Current status of Phytophthora in Australia 2021
Among the most economically relevant and environmentally devastating diseases globally are those caused by Phytophthora species. In Australia, production losses in agriculture and forestry result from several well-known cosmopolitan Phytophthora species and infestation of natural ecosystems by Phytophthora cinnamomi have caused irretrievable loss to biodiversity, especially in proteaceous dominated heathlands. For this review, all available records of Phytophthora in Australia were collated and curated, resulting in a database of almost 7869 records, of which 2957 have associated molecular data. Australian databases hold records for 99 species, of which 19 are undescribed. Eight species have no records linked to molecular data, and their presence in Australia is considered doubtful. The 99 species reside in 10 of the 12 clades recognised within the complete phylogeny of Phytophthora. The review includes a discussion on each of these species' status and additional information provided for another 29 species of concern. The first species reported in Australia in 1900 was Phytophthora infestans. By 2000, 27 species were known, predominantly from agriculture. The significant increase in species reported in the subsequent 20 years has coincided with extensive surveys in natural ecosystems coupled with molecular taxonomy and the recognition of numerous new phylogenetically distinct but morphologically similar species. Routine and targeted surveys within Australian natural ecosystems have resulted in the description of 27 species since 2009. Due to the new species descriptions over the last 20 years, many older records have been reclassified based on molecular identification. The distribution of records is skewed toward regions with considerable activity in high productivity agriculture, horticulture and forestry, and native vegetation at risk from P. cinnamomi. Native and exotic hosts of different Phytophthora species are found throughout the phylogeny; however, species from clades 1, 7, and 8 are more likely to be associated with exotic hosts. The database compiled here for Australia and the information provided for each species overcomes this challenge. This review will aid federal and state governments in risk assessments and trade negotiations by providing a comprehensive resource on the current status of Phytophthora species in Australia. Three excel files are provided. 1. all Phytophthora records for Australia with details on host, location, year collected, collector and links to molecular data. 2. a list of all Phytophthora species in Australia, the year they were described and they were first reported in Australia 3. ITS sequence data for several Phytophthora species downloaded from Genbank list the species name given on Genbank and the species identity as determined by phylogenetic alaysis
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Records of Phytophthora in Australia were obtained from various sources including Australian Plant Pest Database, various state herbaria and collections, private and collections. Molecular data were obtained predominately from Genbank, but also from private collections. Once compiled in Excel and data formatted to the same style, accessions from the different sources were cross-referenced and duplicates removed where possible, retaining the different collection codes with each isolate. The data collection, while exhaustive, may not include records from private collections or from government departments where records have not been digitised or made publicly available. A record was considered unsubstantiated if no supporting molecular data was available.