Detection of acylhomoserine lactones in cultures of Gluconacetobacter diazotrophicus PAL5

NIETO PEÑALVER CG; BICHARA L; MARINO D; CASTELLANOS DE FIGUEROA LI; IRAZUSTA V

Puerto Madryn

Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Gluconacetobacter diazotrophicus is an acid-tolerant nitrogenfixingAlphaproteobacterium first found in association withsugarcane. It has also been isolated from rice, coffee and tea, amongothers crops. The recent sequencing of the G. diazotrophicus PAL5genome shows the presence of one luxI homolog. These genesencode LuxI-type enzymes responsible for the synthesis of Nacylhomoserinelactones (AHLs), the main quorum sensingmolecules in gram negative bacteria. The objective of this work wasthe detection and identification of AHLs produced by G.diazotrophicus PAL5. The strain was cultured aerobically, andextracts were prepared with acidified ethyl acetate. Samples wereanalyzed by thin layer chromatography developed with thebiosensor Agrobacterium tumefaciens NTL4 (pCF218) (pCF372).Results show that G. diazotrophicus PAL5 produce at least two typesof AHLs under the assayed conditions. Short-chain AHLs could bedetected since early exponential growth phase, and medium-chainAHLs were detected in mid- and late-exponential growth phase. Theresults suggest that the luxI homolog in G. diazotrophicus PAL5 isexpressed and quorum sensing molecules are produced andsecreted. Similar to other bacteria, production of AHLs in G.diazotrophicus PAL5 could serves as a signaling mechanism amongmembers of this genus or as inter kingdom signals.