Heterokaryon Formation from Color and Nutrient Mutants Resistant to Chlorate and Selenite in Fungus Alternaria alternate

Abstract

The frequency of spontaneous mutants resistant to both chlorate and selenite was compared with the frequency of mutations induced by ultraviolet rays. The results showed that, the frequencies of chlorate resistance strains which isolated from two different parenting strains, AA 1 and SW 1 , were higher than 27 and 23 times from spontaneous frequencies respectively, so as for selenite resistant results, the induced and isolating mutants of two different parenting strains, AA 1 and SW 3 , were about 5 and 8 times higher than their spontaneous frequency, respectively. The mutant strains (Chl 5-Ch l9) and (Chl 13-Chl 27) were all resistant to chlorate-nitrate auxotrophic but they were distributed between spontaneous and induced as well as white or black conidia, while the mutants sel 1-sel 5 resistance to the selenite are color mutants (white conidia) and sulfates auxotrophic at the same time. Heterokaryon was also formed in Alternaria alternata between the two black Chl 10 strains, nitrate auxotrophic, have the genotype (nit 10 , w 2 + , s 2 +) and the white Sel2