Vegetative compatibility and parasexual segregation in Colletotrichum lindemuthianum, a fungal pathogen of the common bean

• Published in: Genetics and molecular research Vol. 6; no. 3; pp. 634 - 642
• Main Authors: Castro-Prado, M.A.A, Querol, C.B, Sant'Anna, J.R, Miyamoto, C.T, Franco, C.C.S, Mangolin, C.A, Machado, M.F.P.S
• Format: Journal Article
• Language: English
• Published: Brazil 01-01-2007
• Subjects: Cell Nucleus - metabolism; Chromosome Segregation; Colletotrichum - cytology; Colletotrichum - enzymology; Colletotrichum lindemuthianum; Diploidy; Esterases - metabolism; Haploidy; host plants; Hyphae - cytology; Mutation - genetics; Nitrates - metabolism; Phaseolus - microbiology; Phaseolus vulgaris; Phenotype; plant pathogenic fungi
• ISSN: 1676-5680; 1676-5680

The heterokaryotic and vegetative diploid phases of Colletotrichum lindemuthianum are described using nutritional and biochemical markers. Nitrate non-utilizing mutants (nit), derived from R2047, R89, R73, R65, and R23 isolates, were paired in all possible combinations to obtain heterokaryons. Although pairings R2047/R89, R2047/R73, R65/R73, and R73/R23 showed complete vegetative incompatibility, prototrophic heterokaryons were obtained from pairings R2047/R65, R2047/R23, R65/R89, R65/R23, R73/R89, R89/R23, R2047/R2047, R65/R65, R89/R89, R73/R73, and R23/R23. Heterokaryons gave rise to spontaneous mitotic segregants which carried markers corresponding to one or the other of the parental strains. Heterokaryons spontaneously produced prototrophic fast-growing sectors too, characterized as diploid segregants. Diploids would be expected to yield auxotrophic segregants following haploidization in basal medium or in the presence of benomyl. Parental haploid segregants were in fact recovered from diploid colonies growing in basal medium and basal medium containing the haploidizing agent. Although barriers to the formation of heterokaryons in some crosses were detected, the results demonstrate the occurrence of parasexuality among vegetative compatible mutants of C. lindemuthianum.