State Key Laboratory of Crop Genetics and Germplasm Enhancement, Ministry of Agriculture and Rural Affairs Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Institute of Horticulture, Guizhou Academy of Agricultural Sciences, Guiyang, 55006, China.
Protoplasma. 2021 Mar;258(2):379-390. doi: 10.1007/s00709-020-01570-5. Epub 2020 Oct 28.
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.
类胡萝卜素是植物质体中发现的脂溶性色素，负责胡萝卜块根的黄色、橙色和红色。干旱是影响胡萝卜生长的主要胁迫因素之一。类胡萝卜素在高等植物的抗旱性中发挥着重要作用。在本工作中，用超高效液相色谱（UPLC）测定了经 15%聚乙二醇（PEG）6000 处理后 3 种不同颜色的胡萝卜品种‘黑田五寸人参’（橙色）、‘本红金时’（红色）和‘七头黄’（黄色）的类胡萝卜素含量，然后用实时荧光定量 PCR（RT-qPCR）测定类胡萝卜素合成和降解相关基因的表达水平。发现干旱胁迫下‘七头黄’块根中β-胡萝卜素含量的增加与 DcPSY2 和 DcLCYB 的表达水平有关。PEG 处理下‘七头黄’和‘黑田五寸人参’中叶黄素的增加和α-胡萝卜素含量的降低可能与 DcCYP97A3、DcCHXE 和 DcCHXB1 的表达水平有关。3 个品种中 DcNCED1 和 DcNCED2 的表达水平显著增加，表明 NCED 基因可能对干旱胁迫有响应。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‘黑田五寸人参’比其他品种更能适应干旱胁迫，β-胡萝卜素和叶黄素可能参与了胡萝卜的胁迫抗性过程。
