Archivio Journal of Plant Pathology

Abstract:

Tomato plants showing the symptoms of leaf blight were observed in March 2015 in the tunnels on the premises of the University of the Punjab, Lahore, Pakistan. Initial symptoms were water- soaked flecks of brown color, which coalesced later to form dark brown lesions. Diseased leaves were collected and a fungus was isolated on potato dextrose agar (PDA) plates incubated at 25 ± 2°C. Fungal colonies were dark brown, and usually zonate. Conidia were ellipsoidal, smooth, 3- septate, with middle cells broader and darker than two end cells and had a size of 18-32×8-16 μm. Conidiophores were septate, pale brown, smooth, and up to 800 μm long (Ellis, 1971). Total DNA was isolated from the mycelium and the internally transcribed spacer (ITS) region was amplified (White et al., 1990) and sequenced (GenBank accession No. LN879930). BLAST analysis of the fungal sequence showed 100% nucleotide similarity with Curvularia aeria accession Nos. KP340067.1, KP340066.1, KP131919.1, and EU680523.1. Based on its morphological and molecular features, the fungus was identified as Curvularia lunata var. aeria (Bat.) M.B. Ellis. C. lunata var. aeria is a taxon accepted as a variety of C. lunata, which is distinguished from C. lunata var. lunata because of the faster and floccose mycelial growth. Pathogenicity was assessed by reproduction of symptoms on inoculated healthy plants, which fulfilled Koch’s postulates. To our knowledge, this is the first report of the presence of C. aeria on tomato in Pakistasn.