To select a strain that effectively inhibits the growth of Aspergillus flavus.
Effective strains were screened using the streak plate method and the confrontation culture method of Aspergillus flavus. The species of the effective strain was determined through morphological observation and 16S rRNA gene analysis. The effect of the effective strain in inhibiting the growth of Aspergillus flavus was verified through experiments of Aspergillus flavus infecting corn and peanut kernels. By using transcriptome sequencing technology, the fermentation broth of the effective strain G10 was co-cultured with Aspergillus flavus for different periods of time, in order to determine the interaction mechanism between the effective strain and Aspergillus flavus.
The strain G10 that inhibited the growth of Aspergillus flavus was selected. It was identified that the effective strain G10 had a 99.93% similarity in the 16S rRNA gene with Burkholderia stagnalis. It belonged to the Burkholderia stagnalis and was named Burkholderia stagnalis G10. The application experiments on infecting corn and peanut kernels had verified that strain G10 had a significant antagonistic effect against Aspergillus flavus. Transcriptome sequencing revealed that the number of differentially expressed genes in strain G10 when co-cultured with Aspergillus flavus for 24 hours was 3341, among which 1830 genes showed up-regulation and 1511 genes showed down-regulation. The number of differentially expressed genes when co-cultured for 48 hours was 5334, among which 2429 genes showed up-regulation and 2905 genes showed down-regulation. Enrichment analysis revealed important gene ontology (GO) entries such as metabolic process, cell process, cell structure components, catalytic complex, etc., and important Kyoto encyclopedia of genes and genomes (KEGG) pathways such as carbon metabolism, amino acid biosynthesis, ribosome generation process, protein processing process, etc.
The selected effective strain G10 can effectively inhibit the growth of Aspergillus flavus, providing a reference for further research on the interaction mechanism between bacteria and Aspergillus flavus and the application of biocontrol bacteria.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |