摘要
为提高异养条件下索罗金小球藻(Chlorella sorokiniana)蛋白质含量,扩大该藻株在食品和饲料领域的应用,研究发现当异养条件下培养的C. sorokiniana GT-1细胞转入光自养培养条件后,蛋白质含量显著提高。通过转录组学分析揭示了C. sorokiniana GT-1在异养转自养过程中基因表达发生全局变化,其中糖酵解途径与磷酸戊糖途径上调,氮转运和同化途径中的关键酶的编码基因明显上调,且谷氨酸族氨基酸和丙酮酸族氨基酸的生物合成途径的多个酶在转录水平上显著增强。研究还发现在异养条件下藻细胞仍然可以表达部分光合作用蛋白的编码基因,当转入光自养条件后24h内绝大多数光合作用相关蛋白编码基因的转录被激活。结果表明在异养转自养条件过程中蛋白质含量的升高与氮的吸收及利用增加、还原能合成的增强、部分氨基酸的合成上调及光合作用蛋白质的大量合成有关。研究为后续如何通过培养条件优化或代谢工程改造提高C. sorokiniana GT-1产蛋白质的能力提出了新的思路。
Chlorella sorokiniana(Chlorophyta)is a ubiquitous,fast-growing green alga that can grow under heterotrophic conditions to produce biomass and lipids.However,the low protein content of C.sorokiniana cells grown under heterotrophic conditions limits their commercial applications.This study revealed that the protein contents of the C.sorokiniana GT-1 cells increased significantly when these cells were transferred to the photoautotrophic from the heterotrophic conditions.Transcriptomics analysis showed that the glycolysis and pentose phosphate pathways were significantly upregulated and those genes encoding key enzymes involved in the nitrogen transport and assimilation were significantly induced.As for the biosynthesis of amino acids(aa),only those involved in the glutamic and pyruvate families were upregulated.In addition,many genes encoding photosynthetic proteins were expressed under heterotrophic conditions,and most of them were up-regulated during 24 hours after transiting from heterotrophic conditions to photoautotrophic conditions.These results indicated that the enhanced protein content of C.sorokiniana GT-1 cells transiting from the heterotrophic to photoautotrophic conditions may be attributable to the elevated absorption and utilization of nitrate,production of reducing equivalents,biosynthesis of some amino acids,and regeneration of photosynthetic proteins.This study provides new insights into enhancing the protein production of C.sorokiniana GT-1 by optimizing culture conditions or metabolic engineering.
作者
祝棉棉
赵亮
张虎
王红霞
胡强
韩丹翔
ZHU Mian-Mian;ZHAO Liang;ZHANG Hu;WANG Hong-Xia;HU Qiang;HAN Dan-Xiang(Center for Microalgal Biotechnology and Biofuels,Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan 430072,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《水生生物学报》
CAS
CSCD
北大核心
2021年第3期473-486,共14页
Acta Hydrobiologica Sinica
基金
中国科学院重点部署项目(ZDRW-ZS-2017-2)资助。
关键词
小球藻
蛋白质
营养转换
代谢调控
转录组
Chlorella
Protein
Trophic transition
Metabolic regulation
Transcriptome
