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Updated: Jul 7, 2026
Isolation, Behavioral Identification, and Pathogenicity Assessment of Entomopathogenic Fungi from a Forest Wood Borer
Published on: September 29, 2023
Microsatellite variability in the entomopathogenic fungus Paecilomyces fumosoroseus: genetic diversity and population
Nathalie Gauthier1, Cécile Dalleau-Clouet, Jacques Fargues
1Centre de Biologie et de Gestion des Populations, Institut de Recherche pour le Développement, Campus International de Baillarguet, CS30016, 34988 Montferrier sur lez, France. nathalie.gauthier@supagro.inra.fr
Abstract:
The hyphomycete Paecilomyces fumosoroseus (Pfr) is a geographically widespread fungus capable of infecting various insect hosts. The fungus has been used for the biological control of several important insect pests of agriculture. However knowledge of the fungus' genetic diversity and population structure is required for its sustainable use as a biological control agent. We investigated length and sequence polymorphisms of nine microsatellite loci for 33 Pfr accessions sampled from various host species and geographical locations, and our results reveal complex mutational processes for these molecular markers. Only Pfr isolates from Bemisia tabaci were amplified successfully, indicating the existence of Pfr genotypes specifically associated with B. tabaci. Genetic relationships among the 25 Pfr isolates from B. tabaci were inferred from allelic variability data at eight microsatellite loci that were polymorphic and subsequently from sequence data from the flanking regions of three selected loci. Maximum parsimony and neighbor joining analyses partitioned Pfr genetic diversity in two major lineages. One lineage included genotypes from the B-biotype of B. tabaci distributed across the Americas and was strongly supported in both analyses. Another lineage was distributed across Asia and consisted of four distinct clusters. Allele size homoplasy was found at the three microsatellite loci. We obtained better discrimination and resolution of the relationships among isolates with sequence data, although not all isolates could be typed. Thus sequencing of microsatellite flanking regions and repeats is a promising approach for the identification of Pfr isolates that specifically infect certain B. tabaci biotypes and phylogeographic studies.
Insights
Paecilomyces fumosoroseus (Pfr) genetic diversity was studied using microsatellites. Specific Pfr genotypes infect Bemisia tabaci, with distinct lineages found in the Americas and Asia.
Area of Science:
- Entomology
- Mycology
- Genetics
Background:
- Paecilomyces fumosoroseus (Pfr) is a widespread entomopathogenic fungus used in biological control.
- Understanding Pfr genetic diversity and population structure is crucial for its effective and sustainable application.
- Previous studies have not fully elucidated the genetic relationships and host specificity of Pfr isolates.
Purpose of the Study:
- To investigate the genetic diversity and population structure of Paecilomyces fumosoroseus (Pfr) isolates.
- To identify potential Pfr genotypes specifically associated with the insect pest Bemisia tabaci.
- To assess the utility of microsatellite markers and sequence data for Pfr phylogeographic studies.
Main Methods:
- Analysis of length and sequence polymorphisms in nine microsatellite loci across 33 Pfr accessions.
- Successful amplification and analysis were limited to Pfr isolates from Bemisia tabaci.
- Genetic relationships were inferred using allelic variability at eight polymorphic microsatellite loci and sequence data from flanking regions.
Main Results:
- Distinct Pfr genotypes specifically associated with Bemisia tabaci were identified.
- Phylogenetic analyses revealed two major genetic lineages of Pfr isolates from B. tabaci.
- One lineage was prevalent in the Americas, associated with the B-biotype, while the other, from Asia, comprised four distinct clusters.
- Allele size homoplasy was observed, but sequence data provided better resolution for isolate relationships.
Conclusions:
- Paecilomyces fumosoroseus exhibits significant genetic structuring, with specific lineages associated with Bemisia tabaci.
- Microsatellite markers, particularly when combined with sequence data of flanking regions, are effective tools for Pfr typing and phylogeography.
- This research provides a foundation for targeted use of Pfr in biological control programs against specific B. tabaci biotypes.
