Polyembryonyin Non-apomictic Citrus Genotypes
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2010Cita bibliográfica
Aleza, P., Juarez, J., Ollitrault, P., & Navarro, L. (2010). Polyembryonyin non-apomictic citrus genotypes. In Vitro Cellular & Developmental Biology-Animal, 46, S145-S145.Abstract
Adventitious embryony from nucellar cells is the mechanism
leading to apomixis in citrus. However, singular cases
of polyembryony have been reported in non-apomictic
genotypes as a consequence of 2x×4x hybridisations and in
vitro culture of isolated nucellus. The origin of the plants
obtained as a consequence of these two processes is still
unclear. In this work, we systematically analyzed the
genetic structure (ploidy and allelic constitution at SSR
locus) of plants obtained from polyembryonic seeds arising
from 2x×4x sexual hybridisations or regenerated from
nucellus culture in vitro of different non-apomictic citrus
genotypes. Histological studies were also conduced to try to
identify the initiation process of polyembryony in nonapomictic
genotypes. We demonstrate that all plants
obtained from the same undeveloped seed in 2x×4x
hybridisations resulted from fission of the original zygotic
embryo. Also, the plants obtained from in vitro culture of
nucellus were recovered by somatic embryogenesis from
cells having the same genotype as the zygotic embryos of
the same seed. It appears that in non-apomictic citrus,
proembryos or embryogenic cells are formed by fission of
the original zygotic embryo and that the development of
these adventitious embryos, normally hampered, can take
place in vivo or in vitro as result of two different mechanisms that prevent the dominance of the initial
zygotic embryo.