温度对真眼点藻生长、总脂及二十碳五烯酸(EPA)合成的影响

Effects of Temperature on the Growth,Total Lipid and Eicosapentaenoic Acid Synthesis of Eustigmatos sp.

真眼点藻可以积累二十碳五烯酸(EPA)而受到广泛关注,温度是影响多不饱和脂肪酸合成的重要因素。本研究以真眼点藻(Eustigmatos sp.JHsu-01)为材料,设置高温组(30℃)和低温组(15℃)两种培养条件,通过测定生长、脂类积累、脂肪酸组成和甘油酯合成关键基因表达量的变化,探究温度对EPA合成规律的影响。结果表明,低温培养促进了真眼点藻JHsu-01膜脂和EPA的合成,EPA含量最高达到2.78%DW,糖脂是EPA的主要载体,但温度可以改变EPA在糖脂和中性脂之间的分配比例。转录组结果显示,低温条件下,脂肪酸从头合成、三酰甘油(GPAT、plsC、PLPP和DGAT)、糖脂(MGD和DGD)、硫脂(SQD1和SQD2)和ω-3合成途径(Δ5 Des、Δ6 Des和Δ15 Des)中多个关键酶基因表达上调。综上所述,低温可以促进真眼点藻EPA的合成,同时也是一种获得高含量糖脂型EPA的理想培养方式,研究结果为提高真眼点藻EPA产量提供理论和技术依据。

Eustigmatos sp.has received great attention due to its high content of eicosapentaenoic acid(EPA).Temperature is an important factor affecting the synthesis of polyunsaturated fatty acids.In this study,Eustigmatos sp.JHsu-01 was used as the experimental strain and cultured in the 2 conditions,high temperature(30℃)and low temperature(15℃).The growth,lipid accumulation,fatty acid composition and the expressions of key genes involved in lipid synthesis were measured and the effects of temperature on the EPA synthesis patterns were investigated.The results showed that the low-temperature enhanced the synthesis of membrane lipids and EPA in Eustigmatos sp.,and the highest EPA content was 2.78%DW.Glycolipids were the main carrier of EPA,but temperature changed the distribution of EPA between glycolipids and neutral lipids.The results of transcriptome demonstrated that under low temperature conditions,the expression of key genes in de novo fatty acid synthesis,triacylglycerols(GPAT,plsC,PLPP and DGAT),glycolipids(MGD and DGD),sulfolipids(SQD1 and SQD2)andω-3 synthesis pathways(Δ5 Des,Δ6 Des andΔ15 Des)were up-regulated.In conclusion,low temperature is an important culture condition to promote the synthesis of EPA in Eustigmatos,and it is also an optimal cultivation approach for obtaining high-content glycolipid EPA.The research results may provide a theoretical and technical guidance to increase the production of EPA.