Table_3_Novel candidate genes for lignin structure identified through genome-wide association study of naturally varying Populus trichocarpa.xlsx

Populus is a promising lignocellulosic feedstock for biofuels and bioproducts. However, the cell wall biopolymer lignin is a major barrier in conversion of biomass to biofuels. To investigate the variability and underlying genetic basis of the complex structure of lignin, a population of 409 three-year-old, naturally varying Populus trichocarpa genotypes were characterized by heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR). A subsequent genome-wide association study (GWAS) was conducted using approximately 8.3 million single nucleotide polymorphisms (SNPs), which identified 756 genes that were significantly associated (−log10(p-value)>6) with at least one lignin phenotype. Several promising candidate genes were identified, many of which have not previously been reported to be associated with lignin or cell wall biosynthesis. These results provide a resource for gaining insights into the molecular mechanisms of lignin biosynthesis and new targets for future genetic improvement in poplar.

杨属（Populus）是极具应用潜力的木质纤维素原料，可用于制备生物燃料与生物基产品。然而，细胞壁生物聚合物木质素是生物质转化为生物燃料的主要障碍。为探究木质素复杂结构的变异特性及其潜在遗传基础，研究团队对409份3年生、自然变异的毛果杨（Populus trichocarpa）基因型材料开展了异核单量子相干（HSQC）核磁共振（NMR）表征。后续基于约830万个单核苷酸多态性（SNPs）开展全基因组关联分析（GWAS），鉴定出756个与至少一种木质素表型显著相关的基因（-log₁₀(p值)>6）。本研究筛选得到多个极具潜力的候选基因，其中多数此前未被报道与木质素代谢或细胞壁生物合成存在关联。上述研究结果为解析木质素生物合成的分子机制提供了重要参考资源，同时为未来杨属植物的遗传改良提供了全新靶点。