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Oxygen‐dependent regulation of c‐di‐ GMP synthesis by SadC controls alginate production in P seudomonas aeruginosa
Author(s) -
Schmidt Annika,
Hammerbacher Anna Silke,
Bastian Mike,
Nieken Karen Jule,
Klockgether Jens,
Merighi Massimo,
Lapouge Karine,
Poschgan Claudia,
Kölle Julia,
Acharya K. Ravi,
Ulrich Martina,
Tümmler Burkhard,
Unden Gottfried,
Kaever Volkhard,
Lory Stephen,
Haas Dieter,
Schwarz Sandra,
Döring Gerd
Publication year - 2016
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13208
Subject(s) - biology , oxygen , activator (genetics) , biochemistry , microbiology and biotechnology , gene , chemistry , organic chemistry
Summary P seudomonas aeruginosa produces increased levels of alginate in response to oxygen‐deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis‐induced alginate production by planktonic PAO 1 requires the diguanylate cyclase ( DGC ) SadC , previously identified as a regulator of surface‐associated lifestyles. Furthermore, we found that the gene products of PA 4330 and PA 4331, located in a predicted operon with sadC , have a major impact on alginate production: deletion of PA 4330 ( odaA , for oxygen‐dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA 4331 ( odaI , for oxygen‐dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA , which did not significantly affect DGC activity of SadC , OdaI inhibited c‐di‐ GMP production by SadC . Our data indicate that SadC , OdaA and OdaI are components of a novel response pathway of P . aeruginosa that regulates alginate synthesis in an oxygen‐dependent manner.