Abstract

ROSAS-GARCIA, Ninfa M.; MIRELES-MARTINEZ, Maribel  and  VILLEGAS-MENDOZA, Jesús Manuel. Bassianolide and beauvericin detection in Beauveria bassiana strains and their participation in the pathogenic activity against Spodoptera sp.. Biotecnia [online]. 2020, vol.22, n.3, pp.93-99.  Epub Feb 10, 2021. ISSN 1665-1456.  https://doi.org/10.18633/biotecnia.v22i3.1060.

Beauveria bassiana is an entomopathogenic fungus that produces secondary metabolites as virulence factors during the pathogenic process in insects. In this study, eleven strains of B. bassiana were analyzed to determine the presence of the bbBeas and bbBsls genes that produce beauvericin and bassianolide non-ribosomal cyclooligomeric depsypeptides, respectively. The genes were characterized by PCR and DNA sequencing. The presence of beauvericin and bassianolide from mycelial extracts were determined by mass spectrometry. The results indicated that with the exception of strain 2857, they all possess both genes and synthesized bassianolide. Beauvericin was not produced in any case. Mortality caused by conidia in Spodoptera exigua and S. frugiperda neonate larvae was variable. Strains 1512, 2253 and 2857 caused significantly higher mortalities (44 % mortality on average). The bassianolide extract injected (1 mg/mL) caused 26 % mortality in S. exigua. The lack of beauvericin production, with the exception of strain 1149, may be due to the requirement of other culture conditions that stimulate the expression of the genes. So far, no correlation is observed between the pathogenic activity of the fungus, and the presence or absence of these secondary metabolites.

Keywords : Bioactive peptides; Secondary metabolite; Entomopathogen; Insect pest.

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