Genetics of Phytopathogenic Fungi: Ix. Heterocaryosis and the Parasexual Cycle in Penicillium Italicum and Penicillium Digitatum

Abstract

Ten nutritionally deficient strains of Penicillium italicum with mutant colors were involved in 13 heterocaryons. Three heterocaryons yielded diploid strains. Not all possible genotypes were present among the segregants from the diploids. One case of presumptive linkage was detected. Seven nutritionally deficient strains of P. digitatum with mutant colors were involved in five combinations to obtain heterocaryons. Heterocaryosis could not be definitely demonstrated in this species.

The Parasexual Cycle and Linkage Groups in Penicillium Expansum

“…LEWIS and BARRON (1964), studying the parasexual cycle in Aspergillus amstelodami, point out that double auxotrophic segregants appear less frequently than anticipated in relation to single auxotrophic segregants. Deviating segregation ratios were also indicated in the study of the parasexual cycle of Penicillium italicum by STRUMNAB, GARBER and BERAHA (1964).…”

Isolation of recombinant strains with enhanced pectinase production by protoplast fusion between Penicillium expansum and Penicillium griseoroseum

“…The spontaneous parasexual cycle in the Penicillium genus has been described for the species P. chrysogenum (30), P. expansum (8), P. italicum and P. digitatum (39), and P. roqueforti (15), while the induced parasexual cycle in P. griseoroseum was described by Santos (37). Fusions of interspecific protoplasts were obtained between P. chrysogenum and P. notatum (3) and between P. chrysogenum and P. roqueforti (4).…”

Genetics of ergoline alkaloid formation in Penicillium roquefortii

“…Although the parasexual cycle has not yet been demonstrated in P. roquefortii, there are many species of Penicillium in which the parasexual cycle has been demonstrated (5,12,17). Also, heterokaryon formation, an important first step in the parasexual cycle, has been obtained through the protoplast fusion technique in P. roquefortii (4).…”