Histo-differentiation and molecular biology of developing cereal endosperm

Olsen, Odd‐Arne; Potter, Robert H.; Kalla, Roger

doi:10.1017/s0960258500001240

Cited by 67 publications

(50 citation statements)

References 86 publications

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“…Analysis of the microtubule cycle provides a new perspective on the syncytial, cellularization, and differentiation stages of endosperm development as defined by Bosnes et al (1992) and Olsen et al (1992). Whereas the mitotic apparatus is essentially the same throughout development, the pattern of cortical microtubules and the cytokinetic apparatus differ with stages of development.…”

Section: Discussionmentioning

confidence: 99%

Endosperm Development in Barley: Microtubule Involvement in the Morphogenetic Pathway.

1994

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An immunofluorescence study of sectioned barley endosperm imaged by confocal laser scanning microscopy provided three-dimensional data on the relationship of microtubules to the cytoplasm, nuclei, and cell walls during development from 4 to 21 days after pollination (DAP). Microtubules play an important role throughout endosperm ontogeny. The syncytium is organized into units of nuclear-cytoplasmic domains by nuclear-based radial microtubule systems that appear to control the pattern of the first anticlinal walls at 5 to 6 DAP. After 7 DAP, phragmoplasts of two origins (interzonal and cytoplasmic) guide wall formation. Large compartments formed by the "free growing" walls in association with cytoplasmic phragmoplasts formed adventitiously at interfaces of opposing microtubule systems are subsequently subdivided by interzonal phragmoplastlcell plates to give rise to the starchy endosperm. During development of the aleurone layer from 8 to 21 DAP, the microtubule cycle is typical of plant histogenesis; cortical microtubules are hooplike, and preprophase bands of microtubules predict the division plane. INTRODUCTIONIn spite of the enormous economic importance of cereal endosperm in agriculture and industry, surprisingly little is known about its development and evolution. The endosperm is an enigma in that (1) it is a product of double fertilization &e., the union of one sperm cell with the egg results in the diploid zygote and the other sperm with one or more nuclei results in the primary endosperm nucleus); (2) unlike the embryo, which follows generally recognized patterns of plant histogenesis, the endosperm is so unlike any other plant tissue that it has been called a monstrosity; and (3) the endosperm has proven extremely difficult to study because in its early stage, it is a delicate liquid coenocyte contained within the innermost chamber of the developing seed.The evolutionary introduction of the endosperm into the life cycle of angiosperms is unknown. Double fertilization occurs in gymnosperms (Friedman, 1992), but the second fertilization results in an additional embryo that competes for resources during development. In angiosperms, the second fertilization results in the primary endosperm nucleus from which develops the nutritive tissue. The endosperm could either be a delayed continuation of female gametophyte development triggered by the second fertilization event and therefore homologous to the nutritive gametophyte in gymnosperms (Thomas, 1907), or the endosperm may be a highly modified supernumerary embryo (Sargant, 1900). Support for the second hypothesis is amassed by Friedman (1994), who argues that the endosperm is a homolog of the embryo, or in other words, an organism in its ownTo whom correspondence should be addressed.right. Recent molecular data demonstrating the expression of the same or homologous genes in the embryo and endosperm (Aalen et al., 1994) lend support to this view. From this perspective, the endosperm emerges as a model system for the study of plant development. It is abundant...

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Section: Discussionmentioning

confidence: 99%

Endosperm Development in Barley: Microtubule Involvement in the Morphogenetic Pathway.

1994

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“…Although dorsal/ventral sections of aleurone layer were also taken, these proved difficult to prepare reproducibly. In addition, the ventral section contained a large region of suture tissue that is very different from the rest of the aleurone layer (Cochrane and Duffus, 1980;Olsen et al, 1992). Because of these difficulties, we restricted our analysis to the proximal/distal and left/right regions.…”

Section: Plant Materials and Aleurone Cell Preparationmentioning

confidence: 99%

The Sensitivity of Barley Aleurone Tissue to Gibberellin Is Heterogeneous and May Be Spatially Determined1

et al. 1999

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In cereals, gibberellin (GA) enhances the synthesis and secretion of hydrolytic enzymes from aleurone cells. These enzymes then mobilize the endosperm storage reserves that fuel germination. The dose-response curve of aleurone protoplasts to GA extends over a range of concentrations from 10 ؊11 to more than 10 ؊6 M. One hypothesis is that subpopulations of cells have different sensitivities to GA, with each cell having a threshold concentration of GA above which it is switched on. The dose-response curve therefore reflects a gradual recruitment of cells to the pool exhibiting a full GA response. Alternatively, all cells may gradually increase their responses as the GA level is increased. In the present study we found that at increasing GA concentrations, increasing numbers of barley (Hordeum vulgare) cells showed the enhanced amylase secretion and vacuolation characteristic of the GA response. We also observed that the region of aleurone tissue closest to the embryo contains the highest proportion of cells activated at the GA concentrations thought to occur naturally in germinating grain. These data indicate that an aleurone layer contains cells of varying sensitivities to GA and that recruitment of these differentially responding pools of cells may explain the broad dose response to GA.

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“…The aleurone layer of the cereal grain is composed of specialized cells surrounding the starchy endosperm, the site for starch and storage protein accumulation in the developing grain (Bosnes et al, 1992;Olsen et al, 1992). After completion of the initial cellularization process of the barley endosperm during the cellularization stage (for endosperm staging, see Bosnes et al, 1992), differentiation of aleurone cells is initiated in the periphery of the endosperm at 8 days after pollination (d.a.p.).…”

Section: Introductionmentioning

confidence: 99%

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

Kalla

Shimamoto²,

Potter³

et al. 1994

The Plant Journal

145

105

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SummaryThis paper describes the aleurone-specific gene Ltp2 from barley, which encodes a putative 7 kDa nonspecific lipid transfer protein. As shown by Northern and in situ hybridization analyses, the Ltp2trenscript is present in barley aleurone cells shortly after the initiation of aleurone cell differentiation. The expression of Ltp2 Increases until grain mid-maturity, but the mRNA is absent from mature grains. The Ltp2 transcript is undstectable in the embryo and vegetative tissues, confirming the aleurone specificity of the Ltp2 gene. The ability of the isolated 801 bp Ltp2 promoter to direct aleurone-specific expression in immature barley grains is demonstrated by perticle bombardment experiments. In these experiments, the activity of the Ltp2 promoter is 5% of the activity of the strong constitutive Actinl promoter from rice, as quantified by GUS activity measurements. In stably transformed rice plants containing the Ltp2 promoter-Gus construct, the specificity of the Ltp2 promoter is confirmed in vivo by the presence of GUS activity exclusively in the aleurone layer. This study demonstrates the conserved nature of the regulatory signals involved in aleurone-specific gene transcription in cereal grains.

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Histo-differentiation and molecular biology of developing cereal endosperm

Cited by 67 publications

References 86 publications

Endosperm Development in Barley: Microtubule Involvement in the Morphogenetic Pathway.

Endosperm Development in Barley: Microtubule Involvement in the Morphogenetic Pathway.

The Sensitivity of Barley Aleurone Tissue to Gibberellin Is Heterogeneous and May Be Spatially Determined1

The promoter of the barley aleurone‐specific gene encoding a putative 7 kDa lipid transfer protein confers aleurone cell‐specific expression in transgenic rice

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