| 1. |
- Amstutz, Cynthia L., et al.
(författare)
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An atypical short-chain dehydrogenase–reductase functions in the relaxation of photoprotective qH in Arabidopsis
- 2020
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Ingår i: Nature Plants. - : Nature Publishing Group. - 2055-026X .- 2055-0278. ; 6, s. 154-166
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Tidskriftsartikel (refereegranskat)abstract
- Photosynthetic organisms experience wide fluctuations in light intensity and regulate light harvesting accordingly to prevent damage from excess energy. The antenna quenching component qH is a sustained form of energy dissipation that protects the photosynthetic apparatus under stress conditions. This photoprotective mechanism requires the plastid lipocalin LCNP and is prevented by SUPPRESSOR OF QUENCHING1 (SOQ1) under non-stress conditions. However, the molecular mechanism of qH relaxation has yet to be resolved. Here, we isolated and characterized RELAXATION OF QH1 (ROQH1), an atypical short-chain dehydrogenase–reductase that functions as a qH-relaxation factor in Arabidopsis. The ROQH1 gene belongs to the GreenCut2 inventory specific to photosynthetic organisms, and the ROQH1 protein localizes to the chloroplast stroma lamellae membrane. After a cold and high-light treatment, qH does not relax in roqh1 mutants and qH does not occur in leaves overexpressing ROQH1. When the soq1 and roqh1 mutations are combined, qH can neither be prevented nor relaxed and soq1 roqh1 displays constitutive qH and light-limited growth. We propose that LCNP and ROQH1 perform dosage-dependent, antagonistic functions to protect the photosynthetic apparatus and maintain light-harvesting efficiency in plants.
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| 2. |
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| 3. |
- Bhalerao, Rishikesh P.
(författare)
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Root hydrotropism is controlled via a cortex-specific growth mechanism
- 2017
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Plants can acclimate by using tropisms to link the direction of growth to environmental conditions. Hydrotropism allows roots to forage for water, a process known to depend on abscisic acid (ABA) but whose molecular and cellular basis remains unclear. Here we show that hydrotropism still occurs in roots after laser ablation removed the meristem and root cap. Additionally, targeted expression studies reveal that hydrotropism depends on the ABA signalling kinase SnRK2.2 and the hydrotropism-specific MIZ1, both acting specifically in elongation zone cortical cells. Conversely, hydrotropism, but not gravitropism, is inhibited by preventing differential cell-length increases in the cortex, but not in other cell types. We conclude that root tropic responses to gravity and water are driven by distinct tissue-based mechanisms. In addition, unlike its role in root gravitropism, the elongation zone performs a dual function during a hydrotropic response, both sensing a water potential gradient and subsequently undergoing differential growth.
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| 4. |
- Bourdon, Matthieu, et al.
(författare)
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Ectopic callose deposition into woody biomass modulates the nano-architecture of macrofibrils
- 2023
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Ingår i: Nature Plants. - : Springer Nature. - 2055-0278 .- 2055-026X. ; 9:9, s. 1530-1546
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Tidskriftsartikel (refereegranskat)abstract
- Plant biomass plays an increasingly important role in the circular bioeconomy, replacing non-renewable fossil resources. Genetic engineering of this lignocellulosic biomass could benefit biorefinery transformation chains by lowering economic and technological barriers to industrial processing. However, previous efforts have mostly targeted the major constituents of woody biomass: cellulose, hemicellulose and lignin. Here we report the engineering of wood structure through the introduction of callose, a polysaccharide novel to most secondary cell walls. Our multiscale analysis of genetically engineered poplar trees shows that callose deposition modulates cell wall porosity, water and lignin contents and increases the lignin–cellulose distance, ultimately resulting in substantially decreased biomass recalcitrance. We provide a model of the wood cell wall nano-architecture engineered to accommodate the hydrated callose inclusions. Ectopic polymer introduction into biomass manifests in new physico-chemical properties and offers new avenues when considering lignocellulose engineering.
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| 5. |
- Camara-Leret, R., et al.
(författare)
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Fundamental species traits explain provisioning services of tropical American palms
- 2017
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- The well-being of the global human population rests on provisioning services delivered by 12% of the Earth's similar to 400,000 plant species(1). Plant utilization by humans is influenced by species traits(2-4), but it is not well understood which traits underpin different human needs(5). Here, we focus on palms (Arecaceae), one of the most economically important plant groups globally(6), and demonstrate that provisioning services related to basic needs, such as food and medicine, show a strong link to fundamental functional and geographic traits. We integrate data from 2,201 interviews on plant utilization from three biomes in South America-spanning 68 communities, 43 ethnic groups and 2,221 plant uses-with a dataset of 4 traits (leaf length, stem volume, fruit volume, geographic range size) and a species-level phylogeny(7). For all 208 palm species occurring in our study area, we test for relations between their traits and perceived value. We find that people preferentially use large, widespread species rather than small, narrow-ranged species, and that different traits are linked to different uses. Further, plant size and geographic range size are stronger predictors of ecosystem service realization for palm services related to basic human needs than less-basic needs (for example, ritual). These findings suggest that reliance on plant size and availability may have prevented our optimal realization of wild-plant services, since ecologically rare yet functionally important (for example, chemically) clades may have been overlooked. Beyond expanding our understanding of how local people use biodiversity in mega-diverse regions, our traitand phylogeny-based approach helps to understand the processes that underpin ecosystem service realization, a necessary step to meet societal needs in a changing world with a growing human population(5,8).
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| 6. |
- Capovilla, Giovanna, et al.
(författare)
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PORCUPINE regulates development in response to temperature through alternative splicing
- 2018
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Ingår i: Nature plants. - : Nature Publishing Group. - 2055-026X .- 2055-0278. ; 4:8, s. 534-539
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings suggest that alternative splicing has a critical role in controlling the responses of plants to temperature variations. However, alternative splicing factors in plants are largely uncharacterized. Here we establish the putative splice regulator, PORCUPINE (PCP), as temperature-specific regulator of development in Arabidopsis thaliana. Our findings point to the misregulation of WUSCHEL and CLAVATA3 as the possible cause for the meristem defects affecting the pcp-1 loss-of-function mutants at low temperatures.
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| 7. |
- Chen, Ming, et al.
(författare)
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Distinct structural modulation of photosystem I and lipid environment stabilizes its tetrameric assembly
- 2020
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 6:3, s. 314-
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Tidskriftsartikel (refereegranskat)abstract
- Photosystem I (PSI) is able to form different oligomeric states across various species. To reveal the structural basis for PSI dimerization and tetramerization, we structurally investigated PSI from the cyanobacterium Anabaena. This revealed a disrupted trimerization domain due to lack of the terminal residues of PsaL in the lumen, which resulted in PSI dimers with loose connections between monomers and weaker energy-coupled chlorophylls than in the trimer. At the dimer surface, specific phospholipids, cofactors and interactions in combination facilitated recruitment of another dimer to form a tetramer. Taken together, the relaxed luminal connections and lipid specificity at the dimer interface account for membrane curvature. PSI tetramer assembly appears to increase the surface area of the thylakoid membrane, which would contribute to PSI crowding. Photosystem I from the cyanobacterium Anabaena has a disrupted trimerization domain resulting in dimers with loose connections between monomers. Phospholipids and cofactors at the dimer surface facilitate further dimerization to form a tetramer.
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| 8. |
- Conn, Vanessa M., et al.
(författare)
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A circRNA from SEPALLATA3 regulates splicing of its cognate mRNA through R-loop formation
- 2017
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Ingår i: Nature Plants. - : Nature Publishing Group. - 2055-026X .- 2055-0278. ; 3:5
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Tidskriftsartikel (refereegranskat)abstract
- Circular RNAs (circRNAs) are a diverse and abundant class of hyper-stable, non-canonical RNAs that arise through a form of alternative splicing (AS) called back-splicing. These single-stranded, covalently-closed circRNA molecules have been identified in all eukaryotic kingdoms of life(1), yet their functions have remained elusive. Here, we report that circRNAs can be used as bona fide biomarkers of functional, exon-skipped AS variants in Arabidopsis, including in the homeotic MADS-box transcription factor family. Furthermore, we demonstrate that circRNAs derived from exon 6 of the SEPALLATA3 (SEP3) gene increase abundance of the cognate exon-skipped AS variant (SEP3.3 which lacks exon 6), in turn driving floral homeotic phenotypes. Toward demonstrating the underlying mechanism, we show that the SEP3 exon 6 circRNA can bind strongly to its cognate DNA locus, forming an RNA: DNA hybrid, or R-loop, whereas the linear RNA equivalent bound significantly more weakly to DNA. R-loop formation results in transcriptional pausing, which has been shown to coincide with splicing factor recruitment and AS(2-4). This report presents a novel mechanistic insight for how at least a subset of circRNAs probably contribute to increased splicing efficiency of their cognate exon-skipped messenger RNA and provides the first evidence of an organismal-level phenotype mediated by circRNA manipulation.
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| 9. |
- Derkacheva, Maria, et al.
(författare)
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H2A deubiquitinases UBP12/13 are part of the Arabidopsis polycomb group protein system
- 2016
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Ingår i: Nature plants. - 2055-026X .- 2055-0278. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- Polycomb group (PcG) proteins form an epigenetic memory system in plants and animals, but interacting proteins are poorly known in plants. Here, we have identified Arabidopsis UBIQUITIN SPECIFIC PROTEASES (USP; UBP in plant and yeasts) 12 and 13 as partners of the plant-specific PcG protein LIKE HETEROCHROMATIN PROTEIN 1 (LHP1). UBP12 binds to chromatin of PcG target genes and is required for histone H3 lysine 27 trimethylation and repression of a subset of PcG target genes. Plants lacking UBP12 and UBP13 developed autonomous endosperm in the absence of fertilization. We have identified UBP12 and UBP13 as new proteins in the plant PcG regulatory network. UBP12 and UBP13 belong to an ancient gene family and represent plant homologues of metazoan USP7. We have found that Drosophila USP7 shares a function in heterochromatic gene repression with UBP12/13 and their homologue UBP26. In summary, we demonstrate that USP7-like proteins are essential for gene silencing in diverse genomic contexts.
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| 10. |
- Derkacheva, Maria, et al.
(författare)
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H2A deubiquitinases UBP12/13 are part of the Arabidopsis polycomb group protein system
- 2016
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Ingår i: Nature Plants. - : Springer Science and Business Media LLC. - 2055-026X .- 2055-0278. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Polycomb group (PcG) proteins form an epigenetic memory system in plants and animals, but interacting proteins are poorly known in plants. Here, we have identified Arabidopsis UBIQUITIN SPECIFIC PROTEASES (USP; UBP in plant and yeasts) 12 and 13 as partners of the plant-specific PcG protein LIKE HETEROCHROMATIN PROTEIN 1 (LHP1). UBP12 binds to chromatin of PcG target genes and is required for histone H3 lysine 27 trimethylation and repression of a subset of PcG target genes. Plants lacking UBP12 and UBP13 developed autonomous endosperm in the absence of fertilization. We have identified UBP12 and UBP13 as new proteins in the plant PcG regulatory network. UBP12 and UBP13 belong to an ancient gene family and represent plant homologues of metazoan USP7. We have found that Drosophila USP7 shares a function in heterochromatic gene repression with UBP12/13 and their homologue UBP26. In summary, we demonstrate that USP7-like proteins are essential for gene silencing in diverse genomic contexts.
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