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Ma B, Zhang L, He Z. Understanding the regulation of cereal grain filling: The way forward. J Integr Plant Biol 2023; 65:526-547. [PMID: 36648157 DOI: 10.1111/jipb.13456] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/17/2023] [Indexed: 06/17/2023]
Abstract
During grain filling, starch and other nutrients accumulate in the endosperm; this directly determines grain yield and grain quality in crops such as rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum). Grain filling is a complex trait affected by both intrinsic and environmental factors, making it difficult to explore the underlying genetics, molecular regulation, and the application of these genes for breeding. With the development of powerful genetic and molecular techniques, much has been learned about the genes and molecular networks related to grain filling over the past decades. In this review, we highlight the key factors affecting grain filling, including both biological and abiotic factors. We then summarize the key genes controlling grain filling and their roles in this event, including regulators of sugar translocation and starch biosynthesis, phytohormone-related regulators, and other factors. Finally, we discuss how the current knowledge of valuable grain filling genes could be integrated with strategies for breeding cereal varieties with improved grain yield and quality.
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Affiliation(s)
- Bin Ma
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Lin Zhang
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zuhua He
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
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Gill RA, Ahmar S, Ali B, Saleem MH, Khan MU, Zhou W, Liu S. The Role of Membrane Transporters in Plant Growth and Development, and Abiotic Stress Tolerance. Int J Mol Sci 2021; 22:12792. [PMID: 34884597 DOI: 10.3390/ijms222312792] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 11/16/2022] Open
Abstract
The proteins of membrane transporters (MTs) are embedded within membrane-bounded organelles and are the prime targets for improvements in the efficiency of water and nutrient transportation. Their function is to maintain cellular homeostasis by controlling ionic movements across cellular channels from roots to upper plant parts, xylem loading and remobilization of sugar molecules from photosynthesis tissues in the leaf (source) to roots, stem and seeds (sink) via phloem loading. The plant's entire source-to-sink relationship is regulated by multiple transporting proteins in a highly sophisticated manner and driven based on different stages of plant growth and development (PG&D) and environmental changes. The MTs play a pivotal role in PG&D in terms of increased plant height, branches/tiller numbers, enhanced numbers, length and filled panicles per plant, seed yield and grain quality. Dynamic climatic changes disturbed ionic balance (salt, drought and heavy metals) and sugar supply (cold and heat stress) in plants. Due to poor selectivity, some of the MTs also uptake toxic elements in roots negatively impact PG&D and are later on also exported to upper parts where they deteriorate grain quality. As an adaptive strategy, in response to salt and heavy metals, plants activate plasma membranes and vacuolar membrane-localized MTs that export toxic elements into vacuole and also translocate in the root's tips and shoot. However, in case of drought, cold and heat stresses, MTs increased water and sugar supplies to all organs. In this review, we mainly review recent literature from Arabidopsis, halophytes and major field crops such as rice, wheat, maize and oilseed rape in order to argue the global role of MTs in PG&D, and abiotic stress tolerance. We also discussed gene expression level changes and genomic variations within a species as well as within a family in response to developmental and environmental cues.
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Kitaoku Y, Fukamizo T, Kumsaoad S, Ubonbal P, Robinson RC, Suginta W. A structural model for (GlcNAc) 2 translocation via a periplasmic chitooligosaccharide-binding protein from marine Vibrio bacteria. J Biol Chem 2021; 297:101071. [PMID: 34400168 PMCID: PMC8449061 DOI: 10.1016/j.jbc.2021.101071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/04/2021] [Accepted: 08/10/2021] [Indexed: 11/25/2022] Open
Abstract
VhCBP is a periplasmic chitooligosaccharide-binding protein mainly responsible for translocation of the chitooligosaccharide (GlcNAc)2 across the double membranes of marine bacteria. However, structural and thermodynamic understanding of the sugar-binding/-release processes of VhCBP is relatively less. VhCBP displayed the greatest affinity toward (GlcNAc)2, with lower affinity for longer-chain chitooligosaccharides [(GlcNAc)3–4]. (GlcNAc)4 partially occupied the closed sugar-binding groove, with two reducing-end GlcNAc units extending beyond the sugar-binding groove and barely characterized by weak electron density. Mutation of three conserved residues (Trp363, Asp365, and Trp513) to Ala resulted in drastic decreases in the binding affinity toward the preferred substrate (GlcNAc)2, indicating their significant contributions to sugar binding. The structure of the W513A–(GlcNAc)2 complex in a ‘half-open’ conformation unveiled the intermediary step of the (GlcNAc)2 translocation from the soluble CBP in the periplasm to the inner membrane–transporting components. Isothermal calorimetry data suggested that VhCBP adopts the high-affinity conformation to bind (GlcNAc)2, while its low-affinity conformation facilitated sugar release. Thus, chitooligosaccharide translocation, conferred by periplasmic VhCBP, is a crucial step in the chitin catabolic pathway, allowing Vibrio bacteria to thrive in oceans where chitin is their major source of nutrients.
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Affiliation(s)
- Yoshihito Kitaoku
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Tamo Fukamizo
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
| | - Sawitree Kumsaoad
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Prakayfun Ubonbal
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Robert C Robinson
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand; Research Institute of Interdisciplinary Science (RIIS), Okayama University, Okayama, Japan.
| | - Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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Li H, Li X, Xuan Y, Jiang J, Wei Y, Piao Z. Genome Wide Identification and Expression Profiling of SWEET Genes Family Reveals Its Role During Plasmodiophora brassicae-Induced Formation of Clubroot in Brassica rapa. Front Plant Sci 2018; 9:207. [PMID: 29541081 PMCID: PMC5836591 DOI: 10.3389/fpls.2018.00207] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/02/2018] [Indexed: 05/02/2023]
Abstract
Plasmodiophora brassicae is a soil borne pathogen and the causal agent of clubroot, a devastating disease of Brassica crops. The pathogen lives inside roots, and hijacks nutrients from the host plants. It is suggested that clubroot galls created an additional nutrient sink in infected roots. However, the molecular mechanism underlying P. brassicae infection and sugar transport is unclear. Here, we analyzed sugar contents in leaves and roots before and after P. brassicae infection using a pair of Chinese cabbage near-isogenic lines (NILs), carrying either a clubroot resistant (CR) or susceptible (CS) allele at the CRb locus. P. brassicae infection caused significant increase of glucose and fructose contents in the root of CS-NIL compared to CR-NIL, suggesting that sugar translocation and P. brassicae growth are closely related. Among 32 B. rapa SWEET homologs, several BrSWEETs belonging to Clade I and III were significantly up-regulated, especially in CS-NIL upon P. brassicae infection. Moreover, Arabidopsis sweet11 mutant exhibited slower gall formation compared to the wild-type plants. Our studies suggest that P. brassicae infection probably triggers active sugar translocation between the sugar producing tissues and the clubbed tissues, and the SWEET family genes are involved in this process.
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Affiliation(s)
- Hong Li
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Xiaonan Li
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Yuanhu Xuan
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Jing Jiang
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Yangdou Wei
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Zhongyun Piao
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
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Abstract
Vascular plants transport energy in the form of sugars from the leaves where they are produced to sites of active growth. The mass flow of sugars through the phloem vascular system is determined by the sap flow rate and the sugar concentration. If the concentration is low, little energy is transferred from source to sink. If it is too high, sap viscosity impedes flow. An interesting question is therefore at which concentration is the sugar flow optimal. Optimization of sugar flow and transport efficiency predicts optimal concentrations of 23.5 per cent (if the pressure differential driving the flow is independent of concentration) and 34.5 per cent (if the pressure is proportional to concentration). Data from more than 50 experiments (41 species) collected from the literature show an average concentration in the range from 18.2 per cent (all species) to 21.1 per cent (active loaders), suggesting that the phloem vasculature is optimized for efficient transport at constant pressure and that active phloem loading may have developed to increase transport efficiency.
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Affiliation(s)
- Kaare H Jensen
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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Jensen KH, Lee J, Bohr T, Bruus H, Holbrook NM, Zwieniecki MA. Optimality of the Münch mechanism for translocation of sugars in plants. J R Soc Interface 2011; 8:1155-65. [PMID: 21245117 PMCID: PMC3119876 DOI: 10.1098/rsif.2010.0578] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/21/2010] [Indexed: 11/12/2022] Open
Abstract
Plants require effective vascular systems for the transport of water and dissolved molecules between distal regions. Their survival depends on the ability to transport sugars from the leaves where they are produced to sites of active growth; a flow driven, according to the Münch hypothesis, by osmotic gradients generated by differences in sugar concentration. The length scales over which sugars are produced (Lleaf) and over which they are transported (L(stem)), as well as the radius r of the cylindrical phloem cells through which the transport takes place, vary among species over several orders of magnitude; a major unsettled question is whether the Münch transport mechanism is effective over this wide range of sizes. Optimization of translocation speed predicts a scaling relation between radius r and the characteristic lengths as r∼(Lleaf Lstem)1/3. Direct measurements using novel in vivo techniques and biomimicking microfluidic devices support this scaling relation and provide the first quantitative support for a unified mechanism of sugar translocation in plants spanning several orders of magnitude in size. The existence of a general scaling law for phloem dimensions provides a new framework for investigating the physical principles governing the morphological diversity of plants.
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Affiliation(s)
- K. H. Jensen
- Centre for Fluid Dynamics, Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, 2800 Kongens Lyngby, Denmark
| | - J. Lee
- Division of Engineering, Brown University, Providence, RI 02912, USA
| | - T. Bohr
- Centre for Fluid Dynamics, Department of Physics, Technical University of Denmark, DTU Physics Building 309, 2800 Kongens Lyngby, Denmark
| | - H. Bruus
- Centre for Fluid Dynamics, Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, 2800 Kongens Lyngby, Denmark
| | - N. M. Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
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Ooume K, Inoue Y, Soga K, Wakabayashi K, Fujii S, Yamamoto R, Hoson T. Cellular basis of growth suppression by submergence in azuki bean epicotyls. Ann Bot 2009; 103:325-32. [PMID: 18940853 PMCID: PMC2707313 DOI: 10.1093/aob/mcn198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 06/12/2008] [Accepted: 08/18/2008] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Complete submergence severely reduces growth rate and productivity of terrestrial plants, but much remains to be elucidated regarding the mechanisms involved. The aim of this study was to clarify the cellular basis of growth suppression by submergence in stems. METHODS The effects of submergence on the viscoelastic extensibility of the cell wall and the cellular osmotic concentration were studied in azuki bean epicotyls. Modifications by submergence to chemical properties of the cell wall; levels of osmotic solutes and their translocation from the seed to epicotyls; and apoplastic pH and levels of ATP and ethanol were also examined. These cellular events underwater were compared in etiolated and in light-grown seedlings. KEY RESULTS Under submergence, the osmotic concentration of the cell sap was substantially decreased via decreased concentrations of organic compounds including sugars and amino acids. In contrast, the viscoelastic extensibility of the cell wall was kept high. Submergence also decreased ATP and increased the pH of the apoplastic solution. Alcoholic fermentation was stimulated underwater, but the resulting accumulated ethanol was not directly involved in growth suppression. Light partially relieved the inhibitory effects of submergence on growth, osmoregulation and sugar translocation. CONCLUSIONS A decrease in the levels of osmotic solutes is a main cause of underwater growth suppression in azuki bean epicotyls. This may be brought about by suppression of solute uptake via breakdown of the H(+) gradient across the plasma membrane due to a decrease in ATP. The involvement of cell wall properties in underwater growth suppression remains to be fully elucidated.
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Affiliation(s)
- Kentaro Ooume
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Yuki Inoue
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Kouichi Soga
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Kazuyuki Wakabayashi
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
| | - Shuhei Fujii
- Laboratory of Biology, Tezukayama University, Nara 631-8585, Japan
| | - Ryoichi Yamamoto
- Laboratory of Biology, Tezukayama University, Nara 631-8585, Japan
| | - Takayuki Hoson
- Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan
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Parvez MM, Wakabayashi K, Hoson T, Kamisaka S. White light-induced sugar distribution controls growth and osmotic properties in the coleoptile and the first leaf in Zea mays seedlings. Physiol Plant 1998; 102:1-8. [PMID: 35359124 DOI: 10.1034/j.1399-3054.1998.1020101.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The correlation of white light-induced changes in osmotic concentration in the coleoptile and the first leaf and the growth rate of these organs in maize seedlings, was examined in relation to sugar distribution and invertase activity. One hour irradiation with white light decreased the osmotic concentration in basal zones of the coleoptile and increased it in the apical zones of the first leaf. The change in the osmotic concentration was positively correlated with the growth rate of both organs. The amount of total osmotic solutes in each zone was highly correlated with that of soluble sugars. Light decreased the activity of wall-bound invertase in the coleoptile, but increased it in the first leaf. A high correlation existed between the content of soluble sugars and invertase activity in both organs. During 1 h incubation in the light, ca 2 µmol of soluble sugars per seedling was lost from the coleoptile and gained in the first leaf. Light promoted sugar exudation from the excised coleoptile, but the amount of soluble sugar exuded represented 5% of sugar loss from the coleoptile in intact seedlings. These results indicate that in maize seedlings white light controls the growth rate of the coleoptile and the first leaf through the osmotic concentration. Light may have an osmoregulatory function in the control of sugar distribution between the coleoptile and the first leaf by regulating the activity of wall-bound invertase.
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Affiliation(s)
- Mohammad Masud Parvez
- M. M. Parvez, K. Wakabayashi, T. Hoson and S. Kamisaka (corresponding author, e-mail jp), Dept of Biology, Fac. of Science, Osaka City Univ., Sumiyoshi-ku, Osaka 558, Japan
| | - Kazuyuki Wakabayashi
- M. M. Parvez, K. Wakabayashi, T. Hoson and S. Kamisaka (corresponding author, e-mail jp), Dept of Biology, Fac. of Science, Osaka City Univ., Sumiyoshi-ku, Osaka 558, Japan
| | - Takayuki Hoson
- M. M. Parvez, K. Wakabayashi, T. Hoson and S. Kamisaka (corresponding author, e-mail jp), Dept of Biology, Fac. of Science, Osaka City Univ., Sumiyoshi-ku, Osaka 558, Japan
| | - Seiichiro Kamisaka
- M. M. Parvez, K. Wakabayashi, T. Hoson and S. Kamisaka (corresponding author, e-mail jp), Dept of Biology, Fac. of Science, Osaka City Univ., Sumiyoshi-ku, Osaka 558, Japan
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