CERZOS   05458
CENTRO DE RECURSOS NATURALES RENOVABLES DE LA ZONA SEMIARIDA
Unidad Ejecutora - UE
artículos
Título:
Genomic relationships between hexaploid Helianthus resinosus and diploid Helianthus annuus (Asteraceae)
Autor/es:
JULIETA MIRANDA ZANETTI EDUARDO GREIZERSTEIN ELSA CAMADRO MO´NICA POVERENE MERCEDES ECHEVERRı´A LIDIA POGGIO ALICIA CARRERA
Revista:
PLANT SYSTEMATICS AND EVOLUTION
Editorial:
SPRINGER WIEN
Referencias:
Lugar: Viena; Año: 2013 vol. 300 p. 1071 - 1078
ISSN:
0378-2697
Resumen:
Abstract Genus Helianthus comprises diploid and polyploid
species. An autoallopolyploid origin has been proposed
for hexaploid species but the genomic relationships remain
unclear. Mitotic and meiotic studies in annual Helianthus
annuus (2n = 2x = 34) and perennial Helianthus resinosus
(2n = 6x = 102) as well as the F1 hybrids between both
species were carried out. Chromosome counting confirmed
the hybrid origin of the latter plants and their tetraploid
condition. Bivalents in hybrids ranged from 12 to 28
(x = 20.8). Univalents, trivalents and quadrivalents were
also observed. Meiotic products comprised dyads, triads and
normal tetrads and pollen grains were heterogeneous in size.
These observations suggest the occurrence of 2n pollen in
addition to the expected n. Genomic in situ hybridization
(GISH) of total H. annuus DNA on H. resinosus chromosomes
rendered weak but uniform signals; similar hybridization
pattern was observed using three other annual
species. Hybridization with H. annuus probe performed on
root tip cells of F1 H. annuus9H. resinosus hybrids revealed
17 chromosomes with a strong hybridization signal. GISH in
hybrid meiocytes distinguished chromosomes from parental
species and revealed autosyndetic pairing of H. resinosus
chromosomes, allosyndetic pairing in bivalents, trivalents
and quadrivalents, and the presence of univalents derived
from parents, H. annuus and H. resinosus. Results obtained
from classical and molecular cytogenetics do not support H.
annuus as a direct ancestor of H. resinosus. The occurrence
of allosyndetic pairing and the relatively high fertility of the
F1 hybrids point to the possibility that useful genes could be
transferred from H. resinosus to cultivate sunflower,
although the effective rate of recombination has not been
evaluated. GISH method proved effective to recognize
parental chromosomes in H. annuus9H. resinosus progeny.