Potentiation of concurrent expression of lipogenic genes by novel strong promoters in the oleaginous microalga Phaeodactylum tricornutum

• Published in: Biotechnology and bioengineering Vol. 116; no. 11; pp. 3006 - 3015
• Main Authors: Zou, Li‐Gong, Balamurugan, Srinivasan, Zhou, Tian‐Bao, Chen, Jia‐Wen, Li, Da‐Wei, Yang, Wei‐Dong, Liu, Jie‐Sheng, Li, Hong‐Ye
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.11.2019
• Subjects: Algae; Combinatorial analysis; Desaturase; Eicosapentaenoic acid; Esters; Fatty acid methyl esters; Fatty acids; Gene expression; Gene sequencing; Genes; lipid overproduction; Lipids; Malic enzyme; microalga; multigene expression; Phaeodactylum tricornutum; Promoters; strong promoter; microalga; Phaeodactylum tricornutum; strong promoter; lipid overproduction; multigene expression
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.27110

There has been growing interest in using microalgae as production hosts for a wide range of value‐added compounds. However, microalgal genetic improvement is impeded by lack of genetic tools to concurrently control multiple genes. Here, we identified two novel strong promoters, designated Pt202 and Pt667, and delineated their potential role on simultaneously driving the expression of key lipogenic genes in Phaeodactylum tricornutum. In silico analyses of the identified promoter sequences predicted the presence of essential core cis elements such as TATA and CAAT boxes. Regulatory role of the promoters was preliminarily assessed by using GUS reporter which demonstrated strong GUS expression. Thereafter, two key lipogenic genes including malic enzyme (PtME) and 5‐desaturase (PtD5b), were overexpressed by the two promoters Pt202 and Pt667, respectively, in P. tricornutum. Combinatorial gene overexpression did not impair general physiological performance, meanwhile neutral lipid content was remarkably increased by 2.4‐fold. GC‐MS analysis of fatty acid methyl esters revealed that eicosapentaenoic acid (EPA; C20:5) was increased significantly. The findings augment a crucial kit to microalgal genetic tools that could facilitate the multiple‐gene expression driven by various promoters, and promote microalgae for industrial bioproduction. There has been growing interest in using microalgae as production hosts for a wide range of value‐added compounds. However, microalgal genetic improvement is impeded by lack of genetic tools to concurrently control multiple genes. Here, we identified two novel strong promoters, designated Pt202 and Pt667, and delineated their potential role on simultaneously driving the expression of key lipogenic genes in Phaeodactylum tricornutum.