First Report of Leaf Spot in Farfugium japonicum Caused by Alternaria tenuissima in Korea

Abstract

Farfugium japonicum (L.) Kitam (common name: Leopard plant) is known as a medical herb and belongs to family Asteraceae (1). In June 2012, a leaf spot disease was observed on the leaf surface of F. japonicum at a forest research plot Jinju, Gyeongnam province, Korea. More than 95% of F. japonicum plants were infected and leaf spot symptom appeared in the regions under our investigation. Light brownish symptoms initially developed and the spot size gradually increased and turned dark brown with an irregular shape as the disease progressed (spot size 1 to 10 mm in diameter). At the late stage of disease, spots became hollow and completely dehydrated. The infected leaves were easily crumbled, possibly due to dryness. To isolate the causal agent, the infected leaves were surface disinfected and pieces of leaves were placed on water agar (WA). Nine isolates were isolated from 10 pieces of the infected leaves. Fungi mycelia from the WA were transferred on potato dextrose agar (PDA) and incubated at 28°C for 7 days. The colonies were purple navy to black and conidia spores developed on the media. The morphological characteristics of spores were multi-septate, dark brown, pyriform, and 6.7 to 12.8 × 22.2 to 38.4 μm. The spores had 1 to 4 transverse and 0 to 3 longitudinal septa. The morphological characteristics of the isolates showed considerably similar to well-known Alternaria tenuissima (2). The leaf spot disease caused by A. cinerariae of F. japonicum was reported from Japan (3). Spores of A. cinerariae are golden brown to brown with 3 to 9 transverse and 0 to 6 longitudinal septa and are 87.5 × 28.7 μm (avg.) (3). To verify pathogenicity of the isolate, the pure cultured fungi on the PDA medium was taken (4 mm in diameter) and placed on healthy leaves of Leopard plant. The artificially inoculated leaves were placed on wet filter paper in Petri dishes and incubated at 25°C and 80% humidity. At 7 days after inoculation, similar disease symptoms developed on 8 out of 10 infected Leopard plant leaves. The pathogen was reisolated from artificially infected leaves. To identify in molecular biology level, genomic DNA was extracted and the ITS-rDNA region was amplified using universal primers ITS1 and ITS4. The amplified PCR product was purified and sequenced (528 bp) with ITS1 and ITS4 primers for both directions and then deposited in GenBank (Accession No. KC415611.1). The BLAST search showed that it matched previously reported A. tenuissima with 100% identity. To the best of our knowledge, this is the first report of Leopard plant leaf spot disease in Korea. References: (1) E. Y. Kim et al. J. Ethnopharmacol. 146:40, 2013. (2) E. G. Simmons. Page 1 in: Alternaria Biology, Plant Diseases and Metabolites. J. Chelchowski and A. Visconti, eds. Elsevier, Amsterdam, 1992. (3) T. Sakoda et al. Res. Bull. Pl. Prot. Japan 46:73, 2010.

Incidence, pathogenicity and diversity of Alternaria spp. associated with alternaria leaf spot of canola (Brassica napus) in Australia

“…All 12 Alternaria spp. ( A. alternata , A. arborescens , A. brassicae , A. conjuncta , A. ethzedia , A. eureka , A. hordeicola , A. infectoria , A. japonica , A. malvae , A. metachromatica and A. tenuissima ) reported in the current study have been associated with alternaria leaf spot either within or outside Australia on one or more Brassicaceae or non‐Brassicaceae hosts (Sampson & Walker, ; Shivas, ; Fisher et al ., ; You et al ., , ; Mułenko et al ., ; Garibaldi et al ., ; Sharma et al ., ; Bassimba et al ., ; Harteveld et al ., ; Lee et al ., ; Bashir et al ., ; Barkat et al ., ; Taj et al ., ; Van de Wouw et al ., ; Atlas of Living Australia, ; APPD, ; Farr & Rossman, ; Moslemi et al ., ; Siciliano et al ., ). It is evident that leaf spotting on canola in Australia is not soley caused by a single widely recognized Alternaria species such as A. brassicae , but that a range of up to nine other Alternaria spp.…”

“…() found that all tested isolates of A. alternata , A. arborescens , A. brassicicola , A. japonica and A. tenuissima were pathogenic across different hosts in the family of Brassicaceae; while Farr & Rossman () reported A. ethzedia on B. napus in Switzerland, A. hordeicola on Hordeum vulgare in Norway and A. malvae on Malva sinensis in China. Furthermore, alternaria leaf spotting caused by A. conjuncta has been recorded on Daucus carota in Poland (Mułenko et al ., ), A. infectoria on Malus domestica in South Africa (Farr & Rossman, ), A. metachromatica on Solanum lycopersicum in Pakistan (Bashir et al ., ), A. tenuissima on Farfugium japonicum in Korea (Lee et al ., ), and Cajanus cajan in India (Sharma et al ., ).…”

“…in SA and A. eureka on Medicago rugosa in VIC; Shivas (1989) reported A. infectoria on Phaseolus vulgaris, Pisum sativum and Sorghum bicolor in WA; Moslemi et al (2017), also reported A. infectoria but on Tanacetum cinerariifolium in Tasmania, while Barkat et al (2016) recorded it on Triticum aestivum seed in NSW, SA, VIC and WA; APPD (2017) reported A. metachromatica on T. aestivum in SA; and both You et al (2005) and Harteveld et al (2013) (Taj et al, 2016). In addition, Siciliano et al (2017) found that all tested isolates of A. alternata, A. arborescens, A. brassicicola, A. japonica and A. tenuissima were pathogenic across different hosts in the family of Brassicaceae; while Farr & Rossman (2017) (Mułenko et al, 2008), A. infectoria on Malus domestica in South Africa (Farr & Rossman, 2017), A. metachromatica on Solanum lycopersicum in Pakistan (Bashir et al, 2014), A. tenuissima on Farfugium japonicum in Korea (Lee et al, 2013), and Cajanus cajan in India (Sharma et al, 2012).…”

Luobuma Leaf Spot Disease Caused by Alternaria tenuissima in China

“…This fungus causes leaf spot disease in Capsicum annuum [42], Paris polyphylla var. chinensis [43], Solanum melongena [44], Farfugium japonicum [45], Triticum turgidum [46], Avicennia marina [47], Psidium guajava [48], and Aronia melanocarpa [32]. Most of the symptoms of A. tenuissima infection include small circular or irregular brown leaf spots all over the foliage.…”