Natural compound and graphene oxide team up to fight Fusarium wilt in cyclamen

A combination of a natural plant-derived compound and graphene oxide, derived from graphite, has shown promising results in controlling Fusarium wilt, the leading disease affecting Cyclamen production in Brazil. Commonly known as cyclamen, the ornamental plant is gaining ground in the country’s production sector. Brazil accounts for around 40% of the South American market for the species. The strategy was developed through a collaboration between Embrapa Environment (SP), the State University of Campinas (Unicamp), and PPS Compósitos.

The natural plant-derived compound is β-caryophyllene, a molecule found in various plants and associated with plant defense mechanisms. Identified in cyclamen plants following fungal infection, it was tested both in isolation and in combination with graphene oxide. The study showed that this pairing extends the action of β-caryophyllene by reducing the impact of its high volatility. Graphene oxide, derived from graphite, acts as a bioprotector by forming a layer that limits the loss of the active ingredient and prolongs its effect on the plant.

According to Andre May, researcher at Embrapa Environment, laboratory tests showed that β-caryophyllene inhibits the growth of Fusarium oxysporum, while graphene oxide alone produced no significant effect.

However, the combined application of both agents to Cyclamen plants, whether by spraying or endotherapy (direct injection into the bulbs), revealed a synergistic effect that increased treatment efficacy. “In addition, graphene oxide acts as an adsorbent, retaining the substance on its surface, for fusaric acid, a toxin produced by the fungus, thereby reducing the damage caused to the plant,” adds researcher Bernardo Vieira.

Researcher Kátia Nechet adds that greenhouse experiments showed that the combination of β-caryophyllene and graphene reduced mortality in infected plants by 40% and slowed disease progression. The treatment also promoted aerial biomass growth in cyclamen and advanced flowering by 11%, demonstrating direct effects on productivity and the ornamental value of the flowers.

Sustainability and cyclamen disease control

Cyclamen, grown in Holambra (SP), faces phytosanitary challenges due to pathogens present in the production environment, particularly Fusarium, which can kill up to 70% of plants in commercial crops. The disease interferes with plant physiology, compromising development and causing plant death. In this context, disease control alternatives are essential.

β-Caryophyllene, found in species from the Asteraceae and Cannabaceae families, had already been identified as a molecular signal capable of activating plant defenses. The compound was identified by analyzing the volatile emissions of cyclamen plants after inoculation with Fusarium.

Since the molecule is produced by the plant itself, the scientists chose to apply it in larger quantities in order to strengthen the plant’s defenses against the disease-causing fungus. Researcher Sônia Queiroz notes that in vitro studies showed that β-caryophyllene reduces the growth of F. oxysporum by up to 40%, contributing to disease control.

“For its part, graphene oxide, due to its unique structure, can provide a protective effect for beneficial substances against degradation,” highlights analyst Márcia Assalin.

The researchers applied the treatments to two Cyclamen genotypes, “Verano Red Solar” and “Magenta”, using both spraying and endotherapy. The combined application of β-caryophyllene and graphene was found to delay the onset of Fusarium wilt symptoms by up to 26 days. The greater efficacy is attributed to graphene oxide’s ability to adsorb and stabilize β-caryophyllene, protecting it from volatilization and degradation.

Natural compound shows additional benefits
To ensure environmental safety, the team carried out ecotoxicological tests of β-caryophyllene on organisms across different trophic levels, including microalgae, aquatic plants, microcrustaceans, and nematodes. “The results indicated low toxicity in the majority of species, which made it possible to determine safe concentrations for aquatic environments,” reveals researcher Claudio Jonsson.

Beyond disease control, the research revealed additional effects of β-caryophyllene, including increased growth, greater biomass, and earlier flowering, all significant benefits for the commercial production of Cyclamen.

For May, the study highlights the potential of the combined use of β-caryophyllene and graphene oxide as an innovative and sustainable strategy to protect ornamental plants, reduce economic losses, and extend the shelf life of flowers.

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