Archivio Journal of Plant Pathology

Abstract:

In September 2011, licorice (Glycyrrhiza glabra) plants were observed in a field in the Iranian province of Yazd that showed symptoms consisting of wilting, leaf necrosis, vascular discoloration, and death of the plant. Fragments of vascular tissues plated on potato dextrose agar amended with 0.5 g/l streptomycin sulfate yielded white to pale-violet fungal colonies that produced macro- and microconidia. In carnation leaf agar medium, the macroconidia were three-septate and sickle-shaped whereas microconidia were elliptical, and formed abundantly in false heads. The 5.8S subunit and flanking internal transcribed spacer of the rDNA gene were amplified using the ITS1/ITS4 primers (White et al., 1990) and sequenced. The ITS sequence was 99% similar to that of F. oxysporum (GenBank accession No. JQ045558.1), hence confirming the observed morphological traits typical of this species (Nelson et al., 1983). Wounded roots of 4-week- old plants of G. glabra were dipped for 10 min in a conidial suspension (1x105 spores/ml), while control plants were dipped in sterile tap water. Seedlings were transplanted into pots (13x15 cm) and maintained in a growth chamber at 25°C. Typical symptoms on the leaves developed after five weeks and F. oxysporum was successfully re-isolated from artificially infected plants. Control plants remained symptomless. Previously, F. oxysporum had been reported as a root rot agent of Russian licorice (Glycyrrhiza uralensis) in China (Cao et al., 2013). To our knowledge, this is the first report of F. oxysporum causing wilt of G. glabra in Iran.