First report of Curvularia gladioli causing leaf spots on Gladiolus gandavensis in China

Gladiolus (Gladiolus gandavensis Van Houtte) is a perennial plant in the family Iridaceae, which shows sword-shaped leaves and spikes of brilliantly colored irregular flowers arising from corms. It one most important fresh cut widely cultivated worldwide, including China. In September 2020, white pinpoints were first observed on gladiolus Jiangmen City, Guangdong Province, The spots eventually turned brown. lesions then developed into oval to circular spots, surrounded with an obvious yellow halo. expanded coalesced, causing leaf blight. These symptoms approximately 10% plants fields measuring ca. 70 ha. Symptomatic sampled fields, surface sterilized 75% ethanol for 30 s, submerged 2% NaOCl solution 10 min, rinsed three times sterile water. samples pieces (5 × 5 mm) incubated 4 d potato dextrose agar (PDA) at 25°C. A representative fungal colony was subcultured onto new PDA grown another 7 d, its mycelium appeared be grayish-black villiform. This strain named as Cg_TS. Its conidiophores simple, septate, cylindrical shape, moderate brown color. They occurred singly or groups. straight slightly flexuous ranged size 57.0 80.0 μm 4.0 8.0 μm. Conidia 3-distoseptate curved third cell base. swollen side larger than other cells. conidia 23.5 32.0 11.5 16.0 morphological characteristics consistent description Curvularia gladioli Boerema & Hamers (Boerema 1989). Using primer pair ITS1 ITS4, PCR applied amplify internal transcribed spacer (ITS) region rDNA. sequence (GenBank accession No. MW426196.1) subjected BLAST GenBank, suggesting that it similar C. sequences, LT631345.1 HG778987.1, both 99.49% similarity. To fulfill Koch's postulates, healthy two-month-old used pathogenicity testing, wounded by pressing pipette tip. Mycelium disks (3 mm diameter) plants. Another inoculated served control. Inoculated placed greenhouse 25°C 90% relative humidity. After 3 all pathogen-inoculated leaves. those initially re-isolated symptomatic tissue. Identification confirmed observation ITS sequencing. Control remained symptomless. curvularia fungus firstly reported Florida 1947 spread globally via infected corms (Torre et al. 2015), also cause Brazil 2013 (Torres 2013). Although had been recorded species occurring China (Zhang 2006), not Province elsewhere our knowledge, this report pathogen will help develop diagnostic methods seedlings, may lead development appropriate chemical management strategies.