Epigenetic Modulating Chemicals Significantly Affect the Virulence and Genetic Characteristics of the Bacterial Plant Pathogen Xanthomonas campestris pv. campestris.

Miroslav Baránek,Milan Špetík,Joanna Puławska,Viera Kováčová,Filip Gazdík,Kateřina Baránková,Aleš Eichmeier

doi:10.3390/genes12060804

Abstract

Epigenetics is the study of heritable alterations in phenotypes that are not caused by changes in DNA sequence. In the present study, we characterized the genetic and phenotypic alterations of the bacterial plant pathogen Xanthomonas campestris pv. campestris (Xcc) under different treatments with several epigenetic modulating chemicals. The use of DNA demethylating chemicals unambiguously caused a durable decrease in Xcc bacterial virulence, even after its reisolation from infected plants. The first-time use of chemicals to modify the activity of sirtuins also showed some noticeable results in terms of increasing bacterial virulence, but this effect was not typically stable. Changes in treated strains were also confirmed by using methylation sensitive amplification (MSAP), but with respect to registered SNPs induction, it was necessary to consider their contribution to the observed polymorphism. The molecular basis of the altered virulence was deciphered by using dualRNA-seq analysis of treated Xcc strains infecting Brassica rapa plants. The results of the present study should promote more intensive research in the generally understudied field of bacterial epigenetics, where artificially induced modification by epigenetic modulating chemicals can significantly increase the diversity of bacterial properties and potentially contribute to the further development of the fields, such as bacterial ecology and adaptation.

Highlights

Epigenetics is the study of alterations in the features of organisms that are not caused by variations in their DNA sequence
The virulence observed for the individual epigenetically treated strains (ETSs) in the second round of inoculations is summarized in Figure 2
The results obtained by using the methylation sensitive amplification (MSAP) method were the impetus for the additional evaluation of the obtained sequencing data, because the low values of similarity coefficients derived from MSAP spectra suggested that another factor, such as SNPs, could play role here

Summary

Introduction

Epigenetics is the study of alterations in the features of organisms that are not caused by variations in their DNA sequence. These kinds typically result from stable shifts in gene expression caused by modifications of the nucleotides in DNA, e.g., methylation, non-coding RNA interference, or alterations in eukaryotic chromatin [1]. The most famous of these factors are DNA-methylation based epigenetic markers, which are able to modify gene expression in both eukaryotic and prokaryotic organisms. The first group is represented by transferases active in restriction-modification (R-M) systems, where the methylation of the specific base inhibits the activity of restriction endonucleases activity and protects the host cell against foreign DNA, e.g., phages [9]. The traditional view of this distinction has begun to change, as more roles for DNMT included in R-M systems are described [11] or solitary DNA methyltransferases show higher abundancy than expected [12]

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Discussion

Conclusion