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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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Guerreiro R, Bonthala VS, Schlüter U, Hoang NV, Triesch S, Schranz ME, Weber APM, Stich B. A genomic panel for studying C3-C4 intermediate photosynthesis in the Brassiceae tribe. PLANT, CELL & ENVIRONMENT 2023; 46:3611-3627. [PMID: 37431820 DOI: 10.1111/pce.14662] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 05/18/2023] [Accepted: 06/23/2023] [Indexed: 07/12/2023]
Abstract
Research on C4 and C3-C4 photosynthesis has attracted significant attention because the understanding of the genetic underpinnings of these traits will support the introduction of its characteristics into commercially relevant crop species. We used a panel of 19 taxa of 18 Brassiceae species with different photosynthesis characteristics (C3 and C3-C4) with the following objectives: (i) create draft genome assemblies and annotations, (ii) quantify orthology levels using synteny maps between all pairs of taxa, (iii) describe the phylogenetic relatedness across all the species, and (iv) track the evolution of C3-C4 intermediate photosynthesis in the Brassiceae tribe. Our results indicate that the draft de novo genome assemblies are of high quality and cover at least 90% of the gene space. Therewith we more than doubled the sampling depth of genomes of the Brassiceae tribe that comprises commercially important as well as biologically interesting species. The gene annotation generated high-quality gene models, and for most genes extensive upstream sequences are available for all taxa, yielding potential to explore variants in regulatory sequences. The genome-based phylogenetic tree of the Brassiceae contained two main clades and indicated that the C3-C4 intermediate photosynthesis has evolved five times independently. Furthermore, our study provides the first genomic support of the hypothesis that Diplotaxis muralis is a natural hybrid of D. tenuifolia and D. viminea. Altogether, the de novo genome assemblies and the annotations reported in this study are a valuable resource for research on the evolution of C3-C4 intermediate photosynthesis.
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Affiliation(s)
- Ricardo Guerreiro
- Institute of Quantitative Genetics and Genomics of Plants, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Venkata Suresh Bonthala
- Institute of Quantitative Genetics and Genomics of Plants, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
| | - Urte Schlüter
- Institute of Plant Biochemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Düsseldorf, Germany
| | - Nam V Hoang
- Biosystematics Group, Department of Plant Sciences, Wageningen University, Wageningen, The Netherlands
| | - Sebastian Triesch
- Institute of Plant Biochemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Düsseldorf, Germany
| | - M Eric Schranz
- Biosystematics Group, Department of Plant Sciences, Wageningen University, Wageningen, The Netherlands
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Düsseldorf, Germany
| | - Benjamin Stich
- Institute of Quantitative Genetics and Genomics of Plants, Faculty of Mathematics and Natural Sciences, Heinrich Heine University, Düsseldorf, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), Düsseldorf, Germany
- Max Planck Institute for Plant Breeding Research, Köln, Germany
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3
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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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4
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Rojas BE, Tonetti T, Figueroa CM. Trehalose 6-phosphate metabolism in C 4 species. CURRENT OPINION IN PLANT BIOLOGY 2023; 72:102347. [PMID: 36806837 DOI: 10.1016/j.pbi.2023.102347] [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: 11/01/2022] [Revised: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, is an essential signal metabolite in plants, linking growth and development to carbon status. Our current understanding of Tre6P metabolism and signaling pathways in plants is based almost entirely on studies performed with Arabidopsis thaliana, a model plant that performs C3 photosynthesis. Conversely, our knowledge on the molecular mechanisms involved in Tre6P regulation of carbon partitioning and metabolism in C4 plants is scarce. This topic is especially relevant due to the agronomic importance of crops performing C4 photosynthesis, such as maize, sorghum and sugarcane. In this review, we focused our attention on recent developments related to Tre6P metabolism in C4 species and raised some open questions that should be addressed in the near future to improve the yield of economically important crops.
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Affiliation(s)
- Bruno E Rojas
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Tomás Tonetti
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina.
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5
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Cui X, Jun JH, Rao X, Bahr C, Chapman E, Temple S, Dixon RA. Leaf layer-based transcriptome profiling for discovery of epidermal-selective promoters in Medicago truncatula. PLANTA 2022; 256:31. [PMID: 35790623 DOI: 10.1007/s00425-022-03920-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
Transcriptomics of manually dissected leaf layers from Medicago truncatula identifies genes with preferential expression in upper and/or lower epidermis. The promoters of these genes confer epidermal-specific expression of transgenes. Improving the quality and quantity of proanthocyanidins (PAs) in forage legumes has potential to improve the nitrogen nutrition of ruminant animals and protect them from the risk of pasture bloat, as well as parasites. However, ectopic constitutive accumulation of PAs in plants by genetic engineering can significantly inhibit growth. We selected the leaf epidermis as a candidate tissue for targeted engineering of PAs or other pathways. To identify gene promoters selectively expressed in epidermal tissues, we performed comparative transcriptomic analyses in the model legume Medicago truncatula, using five tissue samples representing upper epidermis, lower epidermis, whole leaf without upper epidermis, whole leaf without lower epidermis, and whole leaf. We identified 52 transcripts preferentially expressed in upper epidermis, most of which encode genes involved in flavonoid biosynthesis, and 53 transcripts from lower epidermis, with the most enriched category being anatomical structure formation. Promoters of the preferentially expressed genes were cloned from the M. truncatula genome and shown to direct tissue-selective promoter activities in transient assays. Expression of the PA pathway transcription factor TaMYB14 under control of several of the promoters in transgenic alfalfa resulted in only modest MYB14 transcript accumulation and low levels of PA production. Activity of a subset of promoters was confirmed by transcript analysis in field-grown alfalfa plants throughout the growing season, and revealed variable but consistent expression, which was generally highest 3-4 weeks after cutting. We conclude that, although the selected promoters show acceptable tissue-specificity, they may not drive high enough transcription factor expression to activate the PA pathway.
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Affiliation(s)
- Xin Cui
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
| | - Ji Hyung Jun
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
- Children's Research Institute and the Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiaolan Rao
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA
- College of Life Sciences, Hubei University, Wuhan, 430068, Hubei, China
| | - Camille Bahr
- Forage Genetics International, N5292 Gills Coulee Rd S, West Salem, WI, 54669, USA
| | - Elisabeth Chapman
- Forage Genetics International, N5292 Gills Coulee Rd S, West Salem, WI, 54669, USA
| | - Stephen Temple
- Forage Genetics International, N5292 Gills Coulee Rd S, West Salem, WI, 54669, USA
| | - Richard A Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, 1155 Union Circle #311428, Denton, TX, 76203, USA.
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Single-Cell Transcriptome and Network Analyses Unveil Key Transcription Factors Regulating Mesophyll Cell Development in Maize. Genes (Basel) 2022; 13:genes13020374. [PMID: 35205426 PMCID: PMC8872562 DOI: 10.3390/genes13020374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 12/17/2022] Open
Abstract
Background: Maize mesophyll (M) cells play important roles in various biological processes such as photosynthesis II and secondary metabolism. Functional differentiation occurs during M-cell development, but the underlying mechanisms for regulating M-cell development are largely unknown. Results: We conducted single-cell RNA sequencing (scRNA-seq) to profile transcripts in maize leaves. We then identified coregulated modules by analyzing the resulting pseudo-time-series data through gene regulatory network analyses. WRKY, ERF, NAC, MYB and Heat stress transcription factor (HSF) families were highly expressed in the early stage, whereas CONSTANS (CO)-like (COL) and ERF families were highly expressed in the late stage of M-cell development. Construction of regulatory networks revealed that these transcript factor (TF) families, especially HSF and COL, were the major players in the early and later stages of M-cell development, respectively. Integration of scRNA expression matrix with TF ChIP-seq and Hi-C further revealed regulatory interactions between these TFs and their targets. HSF1 and COL8 were primarily expressed in the leaf bases and tips, respectively, and their targets were validated with protoplast-based ChIP-qPCR, with the binding sites of HSF1 being experimentally confirmed. Conclusions: Our study provides evidence that several TF families, with the involvement of epigenetic regulation, play vital roles in the regulation of M-cell development in maize.
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7
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Chotewutmontri P, Barkan A. Ribosome profiling elucidates differential gene expression in bundle sheath and mesophyll cells in maize. PLANT PHYSIOLOGY 2021; 187:59-72. [PMID: 34618144 PMCID: PMC8418429 DOI: 10.1093/plphys/kiab272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/10/2021] [Indexed: 05/20/2023]
Abstract
The efficiencies offered by C4 photosynthesis have motivated efforts to understand its biochemical, genetic, and developmental basis. Reactions underlying C4 traits in most C4 plants are partitioned between two cell types, bundle sheath (BS), and mesophyll (M) cells. RNA-seq has been used to catalog differential gene expression in BS and M cells in maize (Zea mays) and several other C4 species. However, the contribution of translational control to maintaining the distinct proteomes of BS and M cells has not been addressed. In this study, we used ribosome profiling and RNA-seq to describe translatomes, translational efficiencies, and microRNA abundance in BS- and M-enriched fractions of maize seedling leaves. A conservative interpretation of our data revealed 182 genes exhibiting cell type-dependent differences in translational efficiency, 31 of which encode proteins with core roles in C4 photosynthesis. Our results suggest that non-AUG start codons are used preferentially in upstream open reading frames of BS cells, revealed mRNA sequence motifs that correlate with cell type-dependent translation, and identified potential translational regulators that are differentially expressed. In addition, our data expand the set of genes known to be differentially expressed in BS and M cells, including genes encoding transcription factors and microRNAs. These data add to the resources for understanding the evolutionary and developmental basis of C4 photosynthesis and for its engineering into C3 crops.
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Affiliation(s)
- Prakitchai Chotewutmontri
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 USA
- Author for communication:
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 USA
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8
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Furbank RT, Kelly S. Finding the C4 sweet spot: cellular compartmentation of carbohydrate metabolism in C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6018-6026. [PMID: 34142128 PMCID: PMC8411606 DOI: 10.1093/jxb/erab290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/14/2021] [Indexed: 05/10/2023]
Abstract
The two-cell type C4 photosynthetic pathway requires both anatomical and biochemical specialization to achieve a functional CO2-concentrating mechanism. While a great deal of research has been done on Kranz anatomy and cell-specific expression and activity of enzymes in the C4 pathway, less attention has been paid to partitioning of carbohydrate synthesis between the cell types of C4 leaves. As early as the 1970s it became apparent that, in the small number of species examined at the time, sucrose was predominantly synthesized in the mesophyll cells and starch in the bundle sheath cells. Here we discuss how this partitioning is achieved in C4 plants and explore whether this is a consequence of C4 metabolism or indeed a requirement for its evolution and efficient operation.
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Affiliation(s)
- Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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9
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Furbank RT, Kelly S. Finding the C4 sweet spot: cellular compartmentation of carbohydrate metabolism in C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2021. [PMID: 34142128 DOI: 10.5061/dryad.cz8w9gj3v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The two-cell type C4 photosynthetic pathway requires both anatomical and biochemical specialization to achieve a functional CO2-concentrating mechanism. While a great deal of research has been done on Kranz anatomy and cell-specific expression and activity of enzymes in the C4 pathway, less attention has been paid to partitioning of carbohydrate synthesis between the cell types of C4 leaves. As early as the 1970s it became apparent that, in the small number of species examined at the time, sucrose was predominantly synthesized in the mesophyll cells and starch in the bundle sheath cells. Here we discuss how this partitioning is achieved in C4 plants and explore whether this is a consequence of C4 metabolism or indeed a requirement for its evolution and efficient operation.
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Affiliation(s)
- Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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10
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Bezrutczyk M, Zöllner NR, Kruse CPS, Hartwig T, Lautwein T, Köhrer K, Frommer WB, Kim JY. Evidence for phloem loading via the abaxial bundle sheath cells in maize leaves. THE PLANT CELL 2021; 33:531-547. [PMID: 33955497 PMCID: PMC8136869 DOI: 10.1093/plcell/koaa055] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/01/2020] [Indexed: 05/22/2023]
Abstract
Leaves are asymmetric, with different functions for adaxial and abaxial tissue. The bundle sheath (BS) of C3 barley (Hordeum vulgare) is dorsoventrally differentiated into three types of cells: adaxial structural, lateral S-type, and abaxial L-type BS cells. Based on plasmodesmatal connections between S-type cells and mestome sheath (parenchymatous cell layer below bundle sheath), S-type cells likely transfer assimilates toward the phloem. Here, we used single-cell RNA sequencing to investigate BS differentiation in C4 maize (Zea mays L.) plants. Abaxial BS (abBS) cells of rank-2 intermediate veins specifically expressed three SWEET sucrose uniporters (SWEET13a, b, and c) and UmamiT amino acid efflux transporters. SWEET13a, b, c mRNAs were also detected in the phloem parenchyma (PP). We show that maize has acquired a mechanism for phloem loading in which abBS cells provide the main route for apoplasmic sucrose transfer toward the phloem. This putative route predominates in veins responsible for phloem loading (rank-2 intermediate), whereas rank-1 intermediate and major veins export sucrose from the PP adjacent to the sieve element companion cell complex, as in Arabidopsis thaliana. We surmise that abBS identity is subject to dorsoventral patterning and has components of PP identity. These observations provide insights into the unique transport-specific properties of abBS cells and support a modification to the canonical phloem loading pathway in maize.
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Affiliation(s)
- Margaret Bezrutczyk
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Nora R Zöllner
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Colin P S Kruse
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Thomas Hartwig
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
| | - Tobias Lautwein
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany
| | - Karl Köhrer
- Biological and Medical Research Center (BMFZ), Genomics and Transcriptomics Laboratory (GTL), Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany
| | - Wolf B Frommer
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
- Author for correspondence:
| | - Ji-Yun Kim
- Institute for Molecular Physiology, Heinrich-Heine-University Düsseldorf, Düsseldorf 40225, Germany
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11
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Jobe TO, Rahimzadeh Karvansara P, Zenzen I, Kopriva S. Ensuring Nutritious Food Under Elevated CO 2 Conditions: A Case for Improved C 4 Crops. FRONTIERS IN PLANT SCIENCE 2020; 11:1267. [PMID: 33013946 PMCID: PMC7461923 DOI: 10.3389/fpls.2020.01267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/03/2020] [Indexed: 05/04/2023]
Abstract
Global climate change is a challenge for efforts to ensure food security for future generations. It will affect crop yields through changes in temperature and precipitation, as well as the nutritional quality of crops. Increased atmospheric CO2 leads to a penalty in the content of proteins and micronutrients in most staple crops, with the possible exception of C4 crops. It is essential to understand the control of nutrient homeostasis to mitigate this penalty. However, despite the importance of mineral nutrition for plant performance, comparably less is known about the regulation of nutrient uptake and homeostasis in C4 plants than in C3 plants and mineral nutrition has not been a strong focus of the C4 research. Here we review what is known about C4 specific features of nitrogen and sulfur assimilation as well as of homeostasis of other essential elements. We identify the major knowledge gaps and urgent questions for future research. We argue that adaptations in mineral nutrition were an integral part of the evolution of C4 photosynthesis and should be considered in the attempts to engineer C4 photosynthetic mechanisms into C3 crops.
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Affiliation(s)
- Timothy O Jobe
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Parisa Rahimzadeh Karvansara
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Ivan Zenzen
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
| | - Stanislav Kopriva
- Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany
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12
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Lyu MJA, Wang Y, Jiang J, Liu X, Chen G, Zhu XG. What Matters for C 4 Transporters: Evolutionary Changes of Phospho enolpyruvate Transporter for C 4 Photosynthesis. FRONTIERS IN PLANT SCIENCE 2020; 11:935. [PMID: 32695130 PMCID: PMC7338763 DOI: 10.3389/fpls.2020.00935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Abstract
C4 photosynthesis is a complex trait that evolved from its ancestral C3 photosynthesis by recruiting pre-existing genes. These co-opted genes were changed in many aspects compared to their counterparts in C3 species. Most of the evolutionary changes of the C4 shuttle enzymes are well characterized, however, evolutionary changes for the recruited metabolite transporters are less studied. Here we analyzed the evolutionary changes of the shuttle enzyme phosphoenolpyruvate (PEP) transporter (PPT) during its recruitment from C3 to C4 photosynthesis. Our analysis showed that among the two PPT paralogs PPT1 and PPT2, PPT1 was the copy recruited for C4 photosynthesis in multiple C4 lineages. During C4 evolution, PPT1 gained increased transcript abundance, shifted its expression from predominantly in root to in leaf and from bundle sheath cell to mesophyll cell, and gained more rapid and long-lasting responsiveness to light. Modifications occurred in both regulatory and coding regions in C4 PPT1 as compared to C3 PPT1, however, the PEP transporting function of PPT1 remained. We found that PPT1 of a Flaveria C4 species recruited a MEM1 B submodule in the promoter region, which might be related to the increased transcript abundance of PPT1 in C4 mesophyll cells. The case study of PPT further suggested that high transcript abundance in a proper location is of high priority for PPT to support C4 function.
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Affiliation(s)
- Ming-Ju Amy Lyu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence In Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yaling Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence In Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Jianjun Jiang
- Wisconsin Institute for Discovery & Laboratory of Genetics, University of Wisconsin, Madison, WI, United States
| | - Xinyu Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence In Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Genyun Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence In Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xin-Guang Zhu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence In Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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13
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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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14
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Hughes TE, Sedelnikova OV, Wu H, Becraft PW, Langdale JA. Redundant SCARECROW genes pattern distinct cell layers in roots and leaves of maize. Development 2019; 146:dev.177543. [PMID: 31235633 PMCID: PMC6679360 DOI: 10.1242/dev.177543] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/13/2019] [Indexed: 01/29/2023]
Abstract
The highly efficient C4 photosynthetic pathway is facilitated by ‘Kranz’ leaf anatomy. In Kranz leaves, closely spaced veins are encircled by concentric layers of photosynthetic bundle sheath (inner) and mesophyll (outer) cells. Here, we demonstrate that, in the C4 monocot maize, Kranz patterning is regulated by redundant function of SCARECROW 1 (ZmSCR1) and a previously uncharacterized homeologue: ZmSCR1h. ZmSCR1 and ZmSCR1h transcripts accumulate in ground meristem cells of developing leaf primordia and in Zmscr1;Zmscr1h mutant leaves, most veins are separated by one rather than two mesophyll cells; many veins have sclerenchyma above and/or below instead of mesophyll cells; and supernumerary bundle sheath cells develop. The mutant defects are unified by compromised mesophyll cell development. In addition to Kranz defects, Zmscr1;Zmscr1h mutants fail to form an organized endodermal layer in the root. Collectively, these data indicate that ZmSCR1 and ZmSCR1h redundantly regulate cell-type patterning in both the leaves and roots of maize. Leaf and root pathways are distinguished, however, by the cell layer in which they operate – mesophyll at a two-cell distance from leaf veins versus endodermis immediately adjacent to root vasculature. Summary: Two duplicated maize SCARECROW genes control the development of the endodermis in roots and the mesophyll in leaves.
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Affiliation(s)
- Thomas E Hughes
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Olga V Sedelnikova
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Hao Wu
- Genetics, Development, and Cell Biology Department, Iowa State University, Ames, IA 50011, USA
| | - Philip W Becraft
- Genetics, Development, and Cell Biology Department, Iowa State University, Ames, IA 50011, USA
| | - Jane A Langdale
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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15
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Schlüter U, Bräutigam A, Droz JM, Schwender J, Weber APM. The role of alanine and aspartate aminotransferases in C 4 photosynthesis. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21 Suppl 1:64-76. [PMID: 30126035 DOI: 10.1111/plb.12904] [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: 04/03/2018] [Accepted: 08/15/2018] [Indexed: 06/08/2023]
Abstract
Alanine and aspartate are essential transfer metabolites for C4 species of the NAD-malic enzyme and phosphoenolpyruvate carboxykinase subtype. To some degree both amino acids are also part of the metabolite shuttle in NADP-malic enzyme plants. In comparison with C3 species, the majority of C4 species are therefore characterised by enhanced expression and activity of alanine and aspartate aminotransferases (AT) in the photosynthetically active tissue. Both enzymes exist in multiple copies and have been found in different subcellular compartments. We tested whether different C4 species show preferential recruitment of enzymes from specific lineages and subcellular compartments. Phylogenetic analysis of alanine and aspartate ATs from a variety of monocot and eudicot C4 species and their C3 relatives was combined with subcellular prediction tools and analysis of the subsequent transcript amounts in mature leaves. Recruitment of aspartate AT from a specific subcellular compartment was strongly connected to the biochemical subtype. Deviation from the main model was however observed in Gynandropsis gynandra. The configuration of alanine AT generally differed in monocot and eudicot species. C4 monocots recruited an alanine AT from a specific cytosolic branch, but eudicots use alanine AT copies from a mitochondrial branch. Generally, plants display high plasticity in the setup of the C4 pathway. Beside the common models for the different C4 subtypes, individual solutions were found for plant groups or lineages.
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Affiliation(s)
- U Schlüter
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - A Bräutigam
- Computational Biology, Centre for Biotechnology, University Bielefeld, Bielefeld, Germany
| | | | - J Schwender
- Biology Department, Brookhaven National Laboratory, Upton, New York, USA
| | - A P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Science (CEPLAS), Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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16
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Bezrutczyk M, Hartwig T, Horschman M, Char SN, Yang J, Yang B, Frommer WB, Sosso D. Impaired phloem loading in zmsweet13a,b,c sucrose transporter triple knock-out mutants in Zea mays. THE NEW PHYTOLOGIST 2018; 218:594-603. [PMID: 29451311 DOI: 10.1111/nph.15021] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/28/2017] [Indexed: 05/02/2023]
Abstract
Crop yield depends on efficient allocation of sucrose from leaves to seeds. In Arabidopsis, phloem loading is mediated by a combination of SWEET sucrose effluxers and subsequent uptake by SUT1/SUC2 sucrose/H+ symporters. ZmSUT1 is essential for carbon allocation in maize, but the relative contribution to apoplasmic phloem loading and retrieval of sucrose leaking from the translocation path is not known. Here we analysed the contribution of SWEETs to phloem loading in maize. We identified three leaf-expressed SWEET sucrose transporters as key components of apoplasmic phloem loading in Zea mays L. ZmSWEET13 paralogues (a, b, c) are among the most highly expressed genes in the leaf vasculature. Genome-edited triple knock-out mutants were severely stunted. Photosynthesis of mutants was impaired and leaves accumulated high levels of soluble sugars and starch. RNA-seq revealed profound transcriptional deregulation of genes associated with photosynthesis and carbohydrate metabolism. Genome-wide association study (GWAS) analyses may indicate that variability in ZmSWEET13s correlates with agronomical traits, especifically flowering time and leaf angle. This work provides support for cooperation of three ZmSWEET13s with ZmSUT1 in phloem loading in Z. mays.
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Affiliation(s)
- Margaret Bezrutczyk
- Institute for Molecular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
- Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Department of Plant Biology, Carnegie Science, 260 Panama St, Stanford, CA, 94305, USA
| | - Thomas Hartwig
- Institute for Molecular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
- Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Department of Plant Biology, Carnegie Science, 260 Panama St, Stanford, CA, 94305, USA
| | - Marc Horschman
- Department of Plant Biology, Carnegie Science, 260 Panama St, Stanford, CA, 94305, USA
| | - Si Nian Char
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA
| | - Jinliang Yang
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Bing Yang
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, IA, 50011, USA
| | - Wolf B Frommer
- Institute for Molecular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
- Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany
- Department of Plant Biology, Carnegie Science, 260 Panama St, Stanford, CA, 94305, USA
| | - Davide Sosso
- Department of Plant Biology, Carnegie Science, 260 Panama St, Stanford, CA, 94305, USA
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17
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Chastain CJ, Baird LM, Walker MT, Bergman CC, Novbatova GT, Mamani-Quispe CS, Burnell JN. Maize leaf PPDK regulatory protein isoform-2 is specific to bundle sheath chloroplasts and paradoxically lacks a Pi-dependent PPDK activation activity. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1171-1181. [PMID: 29281064 PMCID: PMC6019023 DOI: 10.1093/jxb/erx471] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/04/2017] [Indexed: 05/18/2023]
Abstract
In C4 plants, the pyruvate phosphate dikinase regulatory protein (PDRP) regulates the C4 pathway enzyme pyruvate phosphate dikinase (PPDK) in response to changes in incident light intensity. In maize (Zea mays) leaves, two distinct isoforms of PDRP are expressed, ZmPDRP1 and ZmPDRP2. The properties and C4 function of the ZmPDRP1 isoform are well understood. However, the PDRP2 isoform has only recently been identified and its properties and function(s) in maize leaves are unknown. We therefore initiated an investigation into the maize PDRP2 isoform by performing a side by side comparison of its enzyme properties and cell-specific distribution with PDRP1. In terms of enzyme functionality, PDRP2 was found to possess the same protein kinase-specific activity as PDRP1. However, the PDRP2 isoform was found to lack the phosphotransferase activity of the bifunctional PDRP1 isoform except when PDRP2 in the assays is elevated 5- to 10-fold. A primarily immuno-based approach was used to show that PDRP1 is strictly expressed in mesophyll cells and PDRP2 is strictly expressed in bundle sheath strand cells (BSCs). Additionally, using in situ immunolocalization, we establish a regulatory target for PDRP2 by showing a significant presence of C4 PPDK in BSC chloroplasts. However, a metabolic role for PPDK in this compartment is obscure, assuming PPDK accumulating in this compartment would be irreversibly inactivated each dark cycle by a monofunctional PDRP2.
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Affiliation(s)
- Chris J Chastain
- Department of Biosciences, Minnesota State University-Moorhead, USA
- Correspondence:
| | - Lisa M Baird
- Department of Biology, University of San Diego, San Diego, CA, USA
| | | | | | | | | | - Jim N Burnell
- Department of Molecular and Cell Biology, James Cook University, Australia
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18
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von Caemmerer S, Ghannoum O, Furbank RT. C4 photosynthesis: 50 years of discovery and innovation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:97-102. [PMID: 28110274 PMCID: PMC5444450 DOI: 10.1093/jxb/erw491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
It is now over half a century since the biochemical characterization of the C4 photosynthetic pathway, and this special issue highlights the sheer breadth of current knowledge. New genomic and transcriptomic information shows that multi-level regulation of gene expression is required for the pathway to function, yet we know it to be one of the most dynamic examples of convergent evolution. Now, a focus on the molecular transition from C3-C4 intermediates, together with improved mathematical models, experimental tools and transformation systems, holds great promise for improving C4 photosynthesis in crops.
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Affiliation(s)
- 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 2601, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW 2753, Australia
| | - 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 2601, Australia
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