Fungi in the roots activate defense mechanisms among broccoli plants.

Researchers have described a communication mechanism between broccoli plants mediated by an endophytic fungus. Trichoderma hamatumThey show that a plant's leaf infection by Sclerotinia sclerotiorum triggered defense responses in a neighboring plant connected by fungal hyphae in the roots. This effect appeared only in the presence of Trichoderma hamatum.

The study used an axenic system with two plants. The arrangement allowed control of the hyphal connection between the roots and measurement of colonization, gene expression, and metabolic profile in roots, leaves, and mycelium. According to the authors, the recipient plant gained protection against the necrotrophic pathogen, with reduced leaf lesions, greater tissue vitality, and less oxidative damage.

In trials with two plants and inoculation of Trichoderma hamatumThe lesion area decreased to 1,08 ± 0,48 cm² when the neighboring plant had been infected 48 hours prior. In the treatment without this pre-infection, the lesion remained at 7,18 ± 0,18 cm². Without the fungus, the pre-infection of the neighboring plant did not generate a relevant difference between the treatments.

The authors also did not detect significant metabolic changes in the mycelium of Trichoderma hamatum among the conditions evaluated. This result indicates that protection between plants depended on root colonization by the fungus, and not on a metabolic reprogramming of the mycelium.

In the recipient plant, the activation of defense mechanisms involved hormonal rebalancing. In the roots, there was an increase in responses associated with salicylic acid. In the leaves, the defense linked to jasmonic acid predominated. Metabolomics also indicated an accumulation of compounds associated with defense, such as neoglucobrassicin in the roots and lipids in the aerial parts.

The authors highlight that the work expands the concept of "wired communication" between plants to non-mycorrhizal endophytic fungi. The study also validates the phenomenon in a crop of agricultural interest. In the group's assessment, the result opens up opportunities to explore fungal connectivity as a tool in the sustainable management of diseases.

Further information at doi.org/10.1016/j.plantsci.2026.113104