Exocyst functions in plants: secretion and autophagy

Žárský, Viktor

doi:10.1002/1873-3468.14430

Cited by 22 publications

(17 citation statements)

References 119 publications

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“…Indeed, rRNA has been shown to accumulate in autophagosomes and vacuoles of Arabidopsis when the RNase RNS2 is mutated, and the vacuolar accumulation is blocked by mutation of the AUTOPHAGY5 gene ( Floyd et al , 2015 ). However, whether secretory autophagy also occurs in plants is not yet known ( Zarsky, 2022 ). Additionally, dying cells could potentially be another source of extravesicular exRNAs.…”

Section: Mechanisms Involved In Rna Secretion Into the Apoplastmentioning

confidence: 99%

Extracellular RNA: mechanisms of secretion and potential functions

Borniego

Innes

2023

Journal of Experimental Botany

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Extracellular RNA (exRNA) has long been considered as cellular waste that plants can degrade and utilize to recycle nutrients. However, recent findings highlight the need to reconsider the biological significance of RNAs found outside of plant cells. A handful of studies suggest that the exRNA repertoire, which turns out to be an extremely heterogenous group of non-coding RNAs, comprises species as small as a dozen nucleotides to hundreds of nucleotides long. They are found mostly in free form or associated with RNA-binding proteins, while very few are found inside extracellular vesicles (EVs). Despite their low abundance, small RNAs associated with EVs have been a focus of exRNA research due to their putative role in mediating transkingdom RNA interference. Therefore, non-vesicular exRNAs have remained completely under the radar until very recently. Here we summarize our current knowledge of the RNA species that constitute the extracellular RNAome and discuss mechanisms that could explain the diversity of exRNAs, focusing not only on the potential mechanisms involved in RNA secretion but also on post-release processing of exRNAs. We will also share our thoughts on the putative roles of vesicular and extravesicular exRNAs in plant-pathogen interactions, intercellular communication, and other physiological processes in plants.

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Section: Mechanisms Involved In Rna Secretion Into the Apoplastmentioning

confidence: 99%

Extracellular RNA: mechanisms of secretion and potential functions

Borniego

Innes

2023

Journal of Experimental Botany

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“…The exocyst comprises eight proteins: Exo70, Exo84, Sec3, Sec5, Sec6, Sec8, Sec10 and Sec15 (Lepore et al, 2018; Zeng et al, 2017). This complex is present in nearly all organisms studied to date, including fungi, animals, plants and some protozoa (Boehm & Field, 2019; Lepore et al, 2018; Zarsky, 2022; Zeng et al, 2017). The exocyst tethers vesicles derived from the trans‐Golgi network (TGN) or an endosomal compartment termed the recycling endosome (RE) to the plasma membrane (Figure 1b) (Zeng et al, 2017).…”

Section: The Exocyst Complexmentioning

confidence: 99%

“…The bacteria Xanthomonas campestris or Pseudomonas syringae impair exocyst function to block plant defence responses (Michalopoulou et al, 2022; Reddit et al, 2019; Wang et al, 2019). Due to space constraints, we omit discussion of bacterial interference with the exocyst and refer the reader to recent reviews or commentaries on this subject (Bertoni, 2022; Guichard et al, 2014; Ireton et al, 2018; Zarsky, 2022).…”

Section: Introductionmentioning

confidence: 99%

Exploitation of the host exocyst complex by bacterial pathogens

Ireton

Gyanwali

Herath

et al. 2023

Molecular Microbiology

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Intracellular bacterial pathogens remodel the plasma membrane of eukaryotic cells in order to establish infection. A common and well-studied mechanism of plasma membrane remodelling involves bacterial stimulation of polymerization of the host actin cytoskeleton. Here, we discuss recent results showing that several bacterial pathogens also exploit the host vesicular trafficking pathway of 'polarized exocytosis' to expand and reshape specific regions in the plasma membrane during infection.Polarized exocytosis is mediated by an evolutionarily conserved octameric protein complex termed the exocyst. We describe examples in which the bacteria Listeria monocytogenes, Salmonella enterica serovar Typhimurium, and Shigella flexneri co-opt the exocyst to promote internalization into human cells or intercellular spread within host tissues. We also discuss results showing that Legionella pneumophila or S. flexneri manipulate exocyst components to modify membrane vacuoles to favour intracellular replication or motility of bacteria. Finally, we propose potential ways that pathogens manipulate exocyst function, discuss how polarized exocytosis might promote infection and highlight the importance of future studies to determine how actin polymerization and polarized exocytosis are coordinated to achieve optimal bacterial infection.

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“…Within the secretory pathway, the final stages of vesicle delivery to the PM has been extensively investigated in eukaryotes, and key protein complexes have been identified to contribute to this final stage of secretion, including a tethering complex known as the exocyst complex followed by the SOLUBLE N-ETHYLMALEIMIDE-SENSITIVE FACTOR ADAPTOR PROTEIN RECEPTOR (SNARE) complex (Lipka et al 2007; Saeed et al 2019). Both protein complexes are essential for a large diversity of secretory events throughout the plant lifecycle, and corresponding mutants often display altered development and seedling lethality (Luo et al 2022; Shi et al 2023; Zarsky 2022; Zarsky et al 2020). The octameric exocyst complex is involved in tethering post-Golgi secretory vesicles at the plasma membrane (Saeed et al 2019; Zarsky 2022).…”

Section: Introductionmentioning

confidence: 99%

The ArabidopsisSNAREcomplex genes regulate the early stages of pollen-stigma interactions

Macgregor,

Beronilla,

Goring

2023

Preprint

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In the Brassicaceae, the process of accepting compatible pollen is a key step in successful reproduction and highly regulated following interactions between the pollen and the stigma. Central to this, is the initiation of secretion in the stigma, which is proposed to provide resources to the pollen for hydration and germination and pollen tube growth. Previously, the eight exocyst subunit genes were shown to be required in the Arabidopsis stigma to support these pollen responses. One of the roles of the exocyst is to tether secretory vesicles at the plasma membrane for membrane fusion by the SNARE complex to enable vesicle cargo release. Here, we investigate the role of ArabidopsisSNAREgenes in the stigma for pollen responses. Using a combination of different knockout and knockdownSNAREmutant lines, we show thatVAMP721, VAMP722, SYP121, SYP122andSNAP33are involved in this process. Significant disruptions in pollen hydration were observed following pollination of wildtype pollen on the mutantSNAREstigmas. Overall, these results place the Arabidopsis SNARE complex as a contributor in the stigma for pollen responses and reaffirm the significance of secretion in the stigma to support the pollen-stigma interactions.Key MessageThe VAMP721, VAMP722, SYP121, SYP122 and SNAP33 SNAREs are required in the Arabidopsis stigma for pollen hydration, further supporting a role for vesicle trafficking in the stigma’s pollen responses.

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Exocyst functions in plants: secretion and autophagy

Cited by 22 publications

References 119 publications

Extracellular RNA: mechanisms of secretion and potential functions

Extracellular RNA: mechanisms of secretion and potential functions

Exploitation of the host exocyst complex by bacterial pathogens

The ArabidopsisSNAREcomplex genes regulate the early stages of pollen-stigma interactions

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