02015nas a2200145 4500008004100000245012800041210006900169300001200238490000700250520150300257100001901760700001301779700001201792856006501804 2006 eng d00aThe possible origin and relation of Phytophthora katsurae and P. heveae, discovered in a protected natural forest in Taiwan0 apossible origin and relation of Phytophthora katsurae and P heve a273-2770 v473 aWhen a total of 531 soil samples collected from 1976 to 2000 from various locations distributed in every county on the island of Taiwan was assayed, sixteen isolates of Phytophthora katsurae and nine isolates of P. heveae were recovered from three and four counties, respectively. Phytophthora katsurae and P. heveae were isolated from a protected natural forest located atop a hill at Lenhuachih without higher land within the range of vision, suggesting that both species are indigenous to Taiwan. Phytophthora katsurae is distinguished from the similar P. heveae by its verrucose oogonial wall. The number of protrusions produced by the Taiwanese isolates of P. katsurae varied greatly ranging from 2 to 23 per oogonium, indicating the unsteadiness of this taxonomical characteristic. Oogonia produced by isolates of P. katsurae obtained from Hawaii contained very few protrusions. Moreover, most oogonia produced by two of these isolates did not have any protrusions and were indistinguishable from those produced by P. heveae. Results suggest the development of P. heveae directly from P. katsurae by loss of oogonial protrusions. The high level of ITS sequence similarity between P. heveae and P. katsurae in comparison with their relationships to other Phytophthora species tested also support the possibility of the recent development of one species from the other species.1 aWen-Hsiung, KO1 aWang, SY1 aAnn, PJ uhttp://ejournal.sinica.edu.tw/bbas/content/2006/3/Bot473-07/