Aslam Muhammad Zeshan, Lin Xiang, Li Xiang, Yang Nan, Chen Longqing
Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China.
Southwest Research Centre for Engineering Technology of Landscape Architecture (State Forestry and Grassland Administration), Southwest Forestry University, Kunming 650224, China.
Plants (Basel). 2020 Jun 23;9(6):785. doi: 10.3390/plants9060785.
Wintersweet ( L.) is an ornamental and economically significant shrub known for its unique flowering characteristics, especially the emission of abundant floral volatile organic compounds. Thus, an understanding of the molecular mechanism of the production of these compounds is necessary to create new breeds with high volatile production. In this study, two transcription factors ( and ) of Wintersweet H29 were functionally characterized to illustrate their possible role in the production of volatile compounds. The qRT-PCR results showed that the expression of and increased from the flower budding to full bloom stage, indicating that these two genes may play an essential role in blooming and aroma production in wintersweet. Gas chromatography-mass spectroscopy (GC-MS) analysis revealed that the overexpression of in arabidopsis () mutant (Salk_083483) and tobacco () genotype Petit Havana SR1 significantly increased floral volatile monoterpene, especially linalool, while the overexpression of in ecotype Columbia-0 (Col-0) and tobacco genotype SR1 increased floral sesquiterpene β-caryophyllene production in both types of transgenic plants respectively. High expression of terpene synthase (TPS) genes in transgenic along with high expression of and in transgenic plants was also observed. The application of a combination of methyl jasmonic acid (MeJA) and gibberellic acid (GA3) showed an increment in linalool production in -overexpressing arabidopsis plants, and the high transcript level of TPS genes also suggested the involvement of in the jasmonic acid (JA) signaling pathway. These results indicate that both the transcription factors of wintersweet are possibly involved in the positive regulation and biosynthesis of monoterpene (linalool) and sesquiterpene (β-caryophyllene) in transgenic plants. This study also indicates the potential application of wintersweet as a valuable genomic material for the genetic modification of floral scent in other flowering plants that produce less volatile compounds.
腊梅（Chimonanthus praecox (L.) Link）是一种具有观赏价值且经济意义重大的灌木，以其独特的开花特性而闻名，尤其是能释放大量的花香挥发性有机化合物。因此，了解这些化合物产生的分子机制对于培育具有高挥发性的新品种至关重要。在本研究中，对腊梅H29的两个转录因子（ 和 ）进行了功能表征，以阐明它们在挥发性化合物产生中可能发挥的作用。qRT-PCR结果表明， 和 的表达从花芽分化期到盛花期逐渐增加，这表明这两个基因可能在腊梅的开花和香气产生中起重要作用。气相色谱-质谱联用（GC-MS）分析显示，在拟南芥（Arabidopsis thaliana）突变体（Salk_083483）和烟草（Nicotiana tabacum）基因型Petit Havana SR1中过表达 显著增加了花香挥发性单萜，尤其是芳樟醇，而在拟南芥生态型Columbia-0（Col-0）和烟草基因型SR1中过表达 分别增加了两种转基因植物中花香倍半萜β-石竹烯的产量。在转基因拟南芥中还观察到萜类合酶（TPS）基因的高表达以及转基因植物中 和 的高表达。茉莉酸甲酯（MeJA）和赤霉素（GA3）组合处理显示，在过表达 的拟南芥植株中芳樟醇产量增加，TPS基因的高转录水平也表明 参与了茉莉酸（JA）信号通路。这些结果表明，腊梅的这两个转录因子可能参与了转基因植物中单萜（芳樟醇）和倍半萜（β-石竹烯）的正向调控和生物合成。本研究还表明，腊梅作为一种有价值的基因组材料，在对挥发性化合物产生较少的其他开花植物进行花香遗传改良方面具有潜在应用价值。
