| 1. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Extracellular peptide Kratos restricts cell death during vascular development and stress in Arabidopsis
- 2019
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 70:7, s. 2199-2210
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Tidskriftsartikel (refereegranskat)abstract
- During plant vascular development, xylem tracheary elements (TEs) form water-conducting, empty pipes by genetically regulated cell death. Cell death is prevented from spreading to non-TEs by unidentified intercellular mechanisms, downstream of METACASPASE9 (MC9)-mediated regulation of autophagy in TEs. Here, we identified differentially abundant extracellular peptides in vascular-differentiating wild-type and MC9-down-regulated Arabidopsis cell suspensions. A peptide named Kratos rescued the abnormally high ectopic non-TE death resulting from either MC9 knockout or TE-specific overexpression of the ATG5 autophagy protein during experimentally induced vascular differentiation in Arabidopsis cotyledons. Kratos also reduced cell death following mechanical damage and extracellular ROS production in Arabidopsis leaves. Stress-induced but not vascular non-TE cell death was enhanced by another identified peptide, named Bia. Bia is therefore reminiscent of several known plant cell death-inducing peptides acting as damage-associated molecular patterns. In contrast, Kratos plays a novel extracellular cell survival role in the context of development and during stress response.
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| 2. |
- Kimura, Sachie, et al.
(författare)
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CRK2 and C-terminal phosphorylation of NADPH oxidase RBOHD regulate reactive oxygen species production in arabidopsis
- 2020
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Ingår i: Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 32:4, s. 1063-1080
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Tidskriftsartikel (refereegranskat)abstract
- Reactive oxygen species (ROS) are important messengers in eukaryotic organisms, and their production is tightly controlled. Active extracellular ROS production by NADPH oxidases in plants is triggered by receptor-like protein kinase-dependent signaling networks. Here, we show that CYSTEINE-RICH RLK2 (CRK2) kinase activity is required for plant growth and CRK2 exists in a preformed complex with the NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) in Arabidopsis (Arabidopsis thaliana). Functional CRK2 is required for the full elicitor-induced ROS burst, and consequently the crk2 mutant is impaired in defense against the bacterial pathogen Pseudomonas syringae pv tomato DC3000. Our work demonstrates that CRK2 regulates plant innate immunity. We identified in vitro CRK2-dependent phosphorylation sites in the C-terminal region of RBOHD. Phosphorylation of S703 RBOHD is enhanced upon flg22 treatment, and substitution of S703 with Ala reduced ROS production in Arabidopsis. Phylogenetic analysis suggests that phospho-sites in the C-terminal region of RBOHD are conserved throughout the plant lineage and between animals and plants. We propose that regulation of NADPH oxidase activity by phosphorylation of the C-terminal region might be an ancient mechanism and that CRK2 is an important element in regulating microbe-associated molecular pattern-triggered ROS production.
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| 3. |
- Salojarvi, Jarkko, et al.
(författare)
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Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch
- 2017
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Ingår i: Nature Genetics. - : NATURE PUBLISHING GROUP. - 1061-4036 .- 1546-1718. ; 49:6, s. 904-912
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Tidskriftsartikel (refereegranskat)abstract
- Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.
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| 4. |
- Vaattovaara, Aleksia, et al.
(författare)
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High-throughput sequencing data and the impact of plant gene annotation quality
- 2019
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 70:4, s. 1069-1076
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Tidskriftsartikel (refereegranskat)abstract
- The use of draft genomes of different species and re-sequencing of accessions and populations are now common tools for plant biology research. The de novo assembled draft genomes make it possible to identify pivotal divergence points in the plant lineage and provide an opportunity to investigate the genomic basis and timing of biological innovations by inferring orthologs between species. Furthermore, re-sequencing facilitates the mapping and subsequent molecular characterization of causative loci for traits, such as those for plant stress tolerance and development. In both cases high-quality gene annotation-the identification of protein-coding regions, gene promoters, and 5'- and 3'-untranslated regions-is critical for investigation of gene function. Annotations are constantly improving but automated gene annotations still require manual curation and experimental validation. This is particularly important for genes with large introns, genes located in regions rich with transposable elements or repeats, large gene families, and segmentally duplicated genes. In this opinion paper, we highlight the impact of annotation quality on evolutionary analyses, genome-wide association studies, and the identification of orthologous genes in plants. Furthermore, we predict that incorporating accurate information from manual curation into databases will dramatically improve the performance of automated gene predictors.
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| 5. |
- Wrzaczek, Michael, et al.
(författare)
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GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis
- 2015
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Ingår i: EMBO Journal. - : EMBO. - 0261-4189 .- 1460-2075. ; 31:1, s. 55-66
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Tidskriftsartikel (refereegranskat)abstract
- Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor.
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| 6. |
- Wrzaczek, Michael, et al.
(författare)
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Transcriptional regulation of the CRK/DUF26 group of Receptor-like rotein kinases by ozone and plant hormones in Arabidopsis
- 2010
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Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 10, s. 95-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Plant Receptor-like/Pelle kinases (RLK) are a group of onserved signalling components that regulate developmental programs and esponses to biotic and abiotic stresses. One of the largest RLK groups s formed by the Domain of Unknown Function 26 (DUF26) RLKs, also called ysteine-rich Receptor-like Kinases (CRKs), which have been suggested to lay important roles in the regulation of pathogen defence and rogrammed cell death. Despite the vast number of RLKs present in lants, however, only a few of them have been functionally haracterized. esults: We examined the transcriptional regulation of all Arabidopsis RKs by ozone (O(3)), high light and pathogen/ elicitor reatment-conditions known to induce the production of reactive oxygen pecies (ROS) in various subcellular compartments. Several CRKs were ranscriptionally induced by exposure to O(3) but not by light stress. (3) induces an extracellular oxidative burst, whilst light stress leads o ROS production in chloroplasts. Analysis of publicly available icroarray data revealed that the transcriptional responses of the CRKs o O(3) were very similar to responses to microbes or athogen-associated molecular patterns (PAMPs). Several mutants altered n hormone biosynthesis or signalling showed changes in basal and (3)-induced transcriptional responses. onclusions: Combining expression analysis from multiple treatments with utants altered in hormone biosynthesis or signalling suggest a model in hich O(3) and salicylic acid (SA) activate separate signaling pathways hat exhibit negative crosstalk. Although O(3) is classified as an biotic stress to plants, transcriptional profiling of CRKs showed trong similarities between the O(3) and biotic stress responses.
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