Salt stress is one of the major environmental factors affecting plant growth and productivity. BRI1-EMS suppressor 1/brassinazole-resistant 1 ((BES1/BZR1) plays an important role in responding to abiotic stress in plants. Although the impacts of BES1/BZR1 on plant growth and resistance have been documented, the potential mechanisms are not fully elucidated in Betula platyphylla. This work contributes to the understanding of how BES1/BZR1 promotes stress tolerance in woody plants. Six BES1/BZR1 family members were identified from Betula platyphylla. Cis-element analysis showed that the promoters of six genes were rich in ABA-responsive element (ABRE), MYB and MBS cis-acting elements, which are reported to be involved in abiotic stress responses. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that BpBZR1-6 (BPChr10G06000) could be induced by salt stress, ABA and BRs. BpBZR1-6 was localized in the nucleus and had transactivation activity. Ectopic expression of BpBZR1-6 enhanced Arabidopsis tolerance and decreased abscisic acid (ABA) sensitivity under salt treatment. Specifically, the seed germination rate, root length, fresh weight and chlorophyll content were significantly higher in BpBZR1-6-overexpressing (OE) transgenic plants than in wild-type (WT) plants after salt stress (P < 0.05). Additionally, BpBZR1-6 overexpression showed enhanced the reactive oxygen species (ROS) scavenging capability under salt stress, including increasing the activities of antioxidant enzyme, resulting in a decrease in O2− and H2O2 accumulation, and reducing malondialdehyde (MDA) content. Meanwhile, the expression levels of six antioxidant enzyme genes were higher in OE plants than in WT plants after stress. BpBZR1-6 overexpression enhanced the salt tolerance of transgenic plants by modulating antioxidant enzyme gene expression and ROS scavenging, which may provide underlying strategy for breeding of salt-tolerant plants.

In the context of global climate change and efforts toward “carbon peak and carbon neutrality,” forest resource protection and restoration have become fundamental to ecological civilization. The genetic improvement of trees, as the primary component of forest ecosystems, holds strategic importance for ecological security, resource supply, and carbon neutrality. Traditional tree breeding techniques, including selective and hybrid breeding, have established robust technical systems through extensive practice. However, these methods face limitations such as extended cycles, reduced efficiency, and constrained genetic gains in meeting contemporary requirements. Modern biotechnologies, including genomic selection (GS), gene editing (CRISPR/Cas9), and marker-assisted selection (MAS), substantially enhance the precision and efficiency of genetic improvement. Nevertheless, exclusive reliance on either traditional or modern methods proves insufficient for addressing complex environmental adaptation and rapid breeding requirements. Consequently, the integration of traditional breeding with modern biotechnology to develop intelligent, sustainable, and efficient breeding strategies has emerged as a central focus in tree genetics and breeding. An integrated “step-by-step” approach warrants promotion, supported by a multi-source data sharing platform, an optimized core germplasm repository, and a “climate-soil-genotype” matching model to facilitate the region-specific deployment of improved varieties.

Low temperature is a major stress that severely affects tree growth and development. Despite the fact that the molecular mechanisms behind cold tolerance and associated regulatory networks in these trees remain largely unexplored, we conducted a study to examine the overall changes in metabolites and regulatory pathways of Populus ussuriensis kom. when exposed to cold stress, utilizing a comprehensive multi-omics approach. Transcriptomes exposed to cold stress reveal that most of the candidate genes related to the Calvin–Benson–Bassham cycle and flavonoid synthesis were upregulated. Joint analysis revealed that within 6–48 h of low-temperature treatment, differential genes (such as PAL and CHS) in the flavonoid biosynthesis pathway and metabolites (such as quercetin) were significantly upregulated, indicating a positive correlation under short-term stress. However, prolonged treatment (72 h) may trigger metabolic feedback, leading to a decrease in flavonoid content. In addition, the measurements of gas exchange and metabolite assays of P. ussuriensis showed that photosynthetic acclimation led to a change in the sugar accumulation and starch degradation in response to low temperature, indicating that extensive changes occurred due to the cold and improved tolerance in P. ussuriensis. This study provides a new basis for future studies on the molecular mechanism of cold tolerance at the transcriptional and metabolic levels.

Populus koreana emits a wide array of volatile organic compounds (VOCs) with potential ecological functions; however, the tissue-specific distribution and underlying regulatory mechanisms of these compounds remain poorly understood. This study employed an integrated approach combining gas chromatography-mass spectrometry (GC-MS)-based metabolomics and RNA-seq to systematically profile VOC composition and gene expression in terminal buds, stems and leaves of P. koreana. A total of 207 VOCs were identified, predominantly terpenes and aromatic compounds, exhibiting distinct tissue-specific accumulation patterns. Terminal buds were enriched in limonene and caryophyllene, while leaves showed higher concentrations of alcohols and phenolic aldehydes. Transcriptomic analysis revealed 12,733 differentially expressed genes (DEGs) among the three organs, with substantial enrichment in terpenoid and phenylpropanoid biosynthetic pathways. Notably, key upregulated genes in buds, including TPS21 and PAL1, correlated with observed VOC profiles. Weighted gene co-expression network analysis (WGCNA) further identified 6365 genes strongly associated with bud-specific VOC biosynthesis. Integrated omics analyses indicated coordinated regulation of phenylalanine metabolism and transcription factors in VOC production. These findings illuminate the molecular mechanisms underlying tissue-specific VOC accumulation in P. koreana, enhancing our understanding of metabolic specialization and ecological adaptation in woody plants.