Influence of inoculated gut bacteria on the development of Bactrocera dorsalis and on its susceptibility to the entomopathogenic fungus, Metarhizium anisopliae

Abstract

Background Symbiotic interactions between insects and bacteria have been associated with a vast variety of physiological, ecological and evolutionary consequences for the host. A wide range of bacterial communities have been found in association with the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), an important pest of cultivated fruit in most regions of the world. We evaluated the diversity of gut bacteria in B. dorsalis specimens from several populations in Kenya and investigated the roles of individual bacterial isolates in the development of axenic (germ-free) B. dorsalis fly lines and their responses to the entomopathogenic fungus, Metarhizium anisopliae. Results We sequenced 16S rRNA to evaluate microbiomes and coupled this with bacterial culturing. Bacterial isolates were mono-associated with axenic B. dorsalis embryos. The shortest embryonic development period was recorded in flies with an intact gut microbiome while the longest period was recorded in axenic fly lines. Similarly, larval development was shortest in flies with an intact gut microbiome, in addition to flies inoculated with Providencia alcalifaciens. Adult B. dorsalis flies emerging from embryos that had been mono-associated with a strain of Lactococcus lactis had decreased survival when challenged with a standard dosage of M. anisopliae ICIPE69 conidia. However, there were no differences in survival between the germ-free lines and flies with an intact microbiome. Conclusions These findings will contribute to the selection of probiotics used in artificial diets for B. dorsalis rearing and the development of improved integrated pest management strategies based on entomopathogenic fungi.

Microbiota Perturbation or Elimination Can Inhibit Normal Development and Elicit a Starvation-Like Response in an Omnivorous Model Invertebrate

“…1A to G ; Table 1 ). These results were unexpected, as mono- and polycultural inoculation with typical or atypical gut bacteria could recover normal phenotypes in fruit flies and honeybees ( 2 – 4 , 41 , 42 ). Transcriptional profiling was used to illustrate how alterations of the gut microbial community affected major host gene networks involved in growth and development.…”

The Bacterial and Fungal Gut Microbiota of the Greater Wax Moth, Galleria mellonella L. Consuming Polyethylene and Polystyrene

“…This approach takes into account synergic effects that could arise from the joint metabolic activities of bacteria and fungi in relation to the environment (e.g., Cucini et al, 2020). It has been previously used to describe multi-kingdom ensembles and their behavior under different conditions, in insects of economic importance (Guo et al, 2020), in ruminants (Pitta et al, 2016), and in humans (Godoy-Vitorino et al, 2018). In our study, it helped to identify five taxa that co-occurred in all treatments and individuals, and thus may be participating in core processes.…”

“…In our study, it helped to identify five taxa that co-occurred in all treatments and individuals, and thus may be participating in core processes. This study also helped to evaluate the hypothesis that states that the dominance of some bacteria in gut communities may facilitate the entrance of entomopathogenic fungi (e.g., Gichuhi et al, 2020 ), which may have entered from the environment as a result of a depression of the immunological system driven by a low-quality diet such as plastics (e.g., Unckless et al, 2015 ). But this pattern was not supported by our data.…”

“…To measure co-occurrence between fungi and bacteria across the different plastic treatments, we calculated the Dice index using previously described methods and scripts (Godoy-Vitorino et al, 2018). The Dice index measures similarity between samples (Dice, 1945), with values that range between 0 (no co-occurrence) to 1 (maximum co-occurrence).…”

Production optimization, stability and oil emulsifying potential of biosurfactants from selected bacteria isolated from oil-contaminated sites

“…A nearly full-length sequence is said to be helpful for making a confident species or strain level identification [47], although several reports argued that a shorter sequence such as approximately 500 bp can also provide necessary divergence for the purpose [48,49]. In fact, both 500 and 1500 bp are common lengths to be sequenced and compared for phylotype determinations, and sequences of various lengths are found in databases and the literature [49][50][51][52][53][54][55][56][57]. Nevertheless, analysis of a nearly full-length sequence of the 16S rRNA gene is usually recommended, especially when reporting a new species or when it is necessary to differentiate between specific strains in a genus.…”