A Mycoplasma gallisepticum Glycerol ABC Transporter Involved in Pathogenicity

Abstract

MalF has been shown to be required for virulence in the important avian pathogen Mycoplasma gallisepticum. To characterise the function of MalF, predicted to be part of putative ABC transporter, we compared metabolite profiles of a mutant with a transposon inserted in malF (MalF-deficient ST mutant 04-1; ΔmalF) with those of wild type bacteria using GC/MS and LC/MS. Of those substrates likely to be transported by an ABC transport system, glycerol was detected at significantly lower abundance in the ΔmalF mutant, when compared to the wild type. Stable isotope labelling using [U-13C] glycerol and RT-qPCR analysis indicated that MalF was responsible for import of glycerol into M. gallisepticum and that, in the absence of MalF, the transcription of gtsA, which encodes a second transporter, GtsA, was upregulated, potentially to increase import of glycerol-3-phosphate into the cell to compensate for the loss of MalF. The loss of MalF appeared to have a global effect on glycerol metabolism, suggesting that it may also play a regulatory role, and cellular morphology was also affected, indicating that the change to glycerol metabolism may have a broader effect on cellular organisation. Overall, this study suggests that the reduced virulence of the ΔmalF mutant is due to perturbed glycerol uptake and metabolism, and that the operon including malF should be reannotated to golABC to reflect its function in glycerol transport. Importance Many mycoplasmas are pathogenic and cause disease in human and animals. M. gallisepticum causes chronic respiratory disease in chickens and infectious sinusitis in turkeys, resulting in economic losses in poultry industries throughout the world. To expand our knowledge about the pathogenesis of mycoplasma infections requires better understanding about the specific gene functions of these bacteria. In this study, we have characterised the metabolic function of a protein involved in pathogenicity of M. gallisepticum, as well as its effect on expression of selected genes, cell phenotype and H2O2 production. This study is a key step forward in understanding why this protein plays a key role in virulence in chickens. This study also emphasises the importance offunctional characterisation of mycoplasma proteins, using tools such as metabolomics, as prediction of function based on homology to other bacterial proteins is not always accurate.

Baicalin ameliorates Mycoplasma gallisepticum-induced inflammatory injury via inhibiting STIM1-regulated ceramide accumulation in DF-1 cells

“…In addition, MG is a prokaryote and does not possess organelles capable of synthesizing sphingolipids ( Chatterjee et al, 2021 ). The MG genome encodes numerous nutrient transport systems that help MG acquire lipids and other nutrients from the host ( Chatterjee et al, 2021 ; Mahdizadeh et al, 2021 ). Further studies are required in order to determine which transport system is employed by MG in order to obtain ceramide from the host.…”

“…The Mycoplasma gallisepticum ( MG ) is one of the most important avian Mycoplasma species in the poultry industry ( Mahdizadeh et al, 2021 ). It is well documented that MG causes chronic respiratory disease in chickens that contribute to reduced weight gain of broilers and egg production of layers ( Ishfaq et al, 2020 ).…”

“…Mycoplasma are the smallest prokaryote microorganisms that are genome-reduced bacteria with a parasitic lifestyle, resulting in a dependence on the hosts for metabolic requirement ( Ishfaq et al, 2019b ; Mahdizadeh et al, 2021 ). Sphingolipids metabolites are one of the major classes of host metabolites and key constituents of the plasma membranes ( Leier et al, 2020 ).…”

Genomic Diversity of a Globally Used, Live Attenuated Mycoplasma Vaccine

“…Hence, this protein is likely to be involved in MS-H fitness and pathogenesis. It is worth mentioning that many mycoplasma genomes encode several putative nutrient transporters, meaning that their functions are not always reliably predictable based on sequence similarity with proteins encoded by homologous genes in other bacteria and need to be experimentally validated ( 33 ).…”

Hydroxytyrosol mitigates Mycoplasma gallisepticum-induced pulmonary injury through downregulation of the NF-κB/NLRP3/IL-1β signaling pathway in chicken

“…Its direct mortality is not high; however, it is difficult to cure completely ( Ghanem et al, 2018 ). It is often coinfected with pathogens such as those causing Newcastle disease and infectious rhinitis, infectious bronchitis virus, or Escherichia coli , leading to the aggravation of respiratory symptoms and increased mortality in infected chickens ( Mahdizadeh et al, 2021 ). MG infection seriously affects the weight gain, growth, development, and egg production rate in chicken, causing significant economic losses to commercial poultry breeding and production operations.…”