Diversidad y control biológico de insectos - CyberTesis UACh ...

sample, showing the potential use of this nuclear fragment for strain fingerprinting. A
eleven sub-sample, representing the major clades, was additionally analized by sequencing
the elongation factor 1 alpha (EF1-α) gene. The resulting EF1-α topology mostly agreed
with the B locus topology and allowed to analyze the genetic diversity of the fungus in
Chile under current phylogenetic hypotheses for the B. bassiana complex, which suggest
the existence of cryptic species into what is morphologically defined as B. bassiana.
Keywords: entomopathogenic fungus; biological control; population structure; elongation
factor 1 alpha.
Introduction.
The haploid filamentous fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota:
Hypocreales) is a common soil inhabiting organism, consuming organic matter
(saprophytic stage) and/or infecting arthropods (parasitic stage). Its pathogenic properties
have been long recognized and have attracted much effort to use this fungus as a biological
control agent against many agricultural, medical and veterinary important pests. Several
biological control programmes based on this fungus have successed in recent years, but in
other cases more erratic results have been obtained. Some of these failures could have been
explained and overcome if a better understanding of life traits, ecological interactions and
phylogenetic constraints were available.
The efforts directed to understand the above mentioned issues are limited by the lack of
enough reliable phenotypic characters to discriminate among species into the genus and
among strains into the species. The genus Beauveria harbours several species defined
mostly by the conidia morphology, while strain identity at infra-species level is even more
unclear if morphology is the only criteria.
The species and strain identity is an integral part of any environmental risk and efficacy
assessment structure. In consequence, biochemical and molecular tools have been used to
fingerprint strains of particular interest. The mitochondrial DNA has been the preferred
target of infra-species studies because of its faster evolution rate, but recently the nuclear
DNA has arose as another valid alternative. Nuclear genes are suitable for intraspecific
studies as they serve as nonlinked genetic markers, converse to mitochondrial genes which
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