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The regulation of napin gene expression in secondary embryos of Brassica napus
Author(s) -
Fleming Andrew J.,
Hanke David E.
Publication year - 1993
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1993.tb01747.x
Subject(s) - embryo , biology , somatic embryogenesis , zygote , somatic cell , cotyledon , embryogenesis , maternal to zygotic transition , microbiology and biotechnology , genetics , gene , botany
Embryos derived from somatic tissues proceed through a series of morphological stages very similar to those observed during zygotic embryo development. However, somatic embryos do show some developmental characteristics distinct from those of zygotic embryos (e. g. curtailed cotyledon filling, precocious germination) which are not observed in zygotic embryos in vivo. Whether these differences reflect the abnormality of the in vitro culture environment or whether they are due to biochemical or developmental peculiarities of the somatic embryos is unclear. Using a system of secondary embryogenesis in Brassica napus cv. Primor, we have attempted to address this problem by analysing the level of napin storage protein transcripts and their regulation by ABA throughout somatic embryo development. We have in addition measured the endogenous levels of ABA in the embryos, and characterised the effect of ABA (and other medium components) on napin transcript level, embryo germination, and embryo survival. Our analysis, in conjunction with the published data on zygotic and microspore‐derived embryo development, allows us to conclude that although somatic and zygotic embryos show the same basic pattern of napin gene expression and regulation, the secondary embryos are characterised by a basal constitutive derepression of the napin gene, in contrast to the tight developmental control reported in zygotic embryos.