Valter A De Baura

Publications (3)12.29 Total impact

• Article: The type III secretion system is necessary for the development of a pathogenic and endophytic interaction between Herbaspirillum rubrisubalbicans and Poaceae.

  Maria A Schmidt, Eduardo Balsanelli, Helisson Faoro, Leonardo M Cruz, Roseli Wassem, Valter A de Baura, Vinicius Weiss, Marshall G Yates, Humberto M F Madeira, Lilian Pereira-Ferrari, Maria H P Fungaro, Francine M de Paula, Luiz F P Pereira, Luiz G E Vieira, Fábio L Olivares, Fábio O Pedrosa, Emanuel M de Souza, Rose A Monteiro
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  ABSTRACT: BACKGROUND: Herbaspirillum rubrisubalbicans was first identified as a bacterial plant pathogen, causing the mottled stripe disease in sugarcane. H. rubrisubalbicans can also associate with various plants of economic interest in a non pathogenic manner. RESULTS: A 21 kb DNA region of the H. rubrisubalbicans genome contains a cluster of 26 hrp/hrc genes encoding for the type three secretion system (T3SS) proteins. To investigate the contribution of T3SS to the plant-bacterial interaction process we generated mutant strains of H. rubrisubalbicans M1 carrying a Tn5 insertion in both the hrcN and hrpE genes. H. rubrisulbalbicans hrpE and hrcN mutant strains of the T3SS system failed to cause the mottled stripe disease in the sugarcane susceptible variety B-4362. These mutant strains also did not produce lesions on Vigna unguiculata leaves. Oryza sativa and Zea mays colonization experiments showed that mutations in hrpE and hrcN genes reduced the capacity of H. rubrisulbalbicans to colonize these plants, suggesting that hrpE and hrcN genes are involved in the endophytic colonization. CONCLUSIONS: Our results indicate that the T3SS of H. rubrisubalbicans is necessary for the development of the mottled stripe disease and endophytic colonization of rice.
  BMC Microbiology 06/2012; 12(1):98. · 3.04 Impact Factor
• Article: Genomic comparison of the endophyte Herbaspirillum seropedicae SmR1 and the phytopathogen Herbaspirillum rubrisubalbicans M1 by suppressive subtractive hybridization and partial genome sequencing.

  Rose A Monteiro, Eduardo Balsanelli, Thalita Tuleski, Helison Faoro, Leonardo M Cruz, Roseli Wassem, Valter A de Baura, Michelle Z Tadra-Sfeir, Vinícius Weiss, Wanderson D DaRocha, Marcelo Muller-Santos, Leda S Chubatsu, Luciano F Huergo, Fábio O Pedrosa, Emanuel M de Souza
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  ABSTRACT: Herbaspirillum rubrisubalbicans M1 causes the mottled stripe disease in sugarcane cv. B-4362. Inoculation of this cultivar with Herbaspirillum seropedicae SmR1 does not produce disease symptoms. A comparison of the genomic sequences of these closely related species may permit a better understanding of contrasting phenotype such as endophytic association and pathogenic life style. To achieve this goal, we constructed suppressive subtractive hybridization (SSH) libraries to identify DNA fragments present in one species and absent in the other. In a parallel approach, partial genomic sequence from H. rubrisubalbicans M1 was directly compared in silico with the H. seropedicae SmR1 genome. The genomic differences between the two organisms revealed by SSH suggested that lipopolysaccharide and adhesins are potential molecular factors involved in the different phenotypic behavior. The cluster wss probably involved in cellulose biosynthesis was found in H. rubrisubalbicans M1. Expression of this gene cluster was increased in H. rubrisubalbicans M1 cells attached to the surface of maize root, and knockout of wssD gene led to decrease in maize root surface attachment and endophytic colonization. The production of cellulose could be responsible for the maize attachment pattern of H. rubrisubalbicans M1 that is capable of outcompeting H. seropedicae SmR1.
  FEMS Microbiology Ecology 01/2012; 80(2):441-51. · 3.41 Impact Factor
• Article: Herbaspirillum seropedicae rfbB and rfbC genes are required for maize colonization.

  Eduardo Balsanelli, Rodrigo V Serrato, Valter A de Baura, Guilherme Sassaki, Marshall G Yates, Liu Un Rigo, Fábio O Pedrosa, Emanuel M de Souza, Rose A Monteiro
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  ABSTRACT: In this study we disrupted two Herbaspirillum seropedicae genes, rfbB and rfbC, responsible for rhamnose biosynthesis and its incoporation into LPS. GC-MS analysis of the H. seropedicae wild-type strain LPS oligosaccharide chain showed that rhamnose, glucose and N-acetyl glucosamine are the predominant monosaccharides, whereas rhamnose and N-acetyl glucosamine were not found in the rfbB and rfbC strains. The electrophoretic pattern of the mutants LPS was drastically altered when compared with the wild type. Knockout of rfbB or rfbC increased the sensitivity towards SDS, polymyxin B sulfate and salicylic acid. The mutants attachment capacity to maize root surface plantlets was 100-fold lower than the wild type. Interestingly, the wild-type capacity to attach to maize roots was reduced to a level similar to that of the mutants when the assay was performed in the presence of isolated wild-type LPS, glucosamine or N-acetyl glucosamine. The mutant strains were also significantly less efficient in endophytic colonization of maize. Expression analysis indicated that the rfbB gene is upregulated by naringenin, apigenin and CaCl(2). Together, the results suggest that intact LPS is required for H. seropedicae attachment to maize root and internal colonization of plant tissues.
  Environmental Microbiology 08/2010; 12(8):2233-44. · 5.84 Impact Factor