Convergent adaptation of the genomes of woody plants at the land-sea interface

Sequencing multiple species that share the same ecological niche may be a new frontier for genomic studies. While such studies should shed light on molecular convergence, genomic-level analyses have been unsuccessful, due mainly to the absence of empirical controls. Woody plant species that colonized the global tropical coasts, collectively referred to as mangroves, are ideal for convergence studies. Here, we sequenced the genomes/transcriptomes of 16 species belonging in three major mangrove clades. To detect convergence in a large phylogeny, a CCS+ model is implemented, extending the more limited CCS method (convergence at conservative sites). Using the empirical control for reference, the CCS+ model reduces the noises drastically, thus permitting the identification of 73 convergent genes with P-true (probability of true convergence) > 0.9. Products of the convergent genes tend to be on the plasma membrane associated with salinity tolerance. Importantly, convergence is more often manifested at a higher level than at amino-acid (AA) sites. Relative to >50 plant species, mangroves strongly prefer 4 AAs and avoid 5 others across the genome. AA substitutions between mangrove species strongly reflect these tendencies. In conclusion, the selection of taxa, the number of species and, in particular, the empirical control are all crucial for detecting genome-wide convergence. We believe this large study of mangroves is the first successful attempt at detecting genome-wide site convergence

How Distributed Leadership Fosters Individual Leadership Emergence: The Mediating Role of Empowerment Role Identity and Enacted Leader Identity

Departing from past research on managers’ influence on employees’ informal leadership emergence, we explore the mechanism of how distributed leadership enhances individual leadership emergence from a cognitive perspective. Drawing upon the leadership identity construction theory and role identity theory, we theoretically developed and empirically tested a serial mediation model. It examines how distributed leadership promotes employees’ leadership emergence via individual empowerment role identity and enacted leader identity. Using a three-wave field survey from 496 subordinate–supervisor dyads (82 supervisors and 496 employees) in China, we found that empowerment role identity and enacted leader identity serially mediate the association between distributed leadership and employees’ leadership emergence. The results demonstrate the leadership identity construction process of employees’ leadership emergence under distributed leadership. The theoretical and practical implications of our findings are then discussed

Imaging-based intelligent spectrometer on a plasmonic rainbow chip

The authors develop an imaging-based intelligent spectrometer on a plasmonic “rainbow” chip. It can accurately and precisely determine the spectroscopic and polarimetric information of the illumination spectrum using a single image assisted by suitably trained deep learning algorithms

Chemical design and synthesis of superior single-atom electrocatalysts via in situ polymerization

Molecule-like electrocatalysts with FeN4motifs have been demonstrated to be excellent candidates for various renewable energy conversions. The ability to further tune the electronic properties of molecular FeN4motifs and integrate them onto conductive supports represents a key step towards the synthesis of highly robust and efficient single-atom catalysts (SACs) for practical applications. Here, we developed a new route for the synthesis of a well-defined single-atom FeN4electrocatalystvia in situpolymerization of four amino groups functionalized iron phthalocyanine (NH2-FePc) molecules on conductive carbon nanotubes. The intermolecular oxidative dimerization between the amino groups of NH2-FePc creates the desired electron-withdrawing pyrazine linker between FeN4motifs, which can significantly optimize their electrocatalytic performances. As a result, the FeN4-SAC exhibits both outstanding ORR activity (a half-wave potential of 0.88 Vvs.RHE) and excellent performance in Zn-oxygen batteries, outperforming the commercial Pt/C and pristine iron phthalocyanine (FePc) catalysts. Our theoretical calculations reveal that the presence of electron-withdrawing linkers shifts the occupied antibonding states towards lower energies and thus weakens the Fe-O bond, which is primarily responsible for the enhancement of ORR activity.</p

The origin, diversification and adaptation of a major mangrove clade (Rhizophoreae) revealed by whole-genome sequencing

Mangroves invade some very marginal habitats for woody plants-at the interface between land and sea. Since mangroves anchor tropical coastal communities globally, their origin, diversification and adaptation are of scientific significance, particularly at a time of global climate change. In this study, a combination of single-molecule long reads and the more conventional short reads are generated from Rhizophora apiculata for the de novo assembly of its genome to a near chromosome level. The longest scaffold, N50 and N90 for the R. apiculata genome, are 13.3Mb, 5.4Mb and 1.0Mb, respectively. Short reads for the genomes and transcriptomes of eight related species are also generated. We find that the ancestor of Rhizophoreae experienced a whole-genome duplication similar to 70 Myrs ago, which is followed rather quickly by colonization and species diversification. Mangroves exhibit pan-exomemodifications of amino acid (AA) usage as well as unusual AA substitutions among closely related species. The usage and substitution of AAs, unique among plants surveyed, is correlated with the rapid evolution of proteins in mangroves. A small subset of these substitutions is associated with mangroves' highly specialized traits (vivipary and red bark) thought to be adaptive in the intertidal habitats. Despite the many adaptive features, mangroves are among the least genetically diverse plants, likely the result of continual habitat turnovers caused by repeated rises and falls of sea level in the geologically recent past. Mangrove genomes thus inform about their past evolutionary success as well as portend a possibly difficult future