Summary: | This study presents the first report of a <i>Fusarium</i> wilt in <i>Cymbopogon citratus</i> in Portugal. <i>Fusarium</i> is one of the most prominent genera of plant pathogens due to its wide range of hosts and mycotoxin production. The <i>Fusarium fujikuroi</i> species complex (FFSC) encompasses several threatening known plant pathogens. <i>Cymbopogon citratus</i> is a broadly distributed aromatic and medicinal plant rich in bioactive volatiles, which are relevant to several industries. The primary goal of this study was to identify and characterize the <i>Fusarium fujikuroi</i> species putatively responsible for the observed wilt. This report displays symptomatologic, cultural, morphologic, genetic, and cytogenomic characteristics associated with this fungus and disease. The cultural features included flat, white-colored colonies with filiform margins. Additionally, these colonies displayed abundant cottony aerial mycelia at the upper surface and orange-violet color at the lower surface. On Carnation Leaf-Piece Agar, septate fusoid macroconidia were present, displaying a flattened tapering toward the basal part and a number of septa ranging from one to four. The comparison between the amplified and aligned ITS sequences revealed 100% similarity between the isolate and the FFSC. Finally, a flow cytometry assay revealed an estimated genome size of 29.9 Mbp. This finding contrasts with other known pathogens from the <i>Fusarium fujikuroi</i> species complex. Ultimately, novel pathogens might be uncovered by exploring the mycobiome of diseased <i>Cymbopogon citratus</i> plants.
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