Cytotoxic Activity of Fungal Metabolites from the Pathogenic Fungus Beauveria bassiana: An Intraspecific Evaluation of Beauvericin Production Jorge W. Arboleda Valencia • Alvaro L. Gaita ´n Bustamante • Arnubio Valencia Jime ´nez • Ma Fa ´tima Grossi-de-Sa ´ Received: 5 May 2011 / Accepted: 29 June 2011 / Published online: 15 July 2011 Ó Springer Science+Business Media, LLC 2011 Abstract The cyclohexadepsipeptide beauvericin (BEA) is a mycotoxin produced by the fungus Beauveria bassiana (Bals.). Using ELISA, different accessions of B. bassiana, belonging to distinct genetic groups, were analyzed to determine their variability in BEA production. The cyto- toxic effect of pure mycotoxins and crude extracts was also tested on insect cell lines SF-9 and SF-21. The results showed that BEA production was significantly different between all strains. Bb 9024 exhibited the highest levels (98.56 mg/l), while Bb 9001 the lowest (15.66 mg/l). Statistical difference was found when BEA CC 50 values (2.81 and 6.94 lM) were compared with those values from others mycotoxins (4.23–11.95 lM). Although no corre- lation has been observed between beauvericin production and phylogenetic grouping, the results suggest a compre- hensible involvement of these metabolites during the infection process. The biological evaluation of metabolites produce by entomopathogenic fungi provides better criteria to design more effective formulations for pest management. Introduction The genetic diversity of entomopathogenic populations represents an alternative in order to explore valuable microorganisms with better efficiency of insect control at field conditions [24]. A former molecular characterization of variability in 95 B. bassiana strains indicated a low but significant degree of genetic diversity, which is not linked to geographic distribution [8]. In addition to some viru- lence tests, genes and metabolites of interest have been also screened to design new formulations that combine multiple mechanisms used by the fungus during the infection pro- cess. These mechanisms include the production of sec- ondary metabolites such as the mycotoxins BEA, tenellin, bassianin, beauveriolide, oosporein and the recently described bassiacridin [18]. Mycotoxins are relatively small molecules that play an important role in fungal infection and can generate a toxic response in different organisms [22]. The ability of B. bassiana to overcome host defenses and eliminate bacterial competition has been demonstrated to be due in great part to toxin production [19]. The mycotoxin beauvericin was first discovered in B. bassiana [12]. It is a cyclohexadepsipeptide, consisting of three N-methyl phenylalanine molecules alternated with three hydroxyisovalerate acid molecules. The mycotoxin can be produced by other species of the genus Beauveria, such as Beauveria brongniartii, and by other genera [9]. Although these entomopathogens may display similar biological actions on the host insects, studies indicate that the complex profile of mycotoxin production in Beauveria J. W. A. Valencia Á A. L. Gaita ´n Bustamante Centro Nacional de Investigaciones de Cafe ´, CENICAFE-FEDERACAFE, Disciplina de Fitopatologia, Planalto Km 4 Via a Manizales, Chinchina ´, Caldas, Colombia J. W. A. Valencia Departamento de Biologia Celular, Universidade de Brası ´lia, Asa Norte, Brası ´lia, DF 70910-900, Brazil J. W. A. Valencia (&) Á M. F. Grossi-de-Sa ´ Embrapa Recursos Gene ´ticos e Biotecnologia, PqEB Final W5 Norte, CP 02372, Asa Norte, Brası ´lia, DF 70770-900, Brazil e-mail: jwarboleda@gmail.com A. V. Jime ´nez Grupo de Investigaciones Pla ´tano, Departamento de Fitotecnia, Facultad de Ciencias Agropecuarias, Universidad de Caldas, Calle 65 # 26-10, Manizales, Caldas, Colombia 123 Curr Microbiol (2011) 63:306–312 DOI 10.1007/s00284-011-9977-2