Genetic and structural determinants on iron assimilation pathways in the plant pathogen Xanthomonas citri subsp. citri and Xanthomonas sp.

Abstract

Iron is a vital nutrient to bacteria, not only in the basal metabolism but also for virulent species in infection and pathogenicity at their hosts. Despite its relevance, the role of iron in Xanthomonas citri infection, the etiological agent of citrus canker disease, is poorly understood in contrast to other pathogens, including other members of the Xanthomonas genus. In this review, we present iron assimilation pathways in X. citri including the ones for siderophore production and siderophore-iron assimilation, proven to be key factors to virulence in many organisms like Escherichia coli and Xanthomonas campestris. Based on classical iron-related proteins previously characterized in E. coli, Pseudomonas aeruginosa, and also Xanthomonadaceae, we identified orthologs in X. citri and evaluated their sequences, structural characteristics such as functional motifs, and residues that support their putative functions. Among the identified proteins are TonB-dependent receptors, periplasmic-binding proteins, active transporters, efflux pumps, and cytoplasmic enzymes. The role of each protein for the bacterium was analyzed and complemented with proteomics data previously reported. The global view of different aspects of iron regulation and nutrition in X. citri virulence and pathogenesis may help guide future investigations aiming the development of new drug targets against this important phytopathogen.

Disentangling the Evolutionary History of Feo, the Major Ferrous Iron Transport System in Bacteria

“…Likewise, Fe 2+ transport by Feo can determine the outcomes of bacterial infections within animal and plant hosts in some pathogens ( 2 , 5 ). These include the human intestinal and gastric pathogens Salmonella enterica ( 6 ) and Helicobacter pylori ( 7 ) and plant pathogens such as Xanthomonas species ( 8 , 9 ). Despite its importance in bacterial iron acquisition, the evolution and working mechanism of the Feo system remain poorly understood.…”

A Comprehensive Overview of the Genes and Functions Required for Lettuce Infection by the Hemibiotrophic Phytopathogen Xanthomonas hortorum pv. vitians

“…The organization of these three bfeA -like genes upstream of xss is strikingly similar to what was observed in X. citri subsp. citri ( 62 ) and X. oryzae pv oryzae ( 42 ). Wang et al ( 42 ) named the genes bfeA , bfeA2 , and bfeA3 and reported that mutating bfeA alone ended up in a reduced-virulence phenotype in planta .…”

The prevalence ofFusobacterium nucleatumsubspecies in the oral cavity stratifies by local health status

“…animalis, we identified several gene clusters that are highly characteristic of this organism, the most prominent of which encodes the high affinity ferrous iron transport system FeoA/B. Orthologs of the FeoAB transporter are crucial for virulence in a variety of organisms, including the oral pathobiont P. gingivalis (27,28) as well as other heavily studied animal and plant pathogens like Salmonella enterica, Helicobacter pylori, and Xanthomonas species (29)(30)(31)(32). It is conceivable that in addition to the core collection of irontransport genes encoded by oral fusobacteria (Table S8), the additional high affinity FeoAB iron transporter could provide a specific growth advantage to Fn.…”