Emerging oomycete threats to plants and animals

Abstract

Oomycetes, or water moulds, are fungal-like organisms phylogenetically related to algae. They cause devastating diseases in both plants and animals. Here, we describe seven oomycete species that are emerging or re-emerging threats to agriculture, horticulture, aquaculture and natural ecosystems. They include the plant pathogens Phytophthora infestans, Phytophthora palmivora, Phytophthora ramorum, Plasmopara obducens, and the animal pathogens Aphanomyces invadans, Saprolegnia parasitica and Halioticida noduliformans For each species, we describe its pathology, importance and impact, discuss why it is an emerging threat and briefly review current research activities.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.

Keywords: agriculture; disease; environment; food security; parasites; pathogens.

Figure 1.

An emerging clonal lineage reshaped P. infestans populations in Great Britain. (a) Multilocus genotyping of P. infestans isolates from 4000 late blight infection sites over 11 years. This survey revealed that the late blight epidemic that started in 2006 was due to the aggressive 13_A2 isolate that became dominant in only 3 years. The number of surveyed isolates and dominant genotypes of each mating type are indicated. Genotypes with low frequency are grouped as ‘misc’. The shading between bars indicates mating types. (Figure and legend are adapted from Cooke et al. [35].) (b) The 13_A2 isolate has rapidly spread to other continents and caused devastating economic losses especially in developing countries such as India and Egypt [38]. Dots represent an approximate of sampling sites for years 2013 and 2014 according to EuroBlight data and recent reports [39].