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Abstract
Phytophthora taxon Pg chlamydo is perhaps the second most abundant
Phytophthora species in the world, after
P. gonapodyides, although it is commonly misidentified. Pg chlamydo is frequently encountered in streams and rivers in western North America, Argentina, China, and Europe. It has occasionally been recovered from forest soil and was once isolated from a bole canker on a tanoak tree; it was pathogenic to tanoak in artificial inoculation. Pg chlamydo resembles
P. gonapodyides in culture, and is related to that species. It is apparently sterile, not itself forming sexual structures even when paired with tester isolates of known mating type. Sporangia are non-descript nonpapillate, similar to other species in the
P. megasperma/P. gonapodyides ITS clade. It is distinguished from
P. gonapodyides by the formation of chlamydospores in culture. It has also been misidentified as
P. lateralis,
P. drechsleri or P. cryptogea, although the latter species are heterothallic, and readily distinguished with a mating test. ITS-DNA sequences of isolates from Oregon, California, Argentina, and France were identical, but at least three mitochondrial genotypes were distinguished.
Parent Publication
Citation
Hansen, Everett; Reeser, Paul; Sutton, Wendy . 2009. The
Phytophthora species known as "Pg chlamydo". In: Goheen, E.M.; Frankel, S.J., tech. coords. Proceedings of the fourth meeting of the International Union of Forest Research Organizations (IUFRO) Working Party S07.02.09: Phytophthoras in forests and natural ecosystems. Gen. Tech. Rep. PSW-GTR-221. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 284-287.
