Embryogenesis in Higher Plants: An Overview

West, Marilyn A. L.; Harada, John J.

doi:10.2307/3869788

Cited by 119 publications

(81 citation statements)

References 35 publications

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“…The tissue used may be for itself a reason of this variation in the levels of expression of the housekeeping genes. Embryogenesis of higher plants is divided conceptually into two distinct phases: early morphogenetic processes that give rise to embryonic cell types, tissues, and organs and late maturation events that allow the fully developed embryo to enter a desiccated and quiescent state (West and Harada 1993;Goldberg et al 1994). It is therefore reasonable to assume that the level of expression of the genes tested has such a high variability due to these major developmental changes during embryo development.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of control transcripts in real-time RT-PCR expression analysis during maritime pine embryogenesis

Gonçalves

Cairney

Marôco

et al. 2005

Planta

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In order to determine the suitability of reference or housekeeping genes as internal controls in real-time reverse transcriptase PCR (RT-PCR) assays for quantification of target mRNAs, we studied the levels of expression of four candidate reference genes in maritime pine by real-time RT-PCR. The expression levels obtained for glyceraldehyde-3-phosphate-dehydrogenase, 18S ribosomal RNA, eukaryotic translation initiation factor eIF4AII and ubiquitin in nine stages of embryo development revealed that none of the genes tested proved to be suitable as an internal control. Copy number quantification of the four transcripts showed an average relative variation of seven fold. We propose that the combination of a precise method for RNA quantification, internal controls for monitoring RT reaction and PCR efficiency and a robust external standard curve can guarantee a reliable absolute quantification of mRNA transcripts in real time RT-PCR. This approach may avoid the controversy in the use of housekeeping genes and may assume special significance in tissues undergoing developmental changes.

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Section: Discussionmentioning

confidence: 99%

Evaluation of control transcripts in real-time RT-PCR expression analysis during maritime pine embryogenesis

Gonçalves

Cairney

Marôco

et al. 2005

Planta

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“…Ensuing cleavages of the apical cell yield a radially symmetric globular embryo with a differentiated protoderm, or dermatogen. Further cell divisions and subsequent morphogenesis break radial symmetry, yielding the bilaterally symmetric, heart stage embryo with root and shoot apices, incipient cotyledons, and provascular tissue (for recent reviews, se8 Meinke, 1991;Van Engelen and De Vries, 1992;De Jong et al, 1993a;West and Harada, 1993, this issue). So far, few genes have been identified that are expressed specifically during early embryogenesis, primarily because of technical difficulties associated with the mass ratios of the embryo and the surrounding maternal tissue and the lack of molecular and cellular markers to direct screening efforts.…”

Section: Gene Expression In Early Embryosmentioning

confidence: 99%

Gene expression during plant embryogenesis and germination: an overview.

Thomas

1993

Plant Cell

229

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INTRODUCTIONSeed development represents a unique transition state in the life cycle of higher plants, providing the physical link between parenta1 and progeny sporophytic generations. During embrye genesis, the root and shoot apical meristems are specified, thus establishing the basic architecture of the seedling, and differentiation of vegetative tissue and organ systems occurs. Maturation events prepare the seed for germination and subsequent development of the mature plant. During maturation, the developing seed increases dramatically in volume and mass due to significant cell expansion and the concomitant accumulation and storage of protein and lipid to be used as nitrogen and carbon sources during germination. Early during the maturation phase, abscisic acid (ABA) levels reach a maximum, suppressing precocious germination and modulating gene expression. Desiccation ensures seed dormancy even in the absence of ABA and serves as the boundary between seed maturation and germination. Following imbibition, germination and seedling growth ensue, driven metabolically by the hydrolysis of protein and lipid stored during maturation.This review will provide an eclectic overview of gene expression in angiosperm embryogenesis and germination. I will focus primarily on dicot plants and will address only a small number of the more than 3 x 104 different genes expressed in embryos and seedlings. First, gene expression in early embryogenesis will be reviewed, focusing on selected results obtained with carrot somatic embryos. Control of gene expression during seed maturation will then be discussed, with an emphasis on cis-and tfans-acting factors involved in regulating maturation phase genes. A brief description of gene expression during germination and the relationship of embryonic and vegetative gene expression programs will follow. The review will conclude with a prospectus for the study of global gene expression patterns in early embryos. GENE EXPRESSION IN EARLY EMBRYOSAlthough most of the major discernible morphogenetic events in plants occur after germination, the overall architectural pattern of the mature plant is established during embryogenesis (see West and Harada, 1993, this issue). Following fertilization, an asymmetric division of the zygote of many dicots yields a basal cell that will produce the suspensor and an apical cellthe first embryonic cell. Ensuing cleavages of the apical cell yield a radially symmetric globular embryo with a differentiated protoderm, or dermatogen. Further cell divisions and subsequent morphogenesis break radial symmetry, yielding the bilaterally symmetric, heart stage embryo with root and shoot apices, incipient cotyledons, and provascular tissue (for recent reviews, se8 Meinke, 1991;Van Engelen and De Vries, 1992;De Jong et al., 1993a;West and Harada, 1993, this issue). So far, few genes have been identified that are expressed specifically during early embryogenesis, primarily because of technical difficulties associated with the mass ratios of the embryo and the surrounding mate...

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“…The first phase is characterized by embryo morphogenesis during which the polar axis of the plant body is defined concomitantly with the specification of shoot and root apical meristems and the formation of vegetative tissues and organ systems. The second phase represents embryo maturation in which high levels of storage reserves in the form of proteins, lipids, and carbohydrates accumulate (West and Harada 1993). During the final phase of embryo development, a fundamental difference between the seeds of two classes of plants is exhibited.…”

Section: Introductionmentioning

confidence: 99%

Protein expression during seed development in Araucaria angustifolia: transient accumulation of class IV chitinases and arabinogalactan proteins

Santos¹,

Wiethölter²,

Gueddari³

et al. 2006

Physiologia Plantarum

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Protein accumulation and patterns during embryogenesis in the recalcitrant seeds of the gymnosperm species Araucaria angustifolia (Bert.) O. Kuntze were studied. Soluble seed proteins, chitinases, and arabinogalactan proteins (AGPs) were analyzed by means of 2-D gel electrophoresis, mass spectrometry, isoelectric focusing, Western blot, precipitation and staining with b-glucosyl Yariv reagent (b-Glc) 3 Y, and gas liquid chromatography. Despite the recalcitrant nature of the seeds, the electrophoretic patterns of A. angustifolia seed proteins showed similarities with orthodox seed types. Proteins showing chitinolytic activity were observed in all seed stages analyzed, but the expression of class IV chitinases was restricted to late stages of seed development. AGPs were prominent during stages of seed development characterized by intensive cell division and differentiation, and their decrease during seed maturation might be related to cell wall modifications during the deposition of storage compounds. Gas liquid chromatographic analyzes of AGPs did not show quantitative changes in their carbohydrate moieties during seed development. A low molecular weight protein specifically expressed in mature seeds was precipitated using (b-Glc) 3 Y. Amino acid sequences obtained from MS/MS analysis revealed peptides rich in valine and acidic amino acids, but devoid in amino acids normally found in AGPs polypeptides, suggesting that these peptides are not related to classical or non-classical AGPs. Possible implications of chitinases and AGPs during seed development in A. angustifolia are discussed.

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Embryogenesis in Higher Plants: An Overview

Cited by 119 publications

References 35 publications

Evaluation of control transcripts in real-time RT-PCR expression analysis during maritime pine embryogenesis

Evaluation of control transcripts in real-time RT-PCR expression analysis during maritime pine embryogenesis

Gene expression during plant embryogenesis and germination: an overview.

Protein expression during seed development in Araucaria angustifolia: transient accumulation of class IV chitinases and arabinogalactan proteins

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