Henan Provincial Key Laboratory of Plant-Microbe Interactions, Shangqiu Normal University, Shangqiu, Henan, 476000, China.
Henan Provincial Key Laboratory of Plant-Microbe Interactions, Shangqiu Normal University, Shangqiu, Henan, 476000, China.
J Plant Physiol. 2023 May;284:153962. doi: 10.1016/j.jplph.2023.153962. Epub 2023 Mar 16.
The β-carotene hydroxylase gene (BCH) regulates zeaxanthin production in response to high light levels ro protect Chrysanthemum morifolium plants against light-induced damage. In this study, the Chrysanthemum morifolium CmBCH1 and CmBCH2 genes were cloned and their functional importance was assessed by overexpressing them in Arabidopsis thaliana. These transgenic plants were evaluated for gene-related changes in phenotypic characteristics, photosynthetic activity, fluorescence properties, carotenoid biosynthesis, aboveground/belowground biomass, pigment content, and the expression of light-regulated genes under conditions of high light stress relative to wild-type (WT) plants. When exposed to high light stress, WT A. thaliana leaves turned yellow and the overall biomass was reduced compared to that of the transgenic plants. WT plants exposed to high light stress also exhibited significant reductions in the net photosynthetic rate, stomatal conductance, Fv/Fm, qP, and ETR, whereas these changes were not observed in the transgenic CmBCH1 and CmBCH2 plants. Lutein and zaxanthin levels were significantly increased in the transgenic CmBCH1 and CmBCH2 lines, with progressive induction with prolonged light exposure, whereas no significant changes were observed in light-exposed WT plants. The transgenic plants also expressed higher levels of most carotenoid biosynthesis pathway genes, including phytoene synthase (AtPSY), phytoene desaturase (AtPDS), lycopene-β-cyclase (AtLYCB), and ζ-carotene desaturase (AtZDS). The elongated hypocotyl 5 (HY5) and succinate dehydrogenase (SDH) genes were significantly induced following exposure to high light conditions for 12h, whereas phytochrome-interacting factor 7 (PIF7) was significantly downregulated in these plants.
β-胡萝卜素羟化酶基因（BCH）通过响应高光水平来调节玉米黄质的产生，以保护菊花植物免受光诱导的损伤。在这项研究中，克隆了菊花的 CmBCH1 和 CmBCH2 基因，并通过在拟南芥中过表达它们来评估它们的功能重要性。与野生型（WT）植物相比，这些转基因植物在高光胁迫条件下，对与基因相关的表型特征、光合作用活性、荧光特性、类胡萝卜素生物合成、地上/地下生物量、色素含量以及光调节基因的表达进行了评估。当暴露于高光胁迫时，WT 拟南芥叶片变黄，整体生物量减少，而与转基因植物相比。WT 植物在高光胁迫下的净光合速率、气孔导度、Fv/Fm、qP 和 ETR 也显著降低，而这些变化在转基因 CmBCH1 和 CmBCH2 植物中未观察到。在转基因 CmBCH1 和 CmBCH2 系中，叶黄素和玉米黄质的水平显著增加，随着光照时间的延长，呈渐进诱导，而在光照的 WT 植物中没有观察到显著变化。转基因植物还表达了更高水平的大多数类胡萝卜素生物合成途径基因，包括八氢番茄红素合酶（AtPSY）、八氢番茄红素去饱和酶（AtPDS）、番茄红素-β-环化酶（AtLYCB）和 ζ-胡萝卜素去饱和酶（AtZDS）。在暴露于高光条件 12 小时后，伸长的下胚轴 5（HY5）和琥珀酸脱氢酶（SDH）基因显著诱导，而这些植物中的光敏色素相互作用因子 7（PIF7）显著下调。
