title: Protocols for Obtaining Zygotic and Somatic Embryos for Studying the Regulation of Early Embryo Development in the Model Legume Medicago truncatula.
abstract: Early embryogenesis starting from a single cell zygote goes through rapid cell division and morphogenesis, and is morphologically characterized by pre-globular, globular, heart, torpedo and cotyledon stages. This progressive development is under the tight regulation of a complex molecular network. Harvesting sufficient early embryos at a similar stage of development is essential for investigating the cellular and molecular regulation of early embryogenesis. This is not straightforward since early embryogenesis undergoes rapid morphogenesis in a short while e.g. 8 days for Medicago truncatula to reach the early cotyledon stage. Here, we address the issue by two approaches. The first one establishes a linkage between embryo development and pod morphology in helping indicate the stage of the zygotic embryo. This is particularly based on the number of pod spirals and development of the spines. An alternative way to complement the in vivo studies is via culturing leaf explants to produce somatic embryos. The medium includes an unusual hormone combination - an auxin (1-naphthaleneacetic acid), a cytokinin (6-benzylaminopurine), abscisic acid and gibberellic acid. The different stages can be discerned growing out of the callus without dissection.
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Kurdyukov
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Youhong
authors.initials: Y
authors.lastname: Song
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Terence W-Y
authors.initials: TW
authors.lastname: Tiew
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Xin-Ding
authors.initials: XD
authors.lastname: Wang
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Kim E
authors.initials: KE
authors.lastname: Nolan
authors.affiliation: School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia; ray.rose@newcastle.edu.au.
authors.forename: Ray J
authors.initials: RJ
authors.lastname: Rose
mesh_terms: D004626:Embryology / Q000379:methods; D046913:Medicago truncatula / Q000166:cytology / Q000196:embryology* / Q000254:growth & development; D012639:Seeds / Q000166:cytology / Q000196:embryology* / Q000254:growth & development