Phytotoxic and antifungal compounds for agriculture are interestingly produced by the endophytic fungus Fusarium sp. (Ascomycota) isolated from Piper sp. (Piperaceae)

Authors: BARRETO, DEBORA - Universidade Federal De Minas Gerais; Cantrell, Charles; Kim, Seong Jong; DE CARVALHO, CAMILA - Universidade Federal De Minas Gerais; DE QUEIROZ, SONIA CLAUDIA - Embrapa; Bajsa Hirschel, Joanna; Tamang, Prabin; DUKE, STEPHEN - University Of Mississippi; ROSA, LUIZ HENRIQUE - Universidade Federal De Minas Gerais

Submitted to: Annals of the Brazilian Academy of Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2025
Publication Date: 8/18/2025
Citation: Barreto, D.L., Cantrell, C.L., Kim, S., De Carvalho, C.R., De Queiroz, S.D., Bajsa Hirschel, J.N., Tamang, P., Duke, S.O., Rosa, L. 2025. Phytotoxic and antifungal compounds for agriculture are interestingly produced by the endophytic fungus Fusarium sp. (Ascomycota) isolated from Piper sp. (Piperaceae). Annals of the Brazilian Academy of Science. 97:e20241059. https://doi.org/10.1590/0001-3765202520241059.
DOI: https://doi.org/10.1590/0001-3765202520241059

Interpretive Summary: Endophytic fungi are microorganisms that colonize plant tissues for part or all of their life cycle without causing any apparent adverse symptoms in the plants. In symbiosis with their host plants, these fungi can provide defense against pathogens and herbivores by producing metabolites, while acquiring nutrients and protection. These microorganisms can synthesize a wide variety of chemically distinct metabolites, exhibiting diverse activities relevant to medicinal, industrial, and agricultural applications. Once isolated and identified, these metabolites can be investigated for their potential as biopesticidal agents. The phytotoxic and antifungal activities of metabolites isolated from Fusarium sp., an endophyte associated with the medicinal Tropical Rain Forest plant Piper sp., were evaluated. Chromatographic separations of the Fusarium sp. crude extract led to the isolation of three analogous compounds. The isolated compounds were evaluated for phytotoxic activity against lettuce and bentgrass. All compounds exhibited strong phytotoxic activity on both plant species, completely inhibiting seed germination at a concentration of 1 mg mL-1. The structures of these compounds could serve as scaffolds for the development of new pesticides.

Technical Abstract: The phytotoxic and antifungal activities of metabolites isolated from Fusarium sp., an endophyte associated with the medicinal Tropical Rain Forest plant Piper sp., were evaluated. Chromatographic separations of the Fusarium sp. crude extract led to the isolation of three analogous compounds: anhydrofusarubin (1), 5,10-dihydroxy-1,7-dimethoxy-3-methyl-1H-benzo[g]isochromene-6,9-dione (2), and javanicin (3). The structures of the isolated compounds were determined by high-resolution mass spectrometry (HRMS) analysis and direct comparison of 13C NMR data with that reported in the literature. The isolated compounds were evaluated for phytotoxic activity against Lactuca sativa and Agrostis stolonifera. All compounds exhibited strong phytotoxic activity on both plant species, completly inhibiting seed germination at a concentration of 1 mg mL-1. Additionally, the isolated compounds were evaluated against Lemna paucicostata, achieving a 50% growth inhibition (IC50) at concentration of 64, 28, and 31 µM for compounds 1, 2, and 3, respectively. The antifungal activity of these compounds was evaluated using a bioautography assay targeting the agricultural pathogen Colletotrichum fragariae. Only compound 2 demonstrated significant antifungal activity. Our results showed that tropical medicinal plants harbor an interesting endophyte that has a potential reservoir of bioactive compounds. Moreover, the structures of these compounds could serve as scaffold for the development of new pesticides.