FIRST REPORT OF A GRAY MOLD ON LILIUM CERNUUM KOMAR.

Abstract

Lilium cernuum Komar. a rare Lilium purple species, is a perennial herb, low in height and fragrant, pale purple-red tepals, with deep purple spots toward base (Wang and Tang, 1980). In September 2012, gray mold symptoms were seen for the first time in Benxi City. In August 2013, the disease had spread up to Liaoning Province. Symptoms initially appeared as yellowish brown to reddish-brown water-soaked spots which enlarged and developed into oval, round or large irregular spots, with identifiable borders. For pathogen identification, leaf pieces (3 to 5 mm) including both symptomatic and healthy tissue, were surface-disinfected in 75% ethanol for 5 s, and in 0.1% aqueous mercuric chloride for 1 min,,rinsed with sterilized water three times, and incubated on potato dextrose agar at 25°C for 14 days in darkness. Single spore isolates were obtained from individual conidia. Isolates grown on synthetic nutrient agar in slide cultures, produced hyphae clusters, straight and dark gray with a few branches and separating membranes of 20-25 µm, and colorless conidia, circular or elliptical, nearly obtuse or slightly tipped at the top, 10-15 µm × 5-10 µm in size. Conidiophores germinated in one or two ends or intermediately with more slender germ tubes. Based on morphological characterization the fungus was tentatively identified as B. cinerea (Coley-Smith et al., 1980). For molecular identification, internal transcribed spacer region was amplified by PCR using ITS1 and ITS4 primers and sequenced (GenBank accession No. KU951145), The sequence showed 100% similarity with an undescribed B. cinerea species isolated from deep sea fungi in Xiamen, Fujian, China (KP003819). To fulfill Koch's postulates, eight 1-year-old seedlings were inoculated with conidial suspensions (107 conidia ml-1 ) and incubated under moist conditions for 3 to 4 days at 25°C. All leaf spots developed on inoculated leaves were similar to those observed in the field. B.cinerea was recovered from the lesions and its identity was confirmed by morphological and molecular analyses. To the best of our knowledge, this is the first confirmed report of B.cinerea in Lilium cernuum Komar. in China, causing a disease with economical impact.