Archivio Journal of Plant Pathology

Abstract:

In May 2012, Convolvulus arvensis plants with irregular tan-colored necrotic lesions on the leaves were observed near Ondokuz Mayis University (Samsun, Turkey). Leaves with lesions were surface-disinfected for 5 min in 10% bleach followed by incubation at 20-25°C in a moist chamber. Pycnidia developed after 5-7 days, and pure cultures were obtained by transferring conidia from pycnidia onto oatmeal agar. Colonies were peach-colored, and did not change color with the addition of NaOH. Pycnidia in culture were scattered, globose, 119.6 μm in diameter, with one papillate ostiole (average 29.7 μm in diameter) with glabrous and elongated necks (average 199.5 μm in length). Conidia were aseptate, hyaline, and ellipsoidal to oblong (average 8.1×2.7 μm). Conidial matrix color varied from gray to flesh to salmon. These characters matched the description of Phoma macrostoma Mont. var. macrostoma (Boerema et al., 2004). A specimen was deposited with the US National Fungus Collections (BPI 892537). DNA sequences for the internal transcribed spacers (GenBank accession No. KC590613) aligned, after BLAST analysis, 97% to 10 isolates of P. macrostoma var. macrostoma and 99% to two isolates of P. macrostoma (GenBank Accession Nos HM755951 and DQ474091). Conidia were spray-inoculated, in a suspension of 106 conidia ml-1, onto twenty 30-day-old C. arvensis plants; another 10 control plants were sprayed with water only. Plants were placed in a dew chamber at 25°C for 40 h, then moved to a 20-25°C greenhouse. All inoculated plants but none of the controls, became diseased. P. m. var. macrostoma was re-isolated from all inoculated plants. To our knowledge this is the first report of P. m. macrostoma from C. arvensis.