FIRST REPORT OF SCLEROTINIA SCLEROTIORUM CAUSING

Abstract

In September 2015, approximately 50% of Lens culinaris plants were observed in some farmland in Qazvin province (Iran) showing disease symptoms including rotting in stem, pod, flower and leaves. To obtain pure cultures, fourteen sclerotia were collected from the field, disinfected with 1% NaOCl, placed on potato sucrose agar (PSA) with 100 µg/ml streptomycin, incubated at 22°C in the dark for 10 days and identified based on white mycelium and a ring of large sclerotia at the margin of the plates. The sclerotia were dark brown and 3.5±0.7 mm in size on the average. On the basis of morphology, the fungus was identified as Sclerotinia sclerotiorum (Lib.) de Bary (Bolton et al., 2006). To confirm the identification, internal transcribed spacer (ITS) region of rDNA amplified using the ITS1-ITS4 primer pair (White et al., 1990) and the amplified PCR products were sequenced (five isolates). The BLAST search revealed that our sequence (GenBank accession No. KY049841) had 99% identity with reported sequences of Sclerotinia sclerotiorum (Ahmed and Akhond, 2015) (HQ833450, KX427540 and KT970793). For pathogenicity test, seven healthy 2-month-old lentil plants were inoculated by placing the inoculum on the base of the stem and kept at room temperature (24°C). Plants were inoculated with a plug of non-colonized PSA as controls. After 2 weeks, dark brown sclerotia were apperceived on the soil surface along with white fluffy mould. The pathogen was re-isolated from symptomatic plant parts, whereas the control plants remained symptom-free. To our knowledge, this is the first report of Sclerotinia sclerotiorum causing Sclerotinia rot on L. culinaris in west of Iran