UV-B promotes flavonoid synthesis in Ginkgo biloba leaves
UV-B promotes flavonoid synthesis in Ginkgo biloba leaves
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DOI：
10.1016/j.indcrop.2020.112483
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发表时间：
2020-09-01
影响因子：
5.9
通讯作者：
Jin, Biao
中科院分区：
文献类型：
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作者：
Zhao, Beibei;Wang, Li;Jin, Biao
紫外线b （UV-B）辐射是植物环境胁迫的天然来源。值得注意的是，植物已经进化出各种保护机制来对抗UV-B暴露的有害影响，包括产生吸收uv的类黄酮化合物。黄酮类化合物是银杏提取物中的药用活性物质。为了阐明百叶黄酮耐受UV-B的分子机制，我们测定了长期暴露于UV-B后百叶黄酮醇的组成和转录组学特征。通过高效液相色谱和质谱分析，我们观察到UV-B照射后叶中黄酮醇的积累。特别是异鼠李素增加了16倍以上。结合转录组数据和实时定量聚合酶链反应，发现UV-B暴露后，与类黄酮合成相关的结构基因表达上调。其中FLS （Gb_22751）和f3’h （Gb_19792、Gb_04545和Gb_11520）的表达量显著增加，表明它们在长时间UV-B辐射下类黄酮合成响应中发挥重要作用。此外，我们发现bZIP转录因子（TF） Gb_12012（编码细长下胚轴-5、HY5）和MYB转录因子（Gb_38090）表达上调，而MYB转录因子（Gb_18153、Gb_40629和Gb_05115）表达下调。我们进一步鉴定了两个UV-B信号分子，包括UVR8 （Gb_14008）和组成型光形态形成-1 （COP1, Gb_15627）。上述结果表明，长期增强的UV-B辐射可促进黄酮类化合物的生物合成和代谢，有利于药用活性成分的积累。
Ultraviolet-B (UV-B) radiation is a natural source of environmental stress for plants. Notably, plants have evolved various protective mechanisms to combat the detrimental effects of UV-B exposure, including the production of UV-absorbing flavonoid compounds. Flavonoids are pharmaceutical active substances in Ginkgo biloba extracts. To clarify the molecular mechanisms underlying UV-B tolerance in G. biloba, we determined the flavonol composition and transcriptomic profile of G. biloba leaves after long-term UV-B exposure. Using high performance liquid chromatography and mass spectroscopy, we observed significant accumulation of flavonols in G. biloba leaves after UV-B exposure. In particular, isorhamnetin increased more than 16-fold. Combined transcriptome data with quantitative real-time polymerase chain reaction, structural genes involved in flavonoid synthesis were identified to be up-regulated expression after UV-B exposure. Particularly, the expression of FLS (Gb_22751) and F3'H (Gb_19792, Gb_04545, and Gb_11520) increased significantly, indicating their important roles in flavonoid synthesis response to long-term UV-B radiation. In addition, we found bZIP transcription factor (TF) Gb_12012 (encoding elongated hypocotyl-5, HY5) and MYB TFs (Gb_38090) were up-regulated, while MYB TFs (Gb_18153, Gb_40629, and Gb_05115) were down-regulated. We further identified two UV-B signalling molecules, including UVR8 (Gb_14008) and constitutive photomorphogenic-1 (COP1, Gb_15627) in G. biloba. These results suggest that the enhanced long-term UV-B radiation could promote flavonoid biosynthesis and metabolism, which is beneficial for the accumulation of medically active ingredients in G. biloba leaves.