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Bio-protocol Mar 2020Intercellular communication plays a crucial role in the establishment of multicellular organisms by organizing and coordinating growth, development and defence...
Intercellular communication plays a crucial role in the establishment of multicellular organisms by organizing and coordinating growth, development and defence responses. In plants, cell-to-cell communication takes place through nanometric membrane channels called plasmodesmata (PD). Understanding how PD dictate cellular connectivity greatly depends on a comprehensive knowledge of the molecular composition and the functional characterization of PD components. While proteomic and genetic approaches have been crucial to identify PD-associated proteins, fluorescence microscopy combined with fluorescent protein tagging is equally crucial to visualise the subcellular localisation of a protein of interest and gain knowledge about their dynamic behaviour. In this protocol we describe in detail a robust method for quantifying the degree of association of a given protein with PD, through ratiometric fluorescent intensity using confocal microscopy. Although developed for and , this protocol can be adapted to other plant species.
PubMed: 33659519
DOI: 10.21769/BioProtoc.3545 -
Current Opinion in Plant Biology Dec 2021Fruit consumption is fundamental to a balanced diet. The contemporary challenge of maintaining a steady food supply to meet the demands of a growing population is... (Review)
Review
Fruit consumption is fundamental to a balanced diet. The contemporary challenge of maintaining a steady food supply to meet the demands of a growing population is driving the development of strategies to improve the production and nutritional quality of fruit. Plasmodesmata, the structures that mediate symplasmic transport between plant cells, play an important role in phloem unloading and distribution of sugars and signalling molecules into developing organs. Targeted modifications to the structures and functioning of plasmodesmata have the potential to improve fruit development; however, knowledge on the mechanisms underpinning plasmodesmata regulation in this context is scarce. In this review, we have compiled current knowledge on plasmodesmata and their structural characterisation during the development of fruit organs. We discuss key questions on phloem unloading, including the pathway shift from symplasmic to apoplastic that takes place during the onset of ripening as potential targets for improving fruit quality.
Topics: Biological Transport; Fruit; Phloem; Plasmodesmata; Sugars
PubMed: 34826657
DOI: 10.1016/j.pbi.2021.102145 -
Biology Open Nov 2020Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at... (Review)
Review
Auxin is an endogenous small molecule with an incredibly large impact on growth and development in plants. Movement of auxin between cells, due to its negative charge at most physiological pHs, strongly relies on families of active transporters. These proteins import auxin from the extracellular space or export it into the same. Mutations in these components have profound impacts on biological processes. Another transport route available to auxin, once the substance is inside the cell, are plasmodesmata connections. These small channels connect the cytoplasms of neighbouring plant cells and enable flow between them. Interestingly, the biological significance of this latter mode of transport is only recently starting to emerge with examples from roots, hypocotyls and leaves. The existence of two transport systems provides opportunities for reciprocal cross-regulation. Indeed, auxin levels influence proteins controlling plasmodesmata permeability, while cell-cell communication affects auxin biosynthesis and transport. In an evolutionary context, transporter driven cell-cell auxin movement and plasmodesmata seem to have evolved around the same time in the green lineage. This highlights a co-existence from early on and a likely functional specificity of the systems. Exploring more situations where auxin movement via plasmodesmata has relevance for plant growth and development, and clarifying the regulation of such transport, will be key aspects in coming years.This article has an associated Future Leader to Watch interview with the author of the paper.
Topics: Biological Transport; Cell Communication; Feedback, Physiological; Hydrogen-Ion Concentration; Indoleacetic Acids; Metabolic Networks and Pathways; Plant Cells; Plant Development; Plant Proteins; Plasmodesmata; Signal Transduction
PubMed: 33184092
DOI: 10.1242/bio.055541 -
Biochemistry. Biokhimiia May 2020Plasmodesmata (PD) are intercellular channels in plant tissues providing continuity of the cytoplasm, the plasma membrane (PM) and the endoplasmic reticulum (ER) of... (Review)
Review
Plasmodesmata (PD) are intercellular channels in plant tissues providing continuity of the cytoplasm, the plasma membrane (PM) and the endoplasmic reticulum (ER) of neighboring cells. These channels allow the active transport of macromolecules such as proteins or RNAs. Thus, PD are believed to play a critical role in the functional unity of plant tissues and the transport of signals required for plant development and responses to external stimuli. Recent findings indicate that the PD channel contains a specialized type of ER-PM membrane contact sites (MCSs), structural links formed between ER and PM with tethering proteins. As shown for animal cells, MCSs are essential for lipid and protein trafficking between ER and PM membranes as well as for stress responses or the maintenance of ER structural integrity. On the other hand, our knowledge of the PD-specific MCSs is still scarce, and experimentally supported models of organization of their structural elements are only starting to emerge. Here, we review the structural and functional properties of proteins that can take part in establishing MCSs in PD. We also discuss the significance of cytoskeleton, lipid membrane microdomains and cell wall components for the maintenance and remodeling of PD-specific MCS in response to various biotic and abiotic stresses.
Topics: Cell Membrane; Cell Wall; Cytoskeleton; Endoplasmic Reticulum; Membrane Microdomains; Microtubules; Plant Cells; Plasmodesmata; Protein Transport
PubMed: 32571183
DOI: 10.1134/S0006297920050028 -
Methods in Molecular Biology (Clifton,... 2022In plants, plasmodesmata (PD) are plasmamembrane-lined pores that traverse the cell wall to establish cytoplasmic and endomembrane continuity between neighboring cells....
In plants, plasmodesmata (PD) are plasmamembrane-lined pores that traverse the cell wall to establish cytoplasmic and endomembrane continuity between neighboring cells. As intercellular channels, PD play pivotal roles in plant growth and development, defense responses, and are also co-opted by viruses to spread cell-to-cell to establish systemic infection. Proteomic analyses of PD-enriched fractions may provide critical insights on plasmodesmal biology and PD-mediated virus-host interactions. However, it is difficult to isolate PD from plant tissues as they are firmly embedded in the cell wall. Here, we describe a protocol for the purification of PD from Nicotiana benthamiana leaves for proteomic analysis.
Topics: Cell Wall; Plants; Plasmodesmata; Proteomics; Nicotiana
PubMed: 34905196
DOI: 10.1007/978-1-0716-1835-6_12 -
Frontiers in Plant Science 2022Various species of small RNAs (sRNAs), notably microRNAs and small interfering RNAs (siRNAs), have been characterized as the major effectors of RNA interference in... (Review)
Review
Various species of small RNAs (sRNAs), notably microRNAs and small interfering RNAs (siRNAs), have been characterized as the major effectors of RNA interference in plants. Growing evidence supports a model in which sRNAs move, intercellularly, systemically, and between cross-species. These non-coding sRNAs can traffic cell-to-cell through plasmodesmata (PD), in a symplasmic manner, as well as from source to sink tissues, the phloem, to trigger gene silencing in their target cells. Such mobile sRNAs function in non-cell-autonomous communication pathways, to regulate various biological processes, such as plant development, reproduction, and plant defense. In this review, we summarize recent progress supporting the roles of mobile sRNA in plants, and discuss mechanisms of sRNA transport, signal amplification, and the plant's response, in terms of RNAi activity, within the recipient tissues. We also discuss potential research directions and their likely impact on engineering of crops with traits for achieving food security.
PubMed: 35783973
DOI: 10.3389/fpls.2022.928729 -
Journal of Experimental Botany May 2020The long-distance translocation of nutrients and mobile molecules between different terminals is necessary for plant growth and development. Plasmodesmata-mediated... (Review)
Review
The long-distance translocation of nutrients and mobile molecules between different terminals is necessary for plant growth and development. Plasmodesmata-mediated symplastic trafficking plays an important role in accomplishing this task. To facilitate intercellular transport, plants have evolved diverse plasmodesmata with distinct internal architecture at different cell-cell interfaces along the trafficking route. Correspondingly, different underlying mechanisms for regulating plasmodesmal structures have been gradually revealed. In this review, we highlight recent studies on various plasmodesmal architectures, as well as relevant regulators of their de novo formation and transition, responsible for phloem loading, transport, and unloading specifically. We also discuss the interesting but unaddressed questions relating to, and potential studies on, the adaptation of functional plasmodesmal structures.
Topics: Biological Transport; Phloem; Plant Development; Plants; Plasmodesmata
PubMed: 31872215
DOI: 10.1093/jxb/erz567 -
Current Opinion in Plant Biology Jun 2024Messenger RNAs (mRNAs) are the templates for protein translation but can also act as non-cell-autonomous signaling molecules. Plants input endogenous and exogenous cues... (Review)
Review
Messenger RNAs (mRNAs) are the templates for protein translation but can also act as non-cell-autonomous signaling molecules. Plants input endogenous and exogenous cues to mobile mRNAs and output them to local or systemic target cells and organs to support specific plant responses. Mobile mRNAs form ribonucleoprotein (RNP) complexes with proteins during transport. Components of these RNP complexes could interact with plasmodesmata (PDs), a major mediator of mRNA transport, to ensure mRNA mobility and transport selectivity. Based on advances in the last two to three years, this review summarizes mRNA transport mechanisms in local and systemic signaling from the perspective of RNP complex formation and PD transport. We also discuss the physiological roles of endogenous mRNA transport and the recently revealed roles of non-cell-autonomous mRNAs in inter-organism communication.
Topics: RNA, Messenger; Plasmodesmata; Ribonucleoproteins; RNA, Plant; RNA Transport; Plants; Signal Transduction; Cell Communication
PubMed: 38663258
DOI: 10.1016/j.pbi.2024.102541 -
Frontiers in Plant Science 2022The holoparasitic dodder ( spp.) is able to transfer mRNA and certain plant pathogens (e.g., viruses and bacteria) from the host plant. " Liberibacter asiaticus," the...
The holoparasitic dodder ( spp.) is able to transfer mRNA and certain plant pathogens (e.g., viruses and bacteria) from the host plant. " Liberibacter asiaticus," the phloem-limited causative agent of citrus Huanglongbing, can be transferred from citrus to periwinkle () mediated by dodder. However, characterization of mRNA transport between dodder and citrus/periwinkle remains unclear. In this study, we sequenced transcriptomes of dodder and its parasitizing host, sweet orange ( "Newhall") and periwinkle (), to identify and characterize mRNA transfer between dodder and the host plant during parasitism. The mRNA transfer between dodder and citrus/periwinkle was bidirectional and most of the transfer events occurred in the interface tissue. Compared with the citrus-dodder system, mRNA transfer in the periwinkle-dodder system was more frequent. Function classification revealed that a large number of mRNAs transferred between dodder and citrus/periwinkle were involved in secondary metabolism and stress response. Dodder transcripts encoding proteins associated with microtubule-based processes and cell wall biogenesis were transferred to host tissues. In addition, transcripts involved in translational elongation, plasmodesmata, and the auxin-activated signaling pathway were transmitted between dodder and citrus/periwinkle. In particular, transcripts involved in shoot system development and flower development were transferred between the host and dodder in both directions. The high abundance of dodder-origin transcripts, encoding MIP aquaporin protein, and -adenosylmethionine synthetase 1 protein, in citrus and periwinkle tissues indicated they could play an important biological role in dodder-host interaction. In addition, the uptake of host mRNAs by dodder, especially those involved in seed germination and flower development, could be beneficial for the reproduction of dodder. The results of this study provide new insights into the RNA-based interaction between dodder and host plants.
PubMed: 36072332
DOI: 10.3389/fpls.2022.980033 -
Frontiers in Plant Science 2021Pathogenic microorganisms deliver protein effectors into host cells to suppress host immune responses. Recent findings reveal that phytopathogens manipulate the function...
Pathogenic microorganisms deliver protein effectors into host cells to suppress host immune responses. Recent findings reveal that phytopathogens manipulate the function of plant cell-to-cell communication channels known as plasmodesmata (PD) to promote diseases. Several bacterial and filamentous pathogen effectors have been shown to regulate PD in their host cells. A few effectors of filamentous pathogens have been reported to move from the infected cells to neighboring plant cells through PD; however, it is unclear whether bacterial effectors can traffic through PD in plants. In this study, we determined the intercellular movement of pv. () DC3000 effectors between adjoining plant cells in . We observed that at least 16 DC3000 effectors have the capacity to move from transformed cells to the surrounding plant cells. The movement of the effectors is largely dependent on their molecular weights. The expression of PD regulators, PD-located protein PDLP5 and PDLP7, leads to PD closure and inhibits the PD-dependent movement of a bacterial effector in . Similarly, a 22-amino acid peptide of bacterial flagellin (flg22) treatment induces PD closure and suppresses the movement of a bacterial effector in . Among the mobile effectors, HopAF1 and HopA1 are localized to the plasma membrane (PM) in plant cells. Interestingly, the PM association of HopAF1 does not negatively affect the PD-dependent movement. Together, our findings demonstrate that bacterial effectors are able to move intercellularly through PD in plants.
PubMed: 33959138
DOI: 10.3389/fpls.2021.640277