Variants of Phytophthora Cinnamomi Extend the Known Limits of the Species

ABSTRACT

The morphological and physiological characteristics of Phytophthora cinnamomi isolates including two from citrus and one each from soil, pineapple, and avocado from Taiwan, one from camellia from California, and one from macadamia from Hawaii, were studied. Only PCiC1 and PCiC11 from citrus made slight growth at 36 C and failed to produce chlamydospores in any media tested. The average length: breadth ratio of sporangia was 1.5-1.8 for all isolates except for PCiC1 which produced nearly spherical sporangia with the average length: breadth ratio of 1.2. Only PT6 from soil was capable of producing sporangia on 5% V-8 agar. Both PCiC1 and PCiC11 are A¹ mating type and belong to sexuality type 2. PT5, the avocado PCiA, and the macadamia 64F are A² mating type belonging to sexuality type 4. The pineapple PCiP, and the camellia PC97 are A¹ mating type belonging to sexuality type 1. All of these fungi have identical protein patterns.

Key Words:

• Phytophthora cinnamomi
• variant
• species concept
• Taiwan