The impact of climate change and human activities on endangered plants has been a serious concern in forest ecology. Some Carpinus plants have become extinct. Thus, we need to pay more attention to the Carpinus plants that are not yet extinct but are endangered. Here, we employed the species distribution model (SDM) considering different climate change scenarios and human footprint to test the potential habitat changes of three Carpinus species (C. oblongifolia, C. tientaiensis, and C. purpurinervis) in the future. Our results showed that the mean diurnal range of temperature (MDRT), isothermality, mean temperature of wettest quarter, and human footprint were the most influential factors determining the distribution of C. oblongifolia. Precipitation seasonality (coefficient of variation), MDRT, and precipitation of driest quarter were the most important climatic factors affecting C. tientaiensis. The minimum temperature of the coldest month was the most important factor in the distribution of C. purpurinervis. Our results also showed that the three species had different adaptability and habitat change trends under the future climate change scenarios, although they belong to the same genus. The potential habitats of C. oblongifolia would expand in the future, while the potential habitats of C. tientaiensis and C. purpurinervis would decrease for the same period. The predicted changes of these three endangered species on temporal and spatial patterns could provide a theoretical basis for their conservation strategies.

Histone acetylation and methylation, governed by various histone modification (HM) gene families, are vital for plant biological processes. However, there are limited studies that have explored HMs in ornamental horticultural trees, including sweet osmanthus (Osmanthus fragrans). We performed genome-wide search and identified 208 OfHMs, encompassing 81 histone methyltransferases (OfHMTs), 51 histone demethylases (OfHDMs), 49 histone acetyltransferases (OfHATs) and 27 histone deacetylases (HDACs). Our comprehensive analysis covered chromosome locations, gene structures, conserved domains, cis-acting elements, phylogenetic comparisons, protein interaction networks and functional enrichment pathways for these gene families. Additionally, tandem and fragment replications were unveiled as contributors to the expansion of OfHMs, with some genes exhibiting positive selection. Furthermore, we examined OfHM expression profiles across various tissues and flowering stages, and under 5′-azacytidine (Aza) and ethylene treatments. Most OfHMs displayed heightened expression in leaves, and were downregulated during the flower opening and senescence stages, including OfPRMTs, OfHDTs, OfHDAs, OfSRTs, OfJMJs and OfHAGs; 75.86% and 80.77% of the differentially expressed OfHMs were upregulated after Aza and ethylene treatments, including OfHAGs, OfHDAs and OfSDGs. This study offers a comprehensive analysis of the OfHM gene family, which indicated their potential involvement in ethylene and Aza responses, and in the flowering process. These findings provide valuable insights into the role of OfHMs in flowering and stress responses.

A key objective of forest tree breeding programs is to enhance traits related to growth and stem form, to cultivate plantations that exhibit rapid growth, straight trunks with minimal taper, and superior wood quality to meet the demands of modern timber production. Notably, Liriodendron species exhibit notable heterosis in interspecies hybrids, with hybrid Liriodendron displaying rapid growth rates, straight trunks, and wide adaptability. However, the genetic architecture underlying growth and stem form traits remains unclear, hindering the progress of genetic improvement efforts. Genome-wide association study (GWAS) emerges as an effective approach for identifying target genes and clarifying genetic architectures. In this study, a comprehensive analysis was conducted using an artificial population of 233 hybrid progeny derived from 25 hybrid combinations and resequenced to obtain genome-wide single nucleotide polymorphism (SNP) and insertion and deletion (InDel) variants. After filtering, a total of 192,972 SNP loci and 60,666 InDel loci were obtained, which were subsequently analyzed for associations using the R package GAPIT. We identified 97 significant SNP loci and 58 significant InDel loci (−Log₁₀(P) ≥ 4.50), respectively, culminating in the identification of 161 candidate genes. The functions of these candidate genes were annotated, revealing potential associations between Lchi_2g03172 and Lchi_10g19986 genes with the growth of hybrid Liriodendron, and highlighting the potential influence of the Lchi_16g30522 gene on the growth and branching of hybrid Liriodendron. Overall, this study serves as a foundational step towards unraveling the genetic architecture underpinning growth and stem form in Liriodendron plants.

Introduction: The vascular cambium is a pivotal tissue that drives secondary growth in woody plants, directly determining wood structure and properties. Schima superba , a valuable timber species in China, holds considerable ecological and economic importance. However, the seasonal activity of its cambium remains poorly understood. Methods: To elucidate the underlying molecular and metabolic regulatory mechanisms, we integrated untargeted metabolomics, lignin-targeted metabolomics, and transcriptomic analyses. Results: Untargeted metabolomic profiling identified 2,178 differentially synthesised metabolites (DSMs), predominantly associated with amino acid metabolism, fatty acid metabolism, phenylpropanoid biosynthesis (PB), and plant hormone signal transduction (PHST). Lignin-targeted metabolomics detected 8 DSMs, most of which initially increased and subsequently declined, peaking in August, with the exception of sinapyl alcohol and L-phenylalanine. Transcriptomic analysis identified 19,609 differentially expressed genes (DEGs), primarily enriched in PB and PHST pathways. Key PB-related structural genes, including SsPAL , SsC4H , Ss4CL , SsCOMT , and SsCAD , exhibited peak expression during the cambial active period, correlating with lignin intermediate accumulation and indicating tight coordination between transcriptional activity and metabolic flux during lignification. PHST-related genes involved in auxin (AUX), cytokinin (CTK), and gibberellin (GA) signalling, such as SsARF , SsSAUR , and SsARR-B , displayed stage-specific expression patterns regulating cambial cell expansion and division. Weighted gene coexpression network analysis (WGCNA) further identified core transcription factors, including SsMYB , SsbHLH , SsWOX , SsGRAS , SsSAUR , and SsNF-YB , as regulators of seasonal cambial activity. Discussion: These findings provide a comprehensive framework for understanding seasonal cambial activity in S. superba , and offer valuable insights into the regulatory mechanisms of vascular cambium activity in woody plants, thereby supporting targeted wood quality improvement and advancing our understanding of plant developmental biology.