biologia plantarum

Biologia plantarum 24:415-422, 1982 | DOI: 10.1007/BF02880437

The effect ofN-nitroso-N-ethylurea on mutagenesis ofCercospora beticola SACC

Dorota Brilová¹

¹ Institute of Experimental Phytopathology and Enthomology, Slovak Academy of Sciences, Ivanka pri Dunaji, Czechoslovakia

Lethal and mutagenic effects ofN-nitroso-N-ethylurea (NEU) on the parasitic fungusCercospora beticola Sacc. was investigated. Mutation frequency increased and the number of surviving individuals (conidia) simultaneously decreased with increasing mutagen concentration and the period of its application.
Treatment ofC. beticola conidia with NEU induced 14 morphological mutants characterized by changes in pigmentation of air mycelium and substrate, excretion of the pigment into the cultivation medium and colonies morphology. A considerable proportion of morphological mutants lost their sporulation ability bothin vitro on the sporulation medium andin vivo on host leaves and became non-pathogenic. The other morphological mutants (21.4%) were pathogenic on a sensitive sugar beet cultivar Dobrovická A and on other three resistant cultivars (Maribo 1, 2, 3).
A revertant with increased pathogenity arose from the light non-pathogenic mutant. During the remonosporic isolation of the pathogenic mutants isolates were obtained characterized by a phenotype which originated during the mutagenic process.

Received: May 12, 1981; Accepted: November 30, 1981; Published: November 1, 1982  Show citation