High genetic diversity of the entomopathogenic fungus Beauveria bassiana in Colima, Mexico

[Display omitted] •A biocontrol agent requires correct identification and genetic diversity knowledge.•22 Beauveria bassiana isolates were placed in AFNEO_1 clade with a high variation.•High genotypic nucleotide variation was revealed by sequence analysis of TEF and Bloc loci.•SSR markers resolved 40 genotypes from 43 isolates identified as B. bassiana.•No association of B. bassiana with substrate, insect-host or municipality was found. The entomopathogenic fungus Beauveria bassiana is used widely as a biological control agent against a wide range of insect pests globally. In this study, 44 Beauveria isolates from the state of Colima, Mexico harbored in the “Colección de Hongos Entomopatógenos” of the “Centro Nacional de Referencia de Control Biológico” and from different substrates, insect-hosts, and localities were characterized with molecular markers. All isolates were identified using a Bayesian phylogenetic analysis of translation elongation factor 1-α (TEF) and nuclear intergenic Bloc region. Forty-three isolates were identified as B. bassiana and grouped into two sub-clades, i.e., AFNEO_1 (n = 22; previously defined as a clade with African and Neotropical origin) and Bb clade (n = 21; closely associated with ex-type strain ARSEF 1564), and one isolate was identified as B. pseudobassiana. The fixation index (FST = 0.493) established the genetic differentiation between AFNEO_1 and Bb clades. High genotype richness and genetic diversity of AFNEO_1 and Bb clades were revealed in sequence analysis of Bloc region and SSR genotyping. Moreover, the AFNEO_1 and Bb clades were confirmed as two independent clonally structured assemblages. Finally, the AMOVA detected no significant association between any combination of substrate, insect-host or geographical origin. High genetic variation of B. bassiana in Colima, Mexico could suggest a functional diversity among isolates that may include those effective against a specific insect pest.