INVESTIGADORES
SEIJO Jose Guillermo
artículos
Título:
Species relations among wild Arachis species with the A genome
Autor/es:
ROBLEDO, G; LAVIA, G.; SEIJO, JG
Revista:
THEORETICAL AND APPLIED GENETICS
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2009 vol. 118 p. 1295 - 1307
ISSN:
0040-5752
Resumen:
Abstract Section Arachis of the homonymous genus
includes 29 wild diploid species and two allotetraploids (A.
monticola and the domesticated peanut, A. hypogaea L.).
Although, three diVerent genomes (A, B and D) have been
proposed for diploid species with x = 10, they are still not
well characterized. Moreover, neither the relationships
among species within each genome group nor between diploids
and tetraploids (AABB) are completely resolved. To
tackle these issues, particularly within the A genome, in
this study the rRNA genes (5S and 18S26S) and heterochromatic
bands were physically mapped using Xuorescent
in situ hybridization (FISH) in 13 species of Arachis. These
molecular cytogenetic landmarks have allowed individual
identiWcation of a set of chromosomes and were used to
construct detailed FISH-based karyotypes for each species.
The bulk of the chromosome markers mapped revealed
that, although the A genome species have a common karyotype
structure, the species can be arranged in three groups
(La Plata River Basin, Chiquitano, and Pantanal) on the
basis of the variability observed in the heterochromatin and
18S26S rRNA loci. Notably, these groups are consistent
with the geographical co-distribution of the species. This
coincidence is discussed on the basis of the particular
reproductive traits of the species such as autogamy and
geocarpy. Combined with geographic distribution of the
taxa, the cytogenetic data provide evidence that A. duranensis
is the most probable A genome ancestor of tetraploid
species. It is expected that the groups of diploid species
established, and their relation with the cultigen, may aid to
rationally select wild species with agronomic traits desirable
for peanut breeding programs.