UvrC is required for iron utilization, biofilm formation and virulence.

Abstract

UvrC is a subunit of excinuclease ABC, which mediates nucleotide excision repair (NER) in bacteria. Our previous studies showed that transposon Tn4531 insertion in the UvrC encoding gene Riean_1413 results in reduced biofilm formation bystrain CH3 and attenuates virulence of strain YZb1. In this study, whetherUvrC has some biological functions other than NER was investigated. Firstly, theofstrain Yb2 was in-frame deleted by homologous recombination, generating deletion mutant ΔuvrC, and its complemented strain cΔuvrC was constructed based on-shuttle plasmid pRES. Compared to the wild-type (WT)strain Yb2,deleted mutant ΔuvrC significantly reduced biofilm formation, tolerance to HO- and HOCl-induced oxidative stress, iron utilization, and adhesion to and invasion of duck embryonic hepatocytes, but not its growth curve and proteolytic activity. In addition, animal experiments showed that the LDvalue of ΔuvrC in ducklings was about 13-fold higher than that of the WT, and the bacterial loads in ΔuvrC infected ducklings were significantly lower than those in Yb2-infected ducklings, indicatingdeletion inattenuated virulence. Taken together, the results of this study indicate thatUvrC is required for iron utilization, biofilm formation, oxidative stress tolerance and virulence of strain Yb2, demonstrating multiple functions of UvrC.Deletion ofinYb2 significantly reduced its biofilm formation.deletion led to reduced tolerance to HO- and HOCl-induced oxidative stress.The iron utilization ofdeleted mutant was significantly reduced.Thedeletion inYb2 attenuated its virulence.