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Oleaceae, a eudicot family with great species diversity, has attracted much attention from botanists because it contains many plants with important economic, medicinal, and ornamental values. However, the history of polyploidization and ancestral genome reshuffling of Oleaceae remains unclear. Here, we clarified an Oleaceae‐common hexaploidization (OCH) event occurring at ~53–61 million years ago (Ma) common in all Oleaceae plants and an Oleaceae‐recent tetraploidization (ORT) event occurring at ~18–21 Ma shared by the lineages of Syringa, Olea, Osmanthus, and Fraxinus. We found that high‐frequency polyploidization events drove the frequency of gene loss in Oleaceae genomes and extended the size of regions containing adjacent gene loss, thereby promoting the degree of genome fragmentation. We revealed that biased fractionation between the OCH‐ and ORT‐produced subgenomes is likely attributed to the origin of allopolyploidization in the OCH and ORT events. Significantly, through paleochromosome rearrangement comparisons, we proposed a "two‐step" genome duplication model for OCH and determined the duplicated orders of OCH tripled genome. We reconstructed 11 protochromosomes of the most recent ancestral Oleaceae karyotype (AOK) and elucidated the trajectories of immense paleochromosome reorganization of Oleaceae species from ancestral eudicot karyotype. Notably, we tracked the diversification history of secondary metabolite synthesis genes in the Oleaceae and explored the effects of paleogenome evolution on specialized metabolite synthesis. Our findings provide new insights into the polyploidization and paleogenomic evolution of Oleaceae and have important scientific significance for understanding the genetic basis of species and secondary metabolic diversity in Oleaceae. [ABSTRACT FROM AUTHOR]

Developing cost-effective and sustainable catalysts with exceptional activity and selectivity is essential for the practical implementation of on-site H 2 O 2 electrosynthesis, yet it remains a formidable challenge. Metal phosphide core-shell heterostructures anchored in carbon nanosheets (denoted as Ni@Ni 2 P/C NSs) are designed and synthesized via carbonization and phosphidation of the 2D Ni-BDC precursor. This core-shell nanostructure provides more accessible active sites and enhanced durability, while the 2D carbon nanosheet substrate prevents heterostructure aggregation and facilitates mass transfer. Theoretical calculations further reveal that the Ni/Ni 2 P heterostructure-induced optimization of geometric and electronic structures enables the favored adsorption of OOH * intermediate. All these features endow the Ni@Ni 2 P/C NSs with remarkable performance in 2e ORR for H 2 O 2 synthesis, achieving a top yield rate of 95.6 mg L -1  h -1 with both selectivity and Faradaic efficiency exceeding 90% under a wide range of applied potentials. Furthermore, when utilized as the anode of an assembled gas diffusion electrode (GDE) device, the Ni@Ni 2 P/C NSs achieve in situ H 2 O 2 production with excellent long-term durability (>32 h). Evidently, this work provides a unique insight into the origin of 2e ORR and proposes optimization of H 2 O 2 production through nano-interface manipulation., (© 2024 Wiley‐VCH GmbH.)