Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163000, China; International Joint Research Center of Agarwood, Haikou 571101, China.
Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
Int J Biol Macromol. 2023 Jul 31;244:125302. doi: 10.1016/j.ijbiomac.2023.125302. Epub 2023 Jun 12.
Trees in the genus Aquilaria produce agarwood, a valuable resin used in medicine, perfumes, and incense. 2-(2-Phenethyl)chromones (PECs) are characteristic components of agarwood; however, molecular mechanisms underlying PEC biosynthesis and regulation remain largely unknown. The R2R3-MYB transcription factors play important regulatory roles in the biosynthesis of various secondary metabolites. In this study, 101 R2R3-MYB genes in Aquilaria sinensis were systematically identified and analyzed at the genome-wide level. Transcriptomic analysis revealed that 19 R2R3-MYB genes were significantly regulated by an agarwood inducer, and showed significant correlations with PEC accumulation. Expression and evolutionary analyses revealed that AsMYB054, a subgroup 4 R2R3-MYB, was negatively correlated with PEC accumulation. AsMYB054 was located in the nucleus and functioned as a transcriptional repressor. Moreover, AsMYB054 could bind to the promoters of the PEC biosynthesis related genes AsPKS02 and AsPKS09, and inhibit their transcriptional activity. These findings suggested that AsMYB054 functions as a negative regulator of PEC biosynthesis via the inhibition of AsPKS02 and AsPKS09 in A. sinensis. Our results provide a comprehensive understanding of the R2R3-MYB subfamily in A. sinensis and lay a foundation for further functional analyses of R2R3-MYB genes in PEC biosynthesis.
沉香树属植物产生沉香，这是一种在医学、香水和香薰中使用的有价值的树脂。2-(2-苯乙基)色酮（PECs）是沉香的特征成分；然而，PECs 生物合成和调节的分子机制在很大程度上仍然未知。R2R3-MYB 转录因子在各种次生代谢物的生物合成中发挥着重要的调节作用。在本研究中，在全基因组水平上系统地鉴定和分析了沉香 101 个 R2R3-MYB 基因。转录组分析显示，19 个 R2R3-MYB 基因被沉香诱导剂显著调控，与 PEC 积累呈显著相关。表达和进化分析表明，AsMYB054，一个亚家族 4 R2R3-MYB，与 PEC 积累呈负相关。AsMYB054 位于细胞核内，作为转录抑制子发挥作用。此外，AsMYB054 可以结合 PEC 生物合成相关基因 AsPKS02 和 AsPKS09 的启动子，并抑制它们的转录活性。这些发现表明，AsMYB054 通过抑制 A. sinensis 中的 AsPKS02 和 AsPKS09，作为 PEC 生物合成的负调控因子发挥作用。我们的研究结果为沉香中 R2R3-MYB 亚家族提供了全面的了解，并为进一步研究 R2R3-MYB 基因在 PEC 生物合成中的功能奠定了基础。
