Carotenoids are liposoluble pigments found in plant chromoplasts that are responsible for the yellow, orange, and red colors of carrot taproots. Drought is one of the main stress factors affecting carrot growth. Carotenoids play important roles in drought resistance in higher plants. In the present work, the carotenoid contents in three different-colored carrot cultivars, 'Kurodagosun' (orange), 'Benhongjinshi' (red), and 'Qitouhuang' (yellow), were determined by ultra-high-performance liquid chromatography (UPLC) after 15% polyethylene glycol (PEG) 6000 treatment. Real-time fluorescence quantitative PCR (RT-qPCR) was then used to determine the expression levels of carotenoid synthesis- and degradation-related genes. Increases in β-carotene content in 'Qitouhuang' taproots under drought stress were found to be related to the expression levels of DcPSY2 and DcLCYB. Increases in lutein and decreases in α-carotene content in 'Qitouhuang' and 'Kurodagosun' under PEG treatment may be related to the expression levels of DcCYP97A3, DcCHXE, and DcCHXB1. The expression levels of DcNCED1 and DcNCED2 in the three cultivars significantly increased, thus suggesting that NCED genes could respond to drought stress. Analysis of the growth status and carotenoid contents of carrots under PEG treatment indicated that the orange cultivar 'Kurodagosun' has better adaptability to drought stress than the other cultivars and that β-carotene and lutein may be involved in the stress resistance process of carrot.

中文翻译：

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模拟干旱胁迫对胡萝卜主根类胡萝卜素含量及相关基因表达的影响

类胡萝卜素是在植物有色体中发现的脂溶性色素，负责胡萝卜主根的黄色、橙色和红色。干旱是影响胡萝卜生长的主要压力因素之一。类胡萝卜素在高等植物的抗旱性中起重要作用。在目前的工作中，通过超高效液相色谱法（UPLC）测定了三种不同颜色的胡萝卜品种“黑田孙”（橙色）、“本红金石”（红色）和“七头黄”（黄色）中的类胡萝卜素含量。 ) 15% 聚乙二醇 (PEG) 6000 处理后。然后使用实时荧光定量 PCR (RT-qPCR) 来确定类胡萝卜素合成和降解相关基因的表达水平。“七头黄”β-胡萝卜素含量增加 发现干旱胁迫下的主根与 DcPSY2 和 DcLCYB 的表达水平有关。PEG处理下'七头黄'和'黑田松'中叶黄素的增加和α-胡萝卜素含量的减少可能与DcCYP97A3、DcCHXE和DcCHXB1的表达水平有关。三个品种中DcNCED1和DcNCED2的表达水平显着升高，表明NCED基因可以响应干旱胁迫。PEG处理下胡萝卜的生长状况和类胡萝卜素含量分析表明，橙色品种'Kurodagosun'比其他品种具有更好的干旱胁迫适应性，β-胡萝卜素和叶黄素可能参与了胡萝卜的抗逆过程。PEG处理下'七头黄'和'黑田松'中叶黄素的增加和α-胡萝卜素含量的减少可能与DcCYP97A3、DcCHXE和DcCHXB1的表达水平有关。DcNCED1 和 DcNCED2 在三个品种中的表达水平显着增加，表明 NCED 基因可以响应干旱胁迫。PEG处理下胡萝卜的生长状况和类胡萝卜素含量分析表明，橙色品种'Kurodagosun'比其他品种具有更好的干旱胁迫适应性，β-胡萝卜素和叶黄素可能参与了胡萝卜的抗逆过程。PEG处理下'七头黄'和'黑田松'中叶黄素的增加和α-胡萝卜素含量的减少可能与DcCYP97A3、DcCHXE和DcCHXB1的表达水平有关。DcNCED1 和 DcNCED2 在三个品种中的表达水平显着增加，表明 NCED 基因可以响应干旱胁迫。PEG处理下胡萝卜的生长状况和类胡萝卜素含量分析表明，橙色品种'Kurodagosun'比其他品种具有更好的干旱胁迫适应性，β-胡萝卜素和叶黄素可能参与了胡萝卜的抗逆过程。DcNCED1 和 DcNCED2 在三个品种中的表达水平显着增加，表明 NCED 基因可以响应干旱胁迫。PEG处理下胡萝卜的生长状况和类胡萝卜素含量分析表明，橙色品种'Kurodagosun'比其他品种具有更好的干旱胁迫适应性，β-胡萝卜素和叶黄素可能参与了胡萝卜的抗逆过程。三个品种中DcNCED1和DcNCED2的表达水平显着升高，表明NCED基因可以响应干旱胁迫。PEG处理下胡萝卜的生长状况和类胡萝卜素含量分析表明，橙色品种'Kurodagosun'比其他品种具有更好的干旱胁迫适应性，β-胡萝卜素和叶黄素可能参与了胡萝卜的抗逆过程。