Scientists developed a method to genetically modify a harmful fungus called Fusarium acuminatum that causes root rot in plants like carnations. Using a technique that breaks down the fungal cell wall and uses a special chemical (PEG) to insert genes, they successfully added a green-glowing protein (GFP) marker to the fungus. This allows researchers to track where and how the fungus infects plants. The modified fungus still behaves normally, making it a useful tool for identifying which genes make the fungus dangerous, potentially leading to better disease control methods.