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- Bozhkov, Peter, et al.
(författare)
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Autophagy-related approaches for improving nutrient use efficiency and crop yield protection
- 2018
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 69, s. 1335-1353
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Forskningsöversikt (refereegranskat)abstract
- Autophagy is a eukaryotic catabolic pathway essential for growth and development. In plants, it is activated in response to environmental cues or developmental stimuli. However, in contrast to other eukaryotic systems, we know relatively little regarding the molecular players involved in autophagy and the regulation of this complex pathway. In the framework of the COST (European Cooperation in Science and Technology) action TRANSAUTOPHAGY (2016-2020), we decided to review our current knowledge of autophagy responses in higher plants, with emphasis on knowledge gaps. We also assess here the potential of translating the acquired knowledge to improve crop plant growth and development in a context of growing social and environmental challenges for agriculture in the near future.
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| 4. |
- Bozhkov, Peter, et al.
(författare)
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Transcriptional stimulation of autophagy improves plant fitness
- 2017
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- The present invention provides to a method for enhancing the productivity of a plant by genetically modifying the genome of the plant to over-express at least one autophagy-related (ATG) protein selected from the group consisting of ATG5 and ATG7. The invention further provides a genetically modified plant characterized by over-expression of least one autophagy related (ATG) protein selected from the group consisting of ATG5 and ATG7.Additionally the use of a transgene encoding atleast one autophagy related (ATG) protein selected from the group consisting of ATG5 and ATG7for enhancing the productivity of a plantis disclosed.
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| 5. |
- de Jonge, Jennifer, et al.
(författare)
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Salicylic acid interferes with GFP fluorescence in vivo
- 2017
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 68, s. 1689-1696
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescent proteins have become essential tools for cell biologists. They are routinely used by plant biologists for protein and promoter fusions to infer protein localization, tissue-specific expression and protein abundance. When studying the effects of biotic stress on chromatin, we unexpectedly observed a decrease in GFP signal intensity upon salicylic acid (SA) treatment in Arabidopsis lines expressing histone H1-GFP fusions. This GFP signal decrease was dependent on SA concentration. The effect was not specific to the linker histone H1-GFP fusion but was also observed for the nucleosomal histone H2A-GFP fusion. This result prompted us to investigate a collection of fusion proteins, which included different promoters, subcellular localizations and fluorophores. In all cases, fluorescence signals declined strongly or disappeared after SA application. No changes were detected in GFP-fusion protein abundance when fluorescence signals were lost indicating that SA does not interfere with protein stability but GFP fluorescence. In vitro experiments showed that SA caused GFP fluorescence reduction only in vivo but not in vitro, suggesting that SA requires cellular components to cause fluorescence reduction. Together, we conclude that SA can interfere with the fluorescence of various GFP-derived reporter constructs in vivo. Assays that measure relocation or turnover of GFP-tagged proteins upon SA treatment should therefore be evaluated with caution.
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| 6. |
- Dvorák Tomastíková, Eva, et al.
(författare)
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Polycomb Repressive Complex 2 and KRYPTONITE regulate pathogen-induced programmed cell death in Arabidopsis
- 2021
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 185, s. 2003-2021
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Tidskriftsartikel (refereegranskat)abstract
- The Polycomb Repressive Complex 2 (PRC2) is well-known for its role in controlling developmental transitions by suppressing the premature expression of key developmental regulators. Previous work revealed that PRC2 also controls the onset of senescence, a form of developmental programmed cell death (PCD) in plants. Whether the induction of PCD in response to stress is similarly suppressed by the PRC2 remained largely unknown. In this study, we explored whether PCD triggered in response to immunity- and disease-promoting pathogen effectors is associated with changes in the distribution of the PRC2-mediated histone H3 lysine 27 trimethylation (H3K27me3) modification in Arabidopsis thaliana. We furthermore tested the distribution of the heterochromatic histone mark H3K9me2, which is established, to a large extent, by the H3K9 methyltransferase KRYPTONITE, and occupies chromatin regions generally not targeted by PRC2. We report that effector-induced PCD caused major changes in the distribution of both repressive epigenetic modifications and that both modifications have a regulatory role and impact on the onset of PCD during pathogen infection. Our work highlights that the transition to pathogen-induced PCD is epigenetically controlled, revealing striking similarities to developmental PCD.
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| 7. |
- Hafrén, Anders, et al.
(författare)
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NBR1-mediated antiviral xenophagy in plant immunity
- 2017
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8627 .- 1554-8635. ; 13, s. 2000-2001
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Annan publikation (refereegranskat)abstract
- Macroautophagy/autophagy intersects with metazoan virus infections in highly complex and multifaceted ways. Autophagy mechanisms are part of antiviral immunity, but can be manipulated by several viruses to the benefit of infection. In plants, however, the roles of autophagy in virus infections have only recently started to emerge. Here, we present and discuss our recent study that identified 2 prominent functions of autophagy upon cauliflower mosaic virus (CaMV) infection in Arabidopsis. We found that "bulk" autophagy significantly extended the life span of infected plants and increased total virus production. In addition to this proviral role, we discovered that the selective autophagy receptor protein AT4G24690/NBR1 binds viral particles to mediate their xenophagic degradation. Intriguingly, CaMV inclusion bodies protect viral particles from xenophagy and thus represent a sophisticated strategy to counter the antiviral capacity while maintaining the proviral activity of autophagy. Together, our study gives a seminal description of how autophagy is integrated into host immunity and viral pathogenesis in plants, and provides a primary example for removal of a plant pathogen by xenophagy.
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| 8. |
- Hafrén, Anders, et al.
(författare)
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Selective autophagy limits cauliflower mosaic virus infection by NBR1-mediated targeting of viral capsid protein and particles
- 2017
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 114, s. E2026-E2035
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Tidskriftsartikel (refereegranskat)abstract
- Autophagy plays a paramount role in mammalian antiviral immunity including direct targeting of viruses and their individual components, andmany viruses have evolved measures to antagonize or even exploit autophagy mechanisms for the benefit of infection. In plants, however, the functions of autophagy in host immunity and viral pathogenesis are poorly understood. In this study, we have identified both anti-and proviral roles of autophagy in the compatible interaction of cauliflower mosaic virus (CaMV), a double-stranded DNA pararetrovirus, with the model plant Arabidopsis thaliana. We show that the autophagy cargo receptor NEIGHBOR OF BRCA1 (NBR1) targets nonassembled and virus particle-forming capsid proteins to mediate their autophagy-dependent degradation, thereby restricting the establishment of CaMV infection. Intriguingly, the CaMV-induced virus factory inclusions seem to protect against autophagic destruction by sequestering capsid proteins and coordinating particle assembly and storage. In addition, we found that virus-triggered autophagy prevents extensive senescence and tissue death of infected plants in a largely NBR1-independent manner. This survival function significantly extends the timespan of virus production, thereby increasing the chances for virus particle acquisition by aphid vectors and CaMV transmission. Together, our results provide evidence for the integration of selective autophagy into plant immunity against viruses and reveal potential viral strategies to evade and adapt autophagic processes for successful pathogenesis.
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| 9. |
- Hafrén, Anders, et al.
(författare)
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Turnip Mosaic Virus Counteracts Selective Autophagy of the Viral Silencing Suppressor HCpro
- 2018
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 176, s. 649-662
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Tidskriftsartikel (refereegranskat)abstract
- Autophagy is a conserved intracellular degradation pathway and has emerged as a key mechanism of antiviral immunity in metazoans, including the selective elimination of viral components. In turn, some animal viruses are able to escape and modulate autophagy for enhanced pathogenicity. Whether host autophagic responses and viral countermeasures play similar roles in plant-virus interactions is not well understood. Here, we have identified selective autophagy as antiviral pathway during plant infection with turnip mosaic virus (TuMV), a positive-stranded RNA potyvirus. We show that the autophagy cargo receptor NBR1 suppresses viral accumulation by targeting the viral RNA silencing suppressor helper-component proteinase (HCpro), presumably in association with virus-induced RNA granules. Intriguingly, TuMV seems to antagonize NBR1-dependent autophagy during infection by the activity of distinct viral proteins, thereby limiting its antiviral capacity. We also found that NBR1-independent bulk autophagy prevents premature plant death, thus extending the lifespan of virus reservoirs and particle production. Together, our study highlights a conserved role of selective autophagy in antiviral immunity and suggests the evolvement of viral protein functions to inhibit autophagy processes, despite a potential trade-off in host survival.
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| 10. |
- Hofius, Daniel
(författare)
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Arabidopsis RING-type E3 ubiquitin ligase XBAT35.2 promotes proteasome-dependent degradation of ACD11 to attenuate abiotic stress tolerance
- 2020
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Ingår i: Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 104, s. 1712-1723
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Tidskriftsartikel (refereegranskat)abstract
- Plants employ multiple mechanisms to cope with a constantly changing and challenging environment, including using the ubiquitin proteasome system (UPS) to alter their proteome to assist in initiating, modulating and terminating responses to stress. We previously reported that the ubiquitin ligase XBAT35.2 mediates the proteasome-dependent degradation of Accelerated Cell Death 11 (ACD11) to promote pathogen defense. Here, we demonstrate roles for XBAT35.2 and ACD11 in abiotic stress tolerance. As seen in response to pathogen infection, abiotic stress stabilizes XBAT35.2 and the abundance of ACD11 rose consistently with increasing concentrations of abscisic acid (ABA) and salt. Surprisingly, exposure to ABA and salt increased the stability of ACD11, and the overexpression of ACD11 improves plant survival of salt and drought stress, suggesting a role for ACD11 in promoting tolerance. Prolonged exposure to high concentrations of ABA or salt resulted in ubiquitination and the proteasome-dependent degradation of ACD11, however. The stress-induced turnover of ACD11 requires XBAT35.2, as degradation is slowed in the absence of the E3 ubiquitin ligase. Consistent with XBAT35.2 mediating the proteasome-dependent degradation of ACD11, the loss of E3 ubiquitin ligase function enhances the tolerance of salt and drought stress, whereas overexpression increases sensitivity. A model is presented where, upon the perception of abiotic stress, ACD11 abundance increases to promote tolerance. Meanwhile, XBAT35.2 accumulates and in turn promotes the degradation of ACD11 to attenuate the stress response. The results characterize XBAT35.2 as an E3 ubiquitin ligase with opposing roles in abiotic and biotic stress.
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