Antagonistic effect of symbiotic bacteria isolated from midgut of honey bee workers against Ascosphaera Apis, the causal pathogen of chalkbrood disease

Abstract EN

Six biotypes of fungal Isolates belonging to Ascospbaem apis were Isolated by three media from Infested honey bee larvae.

Two isolates (A7 and A15) were able to form sporocysts.

However, the other four (A3, A4, As and As) did not form sporocyts on cultivated Murashieg and Skoog medium (mMS).

Six isolates from symbiotic bacteria associated with midgut of honey bee workers have been Isolated from healthy workers.

Four isolates from endospore-fonning bacteria belonged to Bacillus subtills (Bz, Bi, Bio and Bioo) and two isolates from non endospore-fonning bacteria to Pseudomonas fluorescence (Pi and Ps) were Isolated.

Morphological features and physiological reactions of isolated bacteria were determined.

Antagonistic effectiveness of both Bacillus subtills and Pseudomonas fluorescence was tested against isolates of Ascosphaera apis, the causal pathogen of chalkbrood disease, In vitro.

Data showed that Bacillus subtills isolate (B2) gave the highest antagonistic effect as inhibition zone and mycelial growth followed by Pseudomonas fluorescence (Pi).

Highly significant differences among Bacillus subtills (Bz), Pseudomonas fluorescence (Pi) and other bacterial strains were recorded.

Scanning electron microscope was used to examined the fungal hyphae and mature sporocysts of Ascosphaera apis which isolated from infested larvae and grown on (mMs).

Numerous distinguish differences were recorded.

The examination showed that numerous bacterial cells of Pseudomonas fluorescence invaded fungal hyphae of Ascosphaera apis and caused disintegration the cell walls.

Whereas Bacillus subtills hyphae showed shrinking appearance.

It could be conducted that such symbiotic bacteria can considered as a bioformula for controlling such disease in honey bee colonies.