Cytogenetic evidences on the evolutionary relationships between the tetraploids of the section rhizomatosae and related diploid species (arachis, leguminosae)

• Autores: Ortíz, Alejandra Marcela; Robledo Dobladez, Germán Ariel; Seijo, José Guillermo; Montenegro Valls, José Francisco; Lavia, Graciela Inés
• Año de publicación: 2017
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Journal of Plant Research, 2017, vol. 130, no. 5, p. 791-807.
• Materia: Arachis; Evolutionary relationships; Heterochromatin; Karyotype; Rhizomatosae; rDNA loci
• Institución: Universidad Nacional del Nordeste

Fil: Ortíz, Alejandra Marcela. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Ortíz, Alejandra Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina.
Fil: Robledo Dobladez, Germán Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina.
Fil: Seijo, José Guillermo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Seijo, José Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina.
Fil: Montenegro Valls, José Francisco. Embrapa Genetic Resources and Biotechnology; Brasil.
Fil: Lavia, Graciela Inés. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura; Argentina.
Fil: Lavia, Graciela Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica del Nordeste; Argentina.
Rhizomatosae is a taxonomic section of the South American genus Arachis, whose diagnostic character is the presence of rhizomes in all its species. This section is of particular evolutionary interest because it has three polyploid (A. pseudovillosa, A. nitida and A. glabrata, 2n = 4x = 40) and only one diploid (A. burkartii, 2n = 2x = 20) species. The phylogenetic relationships of these species as well as the polyploidy nature and the origin of the tetraploids are still controversial. The present study provides an exhaustive analysis of the karyotypes of all rhizomatous species and six closely related diploid species of the sections Erectoides and Procumbentes by cytogenetic mapping of DAPI/CMA heterochromatin bands and 5S and 18-26S rDNA loci. Chromosome banding showed variation in the DAPI heterochromatin distribution pattern, which, together with the number and distribution of rDNA loci, allowed the characterization of all species studied here. The bulk of chromosomal markers suggest that the three rhizomatous tetraploid species constitute a natural group and may have at least one common diploid ancestor. The cytogenetic data of the diploid species analyzed evidenced that the only rhizomatous diploid species-A. burkartii-has a karyotype pattern different from those of the rhizomatous tetraploids, showing that it is not likely the genome donor of the tetraploids and the non-monophyletic nature of the section Rhizomatosae. Thus, the tetraploid species should be excluded from the R genome, which should remain exclusively for A. burkartii. Instead, the karyotype features of these tetraploids are compatible with those of different species of the sections Erectoides and Procumbentes (E genome species), suggesting the hypothesis of multiple origins of these tetraploids. In addition, the polyploid nature and the group of diploid species closer to the tetraploids are discussed.