Li Wei-xing, Yang Shun-bo, Lu Zhaogeng, He Zhi-chong, Ye Yun-ling, Zhao Bei-bei, Wang Li, Jin Biao
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.
College of Resource and Environment, Xizang Agriculture and Animal Husbandry College, Tibet, 860000 China
Hortic Res. 2018 Mar 1;5:12. doi: 10.1038/s41438-018-0015-4. eCollection 2018.
is grown worldwide as an ornamental plant for its golden leaf color. However, the regulatory mechanism of leaf coloration in remains unclear. Here, we compared gold-colored mutant leaves and normal green leaves in cytological, physiological and transcriptomic terms. We found that chloroplasts of the mutant were fewer and smaller, and exhibited ruptured thylakoid membranes, indistinct stromal lamellae and irregularly arranged vesicles. Physiological experiments also showed that the mutant had a lower chlorophyll, lower flavonoid and higher carotenoid contents (especially lutein). We further used transcriptomic sequencing to identify 116 differentially expressed genes (DEGs) and 46 transcription factors (TFs) involved in chloroplast development, chlorophyll metabolism, pigment biosynthesis and photosynthesis. Among these, the chlorophyll biosynthesis-related showed down-regulation, while chlorophyll degradation-related had up-regulated expression in mutant leaves. , , and , which are involved in carotenoid biosynthesis were up-regulated. Quantitative real-time PCR (RT-qPCR) further confirmed the altered expression levels of these genes at three stages. The alteration of and / gene expression might affect chlorophyll biosynthesis and promote degradation of chlorophyll to chlorophyll , while the up-regulated genes , and enhanced carotenoid accumulation. Consequently, changes in the ratio of carotenoids to chlorophylls were the main factors driving the golden leaf coloration in the mutant .
作为一种因其金色叶片颜色而在全球种植的观赏植物。然而，其叶片着色的调控机制仍不清楚。在此，我们从细胞学、生理学和转录组学方面比较了金色突变体叶片和正常绿色叶片。我们发现突变体的叶绿体数量更少且更小，类囊体膜破裂，基质片层不清晰，囊泡排列不规则。生理实验还表明，突变体的叶绿素含量较低，类黄酮含量较低，类胡萝卜素含量较高（尤其是叶黄素）。我们进一步利用转录组测序鉴定了116个差异表达基因（DEGs）和46个参与叶绿体发育、叶绿素代谢、色素生物合成和光合作用的转录因子（TFs）。其中，与叶绿素生物合成相关的基因表现出下调，而与叶绿素降解相关的基因在突变体叶片中表达上调。参与类胡萝卜素生物合成的基因、和上调。定量实时PCR（RT-qPCR）进一步证实了这些基因在三个阶段表达水平的变化。和/基因表达的改变可能影响叶绿素生物合成并促进叶绿素向叶绿素的降解，而上调的基因、和增强了类胡萝卜素的积累。因此，类胡萝卜素与叶绿素比例的变化是驱动突变体叶片呈现金色的主要因素。
