Abstract
The fungal entomopathogen Beauveria bassiana is ubiquitous in below-ground systems; however, there is a dearth of information on the above-ground diversity, temporal and spatial distribution of this fungus. Therefore, we assessed its occurrence in a conifer forest (Pseudotsuga monziesii and Pinus nigra var. maritima) using selective media to isolate B. bassiana from soil, branch and bark samples collected in October 2005, March and June 2006. Fungal density was the highest at all locations in October, declining in March and June, and absent from conifer branches in June. This above-ground decline most likely resulted from more extreme environmental conditions compared with those below ground. Molecular analyses (ISSR-PCR) indicated that B. bassiana is genetically diverse, comprising both distinct microhabitat-specific and seasonal isolates. The occurrence of dissimilar above- and below-ground isolates suggests that B. bassiana occupies various overlapping niches in these systems.
Highlights
The globally ubiquitous anamorphic genus Beauveria (Ascomycota: Hypocreales) is thought to have a broad host range and has received considerable attention as a potential biological control agent of pest insects
It is generally assumed that genetic groups of B. bassiana have coevolved with particular host taxa (Couteaudier & Viaud, 1997; Berretta et al, 1998; Gaitan et al, 2002); yet recent studies suggest that B. bassiana includes generalist entomopathogens (Wang et al, 2003; Rehner & Buckley, 2005)
Little is known about the community ecology of B. bassiana in natural habitats, which would be invaluable in further developing our understanding of the ecology of this fungus
Summary
The globally ubiquitous anamorphic genus Beauveria (Ascomycota: Hypocreales) is thought to have a broad host range and has received considerable attention as a potential biological control agent of pest insects. Environmental factors are speculated to determine the patterns of distribution of B. bassiana because particular phylogenetic associations with the insect host appear to be singularly absent (Bidochka et al, 2002; Meyling et al, 2009). If B. bassiana is widely distributed above ground, we might expect that there are separate genetic groups of isolates adapted to the different environmental conditions associated with foliage and bark compared with soil. There is a precedence for genotype selection in relation to habitat type, for example, Bidochka et al (2002) identified distinct genetic groups associated with the soil from three different (forest, agricultural and arctic) Canadian habitats. Genetic groups isolated from Arctic and forested habitats grew at lower temperatures relative to those from the agricultural habitat, which proved tolerant of UV exposure (Bidochka et al, 2002)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
