This special issue, Advanced Lightweight Materials and Structures, invited by Chinese Journal of Aeronautics, aims to bring together cutting-edge research and comprehensive reviews that address the data-driven development and evaluation of advanced lightweight materials (e.g. metals and alloys, composites and nanocomposites, coatings and cellular materials) and structures for airframes, aeroengines, helicopters, drones, etc.

Researchers combined forest inventory data, satellite observations, and machine learning to estimate tree density across North America and evaluate the uncertainty of those estimates. The study suggests the continent contains between 339 billion and 514 billion trees with DBH＞10 cm and shows that estimates can vary substantially depending on forest definitions and tree size thresholds. The framework provides a consistent approach for large-scale forest monitoring, biodiversity assessment, and carbon accounting.

Researchers from the University of Georgia and the USDA Forest Service evaluated four strategies for predicting future tree diameters for "unobserved" species. They found that all four strategies can produce reliable predictions. However, approaches that incorporate species-specific information, such as post-hoc calibration using at least one repeated measurement or grouping rare species into an "others" category, tend to provide more precise results. The study offers practical guidance for forest managers working in species-rich tropical forests, where rare and unobserved species are common.

Antibiotic resistance in plant pathogens threatens sustainable crop protection, yet its molecular basis remains incompletely understood. This study reports that streptomycin resistance in Clavibacter michiganensis strain TX-0702 is mediated by a plasmid-borne aminoglycoside phosphotransferase, APH(3), encoded on an uncharacterized plasmid, pCM3. Functional and biochemical analyses demonstrate that APH(3) inactivates streptomycin through phosphorylation, establishing a phosphorylation-driven resistance mechanism in Gram-positive plant pathogens. Sequence analyses reveal that pCM3 carries mobile genetic elements, suggesting environmental dissemination of resistance genes in plant-associated microbes. These findings expand understanding of phytopathogen antibiotic resistance and highlight plant microbiomes as potential resistance gene sources with implications for agricultural, food, and human health safety.