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Aleurone

The aleurone layer is a specialized peripheral tissue in the endosperm of seeds from many angiosperms, particularly prominent in cereal grains such as maize, wheat, barley, and rice, where it consists of one or more layers of cuboidal, living cells located between the starchy endosperm and the seed coat.^[1] These cells are characterized by thick, autofluorescent cell walls, protein bodies, lipid droplets, and the absence of starch granules, enabling them to store essential nutrients including proteins, lipids, minerals, vitamins, and bioactive compounds like polyphenols and ferulic acid.^[1]^[2] In non-cereal plants like soybeans, the aleurone forms a single, transparent cell layer between the seed coat and cotyledons, enriched in storage proteins and defense-related compounds.^[3] During seed development, the aleurone arises from the outermost cells of the triploid endosperm following cellularization, with its formation genetically regulated by genes such as DEK1, CR4, and NKD in maize, and environmental factors like temperature influencing layer thickness and composition across species (e.g., one layer in wheat, three in barley).^[1] Upon germination, triggered by hormones like gibberellins, aleurone cells synthesize and secrete hydrolytic enzymes—including α-amylase, proteases, and nucleases—that degrade macromolecules in the adjacent starchy endosperm, mobilizing nutrients to support embryo growth while the aleurone itself undergoes programmed cell death.^[1] This tissue also contributes to seed dormancy regulation via abscisic acid signaling and serves as a barrier against pathogens.^[1] Nutritionally, aleurone is a rich source of dietary fiber (e.g., arabinoxylans and β-glucans), folate, betaine, and antioxidants, a major component of the bran which contains most of the fiber in wheat grains and offering potential health benefits such as improved gut microbiota composition (e.g., increased Bifidobacterium species) and reduced cardiovascular disease biomarkers like LDL cholesterol and C-reactive protein in human studies.^[1]^[2] In breeding applications, aleurone traits are targeted to enhance grain nutritional quality, with mutations altering layer number to boost micronutrient content, though challenges include pleiotropic effects on yield.^[1]

Structure and Composition

Cellular Structure

The aleurone layer is a specialized epidermal tissue forming the outermost covering of the endosperm in cereal grains, consisting of living cells that surround the starchy endosperm.^[4] This layer typically comprises one to several cells in thickness, with a single layer observed in species such as wheat, rice, and maize, while barley features three layers.^[5] These cells remain viable at seed maturity, distinguishing them from the inner endosperm cells that undergo programmed cell death.^[6] Aleurone cells exhibit a cuboidal or polyhedral morphology, appearing cuboid in cross-section and polygonal from the top view, with dimensions varying by cereal species (e.g., 37–65 µm in length for wheat).^[7] Their cell walls are notably thick, measuring 3–5 µm, and are reinforced with polysaccharides including β-glucans and arabinoxylans that contribute to structural integrity.^[8] Within the cytoplasm, prominent aleurone grains—specialized protein bodies or storage vacuoles—occupy much of the cell volume; these contain inclusions such as phytin, the calcium-magnesium salt of phytic acid, and electron-dense globoids rich in minerals like phosphorus, magnesium, and calcium.^[9] Intercellular connections via plasmodesmata link aleurone cells to adjacent starchy endosperm cells, facilitating symplastic transport of nutrients and signals.^[10] Pigmentation in aleurone cells varies across species, often resulting from anthocyanin accumulation that imparts color to the kernel. In maize, for instance, anthocyanins synthesized in the aleurone layer produce purple, red, or blue hues in kernels, influenced by genetic factors regulating pigment biosynthesis.^[11]

Chemical Composition

Aleurone cells are characterized by their high protein content, which can constitute up to 30% of the total proteins in the kernel of certain cereals like maize. These proteins primarily include storage forms such as globulins (e.g., 7S globulins and α-globulins), prolamins (e.g., zeins in maize), and various enzymes sequestered within specialized organelles known as aleurone grains.^[12]^[13]^[14] In wheat, for instance, proteins associated with type II inclusions in aleurone cells account for 15-20% of the grain's total protein mass.^[15] Lipids in aleurone cells are stored predominantly as triacylglycerols (oils) and phospholipids within spherosomes, also referred to as oil bodies or lipid droplets. These organelles, bounded by a single membrane, comprise 50-80% of the total lipids in tissues like the aleurone layer and scutellum in wheat, serving as a concentrated reserve distinct from the starch-dominated endosperm.^[7]^[16]^[17] Minerals accumulate substantially in aleurone cells, with phosphorus primarily stored as phytin (phytate or inositol hexaphosphate) within globoid inclusions of protein storage vacuoles; in rice, for example, the aleurone layer harbors about 90% of the grain's total phosphorus. Additionally, aleurone is enriched with vitamins, including vitamin E (tocopherols and tocotrienols) and B-group vitamins such as niacin (up to 80% of the grain's total in wheat) and thiamine.^[18]^[19]^[15]^[20] Unlike the starchy endosperm, aleurone cells contain limited carbohydrates, restricted mainly to cell wall polysaccharides such as arabinoxylans and β-glucans, with no significant starch accumulation. This composition underscores the aleurone's role as a nutrient-dense peripheral tissue.^[15]^[21]^[22] Aleurone grains, or protein storage vacuoles, exhibit a distinctive structure featuring a proteinaceous matrix embedding crystalline inclusions of globulins and phytin globoids, which store both proteins and minerals in a compact, membrane-bound form typically 2-4 μm in diameter. These inclusions, including crystalloids of prolamins and globulins alongside phytate-rich globoids, enable efficient packaging and mobilization of reserves.^[23]^[13]^[24]

Occurrence in Plants

In Cereal Grains

The aleurone layer is a ubiquitous feature of cereal grains, present in major species such as maize (Zea mays), wheat (Triticum aestivum), rice (Oryza sativa), barley (Hordeum vulgare), and sorghum (Sorghum bicolor), where it forms a specialized outer covering around the starchy endosperm.^[1] This positioning allows the aleurone to serve as a protective and nutrient-rich boundary between the endosperm and the pericarp, contributing to the overall architecture of the mature seed. In these cereals, the aleurone originates as part of the triploid (3n) endosperm tissue, resulting from double fertilization in which one sperm nucleus fuses with the two polar nuclei of the central cell, in contrast to the diploid (2n) embryo formed by fusion with the egg cell.^[1] Variations in aleurone layer thickness are characteristic across cereal species, reflecting adaptations to environmental and genetic factors. Maize and wheat typically feature a single layer of aleurone cells, while barley consistently exhibits three layers, and sorghum maintains a single layer similar to maize.^[25] In rice, the layer is often single-celled but can become multilayered (up to four to six cells thick) in a site-specific manner, with greater thickness on the dorsal side of the grain influenced by developmental cues like temperature and photoperiod.^[1]^[26] These structural differences impact grain quality and processing outcomes. The aleurone holds significant economic importance in cereal processing, particularly during milling, where it constitutes a major component of the bran fraction alongside the pericarp and is valued for its high content of dietary fiber, proteins, vitamins, and minerals.^[15] In wheat, for instance, the aleurone accounts for about 5-8% of the kernel weight and up to 50% of the bran, providing arabinoxylans and β-glucans that enhance the nutritional profile of whole-grain products like bread and pasta, though extraction challenges limit its isolated commercial use.^[15] This nutrient density supports the growing demand for functional foods, boosting the value of bran by-products in food industries. A notable variation occurs in maize, where the aleurone can become pigmented, leading to purple or red kernels due to anthocyanin biosynthesis within the cells.^[27] Genes such as Purple aleurone1 (Pr1) regulate the production of cyanidin- or pelargonidin-based pigments, with total anthocyanin levels reaching up to 1598 µg/g in certain varieties, contributing to both aesthetic traits and potential health benefits from antioxidants.^[27]

In Non-Cereal Seeds

In dicot seeds, such as those of soybean (Glycine max), the aleurone layer forms a thin, single-cell-thick tissue positioned between the seed coat and the cotyledons, serving as the outermost remnant of the endosperm.^[28] This layer lines the embryo sac and adheres to the inner structures of the seed coat, becoming compressed during seed filling as cotyledons expand.^[29] Unlike the multilayered aleurone in cereals, this structure in most non-cereal species consists of a single layer of viable cells, reflecting a simplified organization adapted to seeds where storage is primarily in cotyledons rather than extensive endosperm.^[5] In oilseeds like Arabidopsis thaliana, a model brassica, the aleurone exhibits adaptations suited to lipid-rich environments, accumulating both storage proteins in protein storage vacuoles and lipids in oleosomes within its cells.^[30] This contrasts with the protein-dominant composition typical of cereal aleurone, highlighting evolutionary adjustments in non-cereal lineages where overall seed storage favors triacylglycerols over starch and globulins.^[31] The aleurone cells feature thick cellulose walls and respond to hormonal signals, maintaining structural integrity around the embryo. Examples from legumes, including soybean, and brassicas, such as Arabidopsis, demonstrate the aleurone's contributions to seed vigor and dormancy; in soybean, it enriches in proteins for oxidative stress responses, aiding tolerance to abiotic and biotic challenges that influence vigor.^[28] In Arabidopsis, the layer is essential for dormancy regulation, responding to nitric oxide, gibberellin, and abscisic acid to control embryo growth potential and prevent premature germination.^[32] These roles underscore the tissue's protective functions in non-cereal seeds. The aleurone represents an evolutionarily conserved endosperm-derived tissue across angiosperms, present in the majority of species as an outer epidermal-like layer, though it remains less extensively studied outside cereals due to the economic emphasis on grain crops.^[33]

Development

Formation During Seed Maturation

In cereal seeds, the aleurone layer originates from the triploid endosperm tissue formed immediately after double fertilization, where one sperm nucleus fuses with the central cell to produce the coenocytic endosperm. This initial stage features free nuclear divisions without cytokinesis, resulting in a syncytial structure where thousands of nuclei proliferate within a shared cytoplasm.^[34] As seed development progresses, these nuclei migrate toward the endosperm periphery, setting the stage for cellularization that begins around 5-10 days after pollination (DAP) in most cereals.^[35] Cellularization initiates at the outer endosperm layer, forming cell walls around individual nuclei in a centripetal manner, which establishes the protoderm-like aleurone primordium. This process involves oriented periclinal divisions, which expand the layer radially, and anticlinal divisions, which increase tangential coverage, primarily in the outermost cells.^[36] Environmental factors, particularly temperature during the grain-filling period, influence aleurone layer thickness; for instance, higher temperatures promote thicker dorsal aleurone in rice by enhancing cell proliferation. By 20-30 days post-anthesis, the maturing aleurone cells undergo significant accumulation of storage reserves, including proteins, lipids, and minerals, while their cell walls thicken to provide structural integrity and support dormancy acquisition.^[1]

Cellular Differentiation

Aleurone differentiation in cereal grains is initiated around mid-seed development, typically 8-10 days post-anthesis (DPA), when peripheral triploid endosperm cells begin to specialize from the surrounding coenocytic syncytium.^[37] This process transforms these founder cells into a distinct layer of cuboidal-shaped aleurone cells, characterized by their compact arrangement and the development of prominent cell walls that contribute to the structural integrity of the peripheral endosperm.^[5] The timing aligns with the transition from proliferative growth to maturation phases in the seed, ensuring the aleurone layer forms a protective outer boundary.^[37] Establishing the boundary between aleurone and inner starchy endosperm involves asymmetric cell divisions, particularly periclinal divisions in species like maize, where outer daughter cells adopt aleurone fate while inner ones differentiate into starchy endosperm.^[38] These divisions are guided by positional cues that maintain aleurone identity, with key genes such as cr4 (encoding a receptor-like protein) playing a critical role in boundary maintenance by responding to these signals.^[38] During this phase, aleurone cells acquire epidermal-like traits, including the restriction of plasmodesmata to limit symplastic transport, thereby isolating the layer from the starchy endosperm.^[5] Unlike the central starchy endosperm cells, which undergo programmed cell death (PCD) starting around 16 DPA to facilitate nutrient mobilization, aleurone cells actively avoid PCD during seed maturation, preserving their viability through desiccation.^[37] This survival mechanism involves regulatory pathways that suppress autophagic and nuclease activities, allowing aleurone cells to remain metabolically active in mature grains.^[5] Studies have revealed dynamic modifications in the aleurone cell cycle, including endoreduplication in cereals like barley and maize, where cells undergo additional rounds of DNA replication without mitosis to support protein synthesis and storage accumulation without further division.^[39] These modifications enhance ploidy levels in aleurone cells, contributing to their specialized metabolic capacity during late seed development.^[40]

Functions

Nutrient Storage

The aleurone layer functions as a key reserve tissue in seeds, accumulating proteins, minerals, and lipids to sustain the embryo during early development. In cereal grains such as wheat, aleurone cells store proteins at concentrations reaching up to 40% of their dry weight, representing 15-20% of the total grain proteins and serving as a major nitrogen source for the seedling.^[15] Lipids, comprising 5-10% of the aleurone dry matter, are sequestered in oil bodies and provide essential energy reserves.^[15] Minerals like phosphorus, potassium, and magnesium are primarily stored as phytin, a salt of phytic acid, which accounts for 60-80% of the total phosphorus in the aleurone and up to 70% of the seed's mineral content.^[41] These storage forms ensure a compact, stable repository of nutrients within the limited volume of aleurone cells. Phytin is crystallized into electron-dense globoids within protein storage vacuoles of aleurone grains, where its multiple phosphate groups act as a buffer by chelating cations such as Ca²⁺, Mg²⁺, and K⁺ to form insoluble complexes.^[41] This sequestration prevents cytosolic accumulation of free phosphate and minerals, which could otherwise precipitate and cause cellular toxicity by disrupting metabolic processes.^[41] In wheat aleurone, phytin concentrations range from 8.4 to 15.6 g per 100 g dry weight, highlighting its role as an efficient phosphate reserve that maintains cellular homeostasis during seed maturation.^[15] The stored nutrients in aleurone contribute significantly to the overall nutritional value of seeds, particularly through enhanced mineral bioavailability following hydrolysis. During processing or germination, phytase enzymes degrade phytin, releasing chelated minerals in forms that are more accessible for absorption, thereby improving the seed's utility as a food source rich in bioavailable phosphorus, magnesium, and other elements.^[15] In non-cereal seeds like soybean, the aleurone layer, a single-cell sheath between the seed coat and cotyledons, stores proteins such as β-conglycinin and oil bodies while regulating nutrient flux to support cotyledon accumulation of storage reserves.^[3] Depletion of aleurone reserves occurs during seed aging or exposure to stress, such as high temperature and humidity, leading to disrupted cellular integrity and reduced nutrient availability that compromises seed viability. In aged oat seeds, for instance, embryo cell swelling and disordered arrangement at the embryo-endosperm junction hinder gibberellin signaling to the aleurone and enzyme activity, resulting in germination rates dropping as low as 4% after prolonged stress.^[42] This loss of storage capacity underscores the aleurone's critical role in maintaining seed longevity under adverse conditions.

Role in Germination

During seed germination in cereals, the aleurone layer is activated by gibberellins (GA) produced by the embryo, leading to the synthesis and secretion of hydrolytic enzymes such as α-amylase, proteases, and nucleases into the starchy endosperm.^[43] This process begins shortly after imbibition and is essential for mobilizing stored reserves to support embryo growth.^[44] The enzymes degrade cell walls and storage compounds, with α-amylase primarily hydrolyzing starch into maltose and glucose.^[45] The aleurone layer regulates apoplastic pH to an acidic range of approximately 3.5–5.0, optimizing the activity of these secreted enzymes.^[46] This acidification, mediated by plasma membrane H⁺-ATPases in aleurone cells, creates an electrochemical gradient that facilitates enzyme function and nutrient diffusion from the endosperm to the scutellum.^[46] Abscisic acid (ABA) can inhibit this GA-induced activation, maintaining dormancy until conditions favor sprouting.^[44] Through enzymatic action, the aleurone enables nutrient mobilization by breaking down starch into simple sugars and proteins into amino acids, which are transported to the growing embryo for energy and biosynthesis.^[45] This supports rapid seedling establishment, with the process peaking within the first few days of germination.^[47] Following enzyme secretion, aleurone cells undergo programmed cell death (apoptosis), typically 4–7 days after imbibition in cereals like barley and maize, marked by vacuolation, reactive oxygen species accumulation, and loss of membrane integrity.^[48] This self-sacrifice ensures efficient resource transfer without competition from the aleurone tissue.^[49] In industrial applications, the aleurone layer of barley is central to malting for brewing, where controlled germination induces enzyme production to hydrolyze endosperm reserves, yielding fermentable sugars for beer production.^[1] This process mimics natural germination but is optimized for consistent enzyme output and malt quality.^[50]

Defense Mechanisms

The aleurone layer serves as a primary physical and chemical barrier in cereal grains, protecting the nutrient-rich starchy endosperm from biotic threats such as fungal pathogens. Its thick cell walls, composed primarily of arabinoxylans and cellulose and reinforced by phenolic compounds like ferulic acid dehydrodimers, deter penetration by fungi including Fusarium graminearum, a major cause of head blight in cereals like maize and wheat. These phenolics, concentrated in the aleurone, exhibit antifungal properties by disrupting hyphal growth and enhancing tissue rigidity, thereby contributing to genotypic resistance observed in studies of maize grain.^[51]^[52]^[5] In response to pathogen attack, aleurone cells produce pathogenesis-related (PR) proteins, including PR-4 (such as wheatwin1) and class III chitinases (PR-3 family), which are strategically localized in the bran layers overlying the aleurone to inhibit fungal invasion. Chitinases hydrolyze chitin in fungal cell walls, while PR-4 proteins bind to hyphal structures, preventing endosperm colonization; these proteins are expressed in outer seed layers during development and upon infection signals. This distribution ensures direct antimicrobial action, with aleurone-derived PR proteins playing a key role in containing pathogens like Fusarium species in wheat and other cereals.^[53]^[54]^[5] Aleurone cells also accumulate antioxidant compounds, such as tocopherols (vitamin E forms) and flavonoids, which mitigate oxidative stress during seed maturation and under abiotic pressures like drought or UV exposure. These lipophilic antioxidants, predominantly located in the aleurone layer of wheat and other cereals, scavenge reactive oxygen species (ROS) generated by environmental stresses, preserving cellular integrity and preventing lipid peroxidation in membranes. Flavonoids in particular contribute to ROS homeostasis, supporting aleurone viability and overall grain resilience.^[52]^[55]^[5] Through abscisic acid (ABA) signaling, the aleurone enforces seed dormancy to avert premature germination during stress conditions, such as desiccation or pathogen pressure. ABA, synthesized and responsive in aleurone cells, upregulates genes like HVA22 in barley, inhibiting gibberellin-mediated growth pathways and maintaining dormancy to protect against environmental hazards. This mechanism ensures survival until favorable conditions, with aleurone acting as a key site for ABA perception and transduction in cereals.^[56]^[57]^[5] Recent research highlights the aleurone as a hub for systemic defense signaling in grains, where transcription factors like NKD in maize activate broad networks of defense genes, coordinating responses across seed tissues against biotic stresses. This 2025 analysis underscores aleurone's role in propagating signals for enhanced pathogen resistance, building on earlier work on localized PR expression.^[5]^[1]

Molecular Regulation

Genetic Control

The genetic control of aleurone layer formation and function is primarily elucidated through studies in maize, where specific genes regulate cell fate specification, differentiation, and pigmentation. The DEK1 (defective kernel 1) gene encodes a membrane-bound calpain protease essential for maintaining aleurone cell identity and membrane integrity during endosperm development.^[58] Mutants in DEK1 exhibit a complete absence of the aleurone layer, with peripheral endosperm cells adopting a starchy fate instead, underscoring its role in restricting aleurone specification to the outer endosperm layers.^[59] Similarly, the CR4 (crinkly4) gene, which encodes a receptor-like kinase, mediates cell-autonomous signaling for aleurone fate at endosperm boundaries by perceiving positional cues that promote peripheral cell differentiation. In cr4 mutants, aleurone development is disrupted, resulting in irregular patches of starchy cells interspersed with aleurone, highlighting CR4's function in transducing signals for precise layer boundary establishment.^[60] Transcription factors further fine-tune aleurone development by integrating developmental signals. The VP1 (viviparous1) gene acts as a key regulator in the aleurone, where it functions as a transcriptional activator that enhances abscisic acid (ABA) responsiveness, promoting seed maturation and preventing precocious germination through modulation of downstream gene expression.^[61] In maize, VP1 mutants display reduced ABA sensitivity in the aleurone, leading to viviparous phenotypes.^[62] Complementing this, the O2 (opaque2) transcription factor in maize aleurone influences protein quality by activating zein storage protein synthesis, thereby favoring zeins over lysine-rich globulins and supporting proper cell patterning.^[63] O2 mutants result in opaque endosperm due to disrupted protein body formation.^[64] Pigmentation in the aleurone serves as a visible marker for genetic studies, governed by the anthocyanin biosynthetic pathway. In maize, the C1 (colorless1) and R1 (colored1) genes encode MYB and bHLH transcription factors, respectively, that activate the expression of structural enzymes for anthocyanin production specifically in aleurone cells, resulting in colored kernels when functional.^[65] Mutants in C1 or R1 abolish aleurone pigmentation, facilitating identification of regulatory interactions within the pathway.^[66] Recent advances have identified quantitative trait loci (QTLs) influencing aleurone layer thickness and multilayered structures in cereals, addressing variations beyond single-gene mutants. A 2025 review highlights three QTLs in barley controlling aleurone layer number and thickness, derived from crosses between single- and multi-layered varieties, which could inform breeding for enhanced nutrient storage.^[67] In maize, genetic mapping has identified the multilayered aleurone (MAL) locus on chromosome 8.^[67] These findings emphasize polygenic control in cereals, with potential for marker-assisted selection to optimize aleurone architecture.

Hormonal Influences

Plant hormones play a pivotal role in orchestrating aleurone development and function in cereal seeds, influencing cell differentiation, maturation, reserve accumulation, and germination processes. During early seed development, gradients of auxin and cytokinin guide aleurone cell division patterns and fate specification. High auxin concentrations at the endosperm periphery promote aleurone identity, potentially through polar auxin transport mediated by PIN proteins, while disruptions in auxin flow, such as those induced by inhibitors like N-1-naphthylphthalamic acid (NPA), lead to abnormal multilayered aleurone formation.^[68] In contrast, cytokinin appears to suppress aleurone differentiation; transgenic maize kernels with elevated cytokinin levels exhibit mosaic aleurone patterns, indicating an inhibitory effect on cell fate commitment.^[69] As seeds progress to maturation, abscisic acid (ABA) dominates to facilitate reserve accumulation and establish dormancy. Elevated ABA levels during this phase promote the synthesis and storage of reserves in seeds, enhancing desiccation tolerance and preventing premature activation.^[70] ABA also antagonizes gibberellins (GA), maintaining dormancy by inhibiting GA-responsive pathways and thereby suppressing precocious sprouting in developing grains. This hormonal balance shifts post-imbibition, with declining ABA allowing GA dominance to initiate germination. GA, produced by the embryo, diffuses to the aleurone layer and promotes the transcription of alpha-amylase genes through the transcriptional activator GAMYB, enabling the mobilization of stored reserves.^[71] Ethylene contributes to stress-induced defense mechanisms and the timing of apoptosis in aleurone cells, particularly under abiotic stresses like drought during seed development. In wheat grains exposed to water deficit, ethylene biosynthesis increases, acting as a stress signal to modulate responses in endosperm tissues.^[72] This hormone helps fine-tune the transition to PCD after reserve mobilization, ensuring coordinated seedling establishment while responding to environmental cues. The interplay among these hormones—auxin and cytokinin in patterning, ABA in repression, GA in activation, and ethylene in stress modulation—integrates aleurone responses across developmental stages.

References

[1]
The aleurone layer of cereal grains: Development, genetic ...
Feb 12, 2025 · It is composed of one or more outer layers of endosperm cells situated beneath the seed coat.
[2]
Impact of wheat aleurone on biomarkers of cardiovascular disease ...
Mar 5, 2022 · Aleurone is a cereal bran fraction containing a variety of beneficial nutrients including polyphenols, fibers, minerals and vitamins.
[3]
Characterization and functional biology of the soybean aleurone layer
Dec 13, 2018 · In maturing soybean seeds the aleurone layer is the single cell layer that is situated between the outer seed coat and inner cotyledonary tissue ...
[4]
Regulation of aleurone development in cereal grains
Nov 25, 2010 · The epidermal-like aleurone layer forms on the surface of the endosperm and is important for digesting the endosperm storage products during ...
[5]
The aleurone layer of cereal grains: Development, genetic ...
Apr 14, 2025 · Maize and wheat typically exhibit a single layer of aleurone cells in mature grains, whereas barley (Hordeum vulgare) has three layers (Figure 1 ...
[6]
(PDF) Aleurone Cell Development - ResearchGate
Aug 10, 2025 · The inner layers of endosperm cells undergo programmed cell death, but the cells in the aleurone layer remain alive as seeds mature (Becraft, ...
[7]
Aleurone Cells - an overview | ScienceDirect Topics
Since it is three cell layers thick, the aleurone produces sufficient α-amylase and other enzymes to permit effective brewing.
[8]
[PDF] Structure and Mineral Composition of Cereal Aleurone Cells as ...
The aleurone tissue of cereal grains consists of one (in most species) to three or four (in barley) cell layers that surround the starchy endosperm. The ...
[9]
Aleurone - an overview | ScienceDirect Topics
The protein bodies appear to be organized in a vacuole system. Aleurone cells also contain oil bodies and are also rich in phosphorus (phytin bodies), potassium ...
[10]
Subcellular Localization and Functional Domain Studies of ... - NIH
The plasmodesmata connecting aleurone and starchy endosperm cells show intermediate features between those connecting aleurone cells and those connecting ...
[11]
Genome-wide association study of kernel colour traits and mining of ...
Jan 3, 2024 · Anthocyanins exist mostly in the aleurone layer of maize kernels, and purple corn is particularly rich in anthocyanins [4, 26]. The anthocyanin ...
[12]
Aleurone layer of corn kernel - Corn Journal
Dec 18, 2018 · Although only a single layer of cells, it can include 30% of the total proteins of the endosperm. It is also the location of pigment molecules ...
[13]
Delivery of Prolamins to the Protein Storage Vacuole in Maize ...
Aleurone cells are rich in protein storage vacuoles (PSVs), minerals, and lipid bodies and remain alive during seed development. ... aleurone peels demonstrates ...<|control11|><|separator|>
[14]
Targeting aleurone cells for enhanced protein recovery from wheat ...
1). The 7 S globulins in wheat are the major storage protein in aleurone cells but are not present in starchy endosperm cells (Khan, 2009).
[15]
The Wheat Aleurone Layer: Optimisation of Its Benefits and ... - NIH
As it contains the majority of the grain's minerals and is also rich in protein, DF and bioactive components (mostly ferulic acid), the aleurone layer may be ...
[16]
Isolation and Characterization of the Lipid Reserve Bodies ...
Lipid reserve bodies (spherosomes) isolated from aleurone layers of wheat (Triticum aestivum L.) by combined differential and density gradient ...
[17]
Accumulation and deposition of triacylglycerols in the starchy ...
They are concentrated in the aleurone layer and scutellum of the embryo of wheat, where they account for 60–80% of the total lipids in these tissues (Chung et ...
[18]
Phytate: impact on environment and human nutrition. A challenge for ...
Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize) ...
[19]
Rice with Multilayer Aleurone: A Larger Sink for Multiple Micronutrients
In rice, the bran tissues provide about 40% of the total minerals, 90% of the total phosphorus, 50% of the total niacin (Vitamin B3), 50% of total lipid, and ...
[20]
The B-Vitamins in Wheat: The Unique Aleurone Layer | Nature
The B-Vitamins in Wheat: The Unique Aleurone Layer · Article PDF · References · Author information · Rights and permissions · About this article · This article ...
[21]
Rice with Multilayer Aleurone: A Larger Sink for Multiple Micronutrients
Dec 13, 2021 · Rice aleurone (bran) contributes to about 40% (39–41%) of total non-starch lipids that mainly consist of TAG and PC, while starchy endosperm ...
[22]
Microbial Degradation of Whole-Grain Complex Carbohydrates and ...
The cell wall polysaccharides of the aleurone, although part of the endosperm, are largely insoluble, in contrast to the cell wall polysaccharides of the ...
[23]
Protein Bodies - an overview | ScienceDirect Topics
Phytin globoids are also present in protein bodies of other dicotyledonous seeds and in aleurone cell protein bodies of cereals. The different routes, taken by ...
[24]
Protein bodies from hemp seeds: Isolation, microstructure and ...
The structure consisted of a protein crystalloid and several phytin globoids, all surrounded by a proteinaceous matrix and a single membrane. Globulin edestin ...
[25]
Endosperm development in Brachypodium distachyon - PMC
Nov 11, 2010 · The number of cell layers in the aleurone is characteristic of the cereal species, with wheat, rye, oats, maize, and sorghum having a single ...
[26]
Linking anthocyanin diversity, hue, and genetics in purple corn - PMC
Kernel anthocyanin content has long been studied in maize due to its easily observable phenotype, but most research to date has focused on kernels with ...
[27]
Characterization and functional biology of the soybean aleurone layer
Dec 13, 2018 · In this paper we describe the morphology and composition of the persistent single-cell aleurone layer that derives from the endosperm of developing soybean ...
[28]
The fine structure of aleurone cells in the soybean seed coat
The aleurone is a tissue lining the embryo sac and consists of a single layer of cells attached to the aerenchyma of the seed coat proper. During seed fill, ...
[29]
Arabidopsis Aleurone Layer Responds to Nitric Oxide, Gibberellin ...
The aleurone layer of Arabidopsis also responds to NO as part of the dormancy loss process, but it is not known if cereal aleurone layers respond likewise.
[30]
Spatial and Temporal Mapping of Key Lipid Species in Brassica ...
The Seed Coat/Aleurone Layer Has a Distinct Lipid Composition. Of all the tissue types analyzed, the seed coat/aleurone layer stood out as being the most ...
[31]
The Arabidopsis aleurone layer responds to nitric oxide, gibberellin ...
The Arabidopsis aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy.
[32]
The aleurone layer of cereal grains: Development, genetic ...
Feb 12, 2025 · This layer consists of a few cell layers and serves as an intermediary between the nutrient-dense aleurone and the carbohydrate-rich starchy.
[33]
Nuclear endosperm development in cereals and Arabidopsis thaliana
Issue date 2004. PMC Copyright notice. PMCID: PMC2643391 PMID: 15010513. Full Text. The Full Text of this article is available as a PDF (305.3 KB). Selected ...
[34]
Two maize END-1 orthologs, BETL9 and BETL9like, are transcribed ...
May 5, 2014 · The BETL9 gene is exclusively transcribed in the basal endosperm transfer cell layer during seed development since 10 days after pollination.
[35]
Aleurone. | Maize kernel development - CABI Digital Library
The aleurone cell layer forms at the surface of the endosperm and is present in seeds of most flowering plants.Missing: divisions | Show results with:divisions
[36]
Programmed cell death (PCD): an essential process of cereal seed ...
The aleurone layer, the only endosperm tissue that remains alive in mature cereal seeds, shows a high sensitivity to gibberellins.
[37]
Positional cues specify and maintain aleurone cell fate in maize ...
Sep 15, 2000 · The aleurone and starchy endosperm share a common lineage throughout development indicating that positional cues specify aleurone fate. Mutants ...
[38]
Cereal Endosperms: Development and Storage Product Accumulation
May 20, 2022 · The development of cereal endosperms progresses through coenocytic nuclear division, cellularization, aleurone and starchy endosperm ...
[39]
Globoids and Phytase: The Mineral Storage and Release System in ...
Oct 12, 2020 · The phytate-rich tissues also contains globoids. Barley (Hordeum vulgare L.) globoids are found in the protein storage vacuole of the aleurone ...
[40]
Cytological structures and physiological and biochemical ...
Aged seeds lose viability and show low germination potential (GP), germination rate (GR), germination index (GI) and vigor index (VI) and increased sensitivity ...
[41]
Gibberellin from Barley Embryos - Nature
IN recent years, considerable interest has been shown in the potentialities of the aleurone layer of barley as a site for synthesis of α-amylase in response ...
[42]
Gibberellin Signaling: Biosynthesis, Catabolism, and Response ...
During germination, GA promotes embryo growth and/or reduces the physical restraint imposed by the endosperm and testa that allows radicle protrusion. In ...Missing: nature. | Show results with:nature.
[43]
Cell wall degradation is required for normal starch mobilisation in ...
Sep 13, 2016 · Endosperm cell walls are a potential barrier to the diffusion of hydrolytic enzymes from the aleurone and scutellum into the endosperm. During ...
[44]
Maize Grain Germination Is Accompanied by Acidification of ... - MDPI
Jul 8, 2023 · This enzyme is an electrogenic pump that exports cytosolic protons to the apoplast, which is characterised by a much lower pH value than the ...
[45]
Programmed cell death (PCD): an essential process of cereal seed ...
Jul 9, 2014 · In germinating seeds, both the scutellum and the aleurone layer play essential roles in producing the hydrolytic enzymes for the mobilization of ...
[46]
Programmed cell death in cereal aleurone - PubMed
Cereal aleurone cells are specialized endosperm cells that function to synthesize and secrete hydrolytic enzymes that break down reserves in the starchy ...Missing: maturation | Show results with:maturation
[47]
Regulation of viability and cell death by hormones in cereal aleurone
Aleurone cells die when ROS accumulate and cause oxidative damage to cell membranes. Aleurone cells store large amounts of triglycerides and the conversion of ...
[48]
The Effect of Mashing on Malt Endoproteolytic Activities
During malting and mashing, the proteinases of barley (Hordeum vulgare L.) and malt partially hydrolyze their storage proteins. These enzymes are critical ...
[49]
Dehydrodimers of Ferulic Acid in Maize Grain Pericarp and Aleurone
This is the first report of in vivo evidence that the dehydrodimers of ferulic acid content in pericarp and aleurone tissues may play a role in genotypic ...<|separator|>
[50]
Antioxidant Secondary Metabolites in Cereals: Potential Involvement ...
Resistance to Fusarium depends on the plant ability in preventing initial infection and containing the development of the toxigenic fungi while resistance to ...
[51]
Strategic Distribution of Protective Proteins within Bran Layers ... - NIH
All proteins of the outer layers were enzymes, whose function is to provide direct protection against pathogens or improve tissue strength. The more complex ...<|separator|>
[52]
Seed chitinases - Cambridge University Press
Chitinase expression is often induced by microbial attack and, in fact, many chitinases have been classified as pathogenesis-related proteins of the PR-3,. PR-4 ...<|separator|>
[53]
The potential role of phytochemicals in wholegrain cereals for the ...
May 16, 2013 · Most phytochemicals function as antioxidants in vitro and have the potential to mitigate oxidative stress and inflammation which are implicated ...
[54]
An Abscisic Acid-Induced Protein, HVA22, Inhibits Gibberellin ...
Abstract. Plant HVA22 is a unique abscisic acid (ABA)/stress-induced protein first isolated from barley (Hordeum vulgare) aleurone cells.An Abscisic Acid-Induced... · Results · Arabidopsis Hva22 Also...
[55]
ABA-mediated regulation of rice grain quality and seed dormancy ...
May 27, 2024 · Abscisic acid (ABA) plays a crucial role in promoting plant stress resistance and seed dormancy. However, how ABA regulates rice quality remains ...
[56]
The defective kernel 1 (dek1) gene required for aleurone cell ...
The predicted maize DEK1 protein (2,159 aa residues; Fig. 3B) was identified as a member of the calpain gene superfamily by the presence of a conserved cysteine ...
[57]
The maize dek1 gene functions in embryonic pattern formation and ...
Nov 15, 2002 · Mutants in the maize defective kernel1 (dek1) gene are blocked in embryogenesis and the endosperm is chalky and lacks an aleurone layer.
[58]
The Maize CRINKLY4 Receptor Kinase Controls a Cell-Autonomous ...
This suggests that CR4 may function in the perception of positional cues that specify aleurone cell fate throughout endosperm development (Becraft and Asuncion- ...
[59]
Abscisic Acid and Stress Signals Induce Viviparous1 Expression in ...
Mutations in vp1 result in kernels with reduced sensitivity to ABA, which fail to undergo normal maturation and germinate viviparously (McCarty et al., 1989).
[60]
Viviparous1 Alters Global Gene Expression Patterns through ...
We show that VP1 has a capacity to modify ABA signaling through feed-forward and feedback interactions mediated by members of the ABI5- and ABI1-related gene ...
[61]
Opaque-2 Regulates a Complex Gene Network Associated with Cell ...
Genome-wide analysis of genes regulated by the maize transcription factor Opaque-2 uncovered its functions in regulation of cell differentiation and endosperm ...
[62]
γ-Zeins are essential for endosperm modification in quality ... - PNAS
γRNAi/+ genotype suggests that γ-zeins are essential for restoring protein body density and starch grain interaction in QPM.<|separator|>
[63]
Cloned genes and genetic regulation of anthocyanin biosynthesis in ...
Jan 23, 2024 · Key regulatory genes R1 (B-Peru), C1 (Colorless1) and P1 are involved in the anthocyanin production pathway in maize (Purple1) (Sharma et al., ...
[64]
Identification of the Pr1 Gene Product Completes the Anthocyanin ...
Putative pr1 loss-of-function alleles were identified as kernels with exceptional red aleurone among the darkly purple-pigmented aleurones of sibling progeny.
[65]
https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1310634/full
[66]
https://pmc.ncbi.nlm.nih.gov/articles/PMC3120156/
[67]
ZmPIN1-mediated auxin transport is related to cellular differentiation ...
A model for ZmPIN1-mediated transport of auxin and the related auxin fluxes during maize kernel development is proposed.
[68]
Aleurone cell identity is suppressed following connation in maize ...
Authors. Jane Geisler-Lee , Daniel R Gallie. Affiliation. 1 Department of ... cytokinin can also affect aleurone development. Publication types. Research ...
[69]
ABA Metabolism and Homeostasis in Seed Dormancy and ... - MDPI
Abscisic acid (ABA) is a key hormone that promotes dormancy during seed development on the mother plant and after seed dispersal participates in the control ...
[70]
evidence for Myb transactivation of a high-pI alpha-amylase gene ...
Our results indicate that the GAMyb is the sole GA-regulated transcription factor required for transcriptional activation of the high-pI alpha-amylase promoter.
[71]
Involvement of ethylene and polyamines biosynthesis and ...
Apr 6, 2017 · Plants possess efficient defence mechanisms to overcome environmental stresses. Polyamines (PAs) and ethylene may function as stress messengers ...Results · Atpase Activity In Abdominal... · Ethylene And Acc Analysis