Forestry research最新文献

{"title":"Molecular regulatory mechanisms of <i>Populus deltoides</i> under combined high temperature and short-photoperiod stress associated with DNA methylation.","authors":"Zheng-Sai Yuan, Wei-Xi Zhang, Xiao-Hua Su, Zheng-Hong Li, Jing Zhang, Lu-Lan Miao, Hang Wei, Zi-Hao Wang, Yan-Guang Chu, Chang-Jun Ding","doi":"10.48130/forres-0026-0025","DOIUrl":"10.48130/forres-0026-0025","url":null,"abstract":"<p><p><i>Populus deltoides</i> is a key species for industrial timber and ecological construction in temperate regions, where increasingly frequent and persistent heat waves pose serious challenges to its survival. However, the epigenetic mechanisms by which DNA methylation regulates environmental responses remain poorly understood. Here, whole-genome bisulfite sequencing and RNA-seq were performed on five <i>P. deltoides</i> genotypes grown in temperate and tropical regions. Results revealed that CG/CHG methylation stability is closely correlated with environmental sensitivity. Significant CG/CHG methylation variations may occur specifically in sensitive genotypes with large provenance-environment differences, thereby threatening the survival of <i>P. deltoides</i> by inhibiting the expression of key genes involved in life processes. CHH methylation variation may act as a potential epigenetic regulator of environmental adaptation. Promoter CHH-hypermethylation appears to represent a general response of <i>P. deltoides</i> under high-temperature and short-photoperiod (HS) stress, potentially regulating the expression of 56 genes to activate Ca²⁺ influx and heat shock proteins, repressing auxin, cytokinin, and cell cycle pathways, thereby initiating stress-protective responses. <i>PdeCNGC13</i>, <i>PdeARF6</i>, <i>PdeLOG3,</i> and <i>PdeHSP15.7</i> were identified as potential regulatory genes of HS adaptation that are associated with DNA methylation. The mechanism of <i>PdeLOG3</i> may involve HS-induced CHH-hypermethylation at its <i>PdeLOG3</i> promoter, which may be associated with suppressed expression, reduced dihydrozeatin levels, and growth. This effect was partially reversed by 5-Azacytidine administration, accompanying increased cytokinin synthesis, enhanced antioxidant capacity, and coinciding with alleviation of HS stress. Our work preliminarily reveals the molecular mechanisms underlying DNA methylation-associated environmental adaptation in poplar, providing potential genetic targets for breeding climate-resilient trees.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e025"},"PeriodicalIF":4.8,"publicationDate":"2026-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447283/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Divergence in isoprenoid emissions among subtropical broadleaf trees: linking photosynthesis, leaf economics, and volatile defense for forest management.","authors":"Yimiao Mao, Hang Yao, Yali Yuan, Chao Yu, Meiling Wang, Fei Ding, Guomo Zhou, Zhihong Sun","doi":"10.48130/forres-0026-0023","DOIUrl":"10.48130/forres-0026-0023","url":null,"abstract":"<p><p>Biogenic volatile organic compound (BVOC) emissions are pivotal in plant-environment interactions, yet their intrinsic linkages with photosynthesis and leaf economics across diverse tree species remain poorly integrated. This study investigated seven subtropical broadleaf species spanning distinct lineages to unravel how BVOC chemotypes (isoprene- vs. monoterpene-dominance) align with photosynthetic energy use and leaf structural traits. Using controlled measurements on excised branches to isolate physiological relationships, we combined TD-GC-MS, gas-exchange, and leaf trait analyses. The results revealed strong divergence in BVOC chemotypes that was broadly coherent with species phylogeny and ecological strategy. Isoprene-dominant (ISO) species exhibited higher photosynthetic rates (<i>A</i>), greater electron transport capacity (<i>J</i> _max), and elevated <i>J</i> _max/<i>V</i> _cmax ratios, consistent with the hypothesis that isoprene synthesis functions as a photosynthetic overflow mechanism for energy dissipation. In contrast, monoterpene-dominant (MTS) species displayed higher specific leaf weight (SLW) and relied on stored and induced emissions, reflecting a conservative, defense-oriented strategy. BVOC profiles were strongly correlated with SLW and photosynthetic capacity, highlighting a coordinated 'structure-function-volatile' adaptive syndrome. These findings suggest that BVOC emissions may be embedded within leaf economic strategies and photosynthetic networks, providing a basis to help refine next-generation BVOC models by integrating leaf structural traits (e.g., SLW) and photosynthetic electron transport capacity (<i>J</i> _max) into model parameterization.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e024"},"PeriodicalIF":4.8,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447279/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil pathogens shift root strategies from acquisition to defense under shaded understorey conditions in <i>Pinus koraiensis</i> seedlings.","authors":"Lulu Xie, Xiaohan Li, Xiulong Zhang, Jinguo Wang, Dapao Yu, Qing-Wei Wang","doi":"10.48130/forres-0026-0024","DOIUrl":"10.48130/forres-0026-0024","url":null,"abstract":"<p><p>Broadleaved Korean pine forest, a typical zonal vegetation type in Northeastern China, is important in maintaining regional ecological security. However, the regeneration of Korean pine (<i>Pinus koraiensis</i>) seedlings remains a major constraint in the primary forests. Although declining light availability and increasing soil pathogens are recognized as critical factors affecting seedling survival and growth, their interactive effects and underlying mechanisms remain unclear. In this study, we conducted a controlled experiment with three light levels (200, 400, and 600 μmol·m^-2·s^-1) and four soil pathogen concentrations (0, 1 × 10⁴, 1 × 10⁶, and 1 × 10⁸ CFU/mL) to examine seedling survival, growth, physiology, and above- and belowground functional traits. Low light significantly reduced survival, relative growth rate, photosynthesis, and biomass of <i>P. koraiensis</i> seedlings, while the presence of high pathogen concentrations exacerbated these impacts, notably driving mortality rates up by 95%. Leaf traits were only regulated by light, with shaded conditions increasing specific leaf area and nitrogen (N) concentration, but decreasing total phenolics and carbon/nitrogen ratio. In contrast, root traits were jointly influenced by light and soil pathogens. Under low light, seedlings exhibited an acquisitive strategy characterized by higher specific root length and N concentration, along with reduced root diameter and defense investment. However, increasing pathogen concentration reversed this pattern, suppressing resource acquisition traits while enhancing root diameter and defensive compounds (total phenolics and tannins). These results indicate that light determines the baseline resource context, while soil pathogens impose additional constraints that shift root strategies from resource acquisition to defense. Such interactive regulation modulates seedling establishment, with critical implications for improving forest regeneration and ecosystem stability.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e023"},"PeriodicalIF":4.8,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447282/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"24-nt-phasiRNA associated CHG/CHH DNA methylation contributes to growth heterosis of <i>Populus deltoides</i>.","authors":"Jing Zhang, Weixi Zhang, Changjun Ding, Qi Liu, Zhengsai Yuan, Lulan Miao, Yanguang Chu, Xiaohua Su","doi":"10.48130/forres-0026-0021","DOIUrl":"10.48130/forres-0026-0021","url":null,"abstract":"<p><p>24-nt siRNA-directed DNA methylation is crucial for heterosis in herbaceous plants, but its regulatory function, particularly 24-nt phasiRNA (phased small RNA)-mediated DNA methylation, remains unexplored. This study analyzed whole-genome DNA methylation and small RNA expression between high-growth (H2) and low-growth (L3) <i>Populus deltoides</i> hybrids and their parents, investigating how 24-nt phasiRNA-associated DNA methylation contributes to heterosis. Methylation levels in hybrids and parents ranged from 11.30% to 12.30%, with 22.27% to 23.34% of methylation sites being hybrid-specific. Differentially methylated regions (DMRs) between hybrids and parents mainly originated from similarly methylated regions in parents. Hypo-DMRs were more prevalent in H2, which was the opposite in L3. In the promoter region, expression of differentially methylated genes was correlated with DMR methylation levels between hybrids and parents, albeit exhibiting opposite trends in H2 and L3. Approximately 9% of 24-nt phasiRNAs in hybrids showed additive, dominant, or over-dominant inheritance, with H2 showing paternal bias and L3 maternal bias. 24-nt phasiRNAs were positively correlated with promoter CHG/CHH-DMR methylation levels and negatively correlated with non-additive gene expression, which may facilitate heterosis formation. Gene expression associated with 24-nt phasiRNAs-linked DNA methylation in hybrids was distinctly different, with H2 mainly showing high 24-nt phasiRNA expression, hyper-DMRs, and decreased gene expression, while L3 mainly showed low 24-nt phasiRNA expression, hypo-DMRs, and increased gene expression. We identified 13 candidate 24-nt phasiRNAs and seven key genes, specifically involved in nitrogen response (<i>NLP2/NLP8-like</i>) and photosynthesis (<i>PsbP</i>), which may play an important role in heterosis. This study provides the first evidence of 24-nt phasiRNA-associated DNA methylation in tree heterosis, offering novel insights into epigenetic modifications.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e022"},"PeriodicalIF":4.8,"publicationDate":"2026-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447280/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural innovation under environmental pressure: the evolutionary origins and regulatory mechanisms of thorns.","authors":"Zhe Li, Changhui Tian, Dinghai Zhou, Zhiwen Shi, Lingyan Tan, Yongqing Guo, Yanli Hu, Jihua Mao, Xitong Fei","doi":"10.48130/forres-0026-0020","DOIUrl":"10.48130/forres-0026-0020","url":null,"abstract":"<p><p>Plant thorns represent a prominent evolutionary innovation formed through millions of years of natural selection. However, thorn structures greatly restrict the cultivation and management of many economically important crops, making the breeding of thornless varieties a key objective in modern agricultural breeding. Although different plant species possess apparently similar sharp appendages, these structures originate from different plant organs or tissues. Thorns are not merely mechanical defense structures but are the result of evolutionary adaptations by plants to cope with herbivore pressure and abiotic stresses over evolutionary time. Thorn morphogenesis integrates multiple pathways involved in developmental regulation, defense signaling, and environmental perception, reflecting the resource allocation trade-offs between growth investment and defense efficiency in plants. This review provides a comprehensive synthesis of the developmental origins, anatomical diversity, and ecological defense functions of plant thorns. By integrating paleobotanical evidence, this review traces the evolutionary emergence of thorns during the Paleogene and Neogene periods and reveals the adaptive associations between thorn diversification and the radiation of large herbivorous mammals. At the molecular level, this review focuses on recent advances in developmental genetics, with an emphasis on the regulatory networks underlying thorns' development, as well as the regulatory roles and crosstalk mechanisms of phytohormone signaling pathways involved in defense, including jasmonic acid and gibberellin, in thorns' development. Through a multidisciplinary perspective, this review provides a synthesis of current knowledge on the origin, diversification, and environmental adaptive significance of thorns, providing new insights into the developmental plasticity of plant defense structures.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e021"},"PeriodicalIF":4.8,"publicationDate":"2026-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447285/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tree size and relative height interactions enhance generalized additive models for Chinese fir stem taper prediction.","authors":"Wanrong Chen, Yanjuan Lyu, Xiangrong Wu, Yuhan Wang, Zongming He, Shuaichao Sun","doi":"10.48130/forres-0026-0022","DOIUrl":"10.48130/forres-0026-0022","url":null,"abstract":"<p><p>Tree stem taper varies dynamically with tree size due to biomechanical constraints governing stability, yet capturing this size-dependent shape plasticity remains a challenge in forest biometrics. Traditional variable-exponent models impose rigid functional forms, while emerging machine learning approaches often obscure these biological relationships within black-box structures. Furthermore, previous applications of generalized additive models (GAMs) have predominantly focused on additive effects, overlooking the critical interactions between tree size and relative position along the stem. To address this gap, we investigated whether explicitly modeling the nonlinear interactions between tree size and relative height could resolve systematic biases in taper prediction. Using a dataset of 516 felled Chinese fir (<i>Cunninghamia lanceolata</i>) trees, we constructed GAMs incorporating tensor product interaction smooths and benchmarked them against the widely used parametric models and two machine learning algorithms. We found that GAMs relying solely on main effects failed to outperform the parametric benchmark. However, introducing explicit interaction terms, specifically between diameter at breast height and relative height, substantially reduced the root mean square error by 52.3% compared to the additive GAM and surpassed both the established Kozak-II benchmark and the optimized machine learning models in validation accuracy. Variable importance analysis confirmed that these interactions act as critical modifiers that drive the model improvement by accurately capturing the ontogenetic drift in stem form, such as the pronounced basal flare in larger trees. These findings demonstrate that interaction-inclusive GAMs serve as a powerful tool to bridge the trade-off between algorithmic flexibility and parametric interpretability, offering a biologically grounded approach for precision forest inventory.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e020"},"PeriodicalIF":4.8,"publicationDate":"2026-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447277/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148690723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Telomere-to-telomere assemblies of chromosome 10 reveal complex adaptive variation of 3-ketoacyl-CoA-synthases in <i>Populus trichocarpa</i> likely driven by Helitrons.","authors":"David Kainer, Stanton Martin, Daniel Hopp, Sophie Mosher, Timothy J Tschaplinski, P Doug Hyatt, Madhavi Z Martin, Jared M LeBoldus, Kelsey L Søndreli, Posy E Busby, Mengjun Shu, Kerrie Barry, Jeremy Schmutz, Anna Furches, Nan Zhao, Daniel A Jacobson, Jin-Gui Chen, Mirko Pavicic, Priya Ranjan, Wellington Muchero, Gerald A Tuskan, Michael R Garvin","doi":"10.48130/forres-0026-0019","DOIUrl":"10.48130/forres-0026-0019","url":null,"abstract":"<p><p>The model woody plant <i>Populus trichocarpa</i> displays an atypical alkene-diverse wax cuticle likely driven by copy number variation (CNV) of <i>3-ketoacyl-CoA synthases</i> (<i>KCS</i>), which has been difficult to confirm with short-read assemblies. Long-read sequencing enables the development of telomere-to-telomere resources to detect cryptic variation, including CNVs, which are currently missed. Integrating this information can improve genomic prediction for breeding and provide insights into the evolutionary basis of important traits. Our analysis of 78 long-read haplotypes from chromosome 10 identified more than twice as many <i>KCS</i> genes as previously reported, and numerous intragenic non-synonymous substitutions. Random Forest predictive models highlighted the importance of <i>Potri.010G079500</i> in producing very long chain alkenes; however, its absence did not predict previously reported alkene-deficient phenotypes. Instead, alkene levels are best predicted by the combinations of <i>KCS</i> copies. Additionally, amino acid substitutions clustered around ligand and donor binding pockets, suggesting they contribute to differing wax cuticle composition. Finally, each <i>KCS</i> gene and copy was linked to a Helitron transposon. A phylogenetic analysis suggests Helitrons are the evolutionary mechanism for generating <i>KCS</i> tandem arrays. Long-read generated telomere-to-telomere assemblies of <i>P. trichocarpa</i> chromosome 10 revealed large-effect loci critical to genetic studies that are unattainable from short-reads. This new resource produced novel insights into genome structure and function, and a novel mechanism for generating tandem gene duplication. Our results highlight that, given current challenges in annotation and assembly, detailed and focused long-read sequences are key to interpreting complex genomic regions that contain tandem copy number variants.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e019"},"PeriodicalIF":4.8,"publicationDate":"2026-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13253262/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148255375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydraulic limitation drives differential crown dieback in <i>Populus alba</i> varieties.","authors":"Shu-Dian Liu, Dong-Dong Luo, Geng-Yun Zhao, Yue-Xia Yu, Jun-Tuan Zhai, He Wang, Zhi-Chao Xia, Li-Dong Fang","doi":"10.48130/forres-0026-0017","DOIUrl":"10.48130/forres-0026-0017","url":null,"abstract":"<p><p>The widespread decline and mortality of the Three-North Shelter Forest under climate change is threatening the sustainability of arid and semi-arid ecosystems. As the dominant tree genus in these shelterbelt forests, poplars (<i>Populus</i> spp.) display clear varietal differences in decline patterns, yet the underlying physiological mechanisms remain poorly understood. To address this question, we compared two poplar varieties, <i>Populus alba</i> var. <i>bachofenii</i> (<i>P.b</i>) and <i>Populus alba</i> var. <i>pyramidalis</i> (<i>P.p</i>), using branch samples from upper and lower canopy positions. The results showed that although hydraulic conductivities (<i>K</i> _<i>s</i> and <i>K</i> _<i>l</i> ) did not differ significantly between varieties, <i>P.b</i> consistently exhibited lower percent loss of conductivity (PLC), particularly in the upper canopy branches. In contrast, <i>P.p</i> experienced more negative midday water potentials (<i>Ψ</i> _md) in the upper crown, indicating greater water deficit. Within <i>P.p</i>, declining individuals (<i>P.p-D</i>) displayed higher PLC, whereas hydraulic conductivity, predawn water potential (<i>Ψ</i> _pd), and non-structural carbohydrates (NSC) concentrations were similar to those of healthy trees, indicating that dieback was associated primarily with increased hydraulic vulnerability, rather than reduced transport capacity or carbon depletion. Tree-ring analyses further revealed stable growth in <i>P.b</i>, whereas <i>P.p</i> was more drought-sensitive and showed greater interannual variability. Trees with higher PLC exhibited greater growth sensitivity and reduced radial growth rates, supporting the hydraulic limitation hypothesis. Overall, this study clarifies the physiological mechanisms underlying the contrasting decline patterns among poplar varieties in water-limited regions, and provides guidance for optimizing species selection and management strategies in arid shelterbelts.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e017"},"PeriodicalIF":4.8,"publicationDate":"2026-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13250726/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148230391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracing the Holocene hybrid origin of cultivated walnut in southwestern China.","authors":"Jie Liu, Hai-Ling Qi, Peng-Zhen Fan, Chu-Mei Liu, Zeng-Yuan Wu, Ya-Huang Luo, Richard I Milne, Raees Khan, Lian-Ming Gao, Yue-Hua Wang, Moses C Wambulwa, Robabeh Shahi Shavvon, De-Zhu Li","doi":"10.48130/forres-0026-0018","DOIUrl":"10.48130/forres-0026-0018","url":null,"abstract":"<p><p>Genetic exchanges underpin population adaptation and species evolution. However, knowledge of the genetic impacts of historical, anthropogenic crop-to-wild gene flow remains limited. In southwestern China, the long cultivation and parapatric distribution of <i>Juglans regia</i> and <i>J. sigillata</i> provide an ideal system to investigate this process, yet the evolutionary origin of the cultivated walnut in this region remains a mystery. Using 31 microsatellite loci to genotype 2,866 individuals, along with 716 chloroplast genomes, we evaluated genetic diversity, population structure, and maternal lineage patterns across the region. Population demographic histories were subsequently inferred using approximate Bayesian computation. Our analysis revealed that <i>J. sigillata</i> has higher genetic diversity than <i>J. regia</i>, attributed to its long-term persistence in heterogeneous environments. We observed extensive hybridization between the two species around the Sichuan Basin, forming two geographically distinct subgroups: Hybrid1 in the northwest and Hybrid2 in the south. Both subgroups exhibit variable parental contributions, but with the chloroplast genome entirely introgressed from <i>J. regia</i>. Furthermore, the Sichuan Basin and Yangtze River acted as major geographic barriers to north-south gene flow. Our divergence time estimates showed that the two species diverged during the Pleistocene, followed by an admixture event between <i>J. regia</i> and <i>J. sigillata</i>, forming Hybrid2 during the early Holocene. Subsequent admixture between Hybrid2 and <i>J. regia</i> produced Hybrid1 during the middle Holocene. We propose that cultivated walnuts in southwestern China originated through introgression between <i>J. regia</i> and wild <i>J. sigillata</i> during the Holocene, prior to the introduction of agriculture to the region, a process likely facilitated by historical southward human migrations. This research elucidates how long-term human influence has subtly reshaped the genetic landscape of walnuts in southwestern China through gene flow, providing valuable insights for the study and management of other tree crops.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e018"},"PeriodicalIF":4.8,"publicationDate":"2026-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13253123/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148255416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal genomic patterns of <i>Quercus gilva</i>: decoupling historical isolation from contemporary environmental adaptation.","authors":"Shan-Shan Wang, Tian-Rui Wang, Ling-Ling Wang, Pei-Han Huang, Si-Di Liang, Si-Si Zheng, Liang-Hai Yang, Yu Li, Hong-Hu Meng, Xin Zhong, Xiao-Chen Li, Bin-Jie Ge, Zi-Jia Lu, Yi-Xin Kang, Quan Yuan, Dong-Mei Jin, Xin Ning, Gregor Kozlowski, Young-Jong Jang, Jin Xu, Jung-Hyun Lee, Yi-Gang Song","doi":"10.48130/forres-0026-0016","DOIUrl":"10.48130/forres-0026-0016","url":null,"abstract":"<p><p>The interplay between historical biogeography and environmental selection shapes the genetic architecture of species; however, their relative contributions in widespread and ecologically important tree species remain poorly understood. In the Sino-Japanese Floristic Region, the East China Sea has alternately acted as a barrier and a corridor during glacial-interglacial cycles, influencing species isolation and contact. However, the extent to which these historical dynamics, along with environmental gradients, have driven adaptive evolution in dominant forest trees remains unresolved. In the present study, we integrated phylogeographic reconstruction and landscape genomics based on whole-genome resequencing data from 171 individuals across 35 populations to investigate the evolutionary history and adaptive mechanisms of <i>Quercus gilva</i>, a keystone evergreen oak, in East Asian subtropical forests. Population genomic analyses revealed two deeply divergent genetic groups: the China group and the Japan-Korea group, and demographic modeling indicated that their divergence dates back to the Miocene epoch. The relatively high genomic diversity of <i>Q. gilva</i> may result from the absence of severe genetic bottlenecks throughout its evolutionary history, multiple microrefugia during the glacial periods, and postglacial secondary contact. Notably, Quaternary glacial cycles repeatedly facilitated gene flow and admixture between these groups via exposed land bridges. Landscape genomic analyses further demonstrated that adaptive divergence in <i>Q. gilva</i> is shaped by both geographic isolation and environmental gradients, with annual precipitation emerging as the primary climatic driver. This study provides a genome-wide perspective on how historical biogeography and environmental selection interact to shape the genetic architecture of a dominant subtropical evergreen forest species, offering novel insights into the evolutionary dynamics and adaptive evolution across East Asian biodiversity hotspots.</p>","PeriodicalId":520285,"journal":{"name":"Forestry research","volume":"6 ","pages":"e016"},"PeriodicalIF":4.8,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13195491/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148020280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}