Identification and characterization of a long-chain 饾槙-acyl homoserine lactone from 饾槞饾槱饾槳饾樆饾槹饾槪饾槳饾樁饾槷 sp. isolated from 饾槨饾槮饾槩 饾樄 饾槷饾槩饾樅饾槾 rhizosphere

Abstract

The microbiological study of maize rhizosphere (饾槨饾槮饾槩 饾樄 饾槷饾槩饾樅饾槾) cultivated in Brazil led to the isolation of a bacterium, which was identified as 饾槞饾槱饾槳饾樆饾槹饾槪饾槳饾樁饾槷 sp. based upon 16 S rRNA analysis. The chemical study of fractions obtained from bacterium extract allowed the identification of the compound N-(3-oxo-tetradec-7-enoyl)- homoserine lactone using uni and bidimensional nuclear magnetic resonance spectroscopy (NMR), gas chromatography coupled to low resolution electron impact mass spectrometry (GC鈥揗S), and ultra-high re solution Qq-time-of-flight mass spectrometry (UHR-QqTOF-MS). Biological assays with the strains 饾槇饾槰饾槼饾槹饾槪饾槩饾槫饾樀饾槮饾槼饾槳饾樁饾槷 饾樀饾樁饾槷饾槮饾槯饾槩饾槾饾槫饾槳饾槮饾槸饾槾 A136 and 饾槉饾槱饾槼饾槹饾槷饾槹饾槪饾槩饾槫饾樀饾槮饾槼饾槳饾樁饾槷 饾樂饾槳饾槹饾槶饾槩饾槫饾槮饾樁饾槷 CV026 were also performed and showed negative results, corroborating the hypothesis of production of only the long chain acyl homoserine lactone (AHL) 1, and the lack of presence of short or medium chain homologues, as observed by instrumental GC鈥揗S and NMR analyses. The chemotaxonomic relevance of the presence of long chain AHL in Rhizobiaceae was discussed.