Dudits D. - Farkas G. L. - Maliga P. (szerk.): Cell genetics in higher plants. Proceedings of an International training course. 5-17 July, 1976, Szeged (Budapest, 1976)
Symposium
Cell Genetics in Higher Plants, 1976 Eds: D. Dudits, G. L. Farkas and P. Maliga SOME CHARACTERISTICS OF INTRA- AND INTERSPECIFIC PROTOPLAST FUSION PRODUCTS OF ASPERGILLUS NIDULANS AND ASPERGILLUS FUMIGATUS L. FERENCZY Department of Microbiology, József Attila University, Szeged Hungary It was previously reported that both intraspecific and interspecific protoplast fusion and nutritional complementa-1-3 tion can be achieved in Aspergilli . The present paper describes recent results concerning protoplast fusion within and between species in Aspergillus /A./ nidulans and A. fumigatus, with the intention of making comparisons between the nature of the intraspecific and interspecific fusion products. Nutritionally-deficient stable mutants were produced 4 from A. nidulans deficient for p-aminobenzoic acid /PABA/ and A. fumigatus /wild-type/. Auxotrophic mutants requiring lysine /lys / and adenine /ade / were used throughout. * The mutants were maintained on yeast-extract-glucose-agar medium and regularly checked for back-mutation on minimal medium consisting of glucose, mineral salts, vitamins and agar. With the mutant strains employed, back-mutation has never been observed. Nutritional complementation of protoplasts of lys and ade mutants, indicated by cell-wall regeneration and growth into complemented colonies /"fusion product"/, was accepted as evidence of protoplast fusion. The methods of cultivation of the mutant pairs on cellophane sheets, the procedure of protoplast formation, protoplast fusion with polyethylene glycol MW 4000 /PEG/, and re-2 3generation were very similar to those described previously ' . The complementation frequency is expressed as the number 171