AUTHOR=Huang Li , Liu Mafeng , Zhu Dekang , Xie Li , Huang Mi , Xiang Chen , Biville Francis , Jia Renyong , Chen Shun , Zhao Xinxin , Yang Qiao , Wu Ying , Zhang Shaqiu , Huang Juan , Ou Xumin , Mao Sai , Gao Qun , Sun Di , Tian Bin , Wang Mingshu , Cheng Anchun 

TITLE=Natural Transformation of Riemerella columbina and Its Determinants

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.634895

DOI=10.3389/fmicb.2021.634895

ISSN=1664-302X

ABSTRACT=<p>In a previous study, it was shown that <italic>Riemerella anatipestifer</italic>, a member of <italic>Flavobacteriaceae</italic>, is naturally competent. However, whether natural competence is universal in <italic>Flavobacteriaceae</italic> remains unknown. In this study, it was shown for the first time that <italic>Riemerella columbina</italic> was naturally competent in the laboratory condition; however, <italic>Flavobacterium johnsoniae</italic> was not naturally competent under the same conditions. The competence of <italic>R. columbina</italic> was maintained throughout the growth phases, and the transformation frequency was highest during the logarithmic phase. A competition assay revealed that <italic>R. columbina</italic> preferentially took up its own genomic DNA over heterologous DNA. The natural transformation frequency of <italic>R. columbina</italic> was significantly increased in GCB medium without peptone or phosphate. Furthermore, natural transformation of <italic>R. columbina</italic> was inhibited by 0.5 mM EDTA, but could be restored by the addition of CaCl<sub>2</sub>, MgCl<sub>2</sub>, ZnCl<sub>2</sub>, and MnCl<sub>2</sub>, suggesting that these divalent cations promote the natural transformation of <italic>R. columbina</italic>. Overall, this study revealed that natural competence is not universal in <italic>Flavobacteriaceae</italic> members and triggering of competence differs from species to species.</p>