Zhong Shanchen, Zhang Weixi, Ding Changjun, Yuan Zhengsai, Shen Le, Zhang Bingyu, Chu Yanguang, Su Xiaohua
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China.
Int J Mol Sci. 2025 Jun 9;26(12):5526. doi: 10.3390/ijms26125526.
Enhancing stress tolerance represents a critical objective in the genetic improvement of poplar trees. × 'Bofeng 3' is a nationally certified elite poplar variety that was approved as a premium pulpwood variety for the southern area of Northeastern China. This variety grows quickly, has good yield, and resists frost; however, its weaker drought and salt tolerance limits its broader use in diverse environments. The aim of this study is to understand the genetic basis of the fast growth and stress-adaptation traits of this variety and to provide support for future molecular breeding efforts. We present a chromosome-scale genome assembly of × 'Bofeng 3', totaling 445.53 Mb, of which with 90.39% is anchored to 19 chromosomes, containing 33,309 protein-coding genes and 45.36% repetitive elements. Comparative genomics showed that 'Bofeng 3' has expanded gene families related to photosynthesis and metabolism, and contracted families involved in stress responses, distinguishing it from other species. Under drought (9137 leaf, 9403 root differentially expressed genes (DEGs)) and salt stress (2840 leaf, 3807 root DEGs), trend analysis revealed specific expression patterns. Several unique and expanded genes, including those for photosynthetic proteins, peroxidases, gamma-aminobutyric acid metabolism, and disease resistance, showed stress-responsive trends. Weighted gene co-expression network analysis identified five modules (three positive, two negative) that significantly correlated with photosynthetic traits, highlighting key candidates such as bZIP transcription factors and auxin/indole acetic acid genes. This study determined the genetic basis underlying the rapid growth traits of × 'Bofeng 3', while providing genomic resources to establish a robust foundation for future gene editing and molecular breeding studies, including critical candidate genetic resources for developing superior drought- and salt-tolerant poplar varieties via targeted genome editing technologies.
提高胁迫耐受性是杨树遗传改良的一个关键目标。ב博丰3号’是一个国家级认证的优良杨树品种，被批准为中国东北地区南部的优质纸浆材品种。该品种生长迅速，产量高，抗霜冻；然而，其较弱的耐旱性和耐盐性限制了它在不同环境中的更广泛应用。本研究的目的是了解该品种快速生长和胁迫适应性状的遗传基础，并为未来的分子育种工作提供支持。我们展示了ב博丰3号’的染色体水平基因组组装，总计445.53 Mb，其中90.39%锚定在19条染色体上，包含33309个蛋白质编码基因和45.36%的重复元件。比较基因组学表明，‘博丰3号’具有与光合作用和代谢相关的基因家族扩张，以及参与胁迫反应的基因家族收缩，这使其与其他物种有所区别。在干旱（9137个叶片、9403个根系差异表达基因（DEGs））和盐胁迫（2840个叶片、3807个根系DEGs）条件下，趋势分析揭示了特定的表达模式。几个独特且扩张的基因，包括光合蛋白、过氧化物酶、γ-氨基丁酸代谢和抗病相关基因，呈现出胁迫响应趋势。加权基因共表达网络分析确定了五个与光合性状显著相关的模块（三个正相关、两个负相关），突出了关键候选基因，如bZIP转录因子和生长素/吲哚乙酸基因。本研究确定了ב博丰3号’快速生长性状的遗传基础，同时提供了基因组资源，为未来的基因编辑和分子育种研究奠定了坚实基础，包括通过靶向基因组编辑技术培育优良耐旱和耐盐杨树品种的关键候选遗传资源。
