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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sugarbeet Research » Research » Publications at this Location » Publication #420194
Research Project: Improving Sugarbeet Productivity and Sustainability through Genetic, Genomic, Physiological, and Phytopathological Approaches

Location: Sugarbeet Research

Title: Polyyne production is regulated by the transcriptional regulators PgnC and GacA in Pseudomonas protegens Pf-5

Author
item MWANZA, CHISECHE - Montana State University
item PURNAMASARI, MARIA - Montana State University
item Back, Daniel
item PRIHATNA, CAHYA - Montana State University
item PHILMUS, BENJAMIN - Oregon State University
item ALMABRUK, KHALED - Oregon State University
item MAHMUD, TAIFO - Oregon State University
item YE, LUMENG - Genepioneer Biotechnologies
item Bolton, Melvin
item WU, XIAOGNAG - Guangxi Academy Of Agricultural Sciences
item LOPER, JOYCE - Oregon State University
item QUING, YAN - Montana State University

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Polyynes are natural products that possess potent antimicrobial properties and have been shown to inhibit the growth of agriculturally relevant pathogens, making them promising candidates for management of crop disease. To date, various organisms such as bacteria, fungi, insects, and plants have been reported to produce polyynes. Although the biosynthesis of polyynes is well documented, there is little known about the molecular mechanisms that regulate the production of these compounds. This study reveals that their production is regulated both locally within the gene cluster and globally under a broad regulatory system at both the transcription and translation stages of gene expression. In addition, this study highlights their efficacy against a variety of bacteria, including the casual agents of bacterial leaf spot diseases Xanthomonas translucens and Pseudomonas syringae. The information gained from this study is useful for agricultural researchers to aid in the development of biocontrol strategies effective against a variety of crop diseases.

Technical Abstract: Polyyne compounds produced by bacteria have promising applications in agriculture and medicine due to their potent antimicrobial activities. Biosynthetic genes for polyyne production have been identified in Pseudomonas and Burkholderia spp. However, the molecular mechanism underlying the regulation of polyyne production in bacteria remain largely unknown. In this study, we used the soil bacterium Pseudomonas protegens Pf-5, which was recently reported to produce a polyyne called protegencin, as a model to investigate regulation of bacterial polyyne production. Our results show that Pf-5 controls polyyne production at both the pathway-specific level and at a higher global level. Mutation of pgnC, a putative transcriptional regulatory gene located in the polyyne biosynthetic gene cluster, abolished the production of polyyne. Gene expression analysis revealed that PgnC directly activates the promoter of polyyne biosynthetic genes. Production of polyyne also requires the global regulator GacA. Mutation of gacA decreased the translation of PgnC, which is consistent with the result that pgnC leader mRNA bound directly to RsmE, an RNA-binding protein negatively regulated by GacA. These results suggest that GacA induces the expression of PgnC regulator which in turn activates polyyne biosynthesis. Additionally, we tested the inhibition effect of Pf-5 derivative strains and found that the polyyne-producing strain, but not the polyyne-nonproducing strain, could inhibit a broad spectrum of bacteria including both Gram-negative and Gram-positive bacteria.