Project description:Plants display remarkable developmental and phenotypic plasticity in order to adapt to their environment. It has long been postulated that epigenetics plays a key role in these processes, but with one or two exceptions, solid evidence for the role of epigenetic variation in these processes is lacking. A key impediment to understanding these processes is the lack of information on the extent of epigenetic variation and how it relates to genetic and phenotypic variation in natural population, both over the lifecycle of an individual, and over evolutionary time. Here we show that genetic variants under selection in the north of Sweden appear to drive variation in DNA methylation, which in turn is highly correlated with local climate. Selective sweeps and genetic variants associated with adaptation to the local environment have previously been identified within the Swedish Arabidopsis population. Our finding that they harbour variants responsible for climate associated epigenetic variation strongly supports the role of epigenetic processes in local adaptation. These findings provide a basis for further dissecting the role of epigenetics in local adaptation at the molecular level Bisulfite sequencing of 113 F2 crosses between T550 and Brosarp-11-135.
Project description:Many Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities where signals may be perceived across species. We here present a newly found natural quorum sensing inhibitor, produced by the pseudomonads Pseudomonas sp. B13 and Pseudomonas reinekei MT1 as a blind end in the biodegradation of organochloride xenobiotics, which inhibits quorum sensing in P. aeruginosa in naturally occurring concentrations. This catabolite, 4-methylenebut-2-en-4-olide, also known as protoanemonin, has been reported to possess antibacterial properties, but seems to have dual functions. Using transcriptomics and proteomics, we found that protoanemonin significantly reduced expression of genes and secretion of proteins known to be under control of quorum sensing in P. aeruginosa. Moreover, we found activation of genes and gene products involved in iron starvation response. It is thus likely that inhibition of quorum sensing, as the production of antibiotics, is a phenomenon found in complex bacterial communities.
Project description:Many Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities where signals may be perceived across species. We here present a newly found natural quorum sensing inhibitor, produced by the pseudomonads Pseudomonas sp. B13 and Pseudomonas reinekei MT1 as a blind end in the biodegradation of organochloride xenobiotics, which inhibits quorum sensing in P.M-bM-^@M-^Caeruginosa in naturally occurring concentrations. This catabolite, 4-methylenebut-2-en-4-olide, also known as protoanemonin, has been reported to possess antibacterial properties, but seems to have dual functions. Using transcriptomics and proteomics, we found that protoanemonin significantly reduced expression of genes and secretion of proteins known to be under control of quorum sensing in P.M-bM-^@M-^Caeruginosa. Moreover, we found activation of genes and gene products involved in iron starvation response. It is thus likely that inhibition of quorum sensing, as the production of antibiotics, is a phenomenon found in complex bacterial communities. Strain P. aeruginosa MPAO1 was cultivated under defined ABT medium. The orginal culture was divided in the early exponential phase into two parts. One was treated with 125M-NM-<M Protoanemonin and the other served as a control. The experiment was performed in duplicates.
Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.
Project description:Plants display remarkable developmental and phenotypic plasticity in order to adapt to their environment. It has long been postulated that epigenetics plays a key role in these processes, but with one or two exceptions, solid evidence for the role of epigenetic variation in these processes is lacking. A key impediment to understanding these processes is the lack of information on the extent of epigenetic variation and how it relates to genetic and phenotypic variation in natural population, both over the lifecycle of an individual, and over evolutionary time. Here we show that genetic variants under selection in the north of Sweden appear to drive variation in DNA methylation, which in turn is highly correlated with local climate. Selective sweeps and genetic variants associated with adaptation to the local environment have previously been identified within the Swedish Arabidopsis population. Our finding that they harbour variants responsible for climate associated epigenetic variation strongly supports the role of epigenetic processes in local adaptation. These findings provide a basis for further dissecting the role of epigenetics in local adaptation at the molecular level
Project description:DNA methylation is a key epigenetic mark that impacts gene expression and represses transposable elements (TEs) in eukaryotes. Numerous examples of cis-elements targeted by DNA methylation, particularly at CG sites (mCG), have been reported to be under selective pressure in animals and plants. By contrast, there is limited knowledge of trans-regulators of mCG leading to adaptation. Here, using genome-wide association studies, we identify CELL DIVISION CYCLE-ASSOCIATED PROTEIN 7 ALPHA (CDCA7α) as a trans-regulator of mCG in natural populations of Arabidopsis thaliana. CDCA7α and its paralog, CDCA7β, directly bind to the chromatin remodeler DECREASE IN DNA METHYLATION 1 (DDM1), which facilitates access of methyltransferases to DNA. CDCA7α/β selectively regulates mCG and minimally impacts other DDM1-dependent processes such as non-CG methylation and histone variant deposition. We identify the cis-regulatory sequence modulating CDCA7α expression in natural populations and determining the degree of mCG and TE silencing. The geographic distribution of CDCA7α alleles suggests that new alleles have repeatedly expanded to novel ecological niches, indicating a potential role in local adaptation. Altogether, our findings provide new insight into how changes in global DNA methylation levels through transcriptional regulation of the epigenetic machinery have the capacity to facilitate local adaptation.