School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India.
School of Bio Sciences and Technology, VIT University, Vellore 632014, Tamil Nadu, India.
J Photochem Photobiol B. 2017 Nov;176:136-144. doi: 10.1016/j.jphotobiol.2017.10.002. Epub 2017 Oct 2.
The current study was undertaken to analyse the effect of short-term UV-B and UV-C radiations in provoking carotenoid biosynthesis in Bixa orellana. Seeds of B. orellana were germinated and exposed to the short term UV pre-treatment under controlled environmental condition for 5days. The UV treated young seedlings response in pigment contents; antioxidant enzyme activity and mRNA gene expression level were analysed. The pigment content such as chlorophyll was increased in both UV-B and UV-C treated seedlings, but the total carotenoid level was decreased when compared to the control seedlings this can be attributed to the plant adaptability to survive in a stressed condition. The β-carotene level was increased in UV-B, and UV-C treated young seedlings. No significant changes have occurred in the secondary pigment such as bixin and ABA. The activity of the antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase was significantly increased in UV-B treated seedlings when compared to the UV-C treated seedlings and control. The mRNA expression of the genes involved in bixin biosynthesis pathways such as DXS, PSY, PDS, LCY-β, LCY-ε, CMT, LCD, ADH and CCD genes showed different expression pattern in UV-B and UV-C treated young seedlings. Further we analysed the gene co-expression network to identify the genes which are mainly involved in carotenoid/bixin biosynthesis pathway. Form our findings the CCD, LCY, PDS, ZDS and PSY showed a close interaction. The result of our study shows that the short term UV-B and UV-C radiations induce pigment content, antioxidant enzyme activity and different gene expression pattern allowing the plant to survive in the oxidative stress condition.
本研究旨在分析短期 UV-B 和 UV-C 辐射对胭脂树（Bixa orellana）中类胡萝卜素生物合成的影响。将胭脂树种子在受控环境条件下进行发芽，并在第 5 天进行短期 UV 预处理。分析了经 UV 处理的幼苗对色素含量、抗氧化酶活性和 mRNA 基因表达水平的反应。与对照幼苗相比，UV-B 和 UV-C 处理的幼苗中的色素含量（如叶绿素）增加，但总类胡萝卜素水平降低，这可能归因于植物适应在应激条件下生存的能力。UV-B 和 UV-C 处理的幼苗中β-胡萝卜素水平增加。次生色素如胭脂树红和 ABA 没有明显变化。与 UV-C 处理的幼苗和对照相比，UV-B 处理的幼苗中的抗氧化酶活性（如过氧化氢酶、过氧化物酶和超氧化物歧化酶）显著增加。参与胭脂树红生物合成途径的基因，如 DXS、PSY、PDS、LCY-β、LCY-ε、CMT、LCD、ADH 和 CCD 基因的 mRNA 表达在 UV-B 和 UV-C 处理的幼苗中表现出不同的表达模式。进一步，我们分析了基因共表达网络，以确定主要参与类胡萝卜素/胭脂树红生物合成途径的基因。我们的研究结果表明，短期 UV-B 和 UV-C 辐射诱导了色素含量、抗氧化酶活性和不同的基因表达模式，使植物能够在氧化应激条件下生存。
