title: Vegetative compatibility groups and parasexual segregation in Colletotrichum acutatum isolates infecting different hosts.
abstract: Heterokaryosis is an important mechanism which provides genetic variability increase in filamentous fungi. In order to assess the diversity of vegetative compatibility reactions existing among Colletotrichum acutatum isolates derived from different hosts, complementary nit mutants of each isolate were obtained and paired in all possible combinations. Vegetative compatibility groups (VCG) were identified among the isolates according to their ability to form viable heterokaryons. Seven VCGs were identified among the isolates, one of which contained isolates from different hosts. VCGs 2 and 6 contained two and three members, respectively; VCG-3 contained four members, and four VCGs (1, 4, 5, and 7) contained a single one. This study shows, for the first time, the isolation and the parasexual segregation of a heterozygous diploid sector derived from the heterokaryon formed with nit mutants from VCG-6. Diploid, named DE-3, showed nit+ phenotype and growth rate similar to the parental wild isolate. When inoculated in the presence of the haploidizing agent benomyl, the diploid strain produced parasexual haploid segregants exhibiting the nit phenotypes of the crossed mutants. Since viable heterokaryons and diploid may be formed among vegetative compatible isolates of C. acutatum, this study suggests that the parasexual cycle may be an alternative source of genetic variability in C. acutatum isolates.
authors.affiliation: Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR Brazil.
authors.forename: Claudinéia Conationi
authors.initials: CC
authors.lastname: da Silva Franco
authors.forename: Juliane Rocha
authors.initials: JR
authors.lastname: de Sant' Anna
authors.forename: Lúcia Jacovozzi
authors.initials: LJ
authors.lastname: Rosada
authors.forename: Edilson Nobuyoshi
authors.initials: EN
authors.lastname: Kaneshima
authors.forename: José Renato
authors.initials: JR
authors.lastname: Stangarlin
authors.forename: Marialba Avezum Alves
authors.initials: MA
authors.lastname: De Castro-Prado
mesh_terms: D020231:Colletotrichum / Q000145:classification* / Q000235:genetics / Q000502:physiology; D004271:DNA, Fungal / Q000235:genetics; D004171:Diploidy; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000145:classification* / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D013045:Species Specificity
chemical_list: D004271:DNA, Fungal