外源的微藻DGAT基因表达对酿酒酵母生长和脂质的影响  

Effects of expressing exogenous microalgal DGAT genes on the growth and lipids of Saccharomyces cerevisiae

作　　者：胡澄溪 刘伟[1] 毕燕会[1] 周志刚[2] HU Chengxi;LIU Wei;BI Yanhui;ZHOU Zhigang(Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources,Ministry of Education,Shanghai Ocean University,Shanghai 201306,China;International Research Center for Marine Biosciences,Ministry of Science and Technology,Shanghai Ocean University,Shanghai 201306,China)

机构地区：[1]上海海洋大学,水产遗传资源开发利用教育部重点实验室,上海201306 [2]上海海洋大学,国家海洋生物科学国际联合研究中心,上海201306

出　　处：《水产学报》2025年第5期41-49,共9页Journal of Fisheries of China

基　　金：国家自然科学基金(31772821);国家“双一流”水产学科~~。

摘　　要：【目的】三酰甘油(TAG)合成缺陷型酿酒酵母突变株H1246常用于其他生物二酰基甘油酰基转移酶(DGAT)的基因功能鉴定。为了解外源DGAT的基因表达对酵母细胞脂质及生长的影响。【方法】将缺刻缘绿藻1个Ⅰ型和3个Ⅱ型的DGAT分别转化H1246菌株,经筛选获得tDGAT1、tDGAT2A、tDGAT2B及tDGAT2C等4株转目的基因酵母。通过显微观察、分光光度法、重量法、棒状色谱分析、气相色谱-质谱分析对酿酒酵母的形态和脂滴、细胞密度、单位体积生物量、生物质生产率、总脂、总脂肪酸、TAG含量进行检测。【结果】稳定生长期时的显微观察结果显示,这4个外源基因均能使H1246菌株恢复TAG的合成和贮存能力,进而在细胞中出现油滴。油脂分析结果表明,tDGAT1菌株的TAG及脂肪酸含量最高,且显著高于野生型Scy62及其他3株转目的基因菌株的水平。生长性能数据显示,4个外源基因均能使H1246菌株的细胞密度达到Scy62的水平,这可能是由于TAG的合成消耗了游离脂肪酸,以减轻其对细胞产生的伤害所致。但tDGAT1菌株的生长迟滞期明显延长,以致其生长速率最低。【结论】将缺刻缘绿藻不同类型的外源DGAT转化酿酒酵母后,使后者的生长性能及脂质含量产生不同的变化。该结果为利用基因工程改造酵母菌株以生产人类所需要的目的油脂研究奠定了基础。The H1246 mutant of Saccharomyces cerevisiae,which is deficient in triacylglycerol(TAG)synthesis,is commonly used to elucidate the functions of exogenous genes encoding diacylglycerol acyltransferase(DGAT).To investigate the effects of exogenous DGATs on lipid synthesis and yeast cell growth,one typeⅠ(DGAT1)and three typeⅡDGAT(DGAT2a,DGAT2b,DGAT2c)genes of Myrmecia incisa were individually transformed into the H1246 strain,yielding four transgenic yeast strains.The morphology,lipid droplet formation,cell density,volumetric biomass,biomass productivity,total lipids,total fatty acids,and TAG content of S.cerevisiae were analyzed using microscopic observation,spectrophotometry,gravimetry,Rod thin-layer chromatography,and gas chromatography-mass spectrometry.Microscopic observation during the stable growth phase revealed oil droplets in all four transgenic strains,indicating that the exogenous genes promoted TAG synthesis and storage.Lipid component analysis showed that the tDGAT1 strain exhibited the highest TAG and fatty acid content among all the transgenic strains and the wild-type Scy62.Growth performance analysis revealed that cell densities of strains transformed with the exogenous genes reached the levels comparable to Scy62 yeast,likely due to the consumption of free fatty acids during TAG synthesis,thereby reducing cellular damage.However,the tDGAT1 strain exhibited the lowest growth,attributed to a significantly prolonged period of growth retardation.Differences in growth performance and lipid components among the transgenic strains may be due to unique domains with the DGATs.This study provides a foundation for producing desired lipids using genetically engineered yeast strains.

关 键 词：酿酒酵母 缺刻缘绿藻 二酰基甘油酰基转移酶(DGAT) 三酰甘油(TAG) 生长 

分 类 号：S917.1[农业科学—水产科学]