Gibberellic acid overproduction in Fusarium fujikuroi using regulatory modification and transcription analysis

• Published in: Applied microbiology and biotechnology 2023-05, Vol.107 (9), p.3071-3084
• Main Authors: Wang, Haonan, Ke, Xia, Jia, Rui, Huang, Lianggang, Liu, Zhiqiang, Zheng, Yuguo
• Format: Article
• Language: English
• Subjects: Agricultural engineering; Analysis; Applied Microbial and Cell Physiology; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Chromosomes; Cytochrome P450; Cytochromes P450; Diterpenes; Fusarium; Fusarium - genetics; Fusarium - metabolism; Fusarium fujikuroi; Genes; Genetic transcription; Gibberellic acid; Gibberellins; Gibberellins - metabolism; Identification and classification; Industrial production; Life Sciences; Metabolic engineering; Metabolism; Microbial Genetics and Genomics; Microbiology; Microorganisms; Nitrogen; Overexpression; Plant growth; Plant Growth Regulators - metabolism; Plant hormones; Properties; Transcriptomes
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-023-12498-0

Gibberellic acid (GA 3 ), one of the natural diterpenoids produced by Fusarium fujikuroi , serves as an important phytohormone in agriculture for promoting plant growth. Presently, the metabolic engineering strategies for increasing the production of GA 3 are progressing slowly, which seriously restricted the advancing of the cost-effective industrial production of GA 3 . In this study, an industrial strain with high-yield GA 3 of F. fujikuroi was constructed by metabolic modification, coupling with transcriptome analysis and promoter engineering. The over-expression of AreA and Lae1, two positive factors in the regulatory network, generated an initial producing strain with GA 3 production of 2.78 g L −1 . Compared with a large abundance of transcript enrichments in the GA 3 synthetic gene cluster discovered by the comparative transcriptome analysis, geranylgeranyl pyrophosphate synthase 2 (Ggs2), and cytochrome P450-3 genes, two key genes that respectively participated in the initial and final step of biosynthesis, were identified to be downregulated when the highest GA 3 productivity was obtained. Employing with a nitrogen-responsive bidirectional promoter, the two rate-limiting genes were dynamically upregulated, and therefore, the production of GA 3 was increased to 3.02 g L −1 . Furthermore, the top 20 upregulated genes were characterized in GA 3 over-production, and their distributions in chromosomes suggested potential genomic regions with a high transcriptional level for further strain development. The construction of a GA 3 high-yield-producing strain was successfully achieved, and insights into the enriched functional transcripts provided novel strain development targets of F. fujikuroi , offering an efficient microbial development platform for industrial GA 3 production. Key points • Global regulatory modification was achieved in F. fujikuroi for GA 3 overproduction. • Comparative transcriptome analysis revealed bottlenecks in GA specific-pathway. • A dynamically nitrogen-regulated bidirectional promoter was cloned and employed. Graphical Abstract