FIRST REPORT OF CURVULARIA SPICIFERA CAUSING LEAF SPOT ON TOMATO SOLANUM LYCOPERSCIUM L IN EGYPT
A.M. Ismail, T.A. Essa, S.M. Kamel, G. Perrone
In summer of 2014, brown to black necrotic lesions surrounded by yellow haloes were observed on leaves of tomato plants cultivated in Behira governorate. Isolation was made from 3−5 mm2 pieces of lesions margins onto potato dextrose agar (PDA) after surface disinfected using 0.5% NaOCl. The examined morphological features (colony and conidia) were reminiscent of Curvularia spicifera as described by Jeon et al. (2015). The identity was further confirmed by DNA amplification and sequencing of the glyceraldehyde-3-phosphate dehydrogenase (gpd) and second largest subunit of RNA polymerase II (rpb2) gene regions using the same primer sets used in the study of Madrid et al. (2014). Sequences of gpd and rpb2 were deposited in GenBank under accession Nos. KU133371 and KU133372, respectively, and revealed similarity 100% to (KC928089) and 99% to (HF934818) of C. spicifera.
Koch’s postulates were further confirmed using surface disinfected leaves cv. Super strain-B wounded by sterile needle. Approximately 3-mm2 of colonized PDA plugs of 7-days-old cultures were placed on the wounded sites. Control leaves and fruit were wounded and inoculated with sterile PDA plugs. Tomato leaves were placed at room temperature (28−30°C) and 80% of RH. Five days later, brown circular necrotic lesions (2-3 mm2) were developed on the inoculated leaves. The control leaves showed no symptoms. Re-isolation from infected tissues revealed C. spicifera and its identity was morphologically confirmed. To our knowledge this the first report of C. spicifera (Bainier) Boedijn causing leaf spot on tomato in Egypt.