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

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]Ningbo Univ, Coll Food & Pharmaceut Sci, Ningbo 315211, Zhejiang, Peoples R China;[2]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China;[3]East China Univ Sci & Technol, Dept Appl Biol, Shanghai 200237, Peoples R China;[4]Chinese Acad Sci, Inst Hydrobiol, Wuhan 430072, Hubei, Peoples R China;[5]Chinese Acad Sci, Qingdao Inst Bioenergy & Bioproc Technol, Key Lab Biofuels, Qingdao 266101, Peoples R China;[6]Jiujiang Univ, Poyang Lake Ecoecon Res Ctr, Jiujiang 332000, Peoples R China;[7]Ningbo Univ, Key Lab Marine Biotechnol Zhejiang Prov, 818 Fenghua Rd, Ningbo 315211, Zhejiang, Peoples R China

年份：2018

卷号：11

外文期刊名：BIOTECHNOLOGY FOR BIOFUELS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000453684700002)】；

基金：This work was sponsored by National Natural Science Foundation of China 31560724 and 31872608, the China Postdoctoral Science Foundation 2017T100583 and 2016M600616, the Natural Science Foundation of Jiangxi Province 20171BAB214014, the Natural Science Foundation of Shanghai 18ZR1410100 and 17ZR1406700, Shanghai Pujiang Program 18PJD008, Open Funding Project of the State Key Laboratory of Bioreactor Engineering 2018021, Key Laboratory of Poyang Lake Ecological Environment and Resource Development PK2017001, and the K. C. Wong Magna Fund in Ningbo University.

语种：英文

外文关键词：Botryococcus braunii; Cobalt treatment; Physiological response; Transcriptome; Regulation mechanism

摘要：BackgroundBotryococcus 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.ResultsGrowth curves were similar at either normal or high cobalt concentration (4.5mg/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 1086bp. 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.ConclusionsBotryococcus 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.