Molecular networking as a tool to annotate the metabolites of sp. and isolates and evaluate their fungicidal effects against and .

Unlabelled: Rhizobacteria are valuable sources of compounds that can be used for the integrated management of diseases in rice. Here, we aimed to explore the metabolism and organize and annotate the metabolites of sp. and isolates using molecular networking and evaluate their fungicidal effects against and We obtained bacterial extracts after 6 and 16-h incubation via liquid-liquid extraction using ethyl acetate as solvent. We performed UHPLC-MS analysis and data processing using molecular networking and conducted biological assays in rice plants. Using the Global Natural Product Social spectral libraries, we annotated the following compounds: austinoneol, Phe-Pro, -acetyl-l-leucine, Leu-Gly, Ile-Leu, Phe-Pro, 2,5-piperazinedione, 3-(1H-indol-3-methyl)-6-methyl-cyclo(d-Trp-l-Pro), and cholic acid. Results of the biological assays showed that the bacterial extracts reduced the mycelial growth of both pathogens in all treatments compared to the control. In the greenhouse setup, 8 days after the challenge for leaf gray spot and leaf blast, all treatments affected up to 4.4% of the leaf area, with an area under disease progress curve of 13.24, showing significant difference compared to the control, which affected 23% of the leaf area, with an AUDPC of 44.65. Our study provides potential new sources of natural products to be applied in the integrated management of rice.

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03547-6.