Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

Baptista, Juliana Cristina; Machado, Marcos Antônio; Homem, Rafael A.; Torres, Pablo; Vojnov, Adrián Alberto; Amaral, Alexandre Morais do

doi:10.1590/s1415-47572009005000110

Cited by 25 publications

(20 citation statements)

References 27 publications

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“…The medium was 0.5 % carboxymethylcellulose, 0.1 % NaNO 3 , 0.1 % K 2 HPO 4 , 0.1 % KCl, 0.05 % MgSO 4 , 0.05 % yeast extract, 0.1 % glucose and 1.7 % agar [32]. The revelation was done by pouring 0.1 % red Congo solution onto the plates, followed by washing with 1 M NaCl.…”

Section: Cellulase Activitymentioning

confidence: 99%

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii

et al. 2015

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Four strains of Hortaea werneckii were isolated from different substrates in Brazil (a salt marsh macrophyte, a bromeliad and a marine zoanthid) and had their identification confirmed by sequencing of the 26S rDNA D1/D2 domain or ITS region. Most of the strains were able to express amylase, lipase, esterase, pectinase and/or cellulase, enzymes that recognize components of plant cells as substrates, but did not express albuminase, keratinase, phospholipase and DNAse, whose substrates are animal-related. Urease production was positive for all isolates, while caseinase, gelatinase and laccase production were variable among the strains. All the strains grew in media containing up to 30% NaCl. We propose that the primary substrate associated with H. werneckii is plant-related, in special in saline environments, where the fungus may live as a saprophyte and decomposer. Infection of animal-associated substrates would be secondary, with the fungus acting as an opportunistic animal pathogen. All strains were resistant to fluconazole and presented high MIC for amphotericin B, while they were susceptible to all the other antifungal agents tested.

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Section: Cellulase Activitymentioning

confidence: 99%

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii

et al. 2015

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“…In Xcc, it has been demonstrated that extracellular enzymes contribute to canker symptom development by degrading the epidermal cell wall. Different kinds of protein are secreted via the T2SS, including protease, amylase and cellulase (Baptista et al, 2010). Two mutants were found to contain the transposon insertion in the XAC3534/ xpsD and in the XAC0695/xcsD genes.…”

Section: Biofilm-defective Mutant Affected In Chemotaxismentioning

confidence: 99%

Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri

et al. 2013

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Xanthomonas citri subsp. citri (Xcc) develops a biofilm structure both in vitro and in vivo. Despite all the progress achieved by studies regarding biofilm formation, many of its mechanisms remain poorly understood. This work focuses on the identification of new genes involved in biofilm formation and how they are related to motility, virulence and chemotaxis in Xcc. A Tn5 library of approximately 6000 Xcc (strain 306) mutants was generated and screened to search for biofilm formation defective strains. We identified 23 genes not previously associated with biofilm formation. The analysis of the 23 mutants not only revealed the involvement of new genes in biofilm formation, but also reinforced the importance of exopolysaccharide production, motility and cell surface structures in this process. This collection of biofilm-defective mutants underscores the multifactorial genetic programme underlying the establishment of biofilm in Xcc.

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“…Interestingly, we found that in addition to the TonB system, the entire Xps type II secretion cluster was recombinant among the pepper pathogenic strains of SC3. The importance of the Xps type II gene cluster in the secretion of numerous plant-cell wall degrading enzymes and virulence has been well established in Xeu (36–38). Therefore, it is possible that the recombination-mediated remodeling of the TonB and Xps type II systems may affect the secretion of plant cell-wall degrading enzymes and the regulation of downstream pathogenesis processes, leading to adaptation within the pepper niche.…”

Section: Discussionmentioning

confidence: 99%

Recently emerged and diverse lineages of Xanthomonas perforans have independently evolved through plasmid acquisition and homologous recombination originating from multiple Xanthomonas species

Newberry

Bhandari

Minsavage

et al. 2019

Preprint

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0Xanthomonas perforans is the predominant pathogen responsible for bacterial leaf spot of tomato 1 1 and X. euvesicatoria of pepper in the southeast United States. Previous studies have indicated 1 2 significant changes in the X. perforans population collected from Florida tomato fields over the 1 3 span of two decades including a shift in race, diversification into three genetic groups, and host 1 4 range expansion to pepper. Recombination originating from X. euvesicatoria was identified as 1 5 the primary factor driving the diversification of X. perforans in Florida. The aim of this study 1 6 was to genetically characterize X. perforans strains that were isolated from tomato and pepper 1 7 plants grown in Alabama and compare them to the previously published genomes available from 1 8GenBank. Surprisingly, a maximum likelihood phylogeny coupled with a Bayesian analysis of 1 9 population structure revealed the presence of two novel genetic groups in Alabama, which each 2 0 harbored a different transcription activation-like effector (TALE). While one TALE, avrHah1, 2 1 2 was associated with adaptation of X. perforans to pepper, the other was identified as a new class 2 2 within the avrBs3 family, designated here as pthXp1. Examination of patterns of homologous 2 3 recombination between X. perforans and other closely related Xanthomonas spp. indicated that 2 4 the lineages identified here emerged in part through recent recombination events originating 2 5 from xanthomonads associated with diverse hosts of isolation. Our results also suggest that the 2 6 evolution of pathogenicity to pepper has likely emerged independently within X. perforans and 2 7 in one lineage, was associated with the recombination-mediated remodeling of the Xps type II 2 8 secretion and TonB transduction systems. 2 9 Importance 3 0The emergence of novel pathogen lineages has important implications in the sustainability of 3 1 genetic resistance as a disease management tool in agricultural ecosystems. In this study, we 3 2 identified two novel lineages of X. perforans in Alabama. While one lineage was isolated from 3 3 symptomatic pepper plants, confirming the host range expansion of X. perforans, the other 3 4 lineage was isolated from tomato and acquired a novel transcription activation-like effector, 3 5 pthXp1. Unlike AvrBs4, PthXp1overcomes Bs4-mediated resistance in tomato, indicating the 3 6 evolution of this novel lineage towards fitness on this host. Our findings also show that different 3 7 phylogenetic groups of the pathogen have experienced independent recombination events 3 8 originating from multiple Xanthomonas species. This suggests a continuous gene flux between 3 9 related xanthomonads associated with diverse plant hosts which results in the emergence of 4 0 novel pathogen lineages and associated phenotypes, including host range expansion.4 1

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Mutation in the xpsD gene of Xanthomonas axonopodis pv. citri affects cellulose degradation and virulence

Cited by 25 publications

References 27 publications

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii

Enzymatic Activity and Susceptibility to Antifungal Agents of Brazilian Environmental Isolates of Hortaea werneckii

Identification and characterization of biofilm formation-defective mutants of Xanthomonas citri subsp. citri

Recently emerged and diverse lineages of Xanthomonas perforans have independently evolved through plasmid acquisition and homologous recombination originating from multiple Xanthomonas species

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