Transducer-Like Protein in With a Role in Mediating Chemotaxis to Iron and Phosphate.

Chemotaxis-mediated motility enables to navigate through complex environmental gradients and colonize diverse niches. is known to possess several methyl accepting chemotaxis proteins (MCPs), also called transducer-like proteins (Tlps). While the role of some of the Tlps in chemotaxis has been identified, their regulation and role in virulence is still not very clear. Here, we investigated the contribution of Tlp2 to chemotaxis, stress survival and colonization of the chicken gastrointestinal tract. The Δ deletion mutant showed decreased chemotaxis toward aspartate, pyruvate, inorganic phosphate (Pi), and iron (FeSO). Transcriptional analysis of with a promoter fusion reporter assay revealed that the promoter (P ) was induced by Pi and iron, both in the ferrous (Fe) and ferric form (Fe). RT-PCR analysis using overlapping primers indicated that the gene, located immediately downstream of is co-transcribed with . A transcription start site was identified at 53 bp upstream of the start codon. The Δ mutant showed decreased colonization of the chicken gastrointestinal tract. Collectively, our findings revealed that the plays a role in pathogenesis and colonization in the chicken host and its expression is regulated by iron.