Abstract
Entomopathogenic fungi are one of the key regulators of insect populations in nature. Some species such as Beauveria bassiana with a wide host range have been developed as promising alternatives to chemical insecticides for the biocontrol of insect pests. However, the long-term persistence of the released strains, the effect on non-target hosts and local fungal populations remains elusive, but they are considerable concerns with respect to environmental safety. Here we report the temporal features of the Beauveria population genomics and evolution over 20 years after releasing exotic strains to control pine caterpillar pests. We found that the isolates within the biocontrol site were mostly of clonal origins. The released strains could persist in the environment for a long time but with low recovery rates. Similar to the reoccurrence of host jumping by local isolates, the infection of non-target insects by the released strains was evident to endemically occur in association with host seasonality. No obvious dilution effect on local population structure was evident by the releases. However, the population was largely replaced by genetically divergent isolates once per decade but evolved with a pattern of balancing selection and towards expansion through adaptation, non-random outcrossing and isolate migration. This study not only unveils the real-time features of entomopathogenic fungal population genomics and evolution but also provides added values to alleviate the concerns of environmental safety regarding the biocontrol application of mycoinsecticides.
Highlights
These authors contributed : Lijuan Mei, Mingjun Chen
To examine the possibility of gene flow with other populations, field collections were conducted at other sites across the monsoon region (MR including those from regions south and north (MR2) of the AH site) and non-monsoon region (NMR) of China (Fig. 1)
We report the ecological and evolutionary scenario through time of a population of B. bassiana from a forest farmland after releasing exotic strains to control caterpillar pests for 20 years
Summary
Studies of a few classical releases of different Entomophthoralean fungi revealed that either the long-term persistence of an Australian strain of the grasshopper pathogen Entomophaga grylli in North America was questionable [5] or it might have taken decades for the establishment of a Japanese species of Entomophaga maimaiga in North America to suppress the population of gypsy moth [6] In contrast to these classical introductions, ascomycete fungal BCAs are conventionally used as mycoinsecticides. We investigated the fate and consequence of the biocontrol applications It remains obscure whether the released strains could persist in the released site for a long time to infect the non-target insects and whether there were dilution, replacement and/or recombination effects of biocontrol introductions on local populations. Regarding the dominant arms-race model of fungus–plant interactions in managed ecosystems, we asked if this was the case for our system as well? In addition, we determined the population demography by examining the possibility of isolate migration and gene flow
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
