Location: Forage Seed and Cereal ResearchTitle: Resistance to two vinylglycine antibiotic analogs is conferred by inactivation of two separate amino acid transporters in Erwinia amylovora
|SMITH, DEREK - University Of Regina|
|BERGBUSCH, NATHANAEL - University Of Regina|
|VERRETT, JENNIFER - University Of Regina|
|WILLIAMS, ASHLEY - University Of Regina|
|STAVRINIDES, JOHN - University Of Regina|
Submitted to: Journal of Bacteriology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2019
Publication Date: 4/9/2019
Citation: Smith, D.D., Bergbusch, N.T., Verrett, J.N., Williams, A.N., Manning, V., Trippe, K.M., Stavrinides, J. 2019. Resistance to two vinylglycine antibiotic analogs is conferred by inactivation of two separate amino acid transporters in Erwinia amylovora. Journal of Bacteriology. 201:e00658-18. https://doi.org/10.1128/JB.00658-18.
Interpretive Summary: As microbes become more resistant to current antibiotics, it is becoming increasingly important to determine the molecular mechanisms that propel and underpin resistance. Erwinia amylovora is the bacterium that causes fire blight, a disease of apples and pears. PNP-1 (formylaminooxyvinylglycine), is a small molecule that has the potential to control the growth of E. amylovora, and therefore control the spread of fire blight. However, studies in the lab show that resistance to PNP-1 evolves quickly. This study investigates the mechanism of resistance and determines that mutations in an asparagine permease are associated with resistance. This study is important because it describes a new mechanism by which microorganisms can acquire antibiotic resistance.
Technical Abstract: Erwinia amylovora is the causal agent of fire blight disease of apple and pear. Antibiotics that are effective against E. amylovora include pantocins, herbicolins, and dapdiamides, and more recently, Pantoea Natural Product 1 (PNP-1) from the bacterial strain Pantoea ananatis BRT175. PNP-1 shares several common characteristics with 4-formylaminooxyvinylglycine (FVG) produced by Pseudomonas fluorescens WH6. Exposure of E. amylovora to either PNP-1 or FVG results in spontaneously resistant mutants, but the mechanism of resistance is currently not known. In this study, we carried out a genome variant analysis of spontaneous E. amylovora mutants, and identified that antibiotic resistance was due to null mutations in the L-asparagine permease, ansP. Heterologous expression of the ansP gene in normally resistant Escherichia coli was sufficient to impart PNP-1 susceptibility, suggesting PNP-1 is imported through this permease. We show that a predicted lysE-like lysine permease that is encoded within the PNP-1 biosynthetic cluster confers a degree of antibiotic resistance in E. amylovora, indicating that this permease is likely responsible for PNP-1 export. This work provides insight into the cellular mechanisms of PNP-1 import and export, and implicates antibiotic exclusion as one mechanism of PNP-1 antibiotic resistance in E. amylovora.