Occurrence of the rare A2 mating type of Phytophthora infestans on imported Egyptian potatoes and the production of sexual progeny with A1 mating types from the UK

Phytophthora infestans from blighted potato tubers imported from Egypt and on sale to the public in North Wales were all of the A2 mating type which was thought, until recently, to be confined to Mexico, Zygotes from Welsh and Egyptian matings germinated readily; progeny were variable. The threat posed by a general spread of the A2 mating type is discussed.

[1]  D. Erwin,et al.  Genetic Recombination in Germinated Oospores of Phytophthora infestans , 1967, Nature.

[2]  W. Ko.  Heterothallic Phytophthora : Evidence for Hormonal Regulation of Sexual Reproduction , 1978 .

[3]  E. Sansome.  Polyploidy and Induced Gametangial Formation in British Isolates of Phytophthora infestans , 1977 .

[4]  W. Black.  III.—A Genetical Basis for the Classification of Strains of Phytophthora infestans , 1953 .

[5]  E. Sansome.  Cytological studies on Phytophthora nicotianae var. parasitica in relation to mating type , 1985 .

[6]  D. S. Shaw,et al.  Oospores in cultures of Phytophthora infestans resulting from selfing induced by the presence of P. drechsleri isolated from blighted potato foliage , 1984 .

[7]  J. Jinks,et al.  Spontaneous variability of single isolates of Phytophthora infestans. I. Cultural variation , 1968 .

[8]  P. H. Tsao,et al.  Formation of sex organs in the A1 mating type of Phytophthora infestans induced chemically by A2 isolates of other species of Phytophthora , 1983 .

[9]  M. E. Gallegly,et al.  Genetic Recombination and Mode of Inheritance of Pathogenic Characters by Phytophthora infestans Through Sexual Reproduction , 1983 .

[10]  J. Niederhauser.  DIVISION OF MYCOLOGY: THE BLIGHT, THE BLIGHTER, AND THE BLIGHTED* , 1956 .

[11]  WORTHINGTON G. Smith.  The Resting-Spores of the Potato Fungus , 1875, Nature.

[12]  H. Hohl,et al.  Strains of Phytophthora infestans from Switzerland with A2 mating type behaviour , 1984 .

[13]  E. Sansome.  Reciprocal translocation heterozygosity in heterothallic species of Phytophthora and its significance , 1980 .

[14]  A. Campbell,et al.  Production of oospores in vitro by self fertilization in single isolates of A1 mating types of Phytophthora infestans , 1985 .