Pablo Aleza1, José Juárez, Patrick Ollitrault, Luis Navarro. 1. Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Ctra. Moncada-Náquera km 4·5, Moncada, Valencia, Spain.
Abstract
BACKGROUND AND AIMS: Adventitious embryony from nucellar cells is the mechanism leading to apomixis in Citrus sp. However, singular cases of polyembryony have been reported in non-apomictic genotypes as a consequence of 2x × 4x hybridizations and in vitro culture of isolated nucelli. The origin of the plants arising from the aforementioned processes remains unclear. METHODS: The genetic structure (ploidy and allelic constitution with microsatellite markers) of plants obtained from polyembryonic seeds arising from 2x × 4x sexual hybridizations and those regenerated from nucellus culture in vitro was systematically analysed in different non-apomictic citrus genotypes. Histological studies were also conducted to try to identify the initiation process underlying polyembryony. KEY RESULTS: All plants obtained from the same undeveloped seed in 2x × 4x hybridizations resulted from cleavage of the original zygotic embryo. Also, the plants obtained from in vitro nucellus culture were recovered by somatic embryogenesis from cells that shared the same genotype as the zygotic embryos of the same seed. CONCLUSIONS: It appears that in non-apomictic citrus genotypes, proembryos or embryogenic cells are formed by cleavage of the zygotic embryos and that the development of these adventitious embryos, normally hampered, can take place in vivo or in vitro as a result of two different mechanisms that prevent the dominance of the initial zygotic embryo.
BACKGROUND AND AIMS: Adventitious embryony from nucellar cells is the mechanism leading to apomixis in Citrus sp. However, singular cases of polyembryony have been reported in non-apomictic genotypes as a consequence of 2x × 4x hybridizations and in vitro culture of isolated nucelli. The origin of the plants arising from the aforementioned processes remains unclear. METHODS: The genetic structure (ploidy and allelic constitution with microsatellite markers) of plants obtained from polyembryonic seeds arising from 2x × 4x sexual hybridizations and those regenerated from nucellus culture in vitro was systematically analysed in different non-apomictic citrus genotypes. Histological studies were also conducted to try to identify the initiation process underlying polyembryony. KEY RESULTS: All plants obtained from the same undeveloped seed in 2x × 4x hybridizations resulted from cleavage of the original zygotic embryo. Also, the plants obtained from in vitro nucellus culture were recovered by somatic embryogenesis from cells that shared the same genotype as the zygotic embryos of the same seed. CONCLUSIONS: It appears that in non-apomictic citrus genotypes, proembryos or embryogenic cells are formed by cleavage of the zygotic embryos and that the development of these adventitious embryos, normally hampered, can take place in vivo or in vitro as a result of two different mechanisms that prevent the dominance of the initial zygotic embryo.
Authors: Y Froelicher; D Dambier; J B Bassene; G Costantino; S Lotfy; C Didout; V Beaumont; P Brottier; A M Risterucci; F Luro; P Ollitrault Journal: Mol Ecol Resour Date: 2008-01 Impact factor: 7.090
Authors: Pablo Aleza; José Juárez; María Hernández; José A Pina; Patrick Ollitrault; Luis Navarro Journal: BMC Plant Biol Date: 2009-08-22 Impact factor: 4.215
Authors: François L Luro; Gilles Costantino; Javier Terol; Xavier Argout; Thierry Allario; Patrick Wincker; Manuel Talon; Patrick Ollitrault; Raphael Morillon Journal: BMC Genomics Date: 2008-06-16 Impact factor: 3.969
Authors: Pablo Aleza; Yann Froelicher; Sergio Schwarz; Manuel Agustí; María Hernández; José Juárez; François Luro; Raphael Morillon; Luis Navarro; Patrick Ollitrault Journal: Ann Bot Date: 2011-05-17 Impact factor: 4.357