光质对小球藻(Chlorella sorokiniana)生长和代谢机制的调控

Regulation of light quality on Chlorella sorokiniana growth and metabolism

为研究光质对小球藻(Chlorella sorokiniana)生长和代谢机制的影响,分析了不同光质下C.sorokiniana的生长情况,利用Illumina平台进行转录组测序.结果表明:红､蓝光是C.sorokiniana生长的有效光质,红､蓝光培养7d后藻细胞密度分别比白光对照组的高52.96%和61.11%.C.sorokiniana在不同光质下具有独特的生理特性,蓝光组Chl a､Chl b和Car最高,分别为(17.84±0.26),(8.39±0.19),(6.04±0.08)mg/L;红光培养7d后微藻的碳水化合物和脂质含量最高,分别达到了(115.60±1.81)μg/mg和(18.64±0.54)%.通过转录组测序分析,不同光质下C.sorokiniana的基因表达存在差异,红光下碳酸酐酶､乙酰辅酶A羧化酶和脂肪酸合成酶的基因表达量较高,差异表达的基因大部分参与了脂肪酸合成和碳固定过程;蓝光下RubisCO酶的基因表达量最高且光合系统中富集的差异基因均上调表达,光合速率和碳固定速率最快;绿光下微藻大部分的基因表达量较低,新陈代谢潜能较差;白光下C.sorokiniana的TCA循环活跃,不利于储存碳水化合物和脂质.

In order to evaluate effects of light quality on the growth of Chlorella sorokiniana and metabolic mechanisms,this study was designed to monitor the growth of Chlorella sorokiniana under different light qualities with transcriptome sequencing.The results show that red and blue lights were effective for Chlorella sorokiniana growth,and the algal cell density was 52.96%and 61.11%higher than that of the white light control group after 7days of cultivation with red and blue light culture,respectively.Chlorella sorokiniana demonstrated unique physiological characteristics under different light qualities,and the blue light group had the highest concentration of Chl a,Chl b and Car with(17.84±0.26),(8.39±0.19)and(6.04±0.08)mg/L,respectively;the carbohydrate and lipid contents of the microalgae were the highest after 7 days of red light incubation,reaching(115.60±1.81)μg/mg and(18.64±0.54)%,respectively.Gene expression of Chlorella sorokiniana differed under different light qualities as indicated by transcriptome sequencing.The gene expression of carbonic anhydrase,acetyl coenzyme A carboxylase and fatty acid synthase were most significant under red light,and majority of the differentially expressed genes were involved in fatty acid synthesis and carbon fixation;the gene expression of RubisCO enzyme was the highest under blue light and the differentially expressed genes enriched in the photosynthetic system were up-regulated,and the photosynthetic rate and carbon fixation rate were the fastest;the gene expression of most of the genes in microalgae under green light was low with poor metabolic potential.The TCA cycle of Chlorella sorokiniana was active under white light,which was not conducive to the storage of carbohydrates and lipids.