| 1. |
- 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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| 2. |
- 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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| 3. |
- Liu, Qinsong, et al.
(författare)
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Vacuole Integrity Maintained by DUF300 Proteins Is Required for Brassinosteroid Signaling Regulation
- 2018
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Ingår i: Molecular Plant. - : Cell Press. - 1674-2052 .- 1752-9867. ; 11:4, s. 553-567
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Tidskriftsartikel (refereegranskat)abstract
- Brassinosteroid (BR) hormone signaling controls multiple processes during plant growth and development and is initiated at the plasma membrane through the receptor kinase BRASSINOSTEROID INSENSITIVE1 (BRI1) together with co-receptors such as BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1). BRI1 abundance is regulated by endosomal recycling and vacuolar targeting, but the role of vacuole-related proteins in BR receptor dynamics and BR responses remains elusive. Here, we show that the absence of two DUF300 domain-containing tonoplast proteins, LAZARUS1 (LAZ1) and LAZ1 HOMOLOG1 (LAZ1H1), causes vacuole morphology defects, growth inhibition, and constitutive activation of BR signaling. Intriguingly, tonoplast accumulation of BAK1 was substantially increased and appeared causally linked to enhanced BRI1 trafficking and degradation in laz1 laz1h1 plants. Since unrelated vacuole mutants exhibited normal BR responses, our findings indicate that DUF300 proteins play distinct roles in the regulation of BR signaling by maintaining vacuole integrity required to balance subcellular BAK1 pools and BR receptor distribution.
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| 4. |
- Minina, Alyona, et al.
(författare)
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Transcriptional stimulation of rate-limiting components of the autophagic pathway improves plant fitness
- 2018
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 69, s. 1415-1432
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Tidskriftsartikel (refereegranskat)abstract
- Autophagy is a major catabolic process whereby autophagosomes deliver cytoplasmic content to the lytic compartment for recycling. Autophagosome formation requires two ubiquitin-like systems conjugating Atg12 with Atg5, and Atg8 with lipid phosphatidylethanolamine (PE), respectively. Genetic suppression of these systems causes autophagy-deficient phenotypes with reduced fitness and longevity. We show that Atg5 and the E1-like enzyme, Atg7, are rate-limiting components of Atg8-PE conjugation in Arabidopsis. Overexpression of ATG5 or ATG7 stimulates Atg8 lipidation, autophagosome formation, and autophagic flux. It also induces transcriptional changes opposite to those observed in atg5 and atg7 mutants, favoring stress resistance and growth. As a result, ATG5-or ATG7-over-expressing plants exhibit increased resistance to necrotrophic pathogens and oxidative stress, delayed aging and enhanced growth, seed set, and seed oil content. This work provides an experimental paradigm and mechanistic insight into genetic stimulation of autophagy in planta and shows its efficiency for improving plant productivity.
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| 5. |
- Üstün, Suayib, et al.
(författare)
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Anti- and pro-microbial roles of autophagy in plant-bacteria interactions
- 2018
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8627 .- 1554-8635. ; 14, s. 1465-1466
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Annan publikation (refereegranskat)abstract
- Macroautophagy/autophagy and the ubiquitin-proteasome system (UPS) are major proteolytic pathways that are increasingly recognized as battlegrounds during host-microbe interactions in eukaryotes. In plants, the UPS has emerged as central component of innate immunity and is manipulated by bacterial pathogens to enhance virulence. Autophagy has been ascribed a similar importance for anti-bacterial immunity in animals, but the contribution of autophagy to host-bacteria interactions remained elusive in plants. Here, we present and discuss our recent findings that revealed anti- and pro-bacterial roles of autophagy pathways during bacterial infection in the model plant Arabidopsis thaliana. We discovered that selective autophagy mediated by the autophagy cargo receptor AT4G24690/NBR1 limits growth of Pseudomonas syringae pv. tomato DC3000 (Pst) by suppressing the establishment of an aqueous extracellular space (water-soaking'). In turn, Pseudomonas employs the effector protein HopM1 to activate autophagy and proteasome degradation (proteaphagy'), thereby enhancing its pathogenicity. Thus, our study demonstrates that distinct selective autophagy pathways contribute to host immunity and bacterial pathogenesis during Pst infection and provide evidence for an intimate crosstalk between the proteasome and autophagy system in plant-bacterial interactions.
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| 6. |
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