Bioactive secondary metabolites and hydrolytic enzymes produced by strains of Burkholderia gladioli pv. gladioli

Lamorte D., P. Lo Cantore and N. S. Iacobellis Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, 2Dipartimento di Scienze, Università degli Studi della Basilicata, Viale dell’Ateneo Lucano 10, 85100, Potenza, Italy; E-mail: nicola.iacobellis@unibas.it The genus Burkholderia include more than 40 validly described species associated to plants and animal with beneficial or detrimental features in the occupied niches. Some beneficial Burkholderia species are potentially exploitable in biotechnological and agricultural industry or for bioremediation of recalcitrant xenobiotic but unfortunately the fact that some members of the genus have been involved in human infections is hampering their exploitation. B. gladioli, initially described as a phytopathogenic species, contains the pathovars gladioli, allicola and agaricicola which causes gladiolus and onion bulb rot, and soft rot of cultivated mushrooms, respectively. Recently, the new pathovar cocovenenans primarily associated to toxicity of food processed from plants commodities, apparently due to the highly toxic compounds toxoflavin and Bongkrekic acid, has been described. Unlike B. g. pv. agaricicola whose ability to produce antimicrobial secondary metabolites and hydrolytic enzymes as well as the QS regulation of their production and potential role in the pathogen virulence has been recently determined, no information in this regard are available for B. g. pv. gladioli. In this study the production of antimicrobial metabolites in dual plate assays as well as hydrolytic enzymes by representative strains of B. g. pv. gladioli has been ascertained. Liquid culture extracts of virulent strains of B. g. pv. gladioli showed antimicrobial and haemolytic activities. HPLC analyses of bioactive culture extracts gave rise to individual fractions whose chemical and biological characterization has been determined.