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A new anthracnose disease of pyrethrum caused by Colletotrichum tanaceti sp. nov
journal contributionposted on 2023-05-17, 17:14 authored by Barimani, M, Pethybridge, SJ, Vaghefi, N, Hay, FS, Taylor, PWJ
A new pathogen of pyrethrum (Tanacetum cinerariifolium) causing anthracnose was described as Colletotrichum tanaceti based on morphological characteristics and a four-gene phylogeny consisting of rDNA-ITS, β-tubulin (TUB2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and actin (ACT) gene sequences. The fungus produced perithecia in culture, requiring an opposite mating type isolate in a heterothallic manner. The initial infection strategy on pyrethrum leaves involved the formation of appressoria followed by production of multilobed infection vesicles in the epidermal cells. Infection and colonization then proceeded through thinner secondary hyphae, which resulted in the initial production of water-soaked lesions followed by black necrotic lesions. The infection process was suggestive of a hemibiotrophic infection strategy. Moreover, phylogenetic analysis clearly showed that C. destructivum, C. higginsianum and C. panacicola were separate species that also had similar intracellular hemibiotrophic infection strategies as C. tanaceti, which all clustered in the C. destructivum complex. Colletotrichum spp. were detected at 1% incidence in seed of 1 of 19 seed lines, indicating the potential for seed as a source of inoculum into crops. Colletotrichum tanaceti was detected in leaf lesions from 11 of 24 pyrethrum fields surveyed between April and July 2012, at a frequency of 1·3-25·0% of lesions. Anthracnose probably contributes to the complex of foliar diseases reducing green leaf area in pyrethrum fields in Australia.
Publication titlePlant Pathology
Department/SchoolTasmanian Institute of Agriculture (TIA)
PublisherWiley-Blackwell Publishing Ltd.
Place of publicationChichester, West Sussex, PO19 8SQ UK
Rights statementCopyright 2013 British Society for Plant Pathology