Fusarium sporotrichioides: a novel pathogen of lilies (Lilium)

Lilies ( Lilium spp.) are among the most important cut flowers. Fungal diseases can severely reduce lily yield and quality, resulting in significant economic losses. In 2023, wilting symptoms were observed in lilies at a hobby garden in Hungary. Microscopic observations of a wilting stem piece revealed typical macroconidia of the genus Fusarium . The single-conidial G300 fungal isolate was characterized as Fusarium sporotrichioides by the development and shape of micro- and macroconidia and the culture characteristics. The internal transcribed spacer region of the nrDNA (ITS), the translation elongation factor 1-alpha ( TEF1 ), and the second largest subunit of the DNA-directed RNA polymerase ( RPB2 ) loci were amplified, and the BLAST searches showed 99–100% identity with the corresponding F. sporotrichioides sequences in GenBank. In the phylogenetic analysis of the combined TEF1 and RPB2 sequences of the G300 isolate, it was grouped in one clade with other representative F. sporotrichioides isolates. Pathogenicity of G300 was confirmed by artificial inoculation of lily stems and detached leaves. Microscopic examinations and sequencing of the above-mentioned genes confirmed that the inoculum and the re-isolated fungus were consistent, thus fulfilling Koch’s postulates. Fusarium sporotrichioides prefers warm and moist conditions, causing symptoms on stems and leaves. As the disease progressed, the pathogen spread downwards through the plant, and the plants showing symptoms did not recover. This is the first report of the species F. sporotrichioides causing wilt in lilies.