Current and projected global distribution of Phytophthora cinnamomi, one of the world's worst plant pathogens

Abstract

Accepted ArticleThis article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/gcb.13492 This article is protected by copyright. All rights reserved. Accepted ArticleThis article is protected by copyright. All rights reserved. AbstractGlobally, Phytophthora cinnamomi is listed as one of the 100 worst invasive alien species and active management is required to reduce impact and prevent spread in both horticulture and natural ecosystems. Conversely, there are regions thought to be suitable for the pathogen where no disease is observed. We developed a CLIMEX model for the global distribution of P. cinnamomi based on the pathogen's response to temperature and moisture and by incorporating extensive empirical evidence on the presence and absence of the pathogen. The CLIMEX model captured areas of climatic suitability where P. cinnamomi occurs that is congruent with all available records. The model was validated by the collection of soil samples from asymptomatic vegetation in areas projected to be suitable by the model for which there were few records. DNA was extracted and the presence or absence of P. cinnamomi determined by high throughput sequencing (HTS). While not detected using traditional isolation methods, HTS detected P. cinnamomi at higher elevations in eastern Australia and central Tasmania as projected by the CLIMEX model. Further support for the CLIMEX model was obtained by using the large dataset from southwest Australia where the proportion of positive records in an area is related to the Ecoclimatic Index value for the same area. We provide for the first time a comprehensive global map of the current P. cinnamomi distribution, an improved CLIMEX model of the distribution, and a projection to 2080 of the distribution with predicted climate change. This information provides the basis for more detailed regional scale modelling and supports risk assessment for governments to plan management of this important soil-borne plant pathogen.

Predictors of Phytophthora diversity and community composition in natural areas across diverse Australian ecoregions

“…There was a clear role for rainfall influencing community composition as precipitation gradients in both the warmest and wettest months were consistently the most important. However, in this climate the wet and comparably warm winters are very favourable for infection and the pathogen survives the dry summers within its host (Desprez-Loustau et al 2006, Burgess et al 2017a). The importance of these variables is perhaps not surprising given the unique life history of the group.…”

“…However, new techniques for identification are available based on the sampling of environmental DNA and metabarcoding through the use of high throughput sequencing (Català et al 2015). The soil samples were collected from natural ecosystems in regions predicted to be suitable for the growth of Phytophthora cinnamomi (Burgess et al 2017a). The soil samples were collected from natural ecosystems in regions predicted to be suitable for the growth of Phytophthora cinnamomi (Burgess et al 2017a).…”

“…Phytophthora cinnamomi has long been recognised in Australia (Burgess et al 2017a), but P. multivora is a recently described species, previously mis-identified as P. citricola (Scott et al 2009). Phytophthora cinnamomi has long been recognised in Australia (Burgess et al 2017a), but P. multivora is a recently described species, previously mis-identified as P. citricola (Scott et al 2009).…”

High-Throughput Chemical Screening Identifies Compounds that Inhibit Different Stages of the Phytophthora agathidicida and Phytophthora cinnamomi Life Cycles

“…Globally, its principal food crop hosts are avocado and pineapple, but it is also an important pathogen of ecologically significant native plants throughout the temperate regions of the world. Some of the greatest plant losses are in areas with a Mediterranean climate including parts of the United States, Australia, Mexico, and the Iberian Peninsula (Burgess et al, 2017). It also infects a range of ornamental trees and shrubs and is readily spread through the movement and out-planting of nursery stock (Erwin and Ribeiro, 1996).…”

Tree invasions and biosecurity: eco-evolutionary dynamics of hitchhiking fungi

“…For example, in Australia, Phytophthora cinnamomi is the most devastating introduced pathogen and a key threat to the biodiversity of the megadiverse vegetation in the south-west botanical hotspot (Davison and Shearer 1989). This pathogen was accidentally introduced into Australia on tolerant or asymptomatic hosts used to establish orchards (Zentmyer 1985) and its global distribution has probably followed the same pattern (Burgess et al 2016). …”