Summary Environmental stresses can result in a wide range of physiological and molecular responses in plants. These responses can also impact epigenetic information in genomes, especially at the level of DNA methylation (5-methylcytosine). DNA methylation is the hallmark heritable epigenetic modification and plays a key role in silencing transposable elements (TEs). Although DNA methylation is an essential epigenetic mechanism, fundamental aspects of its contribution to stress responses and adaptation remain obscure. We investigated epigenome dynamics of wild strawberry (Fragaria vesca) in response to variable ecologically relevant environmental conditions at the DNA methylation level. F. vesca methylome responded with great plasticity to ecologically relevant abiotic and hormonal stresses. Thermal stress resulted in substantial genome-wide loss of DNA methylation. Notably, all tested stress conditions resulted in marked hot spots of differential DNA methylation near centromeric or pericentromeric regions, particularly in the non-symmetrical DNA methylation context. Additionally, we identified differentially methylated regions (DMRs) within promoter regions of transcription factor (TF) superfamilies involved in plant stress-response and assessed the effects of these changes on gene expression. These findings improve our understanding on stress-response at the epigenome level by highlighting the correlation between DNA methylation, TEs and gene expression regulation in plants subjected to a broad range of environmental stresses.

A hyperresponsive tool to assess supramolecular catalysis, the cyclization of di-epoxides into cyclic ethers is used to elucidate the difference between pnictogen-bonding and Lewis acid catalysis systematically. For all stereoisomers, most tested catalysts follow the Baldwin rules. Brønsted acid and anion-π catalysis afford almost only Baldwin products. Lewis acids such as SbCl 3 , BF 3 and BiCl 3 give the poorest selectivity, with at least 50 % Baldwin (B) products for all stereoisomers. In clear contrast, optimized pnictogen-bonding catalysts operating on the Sb(III) and the Sb(V) level give the fused anti-Baldwin (A) bicycles as the main product of trans epoxides, independent of syn or anti relation of the two epoxides. In the cis series, Sb(III) pnictogen-bonding catalysts afford BA products almost exclusively for syn diastereomers, while anti diastereomers give equal amounts of BA and AB products. Sb(V) pnictogen-bonding catalysts show similarly special trends. These unique characteristics support that pnictogen-bonding catalysis differs from Lewis acid catalysis and can arguably be defined as its non-covalent counterpart, just like hydrogen-bonding catalysis is understood and appreciated as the noncovalent counterpart of Brønsted acid catalysis. Computational studies on the origin of anti-Baldwin selectivity reveal Sb(V) catalysts with an introvert deep σ hole surrounded by an almost planar ring of ligands. Central pnictogen-bond attraction against peripheral steric repulsion then forces the epoxide to break open. In contrast, transient antimony oxidation in cyclic intermediates accounts for the chemoselectivity of Sb(III) catalysts. Presumably due to insufficient accessibility of their σ holes, the activity of tetrel-bonding catalysts is negligible. The division between powerful pnictogen-bonding and irrelevant tetrel-bonding catalysts does not exist with the respective orthodox Lewis acids and thus supports that σ-hole and Lewis acid catalysis are not the same.

The autocatalysis of epoxide-opening ether cyclizations on the aromatic surface of anion−π catalysts stands out as a leading example of emergent properties expected from the integration of unorthodox interactions into catalysis. A working hypothesis was proposed early on, but the mechanism of anion−π autocatalysis has never been elucidated. Here, we show that anion−π autocatalysis is almost independent of peripheral crowding in substrate and product. Inaccessible asymmetric anion−π autocatalysis and sometimes erratic reproducibility further support that the origin of anion−π autocatalysis is more complex than originally assumed. The apparent long-distance communication without physical contact calls for the inclusion of water between substrate and product on the catalytic aromatic surface. Efficient anion−π autocatalysis around equimolar amounts but poor activity in dry solvents and with excess water indicate that this inclusion of water requires high precision. Computational models suggest that two water molecules transmit dual substrate activation by the product and serve as proton shuttles along antiparallel but decoupled hydrogen-bonded chains to delocalize and stabilize evolving charge density in the transition state by "anion−π double bonds". This new transition-state model of anion−π autocatalysis provides a plausible mechanism that explains experimental results and brings anion−π catalysis to an unprecedented level of sophistication.

Anion‐π catalysis operates by stabilizing anionic transition states on π‐acidic aromatic surfaces. In anion‐(π)n‐π catalysis, π stacks add polarizability to strengthen interactions. In search of synthetic methods to extend π stacks beyond the limits of foldamers, the self‐assembly of micelles from amphiphilic naphthalenediimides (NDIs) is introduced. To interface substrates and catalysts, chargetransfer complexes with dialkoxynaphthalenes (DANs), a classic in supramolecular chemistry, are installed. In π‐stacked micelles, the rates of bioinspired ether cyclizations exceed rates on monomers in organic solvents by far. This is particularly impressive considering that anion‐π catalysis in water has been elusive so far. Increasing rates with increasing π acidity of the micelles evince operational anion‐(π)n‐π catalysis. At maximal π acidity, autocatalytic behavior emerges. Dependence on position and order in confined micellar space promises access to emergent properties. Anion‐(π)n‐π catalytic micelles in water thus expand supramolecular systems catalysis accessible with anion‐π interactions with an inspiring topic of general interest and great perspectives.