Dept. of Agronomy & Plant Breeding, Faculty of Agricultural Sciences, University of Guilan, P.O. Box: 41635-1314, Rasht, Iran.
Dept. of Plant Biotechnology, Faculty of Agricultural Sciences, University of Guilan, P.O Box: 41635-1314, Rasht, Iran.
J Plant Physiol. 2018 Nov;230:101-108. doi: 10.1016/j.jplph.2018.10.014. Epub 2018 Oct 17.
Thymus vulgaris L. (Lamiaceae), a well-known aromatic medicinal herb, has many important essential constituents in its oil, including γ-terpinene, carvacrol, thymol, and p-cymene. Gibberellins comprise hundreds of components, which regulate several various growths and underlying developmental processes, such as cell division and elongation, shoot elongation, seed germination, and gene expression. In this study, we investigated the influence of sprayed gibberellic acid (GA) treatments on the internode length, leaf morphology, length of new shoot, expression of monoterpene synthase genes and monoterpenes content during two plant growth stages. Our results showed that increasing of internode length was a clear effect of GA that was varied with internode position. The results also showed that all internodes displayed a dramatic increase in the highest concentration of GA. Also, the foliar application of GA resulted in not only an increased expression level of monoterpene synthase genes, but also the improved production of a monoterpene, especially in the moderate concentration of GA that they were up-regulated. In the lowest GA concentrations, relative expression levels were similar or lower than the control plants and a notable downregulation in those genes was observed in the application of the highest concentration of GA rather than the moderate concentrations. Overall, the expression of two out of five monoterpene synthase genes, TPS and CYP71D181, showed a correlation with the level of γ-terpinene and carvacrol, respectively, indicating that they are regulated at the transcriptional levels.
普通百里香（唇形科）是一种广为人知的芳香药用草本植物，其精油中含有许多重要的基本成分，包括γ-松油烯、香芹酚、百里酚和对伞花烃。赤霉素由数百种成分组成，调节多种不同的生长和潜在的发育过程，如细胞分裂和伸长、芽伸长、种子萌发和基因表达。在这项研究中，我们研究了喷施赤霉素（GA）处理对两个生长阶段的节间长度、叶片形态、新梢长度、单萜合酶基因表达和单萜含量的影响。我们的结果表明，GA 处理导致节间长度增加，且变化与节间位置有关。结果还表明，所有节间在 GA 最高浓度下均表现出显著的增长。此外，GA 的叶面喷施不仅导致单萜合酶基因的表达水平增加，而且还改善了单萜的产生，特别是在中等浓度的 GA 下，它们被上调。在 GA 的最低浓度下，相对表达水平与对照植物相似或更低，而在应用最高浓度的 GA 时，这些基因的表达明显下调，而不是在中等浓度下。总的来说，五个单萜合酶基因中的两个，TPS 和 CYP71D181，其表达与γ-松油烯和香芹酚的水平分别相关，表明它们在转录水平上受到调控。
