Despite the growing resources and tools for high-throughput characterization and analysis of genomic information, the discovery of the genetic elements that regulate complex traits remains a challenge. Systems genetics is an emerging field that aims to understand the flow of biological information that underlies complex traits from genotype to phenotype. In this study, we used a systems genetics approach to identify and evaluate regulators of the lignin biosynthesis pathway in Populus deltoides by combining genome, transcriptome, and phenotype data from a population of 268 unrelated individuals of P. deltoides. The discovery of lignin regulators began with the quantitative genetic analysis of the xylem transcriptome and resulted in the detection of 6706 and 4628 significant local- and distant-eQTL associations, respectively. Among the locally regulated genes, we identified the R2R3-MYB transcription factor MYB125 (Potri.003G114100) as a putative trans-regulator of the majority of genes in the lignin biosynthesis pathway. The expression of MYB125 in a diverse population positively correlated with lignin content. Furthermore, overexpression of MYB125 in transgenic poplar resulted in increased lignin content, as well as altered expression of genes in the lignin biosynthesis pathway. Altogether, our findings indicate that MYB125 is involved in the control of a transcriptional coexpression network of lignin biosynthesis genes during secondary cell wall formation in P. deltoides.

中文翻译：

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木质部系统遗传学分析揭示了三角杨木质素生物合成的关键调节因子。

尽管用于高通量表征和基因组信息分析的资源和工具不断增加，但发现调节复杂性状的遗传元件仍然是一个挑战。系统遗传学是一个新兴领域，旨在了解从基因型到表型的复杂特征背后的生物信息流。在这项研究中，我们使用系统遗传学方法通过结合来自 268 个不相关的三角杨个体的基因组、转录组和表型数据来识别和评估三角杨木质素生物合成途径的调节因子. 木质素调节因子的发现始于木质部转录组的定量遗传分析，并分别检测到 6706 和 4628 个显着的局部和远距离 eQTL 关联。在局部调节的基因中，我们将 R2R3-MYB 转录因子MYB125 ( Potri.003G114100 )鉴定为木质素生物合成途径中大多数基因的推定反式调节因子。的表达MYB125在不同的人口与木质素含量正相关。此外，MYB125 的过表达在转基因杨树中导致木质素含量增加，以及木质素生物合成途径中基因表达的改变。总而言之，我们的研究结果表明MYB125参与了P. deltoides次生细胞壁形成过程中木质素生物合成基因转录共表达网络的控制。