Class III endophytes, clandestine movement amongst hosts and habitats and their potential for disease; a focus on Neofusicoccum australe

Abstract

Neofusicoccum australe is a class III endophyte characterised by a quiescent passive life phase and an active pathogenic life phase as a latent pathogen. The latter life stage has been observed worldwide for numerous woody horticultural hosts. In this study, we have re-evaluated GenBank ITSrDNA sequence data to establish the current host and geographical range of N. australe. Additionally, we have interrogated the diversity of N. australe in Australia using microsatellite markers to ascertain if there are any host or site preference for different genotypes. N. australe has a widespread distribution across ten countries and colonises 46 hosts from 18 plant families; mainly angiosperms, some coniferous species and one monocot. Phylogenetic analysis of the ITSrDNA sequence indicates there is a single dominant ITS genotype present in most locations and there are another 12 rare or moderately rare genotypes. Populations of N. australe in Australia appear to be highly diverse, and there is no discernable host or habitat restriction. The dominance of N. australe in native forest throughout the southwest of Western Australia, and its rarity elsewhere in native vegetation, while being common as a pathogen of horticultural hosts, suggests that this species is endemic to Western Australia.