Plant Growth-Promotion and Antifungal Features of Streptomyces sp. AM25 Unveiled by a Metabologenomics Approach

Actinobacteria have emerged as a rich source of bioactive compounds with multiple agricultural applications, ranging from the production of phytohormones to specialized metabolites, which are useful for the biological control of plant pathogens. With the growing demand for more sustainable agricultural practices and the need to reduce the use of agrochemicals, these bacteria and their metabolites offer a promising alternative for the development of microorganism-based biological products. In this study, we evaluated the beneficial agricultural features of the actinobacterium Streptomyces sp. AM25, isolated from the Brazilian Amazon region, focusing on its bioactivity against plant pathogens and its ability to promote maize growth. We employed integrated genomic and metabolomic approaches to characterize the mechanisms underlying its bioactivity. Genomic analysis revealed the presence of gene clusters associated with the production of specialized metabolites and enzymes for the acquisition of essential nutrients for plant development. Complementary metabolomic analysis identified bioactive compounds with antifungal and antibacterial potential. In vitro assays demonstrated the efficacy of AM25 against a range of phytopathogenic fungi, including major pathogens of maize, soybean, and tomato crops, suggesting its promising use as a biological control agent. Finally, this isolate and its sole metabolites were able to improve shoot dry weight and the shoot-to-root ratio on maize plants. These results clearly highlight the Streptomyces sp. AM25 strain as a viable candidate for the development of sustainable plant protection solutions.