Taxonomy and DNA phylogeny of Diatrypaceae associated with Vitis vinifera and other woody plants in Australia

Abstract

The Diatrypaceae occur worldwide and comprise a number of pathogens of woody crops, forest and ornamental tree species. Despite the taxonomic difficulties within this family, interest in the Diatrypaceae has increased recently, mainly due to the recent detection of these fungi in the premium grape growing regions of California. In the present study, we investigated the diversity and host range of diatrypaceous fungi from prominent wine grape growing regions in South Australia, New South Wales and Western Australia. Approximately 100 isolates were collected from grapevine and other woody plants and compared with reference collections from the United States and Europe. Phylogenetic analyses of the complete sequence of the internal transcribed spacer (ITS) region of the ribosomal DNA and partial sequence of the β-tubulin gene, combined with morphological analyses separated 12 species. These included the previously described species Cryptovalsa ampelina, C. rabenhorstii, Diatrype brunneospora, Eutypa lata, E. leptoplaca, Eutypella australiensis, E. citricola, a Cryptosphaeria sp. and a Diatrype sp., whereas Diatrypella vulgaris, Eutypella cryptovalsoidea and E. microtheca are described as new. Seven species were isolated from grapevine but the prevalence of Diatrypaceae in grapevine cankers varied among the regions surveyed. In many instances in WA and NSW, these newly reported fungi were more widespread and abundant than E. lata. This study provides new information to assist with diagnosis of the causal agents of dieback and canker diseases in Australia and development of management strategies. Further studies to characterize the pathogenicity of diatrypaceous species to grapevines and to elucidate the biology of these fungi are underway.