Phytophthora hydropathica, a new pathogen identified from irrigation water, Rhododendron catawbiense and Kalmia latifolia

Abstract

A new species of Phytophthora, previously referred to as taxon Dre II, is named Phytophthora hydropathica. It is heterothallic, but all isolates recovered to date are of the A1 compatibility type. Plerotic oospores are produced. Its sporangia are usually obpyriform and are nonpapillate and noncaducous. Isolates of P. hydropathica had nearly identical single-strand conformation polymorphism (SSCP)-based DNA fingerprints that are distinct from those of all existing species. Their closest relatives are P. parsiana and P. irrigata. This new species is able to grow at relatively high temperatures, with an optimum of 30°C and a maximum of 40°C. It was frequently isolated from irrigation water during warm summers. This species caused leaf necrosis and shoot blight of Rhododendron catawbiense and collar rot of Kalmia latifolia at two nurseries where irrigation reservoirs yielded P. hydropathica. Its potential impact on other horticultural crops is discussed.

Phytophthora hydropathica y Phytophthora drechsleri aisladas de canales de irrigación del Valle de Culiacán

“…These morphological characteristics coincide with those for the species Phytophthora hydropathica described in the key proposed by Martin et al (2012), as well as the description by Hong et al (2010). It is worth mentioning that these two descriptions of P. hydropathica mention that the species Phytophthora parsiana presents very similar morphological characteristics.…”

Fishing for Phytophthora from Western Australia’s waterways: a distribution and diversity survey

“…Several new species have recently been described from ITS Clade 9 from irrigation water (Hong et al 2008(Hong et al , 2010, however, the pathogenicity of these species is unknown and they may fill a similar ecological niche to that proposed for Clade 6 with a predominance in native riparian, forest and woody ecosystems (Brasier et al 2003a;Jung et al 2011;Nechwatal et al 2012). Davison et al (2005) had previously isolated P. cinnamomi var.…”

A unique species in Phytophthora clade 10, Phytophthora intercalaris sp. nov., recovered from stream and irrigation water in the eastern USA

“…Approximately 80 novel species of Phytophthora have been described since 2000, with 16 of these novel species (plus many provisional species) first recovered from aquatic ecosystems. Specifically, these include P. amnicola (Crous et al, 2012), P. borealis (Hansen et al, 2012), Phytophthora chlamydospora (5Phytophthora taxon Pgchlamydo) (Brasier et al, 2003;Hansen et al, 2015), P. fluvialis (Crous et al, 2011), P. lacustris (Nechwatal et al, 2013), P. moyootj (Crous et al, 2014) and Phytophthora taxon aquatilis (Hong et al, 2012) from stream water, Phytophthora aquimorbida (Hong et al, 2012), P. hydrogena (Yang et al, 2014b), Phytophthora hydropathica (Hong et al, 2010), P. macilentosa (Yang et al, 2014a), P. mississippiae , P. stricta (Yang et al, 2014a) and P. virginiana ) from irrigation water and Phytophthora pluvialis (Reeser et al, 2013) from canopy drip. These species, along with Phytophthora gonapodyides, exemplify endemic and dominant species in aquatic environments worldwide, while their less-frequent presence in terrestrial environments indicates the potential variation in composition of species of Phytophthora between aquatic and terrestrial habitats.…”