School of Science and Technology, Örebro Life Science Centre, Örebro University, Örebro, SE-70182, Sweden.
Department of Horticulture, The State Agricultural Ministry Key Laboratory of Horticultural Plant Growth, Development & Quality Improvement, Zhejiang University, Hangzhou, Zhejiang Province, 310058, China.
Photochem Photobiol Sci. 2019 Feb 13;18(2):424-433. doi: 10.1039/c8pp00480c.
Expression of cucumber (Cucumis sativus) genes encoding the phenylpropanoid and flavonoid biosynthetic enzymes phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and chalcone synthase (CHS), was studied under control light conditions (photosynthetically active radiation, PAR) in root, stem, and leaf. Furthermore, the expression was quantified in leaves illuminated with PAR and supplemental ultraviolet-A (315-400 nm) or ultraviolet-B (280-315 nm) radiation. The expression patterns of all twelve CsPAL, three CsC4H, and three CsCHS genes were established. Among the genes regulated by UV two general expression patterns emerge. One pattern applies to genes primarily regulated by enriched UV-A illumination (pattern 1). Another pattern (pattern 2) was found for the genes regulated by enriched UV-B. Three of the pattern 2 genes (CsPAL4, CsPAL10, and CsCHS2) displayed a particular sub-pattern (pattern 2b) with transcription enriched by at least 30-fold. In contrast to the other genes studied, the promoters of the genes regulated according to pattern 2b contained a combination of a number of cis-acting regulatory elements (MREs, ACEs, and G-boxes) that may be of importance for the particularly high enhancement of expression under UV-B-containing light. The regulation of phenylpropanoid and flavonoid biosynthesis genes in cucumber resembles that of a number of other plants. However, cucumber, due to its greater size, is an attractive species for combining more detailed studies of the morphology, physiological parameters and fine regulation of spatial and temporal expression of key genes. This, in turn, can facilitate the quantitative investigation of the relationships among different promoter motifs, the expression levels of each of these three genes, and metabolite accumulation profiles.
黄瓜（Cucumis sativus）基因表达的研究，这些基因编码苯丙烷和类黄酮生物合成酶苯丙氨酸解氨酶（PAL）、肉桂酸 4-羟化酶（C4H）和查尔酮合酶（CHS），在根、茎和叶的对照光条件（光合有效辐射，PAR）下进行。此外，还在叶片中定量分析了在 PAR 和补充的紫外-A（315-400nm）或紫外-B（280-315nm）辐射下的表达情况。建立了所有 12 个 CsPAL、3 个 CsC4H 和 3 个 CsCHS 基因的表达模式。在受 UV 调节的基因中，出现了两种通用的表达模式。一种模式适用于主要受富含 UV-A 照射调节的基因（模式 1）。另一种模式（模式 2）适用于受富含 UV-B 调节的基因。模式 2 中的 3 个基因（CsPAL4、CsPAL10 和 CsCHS2）表现出一种特殊的亚模式（模式 2b），转录增强至少 30 倍。与研究的其他基因不同，根据模式 2b 调节的基因的启动子包含一系列顺式作用调节元件（MREs、ACEs 和 G-框），这些元件可能对在含有 UV-B 的光下表达的特别高增强具有重要意义。黄瓜中苯丙烷和类黄酮生物合成基因的调控类似于许多其他植物。然而，由于黄瓜体积较大，因此它是一种很有吸引力的物种，可以结合更详细地研究关键基因的形态、生理参数以及时空表达的精细调控。反过来，这可以促进不同启动子基序、这三个基因的每个基因的表达水平以及代谢物积累谱之间的关系的定量研究。
