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The Plant Pathogen Pseudomonas syringae pv. tomato Is Genetically Monomorphic and under Strong Selection to Evade Tomato Immunity.
- Source :
- PLoS Pathogens; Aug2011, Vol. 7 Issue 8, Special section p1-15, 15p
- Publication Year :
- 2011
-
Abstract
- Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen micro evolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP) in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15537366
- Volume :
- 7
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- PLoS Pathogens
- Publication Type :
- Academic Journal
- Accession number :
- 66329082
- Full Text :
- https://doi.org/10.1371/journal.ppat.1002130