title: Vegetative compatibility and anastomosis formation within and among individual germlings of tropical isolates of arbuscular mycorrhizal fungi (Glomeromycota).
abstract: Hyphal anastomoses which play a key role in the formation of interconnected mycorrhizal networks and in genetic exchange among compatible individuals have been studied in a limited number of species and isolates of arbuscular mycorrhizal fungi (AMF), mainly in symbiotic mycelium. In this work, the occurrence and frequency of anastomosis between hyphae of the same and different germlings were assessed in tropical isolates belonging to Acaulospora, Claroideoglomus, Gigaspora, Glomus, Rhizophagus and Scutellospora. Germlings belonging to Acaulospora, Claroideoglomus, Glomus and Rhizophagus formed perfect hyphal fusions, with frequencies ranging from 9.29 ± 3.01 to 79.84 ± 4.39 % within the same germling and from 14.02 ± 7.36 to 91.41 ± 3.92 % between different germlings. Rare fusions, occurring within the same hypha, were detected in Gigaspora species, and no anastomoses were observed in Scutellospora species. The consistent detection of nuclei in perfect fusions suggests that nuclear migration is active both within and between germlings. Present data on anastomosis formation, nuclear migration and germling viability in tropical isolates of AMF widen our knowledge on the extensive and consistent occurrence of successful hyphal fusions in this group of beneficial symbionts. The ability to anastomose and establish protoplasm flow, fundamental for the maintenance of physiological and genetic continuity, may produce important fitness consequences for the obligately biotrophic AMF.
authors: DCS-Laboratório de Microbiologia do Solo, Universidade Federal de Lavras, Caixa Postal 3037, CEP 37200-000, Lavras, Minas Gerais, Brazil. candidobnn@yahoo.com.br
authors: Cândido Barreto
authors: CB
authors: de Novais
authors: Cristiana
authors: C
authors: Sbrana
authors: Orivaldo José
authors: OJ
authors: Saggin Júnior
authors: José Oswaldo
authors: JO
authors: Siqueira
authors: Manuela
authors: M
authors: Giovannetti
mesh_terms: D055137:Glomeromycota / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D025301:Hyphae / Q000145:classification / Q000235:genetics / Q000254:growth & development; D038821:Mycorrhizae / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D012988:Soil Microbiology; D013172:Spores, Fungal / Q000145:classification / Q000235:genetics / Q000254:growth & development; D014329:Tropical Climate