UV-B辐射增强影响当归生长发育与药效物质代谢的生理和分子机制研究

Ozone depletion in the upper atmosphere causes increasing of UV-B on the earth’s surface, which further influences on terrestrial ecosystems, is one of important ecological problems. We hypothesized that enhanced UV-B radiation in the alpine region could influence on the morphology, resistance acquirement, production and quality formations and medicinal substances metabolism in Chinese angelica, but the exact effect of enhanced UV-B radiation, physiological basis and molecular mechanisms mechanism in Chinese Angelica are still unclear. Based upon the preliminary tests, by the integrating of thoughts and methods of plant physiology, metabonomics, and transcriptomics , to reveal the impacts of enhanced UV-B radiation on plant morphological structure, medicinal materials quality traits and effective medicinal substances accumulation of Chinese angelica; to analyze the characteristics of photosynthetic physiology, antioxidant system, signaling molecules and osmotic regulation, with closely related to growth and development, yield and quality formation of medicinal material, resistance acquiring and effective medicinal substances metabolism of Chinese angelica for clarify physiological nature; and explore efficacy of metabolism related genes and expression difference, parsing efficacy material metabolic network, has proven its molecular mechanism, so as to provide scientific basis for accurately assessing the effects of enhanced UV-B radiation to growth, yield and quality formation, clarifying molecular mechanisms of response of Chinese angelica under enhanced UV B radiation, and revealing effect of enhanced UV-B radiation Chinese angelica quality and its mechanism.

大气平流层臭氧损耗导致到达地表的UV-B辐射增强进而影响陆地生态系统已成为全球关注的重大生态问题之一。UV-B辐射增强可能对高海拔地区栽培当归的形态结构、抗性获得、产量和品质形成、药效物质代谢等也有重要影响，但对其确切影响效应、当归响应的生理学本质和分子机制仍缺乏系统研究。本研究基于前期预研工作，拟综合运用植物生理学、代谢组学、转录组学等的研究思路和手段，研究UV-B辐射增强对当归形态结构、抗性获得、药材产量和质量性状及药效物质积累等影响，揭示其生物效应；探讨与当归产量和质量形成相关的光合生理、对抗氧化系统、信号分子和渗透调节等应答特征，阐明其生理学本质；发掘药效物质代谢相关基因的差异表达，解析药效物质代谢网络，探明其分子机制。以期为准确评估UV-B增强对当归生长发育、产量与品质形成的影响，阐明当归响应UV-B辐射增强的分子机制，揭示UV-B辐射增强影响当归药材品质及其机制提供科学依据。

大气平流层臭氧损耗导致地表UV-B辐射增对陆地生态系统产生直接影响。UV-B辐射增强对高海拔地区栽培当归产生胁迫及当归对有生理学和分子响应机制仍缺乏系统研究。本研究在当归道地产区开展了UV-B 辐射增强对当归形态结构、产量及品质形成的影响、当归对UV-B 辐射增强胁迫的生理及转录组响应等系统研究，取得了如下结果和关键数据：.①UV-B辐射胁迫对当归株展、归头长有显著影响，适度增加UV-B辐射能促进阿魏酸、藁本内酯、阿魏酸松柏酯、洋川芎内脂I、H、A和欧当归内脂A等合成与积累。但高剂量UV-B辐射有降低净光合速率、水分利用率、增加胞间CO2浓度、蒸腾速率和光合有效辐射的趋势。.②UV-B辐射增强胁迫条件下，不同当归品种的生理生化指标、功能基因表达及代谢通路均有差异。岷归2号（C2）光合色素（Chla、Chla+b和Chla/Chlb）均显著高于岷归1号（C1）。C2的净光合速率（Pn）、气孔导度（Gs）、光系统Ⅱ(PSⅡ)对光能的吸收效率、传递速率和光化学活性、SOD、POD和CAT高于C1，表明C2其的光合能力和抗氧化伤害能力较强，其有利于洋川芎内酯A、洋川芎内酯I、正丁基苯酞、藁本内酯和欧当归内酯A等药效物质的合成与积累。.③UV-B辐射胁迫下，C1上调差异表达基因（DEGs）、下调DEGs，特有DEGs均比C2多。表明C1抵御UV-B辐射胁迫的稳定性比C2低。C1的DEGs在核糖体、蛋白酶体富集最多，光合作用天线蛋白、淀粉和蔗糖代谢和植物氮代谢显著富集，表明C1是通过天线蛋白表达量的增加来捕获更多的光能，提高光合作用、增加碳、氮代谢所需能量，从而产生更多的中间产物、维持代谢稳定来抵御UV-B辐射胁迫。而C2在TCA循环、谷胱甘肽代谢、肌醇磷酸代谢、氰基氨基酸代谢、类黄酮生物合成、油菜素类固醇生物合成通路显著富集。预示着C2是通过广泛的初生代谢及次生代谢过程来适应UV-B辐射胁迫的。.本研究明确岷归2号比岷归1号更能适应UV-B辐射胁迫，可为高海拔、强UV-B辐射地区的当归品种区划和新品种应用提供科学依据。