WRKY transcription factors, one of the largest transcription factor families, play important roles in regulating the synthesis of secondary metabolites. In sweet osmanthus (Osmanthus fragrans), the monoterpenes have been demonstrated as the most important volatile compounds, and the W-box, which is the cognate binding site of WRKY transcription factors, could be identified in most of the terpene-synthesis-related genes' promoters. However, the role of the WRKY family in terpene synthesis in sweet osmanthus has rarely been examined. In this study, 154 WRKY genes with conserved WRKY domain were identified and classified into three groups. The group II was further divided into five subgroups, and almost all members of IId contained a plant zinc cluster domain. Eight OfWRKYs (OfWRKY7/19/36/38/42/84/95/139) were screened from 20 OfWRKYs for their flower-specific expression patterns in different tissues. Simultaneously, the expression patterns of OfWRKYs and emission patterns of volatile compounds during the flowering process were determined and gas chromatography-mass spectrometry results showed that monoterpenes, such as linalool and ocimene, accounted for the highest proportion, contributing to the floral scent of sweet osmanthus in two cultivars. In addition, correlation analysis revealed the expression patterns of OfWRKYs (OfWRKY7/19/36/139) were each correlated with distinct monoterpenes (linalool, linalool derivatives, ocimene and ocimene derivatives). Subcellular localization analysis showed that p35S::GFP-OfWRKY7/38/95/139 were localized in the nucleus and OfWRKY139 had very strong transactivation activity. Collectively, the results indicated potential roles of OfWRKY139 and OfWRKYs with plant zinc cluster domain in regulating synthesis of aromatic compounds in sweet osmanthus, laying the foundation for use of OfWRKYs to improve the aroma of ornamental plants.

中文翻译：

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全基因组研究甜桂花中WRKY转录因子及其对香气合成的潜在调控。

WRKY转录因子是最大的转录因子家族之一，在调节次级代谢产物的合成中起重要作用。在甜桂花（Osmanthus fragrans）中，单萜已被证明是最重要的挥发性化合物，W-box（WRKY转录因子的同源结合位点）可在大多数与萜烯合成相关的基因中找到的发起人。但是，很少研究WRKY家族在甜桂花中萜烯合成中的作用。在这项研究中，鉴定了具有保守WRKY结构域的154个WRKY基因，并将其分为三类。II组进一步分为五个亚组，IId的几乎所有成员都包含植物锌簇域。从20个OfWRKY中筛选了八个OfWRKY（OfWRKY7 / 19/36/38/42/84/95/139），以了解它们在不同组织中的花特异性表达模式。同时，测定了开花过程中OfWRKYs的表达模式和挥发性化合物的排放模式，气相色谱-质谱分析结果表明，芳樟和西子等萜烯含量最高，有助于桂花的花香。在两个品种中。此外，相关分析显示，OfWRKYs（OfWRKY7 / 19/36/139）的表达模式分别与不同的单萜（芳樟醇，芳樟醇衍生物，罗勒烯和罗勒烯衍生物）相关。亚细胞定位分析表明p35S :: GFP-OfWRKY7 / 38/95/139位于细胞核中，OfWRKY139具有非常强的反式激活活性。总体而言，结果表明具有植物锌簇结构域的OfWRKY139和OfWRKYs在调节桂花香气化合物合成中的潜在作用，为使用OfWRKYs改善观赏植物的香气奠定了基础。