Influence of the ferric uptake regulator (Fur) protein on pathogenicity in Pectobacterium carotovorum subsp. brasiliense

Pectobacterium carotovorum subsp. carotovorum strain PccS1, a bacterial pathogen causing soft rot disease of Zantedeschia elliotiana (colored calla), was investigated for virulence genes induced by the host plant. Using a promoter-trap transposon (mariner), we obtained 500 transposon mutants showing kanamycin resistance dependent on extract of Z. elliotiana. One of these mutants, PM86, exhibited attenuated virulence on both Z. elliotiana and Brassica rapa subsp. pekinensis. The growth of PM86 was also reduced in minimal medium (MM), and the reduction was restored by adding plant extract to the MM. The gene containing the insertion site was identified as rplY. The deletion mutant ΔrplY, exhibited reduced virulence, motility and plant cell wall-degrading enzyme production but not biofilm formation. Analysis of gene expression and reporter fusions revealed that the rplY gene in PccS1 is up-regulated at both the transcriptional and the translational levels in the presence of plant extract. Our results suggest that rplY is induced by Z. elliotiana extract and is crucial for virulence in P. carotovorum subsp. carotovorum.

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Ferric uptake regulator (Fur) reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis in Escherichia coli

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014814 ◽

2020 ◽

Vol 295 (46) ◽

pp. 15454-15463 ◽

Cited By ~ 1

Author(s):

Chelsey R. Fontenot ◽

Homyra Tasnim ◽

Kathryn A. Valdes ◽

Codrina V. Popescu ◽

Huangen Ding

Keyword(s):

Escherichia Coli ◽

Iron Content ◽

Iron Homeostasis ◽

Ferric Uptake Regulator ◽

Intracellular Iron ◽

Free Iron ◽

E Coli ◽

Genes Encoding ◽

Fur Protein ◽

Mutant Cells

The ferric uptake regulator (Fur) is a global transcription factor that regulates intracellular iron homeostasis in bacteria. The current hypothesis states that when the intracellular “free” iron concentration is elevated, Fur binds ferrous iron, and the iron-bound Fur represses the genes encoding for iron uptake systems and stimulates the genes encoding for iron storage proteins. However, the “iron-bound” Fur has never been isolated from any bacteria. Here we report that the Escherichia coli Fur has a bright red color when expressed in E. coli mutant cells containing an elevated intracellular free iron content because of deletion of the iron–sulfur cluster assembly proteins IscA and SufA. The acid-labile iron and sulfide content analyses in conjunction with the EPR and Mössbauer spectroscopy measurements and the site-directed mutagenesis studies show that the red Fur protein binds a [2Fe-2S] cluster via conserved cysteine residues. The occupancy of the [2Fe-2S] cluster in Fur protein is ∼31% in the E. coli iscA/sufA mutant cells and is decreased to ∼4% in WT E. coli cells. Depletion of the intracellular free iron content using the membrane-permeable iron chelator 2,2´-dipyridyl effectively removes the [2Fe-2S] cluster from Fur in E. coli cells, suggesting that Fur senses the intracellular free iron content via reversible binding of a [2Fe-2S] cluster. The binding of the [2Fe-2S] cluster in Fur appears to be highly conserved, because the Fur homolog from Hemophilus influenzae expressed in E. coli cells also reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis.

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Antagonismo direto e biocontrole da podridão-mole-do-tomateiro pelo uso de procariotas

Pesquisa Agropecuária Brasileira ◽

10.1590/s0100-204x2009000300015 ◽

2009 ◽

Vol 44 (3) ◽

pp. 327-330 ◽

Cited By ~ 3

Author(s):

Victor Rafael Barra ◽

Reginaldo da Silva Romeiro ◽

Flávio Augusto de Oliveira Garcia ◽

Andréa Bittencourt Moura ◽

Harllen Sandro Alves Silva ◽

...

Keyword(s):

Lycopersicon Esculentum ◽

Pectobacterium Carotovorum ◽

Lycopersicon Esculentum Mill ◽

Carotovorum Subsp

O objetivo deste trabalho foi avaliar procariotas quanto ao potencial de antagonismo direto para o biocontrole da podridão-mole-do-tomateiro (Pectobacterium carotovorum subsp. carotovorum). Avaliaram-se 45 isolados bacterianos pelo teste de antibiose contra o patógeno. Foram feitos dois ensaios em que sementes de tomate (Lycopersicon esculentum Mill.) cv. Santa Clara foram infectadas com isolados antagônicos. As mudas foram transplantadas para solos infestados com suspensões de propágulos P. carotovorum com OD540 de 0,45 e 0,65. Os antagonistas UFV-0005, UFV-043, UFV-BF112 e UFV-0006 foram eficientes em proteger plantas de tomateiro contra a podridão-mole.

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