Sun H, Zhang J, Liu W, E W, Wang X, Li H, Cui Y, Zhao D, Liu K, Du B, Ding Y, Wang C. Identification and combinatorial engineering of indole-3-acetic acid synthetic pathways in Paenibacillus polymyxa.
BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022;
15:81. [PMID:
35953838 PMCID:
PMC9367139 DOI:
10.1186/s13068-022-02181-3]
[Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 08/05/2022] [Indexed: 11/22/2022]
Abstract
Background
Paenibacillus polymyxa is a typical plant growth-promoting rhizobacterium (PGPR), and synthesis of indole-3-acetic acid (IAA) is one of the reasons for its growth-promoting capacity. The synthetic pathways of IAA in P. polymyxa must be identified and modified.
Results
P. polymyxa SC2 and its spontaneous mutant SC2-M1 could promote plant growth by directly secreting IAA. Through metabonomic and genomic analysis, the genes patA, ilvB3, and fusE in the native IPyA pathway of IAA synthesis in strain SC2-M1 were predicted. A novel strong promoter P04420 was rationally selected, synthetically analyzed, and then evaluated on its ability to express IAA synthetic genes. Co-expression of three genes, patA, ilvB3, and fusE, increased IAA yield by 60% in strain SC2-M1. Furthermore, the heterogeneous gene iaam of the IAM pathway and two heterogeneous IPyA pathways of IAA synthesis were selected to improve the IAA yield of strain SC2-M1. The genes ELJP6_14505, ipdC, and ELJP6_00725 of the entire IPyA pathway from Enterobacter ludwigii JP6 were expressed well by promoter P04420 in strain SC2-M1 and increased IAA yield in the engineered strain SC2-M1 from 13 to 31 μg/mL, which was an increase of 138%.
Conclusions
The results of our study help reveal and enhance the IAA synthesis pathways of P. polymyxa and its future application.
Supplementary Information
The online version contains supplementary material available at 10.1186/s13068-022-02181-3.
Verifying an entire native IPyA pathway of IAA synthesis in P. polymyxa.
Introducing heterologous IAM and IPyA pathways of IAA synthesis to P. polymyxa.
Selecting and analyzing a novel strong promoter P04420 to express IAA synthesis genes.
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