Natalia Malfanova

Publications (3)5.4 Total impact

• Article: Is L-arabinose important for the endophytic lifestyle of Pseudomonas spp.?

  Natalia Malfanova, Faina Kamilova, Shamil Validov, Vladimir Chebotar, Ben Lugtenberg
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  ABSTRACT: Twenty endophytic bacteria were isolated from surface-sterilized stems and roots of cucumber plants. After removal of potential siblings and human pathogens, the remaining seven strains were identified based on their 16S rDNA as Pseudomonas fluorescens (2 strains) and P. putida (5 strains). Three strains, namely P. fluorescens CS1, P. fluorescens CR2 and P. putida CR3, were able to suppress tomato foot and root rot (TFRR). Special attention was paid to the characterization of the BIOLOG carbon oxidation profiles of the isolated pseudomonads in order to identify nutrients which might be important for their endophytic lifestyle. Comparative analysis of the profiles of these seven strains with those of seven rhizospheric Pseudomonas spp. revealed that endophytes were able to oxidize L-arabinose and 2,3-butanediol significantly more often than the rhizospheric group. An independent growth experiment performed in tubes using L-arabinose and 2,3-butanediol as sole carbon sources showed the same results as seen using BIOLOG for L-arabinose, but not for 2,3-butanediol. Since L-arabinose is one of the most abundant sugars in xylem of cucumber plants and was not detected in their rhizosphere, our data suggest that utilization of L-arabinose might be a trait contributing to the endophytic lifestyle of the isolated Pseudomonas endophytes.
  Archives of Microbiology 09/2012; · 1.43 Impact Factor
• Source

  Available from: Ben Lugtenberg

  Article: Cyclic lipopeptide profile of the plant-beneficial endophytic bacterium Bacillus subtilis HC8.

  Natalia Malfanova, Laurent Franzil, Ben Lugtenberg, Vladimir Chebotar, Marc Ongena
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  ABSTRACT: In a previous study (Malfanova et al. in Microbial Biotech 4:523-532, 2011), we described the isolation and partial characterization of the biocontrol endophytic bacterium B. subtilis HC8. Using thin-layer chromatography, we have detected several bioactive antifungal compounds in the methanolic extract from the acid-precipitated supernatant of HC8. In the present study, we have further analyzed this methanolic extract using liquid chromatography-mass spectrometry. Based on the comparison of retention times and molecular masses with those of known antifungal compounds, we identified three families of lipopeptide antibiotics. These include four iturins A having fatty acyl chain lengths of C14 to C17, eight fengycins A (from C14 to C18 and from C15 to C17 containing a double bond in the acyl chain), four fengycins B (C15 to C18), and five surfactins (C12 to C16). Evaluation of the antifungal activity of the isolated lipopeptides showed that fengycins are the most active ones. To our knowledge, this is the first report of an endophytic Bacillus subtilis producing all three major families of lipopeptide antibiotics containing a very heterogeneous mixture of homologues. The questions remain open which of these lipopeptides (1) are being produced during interaction with the plant and (2) are contributing to the biocontrol activity of HC8.
  Archives of Microbiology 05/2012; 194(11):893-9. · 1.43 Impact Factor
• Source

  Available from: Faina Kamilova

  Article: Characterization of Bacillus subtilis HC8, a novel plant-beneficial endophytic strain from giant hogweed.

  Natalia Malfanova, Faina Kamilova, Shamil Validov, Andrey Shcherbakov, Vladimir Chebotar, Igor Tikhonovich, Ben Lugtenberg
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  ABSTRACT: Thirty endophytic bacteria were isolated from various plant species growing near Saint-Petersburg, Russia. Based on a screening for various traits, including plant-beneficial properties and DNA fragment patterns, potential siblings were removed. The remaining isolates were taxonomically identified using 16S rDNA sequences and potential human and plant pathogens were removed. The remaining strains were tested for their ability to promote radish root growth and to protect tomato plants against tomato foot and root rot. One strain, Bacillus subtilis HC8, isolated from the giant hogweed Heracleum sosnowskyi Manden, significantly promoted plant growth and protected tomato against tomato foot and root rot. Metabolites possibly responsible for these plant-beneficial properties were identified as the hormone gibberellin and (lipo)peptide antibiotics respectively. The antibiotic properties of strain HC8 are similar to those of the commercially available plant-beneficial strain Bacillus amyloliquefaciens FZB42. However, thin layer chromatography profiles of the two strains differ. It is speculated that endophytes such as B. subtilis HC8 contribute to the fast growth of giant hogweed.
  Microbial Biotechnology 03/2011; 4(4):523-32. · 2.53 Impact Factor