Comparative genomic analysis of two-component regulatory proteins in Pseudomonas syringae.
BACKGROUND
Pseudomonas syringae is a widespread bacterial plant pathogen, and strains of P. syringae may be assigned to different pathovars based on host specificity among different plant species. The genomes of P. syringae pv. syringae (Psy) B728a, pv. tomato (Pto) DC3000 and pv. phaseolicola (Pph) 1448A have been recently sequenced providing a major resource for comparative genomic analysis. A mechanism commonly found in bacteria for signal transduction is the two-component system (TCS), which typically consists of a sensor histidine kinase (HK) and a response regulator (RR). P. syringae requires a complex array of TCS proteins to cope with diverse plant hosts, host responses, and environmental conditions.


RESULTS
Based on the genomic data, pattern searches with Hidden Markov Model (HMM) profiles have been used to identify putative HKs and RRs. The genomes of Psy B728a, Pto DC3000 and Pph 1448A were found to contain a large number of genes encoding TCS proteins, and a core of complete TCS proteins were shared between these genomes: 30 putative TCS clusters, 11 orphan HKs, 33 orphan RRs, and 16 hybrid HKs. A close analysis of the distribution of genes encoding TCS proteins revealed important differences in TCS proteins among the three P. syringae pathovars.


CONCLUSIONS
In this article we present a thorough analysis of the identification and distribution of TCS proteins among the sequenced genomes of P. syringae. We have identified differences in TCS proteins among the three P. syringae pathovars that may contribute to their diverse host ranges and association with plant hosts. The identification and analysis of the repertoire of TCS proteins in the genomes of P. syringae pathovars constitute a basis for future functional genomic studies of the signal transduction pathways in this important bacterial phytopathogen.
Lavín
José L
JL
Departamento de Producción Agraria, Universidad Pública de Navarra, 31006 Pamplona, Spain. jluis.lavin@unavarra.es
Kiil
Kristoffer
K
Resano
Ohiana
O
Ussery
David W
DW
Oguiza
José A
JA
D001426:Bacterial Proteins / Q000235:genetics*; D002630:Chemotactic Factors; D002874:Chromosome Mapping; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D000071677:Histidine Kinase; D006790:Host-Parasite Interactions / Q000235:genetics; D008954:Models, Biological; D005810:Multigene Family / Q000235:genetics; D011494:Protein Kinases / Q000145:classification / Q000235:genetics; D044224:Pseudomonas syringae / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
D001426:Bacterial Proteins; D002630:Chemotactic Factors; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase