Qin Shuangshuang, Liang Ying, Wei Guili, Wei Fan, Wei Kunhua, Chen Xiaoying
Guangxi Key Laboratory of Medicinal Resources Protection and Genetic Improvement/Guangxi Engineering Research Center of TCM Resource Intelligent Creation, National Center for TCM Inheritance and Innovation, Guangxi Botanical Garden of Medicinal Plants, Nanning 530023, China.
Heliyon. 2024 Mar 12;10(6):e28077. doi: 10.1016/j.heliyon.2024.e28077. eCollection 2024 Mar 30.
The medicinal plant Dunn is easily exposed to shade stress during growth, but its shade responses and shade stress resistant mechanisms have not been clarified. In this study, shade treatments including four attenuated sunlight intensities (100%, 60%, 40%, and 10%) and three shade durations (30 d, 45 d, and 60 d) were applied to . The shade-induced morphological indicators, phytohormonal regulations, metabolic flavonoids contents, transcriptomic flavonoid pathway gene expressions, and stress physiological changes of were analyzed. The putative promoter -regulatory elements (CREs) of 18 flavonoid biosynthetic pathway genes were identified. Results showed the stem growth indicators of were better at 40% light intensity. Phytohormones were involved in the shade-induced responses. Short-term shade (30 d) increased total flavonoids, gallated catechins and especially epigallocatechin gallate contents and favored for boosting medicinal value. Long-term shade (45 d, 60 d) tended to decrease flavonoids. The shade-induced flavonoids changes were attributed to their corresponding biosynthesizing genes expression variations. The high antioxidant capacity and the presence of phytohormone-, stress-, and development-related CREs provided the basis for stress resistance. In conclusion, the multiple responses under shade and the CREs analysis elucidated ' shade tolerance.
药用植物Dunn在生长过程中容易受到遮荫胁迫，但其遮荫响应和耐遮荫胁迫机制尚未明确。在本研究中，对其施加了包括四种减弱光照强度（100%、60%、40%和10%）和三种遮荫持续时间（30天、45天和60天）的遮荫处理。分析了遮荫诱导的形态指标、植物激素调节、代谢类黄酮含量、转录组类黄酮途径基因表达以及Dunn的胁迫生理变化。鉴定了18个类黄酮生物合成途径基因的推定启动子调控元件（CREs）。结果表明，在40%光照强度下，Dunn的茎生长指标更好。植物激素参与了遮荫诱导的反应。短期遮荫（30天）增加了总黄酮、没食子酰儿茶素尤其是表没食子儿茶素没食子酸酯的含量，有利于提高药用价值。长期遮荫（45天、60天）则倾向于降低类黄酮含量。遮荫诱导的类黄酮变化归因于其相应生物合成基因的表达变化。高抗氧化能力以及植物激素、胁迫和发育相关CREs的存在为抗胁迫提供了基础。总之，遮荫下的多种反应以及CREs分析阐明了Dunn的耐荫性。
