLANT SCIENCE 2022; 13:1021203. [PMID: 36275525 PMCID: PMC9585279 DOI: 10.3389/fpls.2022.1021203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
How to improve the yield of crops has always been the focus of breeding research. Due to the population growth and global climate change, the demand for food has increased sharply, which has brought great challenges to agricultural production. In order to make up for the limitation of global cultivated land area, it is necessary to further improve the output of crops. Photosynthesis is the main source of plant assimilate accumulation, which has a profound impact on the formation of its yield. This review focuses on the cultivation of high light efficiency plants, introduces the main technical means and research progress in improving the photosynthetic efficiency of plants, and discusses the main problems and difficulties faced by the cultivation of high light efficiency plants. At the same time, in view of the frequent occurrence of high-temperature disasters caused by global warming, which seriously threatened plant normal production, we reviewed the response mechanism of plants to heat stress, introduced the methods and strategies of how to cultivate heat tolerant crops, especially rice, and briefly reviewed the progress of heat tolerant research at present. Given big progress in these area, the era of cultivating smart rice with high light efficiency and heat tolerance has come of age.
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Affiliation(s)
- Qiuping Shen
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Zhejiang A & F University, Hangzhou, China
- College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Yujun Xie
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Zhejiang A & F University, Hangzhou, China
- College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Xinzhe Qiu
- College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
| | - Jinsheng Yu
- The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, Zhejiang A & F University, Hangzhou, China
- College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, China
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14
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Medeiros DB, Ishihara H, Guenther M, Rosado de Souza L, Fernie AR, Stitt M, Arrivault S. 13CO2 labeling kinetics in maize reveal impaired efficiency of C4 photosynthesis under low irradiance. PLANT PHYSIOLOGY 2022; 190:280-304. [PMID: 35751609 PMCID: PMC9434203 DOI: 10.1093/plphys/kiac306] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/06/2022] [Indexed: 06/01/2023]
Abstract
C4 photosynthesis allows faster photosynthetic rates and higher water and nitrogen use efficiency than C3 photosynthesis, but at the cost of lower quantum yield due to the energy requirement of its biochemical carbon concentration mechanism. It has also been suspected that its operation may be impaired in low irradiance. To investigate fluxes under moderate and low irradiance, maize (Zea mays) was grown at 550 µmol photons m-2 s-l and 13CO2 pulse-labeling was performed at growth irradiance or several hours after transfer to 160 µmol photons m-2 s-1. Analysis by liquid chromatography/tandem mass spectrometry or gas chromatography/mass spectrometry provided information about pool size and labeling kinetics for 32 metabolites and allowed estimation of flux at many steps in C4 photosynthesis. The results highlighted several sources of inefficiency in low light. These included excess flux at phosphoenolpyruvate carboxylase, restriction of decarboxylation by NADP-malic enzyme, and a shift to increased CO2 incorporation into aspartate, less effective use of metabolite pools to drive intercellular shuttles, and higher relative and absolute rates of photorespiration. The latter provides evidence for a lower bundle sheath CO2 concentration in low irradiance, implying that operation of the CO2 concentration mechanism is impaired in this condition. The analyses also revealed rapid exchange of carbon between the Calvin-Benson cycle and the CO2-concentration shuttle, which allows rapid adjustment of the balance between CO2 concentration and assimilation, and accumulation of large amounts of photorespiratory intermediates in low light that provides a major carbon reservoir to build up C4 metabolite pools when irradiance increases.
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Affiliation(s)
- David B Medeiros
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Hirofumi Ishihara
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Manuela Guenther
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | | | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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15
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Antreich SJ, Huss JC, Xiao N, Singh A, Gierlinger N. The walnut shell network: 3D visualisation of symplastic and apoplastic transport routes in sclerenchyma tissue. PLANTA 2022; 256:49. [PMID: 35881249 PMCID: PMC9325819 DOI: 10.1007/s00425-022-03960-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/06/2022] [Indexed: 05/16/2023]
Abstract
High symplastic connectivity via pits was linked to the lignification of the developing walnut shell. With maturation, this network lessened, whereas apoplastic intercellular space remained and became relevant for shell drying. The shell of the walnut (Juglans regia) sclerifies within several weeks. This fast secondary cell wall thickening and lignification of the shell tissue might need metabolites from the supporting husk tissue. To reveal the transport capacity of the walnut shell tissue and its connection to the husk, we visualised the symplastic and apoplastic transport routes during shell development by serial block face-SEM and 3D reconstruction. We found an extensive network of pit channels connecting the cells within the shell tissue, but even more towards the husk tissue. Each pit channel ended in a pit field, which was occupied by multiple plasmodesmata passing through the middle lamella. During shell development, secondary cell wall formation progressed towards the interior of the cell, leaving active pit channels open. In contrast, pit channels, which had no plasmodesmata connection to a neighbouring cell, got filled by cellulose layers from the inner cell wall lamellae. A comparison with other nut species showed that an extended network during sclerification seemed to be linked to high cell wall lignification and that the connectivity between cells got reduced with maturation. In contrast, intercellular spaces between cells remained unchanged during the entire sclerification process, allowing air and water to flow through the walnut shell tissue when mature. The connectivity between inner tissue and environment was essential during shell drying in the last month of nut development to avoid mould formation. The findings highlight how connectivity and transport work in developing walnut shell tissue and how finally in the mature state these structures influence shell mechanics, permeability, conservation and germination.
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Affiliation(s)
- Sebastian J Antreich
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria.
| | - Jessica C Huss
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Nannan Xiao
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Adya Singh
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
| | - Notburga Gierlinger
- Institute of Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, 1190, Vienna, Austria
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16
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Simpson CJC, Reeves G, Tripathi A, Singh P, Hibberd JM. Using breeding and quantitative genetics to understand the C4 pathway. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3072-3084. [PMID: 34747993 PMCID: PMC9126733 DOI: 10.1093/jxb/erab486] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/03/2021] [Indexed: 05/09/2023]
Abstract
Reducing photorespiration in C3 crops could significantly increase rates of photosynthesis and yield. One method to achieve this would be to integrate C4 photosynthesis into C3 species. This objective is challenging as it involves engineering incompletely understood traits into C3 leaves, including complex changes to their biochemistry, cell biology, and anatomy. Quantitative genetics and selective breeding offer underexplored routes to identify regulators of these processes. We first review examples of natural intraspecific variation in C4 photosynthesis as well as the potential for hybridization between C3 and C4 species. We then discuss how quantitative genetic approaches including artificial selection and genome-wide association could be used to better understand the C4 syndrome and in so doing guide the engineering of the C4 pathway into C3 crops.
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Affiliation(s)
- Conor J C Simpson
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Gregory Reeves
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Anoop Tripathi
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Pallavi Singh
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- Correspondence:
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17
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Sonmez MC, Ozgur R, Uzilday B, Turkan I, Ganie SA. Redox regulation in
C
3
and
C
4
plants during climate change and its implications on food security. Food Energy Secur 2022. [DOI: 10.1002/fes3.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
| | - Rengin Ozgur
- Department of Biology Faculty of Science Ege University Izmir Turkey
- Graduate School of Life Sciences Tohoku University Sendai Japan
| | - Baris Uzilday
- Department of Biology Faculty of Science Ege University Izmir Turkey
- Graduate School of Life Sciences Tohoku University Sendai Japan
| | - Ismail Turkan
- Department of Biology Faculty of Science Ege University Izmir Turkey
| | - Showkat Ahmad Ganie
- Plant Molecular Science and Centre of Systems and Synthetic Biology Department of Biological Sciences Royal Holloway University of London Egham UK
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18
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Khoshravesh R, Hoffmann N, Hanson DT. Leaf microscopy applications in photosynthesis research: identifying the gaps. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1868-1893. [PMID: 34986250 DOI: 10.1093/jxb/erab548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
Leaf imaging via microscopy has provided critical insights into research on photosynthesis at multiple junctures, from the early understanding of the role of stomata, through elucidating C4 photosynthesis via Kranz anatomy and chloroplast arrangement in single cells, to detailed explorations of diffusion pathways and light utilization gradients within leaves. In recent decades, the original two-dimensional (2D) explorations have begun to be visualized in three-dimensional (3D) space, revising our understanding of structure-function relationships between internal leaf anatomy and photosynthesis. In particular, advancing new technologies and analyses are providing fresh insight into the relationship between leaf cellular components and improving the ability to model net carbon fixation, water use efficiency, and metabolite turnover rate in leaves. While ground-breaking developments in imaging tools and techniques have expanded our knowledge of leaf 3D structure via high-resolution 3D and time-series images, there is a growing need for more in vivo imaging as well as metabolite imaging. However, these advances necessitate further improvement in microscopy sciences to overcome the unique challenges a green leaf poses. In this review, we discuss the available tools, techniques, challenges, and gaps for efficient in vivo leaf 3D imaging, as well as innovations to overcome these difficulties.
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Affiliation(s)
| | - Natalie Hoffmann
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - David T Hanson
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
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19
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Reagan BC, Dunlap JR, Burch-Smith TM. Focused Ion Beam-Scanning Electron Microscopy for Investigating Plasmodesmal Densities. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2457:109-123. [PMID: 35349135 DOI: 10.1007/978-1-0716-2132-5_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Plasmodesmata (PD) facilitate the exchange of nutrients and signaling molecules between neighboring plant cells, and they are therefore essential for proper growth and development. PD have been studied extensively in efforts to elucidate the ultrastructure of individual PD nanopores and the distribution of PD in a variety of cell walls. These studies often involved the use of serial ultrathin sections and manual quantification of PD by transmission electron microscopy (TEM). In recent years, a variety of techniques that offer more amenable approaches for quantifying PD distribution have been reported. Here, we describe the quantification of PD densities using the serial scanning electron microscopy technique called focused ion beam-scanning electron microscopy (FIB-SEM). For this, resin-embedded samples prepared by standard TEM methods undergo successive rounds of imaging by SEM interspersed with milling of the sample surface by a focused beam of gallium ions to reveal a new surface. In this way, the details of the sample are sequentially revealed and imaged. Over the course of a few hours, repetitive milling and imaging facilitates the automated collection of nanometer-resolution data of several μm of sample depth. FIB-SEM can be targeted to interrogate specific cell walls and cell wall junctions, and the subsequent three-dimensional renderings of the data can be used to visualize the ultrastructural details of the sample. PD densities can then be rapidly quantified by calculating the number of PD per μm2 of cell wall observed in the renderings.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA.,Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - John R Dunlap
- The Joint Institute for Advanced Materials, University of Tennessee, Knoxville, TN, USA
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA. .,Donald Danforth Plant Science Center, Saint Louis, MO, USA.
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20
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Fan Y, Scafaro AP, Asao S, Furbank RT, Agostino A, Day DA, von Caemmerer S, Danila FR, Rug M, Webb D, Lee J, Atkin OK. Dark respiration rates are not determined by differences in mitochondrial capacity, abundance and ultrastructure in C 4 leaves. PLANT, CELL & ENVIRONMENT 2022; 45:1257-1269. [PMID: 35048399 DOI: 10.1111/pce.14267] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Our understanding of the regulation of respiration in C4 plants, where mitochondria play different roles in the different types of C4 photosynthetic pathway, remains limited. We examined how leaf dark respiration rates (Rdark ), in the presence and absence of added malate, vary in monocots representing the three classical biochemical types of C4 photosynthesis (NADP-ME, NAD-ME and PCK) using intact leaves and extracted bundle sheath strands. In particular, we explored to what extent rates of Rdark are associated with mitochondrial number, volume and ultrastructure. Based on examination of a single species per C4 type, we found that the respiratory response of NAD-ME and PCK type bundle sheath strands to added malate was associated with differences in mitochondrial number, volume, and/or ultrastructure, while NADP-ME type bundle sheath strands did not respond to malate addition. In general, mitochondrial traits reflected the contributions mitochondria make to photosynthesis in the three C4 types. However, despite the obvious differences in mitochondrial traits, no clear correlation was observed between these traits and Rdark . We suggest that Rdark is primarily driven by cellular maintenance demands and not mitochondrial composition per se, in a manner that is somewhat independent of mitochondrial organic acid cycling in the light.
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Affiliation(s)
- Yuzhen Fan
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Andrew P Scafaro
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Shinichi Asao
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Robert T Furbank
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Antony Agostino
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - David A Day
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Susanne von Caemmerer
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Florence R Danila
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Melanie Rug
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Jiwon Lee
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Owen K Atkin
- Research School of Biology, ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- Research School of Biology, Division of Plant Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
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21
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Accelerated remodeling of the mesophyll-bundle sheath interface in the maize C4 cycle mutant leaves. Sci Rep 2022; 12:5057. [PMID: 35322159 PMCID: PMC8943126 DOI: 10.1038/s41598-022-09135-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 03/14/2022] [Indexed: 11/18/2022] Open
Abstract
C4 photosynthesis in the maize leaf involves the exchange of organic acids between mesophyll (M) and the bundle sheath (BS) cells. The transport is mediated by plasmodesmata embedded in the suberized cell wall. We examined the maize Kranz anatomy with a focus on the plasmodesmata and cell wall suberization with microscopy methods. In the young leaf zone where M and BS cells had indistinguishable proplastids, plasmodesmata were simple and no suberin was detected. In leaf zones where dimorphic chloroplasts were evident, the plasmodesma acquired sphincter and cytoplasmic sleeves, and suberin was discerned. These modifications were accompanied by a drop in symplastic dye mobility at the M-BS boundary. We compared the kinetics of chloroplast differentiation and the modifications in M-BS connectivity in ppdk and dct2 mutants where C4 cycle is affected. The rate of chloroplast diversification did not alter, but plasmodesma remodeling, symplastic transport inhibition, and cell wall suberization were observed from younger leaf zone in the mutants than in wild type. Our results indicate that inactivation of the C4 genes accelerated the changes in the M-BS interface, and the reduced permeability suggests that symplastic transport between M and BS could be regulated for normal operation of C4 cycle.
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22
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Borghi GL, Arrivault S, Günther M, Barbosa Medeiros D, Dell’Aversana E, Fusco GM, Carillo P, Ludwig M, Fernie AR, Lunn JE, Stitt M. Metabolic profiles in C3, C3-C4 intermediate, C4-like, and C4 species in the genus Flaveria. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1581-1601. [PMID: 34910813 PMCID: PMC8890617 DOI: 10.1093/jxb/erab540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/14/2021] [Indexed: 05/22/2023]
Abstract
C4 photosynthesis concentrates CO2 around Rubisco in the bundle sheath, favouring carboxylation over oxygenation and decreasing photorespiration. This complex trait evolved independently in >60 angiosperm lineages. Its evolution can be investigated in genera such as Flaveria (Asteraceae) that contain species representing intermediate stages between C3 and C4 photosynthesis. Previous studies have indicated that the first major change in metabolism probably involved relocation of glycine decarboxylase and photorespiratory CO2 release to the bundle sheath and establishment of intercellular shuttles to maintain nitrogen stoichiometry. This was followed by selection for a CO2-concentrating cycle between phosphoenolpyruvate carboxylase in the mesophyll and decarboxylases in the bundle sheath, and relocation of Rubisco to the latter. We have profiled 52 metabolites in nine Flaveria species and analysed 13CO2 labelling patterns for four species. Our results point to operation of multiple shuttles, including movement of aspartate in C3-C4 intermediates and a switch towards a malate/pyruvate shuttle in C4-like species. The malate/pyruvate shuttle increases from C4-like to complete C4 species, accompanied by a rise in ancillary organic acid pools. Our findings support current models and uncover further modifications of metabolism along the evolutionary path to C4 photosynthesis in the genus Flaveria.
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Affiliation(s)
- Gian Luca Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
- Correspondence:
| | - Manuela Günther
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - David Barbosa Medeiros
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Emilia Dell’Aversana
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Giovanna Marta Fusco
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Petronia Carillo
- Universitá degli Studi della Campania, Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Via Vivaldi 43, 81100 Caserta, Italy
| | - Martha Ludwig
- The University of Western Australia, School of Molecular Sciences, 35 Stirling Highway, 6009 Perth, Australia
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - John E Lunn
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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23
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Miras M, Pottier M, Schladt TM, Ejike JO, Redzich L, Frommer WB, Kim JY. Plasmodesmata and their role in assimilate translocation. JOURNAL OF PLANT PHYSIOLOGY 2022; 270:153633. [PMID: 35151953 DOI: 10.1016/j.jplph.2022.153633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
During multicellularization, plants evolved unique cell-cell connections, the plasmodesmata (PD). PD of angiosperms are complex cellular domains, embedded in the cell wall and consisting of multiple membranes and a large number of proteins. From the beginning, it had been assumed that PD provide passage for a wide range of molecules, from ions to metabolites and hormones, to RNAs and even proteins. In the context of assimilate allocation, it has been hypothesized that sucrose produced in mesophyll cells is transported via PD from cell to cell down a concentration gradient towards the phloem. Entry into the sieve element companion cell complex (SECCC) is then mediated on three potential routes, depending on the species and conditions, - either via diffusion across PD, after conversion to raffinose via PD using a polymer trap mechanism, or via a set of transporters which secrete sucrose from one cell and secondary active uptake into the SECCC. Multiple loading mechanisms can likely coexist. We here review the current knowledge regarding photoassimilate transport across PD between cells as a prerequisite for translocation from leaves to recipient organs, in particular roots and developing seeds. We summarize the state-of-the-art in protein composition, structure, transport mechanism and regulation of PD to apprehend their functions in carbohydrate allocation. Since many aspects of PD biology remain elusive, we highlight areas that require new approaches and technologies to advance our understanding of these enigmatic and important cell-cell connections.
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Affiliation(s)
- Manuel Miras
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Mathieu Pottier
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - T Moritz Schladt
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - J Obinna Ejike
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Laura Redzich
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
| | - Wolf B Frommer
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany; Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
| | - Ji-Yun Kim
- Institute for Molecular Physiology and Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine-University Düsseldorf, Düsseldorf, 40225, Germany
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24
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Bilska-Kos A, Pietrusińska A, Suski S, Niedziela A, Linkiewicz AM, Majtkowski W, Żurek G, Zebrowski J. Cell Wall Properties Determine Genotype-Specific Response to Cold in Miscanthus × giganteus Plants. Cells 2022; 11:547. [PMID: 35159356 PMCID: PMC8834381 DOI: 10.3390/cells11030547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 01/05/2023] Open
Abstract
The cell wall plays a crucial role in plant growth and development, including in response to environmental factors, mainly through significant biochemical and biomechanical plasticity. The involvement of the cell wall in C4 plants' response to cold is, however, still poorly understood. Miscanthus × giganteus, a perennial grass, is generally considered cold tolerant and, in contrast to other thermophilic species such as maize or sorgo, can maintain a relatively high level of photosynthesis efficiency at low ambient temperatures. This unusual response to chilling among C4 plants makes Miscanthus an interesting study object in cold acclimation mechanism research. Using the results obtained from employing a diverse range of techniques, including analysis of plasmodesmata ultrastructure by means of transmission electron microscopy (TEM), infrared spectroscopy (FTIR), and biomechanical tests coupled with photosynthetic parameters measurements, we present evidence for the implication of the cell wall in genotype-specific responses to cold in this species. The observed reduction in the assimilation rate and disturbance of chlorophyll fluorescence parameters in the susceptible M3 genotype under cold conditions were associated with changes in the ultrastructure of the plasmodesmata, i.e., a constriction of the cytoplasmic sleeve in the central region of the microchannel at the mesophyll-bundle sheath interface. Moreover, this cold susceptible genotype was characterized by enhanced tensile stiffness, strength of leaf wall material, and a less altered biochemical profile of the cell wall, revealed by FTIR spectroscopy, compared to cold tolerant genotypes. These changes indicate that a decline in photosynthetic activity may result from a decrease in leaf CO2 conductance due to the formation of more compact and thicker cell walls and that an enhanced tolerance to cold requires biochemical wall remodelling. Thus, the well-established trade-off between photosynthetic capacity and leaf biomechanics found across multiple species in ecological research may also be a relevant factor in Miscanthus' tolerance to cold. In this paper, we demonstrate that M. giganteus genotypes showing a high degree of genetic similarity may respond differently to cold stress if exposed at earlier growing seasons to various temperature regimes, which has implications for the cell wall modifications patterns.
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Affiliation(s)
- Anna Bilska-Kos
- Department of Biochemistry and Biotechnology, Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland;
| | - Aleksandra Pietrusińska
- National Centre for Plant Genetic Resources, Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland;
| | - Szymon Suski
- Laboratory of Electron Microscopy, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur, 02-093 Warsaw, Poland;
| | - Agnieszka Niedziela
- Department of Biochemistry and Biotechnology, Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland;
| | - Anna M. Linkiewicz
- Molecular Biology and Genetics Department, Institute of Biological Sciences, Faculty of Biology and Environmental Sciences, Cardinal Stefan Wyszyński University, Wóycickiego 1/3, 01-938 Warsaw, Poland;
- Genetically Modified Organisms Controlling Laboratory, Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland
| | - Włodzimierz Majtkowski
- Botanical Garden, National Centre for Plant Genetic Resources, Plant Breeding and Acclimatization Institute—National Research Institute, Jeździecka 5, 85-867 Bydgoszcz, Poland;
| | - Grzegorz Żurek
- Department of Bioenergetics, Quality Analysis and Seed Science, Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland;
| | - Jacek Zebrowski
- Institute of Biology and Biotechnology, University of Rzeszów, Aleja Rejtana 16c, 35-959 Rzeszów, Poland;
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Chen L, Ganguly DR, Shafik SH, Ermakova M, Pogson BJ, Grof CPL, Sharwood RE, Furbank RT. Elucidating the role of SWEET13 in phloem loading of the C 4 grass Setaria viridis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:615-632. [PMID: 34780111 DOI: 10.1111/tpj.15581] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/11/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Photosynthetic efficiency and sink demand are tightly correlated with rates of phloem loading, where maintaining low cytosolic sugar concentrations is paramount to prevent the downregulation of photosynthesis. Sugars Will Eventually be Exported Transporters (SWEETs) are thought to have a pivotal role in the apoplastic phloem loading of C4 grasses. SWEETs have not been well studied in C4 species, and their investigation is complicated by photosynthesis taking place across two cell types and, therefore, photoassimilate export can occur from either one. SWEET13 homologues in C4 grasses have been proposed to facilitate apoplastic phloem loading. Here, we provide evidence for this hypothesis using the C4 grass Setaria viridis. Expression analyses on the leaf gradient of C4 species Setaria and Sorghum bicolor show abundant transcript levels for SWEET13 homologues. Carbohydrate profiling along the Setaria leaf shows total sugar content to be significantly higher in the mature leaf tip compared with the younger tissue at the base. We present the first known immunolocalization results for SvSWEET13a and SvSWEET13b using novel isoform-specific antisera. These results show localization to the bundle sheath and phloem parenchyma cells of both minor and major veins. We further present the first transport kinetics study of C4 monocot SWEETs by using a Xenopus laevis oocyte heterologous expression system. We demonstrate that SvSWEET13a and SvSWEET13b are high-capacity transporters of glucose and sucrose, with a higher apparent Vmax for sucrose, compared with glucose, typical of clade III SWEETs. Collectively, these results provide evidence for an apoplastic phloem loading pathway in Setaria and possibly other C4 species.
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Affiliation(s)
- Lily Chen
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- School of Science, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales, 2753, Australia
| | - Diep R Ganguly
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- CSIRO Synthetic Biology Future Science Platform, Canberra, Australian Capital Territory, 2601, Australia
| | - Sarah H Shafik
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Maria Ermakova
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Barry J Pogson
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Christopher P L Grof
- Centre for Plant Science, School of Environmental and Life Sciences, College of Engineering Science and Environment, University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - Robert E Sharwood
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- School of Science, Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales, 2753, Australia
| | - Robert T Furbank
- Research School of Biology, ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
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Danila FR. Measuring Plasmodesmata Density on Cell Interfaces of Monocot Leaves Using 3D Immunolocalization and Scanning Electron Microscopy. Methods Mol Biol 2022; 2457:125-142. [PMID: 35349136 DOI: 10.1007/978-1-0716-2132-5_7] [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: 06/14/2023]
Abstract
Quantification of plasmodesmata density on cell interfaces of plant tissues, particularly of leaves, has been a long-standing challenge. Using electron microscopy alone to quantify plasmodesmata is difficult because of the limited surface area coverage per image and hence the need to examine large numbers of sections for robust quantification. Fluorescence microscopy provides the larger surface area coverage per image but can only visualize pit fields and not individual plasmodesma. Moreover, in pigmented tissue like leaves, imaging cell interfaces beyond the epidermal layer would also require accurate sectioning. The advent of tissue clearing techniques such as PEA-CLARITY provided the opportunity to capture all pit fields within the leaf without resorting to sectioning. This paved the way toward the development of a more robust and precise plasmodesmata density quantification method by combining the three-dimensional immunolocalization fluorescence microscopy with scanning electron microscopy (SEM). Here, I describe a protocol to quantify plasmodesmata density on cell interfaces between mesophyll and bundle sheath in C3 and C4 monocot leaves.
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Affiliation(s)
- Florence R Danila
- Research School of Biology, The Australian National University, Acton, ACT, Australia.
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Paterlini A, Belevich I. Serial Block Electron Microscopy to Study Plasmodesmata in the Vasculature of Arabidopsis thaliana Roots. Methods Mol Biol 2022; 2457:95-107. [PMID: 35349134 DOI: 10.1007/978-1-0716-2132-5_5] [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: 06/14/2023]
Abstract
Serial block electron microscopy (SB-EM) is a technique that enables acquisition and reconstruction of 3D cellular volumes. The approach is valuable for the study of plasmodesmata (PD) as the relative positions of these structures are contained in the datasets. In this chapter, we describe how to prepare plant roots for SB-EM via fixation, embedding, and trimming steps. We also provide details and recommendations for later image acquisition and processing. The procedure is suitable to work on root vascular tissues.
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Affiliation(s)
| | - Ilya Belevich
- Helsinki Institute of Life Science/Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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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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Cui H. Challenges and Approaches to Crop Improvement Through C3-to-C4 Engineering. FRONTIERS IN PLANT SCIENCE 2021; 12:715391. [PMID: 34594351 PMCID: PMC8476962 DOI: 10.3389/fpls.2021.715391] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/06/2021] [Indexed: 05/24/2023]
Abstract
With a rapidly growing world population and dwindling natural resources, we are now facing the enormous challenge of increasing crop yields while simultaneously improving the efficiency of resource utilization. Introduction of C4 photosynthesis into C3 crops is widely accepted as a key strategy to meet this challenge because C4 plants are more efficient than C3 plants in photosynthesis and resource usage, particularly in hot climates, where the potential for productivity is high. Lending support to the feasibility of this C3-to-C4 engineering, evidence indicates that C4 photosynthesis has evolved from C3 photosynthesis in multiple lineages. Nevertheless, C3-to-C4 engineering is not an easy task, as several features essential to C4 photosynthesis must be introduced into C3 plants. One such feature is the spatial separation of the two phases of photosynthesis (CO2 fixation and carbohydrate synthesis) into the mesophyll and bundle sheath cells, respectively. Another feature is the Kranz anatomy, characterized by a close association between the mesophyll and bundle sheath (BS) cells (1:1 ratio). These anatomical features, along with a C4-specific carbon fixation enzyme (PEPC), form a CO2-concentration mechanism that ensures a high photosynthetic efficiency. Much effort has been taken in the past to introduce the C4 mechanism into C3 plants, but none of these attempts has met with success, which is in my opinion due to a lack of system-level understanding and manipulation of the C3 and C4 pathways. As a prerequisite for the C3-to-C4 engineering, I propose that not only the mechanisms that control the Kranz anatomy and cell-type-specific expression in C3 and C4 plants must be elucidated, but also a good understanding of the gene regulatory network underlying C3 and C4 photosynthesis must be achieved. In this review, I first describe the past and current efforts to increase photosynthetic efficiency in C3 plants and their limitations; I then discuss a systems approach to tackling down this challenge, some practical issues, and recent technical innovations that would help us to solve these problems.
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Affiliation(s)
- Hongchang Cui
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
- College of Life Science, Northwest Science University of Agriculture and Forestry, Yangling, China
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30
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Tofanello VR, Andrade LM, Flores-Borges DNA, Kiyota E, Mayer JLS, Creste S, Machado EC, Yin X, Struik PC, Ribeiro RV. Role of bundle sheath conductance in sustaining photosynthesis competence in sugarcane plants under nitrogen deficiency. PHOTOSYNTHESIS RESEARCH 2021; 149:275-287. [PMID: 34091828 DOI: 10.1007/s11120-021-00848-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 05/13/2021] [Indexed: 06/12/2023]
Abstract
The role of bundle sheath conductance (gbs) in sustaining sugarcane photosynthesis under nitrogen deficiency was investigated. Sugarcane was grown under different levels of nitrogen supply and gbs was estimated using simultaneous measurements of leaf gas exchange and chlorophyll fluorescence at 21% or 2% [O2] and varying air [CO2] and light intensity. Maximum rates of PEPC carboxylation, Rubisco carboxylation, and ATP production increased with an increase in leaf nitrogen concentration (LNC) from 1 to 3 g m-2. Low nitrogen supply reduced Rubisco and PEPC abundancies, the quantum efficiency of CO2 assimilation and gbs. Because of reduced gbs, low photosynthetic rates were not associated with increased leakiness under nitrogen deficiency. In fact, low nitrogen supply increased bundle sheath cell wall thickness, probably accounting for low gbs and increased estimates of [CO2] at Rubisco sites. Effects of nitrogen on expression of ShPIP2;1 and ShPIP1;2 aquaporins did not explain changes in gbs. Our data revealed that reduced Rubisco carboxylation was the main factor causing low sugarcane photosynthesis at low nitrogen supply, in contrast to the previous report on the importance of an impaired CO2 concentration mechanism under N deficiency. Our findings suggest higher investment of nitrogen into Rubisco protein would favour photosynthesis and plant performance under low nitrogen availability.
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Affiliation(s)
- Vanessa R Tofanello
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Larissa M Andrade
- Centro de Cana, Instituto Agronômico (IAC), Ribeirão Preto, SP, Brazil
| | - Denisele N A Flores-Borges
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Eduardo Kiyota
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Juliana L S Mayer
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Silvana Creste
- Centro de Cana, Instituto Agronômico (IAC), Ribeirão Preto, SP, Brazil
| | - Eduardo C Machado
- Laboratory of Plant Physiology "Coaracy M. Franco", Center for Research and Development in Ecophysiology and Biophysics, IAC, Campinas, SP, Brazil
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Dept. Plant Sciences, Wageningen University & Research, Wageningen, The Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Dept. Plant Sciences, Wageningen University & Research, Wageningen, The Netherlands
| | - Rafael V Ribeiro
- Laboratory of Crop Physiology (LCroP), Dept. Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Voitsekhovskaja OV, Melnikova AN, Demchenko KN, Ivanova AN, Dmitrieva VA, Maksimova AI, Lohaus G, Tomos AD, Tyutereva EV, Koroleva OA. Leaf Epidermis: The Ambiguous Symplastic Domain. FRONTIERS IN PLANT SCIENCE 2021; 12:695415. [PMID: 34394148 PMCID: PMC8358407 DOI: 10.3389/fpls.2021.695415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
The ability to develop secondary (post-cytokinetic) plasmodesmata (PD) is an important evolutionary advantage that helps in creating symplastic domains within the plant body. Developmental regulation of secondary PD formation is not completely understood. In flowering plants, secondary PD occur exclusively between cells from different lineages, e.g., at the L1/L2 interface within shoot apices, or between leaf epidermis (L1-derivative), and mesophyll (L2-derivative). However, the highest numbers of secondary PD occur in the minor veins of leaf between bundle sheath cells and phloem companion cells in a group of plant species designated "symplastic" phloem loaders, as opposed to "apoplastic" loaders. This poses a question of whether secondary PD formation is upregulated in general in symplastic loaders. Distribution of PD in leaves and in shoot apices of two symplastic phloem loaders, Alonsoa meridionalis and Asarina barclaiana, was compared with that in two apoplastic loaders, Solanum tuberosum (potato) and Hordeum vulgare (barley), using immunolabeling of the PD-specific proteins and transmission electron microscopy (TEM), respectively. Single-cell sampling was performed to correlate sugar allocation between leaf epidermis and mesophyll to PD abundance. Although the distribution of PD in the leaf lamina (except within the vascular tissues) and in the meristem layers was similar in all species examined, far fewer PD were found at the epidermis/epidermis and mesophyll/epidermis boundaries in apoplastic loaders compared to symplastic loaders. In the latter, the leaf epidermis accumulated sugar, suggesting sugar import from the mesophyll via PD. Thus, leaf epidermis and mesophyll might represent a single symplastic domain in Alonsoa meridionalis and Asarina barclaiana.
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Affiliation(s)
- Olga V. Voitsekhovskaja
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Göttingen, Germany
| | - Anna N. Melnikova
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
- Saint Petersburg State University, Saint Petersburg, Russia
| | - Kirill N. Demchenko
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Alexandra N. Ivanova
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
- Saint Petersburg State University, Saint Petersburg, Russia
| | - Valeria A. Dmitrieva
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
| | | | - Gertrud Lohaus
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Göttingen, Germany
- Molecular Plant Research/Plant Biochemistry, School of Mathematics and Natural Sciences, University of Wuppertal, Wuppertal, Germany
| | - A. Deri Tomos
- School of Biological Sciences, Bangor University, Bangor, United Kingdom
| | - Elena V. Tyutereva
- Komarov Botanical Institute, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Olga A. Koroleva
- School of Biological Sciences, Bangor University, Bangor, United Kingdom
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Clarke VC, Danila FR, von Caemmerer S. CO 2 diffusion in tobacco: a link between mesophyll conductance and leaf anatomy. Interface Focus 2021; 11:20200040. [PMID: 33628426 PMCID: PMC7898150 DOI: 10.1098/rsfs.2020.0040] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2020] [Indexed: 12/28/2022] Open
Abstract
The partial pressure of CO2 at the sites of carboxylation within chloroplasts depends on the conductance to CO2 diffusion from intercellular airspace to the sites of carboxylation, termed mesophyll conductance (gm). We investigated how gm varies with leaf age and through a tobacco (Nicotiana tabacum) canopy by combining gas exchange and carbon isotope measurements using tunable diode laser spectroscopy. We combined these measurements with the anatomical characterization of leaves. CO2 assimilation rate, A, and gm decreased as leaves aged and moved lower in the canopy and were linearly correlated. This was accompanied by large anatomical changes including an increase in leaf thickness. Chloroplast surface area exposed to the intercellular airspace per unit leaf area (Sc) also decreased lower in the canopy. Older leaves had thicker mesophyll cell walls and gm was inversely proportional to cell wall thickness. We conclude that reduced gm of older leaves lower in the canopy was associated with a reduction in Sc and a thickening of mesophyll cell walls.
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Affiliation(s)
- Victoria C Clarke
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Florence R Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
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33
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Danila FR, Thakur V, Chatterjee J, Bala S, Coe RA, Acebron K, Furbank RT, von Caemmerer S, Quick WP. Bundle sheath suberisation is required for C 4 photosynthesis in a Setaria viridis mutant. Commun Biol 2021; 4:254. [PMID: 33637850 PMCID: PMC7910553 DOI: 10.1038/s42003-021-01772-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 02/01/2021] [Indexed: 02/05/2023] Open
Abstract
C4 photosynthesis provides an effective solution for overcoming the catalytic inefficiency of Rubisco. The pathway is characterised by a biochemical CO2 concentrating mechanism that operates across mesophyll and bundle sheath (BS) cells and relies on a gas tight BS compartment. A screen of a mutant population of Setaria viridis, an NADP-malic enzyme type C4 monocot, generated using N-nitroso-N-methylurea identified a mutant with an amino acid change in the gene coding region of the ABCG transporter, a step in the suberin synthesis pathway. Here, Nile red staining, TEM, and GC/MS confirmed the alteration in suberin deposition in the BS cell wall of the mutant. We show that this has disrupted the suberin lamellae of BS cell wall and increased BS conductance to CO2 diffusion more than two-fold in the mutant. Consequently, BS CO2 partial pressure is reduced and CO2 assimilation was impaired in the mutant. Our findings provide experimental evidence that a functional suberin lamellae is an essential anatomical feature for efficient C4 photosynthesis in NADP-ME plants like S. viridis and have implications for engineering strategies to ensure future food security.
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Affiliation(s)
- Florence R Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia.
| | - Vivek Thakur
- Department of Systems and Computational Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Jolly Chatterjee
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Soumi Bala
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Robert A Coe
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Kelvin Acebron
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - William Paul Quick
- International Rice Research Institute, Los Baños, Laguna, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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34
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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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35
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Wang X, Sager R, Lee JY. Evaluating molecular movement through plasmodesmata. Methods Cell Biol 2020; 160:99-117. [PMID: 32896335 DOI: 10.1016/bs.mcb.2020.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Plasmodesmata are membrane-lined cytoplasmic passageways that facilitate the movement of nutrients and various types of molecules between cells in the plant. They are highly dynamic channels, opening or closing in response to physiological and developmental stimuli or environmental challenges such as biotic and abiotic stresses. Accumulating evidence supports the idea that such dynamic controls occur through integrative cellular mechanisms. Currently, a few fluorescence-based methods are available that allow monitoring changes in molecular movement through plasmodesmata. In this chapter, following a brief introduction to those methods, we provide a detailed step-by-step protocol for the Drop-ANd-See (DANS) assay, which is advantageous when it is desirable to measure plasmodesmal permeability non-invasively, in situ and in real-time. We discuss the experimental conditions one should consider to produce reliable and reproducible DANS results along with troubleshooting ideas.
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Affiliation(s)
- Xu Wang
- Department of Plant Physiology and Biochemistry, University of Hohenheim, Stuttgart, Germany
| | - Ross Sager
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Jung-Youn Lee
- Department of Plant and Soil Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States.
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Paterlini A, Belevich I, Jokitalo E, Helariutta Y. Computational Tools for Serial Block Electron Microscopy Reveal Plasmodesmata Distributions and Wall Environments. PLANT PHYSIOLOGY 2020; 184:53-64. [PMID: 32719057 PMCID: PMC7479905 DOI: 10.1104/pp.20.00396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/14/2020] [Indexed: 05/10/2023]
Abstract
Plasmodesmata are small channels that connect plant cells. While recent technological advances have facilitated analysis of the ultrastructure of these channels, there are limitations to efficiently addressing their presence over an entire cellular interface. Here, we highlight the value of serial block electron microscopy for this purpose. We developed a computational pipeline to study plasmodesmata distributions and detect the presence/absence of plasmodesmata clusters, or pit fields, at the phloem unloading interfaces of Arabidopsis (Arabidopsis thaliana) roots. Pit fields were visualized and quantified. As the wall environment of plasmodesmata is highly specialized, we also designed a tool to extract the thickness of the extracellular matrix at and outside of plasmodesmata positions. We detected and quantified clear wall thinning around plasmodesmata with differences between genotypes, including the recently published plm-2 sphingolipid mutant. Our tools open avenues for quantitative approaches in the analysis of symplastic trafficking.
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Affiliation(s)
- Andrea Paterlini
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR United Kingdom
| | - Ilya Belevich
- Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Eija Jokitalo
- Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
| | - Yrjö Helariutta
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR United Kingdom
- Helsinki Institute of Life Science, University of Helsinki, 00014 Helsinki, Finland
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Young SNR, Sack L, Sporck-Koehler MJ, Lundgren MR. Why is C4 photosynthesis so rare in trees? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4629-4638. [PMID: 32409834 PMCID: PMC7410182 DOI: 10.1093/jxb/eraa234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 05/12/2020] [Indexed: 05/08/2023]
Abstract
Since C4 photosynthesis was first discovered >50 years ago, researchers have sought to understand how this complex trait evolved from the ancestral C3 photosynthetic machinery on >60 occasions. Despite its repeated emergence across the plant kingdom, C4 photosynthesis is notably rare in trees, with true C4 trees only existing in Euphorbia. Here we consider aspects of the C4 trait that could limit but not preclude the evolution of a C4 tree, including reduced quantum yield, increased energetic demand, reduced adaptive plasticity, evolutionary constraints, and a new theory that the passive symplastic phloem loading mechanism observed in trees, combined with difficulties in maintaining sugar and water transport over a long pathlength, could make C4 photosynthesis largely incompatible with the tree lifeform. We conclude that the transition to a tree habit within C4 lineages as well as the emergence of C4 photosynthesis within pre-existing trees would both face a series of challenges that together explain the global rarity of C4 photosynthesis in trees. The C4 trees in Euphorbia are therefore exceptional in how they have circumvented every potential barrier to the rare C4 tree lifeform.
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Affiliation(s)
- Sophie N R Young
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Marjorie R Lundgren
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
- Correspondence:
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Cesarino I, Dello Ioio R, Kirschner GK, Ogden MS, Picard KL, Rast-Somssich MI, Somssich M. Plant science's next top models. ANNALS OF BOTANY 2020; 126:1-23. [PMID: 32271862 PMCID: PMC7304477 DOI: 10.1093/aob/mcaa063] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 04/08/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Model organisms are at the core of life science research. Notable examples include the mouse as a model for humans, baker's yeast for eukaryotic unicellular life and simple genetics, or the enterobacteria phage λ in virology. Plant research was an exception to this rule, with researchers relying on a variety of non-model plants until the eventual adoption of Arabidopsis thaliana as primary plant model in the 1980s. This proved to be an unprecedented success, and several secondary plant models have since been established. Currently, we are experiencing another wave of expansion in the set of plant models. SCOPE Since the 2000s, new model plants have been established to study numerous aspects of plant biology, such as the evolution of land plants, grasses, invasive and parasitic plant life, adaptation to environmental challenges, and the development of morphological diversity. Concurrent with the establishment of new plant models, the advent of the 'omics' era in biology has led to a resurgence of the more complex non-model plants. With this review, we introduce some of the new and fascinating plant models, outline why they are interesting subjects to study, the questions they will help to answer, and the molecular tools that have been established and are available to researchers. CONCLUSIONS Understanding the molecular mechanisms underlying all aspects of plant biology can only be achieved with the adoption of a comprehensive set of models, each of which allows the assessment of at least one aspect of plant life. The model plants described here represent a step forward towards our goal to explore and comprehend the diversity of plant form and function. Still, several questions remain unanswered, but the constant development of novel technologies in molecular biology and bioinformatics is already paving the way for the next generation of plant models.
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Affiliation(s)
- Igor Cesarino
- Department of Botany, Institute of Biosciences, University of São Paulo, Rua do Matão 277, Butantã, São Paulo, Brazil
| | - Raffaele Dello Ioio
- Dipartimento di Biologia e Biotecnologie, Università di Roma La Sapienza, Rome, Italy
| | - Gwendolyn K Kirschner
- University of Bonn, Institute of Crop Science and Resource Conservation (INRES), Division of Crop Functional Genomics, Bonn, Germany
| | - Michael S Ogden
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Kelsey L Picard
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Madlen I Rast-Somssich
- School of Biological Sciences, Monash University, Clayton Campus, Melbourne, VIC, Australia
| | - Marc Somssich
- School of BioSciences, University of Melbourne, Parkville, VIC, Australia
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Abstract
C4 photosynthesis evolved multiple times independently from ancestral C3 photosynthesis in a broad range of flowering land plant families and in both monocots and dicots. The evolution of C4 photosynthesis entails the recruitment of enzyme activities that are not involved in photosynthetic carbon fixation in C3 plants to photosynthesis. This requires a different regulation of gene expression as well as a different regulation of enzyme activities in comparison to the C3 context. Further, C4 photosynthesis relies on a distinct leaf anatomy that differs from that of C3, requiring a differential regulation of leaf development in C4. We summarize recent progress in the understanding of C4-specific features in evolution and metabolic regulation in the context of C4 photosynthesis.
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Affiliation(s)
- Urte Schlüter
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich Heine University, 40225 Düsseldorf, Germany; ,
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40
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Ermakova M, Danila FR, Furbank RT, von Caemmerer S. On the road to C 4 rice: advances and perspectives. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:940-950. [PMID: 31596523 PMCID: PMC7065233 DOI: 10.1111/tpj.14562] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 09/27/2019] [Accepted: 10/03/2019] [Indexed: 05/18/2023]
Abstract
The international C4 rice consortium aims to introduce into rice a high capacity photosynthetic mechanism, the C4 pathway, to increase yield. The C4 pathway is characterised by a complex combination of biochemical and anatomical specialisation that ensures high CO2 partial pressure at RuBisCO sites in bundle sheath (BS) cells. Here we report an update of the progress of the C4 rice project. Since its inception in 2008 there has been an exponential growth in synthetic biology and molecular tools. Golden Gate cloning and synthetic promoter systems have facilitated gene building block approaches allowing multiple enzymes and metabolite transporters to be assembled and expressed from single gene constructs. Photosynthetic functionalisation of the BS in rice remains an important step and there has been some success overexpressing transcription factors in the cytokinin signalling network which influence chloroplast volume. The C4 rice project has rejuvenated the research interest in C4 photosynthesis. Comparative anatomical studies now point to critical features essential for the design. So far little attention has been paid to the energetics. C4 photosynthesis has a greater ATP requirement, which is met by increased cyclic electron transport in BS cells. We hypothesise that changes in energy statues may drive this increased capacity for cyclic electron flow without the need for further modification. Although increasing vein density will ultimately be necessary for high efficiency C4 rice, our modelling shows that small amounts of C4 photosynthesis introduced around existing veins could already provide benefits of increased photosynthesis on the road to C4 rice.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Florence R. Danila
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
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Khoshravesh R, Stata M, Busch FA, Saladié M, Castelli JM, Dakin N, Hattersley PW, Macfarlane TD, Sage RF, Ludwig M, Sage TL. The Evolutionary Origin of C 4 Photosynthesis in the Grass Subtribe Neurachninae. PLANT PHYSIOLOGY 2020; 182:566-583. [PMID: 31611421 PMCID: PMC6945869 DOI: 10.1104/pp.19.00925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 05/10/2023]
Abstract
The Australian grass subtribe Neurachninae contains closely related species that use C3, C4, and C2 photosynthesis. To gain insight into the evolution of C4 photosynthesis in grasses, we examined leaf gas exchange, anatomy and ultrastructure, and tissue localization of Gly decarboxylase subunit P (GLDP) in nine Neurachninae species. We identified previously unrecognized variation in leaf structure and physiology within Neurachne that represents varying degrees of C3-C4 intermediacy in the Neurachninae. These include inverse correlations between the apparent photosynthetic carbon dioxide (CO2) compensation point in the absence of day respiration (C * ) and chloroplast and mitochondrial investment in the mestome sheath (MS), where CO2 is concentrated in C2 and C4 Neurachne species; width of the MS cells; frequency of plasmodesmata in the MS cell walls adjoining the parenchymatous bundle sheath; and the proportion of leaf GLDP invested in the MS tissue. Less than 12% of the leaf GLDP was allocated to the MS of completely C3 Neurachninae species with C * values of 56-61 μmol mol-1, whereas two-thirds of leaf GLDP was in the MS of Neurachne lanigera, which exhibits a newly-identified, partial C2 phenotype with C * of 44 μmol mol-1 Increased investment of GLDP in MS tissue of the C2 species was attributed to more MS mitochondria and less GLDP in mesophyll mitochondria. These results are consistent with a model where C4 evolution in Neurachninae initially occurred via an increase in organelle and GLDP content in MS cells, which generated a sink for photorespired CO2 in MS tissues.
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Affiliation(s)
- Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Matt Stata
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Florian A Busch
- Research School of Biology and Australian Research Council Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Montserrat Saladié
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Joanne M Castelli
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Nicole Dakin
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Paul W Hattersley
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Terry D Macfarlane
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
- Western Australian Herbarium, Department of Biodiversity, Conservation and Attractions, Perth, Western Australia 6983 Australia
| | - Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Martha Ludwig
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada, M5S 3B2
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42
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Mai KKK, Gao P, Kang BH. Electron Microscopy Views of Dimorphic Chloroplasts in C4 Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:1020. [PMID: 32719711 PMCID: PMC7350421 DOI: 10.3389/fpls.2020.01020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/22/2020] [Indexed: 05/02/2023]
Abstract
C4 plants enhance photosynthesis efficiency by concentrating CO2 to the site of Rubisco action. Chloroplasts in C4 plants exhibit structural dimorphism because thylakoid architectures vary depending on energy requirements. Advances in electron microscopy imaging capacity and sample preparation technologies allowed characterization of thylakoid structures and their macromolecular arrangements with unprecedented precision mostly in C3 plants. The thylakoid is assembled during chloroplast biogenesis through collaboration between the plastid and nuclear genomes. Recently, the membrane dynamics involved in the assembly process has been investigated with 3D electron microscopy, and molecular factors required for thylakoid construction have been characterized. The two classes of chloroplasts in C4 plants arise from common precursors, but little is known about how a single type of chloroplasts grow, divide, and differentiate to mature into distinct chloroplasts. Here, we outline the thylakoid structure and its assembly processes in C3 plants to discuss ultrastructural analyses of dimorphic chloroplast biogenesis in C4 plant species. Future directions for electron microscopy research of C4 photosynthetic systems are also proposed.
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43
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Deinum EE, Mulder BM, Benitez-Alfonso Y. From plasmodesma geometry to effective symplasmic permeability through biophysical modelling. eLife 2019; 8:49000. [PMID: 31755863 PMCID: PMC6994222 DOI: 10.7554/elife.49000] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/16/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of molecular transport via intercellular channels called plasmodesmata (PDs) is important for both coordinating developmental and environmental responses among neighbouring cells, and isolating (groups of) cells to execute distinct programs. Cell-to-cell mobility of fluorescent molecules and PD dimensions (measured from electron micrographs) are both used as methods to predict PD transport capacity (i.e., effective symplasmic permeability), but often yield very different values. Here, we build a theoretical bridge between both experimental approaches by calculating the effective symplasmic permeability from a geometrical description of individual PDs and considering the flow towards them. We find that a dilated central region has the strongest impact in thick cell walls and that clustering of PDs into pit fields strongly reduces predicted permeabilities. Moreover, our open source multi-level model allows to predict PD dimensions matching measured permeabilities and add a functional interpretation to structural differences observed between PDs in different cell walls.
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Affiliation(s)
- Eva E Deinum
- Mathematical and statistical methods (Biometris), Wageningen University, Wageningen, Netherlands
| | - Bela M Mulder
- Living Matter Department, Institute AMOLF, Amsterdam, Netherlands.,Laboratory of Cell Biology, Wageningen University, Wageningen, Netherlands
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44
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Dehigaspitiya P, Milham P, Ash GJ, Arun-Chinnappa K, Gamage D, Martin A, Nagasaka S, Seneweera S. Exploring natural variation of photosynthesis in a site-specific manner: evolution, progress, and prospects. PLANTA 2019; 250:1033-1050. [PMID: 31254100 DOI: 10.1007/s00425-019-03223-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 06/20/2019] [Indexed: 06/09/2023]
Abstract
Site-specific changes of photosynthesis, a relatively new concept, can be used to improve the productivity of critical food crops to mitigate the foreseen food crisis. Global food security is threatened by an increasing population and the effects of climate change. Large yield improvements were achieved in major cereal crops between the 1950s and 1980s through the Green Revolution. However, we are currently experiencing a significant decline in yield progress. Of the many approaches to improved cereal yields, exploitation of the mode of photosynthesis has been intensely studied. Even though the C4 pathway is considered the most efficient, mainly because of the carbon concentrating mechanisms around the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase, which minimize photorespiration, much is still unknown about the specific gene regulation of this mode of photosynthesis. Most of the critical cereal crops, including wheat and rice, are categorized as C3 plants based on the photosynthesis of major photosynthetic organs. However, recent findings raise the possibility of different modes of photosynthesis occurring at different sites in the same plant and/or in plants grown in different habitats. That is, it seems possible that efficient photosynthetic traits may be expressed in specific organs, even though the major photosynthetic pathway is C3. Knowledge of site-specific differences in photosynthesis, coupled with site-specific regulation of gene expression, may therefore hold a potential to enhance the yields of economically important C3 crops.
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Affiliation(s)
| | - Paul Milham
- Hawkesbury Institute for the Environment, Western Sydney University, LB 1797, Penrith, NSW, 2753, Australia
| | - Gavin J Ash
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia
| | - Kiruba Arun-Chinnappa
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia
| | - Dananjali Gamage
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia
| | - Anke Martin
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia
| | - Seiji Nagasaka
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia
| | - Saman Seneweera
- Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD, 4350, Australia.
- National Institute of Fundamental Studies, Hanthana Road, Kandy, 20000, Central, Sri Lanka.
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45
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Danila FR, Quick WP, White RG, von Caemmerer S, Furbank RT. Response of plasmodesmata formation in leaves of C 4 grasses to growth irradiance. PLANT, CELL & ENVIRONMENT 2019; 42:2482-2494. [PMID: 30965390 DOI: 10.1111/pce.13558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Rapid metabolite diffusion across the mesophyll (M) and bundle sheath (BS) cell interface in C4 leaves is a key requirement for C4 photosynthesis and occurs via plasmodesmata (PD). Here, we investigated how growth irradiance affects PD density between M and BS cells and between M cells in two C4 species using our PD quantification method, which combines three-dimensional laser confocal fluorescence microscopy and scanning electron microscopy. The response of leaf anatomy and physiology of NADP-ME species, Setaria viridis and Zea mays to growth under different irradiances, low light (100 μmol m-2 s-1 ), and high light (1,000 μmol m-2 s-1 ), was observed both at seedling and established growth stages. We found that the effect of growth irradiance on C4 leaf PD density depended on plant age and species. The high light treatment resulted in two to four-fold greater PD density per unit leaf area than at low light, due to greater area of PD clusters and greater PD size in high light plants. These results along with our finding that the effect of light on M-BS PD density was not tightly linked to photosynthetic capacity suggest a complex mechanism underlying the dynamic response of C4 leaf PD formation to growth irradiance.
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Affiliation(s)
- Florence R Danila
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - William Paul Quick
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- International Rice Research Institute, Los Baños, Laguna, 4030, Philippines
- University of Sheffield, Sheffield, UK
| | - Rosemary G White
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia
| | - Susanne von Caemmerer
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Robert T Furbank
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia
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46
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Bellasio C, Farquhar GD. A leaf-level biochemical model simulating the introduction of C 2 and C 4 photosynthesis in C 3 rice: gains, losses and metabolite fluxes. THE NEW PHYTOLOGIST 2019; 223:150-166. [PMID: 30859576 DOI: 10.1111/nph.15787] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/03/2019] [Indexed: 05/21/2023]
Abstract
This work aims at developing an adequate theoretical basis for comparing assimilation of the ancestral C3 pathway with CO2 concentrating mechanisms (CCM) that have evolved to reduce photorespiratory yield losses. We present a novel model for C3 , C2 , C2 + C4 and C4 photosynthesis simulating assimilatory metabolism, energetics and metabolite traffic at the leaf level. It integrates a mechanistic description of light reactions to simulate ATP and NADPH production, and a variable engagement of cyclic electron flow. The analytical solutions are compact and thus suitable for larger scale simulations. Inputs were derived with a comprehensive gas-exchange experiment. We show trade-offs in the operation of C4 that are in line with ecophysiological data. C4 has the potential to increase assimilation over C3 at high temperatures and light intensities, but this benefit is reversed under low temperatures and light. We apply the model to simulate the introduction of progressively complex levels of CCM into C3 rice, which feeds > 3.5 billion people. Increasing assimilation will require considerable modifications such as expressing the NAD(P)H Dehydrogenase-like complex and upregulating cyclic electron flow, enlarging the bundle sheath, and expressing suitable transporters to allow adequate metabolite traffic. The simpler C2 rice may be a desirable alternative.
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Affiliation(s)
- Chandra Bellasio
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
- University of the Balearic Islands, Palma, Illes Balears, 07122, Spain
- Trees and Timber Institute, National Research Council of Italy, Sesto Fiorentino, Florence, 50019, Italy
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
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47
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Niklaus M, Kelly S. The molecular evolution of C4 photosynthesis: opportunities for understanding and improving the world's most productive plants. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:795-804. [PMID: 30462241 DOI: 10.1093/jxb/ery416] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 11/09/2018] [Indexed: 05/28/2023]
Abstract
C4 photosynthesis is a convergent evolutionary trait that enhances photosynthetic efficiency in a variety of environmental conditions. It has evolved repeatedly following a fall in atmospheric CO2 concentration such that there is up to a 30 million year difference in the amount of time that natural selection has had to improve C4 function between the oldest and youngest C4 lineages. This large difference in time, coupled with the phylogenetic distance between lineages, has resulted in a large disparity in anatomy, physiology, and biochemistry between extant C4 species. This review summarizes the myriad of molecular sequence changes that have been linked to the evolution of C4 photosynthesis. These range from single nucleotide changes to duplication of entire genes, and provide a roadmap for how natural selection has adapted enzymes and pathways for enhanced C4 function. Finally, this review discusses how this molecular diversity can provide opportunities for understanding and improving photosynthesis for multiple important C4 food, feed, and bioenergy crops.
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Affiliation(s)
- Michael Niklaus
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, Oxford, UK
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48
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Alonso-Cantabrana H, Cousins AB, Danila F, Ryan T, Sharwood RE, von Caemmerer S, Furbank RT. Diffusion of CO 2 across the Mesophyll-Bundle Sheath Cell Interface in a C 4 Plant with Genetically Reduced PEP Carboxylase Activity. PLANT PHYSIOLOGY 2018; 178:72-81. [PMID: 30018172 PMCID: PMC6130029 DOI: 10.1104/pp.18.00618] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/10/2018] [Indexed: 05/22/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC), localized to the cytosol of the mesophyll cell, catalyzes the first carboxylation step of the C4 photosynthetic pathway. Here, we used RNA interference to target the cytosolic photosynthetic PEPC isoform in Setaria viridis and isolated independent transformants with very low PEPC activities. These plants required high ambient CO2 concentrations for growth, consistent with the essential role of PEPC in C4 photosynthesis. The combination of estimating direct CO2 fixation by the bundle sheath using gas-exchange measurements and modeling C4 photosynthesis with low PEPC activity allowed the calculation of bundle sheath conductance to CO2 diffusion (gbs ) in the progeny of these plants. Measurements made at a range of temperatures suggested no or negligible effect of temperature on gbs depending on the technique used to calculate gbs Anatomical measurements revealed that plants with reduced PEPC activity had reduced cell wall thickness and increased plasmodesmata (PD) density at the mesophyll-bundle sheath (M-BS) cell interface, whereas we observed little difference in these parameters at the mesophyll-mesophyll cell interface. The increased PD density at the M-BS interface was largely driven by an increase in the number of PD pit fields (cluster of PDs) rather than an increase in PD per pit field or the size of pit fields. The correlation of gbs with bundle sheath surface area per leaf area and PD area per M-BS area showed that these parameters and cell wall thickness are important determinants of gbs It is intriguing to speculate that PD development is responsive to changes in C4 photosynthetic flux.
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Affiliation(s)
- Hugo Alonso-Cantabrana
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164-4236
| | - Florence Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Timothy Ryan
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Robert E Sharwood
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
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Creating Leaf Cell Suspensions for Characterization of Mesophyll and Bundle Sheath Cellular Features. Methods Mol Biol 2018. [PMID: 29978407 DOI: 10.1007/978-1-4939-7786-4_15] [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
Imaging of mesophyll cell suspensions prepared from Arabidopsis has been pivotal for forming our current understanding of the molecular control of chloroplast division over the past 25 years. In this chapter, we provide a method for the preparation of leaf cell suspensions that improves upon a previous method by optimizing cellular preservation and cell separation. This technique is accessible to all researchers and amenable for use with all plant species. The leaf suspensions can be used for imaging chloroplast features within a cell that are important for photosynthesis such as size, number, and distribution. However, we also provide examples to illustrate how the cells in the suspensions can be easily stained to image other features, for example pit fields where plasmodesmata are located and organelles such as mitochondria, to improve our understanding of traits that are important for photosynthetic physiology.
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Lu KJ, Danila FR, Cho Y, Faulkner C. Peeking at a plant through the holes in the wall - exploring the roles of plasmodesmata. THE NEW PHYTOLOGIST 2018; 218:1310-1314. [PMID: 29574753 DOI: 10.1111/nph.15130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Plasmodesmata (PD) are membrane-lined pores that connect neighbouring plant cells and allow molecular exchange via the symplast. Past studies have revealed the basic structure of PD, some of the transport mechanisms for molecules through PD, and a variety of physiological processes in which they function. Recently, with the help of newly developed technologies, several exciting new features of PD have been revealed. New PD structures were observed during early formation of PD and between phloem sieve elements and phloem pole pericycle cells in roots. Both observations challenge our current understanding of PD structure and function. Research into novel physiological responses, which are regulated by PD, indicates that we have not yet fully explored the potential contribution of PD to overall plant function. In this Viewpoint article, we summarize some of the recent advances in understanding the structure and function of PD and propose the challenges ahead for the community.
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Affiliation(s)
- Kuan-Ju Lu
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE, Wageningen, the Netherlands
| | - Florence R Danila
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Yueh Cho
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Programme, National Chung Hsing University and Academia Sinica, Taipei, 11529, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
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