Huang Wenjun, Lv Haiyan, Wang Ying
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of SciencesWuhan, China.
Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of SciencesGuangzhou, China.
Front Plant Sci. 2017 Jul 19;8:1274. doi: 10.3389/fpls.2017.01274. eCollection 2017.
species have been widely used both as traditional Chinese medicinal plants and ornamental perennials. Both flavonols, acting as the major bioactive components (BCs) and anthocyanins, predominantly contributing to the color diversity of flowers belong to different classes of flavonoids. It is well-acknowledged that flavonoid biosynthetic pathway is predominantly regulated by R2R3-MYB transcription factor (TF) as well as bHLH TF and WD40 protein at the transcriptional level. TFs specifically regulating anthocyanin or flavonol biosynthetic pathway have been already isolated and functionally characterized from , but a TF involved in regulating both these two pathways has not been functionally characterized to date in plants. In this study, we report the functional characterization of , a TF previously isolated from . The previous study indicated that belongs to a small subfamily of TFs containing grape and TFs, which regulate flavonoid biosynthetic pathway. The present studies show that overexpression of in tobacco leads to increased transcript levels of flavonoid pathway genes and increased contents of anthocyanins and flavonols. Yeast two-hybrid assay indicates that the C-terminal region of contributes to the autoactivation activity, and interacts with or regulator. Transient reporter assay shows that slightly activates the expression of (chalcone synthase) promoter in transiently transformed leaves of , but the addition of or regulator strongly enhances the transcriptional activation of against five promoters of the flavonoid pathway genes except (flavonol synthase). In addition, co-transformation of and in transiently transfected tobacco leaves strongly induces the expressions of flavonoid biosynthetic genes. The potential role of in modulating the biosynthesis and accumulation of sucrose-induced anthocyanin and flavonol-derived BCs is also discussed. These findings suggest that is a novel TF, which regulates the flavonoid biosynthetic pathway in , but distinctly different with the anthocyanin or flavonol-specific regulators identified previously in plants.
该物种作为传统中药材和观赏多年生植物已被广泛使用。黄酮醇作为主要生物活性成分（BCs），以及花青素，主要促成花朵的颜色多样性，它们属于不同类别的黄酮类化合物。众所周知，黄酮类生物合成途径在转录水平上主要受R2R3-MYB转录因子（TF）以及bHLH TF和WD40蛋白调控。已经从[具体植物名称未给出]中分离并对特异性调节花青素或黄酮醇生物合成途径的TF进行了功能表征，但迄今为止，尚未在[具体植物名称未给出]植物中对参与调节这两条途径的TF进行功能表征。在本研究中，我们报告了[具体基因名称未给出]的功能表征，该基因是先前从[具体植物名称未给出]中分离得到的一个TF。先前的研究表明，[具体基因名称未给出]属于包含葡萄[具体基因名称未给出]和[具体基因名称未给出]TF的[具体植物名称未给出]TF的一个小亚家族，这些TF调节黄酮类生物合成途径。目前的研究表明，在烟草中过表达[具体基因名称未给出]会导致黄酮类途径基因的转录水平增加，以及花青素和黄酮醇含量增加。酵母双杂交试验表明，[具体基因名称未给出]的C末端区域有助于自激活活性，并且[具体基因名称未给出]与[具体基因名称未给出]或[具体基因名称未给出]调节因子相互作用。瞬时报告基因试验表明，[具体基因名称未给出]在[具体植物名称未给出]瞬时转化叶片中轻微激活查尔酮合酶（CHS）启动子的表达，但添加[具体基因名称未给出]或[具体基因名称未给出]调节因子会强烈增强[具体基因名称未给出]对除黄酮醇合酶（FLS）外的黄酮类途径基因的五个启动子的转录激活。此外，在瞬时转染的烟草叶片中共转化[具体基因名称未给出]和[具体基因名称未给出]会强烈诱导黄酮类生物合成基因的表达。还讨论了[具体基因名称未给出]在调节蔗糖诱导的花青素和黄酮醇衍生的BCs生物合成和积累中的潜在作用。这些发现表明，[具体基因名称未给出]是一种新型的[具体植物名称未给出]TF，它调节[具体植物名称未给出]中的黄酮类生物合成途径，但与先前在[具体植物名称未给出]植物中鉴定的花青素或黄酮醇特异性调节因子明显不同。
