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Xanthomonas campestris diffusible factor is 3-hydroxybenzoic acid and is associated with xanthomonadin biosynthesis, cell viability, antioxidant activity, and systemic invasion

Institute of Molecular and Cell Biology, Singapore.
Molecular Plant-Microbe Interactions (Impact Factor: 4.46). 05/2011; 24(8):948-57. DOI: 10.1094/MPMI-02-11-0031
Source: PubMed

ABSTRACT Xanthomonas campestris pv. campestris produces a membrane-bound yellow pigment called xanthomonadin. A diffusible factor (DF) has been reported to regulate xanthomonadin biosynthesis. In this study, DF was purified from bacterial culture supernatants using a combination of solvent extraction, flash chromatography, and high-performance liquid chromatography. Mass spectrometry and nuclear magnetic resonance analyses resolved the DF chemical structure as 3-hydroxybenzoic acid (3-HBA), which was further confirmed by synthetic 3-HBA. Significantly, bioassay and in silico analysis suggest that DF production is widely conserved in a range of bacterial species. Analysis of DF derivatives established the hydroxyl group and its position as the key structural features for the role of DF in xanthomonadin biosynthesis. In addition, we showed that DF is also associated with bacterial survival, H2O2 resistance, and systemic invasion. Furthermore, evidence was also presented that DF and diffusible signaling factor have overlapping functions in modulation of bacterial survival, H2O2 resistance, and virulence. Utilization of different mechanisms to modulate similar virulence traits may provide X. campestris pv. campestris with plasticity in response to various environmental cues.

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    • "This disease, even with all the damages caused in the Volumen 31 Número 2, 2013 147 REVISTA MEXICANA DE FITOPATOLOGÍA al., 2009). Las colonias bacterianas crecidas en medio artificial son usualmente amarillas debido a la presencia de p i g m e n t o e n l a s m e m b r a n a s c o n o c i d o c o m o xanthomonadina, el cual las protege del daño oxidativo (He et al., 2011). Dentro de este género, la especie X. axonopodis afecta a un amplio rango de hospedantes, encontrándose especies cultivadas de importancia económica (Hayward, 1993), entre ellos el frijol (Phaseolus vulgaris) ocasionando la enfermedad del tizón común bacteriano causado por el patovar phaseoli. "
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    • "This disease, even with all the damages caused in the Volumen 31 Número 2, 2013 147 REVISTA MEXICANA DE FITOPATOLOGÍA al., 2009). Las colonias bacterianas crecidas en medio artificial son usualmente amarillas debido a la presencia de p i g m e n t o e n l a s m e m b r a n a s c o n o c i d o c o m o xanthomonadina, el cual las protege del daño oxidativo (He et al., 2011). Dentro de este género, la especie X. axonopodis afecta a un amplio rango de hospedantes, encontrándose especies cultivadas de importancia económica (Hayward, 1993), entre ellos el frijol (Phaseolus vulgaris) ocasionando la enfermedad del tizón común bacteriano causado por el patovar phaseoli. "
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    ABSTRACT: Resumen. Xanthomonas axonopodis pv. phaseoli (Xap) (Smith) es la bacteria que ocasiona el tizón común bacteriano del frijol (Phaseolus vulgaris L.) síntoma que se caracteriza por la aparición de manchas con aspecto de tizón con un halo amarillo en hojas, tallos, y frutos reduciendo así el rendimiento del cultivo. La taxonomía de este patógeno ha sido muy cambiante debido a su variabilidad genética. La semilla infectada es la forma más eficiente de dispersión de la enfermedad entre las áreas cultivadas, el éxito de la infección y la multiplicación bacteriana en el tejido hospedero frecuentemente depende de factores de virulencia y del sistema de secreción. Los métodos de manejo que se emplean para contrarrestar la enfermedad en campo no han sido efectivos, no obstante, la constante búsqueda de nuevos enfoques como el empleo de agentes de biocontrol e inductores de resistencia, abren nuevas expectativas para su control. Abstract. Xanthomonas axonopodis pv. Phaseoli (Xap) (Smith) is the bacterium that causes common bacterial blight in bean plants (Phaseolus vulgaris L.) characterized by irregular necrotic staining with yellow halo on leaves, stems, and fruits with crop yield reduction. The taxonomy of this pathogen has been changing due their genetic variability. Infected seeds are one of the most efficient forms of disease dispersal between cultivated areas, the infection and bacterial multiplication in the host tissue often depend on the virulence factors and their secretion system. Management methods that are used to counter the disease in the field have not been effective, however, the constant search for new approaches as the use of biocontrol agents and resistance inducers, open new prospects for control.
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    • "Bacterial supernatants (30 liters) were collected by centrifugation (3,800 rpm for 30 min at 4°C). 3-HBA and 4- HBA were extracted and purified following a previously described method (He et al. 2011; Zhou et al. 2013). "
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    ABSTRACT: Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of rice bacterial blight, produces membrane-bound yellow pigments, referred to as xanthomonadins. Xanthomonadins protect the pathogen from photodamage and host-induced perioxidation damage. They are also required for epiphytic survival and successful host plant infection. Here, we show that XanB2 encoded by PXO_3739 plays a key role in xanthomonadin and coenzyme Q8 biosynthesis in Xoo strain PXO99A. A xanB2 deletion mutant exhibits a pleiotropic phenotype, including xanthomonadin deficiency, producing less exopolysaccharide (EPS), lower viability and H2O2 resistance, and lower virulence. We further demonstrate that Xoo produces 3-hydroxybenzoic acid (3-HBA) and 4-hydroxybenzoic acid (4-HBA) via XanB2. 3-HBA is associated with xanthomonadin biosynthesis while 4-HBA is mainly used as a precursor for CoQ8 biosynthesis. XanB2 is the alternative source of 4-HBA for CoQ8 biosynthesis in PXO99A. These findings suggest that the roles of XanB2 in PXO99A are generally consistent with those in Xcc. The present study also demonstrated that Xoo strain PXO99A has evolved several specific features in 3-HBA and 4-HBA signaling. First, our results showed that PXO99A produces less 3-HBA and 4-HBA than Xcc and this is partially due to a degenerated 4-HBA efflux pump. Second, PXO99A has evolved unique xanthomonadin induction patterns via 3-HBA/4-HBA. Third, our results showed that 3-HBA or 4-HBA positively regulates the expression of gum cluster to promote EPS production in PXO99A. Taken together, the results of this study indicate that XanB2 is a key metabolic enzyme linking xanthomonadin, CoQ and EPS biosynthesis, which are collectively essential for Xoo pathogenesis.
    Molecular Plant-Microbe Interactions 05/2013; 26(10). DOI:10.1094/MPMI-04-13-0112-R · 4.46 Impact Factor
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