Bordetella bronchiseptica diguanilate cyclase BdcA regulates motility and is involved in transmission between hosts

ZACCA, FEDERICO; TAYLOR, DAWN; O'TOOLE, GEORGE A.; BELHART, KEILA; AMBROSIS, NICOLÁS; DAHLSTROM, KURT M.; SISTI, FEDERICO; GUTIERREZ, MARÍA DE LA PAZ; CARTELLE GESTAL, MONICA; HARVILL, ERIC T.; FERNÁNDEZ, JULIETA

JOURNAL OF BACTERIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington; Año: 2019

0021-9193

Bacteria can be motile and planktonic or, alternatively, sessile and participating in the biofilm mode of growth. The transition between these lifestyles can be regulated by a second messenger, c-di-GMP.High intracellular c-di-GMP concentration correlates with biofilm formation and motility inhibition in most bacteria, including Bordetella bronchiseptica, which causes respiratory-tract infections in mammals and forms biofilms in infected mice. We previously described the diguanylate cyclase BdcA as involved in c-di-GMP synthesis and motility regulation in B. bronchiseptica; here we further describe the mechanism whereby BdcA is able to regulate motility and biofilm formation. Amino acid replacement of GGDEF with GGAAF in BdcA is consistent with the conclusion that diguanylate cyclase activity is necessary for biofilm formation and motility regulation, although we were unable to confirm the stability of the mutant protein. In the absence of the bdcA gene, B. bronchiseptica showed enhanced motility, strengthening the hypothesis that BdcA regulates motility in B. bronchiseptica. We showed that c-di-GMP-mediated motility inhibition involved regulation of flagellin expression, ashigh c-di-GMP levels achieved by expressing BdcA significantly reduced the level of flagellin protein. We also demonstrated that protein BB2109 is necessary for BdcA activity, motility inhibition,and biofilm formation. Finally, absence of the bdcA gene affected bacterial infection, implicating BdcA regulated functions as important for bacterial host interactions. This work supports a role for c-di-GMP in biofilm formation and motility regulation in B. bronchiseptica, as well as an impact on pathogenesis.