文献类型：期刊文献

英文题名：Comparative transcriptome analyses of oleaginous Botryococcus braunii race A reveal significant differences in gene expression upon cobalt enrichment 06 Biological Sciences 0601 Biochemistry and Cell Biology

作者：Cheng, Pengfei[1]; Zhou, Chengxu[1]; Wang, Yan[1]; Xu, Zhihui[1]; Xu, Jilin[1]; Zhou, Dongqing[2,3]; Zhang, Yinghui[2,3]; Wu, Haizhen[2,3]; Zhang, Xuezhi[4]; Liu, Tianzhong[5]; Tang, Ming[6]; Yang, Qiyong[6]; Yan, Xiaojun[7]; Fan, Jianhua[2,3]

机构：[1] College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, 315211, China; [2] State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China; [3] Department of Applied Biology, East China University of Science and Technology, Shanghai, 200237, China; [4] Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; [5] Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China; [6] Poyang Lake Eco-economy Research Center, Jiujiang University, Jiujiang, 332000, China; [7] Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, 818 Fenghua Road, Ningbo, 315211, China

年份：2018

卷号：11

期号：1

外文期刊名：Biotechnology for Biofuels

收录：EI(收录号：20185206288346)

语种：英文

外文关键词：Physiology - Biochemistry - Hydrocarbons - Metabolism - Photosynthesis - Fatty acids - Gene expression - Carbon - Biosynthesis - Cytology - Physiological models

摘要：Background: Botryococcus braunii is known for its high hydrocarbon content, thus making it a strong candidate feedstock for biofuel production. Previous study has revealed that a high cobalt concentration can promote hydrocarbon synthesis and it has little effect on growth of B. braunii cells. However, mechanisms beyond the cobalt enrichment remain unknown. This study seeks to explore the physiological and transcriptional response and the metabolic pathways involved in cobalt-induced hydrocarbon synthesis in algae cells. Results: Growth curves were similar at either normal or high cobalt concentration (4.5 mg/L), suggesting the absence of obvious deleterious effects on growth introduced by cobalt. Photosynthesis indicators (decline in Fv/Fm ratio and chlorophyll content) and reactive oxygen species parameters revealed an increase in physiological stress in the high cobalt concentration. Moreover, cobalt enrichment treatment resulted in higher crude hydrocarbon content (51.3% on day 8) compared with the control (43.4% on day 8) throughout the experiment (with 18.2% improvement finally). Through the de novo assembly and functional annotation of the B. braunii race A SAG 807-1 transcriptome, we retrieved 196,276 non-redundant unigenes with an average length of 1086 bp. Of the assembled unigenes, 89,654 (45.7%), 42,209 (21.5%), and 32,318 (16.5%) were found to be associated with at least one KOG, GO, or KEGG ortholog function. In the early treatment (day 2), the most strongly upregulated genes were those involved in the fatty acid biosynthesis and metabolism and oxidative phosphorylation, whereas the most downregulated genes were those involved in carbohydrate metabolism and photosynthesis. Genes that produce terpenoid liquid hydrocarbons were also well identified and annotated, and 21 (or 29.2%) were differentially expressed along the cobalt treatment. Conclusions: Botryococcus braunii SAG 807-1 can tolerate high cobalt concentration and benefit from hydrocarbon accumulation. The time-course expression profiles for fatty acid biosynthesis, metabolism, and TAG assembly were obtained through different approaches but had equally satisfactory results with the redirection of free long-chain fatty acid and VLCFA away from TAG assembly and oxidation. These molecules served as precursors and backbone supply for the fatty acid-derived hydrocarbon accumulation. These findings provide a foundation for exploiting the regulation mechanisms in B. braunii race A for improved photosynthetic production of hydrocarbons. ? 2018 The Author(s).