Journal of Plant Pathology Archive

Abstract:

In December 2013 and January 2014, symptoms appeared in North India on gladiolus leaves as small, brown spots, that expanded over time to the whole plant, spikes included, which became covered with a layer of grayish mycelium and conidia. Forty isolates of a fungus recovered from diseased plants were grown on potato dextrose agar (PDA) and their morphological characteristics recorded after incubation for one week at 25°C. Conidia observed under a scanning electron microscope were single-celled, ovoid to ellipsoid, colorless, smooth and measured 9.99 x 7.47 μm. Conidiophores were slender and branched with enlarged apical cells bearing clusters of conidia. These cultural and morphological characteristics conform to those described by Ellis (1971) for Botrytis cinerea. To confirm the identity of the fungus, single-spore isolates were subjected to a species-specific PCR assay using the primers pairs C729+/- described by Rigotti et al. (2002) The amplified product (GeneBank accession No. KP141797) was sequenced showing 99% sequence similarity with comparable sequences of B. cinerea from database. The pathogenicity of the fungal isolate was tested by inoculating gladiolus spikes with spore suspension (2.5 x 104 ml-1) from a 10-day-old culture grown on PDA. The plants were kept covered with moistened perforated polyethylene bags for 24 h. Typical disease symptoms appeared on the inoculated spikes on which the development of a grey mycelial growth was also observed. To the best of our knowledge, this is the first report of Botrytis cinerea of gladiolus in India.