Phytophthora chlamydospora

Abstract

Phytophthora chlamydospora Brasier and Hansen is found in streams and wet soil worldwide and is a pathogen of some riparian tree species as well as horticulturally valuable fruit and nut trees and nursery stock. It is self-sterile, and produces persistent non-papillate sporangia, usually on unbranched sporangiophores. Chlamydospores are formed most regularly at warmer temperatures. First isolated in 1971 from waterlogged roots of an ornamental Prunus in Gloucestershire, UK, it was tentatively assigned to P. gonapodyides Petersen (Buisman). Similar isolates from Britain and North America were collected and subsequently compared using DNA-based approaches. The UK Prunus isolate and some isolates from nurseries in Oregon and Washington, USA produced large thin-walled chlamydospores in culture and were considered to represent a separate taxon from the nonchlamydospore-forming P. gonapodyides (Brasier et al. 1993). The chlamydospore-forming group was informally designated Phytophthora taxon Pgchlamydo. P. chlamydospora sp. nov., was formally named in 2015 (Hansen et al. 2015). Etymology: "Chlamydospora" refers to the distinguishing chlamydospores formed especially at higher temperatures. The earlier informal name of "taxon Pgchlamydo" recalls its similarity in culture and habitat to P. gonapodyides. Phytophthora chlamydospora Morphology Chlamydospores formed in agar media may be scarce at 22° C but are usually abundant at 28° C. Chlamydospores are mostly intercalary but lateral, terminal and sessile chlamydospores are also observed (Figures 1 a,b,c). Clumps of large globose to subglobose hyphal swellings in branched chains are usually formed in water (Figure 1 d).

Phytophthora austrocedri in Argentina and Co-Inhabiting Phytophthoras: Roles of Anthropogenic and Abiotic Factors in Species Distribution and Diversity

“…However, despite its abundance in streams, there is generally no evidence of disease in the surrounding vegetation in the study area. In contrast, P. chlamydospora appears to be a pathogen of woody plants and horticulturally valuable species [77], which could have implications for site 1. The other species found in clade 6b of the phylogeny of Yang et al [22] (P. gonapodyides, P. mississipiae, P. bilorbang, P. megasperma) were associated with heavy wet soils or samples taken next to streams.…”

Caracterización de <i>Phytophthora capsici</i> como patógeno de especies hortícolas presentes en la zona noreste de la provincia de Buenos Aires

“…como el agente causal de la mortalidad extensiva de forestaciones de Port-Orfordcedar (Chamaecyparis lawsoniana) o "cedro" de Oregón en la región Oeste de Estados Unidos (Erwin & Ribeiro, 1996;Hansen, 2000). Otros reportes a nivel mundial incluyen a forestaciones en Taiwán (Brasier et al, 2010) y Europa (Robin et al, 2011).…”

“…En los bosques andino-patagónicos, la mortandad del ciprés de la cordillera (Austrocedrus chilensis), fue asociada principalmente a P. austrocedrae Greslebin & Hansen (Greslebin et al, 2005), constituyendo una nueva especie. Los síntomas que produce este patógeno mostraron características similares a los ocasionados por otros taxones de Phytophthora, tal como P. lateralis (Hansen 2000;Greslebin et al, 2007). P. nicotianae fue identificada en una amplia variedad de especies vegetales, desde ornamentales (Wolcan & Grego, 2004), frutales (Canteros, 2009), forestales y hortícolas en Córdoba (Frezzi, 1950) y hortícolas en Buenos Aires (Iribarren et al, 2012).…”