Archivio Journal of Plant Pathology

Abstract:

Giant cane (Arundo donax) is a monocotyledonous plant belonging to the family Poaceae, whose stems are used in handicrafts and paper industry (Dudley, 2000). Blight of leaf sheaths and stem lesions with a light brown coloured center, surrounded by a darker brown line were observed on A. donax plants in different regions of the Mazandaran province (Iran). Fragments form symptomatic tissues were washed, surface-disinfected with 70% ethanol and a 1% sodium hypochlorite (NaClO) solution and plated on potato dextrose agar (PDA). Fungal cultures displayed a ì white floccose mycelium that turned often violet with age. A violet pigment that darkened with age was released in the medium. Microconidia were abundant, oval or globose shaped whereas a limited number of 3-5 septate macroconidia was produced. Micro- and macroconidia were ca. 5-10×1 and 15-30×2-3 μm in diameter, respectively. Based on morphological features, the disease agent was identified as Fusarium globosum (Leslie and Summerell, 2006), a result that was confirmed by amplifying by PCR the translation elongation factor (TEF) region (Jurado et al., 2010) and sequencing the obtained product (a 600 bp amplicon). This sequence was then compared with related sequences from GenBank. BLAST analysis of a 600 bp fragment showed 100% similarity with Fusarium globosum (accession No. KJ746615). Pathogenicity tests were conducted by placing mycelial plugs taken from the margins of 3-day-old colonies on the stem of healthy plants. The same symptoms appeared one week after inoculation. Fusarium globosum was previously reported on corn, wheat and barley in Iran (Darvishnia et al., 2005). This is the first report of Giant cane Fusarium sheath blight in Iran.