Genetic analysis of the cold-sensitive growth phenotype of Burkholderia pseudomallei/thailandensis bacteriophage AMP1

Andrey V Letarov,Maria A Letarova,Pavel A Ivanov,Edouard E Galyov,Martha R J Clokie,Ilya S Belalov

doi:10.1038/s41598-022-07763-7

Abstract

Bacteriophages related to phage Bp_AMP1 are the most widely spread group of phages infecting Burkholderia pseudomallei—the causative agent of melioidosis. These viruses are also infective against the nonpathogenic host Burkholderia thailandensis, allowing experimental work with them without any special safety precautions. The indirect data as well as the results of the mathematical modelling suggest that the AMP1-like viruses may act as natural biocontrol agents influencing the population levels of B. pseudomallei in soil and water habitats in endemic regions. The cold sensitivity of the lytic growth (CSg) of these phages was suggested to be an important feature modulating the effect of viral infection on host populations in nature. We performed genetic analysis to determine the molecular background of the CSg phenotype of the AMP1 phage. The results indicate that CSg is not due to the lack of any function or product missing at low temperature (25 °C) but results in growth inhibition by a phage-encoded temperature-sensitive genetic switch. We identified phage ORF3 and ORF14 to be involved in the genetic determination of this mechanism.

Highlights

Bacteriophages related to phage Bp_AMP1 are the most widely spread group of phages infecting Burkholderia pseudomallei—the causative agent of melioidosis
In previous work, when we assessed phages that infect the important tropical pathogen Burkholderia pseudomallei and the closely related nonpathogenic environmental bacterium Burkholderia thailandensis in the natural environment, we found that AMP1-like viruses were the most ubiquitous and widely spread phage that we could isolate on this host from in natural ecosystems[9]
The cold-sensitive growth (CSg) phenotype of AMP1-related phages is a potentially important feature that may influence the ecology of B. pseudomallei and AMP1-like phages in natural habitats in regions of melioidosis endemism, such as northeastern Thailand

Summary

Introduction

Bacteriophages related to phage Bp_AMP1 are the most widely spread group of phages infecting Burkholderia pseudomallei—the causative agent of melioidosis. These ideas, initially based on our observations from in vitro studies of the bacteria-phage interactions, are supported by mathematical modeling, which suggested that temperature-sensitive switching between supposed lysogeny and lytic development of the AMP1-like phages may cause seasonal variations in bacterial abundance and melioidosis cases observed in some areas of NE Thailand[11,12] If this is the case, understanding the mechanisms of interactions of Burkholderia host with AMP1 phage is clearly important for further analysis of the possible roles of phage infection in B. pseudomallei dynamics in nature

Methods

Results

Conclusion