Genome-scale Solanum spp.-Ralstonia solanacearum interactome reveals candidate determinants for host specificity and environmental adaptation

A functional analysis of an 11-kb-long region of the genome of the plant-pathogenic bacterium Ralstonia solanacearum, previously identified as an alternative codon usage region (ACUR), reveals that it was probably acquired through horizontal gene transfer. This ACUR encodes an insertion sequence and eight potential proteins, one of which is partially homologous with a host-specificity factor from a plant-pathogenic Erwinia sp., and another, PopP1, which is homologous to members of the YopJ/AvrRxv family of type III-secreted bacterial effectors controlling interaction between bacteria and their hosts. The analysis of mutants affecting all except one of the genes identified in the ACUR showed that only the popP1-deficient strain had an altered phenotype in plant infection tests. This mutant strain became pathogenic to a Petunia line that is resistant to the wild-type strain. Therefore, popP1 behaves as a typical avirulence gene. We demonstrate that PopP1 protein is secreted and that secretion of this protein requires a functional type III-secretion pathway. In contrast to the structural genes for other type III-secreted proteins identified in R. solanacearum, transcription of the popP1 gene is not coregulated with transcription of hrp genes but is constitutive.

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Comparative genomic analysis of Ralstonia solanacearum reveals candidate genes for host specificity

BMC Genomics ◽

10.1186/s12864-015-1474-8 ◽

2015 ◽

Vol 16 (1) ◽

Cited By ~ 43

Author(s):

Florent Ailloud ◽

Tiffany Lowe ◽

Gilles Cellier ◽

David Roche ◽

Caitilyn Allen ◽

...

Keyword(s):

Candidate Genes ◽

Host Specificity ◽

Ralstonia Solanacearum ◽

Genomic Analysis ◽

Comparative Genomic Analysis ◽

Comparative Genomic

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Potassium Phosphite Modulated the Soil Microbiome and Enriched the Antagonistic Bacteria Streptomyces Coelicoflavus and Paenibacillus Favisporus to Inhibit the Tomato Pathogen Ralstonia Solanacearum Synergistically

10.21203/rs.3.rs-143372/v1 ◽

2021 ◽

Author(s):

Lv Su ◽

Xingxia Mo ◽

Juan Sun ◽

Pengfei Qiu ◽

Ruifu Zhang ◽

...

Keyword(s):

Ralstonia Solanacearum ◽

Soil Microbiome ◽

Antagonistic Bacteria ◽

Agricultural Chemicals ◽

Bacterial Composition ◽

Synthetic Genes ◽

Potassium Phosphite ◽

Soil Bacterial ◽

Tomato Pathogen ◽

Genome Scale

Abstract Background: Application of certain agricultural chemicals could modulate the soil microbiome and induce potential antagonistic microbes. However, the specific selective effects of agricultural chemicals on soil bacterial functions and their co-occurrences are not well understood, and no studies have verified that the enriched potential antagonistic microbes could enhance the antagonistic functions of the soil microbiome.Results: Here, the effects of potassium phosphite (KP), an environment-friendly agricultural chemical, on the soil bacterial composition, co-occurrences and antagonistic functions were determined, and the potential antagonistic bacteria against the tomato bacterial wilt pathogen Ralstonia solanacearum were isolated to test their functions and associations among these strains. Our results showed that application of KP enriched Bacillus, Paenibacillus and Streptomyces. The positive links among the OTUs belonging to these genera were increased, and positive associations between these OTUs and predicted genes related to antagonistic substance production were revealed. Two strains, Streptomyces coelicoflavus F13 and Paenibacillus favisporus Y7, were isolated, and they inhibited the growth of R. solanacearum. Genomic sequencing showed that both strains harboured streptomycin synthetic genes, and P. favisporus Y7 also contained surfactin synthetic gene cluster. Synergistic inhibition of R. solanacearum growth by P. favisporus Y7 and S. coelicoflavus F13 was observed in soil. Genome-scale metabolic modelling showed that dextrin and lactic acid were potential cross-feeding metabolites. In addition, the KP-modulated soil microbiome could suppress R. solanacearum growth. Conclusions: Our results highlight that a KP-modulated soil microbiome has considerable potential for biocontrol and indicate a new mechanism for the inhibition of R. solanacearum by KP-enriched soil bacteria.

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