1
|
Heeney M, Frank MH. The mRNA mobileome: challenges and opportunities for deciphering signals from the noise. THE PLANT CELL 2023; 35:1817-1833. [PMID: 36881847 DOI: 10.1093/plcell/koad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 05/30/2023]
Abstract
Organismal communication entails encoding a message that is sent over space or time to a recipient cell, where that message is decoded to activate a downstream response. Defining what qualifies as a functional signal is essential for understanding intercellular communication. In this review, we delve into what is known and unknown in the field of long-distance messenger RNA (mRNA) movement and draw inspiration from the field of information theory to provide a perspective on what defines a functional signaling molecule. Although numerous studies support the long-distance movement of hundreds to thousands of mRNAs through the plant vascular system, only a small handful of these transcripts have been associated with signaling functions. Deciphering whether mobile mRNAs generally serve a role in plant communication has been challenging, due to our current lack of understanding regarding the factors that influence mRNA mobility. Further insight into unsolved questions regarding the nature of mobile mRNAs could provide an understanding of the signaling potential of these macromolecules.
Collapse
Affiliation(s)
- Michelle Heeney
- Plant Biology Section, School of Integrative Plant Science, Cornell University, 14853 Ithaca, NY, USA
| | - Margaret H Frank
- Plant Biology Section, School of Integrative Plant Science, Cornell University, 14853 Ithaca, NY, USA
| |
Collapse
|
2
|
Kehr J, Morris RJ, Kragler F. Long-Distance Transported RNAs: From Identity to Function. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:457-474. [PMID: 34910585 DOI: 10.1146/annurev-arplant-070121-033601] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
There is now a wealth of data, from different plants and labs and spanning more than two decades, which unequivocally demonstrates that RNAs can be transported over long distances, from the cell where they are transcribed to distal cells in other tissues. Different types of RNA molecules are transported, including micro- and messenger RNAs. Whether these RNAs are selected for transport and, if so, how they are selected and transported remain, in general, open questions. This aspect is likely not independent of the biological function and relevance of the transported RNAs, which are in most cases still unclear. In this review, we summarize the experimental data supporting selectivity or nonselectivity of RNA translocation and review the evidence for biological functions. After discussing potential issues regarding the comparability between experiments, we propose criteria that need to be critically evaluated to identify important signaling RNAs.
Collapse
Affiliation(s)
- Julia Kehr
- Department of Biology, Institute for Plant Sciences and Microbiology, Universität Hamburg, Hamburg, Germany;
| | - Richard J Morris
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom;
| | - Friedrich Kragler
- Department II, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany;
| |
Collapse
|
3
|
Lohaus G. Review primary and secondary metabolites in phloem sap collected with aphid stylectomy. JOURNAL OF PLANT PHYSIOLOGY 2022; 271:153645. [PMID: 35217406 DOI: 10.1016/j.jplph.2022.153645] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Phloem plays a central role in assimilate transport as well as in the transport of several secondary compounds. In order to study the chemical composition of phloem sap, different methods have been used for its collection, including stem incisions, EDTA-facilitated exudation or aphid stylectomy. Each collection method has several advantages and disadvantages and, unfortunately, the reported metabolite profiles and concentrations depend on the method used for exudate collection. This review therefore primarily focusses on sugars, amino acids, inorganic ions and further transported compounds like organic acids, nucleotides, phytohormons, defense signals, and lipophilic substances in the phloem sap obtained by aphid stylectomy to facilitate comparability of the data.
Collapse
Affiliation(s)
- Gertrud Lohaus
- Molecular Plant Science/Plant Biochemistry, University of Wuppertal, Gaußstr. 20, 42119, Wuppertal, Germany.
| |
Collapse
|
4
|
Hoffmann-Benning S. Collection and Analysis of Phloem Lipids. Methods Mol Biol 2021; 2295:351-361. [PMID: 34047986 DOI: 10.1007/978-1-0716-1362-7_19] [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: 03/11/2023]
Abstract
The plant phloem is a long-distance conduit for the transport of assimilates but also of mobile developmental and stress signals. These signals can be sugars, metabolites, amino acids, peptides, proteins, microRNA, or mRNA. Yet small lipophilic molecules such as oxylipins and, more recently, phospholipids have emerged as possible long-distance signals as well. Analysis of phloem (phospho)lipids, however, requires enrichment, purification, and sensitive analysis. This chapter describes the EDTA-facilitated approach of phloem exudate collection, phase partitioning against chloroform-methanol for lipid separation and enrichment, and analysis/identification of phloem lipids using LC-MS with multiplexed collision induced dissociation (CID).
Collapse
Affiliation(s)
- Susanne Hoffmann-Benning
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
5
|
Kondhare KR, Patil NS, Banerjee AK. A historical overview of long-distance signalling in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4218-4236. [PMID: 33682884 DOI: 10.1093/jxb/erab048] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 02/01/2021] [Indexed: 06/12/2023]
Abstract
Be it a small herb or a large tree, intra- and intercellular communication and long-distance signalling between distant organs are crucial for every aspect of plant development. The vascular system, comprising xylem and phloem, acts as a major conduit for the transmission of long-distance signals in plants. In addition to expanding our knowledge of vascular development, numerous reports in the past two decades revealed that selective populations of RNAs, proteins, and phytohormones function as mobile signals. Many of these signals were shown to regulate diverse physiological processes, such as flowering, leaf and root development, nutrient acquisition, crop yield, and biotic/abiotic stress responses. In this review, we summarize the significant discoveries made in the past 25 years, with emphasis on key mobile signalling molecules (mRNAs, proteins including RNA-binding proteins, and small RNAs) that have revolutionized our understanding of how plants integrate various intrinsic and external cues in orchestrating growth and development. Additionally, we provide detailed insights on the emerging molecular mechanisms that might control the selective trafficking and delivery of phloem-mobile RNAs to target tissues. We also highlight the cross-kingdom movement of mobile signals during plant-parasite relationships. Considering the dynamic functions of these signals, their implications in crop improvement are also discussed.
Collapse
Affiliation(s)
- Kirtikumar R Kondhare
- Plant Molecular Biology Unit, Biochemical Sciences Division, CSIR-National Chemical Laboratory (NCL) Pune, Maharashtra, India
| | - Nikita S Patil
- Biology Division, Indian Institute of Science Education and Research (IISER) Pune, Maharashtra, India
| | - Anjan K Banerjee
- Biology Division, Indian Institute of Science Education and Research (IISER) Pune, Maharashtra, India
| |
Collapse
|
6
|
The interplay of phloem-mobile signals in plant development and stress response. Biosci Rep 2021; 40:226464. [PMID: 32955092 PMCID: PMC7538631 DOI: 10.1042/bsr20193329] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 01/28/2023] Open
Abstract
Plants integrate a variety of biotic and abiotic factors for optimal growth in their given environment. While some of these responses are local, others occur distally. Hence, communication of signals perceived in one organ to a second, distal part of the plant and the coordinated developmental response require an intricate signaling system. To do so, plants developed a bipartite vascular system that mediates the uptake of water, minerals, and nutrients from the soil; transports high-energy compounds and building blocks; and traffics essential developmental and stress signals. One component of the plant vasculature is the phloem. The development of highly sensitive mass spectrometry and molecular methods in the last decades has enabled us to explore the full complexity of the phloem content. As a result, our view of the phloem has evolved from a simple transport path of photoassimilates to a major highway for pathogens, hormones and developmental signals. Understanding phloem transport is essential to comprehend the coordination of environmental inputs with plant development and, thus, ensure food security. This review discusses recent developments in its role in long-distance signaling and highlights the role of some of the signaling molecules. What emerges is an image of signaling paths that do not just involve single molecules but rather, quite frequently an interplay of several distinct molecular classes, many of which appear to be transported and acting in concert.
Collapse
|
7
|
Biedenkopf D, Will T, Knauer T, Jelonek L, Furch ACU, Busche T, Koch A. Systemic spreading of exogenous applied RNA biopesticides in the crop plant Hordeum vulgare. ACTA ACUST UNITED AC 2020. [DOI: 10.1186/s41544-020-00052-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
8
|
De Zaeytijd J, Chen P, Scheys F, Subramanyam K, Dubiel M, De Schutter K, Smagghe G, Van Damme EJ. Involvement of OsRIP1, a ribosome-inactivating protein from rice, in plant defense against Nilaparvata lugens. PHYTOCHEMISTRY 2020; 170:112190. [PMID: 31731237 DOI: 10.1016/j.phytochem.2019.112190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/24/2019] [Accepted: 10/27/2019] [Indexed: 06/10/2023]
Abstract
Rice is the most important staple food in the world, but rice production is challenged by several biotic stress factors like viruses, bacteria, fungi and pest insects. One of the most notorious pest insects is Nilaparvata lugens, commonly known as the brown planthopper, which feeds on rice phloem sap and can cause serious damage to rice fields. In order to protect themselves, plants express a wide array of defense proteins such as ribosome-inactivating proteins (RIPs). This study shows that the expression of 'OsRIP1' is highly induced in rice plants infested with N. lugens, with transcript levels more than 100-fold upregulated in infested plants compared to non-infested plants. Furthermore, recombinant OsRIP1 was toxic for brown planthoppers when administered through liquid artificial diet. OsRIP1 inactivated insect ribosomes in vitro, suggesting that its toxicity relates to the enzymatic activity of OsRIP1. Over-expression of OsRIP1 in transgenic rice plants did not affect the performance of insects reared on these plants, most likely due to insufficient concentrations of OsRIP1 in the phloem. The data obtained in this research indicate that OsRIP1 can play a role in plant defense against herbivorous insects.
Collapse
Affiliation(s)
- Jeroen De Zaeytijd
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Pengyu Chen
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Freja Scheys
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Kondeti Subramanyam
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Malgorzata Dubiel
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium; Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Kristof De Schutter
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Guy Smagghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium
| | - Els Jm Van Damme
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.
| |
Collapse
|
9
|
Kloth KJ, Kormelink R. Defenses against Virus and Vector: A Phloem-Biological Perspective on RTM- and SLI1-Mediated Resistance to Potyviruses and Aphids. Viruses 2020; 12:E129. [PMID: 31979012 PMCID: PMC7077274 DOI: 10.3390/v12020129] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/17/2020] [Accepted: 01/19/2020] [Indexed: 12/12/2022] Open
Abstract
Combining plant resistance against virus and vector presents an attractive approach to reduce virus transmission and virus proliferation in crops. RestrictedTobacco-etch virus Movement (RTM) genes confer resistance to potyviruses by limiting their long-distance transport. Recently, a close homologue of one of the RTM genes, SLI1, has been discovered but this gene instead confers resistance to Myzus persicae aphids, a vector of potyviruses. The functional connection between resistance to potyviruses and aphids, raises the question whether plants have a basic defense system in the phloem against biotic intruders. This paper provides an overview on restricted potyvirus phloem transport and restricted aphid phloem feeding and their possible interplay, followed by a discussion on various ways in which viruses and aphids gain access to the phloem sap. From a phloem-biological perspective, hypotheses are proposed on the underlying mechanisms of RTM- and SLI1-mediated resistance, and their possible efficacy to defend against systemic viruses and phloem-feeding vectors.
Collapse
Affiliation(s)
- Karen J. Kloth
- Laboratory of Entomology, Wageningen University and Research, 6700 AA Wageningen, The Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Wageningen University and Research, 6700 AA Wageningen, The Netherlands;
| |
Collapse
|
10
|
Abstract
Mobility assays coupled with RNA profiling have revealed the presence of hundreds of full-length non-cell-autonomous messenger RNAs that move through the whole plant via the phloem cell system. Monitoring the movement of these RNA signals can be difficult and time consuming. Here we describe a simple, virus-based system for surveying RNA movement by replacing specific sequences within the viral RNA genome of potato virus X (PVX) that are critical for movement with other sequences that facilitate movement. PVX is a RNA virus dependent on three small proteins that facilitate cell-to-cell transport and a coat protein (CP) required for long-distance spread of PVX. Deletion of the CP blocks movement, whereas replacing the CP with phloem-mobile RNA sequences reinstates mobility. Two experimental models validating this assay system are discussed. One involves the movement of the flowering locus T RNA that regulates floral induction and the second involves movement of StBEL5, a long-distance RNA signal that regulates tuber formation in potato.
Collapse
Affiliation(s)
- Zhiming Yu
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | | | - Pengcheng Zhang
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yiguo Hong
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China.
- Warwick-Hangzhou RNA Signaling Joint Laboratory, School of Life Sciences, University of Warwick, Warwick, UK.
- Worcester-Hangzhou Joint Molecular Plant Health Laboratory, Institute of Science and the Environment, University of Worcester, Worcester, UK.
| | | |
Collapse
|
11
|
Thomas HR, Frank MH. Connecting the pieces: uncovering the molecular basis for long-distance communication through plant grafting. THE NEW PHYTOLOGIST 2019; 223:582-589. [PMID: 30834529 DOI: 10.1111/nph.15772] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/19/2019] [Indexed: 05/23/2023]
Abstract
Vascular plants are wired with a remarkable long-distance communication system. This network can span from as little as a few centimeters (or less) in species like Arabidopsis, up to 100 m in the tallest giant sequoia, linking distant organ systems into a unified, multicellular organism. Grafting is a fundamental technique that allows researchers to physically break apart and reassemble the long-distance transport system, enabling the discovery of molecular signals that underlie intraorganismal communication. In this review, we highlight how plant grafting has facilitated the discovery of new long-distance signaling molecules that function in coordinating developmental transitions, abiotic and biotic responses, and cross-species interactions. This rapidly expanding area of research offers sustainable approaches for improving plant performance in the laboratory, the field, the orchard, and beyond.
Collapse
Affiliation(s)
- Hannah R Thomas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Margaret H Frank
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| |
Collapse
|
12
|
Liu L, Chen X. Intercellular and systemic trafficking of RNAs in plants. NATURE PLANTS 2018; 4:869-878. [PMID: 30390090 PMCID: PMC7155933 DOI: 10.1038/s41477-018-0288-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/21/2018] [Indexed: 05/14/2023]
Abstract
Plants have evolved dynamic and complex networks of cell-to-cell communication to coordinate and adapt their growth and development to a variety of environmental changes. In addition to small molecules, such as metabolites and phytohormones, macromolecules such as proteins and RNAs also act as signalling agents in plants. As information molecules, RNAs can move locally between cells through plasmodesmata, and over long distances through phloem. Non-cell-autonomous RNAs may act as mobile signals to regulate plant development, nutrient allocation, gene silencing, antiviral defence, stress responses and many other physiological processes in plants. Recent work has shed light on mobile RNAs and, in some cases, uncovered their roles in intercellular and systemic signalling networks. This review summarizes the current knowledge of local and systemic RNA movement, and discusses the potential regulatory mechanisms and biological significance of RNA trafficking in plants.
Collapse
Affiliation(s)
- Lin Liu
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
- Longhua Bioindustry and Innovation Research Institute, Shenzhen University, Shenzhen, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA.
| |
Collapse
|
13
|
Kehr J, Kragler F. Long distance RNA movement. THE NEW PHYTOLOGIST 2018; 218:29-40. [PMID: 29418002 DOI: 10.1111/nph.15025] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/28/2017] [Indexed: 05/06/2023]
Abstract
Contents Summary 29 I. Introduction 29 II. Phloem as a conduit for macromolecules 30 III. Classes of phloem transported RNAs and their function 32 IV. Mode of RNA transport 35 V. Conclusions 37 Acknowledgements 37 References 37 SUMMARY: In higher plants, small noncoding RNAs and large messenger RNA (mRNA) molecules are transported between cells and over long distances via the phloem. These large macromolecules are thought to get access to the sugar-conducting phloem vessels via specialized plasmodesmata (PD). Analyses of the phloem exudate suggest that all classes of RNA molecules, including silencing-induced RNAs (siRNAs), micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNA (rRNAs) and mRNAs, are transported via the vasculature to distant tissues. Although the functions of mobile siRNAs and miRNAs as signalling molecules are well established, we lack a profound understanding of mobile mRNA function(s) in recipient cells and tissues, and how they are selected for transport. A surprisingly high number of up to thousands of mRNAs were described in diverse plant species such as cucumber, pumpkin, Arabidopsis and grapevine to move long distances over graft junctions to distinct body parts. In this review, we present an overview of the classes of mobile RNAs, the potential mechanisms facilitating RNA long-distance transport, and the roles of mobile RNAs in regulating transcription and translation. Furthermore, we address potential function(s) of mobile protein-encoding mRNAs with respect to their characteristics and evolutionary constraints.
Collapse
Affiliation(s)
- Julia Kehr
- Biocenter Klein Flottbek, Molekulare Pflanzengenetik, University Hamburg, Ohnhorststr. 18, Hamburg 22609, Germany
| | - Friedrich Kragler
- Department II, Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, Potsdam-Golm 14476, Germany
| |
Collapse
|
14
|
Kanvil S, Pham J, Lopez-Cobollo R, Selby M, Bennett M, Beckingham C, Powell G, Turnbull C. Cucurbit extrafascicular phloem has strong negative impacts on aphids and is not a preferred feeding site. PLANT, CELL & ENVIRONMENT 2017; 40:2780-2789. [PMID: 28779505 DOI: 10.1111/pce.13053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 07/31/2017] [Indexed: 05/23/2023]
Abstract
Cucurbits have long been known to possess two types of phloem: fascicular (FP) within vascular bundles and extrafascicular phloem (EFP) surrounding vascular bundles and scattered through the cortex. Recently, their divergent composition was revealed, with FP having high sugar content consistent with conventional phloem, but EFP having much lower sugar levels and a very different proteome. However, the evolutionary advantages of possessing both FP and EFP have remained unclear. Here, we present four lines of quantitative evidence that together support the hypothesis that FP represents a typical phloem and is an attractive diet for aphids, whereas aphids avoid feeding on EFP. First, aphid stylet track endings were more abundant near the abaxial FP element of minor veins, suggesting a feeding preference for FP over EFP. Second, sugar profiles from stylet exudates were wholly consistent with FP origins, further supporting preference for FP and avoidance of EFP. Third, supplementation of EFP exudate into artificial diets confirmed an aversion to EFP in choice experiments. Finally, EFP exudate had negative effects on aphid performance. On the basis of aphids' inability to thrive on EFP, we conclude that EFP is atypical and perhaps should not be classed as a phloem system.
Collapse
Affiliation(s)
- Sadia Kanvil
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Jasmine Pham
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Rosa Lopez-Cobollo
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Martin Selby
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Mark Bennett
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | | | - Glen Powell
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Colin Turnbull
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| |
Collapse
|
15
|
Abstract
The plant vascular system plays a central role in coordinating physiological and developmental events through delivery of both essential nutrients and long-distance signaling agents. The enucleate phloem sieve tube system of the angiosperms contains a broad spectrum of RNA species. Grafting and transcriptomics studies have indicated that several thousand mRNAs move long distances from source organs to meristematic sink tissues. Ribonucleoprotein complexes play a pivotal role as stable RNA-delivery systems for systemic translocation of cargo RNA. In this review, we assess recent progress in the characterization of phloem and plasmodesmal transport as an integrated local and systemic communication network. We discuss the roles of phloem-mobile small RNAs in epigenetic events, including meristem development and genome stability, and the delivery of mRNAs to specific tissues in response to environmental inputs. A large body of evidence now supports a model in which phloem-mobile RNAs act as critical components of gene regulatory networks involved in plant growth, defense, and crop yield at the whole-plant level.
Collapse
Affiliation(s)
- Byung-Kook Ham
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, California 95616; ,
| | - William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, California 95616; ,
| |
Collapse
|
16
|
Hannapel DJ, Banerjee AK. Multiple Mobile mRNA Signals Regulate Tuber Development in Potato. PLANTS 2017; 6:plants6010008. [PMID: 28208608 PMCID: PMC5371767 DOI: 10.3390/plants6010008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/24/2017] [Accepted: 01/30/2017] [Indexed: 12/17/2022]
Abstract
Included among the many signals that traffic through the sieve element system are full-length mRNAs that function to respond to the environment and to regulate development. In potato, several mRNAs that encode transcription factors from the three-amino-loop-extension (TALE) superfamily move from leaves to roots and stolons via the phloem to control growth and signal the onset of tuber formation. This RNA transport is enhanced by short-day conditions and is facilitated by RNA-binding proteins from the polypyrimidine tract-binding family of proteins. Regulation of growth is mediated by three mobile mRNAs that arise from vasculature in the leaf. One mRNA, StBEL5, functions to activate growth, whereas two other, sequence-related StBEL's, StBEL11 and StBEL29, function antagonistically to repress StBEL5 target genes involved in promoting tuber development. This dynamic system utilizes closely-linked phloem-mobile mRNAs to control growth in developing potato tubers. In creating a complex signaling pathway, potato has evolved a long-distance transport system that regulates underground organ development through closely-associated, full-length mRNAs that function as either activators or repressors.
Collapse
Affiliation(s)
- David J Hannapel
- Plant Biology Major, 253 Horticulture Hall, Iowa State University, Ames, IA 50011-1100, USA.
| | - Anjan K Banerjee
- Biology Division, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
| |
Collapse
|
17
|
Lopez-Cobollo RM, Filippis I, Bennett MH, Turnbull CGN. Comparative proteomics of cucurbit phloem indicates both unique and shared sets of proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:633-647. [PMID: 27472661 DOI: 10.1111/tpj.13288] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/15/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
Cucurbits are well-studied models for phloem biology but unusually possess both fascicular phloem (FP) within vascular bundles and additional extrafascicular phloem (EFP). Although the functional differences between the two systems are not yet clear, sugar analysis and limited protein profiling have established that FP and EFP have divergent compositions. Here we report a detailed comparative proteomics study of FP and EFP in two cucurbits, pumpkin and cucumber. We re-examined the sites of exudation by video microscopy, and confirmed that in both species, the spontaneous exudate following tissue cutting derives almost exclusively from EFP. Comparative gel electrophoresis and mass spectrometry-based proteomics of exudates, sieve element contents and microdissected stem tissues established that EFP and FP profiles are highly dissimilar, and that there are also species differences. Searches against cucurbit databases enabled identification of more than 300 FP proteins from each species. Few of the detected proteins (about 10%) were shared between the sieve element contents of FP and EFP, and enriched Gene Ontology categories also differed. To explore quantitative differences in the proteomes, we developed multiple reaction monitoring methods for cucumber proteins that are representative markers for FP or EFP and assessed exudate composition at different times after tissue cutting. Based on failure to detect FP markers in exudate samples, we conclude that FP is blocked very rapidly and therefore makes a minimal contribution to the exudates. Overall, the highly divergent contents of FP and EFP indicate that they are substantially independent vascular compartments.
Collapse
Affiliation(s)
| | - Ioannis Filippis
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Mark H Bennett
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Colin G N Turnbull
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| |
Collapse
|
18
|
Figueroa-Yañez L, Pereira-Santana A, Arroyo-Herrera A, Rodriguez-Corona U, Sanchez-Teyer F, Espadas-Alcocer J, Espadas-Gil F, Barredo-Pool F, Castaño E, Rodriguez-Zapata LC. RAP2.4a Is Transported through the Phloem to Regulate Cold and Heat Tolerance in Papaya Tree (Carica papaya cv. Maradol): Implications for Protection Against Abiotic Stress. PLoS One 2016; 11:e0165030. [PMID: 27764197 PMCID: PMC5072549 DOI: 10.1371/journal.pone.0165030] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 10/05/2016] [Indexed: 11/18/2022] Open
Abstract
Plants respond to stress through metabolic and morphological changes that increase their ability to survive and grow. To this end, several transcription factor families are responsible for transmitting the signals that are required for these changes. Here, we studied the transcription factor superfamily AP2/ERF, particularly, RAP2.4 from Carica papaya cv. Maradol. We isolated four genes (CpRap2.4a, CpRAap2.4b, CpRap2.1 and CpRap2.10), and an in silico analysis showed that the four genes encode proteins that contain a conserved APETALA2 (AP2) domain located within group I and II transcription factors of the AP2/ERF superfamily. Semiquantitative PCR experiments indicated that each CpRap2 gene is differentially expressed under stress conditions, such as extreme temperatures. Moreover, genetic transformants of tobacco plants overexpressing CpRap2.4a and CpRap2.4b genes show a high level of tolerance to cold and heat stress compared to non-transformed plants. Confocal microscopy analysis of tobacco transgenic plants showed that CpRAP2.4a and CpRAP2.4b proteins were mainly localized to the nuclei of cells from the leaves and roots and also in the sieve elements. Moreover, the movement of CpRap2.4a RNA in tobacco grafting was analyzed. Our results indicate that CpRap2.4a and CpRap2.4b RNA in the papaya tree have a functional role in the response to stress conditions such as exposure to extreme temperatures via direct translation outside the parental RNA cell.
Collapse
Affiliation(s)
- Luis Figueroa-Yañez
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | | | - Ana Arroyo-Herrera
- Laboratorio de Farmacología, Facultad de Química, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Ulises Rodriguez-Corona
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Felipe Sanchez-Teyer
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Jorge Espadas-Alcocer
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Francisco Espadas-Gil
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Felipe Barredo-Pool
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | - Enrique Castaño
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Mérida, Yucatán, México
| | | |
Collapse
|
19
|
Figueroa-Yañez L, Pereira-Santana A, Arroyo-Herrera A, Rodriguez-Corona U, Sanchez-Teyer F, Espadas-Alcocer J, Espadas-Gil F, Barredo-Pool F, Castaño E, Rodriguez-Zapata LC. RAP2.4a Is Transported through the Phloem to Regulate Cold and Heat Tolerance in Papaya Tree (Carica papaya cv. Maradol): Implications for Protection Against Abiotic Stress. PLoS One 2016; 11:e0165030. [DOI: https:/doi.org/10.1371/journal.pone.0165030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024] Open
|
20
|
Hu C, Ham BK, El-Shabrawi HM, Alexander D, Zhang D, Ryals J, Lucas WJ. Proteomics and metabolomics analyses reveal the cucurbit sieve tube system as a complex metabolic space. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:442-54. [PMID: 27155400 DOI: 10.1111/tpj.13209] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 04/22/2016] [Accepted: 04/28/2016] [Indexed: 05/07/2023]
Abstract
The plant vascular system, and specifically the phloem, plays a pivotal role in allocation of fixed carbon to developing sink organs. Although the processes involved in loading and unloading of sugars and amino acids are well characterized, little information is available regarding the nature of other metabolites in the sieve tube system (STS) at specific sites along the pathway. Here, we elucidate spatial features of metabolite composition mapped with phloem enzymes along the cucurbit STS. Phloem sap (PS) was collected from the loading (source), unloading (apical sink region) and shoot-root junction regions of cucumber, watermelon and pumpkin. Our PS analyses revealed significant differences in the metabolic and proteomic profiles both along the source-sink pathway and between the STSs of these three cucurbits. In addition, metabolite profiles established for PS and vascular tissue indicated the presence of distinct compositions, consistent with the operation of the STS as a unique symplasmic domain. In this regard, at various locations along the STS we could map metabolites and their related enzymes to specific metabolic pathways. These findings are discussed with regard to the function of the STS as a unique and highly complex metabolic space within the plant vascular system.
Collapse
Affiliation(s)
- Chaoyang Hu
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, SJTU-University of Adelaide Joint Centre for Agriculture and Health, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Byung-Kook Ham
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA
| | - Hattem M El-Shabrawi
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA
- Plant Biotechnology Department, National Research Center, El-Behouth St, Dokki, Giza, 12622, Egypt
| | | | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, SJTU-University of Adelaide Joint Centre for Agriculture and Health, Shanghai Jiao Tong University, Shanghai, 200240, China
| | | | - William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA, 95616, USA.
| |
Collapse
|
21
|
Carella P, Wilson DC, Kempthorne CJ, Cameron RK. Vascular Sap Proteomics: Providing Insight into Long-Distance Signaling during Stress. FRONTIERS IN PLANT SCIENCE 2016; 7:651. [PMID: 27242852 PMCID: PMC4863880 DOI: 10.3389/fpls.2016.00651] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/28/2016] [Indexed: 05/17/2023]
Abstract
The plant vascular system, composed of the xylem and phloem, is important for the transport of water, mineral nutrients, and photosynthate throughout the plant body. The vasculature is also the primary means by which developmental and stress signals move from one organ to another. Due to practical and technological limitations, proteomics analysis of xylem and phloem sap has been understudied in comparison to accessible sample types such as leaves and roots. However, recent advances in sample collection techniques and mass spectrometry technology are making it possible to comprehensively analyze vascular sap proteomes. In this mini-review, we discuss the emerging field of vascular sap proteomics, with a focus on recent comparative studies to identify vascular proteins that may play roles in long-distance signaling and other processes during stress responses in plants.
Collapse
|
22
|
Imamura T, Sekine KT, Yamashita T, Kusano H, Shimada H. Production of recombinant thanatin in watery rice seeds that lack an accumulation of storage starch and proteins. J Biotechnol 2016; 219:28-33. [PMID: 26689479 DOI: 10.1016/j.jbiotec.2015.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 12/08/2015] [Accepted: 12/10/2015] [Indexed: 10/22/2022]
Abstract
Molecular farming is a promising method for producing materials of commercial interest. Plants can be expected to be appropriate hosts for recombinant protein production. However, production in genetically modified plants has two major challenges that must be resolved before its practical use: insufficient accumulation of products and difficulty in establishing methods for their purification. We propose a simple procedure for the production of a desired protein using watery rice seeds lacking an accumulation of storage starch and proteins, a phenotype induced by the introduction of an antisense SPK. We produced a transgenic rice plant containing a gene for an antimicrobial peptide, thanatin, together with antisense SPK. Bioassay and proteome analysis indicated that recombinant thanatin accumulated in an active form in these watery rice seeds. These results suggest that our system worked effectively for the production of thanatin. This procedure enabled easy removal of impurities and simplified the purification process compared with production in leaves. Our system may therefore be a useful technique for the production of desired materials, including proteins.
Collapse
Affiliation(s)
- Tomohiro Imamura
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan
| | - Ken-Taro Sekine
- Iwate Biotechnology Research Center, 22-174-4 Narita, Kitakami, Iwate 024-0003, Japan
| | - Tetsuro Yamashita
- Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Hiroaki Kusano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan
| | - Hiroaki Shimada
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585, Japan.
| |
Collapse
|
23
|
van Bel AJE, Will T. Functional Evaluation of Proteins in Watery and Gel Saliva of Aphids. FRONTIERS IN PLANT SCIENCE 2016; 7:1840. [PMID: 28018380 PMCID: PMC5156713 DOI: 10.3389/fpls.2016.01840] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 11/22/2016] [Indexed: 05/20/2023]
Abstract
Gel and watery saliva are regarded as key players in aphid-pIant interactions. The salivary composition seems to be influenced by the variable environment encountered by the stylet tip. Milieu sensing has been postulated to provide information needed for proper stylet navigation and for the required switches between gel and watery saliva secretion during stylet progress. Both the chemical and physical factors involved in sensing of the stylet's environment are discussed. To investigate the salivary proteome, proteins were collected from dissected gland extracts or artificial diets in a range of studies. We discuss the advantages and disadvantages of either collection method. Several proteins were identified by functional assays or by use of proteomic tools, while most of their functions still remain unknown. These studies disclosed the presence of at least two proteins carrying numerous sulfhydryl groups that may act as the structural backbone of the salivary sheath. Furthermore, cell-wall degrading proteins such a pectinases, pectin methylesterases, polygalacturonases, and cellulases as well as diverse Ca2+-binding proteins (e.g., regucalcin, ARMET proteins) were detected. Suppression of the plant defense may be a common goal of salivary proteins. Salivary proteases are likely involved in the breakdown of sieve-element proteins to invalidate plant defense or to increase the availability of organic N compounds. Salivary polyphenoloxidases, peroxidases and oxidoreductases were suggested to detoxify, e.g., plant phenols. During the last years, an increasing number of salivary proteins have been categorized under the term 'effector'. Effectors may act in the suppression (C002 or MIF cytokine) or the induction (e.g., Mp10 or Mp 42) of plant defense, respectively. A remarkable component of watery saliva seems the protein GroEL that originates from Buchnera aphidicola, the obligate symbiont of aphids and probably reflects an excretory product that induces plant defense responses. Furthermore, chitin fragments in the saliva may trigger defense reactions (e.g., callose deposition). The functions of identified proteins and protein classes are discussed with regard to physical and chemical characteristics of apoplasmic and symplasmic plant compartments.
Collapse
Affiliation(s)
- Aart J. E. van Bel
- Institute of General Botany, Justus-Liebig-UniversityGiessen, Germany
- *Correspondence: Aart J. E. van Bel,
| | - Torsten Will
- Institute of Phytopathology, Justus-Liebig-UniversityGiessen, Germany
- Institute for Resistance Research and Stress Tolerance, Federal Research Centre for Cultivated Plants, Julius-Kühn InstituteQuedlinburg, Germany
| |
Collapse
|
24
|
Saplaoura E, Kragler F. Mobile Transcripts and Intercellular Communication in Plants. DEVELOPMENTAL SIGNALING IN PLANTS 2016; 40:1-29. [DOI: 10.1016/bs.enz.2016.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
25
|
Yang Y, Mao L, Jittayasothorn Y, Kang Y, Jiao C, Fei Z, Zhong GY. Messenger RNA exchange between scions and rootstocks in grafted grapevines. BMC PLANT BIOLOGY 2015; 15:251. [PMID: 26480945 PMCID: PMC4612405 DOI: 10.1186/s12870-015-0626-y] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/23/2015] [Indexed: 05/07/2023]
Abstract
BACKGROUND Grafting has been widely practiced for centuries in the propagation and production of many vegetable and fruit species. However, the underlying molecular and genetic mechanisms for how the graft partners interact with each other to produce a successful graft remain largely unknown. We hypothesized that genome-wide mRNA exchanges, which were recently documented in grafted model plant species, are a general phenomenon widely present in grafted plants, including those in vegetable and fruit species, and have specific genotype- and environment-dependent characteristics modulating plant performance. METHODS Using diagnostic SNPs derived from high throughput genome sequencing, we identified and characterized the patterns of genome-wide mRNA exchanges across graft junctions in grafted grapevines grown in the in vitro and field conditions. RESULTS We identified more than 3000 genes transporting mRNAs across graft junctions. These genes were involved in diverse biological processes and those involved in basic cellular, biosynthetic, catabolic, and metabolic activities, as well as responses to stress and signal transduction, were highly enriched. Field-grown mature grafts had much fewer genes transmitting mRNAs than the in vitro young grafts (987 vs. 2679). These mobile mRNAs could move directionally or bi-directionally between scions and rootstocks. The mRNA transmission rates of these genes were generally low, with 65% or more having transmission rates lower than 0.01. Furthermore, genotypes, graft combinations and growth environments had impact on the directions of mRNA movement as well as the numbers and species of mRNAs being exchanged. Moreover, we found evidence for the presences of both passive and selective mechanisms underlying long distance mRNA trafficking in grafted grapevines. CONCLUSIONS We extended the studies of mRNA exchanges in model species to grapevines and demonstrated that genomic-scale mRNA exchange across graft junctions occurred in grapevines in a passive or genotype and environment-dependent manner.
Collapse
Affiliation(s)
- Yingzhen Yang
- United States Department of Agriculture, Agricultural Research Service, Grape Genetics Research Unit, Geneva, NY, 14456, USA.
| | - Linyong Mao
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA.
- Present address: Department of Biochemistry & Molecular Biology, Howard University, 520 W Street, NW, Washington, D. C, 20059, USA.
| | - Yingyos Jittayasothorn
- United States Department of Agriculture, Agricultural Research Service, Grape Genetics Research Unit, Geneva, NY, 14456, USA.
- Present address: Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Youngmin Kang
- United States Department of Agriculture, Agricultural Research Service, Grape Genetics Research Unit, Geneva, NY, 14456, USA.
- Present address: K-herb Research Center, Korea Institute of Oriental Medicine, Deajeon, 305-811, Republic of Korea.
| | - Chen Jiao
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA.
| | - Zhangjun Fei
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA.
- United States Department of Agriculture, Agricultural Research Service, Robert W. Holley Center for Agriculture and Health, Ithaca, NY, 14853, USA.
| | - Gan-Yuan Zhong
- United States Department of Agriculture, Agricultural Research Service, Grape Genetics Research Unit, Geneva, NY, 14456, USA.
| |
Collapse
|
26
|
Abdellatef E, Will T, Koch A, Imani J, Vilcinskas A, Kogel KH. Silencing the expression of the salivary sheath protein causes transgenerational feeding suppression in the aphid Sitobion avenae. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:849-57. [PMID: 25586210 DOI: 10.1111/pbi.12322] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/07/2014] [Accepted: 12/04/2014] [Indexed: 05/24/2023]
Abstract
Aphids produce gel saliva during feeding which forms a sheath around the stylet as it penetrates through the apoplast. The sheath is required for the sustained ingestion of phloem sap from sieve elements and is thought to form when the structural sheath protein (SHP) is cross-linked by intermolecular disulphide bridges. We investigated the possibility of controlling aphid infestation by host-induced gene silencing (HIGS) targeting shp expression in the grain aphid Sitobion avenae. When aphids were fed on transgenic barley expressing shp double-stranded RNA (shp-dsRNA), they produced significantly lower levels of shp mRNA compared to aphids feeding on wild-type plants, suggesting that the transfer of inhibitory RNA from the plant to the insect was successful. shp expression remained low when aphids were transferred from transgenic plants and fed for 1 or 2 weeks, respectively, on wild-type plants, confirming that silencing had a prolonged impact. Reduced shp expression correlated with a decline in growth, reproduction and survival rates. Remarkably, morphological and physiological aberrations such as winged adults and delayed maturation were maintained over seven aphid generations feeding on wild-type plants. Targeting shp expression therefore appears to cause strong transgenerational effects on feeding, development and survival in S. avenae, suggesting that the HIGS technology has a realistic potential for the control of aphid pests in agriculture.
Collapse
Affiliation(s)
- Eltayb Abdellatef
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
| | - Torsten Will
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
| | - Aline Koch
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
| | - Jafargholi Imani
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
| | - Andreas Vilcinskas
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
- Project Group 'Bioresources', Fraunhofer Institute of Molecular Biology and Applied Ecology IME, Giessen, Germany
| | - Karl-Heinz Kogel
- Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus Liebig University, Giessen, Germany
| |
Collapse
|
27
|
Furch ACU, van Bel AJE, Will T. Aphid salivary proteases are capable of degrading sieve-tube proteins. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:533-9. [PMID: 25540441 DOI: 10.1093/jxb/eru487] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Sieve tubes serve as transport conduits for photo-assimilates and other resources in angiosperms and are profitable targets for piercing-sucking insects such as aphids. Sieve-tube sap also contains significant amounts of proteins with diverse functions, for example in signalling, metabolism, and defence. The identification of salivary proteases in Acyrthosiphon pisum led to the hypothesis that aphids might be able to digest these proteins and by doing so suppress plant defence and access additional nitrogen sources. Here, the scarce knowledge of proteases in aphid saliva is briefly reviewed. In order to provide a better platform for discussion, we conducted a few tests on in vitro protease activity and degradation of sieve-tube sap proteins of Cucurbita maxima by watery saliva. Inhibition of protein degradation by EDTA indicates the presence of different types of proteases (e.g. metalloproteses) in saliva of A. pisum. Proteases in the watery saliva from Macrosiphum euphorbiae and A. pisum were able to degrade the most abundant phloem protein, which is phloem protein 1. Our results provide support for the breakdown of sieve-element proteins by aphid saliva in order to suppress/neutralize the defence responses of the plant and to make proteins of sieve-tube sap accessible as a nitrogen source, as is discussed in detail. Finally, we discuss whether glycosylation of sieve-element proteins and the presence of protease inhibitors may confer partial protection against the proteolytic activity of aphid saliva.
Collapse
Affiliation(s)
- Alexandra C U Furch
- Institute of General Botany and Plant Physiology, Friedrich-Schiller-University, Dornburger Str. 159, D-07743 Jena, Germany
| | - Aart J E van Bel
- Department of General Botany, Justus-Liebig-University, Heinrich-Buff-Ring 17, D-35392 Giessen, Germany
| | - Torsten Will
- Institute of Phytopathology and Applied Zoology, Centre for BioSystems, Land Use and Nutrition, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
| |
Collapse
|
28
|
Guan W, Ferry N, Edwards MG, Bell HA, Othman H, Gatehouse JA, Gatehouse AMR. Proteomic analysis shows that stress response proteins are significantly up-regulated in resistant diploid wheat ( Triticum monococcum) in response to attack by the grain aphid ( Sitobion avenae). MOLECULAR BREEDING : NEW STRATEGIES IN PLANT IMPROVEMENT 2015; 35:57. [PMID: 25642140 PMCID: PMC4308650 DOI: 10.1007/s11032-015-0220-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Accepted: 11/27/2014] [Indexed: 05/24/2023]
Abstract
The grain aphid Sitobion avenae (F.) is a major pest of wheat, acting as a virus vector as well as causing direct plant damage. Commonly grown wheat varieties in the UK have only limited resistance to this pest. The present study was carried out to investigate the potential of a diploid wheat line (ACC20 PGR1755), reported as exhibiting resistance to S. avenae, to serve as a source of resistance genes. The diploid wheat line was confirmed as partially resistant, substantially reducing the fecundity, longevity and growth rate of the aphid. Proteomic analysis showed that approximately 200 protein spots were reproducibly detected in leaf extracts from both the resistant line and a comparable susceptible line (ACC5 PGR1735) using two-dimensional gel electrophoresis and image comparison software. Twenty-four spots were significantly up-regulated (>2-fold) in the resistant line after 24 h of aphid feeding (13 and 11 involved in local and systemic responses, respectively). Approximately 50 % of all differentially expressed protein spots were identified by a combination of database searching with MS and MS/MS data, revealing that the majority of proteins up-regulated by aphid infestation were involved in metabolic processes (including photosynthesis) and transcriptional regulation. However, in the resistant line only, several stress response proteins (including NBS-LRR-like proteins) and oxidative stress response proteins were identified as up-regulated in response to aphid feeding, as well as proteins involved in DNA synthesis/replication/repair. This study indicates that the resistant diploid line ACC20 PGR1755 may provide a valuable resource in breeding wheat for resistance to aphids.
Collapse
Affiliation(s)
- Wenzhu Guan
- Newcastle Institute for Research on Sustainability, School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - Natalie Ferry
- Newcastle Institute for Research on Sustainability, School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
- School of Environment and Life Science, Salford University, Salford, M5 4WT UK
| | - Martin G. Edwards
- Newcastle Institute for Research on Sustainability, School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - Howard A. Bell
- The Food and Environment Research Agency, Sand Hutton, York, YO41 1LZ UK
| | - Hamizah Othman
- Newcastle Institute for Research on Sustainability, School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| | - John A. Gatehouse
- School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK
| | - Angharad M. R. Gatehouse
- Newcastle Institute for Research on Sustainability, School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU UK
| |
Collapse
|
29
|
Notaguchi M. Identification of phloem-mobile mRNA. JOURNAL OF PLANT RESEARCH 2015; 128:27-35. [PMID: 25516498 DOI: 10.1007/s10265-014-0675-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 10/06/2014] [Indexed: 05/07/2023]
Abstract
Signaling between cells, tissues and organs is essential for multicellular organisms to coordinate and adapt their development and growth to internal and environmental changes. Plants have evolved a plant-specific symplasmic pathway, called plasmodesmata, for efficient intercellular communication, in addition to the receptor-ligand-based apoplasmic pathway. Long-distance signaling between distant organs is enabled via the phloem tube system, where plasmodesmata contribute to phloem loading and unloading for photosynthate allocation. In addition to signaling by small molecules such as metabolites and phytohormones, the transport of proteins, small RNAs and mRNAs is also considered an important mechanism to achieve long-distance signaling in plants. Recent studies on phloem-mobile proteins and small RNAs have revealed their role in crucial physiological processes including flowering, systemic silencing and nutrient allocation. However, the biological role of mRNAs found in the phloem tube is not yet clear, though their mobility over long-distances has been well evidenced. To gain this knowledge, it is important to collect further information on mRNA profiles in the phloem translocation stream. In this review, I summarize the current approaches to identifying the mRNA population in the phloem translocation system, and discuss the possible role of short- and long-distance mRNA transport.
Collapse
Affiliation(s)
- Michitaka Notaguchi
- Graduate School of Science, Nagoya University, B-105, Bldg B, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan,
| |
Collapse
|
30
|
Kuhlmann F, Opitz SEW, Inselsbacher E, Ganeteg U, Näsholm T, Ninkovic V. Exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15)N labelling. PLoS One 2014; 8:e83085. [PMID: 24376642 PMCID: PMC3871520 DOI: 10.1371/journal.pone.0083085] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 10/30/2013] [Indexed: 12/05/2022] Open
Abstract
Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen (15N). We combined the Electrical Penetration Graph (EPG) technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS) to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae) fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae) that were cultivated with a 15N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their 15N uptake. All other single behavioural phases were not correlated with 15N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and 15N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed.
Collapse
Affiliation(s)
- Franziska Kuhlmann
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | | | - Erich Inselsbacher
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Ulrika Ganeteg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Velemir Ninkovic
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
- * E-mail:
| |
Collapse
|
31
|
Tetyuk O, Benning UF, Hoffmann-Benning S. Collection and analysis of Arabidopsis phloem exudates using the EDTA-facilitated Method. J Vis Exp 2013:e51111. [PMID: 24192764 PMCID: PMC3960974 DOI: 10.3791/51111] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The plant phloem is essential for the long-distance transport of (photo-) assimilates as well as of signals conveying biotic or abiotic stress. It contains sugars, amino acids, proteins, RNA, lipids and other metabolites. While there is a large interest in understanding the composition and function of the phloem, the role of many of these molecules and thus, their importance in plant development and stress response has yet to be determined. One barrier to phloem analysis lies in the fact that the phloem seals itself upon wounding. As a result, the number of plants from which phloem sap can be obtained is limited. One method that allows collection of phloem exudates from several plant species without added equipment is the EDTA-facilitated phloem exudate collection described here. While it is easy to use, it does lead to the wounding of cells and care has to be taken to remove contents of damaged cells. In addition, several controls to prove purity of the exudate are necessary. Because it is an exudation rather than a direct collection of the phloem sap (not possible in many species) only relative quantification of its contents can occur. The advantage of this method over others is that it can be used in many herbaceous or woody plant species (Perilla, Arabidopsis, poplar, etc.) and requires minimal equipment and training. It leads to reasonably large amounts of exudates that can be used for subsequent analysis of proteins, sugars, lipids, RNA, viruses and metabolites. It is simple enough that it can be used in both a research as well as in a teaching laboratory.
Collapse
Affiliation(s)
- Olena Tetyuk
- Biochemistry and Molecular Biology, Michigan State Universtiy
| | | | | |
Collapse
|
32
|
Palmer LJ, Palmer LT, Pritchard J, Graham RD, Stangoulis JCR. Improved techniques for measurement of nanolitre volumes of phloem exudate from aphid stylectomy. PLANT METHODS 2013; 9:18. [PMID: 23773489 PMCID: PMC3693976 DOI: 10.1186/1746-4811-9-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/13/2013] [Indexed: 05/24/2023]
Abstract
BACKGROUND When conducting aphid stylectomy, measuring accurate rates of phloem exudation is difficult because the volumes collected are in the nanolitre (nl) range. In a new method, exudate volume was calculated from optical measurement of droplet diameter as it forms on the tip of a severed aphid stylet. Evaporation was shown to decrease the accuracy of the measurement but was countered with the addition of water-saturated mineral oil. Volume measurements by optical estimation of the volume of a sphere suspended in oil was affected by the curvature of the oil surface. In contrast, measuring the exudate volume from optical measurement of droplet-diameter as formed on the tip of a severed aphid stylet, removes any inaccuracies due to oil surface curvature. A modified technique is proposed for measuring exudate volumes without oil by estimating the flow rate from photo-sequences of the collection period; a correction for evaporation is applied later. RESULTS A change in oil volume of ±1.75% from an optimum volume of 285 μl had a statistically significant effect on droplet measurement, under or over-estimating droplet volume due to optical effects caused by the oil surface. Using microscope image capture and measurement software, a modified method for measuring phloem volume in air was developed, by reducing air exposure during measurement to approximately 5 s for each measurement. Phloem volumes were measured using both techniques with measurements in air being on average 19.9 nl less (SD 18.87, p<0.001) than those made in oil, and there was a strong linear relationship (R(2)=0.942) between the techniques. This linear relationship enabled the development of a correction equation with no significant difference at the 5% level between corrected volumes and actual volumes measured under oil. CONCLUSIONS This study showed that oil has a significant role in countering evaporation but oil volume must be carefully optimised for optical measurement of droplets to ensure measurement accuracy. A linear correction factor was generated to correct the volumes measured in air for loss due to evaporation and the method provides for a much simpler alternative to previous approaches for measuring exudation rates and volumes from a cut aphid stylet.
Collapse
Affiliation(s)
- Lachlan J Palmer
- School of Biological Science, Flinders University, 5042 Bedford Park, South Australia, Australia
| | - Lyndon T Palmer
- School of Agriculture Food and Wine, University of Adelaide, Waite Campus, 5064 Adelaide, South Australia, Australia
| | - Jeremy Pritchard
- School of Biosciences, University of Birmingham, Edgbaston, B152TT Birmingham, UK
| | - Robin D Graham
- School of Biological Science, Flinders University, 5042 Bedford Park, South Australia, Australia
| | - James CR Stangoulis
- School of Biological Science, Flinders University, 5042 Bedford Park, South Australia, Australia
| |
Collapse
|
33
|
Lucas WJ, Groover A, Lichtenberger R, Furuta K, Yadav SR, Helariutta Y, He XQ, Fukuda H, Kang J, Brady SM, Patrick JW, Sperry J, Yoshida A, López-Millán AF, Grusak MA, Kachroo P. The plant vascular system: evolution, development and functions. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:294-388. [PMID: 23462277 DOI: 10.1111/jipb.12041] [Citation(s) in RCA: 400] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essential functions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.
Collapse
Affiliation(s)
- William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Lin T, Sharma P, Gonzalez DH, Viola IL, Hannapel DJ. The impact of the long-distance transport of a BEL1-like messenger RNA on development. PLANT PHYSIOLOGY 2013; 161:760-72. [PMID: 23221774 PMCID: PMC3561017 DOI: 10.1104/pp.112.209429] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 11/30/2012] [Indexed: 05/18/2023]
Abstract
BEL1- and KNOTTED1-type proteins are transcription factors from the three-amino-loop-extension superclass that interact in a tandem complex to regulate the expression of target genes. In potato (Solanum tuberosum), StBEL5 and its Knox protein partner regulate tuberization by targeting genes that control growth. RNA movement assays demonstrated that StBEL5 transcripts move through the phloem to stolon tips, the site of tuber induction. StBEL5 messenger RNA originates in the leaf, and its movement to stolons is induced by a short-day photoperiod. Here, we report the movement of StBEL5 RNA to roots correlated with increased growth, changes in morphology, and accumulation of GA2-oxidase1, YUCCA1a, and ISOPENTENYL TRANSFERASE transcripts. Transcription of StBEL5 in leaves is induced by light but insensitive to photoperiod, whereas in stolon tips growing in the dark, promoter activity is enhanced by short days. The heterodimer of StBEL5 and POTH1, a KNOTTED1-type transcription factor, binds to a tandem TTGAC-TTGAC motif that is essential for regulating transcription. The discovery of an inverted tandem motif in the StBEL5 promoter with TTGAC motifs on opposite strands may explain the induction of StBEL5 promoter activity in stolon tips under short days. Using transgenic potato lines, deletion of one of the TTGAC motifs from the StBEL5 promoter results in the reduction of GUS activity in new tubers and roots. Gel-shift assays demonstrate BEL5/POTH1 binding specificity to the motifs present in the StBEL5 promoter and a double tandem motif present in the StGA2-oxidase1 promoter. These results suggest that, in addition to tuberization, the movement of StBEL5 messenger RNA regulates other aspects of vegetative development.
Collapse
|
35
|
Dinant S, Kehr J. Sampling and analysis of phloem sap. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2013; 953:185-94. [PMID: 23073884 DOI: 10.1007/978-1-62703-152-3_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The transport tubes of the phloem are essential for higher plants. They not only provide the route for the distribution of assimilates produced during photosynthesis from source to sink organs but also (re-) distribute mineral nutrients. Additionally, the phloem is essential for sending information between distant plant organs and steering developmental and defense processes. For example, flowering and tuberization time are controlled by phloem-mobile signals and important defense reactions on the whole plant level, like systemic acquired resistance or systemic gene silencing, are spread through the phloem. In addition, recent results demonstrate that also the allocation of mineral nutrients is coordinated by phloem mobile signaling molecules. However, in many studies the important analysis of phloem sap is neglected, probably because the content of sieve tubes is not easy to access. This chapter will describe the current methods for sampling and analysis of phloem sap in order to encourage researchers to include the analysis of this crucial compartment in their relevant studies.
Collapse
Affiliation(s)
- Sylvie Dinant
- Institut Jean Pierre Bourgin (IJPB), INRA-AgroParisTech, Versailles, France
| | | |
Collapse
|
36
|
Gaupels F, Sarioglu H, Beckmann M, Hause B, Spannagl M, Draper J, Lindermayr C, Durner J. Deciphering systemic wound responses of the pumpkin extrafascicular phloem by metabolomics and stable isotope-coded protein labeling. PLANT PHYSIOLOGY 2012; 160:2285-99. [PMID: 23085839 PMCID: PMC3510148 DOI: 10.1104/pp.112.205336] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/18/2012] [Indexed: 05/22/2023]
Abstract
In cucurbits, phloem latex exudes from cut sieve tubes of the extrafascicular phloem (EFP), serving in defense against herbivores. We analyzed inducible defense mechanisms in the EFP of pumpkin (Cucurbita maxima) after leaf damage. As an early systemic response, wounding elicited transient accumulation of jasmonates and a decrease in exudation probably due to partial sieve tube occlusion by callose. The energy status of the EFP was enhanced as indicated by increased levels of ATP, phosphate, and intermediates of the citric acid cycle. Gas chromatography coupled to mass spectrometry also revealed that sucrose transport, gluconeogenesis/glycolysis, and amino acid metabolism were up-regulated after wounding. Combining ProteoMiner technology for the enrichment of low-abundance proteins with stable isotope-coded protein labeling, we identified 51 wound-regulated phloem proteins. Two Sucrose-Nonfermenting1-related protein kinases and a 32-kD 14-3-3 protein are candidate central regulators of stress metabolism in the EFP. Other proteins, such as the Silverleaf Whitefly-Induced Protein1, Mitogen Activated Protein Kinase6, and Heat Shock Protein81, have known defensive functions. Isotope-coded protein labeling and western-blot analyses indicated that Cyclophilin18 is a reliable marker for stress responses of the EFP. As a hint toward the induction of redox signaling, we have observed delayed oxidation-triggered polymerization of the major Phloem Protein1 (PP1) and PP2, which correlated with a decline in carbonylation of PP2. In sum, wounding triggered transient sieve tube occlusion, enhanced energy metabolism, and accumulation of defense-related proteins in the pumpkin EFP. The systemic wound response was mediated by jasmonate and redox signaling.
Collapse
Affiliation(s)
- Frank Gaupels
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, D-85764 Neuherberg, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Marín-González E, Suárez-López P. "And yet it moves": cell-to-cell and long-distance signaling by plant microRNAs. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 196:18-30. [PMID: 23017896 DOI: 10.1016/j.plantsci.2012.07.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 07/17/2012] [Accepted: 07/21/2012] [Indexed: 05/07/2023]
Abstract
MicroRNAs (miRNAs) are key regulators of numerous genes in many eukaryotes. Some plant miRNAs are involved in developmental and physiological processes that require intercellular or inter-organ signaling. Movement of other small RNAs within plants has been established. Recent findings also demonstrate intercellular signaling by miRNAs and strongly support that a subset of these regulatory molecules move from one cell to another or over long distances. Phloem exudates contain diverse miRNAs and at least two of them, involved in responses to nutrient availability, are transmitted through grafts, indicating long-distance movement. Two miRNAs that regulate developmental processes are present in cells outside their domains of expression. Several results strongly support that one of them moves from cell to cell. Research on a mutant affected in plasmodesmata trafficking indicates that these intercellular channels are required for transmission of miRNA activity to adjacent cells. Moreover, ARGONAUTE proteins might be involved in the regulation of miRNA trafficking. Hypothesis on the features and mechanisms that may determine miRNA mobility are presented. Future challenges include identifying other mobile miRNAs; demonstrating that miRNA movement is required for non-cell autonomous action; and characterizing the mechanisms of translocation and genetic pathways that regulate miRNA movement.
Collapse
Affiliation(s)
- Esther Marín-González
- Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB, Campus UAB, Edifici CRAG, Bellaterra-Cerdanyola del Vallès, 08193 Barcelona, Spain
| | | |
Collapse
|
38
|
Tufan HA, McGrann GRD, MacCormack R, Boyd LA. TaWIR1 contributes to post-penetration resistance to Magnaporthe oryzae, but not Blumeria graminis f. sp. tritici, in wheat. MOLECULAR PLANT PATHOLOGY 2012; 13:653-65. [PMID: 22243838 PMCID: PMC6638694 DOI: 10.1111/j.1364-3703.2011.00775.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Members of the Wheat-Induced Resistance 1 (TaWIR1) gene family are highly induced in response to a wide range of pathogens. Homologues have been identified in barley, but not in Brachypodium, whereas, in rice, only distant WIR1 candidates are known. Phylogenetic analysis placed TaWIR1a and TaWIR1b within a distinct clade of wheat transcripts, whereas TaWIR1c clustered with HvWIR1 genes. Transcripts of all three TaWIR1 genes were strongly induced by a wheat-adapted isolate of Magnaporthe oryzae. Virus-induced gene silencing of the TaWIR1 gene family had no effect on the initial penetration of epidermal cells by M. oryzae. However, following the establishment of an infection site, the fungus was able to grow more extensively within the leaf tissue, relative to control leaves, indicating a role for the TaWIR1 gene family in the cell-to-cell movement of M. oryzae. In contrast, the silencing of TaWIR1 transcripts had no effect on epidermal cell penetration by a wheat-adapted isolate of Blumeria graminis, or on the subsequent growth of hyphae. Differential transcription of TaWIR1 genes was also seen in epidermal peels, relative to the remaining leaf tissue, following inoculation with M. oryzae.
Collapse
Affiliation(s)
- Hale A Tufan
- Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | | | | |
Collapse
|
39
|
Wang SS, Liu ZZ, Sun C, Shi QH, Yao YX, You CX, Hao YJ. Functional characterization of the apple MhGAI1 gene through ectopic expression and grafting experiments in tomatoes. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:303-10. [PMID: 22153898 DOI: 10.1016/j.jplph.2011.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 09/19/2011] [Accepted: 09/21/2011] [Indexed: 05/07/2023]
Abstract
DELLA proteins are essential components of GA signal transduction. MhGAI1 was isolated from the tea crabapple (Malus hupehensis Redh. var. pingyiensis), and it was found to encode a DELLA protein. Mhgai1 is a GA-insensitive allele that was artificially generated via a bridge-PCR approach. Ectopic expression of Mhgai1 reduced plant stature, decreased spontaneous fruit-set-ratio and enhanced drought-tolerance in transgenic tomatoes. In addition, we examined the long-distance movement of Mhgai1 mRNAs by grafting experiments and SqRT-PCR analysis. It was found that the wild-type scions accumulated Mhgai1 transcripts trafficked from the transgenic rootstocks and therefore exhibited dwarf phenotypes. Furthermore, transgenic tomato plants produced more soluble solids, sugars and organic acids compared to wild-type tomatoes, suggesting an involvement of GA signaling in the regulation of fruit quality. Despite noticeable accumulation in the leaves and stems of WT scions, Mhgai1 transcripts were undetectable in flowers and fruit. Therefore, fruit quality was less influenced by the grafting of WT scions onto transgenic rootstocks than they were by the ectopic expression of Mhgai1 in transgenic rootstocks. Taken together, MhGAI1, which functions as a repressor in the GA signaling pathway, and its GA-insensitive allele, Mhgai1, could turn out to be useful targets for the genetic improvement of dwarfing rootstocks in apples.
Collapse
Affiliation(s)
- Shuang-Shuang Wang
- State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | | | | | | | | | | | | |
Collapse
|
40
|
Ruiz-Medrano R, Xoconostle-Cázares B, Ham BK, Li G, Lucas WJ. Vascular expression in Arabidopsis is predicted by the frequency of CT/GA-rich repeats in gene promoters. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:130-44. [PMID: 21435051 DOI: 10.1111/j.1365-313x.2011.04581.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Phloem-transported signals play an important role in regulating plant development and in orchestrating responses to environmental stimuli. Among such signals, phloem-mobile RNAs have been shown to play an important role as long-distance signaling agents. At maturity, angiosperm sieve elements are enucleate, and thus transcripts in the phloem translocation stream probably originate from the nucleate companion cells. In the present study, a pumpkin (Cucurbita maxima) phloem transcriptome was used to test for the presence of common motifs within the promoters of this unique set of genes, which may function to coordinate expression in cells of the vascular system. A bioinformatics analysis of the upstream sequences from 150 Arabidopsis genes homologous to members of the pumpkin phloem transcriptome identified degenerate sequences containing CT/GA- and GT/CA-rich motifs that were common to many of these promoters. Parallel studies performed on genes shown previously to be expressed in phloem tissues identified similar motifs. An expanded analysis, based on homologs of the pumpkin phloem transcriptome from cucumber (Cucumis sativus), identified similar sets of common motifs within the promoters of these genes. Promoter analysis offered support for the hypothesis that these motifs regulate expression within the vascular system. Our findings are discussed in terms of a role for these motifs in coordinating gene expression within the companion cell/sieve element system. These motifs could provide a useful bioinformatics tool for genome-wide screens on plants for which phloem tissues cannot readily be obtained.
Collapse
Affiliation(s)
- Roberto Ruiz-Medrano
- Department of Biotechnology and Bioengineering, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Avenida IPN 2508, Zacatenco, 07360 Mexico DF, Mexico
| | | | | | | | | |
Collapse
|
41
|
Pyati P, Bandani AR, Fitches E, Gatehouse JA. Protein digestion in cereal aphids (Sitobion avenae) as a target for plant defence by endogenous proteinase inhibitors. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:881-91. [PMID: 21477592 DOI: 10.1016/j.jinsphys.2011.03.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 03/24/2011] [Accepted: 03/25/2011] [Indexed: 05/21/2023]
Abstract
Gut extracts from cereal aphids (Sitobion avenae) showed significant levels of proteolytic activity, which was inhibited by reagents specific for cysteine proteases and chymotrypsin-like proteases. Gut tissue contained cDNAs encoding cathepsin B-like cysteine proteinases, similar to those identified in the closely related pea aphid (Acyrthosiphon pisum). Analysis of honeydew (liquid excreta) from cereal aphids fed on diet containing ovalbumin showed that digestion of ingested proteins occurred in vivo. Protein could partially substitute for free amino acids in diet, although it could not support complete development. Recombinant wheat proteinase inhibitors (PIs) fed in diet were antimetabolic to cereal aphids, even when normal levels of free amino acids were present. PIs inhibited proteolysis by aphid gut extracts in vitro, and digestion of protein fed to aphids in vivo. Wheat subtilisin/chymotrypsin inhibitor, which was found to inhibit serine and cysteine proteinases, was more effective in both inhibitory and antimetabolic activity than wheat cystatin, which inhibited cysteine proteases only. Digestion of ingested protein is unlikely to contribute significantly to nutritional requirements when aphids are feeding on phloem, and the antimetabolic activity of dietary proteinase inhibitors is suggested to result from effects on proteinases involved in degradation of endogenous proteins.
Collapse
Affiliation(s)
- Prashant Pyati
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | | | | | | |
Collapse
|
42
|
Ion uptake and structural modifications induced by nitrogen source in tomato (Solanum lycopersicum Mill. Cv. Ibiza F1). C R Biol 2011; 334:526-34. [DOI: 10.1016/j.crvi.2011.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 02/22/2011] [Accepted: 05/04/2011] [Indexed: 11/16/2022]
|
43
|
Rodriguez-Medina C, Atkins CA, Mann AJ, Jordan ME, Smith PMC. Macromolecular composition of phloem exudate from white lupin (Lupinus albus L.). BMC PLANT BIOLOGY 2011; 11:36. [PMID: 21342527 PMCID: PMC3055823 DOI: 10.1186/1471-2229-11-36] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 02/22/2011] [Indexed: 05/17/2023]
Abstract
BACKGROUND Members of the legume genus Lupinus exude phloem 'spontaneously' from incisions made to the vasculature. This feature was exploited to document macromolecules present in exudate of white lupin (Lupinus albus [L.] cv Kiev mutant), in particular to identify proteins and RNA molecules, including microRNA (miRNA). RESULTS Proteomic analysis tentatively identified 86 proteins from 130 spots collected from 2D gels analysed by partial amino acid sequence determination using MS/MS. Analysis of a cDNA library constructed from exudate identified 609 unique transcripts. Both proteins and transcripts were classified into functional groups. The largest group of proteins comprised those involved in metabolism (24%), followed by protein modification/turnover (9%), redox regulation (8%), cell structural components (6%), stress and defence response (6%) with fewer in other groups. More prominent proteins were cyclophilin, ubiquitin, a glycine-rich RNA-binding protein, a group of proteins that comprise a glutathione/ascorbate-based mechanism to scavenge oxygen radicals, enzymes of glycolysis and other metabolism including methionine and ethylene synthesis. Potential signalling macromolecules such as transcripts encoding proteins mediating calcium level and the Flowering locus T (FT) protein were also identified. From around 330 small RNA clones (18-25 nt) 12 were identified as probable miRNAs by homology with those from other species. miRNA composition of exudate varied with site of collection (e.g. upward versus downward translocation streams) and nutrition (e.g. phosphorus level). CONCLUSIONS This is the first inventory of macromolecule composition of phloem exudate from a species in the Fabaceae, providing a basis to identify systemic signalling macromolecules with potential roles in regulating development, growth and stress response of legumes.
Collapse
Affiliation(s)
- Caren Rodriguez-Medina
- INRA Center Colmar. France
- School of Plant Biology, The University of Western Australia, Crawley. WA 6009. Australia
- School of Biological Science, The University of Sydney. NSW 2006. Australia
| | - Craig A Atkins
- School of Plant Biology, The University of Western Australia, Crawley. WA 6009. Australia
| | - Anthea J Mann
- School of Plant Biology, The University of Western Australia, Crawley. WA 6009. Australia
| | - Megan E Jordan
- School of Plant Biology, The University of Western Australia, Crawley. WA 6009. Australia
| | - Penelope MC Smith
- School of Biological Science, The University of Sydney. NSW 2006. Australia
| |
Collapse
|
44
|
Atkins CA, Smith PMC, Rodriguez-Medina C. Macromolecules in phloem exudates--a review. PROTOPLASMA 2011; 248:165-72. [PMID: 21057827 DOI: 10.1007/s00709-010-0236-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Accepted: 10/26/2010] [Indexed: 05/02/2023]
Abstract
Proteomic and transcriptomic analyses using the growing resources of genomic information have been applied to identification of macromolecules in exudates collected from phloem. Most of the analyses rely on collection of exudate following incisions made to the vasculature, but some limited data are available for exudates collected from excised aphid stylets. Species examined, to date, include a number of cereals (rice, barley, and wheat), a number of cucurbits, castor bean, members of the genus Lupinus, brassicas, and Arabidopsis. As many as 1,100 proteins, some hundreds of transcripts, and a growing number of small ribonucleic acids (RNAs), including micro-RNAs, have been identified across the species with a high degree of commonality. Questions relating to the nature and extent of contamination of sieve element contents with those of surrounding companion cells and nonvascular cells are addressed together with likely functions of identified macromolecules. The review considers likely translocation and systemic signaling functions among the macromolecular inventory of phloem exudates.
Collapse
Affiliation(s)
- Craig A Atkins
- School of Plant Biology, University of Western Australia, Crawley, WA, 6009, Australia.
| | | | | |
Collapse
|
45
|
Jan NE, Kawabata S. Relationship between Fruit Soluble Solid Content and the Sucrose Concentration of the Phloem Sap at Different Leaf to Fruit Ratios in Tomato. ACTA ACUST UNITED AC 2011. [DOI: 10.2503/jjshs1.80.314] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
46
|
Douchkov D, Johrde A, Nowara D, Himmelbach A, Lueck S, Niks R, Schweizer P. Convergent evidence for a role of WIR1 proteins during the interaction of barley with the powdery mildew fungus Blumeria graminis. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:20-29. [PMID: 20709427 DOI: 10.1016/j.jplph.2010.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 06/17/2010] [Accepted: 07/15/2010] [Indexed: 05/29/2023]
Abstract
Pathogen attack triggers a multifaceted defence response in plants that includes the accumulation of pathogenesis-related proteins and their corresponding transcripts. One of these transcripts encodes for WIR1, a small glycine- and proline-rich protein of unknown function that appears to be specific to grass species. Here we describe members of the HvWIR1 multigene family of barley with respect to phylogenetic relationship, transcript regulation, co-localization with quantitative trait loci for resistance to the barley powdery mildew fungus Blumeria graminis (DC.) E.O. Speer f.sp. hordei, the association of single nucleotide polymorphisms or gene haplotypes with resistance, as well as phenotypic effects of gene silencing by RNAi. HvWIR1 is encoded by a multigene family of moderate complexity that splits up into two major clades, one of those being also represented by previously described cDNA sequences from wheat. All analysed WIR1 transcripts accumulated in response to powdery mildew attack in leaves and all mapped WIR1 genes were associated with quantitative trait loci for resistance to B. graminis. Moreover, single nucleotide polymorphisms or haplotypes of WIR1 members were associated with quantitative resistance of barley to B. graminis, and transient WIR1 gene silencing affected the interaction of epidermal cells with the pathogen. The presented data provide convergent evidence for a role of the HvWIR1a gene and possibly other family members, during the interaction of barley with B. graminis.
Collapse
Affiliation(s)
- Dimitar Douchkov
- Leibniz-Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, Gatersleben, Germany
| | | | | | | | | | | | | |
Collapse
|
47
|
Varkonyi-Gasic E, Gould N, Sandanayaka M, Sutherland P, MacDiarmid RM. Characterisation of microRNAs from apple (Malus domestica 'Royal Gala') vascular tissue and phloem sap. BMC PLANT BIOLOGY 2010. [PMID: 20682080 DOI: 10.1186/1471-222910-159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND Plant microRNAs (miRNAs) are a class of small, non-coding RNAs that play an important role in development and environmental responses. Hundreds of plant miRNAs have been identified to date, mainly from the model species for which there are available genome sequences. The current challenge is to characterise miRNAs from plant species with agricultural and horticultural importance, to aid our understanding of important regulatory mechanisms in crop species and enable improvement of crops and rootstocks. RESULTS Based on the knowledge that many miRNAs occur in large gene families and are highly conserved among distantly related species, we analysed expression of twenty-one miRNA sequences in different tissues of apple (Malus x domestica 'Royal Gala'). We identified eighteen sequences that are expressed in at least one of the tissues tested. Some, but not all, miRNAs expressed in apple tissues including the phloem tissue were also detected in the phloem sap sample derived from the stylets of woolly apple aphids. Most of the miRNAs detected in apple phloem sap were also abundant in the phloem sap of herbaceous species. Potential targets for apple miRNAs were identified that encode putative proteins shown to be targets of corresponding miRNAs in a number of plant species. Expression patterns of potential targets were analysed and correlated with expression of corresponding miRNAs. CONCLUSIONS This study validated tissue-specific expression of apple miRNAs that target genes responsible for plant growth, development, and stress response. A subset of characterised miRNAs was also present in the apple phloem translocation stream. A comparative analysis of phloem miRNAs in herbaceous species and woody perennials will aid our understanding of non-cell autonomous roles of miRNAs in plants.
Collapse
Affiliation(s)
- Erika Varkonyi-Gasic
- The New Zealand Institute for Plant & Food Research Limited, Plant & Food Research, Auckland Mail Centre, Mt Albert, Private Bag 92169, Auckland 1142, New Zealand.
| | | | | | | | | |
Collapse
|
48
|
Varkonyi-Gasic E, Gould N, Sandanayaka M, Sutherland P, MacDiarmid RM. Characterisation of microRNAs from apple (Malus domestica 'Royal Gala') vascular tissue and phloem sap. BMC PLANT BIOLOGY 2010; 10:159. [PMID: 20682080 PMCID: PMC3095296 DOI: 10.1186/1471-2229-10-159] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 08/04/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plant microRNAs (miRNAs) are a class of small, non-coding RNAs that play an important role in development and environmental responses. Hundreds of plant miRNAs have been identified to date, mainly from the model species for which there are available genome sequences. The current challenge is to characterise miRNAs from plant species with agricultural and horticultural importance, to aid our understanding of important regulatory mechanisms in crop species and enable improvement of crops and rootstocks. RESULTS Based on the knowledge that many miRNAs occur in large gene families and are highly conserved among distantly related species, we analysed expression of twenty-one miRNA sequences in different tissues of apple (Malus x domestica 'Royal Gala'). We identified eighteen sequences that are expressed in at least one of the tissues tested. Some, but not all, miRNAs expressed in apple tissues including the phloem tissue were also detected in the phloem sap sample derived from the stylets of woolly apple aphids. Most of the miRNAs detected in apple phloem sap were also abundant in the phloem sap of herbaceous species. Potential targets for apple miRNAs were identified that encode putative proteins shown to be targets of corresponding miRNAs in a number of plant species. Expression patterns of potential targets were analysed and correlated with expression of corresponding miRNAs. CONCLUSIONS This study validated tissue-specific expression of apple miRNAs that target genes responsible for plant growth, development, and stress response. A subset of characterised miRNAs was also present in the apple phloem translocation stream. A comparative analysis of phloem miRNAs in herbaceous species and woody perennials will aid our understanding of non-cell autonomous roles of miRNAs in plants.
Collapse
Affiliation(s)
- Erika Varkonyi-Gasic
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) Mt Albert, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Nick Gould
- Plant & Food Research Ruakura, Private Bag 3123, Waikato Mail Centre, Hamilton 3240, New Zealand
| | - Manoharie Sandanayaka
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) Mt Albert, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Paul Sutherland
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) Mt Albert, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Robin M MacDiarmid
- The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) Mt Albert, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| |
Collapse
|
49
|
Dinant S, Bonnemain JL, Girousse C, Kehr J. Phloem sap intricacy and interplay with aphid feeding. C R Biol 2010; 333:504-15. [PMID: 20541162 DOI: 10.1016/j.crvi.2010.03.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aphididae feed upon the plant sieve elements (SE), where they ingest sugars, nitrogen compounds and other nutrients. For ingestion, aphid stylets penetrate SE, and because of the high hydrostatic pressure in SE, phloem sap exudes out into the stylets. Severing stylets to sample phloem exudates (i.e. stylectomy) has been used extensively for the study of phloem contents. Alternative sampling techniques are spontaneous exudation upon wounding that only works in a few plant species, and the popular EDTA-facilitated exudation technique. These approaches have allowed fundamental advances on the understanding of phloem sap composition and sieve tube physiology, which are surveyed in this review. A more complete picture of metabolites, ions, proteins and RNAs present in phloem sap is now available, which has provided large evidence for the phloem role as a signalling network in addition to its primary role in partitioning of photo-assimilates. Thus, phloem sap sampling methods can have remarkable applications to analyse plant nutrition, physiology and defence responses. Since aphid behaviour is suspected to be affected by phloem sap quality, attempts to manipulate phloem sap content were recently undertaken based on deregulation in mutant plants of genes controlling amino acid or sugar content of phloem sap. This opens up new strategies to control aphid settlement on a plant host.
Collapse
Affiliation(s)
- Sylvie Dinant
- UMR 1318 INRA-AgroParisTech, institut Jean-Pierre-Bourgin, bâtiment 2, route de Saint-Cyr, Versailles, France.
| | | | | | | |
Collapse
|
50
|
Abstract
The phloem is a central actor in plant development and nutrition, providing nutrients and energy to sink organs and integrating interorgan communication. A comprehensive picture of the molecules trafficking in phloem sap is being made available, with recent surveys of proteins, RNAs, sugars, and other metabolites, some of which are potentially acting as signals. In this review, we focus on recent breakthroughs on phloem transport and signalling. A case study was phloem loading of sucrose, acting both as a nutrient and as a signal, whose activity was shown to be tightly regulated. Recent advances also described actors of macromolecular trafficking in sieve elements, including chaperones and RNA binding proteins, involved potentially in the formation of ribonucleoprotein complexes. Likewise, long distance signalling appeared to integrate electrical potential waves, calcium bursts and potentially the generation of reactive oxygen species. The ubiquitin-proteasome system was also proposed to be on action in sieve elements for signalling and protein turnover. Surprisingly, several basic processes of phloem physiology are still under debate. Hence, the absence in phloem sap of reducing sugar species, such as hexoses, was recently challenged with observations based on an analysis of the sap from Ranunculaceae and Papaveraceae. The possibility that protein synthesis might occur in sieve elements was again questioned with the identification of components of the translational machinery in Pumpkin phloem sap. Altogether, these new findings strengthen the idea that phloem is playing a central role in interorgan nutrient exchanges and communication and demonstrate that the ways by which this is achieved can obey various patterns among species.
Collapse
Affiliation(s)
- Sylvie Dinant
- Institut National de la Recherche Agronomique, institut Jean-Pierre-Bourgin, route de St-Cyr, Versailles cedex, France.
| | | |
Collapse
|