AUTHOR=Tan Li , Huang Yuyang , Shang Weilong , Yang Yi , Peng Huagang , Hu Zhen , Wang Yuting , Rao Yifan , Hu Qiwen , Rao Xiancai , Hu Xiaomei , Li Ming , Chen Kaisen , Li Shu 

TITLE=Accessory Gene Regulator (agr) Allelic Variants in Cognate Staphylococcus aureus Strain Display Similar Phenotypes

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.700894

DOI=10.3389/fmicb.2022.700894

ISSN=1664-302X

ABSTRACT=<p>The <underline>a</underline>ccessory <underline>g</underline>ene <underline>r</underline>egulator (<italic>agr</italic>) quorum-sensing system is an important global regulatory system of <italic>Staphylococcus aureus</italic> and contributes to its pathogenicity. The <italic>S. aureus agr</italic> system is divided into four <italic>agr</italic> groups based on the amino acid polymorphisms of AgrB, AgrD, and AgrC. The <italic>agr</italic> activation is group-specific, resulting in variations in <italic>agr</italic> activity and pathogenicity among the four <italic>agr</italic> groups. Strains with divergent <italic>agr</italic> system always have different phenotypes. In the present report, we, respectively, exchanged the <italic>agr</italic> system of a certain <italic>S. aureus</italic> with other three <italic>agr</italic> alleles and assessed the corresponding phenotypes of these congenic strains. Replacement of the <italic>agr</italic> system led to significant variations in hemolytic activity, protein expression, and virulence gene expression comparing with that of the parental strain. Interestingly, we found that the biological characteristics of these <italic>agr</italic> congenic strains in the same strain background were highly similar to each other, and the allele-dependent differences of the <italic>agr</italic> systems were weakened. These findings indicate that the allele-dependent <italic>agr</italic> predilections of <italic>S. aureus</italic> are determined by some factors in addition to the polymorphisms of AgrB, AgrD, and AgrC. Future studies may reveal the novel mechanism to improve our understanding of the <italic>agr</italic> network.</p>