黑果皮高粱由于可生物合成 3-脱氧花青素 (3-DOA) 而具有显着价值，3-脱氧花青素 (3-DOA) 是一类罕见的生物活性多酚，可作为抗氧化食品添加剂和对人类癌细胞具有细胞毒性的生物活性化合物。进行了代谢和转录组学研究，以确定导致黑高粱果皮中 3-DOA 生物合成激活的细胞事件。在谷物成熟过程中，果皮长时间暴露在高通量紫外线 (UV) 下，会导致果皮组织中活性氧 (ROS) 水平升高并激活 3-DOA 生物合成。与 3-DOA 生物合成相关的是早期和晚期类黄酮生物合成途径基因的特定家族成员的转录激活以及防御相关途径的下游激活。与黑果皮中 3-DOA 生物合成高度相关的基因的启动子分析富含 MYB 和 HHO5/ARR-B 基序。黑色果皮组织的光学显微镜研究表明，3-DOA 主要位于外果皮中，并与细胞壁相关。提出了一种紫外线诱导的黑色果皮 3-DOA 生物合成的工作模型，该模型具有与病原体攻击或机械损伤相关的植物免疫特征。本模型描述了 ROS 积累、受体激酶和转录因子 (TF)（包括 NAC、WRKY、bHLH、AP2 和 C2H2 锌指结构域）的转录激活。这项研究确定了黑果皮中 3-DOA 积累的关键生物合成和调控基因，并提供了对控制这种组织和基因型特异性性状的基因网络和细胞事件的更深入的了解。版权所有 © 2024 Schumaker、Mortensen、Klein、Mandal、Dykes 、格拉德曼、鲁尼、博雅和克莱因。

Black pericarp sorghum has notable value due to the biosynthesis of 3-deoxyanthocyanidins (3-DOAs), a rare class of bioactive polyphenols valued as antioxidant food additives and as bioactive compounds with cytotoxicity to human cancer cells. A metabolic and transcriptomic study was conducted to ascertain the cellular events leading to the activation of 3-DOA biosynthesis in black sorghum pericarp. Prolonged exposure of pericarp during grain maturation to high-fluence ultraviolet (UV) light resulted in elevated levels of reactive oxygen species (ROS) and the activation of 3-DOA biosynthesis in pericarp tissues. In conjunction with 3-DOA biosynthesis was the transcriptional activation of specific family members of early and late flavonoid biosynthesis pathway genes as well as the downstream activation of defense-related pathways. Promoter analysis of genes highly correlated with 3-DOA biosynthesis in black pericarp were enriched in MYB and HHO5/ARR-B motifs. Light microscopy studies of black pericarp tissues suggest that 3-DOAs are predominantly localized in the epicarp and are associated with the cell wall. A working model of UV-induced 3-DOA biosynthesis in black pericarp is proposed that shares features of plant immunity associated with pathogen attack or mechanical wounding. The present model depicts ROS accumulation, the transcriptional activation of receptor kinases and transcription factors (TFs) including NAC, WRKY, bHLH, AP2, and C2H2 Zinc finger domain. This study identified key biosynthetic and regulatory genes of 3-DOA accumulation in black pericarp and provided a deeper understanding of the gene networks and cellular events controlling this tissue-and genotype-specific trait.Copyright © 2024 Schumaker, Mortensen, Klein, Mandal, Dykes, Gladman, Rooney, Burson and Klein.