Tomatoes, bananas, cabbages, melons, pumpkins and cucumbers… are just some of the 150 crops of commercial interest that are victims of Fusarium oxysporum, one of the most important pathogens in the world due to the millions of dollars in losses it is responsible for and its ability to attack different types of plants. Although it can go unnoticed in the soil for more than 30 years, when it detects the roots of a host plant, it grows towards them, colonizing its vascular system and causing crops to wilt.
The application of fungicides, rotation, and the development of resistant varieties are some of the agricultural practices that have proven to be insufficient to control it, due to its high adaptability. Now, the Fungal Pathogenesis Molecular Genetics research group at the University of Cordoba has managed to attenuate the virulence of the pathogen by developing a new strategy: genetically altering a cellular pathway, making it 'believe' that it has the necessary resources without the need to infect crops.
The key: 'confusing' the fungus
What would happen if an individual in need of food received a series of chemical signals indicating to him that, on the contrary, he was satiated and had sufficient resources? This is, despite the obvious differences, the approach upon which the scientific work was based.
"For decades it has been hypothesized that nutrient starvation is a signal that triggers infection," explains researcher Manuel Sánchez, one of the authors of the study. Based on this premise, the study has eliminated a gene from the fungus, which codes for a protein called Tsc2. By eliminating this protein, according to the results of the study, it is possible to permanently activate a cellular pathway that is set in motion naturally when the pathogen has the necessary nutrients.
"It's like telling the fungus that it doesn't need resources, creating confusion," the researcher stressed. Despite the fact that the microorganism is in an environment in which it should set its infection mechanisms in motion, it receives a set of signals that tell it that it has the necessary nutrients to survive without needing to infect anything. In short, it is a matter of playing, genetically, with its hunger, a bit of chemical trickery.
According to the results of the study, published in the scientific journal Molecular Plant Pathology and carried out by means of infection tests on tomato plants, this genetically modified strain of Fusarium oxysporum reduces its capacity to penetrate and adhere to the root, thus attenuating its virulence.
The work, in which the researchers Gasabel Yaneth Navarro Velasco and Antonio Di Pietro also participated, brings to the fore a medium- and long-term objective: to develop an antifungal strategy that replicates this response outside the laboratory.
Reference:
Constitutive activation of TORC1 signalling attenuates virulence in the cross-kingdom fungal pathogen Fusarium oxysporum. Gesabel Yaneth Navarro-Velasco, Antonio Di Pietro, Manuel Sánchez López-Berges. Mol Plant Pathol. 2023 Apr;24(4):289-301. doi: 10.1111/mpp.13292. Epub 2023 Feb 24