Immature Endosperm Research Articles

In vitro and in vivo biocompatibility of decellularized cellulose scaffolds functionalized with chitosan and platelet rich plasma for tissue engineering applications

This study describes the fabrication of cellulose scaffold (CS) and cellulose-chitosan (CS/CHI) scaffolds from the immature endosperm of Borassus flabellifer (Linn.) (BF) loaded with platelet rich plasma (PRP). Thus, developed scaffolds were evaluated for their physicochemical and mechanical behavior, growth factor release and biological performance. Additionally, in vivo response was assessed in a sub cutaneous rat model to study vascularization, host inflammatory response and macrophage polarization. The results of this study demonstrated that CS and CS/CHI scaffolds with PRP demonstrated favorable physiochemical and morphogical properties. The scaffold groups CS-PRP and CS/CHI-PRP were able to release growth factors in a well sustained manner under physiological conditions. The presence of PRP in cellulosic scaffolds did show significant differences in their behavior when investigated under in vitro studies, where the release of diverse cytokines improved the cellular proliferation and differentiation of osteoblasts. Finally, the PRP enriched scaffolds when studied under in vivo conditions showed increased angiogenesis and re-epithelialization with adequate collagen deposition and tissue remodeling. Our results suggest that besides the conventional carrier systems, this new-generation of plant-based cellulosic scaffolds with/without any modification can serve as a suitable carrier for PRP encapsulation and release, which can be used in numerous tissue regenerative therapies.

Surface Modification of Decellularized Natural Cellulose Scaffolds with Organosilanes for Bone Tissue Regeneration.

The utility of plant tissues as scaffolding materials has been gaining significant interest in recent years owing to their unique material characteristics that are ideal for tissue regeneration. In this study, the degradation and biocompatibility of natural cellulosic scaffolds derived from Borassus flabellifer (Linn.) (BF) immature endosperm was improved by chemical oxidation and surface functionalization processes. Briefly, thus obtained cellulosic scaffolds were sequentially processed via a detergent exchange decellularization process followed by sodium periodate mediated oxidation and organosilane-based surface modification using amino (NH2)-terminated 3-aminopropyltriethoxysilane (APTES) and methyl (CH3)-terminated octadecyltrichlorosilane (OTS). Post oxidation and surface functionalization, the scaffolds showed improved physiochemical, morphological, and mechanical properties. Especially, the swelling capacity, total porosity, surface area, degradation kinetics, and mechanical behavior of scaffold were significantly higher in modified scaffold groups. The biocompatibility analysis demonstrated excellent cellular adhesion, proliferation and differentiation of osteoblasts with an evident upregulation of mineralization. Subcutaneous implantation of these scaffolds in a rat model demonstrated active angiogenesis, enhanced degradation, and excellent biocompatibility with concomitant deposition of a collagen matrix. Taken together, the native cellulosic scaffolds post chemical oxidation and surface functionalization can exclusively integrate the potential properties of native soft tissue with ameliorated in vitro and in vivo support in bone tissue engineering for nonloading bearing applications.

Comparative studies on nutrient content and antidiabetic effects of sugar palm (Borassus flabellifer) fruit pulp & endosperm on rats

• Sugar palm fruit pulp, immature & germinated endosperm are rich with carbohydrate, fiber, zinc and phytochemicals. • Sugar palm fruit is safe for medicinal uses and significantly reduced fasting blood glucose (FBG) levels. • Germinated endosperm showed maximum antidiabetic effects followed by immature endosperm and pulp, respectively. • Both germinated & immature endosperm may restore damaged pancreatic β-cell function. Nutrient contents of sugar palm (Borassus flabellifer) fruit pulp (SPFP) cultivated in Bangladesh are yet to be well-reviewed. Moreover, the nutrient contents of other popularly consumed edible portions of sugar palm fruit, i.e., immature endosperm (IE), and germinated endosperm (GE) are not studied yet. The current study showed that SPFP, IE, and GE were rich in carbohydrate, fiber, sodium, potassium, and zinc. IE contained the highest amount of fiber, while SPFP contained the highest amount of copper. Twenty-five phytochemicals having known antidiabetic effects were investigated for their presence in pulp, immature & germinated endosperm. GE contained the highest number of phytochemicals (23) followed by IE (19) and SPFP (14). Diabetic patients usually avoid edible portions of sugar palm, fearing that these may further deteriorate existing hyperglycemia. In the present study, this suspicion was investigated in alloxan-induced diabetic rats through supplementary feeding of SPFP, IE, & GE in addition to the regular diet for the nine consecutive weeks. Study results clearly showed that SPFP, IE, & GE significantly reduced fasting blood glucose (FBG) levels of experimental rats. GE showed maximum antidiabetic effects followed by IE and SPFP, respectively. GE, and IE returned the FBG levels within normal range by the end of the sixth week but not by the SPFP. Endosperms supplemented diabetic rats maintained the normal FBG levels even after withdrew the supplementary diets. These results suggested that supplemental feeding of the GE and IE to the experimental diabetic rats may restore alloxan damaged pancreatic β-cell function, and the reasons might be the presence of fiber, zinc and phytochemicals content of the endosperm.

Exogenous abscisic acid impacts the development of isolated immature endosperm in bread wheat

Endosperm in cereals such as wheat, is a part of the mature seeds and a valuable source of key substances for humans and animals. For this reason, the development of immature endosperm tissues in planta was the focus of this research. However, it is commonly known that tissue culture conditions can alter the developmental pathway of plant cells and can expose their potency. There is scarce information about research on isolated endosperm in wheat. The development of isolated immature endosperm in the winter bread wheat variety ‘Kobra’, depending on the media composition, is presented in this study. Abscisic acid (ABA) is a key plant growth regulator for proper seed development. The addition of exogenous ABA had a positive impact on the size and ultrastructural features in isolated endosperm, especially of the outer aleurone-like cells. Furthermore, the content of starch in the endosperm cultured on a medium with ABA did not significantly differ from that of caryopsis at the same age, in contrast to soluble carbohydrates. Fluorescein diacetate (FDA) staining and confocal microscopy observation confirmed the viability of the cells from the outer layers. The analysis of internucleosomal fragmentation of DNA in the explants suggests the induction of programmed cell death (PCD) and DNA degradation typical of necrosis. We concluded that the development of isolated immature endosperm in bread wheat depends on the composition of the media. Thus, it could be a model for in vitro studies of this specific storage tissue and its response to culture conditions in bread wheat.

Decellularized natural 3D cellulose scaffold derived from Borassus flabellifer (Linn.) as extracellular matrix for tissue engineering applications

In this study, Borassus flabellifer (Linn.) (BF) immature endosperm was decellularized to produce three dimensional (3D) cellulose scaffolds that can support mammalian 3D cell culture. To this regard, we first evaluated the chemical composition, nutritive profile and pharmacological activities of BF endosperm. The results demonstrated that the BF tissue represented a complex concoction of polysaccharides with intrinsic phyto-ingredients which provide excellent pharmacological properties. Furthermore cellulosic scaffolds (CS) obtained from BF was treated with chitosan to produce cellulose-chitosan (CS/CHI) hybrid scaffolds. The comparative investigation on both scaffolds exhibited adequate swelling with controlled porosity and pore-size distribution. The physiochemical characterization showed reduced biodegradation, improved thermal stability and enhanced compressive strength in CS/CHI group. Biological studies reported favorable adhesion and proliferation of fibroblasts with evident cellular penetration and colonization on the both scaffolds. Taken together, plant derived cellulosic scaffolds could be used as an alternative scaffolding material in regenerative medicine.

Alterations in allocation and composition of lipid classes in Euonymus fruits and seeds.

The spindle tree (Euonymus europaeus L.) is a much-branched deciduous shrub or small tree. Its fruit capsules contain seeds with remarkably high content of oil interesting for industry, especially the 3-acetyl-1,2-diacyl-sn-glycerols (AcDAG) synthesized by a specific acetyl-CoA diacylglycerol acetyltransferase. The distribution and amount of individual triacylglycerols (TAG) and especially acetyl-triacylglycerols (AcDAG) in Euonymus fruit have previously been assigned to specific tissues. Using anatomical and microscopical observations, we studied the fruit morphology, and for the first time, we identified a more detailed allocation of oil bodies in individual tissue structures. Thin layer chromatography separation of extracts from immature and mature fruits confirmed TAG and AcDAG as the most abundant lipid classes in both endosperm and embryo, followed by fatty acids and polar lipids. The abundance of fatty acids was further studied in the TAG and AcDAG fractions using gas chromatography. Data revealed particular FAs in both fractions allocated in tissue-specific manner and/or as indicators of maturation of E. europaeus seeds. While the abundance of cis-vaccenic-, linoleic as well as α-linolenic acids in the AcDAG structures generally drop with maturation in both embryo and endosperm, content of oleic acid increases. Abundance of cis-vaccenic acid in TAG was recorded in immature endosperm. For embryo, the abundance of stearic acid in AcDAG and oleic acid in TAG fraction was distinctive. Deeper understanding of underlying metabolic processes will be essential for targeted metabolic engineering and/or application for oilseed crops.

Anti-hyperglycemic effect of the immature endosperm of sugar palm (Borassus flabellifer) fruit on type 2 diabetes mellitus patients-a case study

AimThis study aimed to investigate the nutrient contents and the anti-hyperglycemic effect of the immature endosperm of sugar palm (IESP) (Borassus flabellifer L.) fruit on type-2 diabetes mellitus (T2DM) patients. MethodsThis is a short type case study where patients (n = 30) with T2DM were randomly selected and fed IESP (100 mL) twice a day after a regular meal and continued this experiment up to 4th weeks. ResultThe mean fasting blood glucose (FBG) level was markedly reduced from 1st week (15.74 mmol/L) to 4th week (10.53 mmol/L) among the patients who had normal body mass index (18.5–24.9). Only 16.67% diabetic patients had irregular FBG levels where 10% were in the previous stages after finishing the experimental period, and exceptionally in the case of 6.67% diabetic patients, this therapeutic juice was unsuccessful because of their irregular intake of insulin. The IESP was more effective on female (p ≤ 0.001) patients than males (p ≤ 0.05). ConclusionThe IESP could be considered as anti-hyperglycemic fruit, and this might be due to its nutrient contents, especially phytochemicals, fiber, sodium, potassium, copper, and zinc.

Somatic embryogenesis and cryopreservation of Stewartia species

Stewartia is a genus of flowering shrubs and trees in the family Theaceae. Stewartia species are native to eastern Asia, with the exception of S. ovata and S. malacodendron, which are indigenous to southeastern North America. Despite having outstanding ornamental value and unique horticultural features, Stewartias are not readily available for landscaping in the horticultural trade due to difficulty with mass propagation. In addition to commercial propagation, there is a need to develop propagation techniques for the conservation of the North American species, which are rare (S. ovata) or endangered (S. malacodendron). This research examined somatic embryogenesis as a means to mass propagate Asian and North American Stewartia species and to provide material for cryopreservation of valuable Stewartia germplasm. By testing a variety of plant growth regulators (PGRs), somatic embryogenesis was induced from immature zygotic embryo explants of seven Stewartia species—five Asian and two North American. Additionally, embryogenic cultures were obtained from three North American cultivars, S. malacodendron ‘Delmarva’, S. ovata ‘Red Rose’, and ‘Royal Purple’. For two Stewartia species, S. ovata and S. sinensis, somatic embryogenesis was induced from immature endosperm. Picloram (0.05 or 0.1 mg/L) and 2,4-dichlorophenoxyacetic (2 or 4 mg/L) were the most effective PGRs for inducing somatic embryogenesis of North American and Asian Stewartia species, respectively. All seven Stewartia species examined produced somatic embryos that converted into plants that could be transferred to the greenhouse. Embryogenic tissue from five Stewartia species were successfully put into cryo-storage and recovered, providing a means of long-term germplasm storage. This is the first report of somatic embryogenesis in the genus Stewartia. This is the first report of somatic embryogenesis from immature zygotic embryos in the genus Stewartia and it was accomplished with seven different species.

Triploid plant regeneration from immature endosperms of Melia azedazach

Melia azedazach, a plant for forestation, is popular in many countries. Development of triploid M. azedazach varieties will provide additional advantages, such as faster growth, higher biomass, and; therefore, increased productivity. In this study, we aimed to develop triploid M. azedarach L. by immature endosperm tissue culture. After 22 days of initiation of cultures, calli of the endosperm were visible. After 50 days cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg/l NAA and 1.0 mg/l BAP, maximum of callus induction rate from the immature endosperm with seed coat was obtained at 55.9%. The highest frequency of shoot induction from endosperm-derived callus was 98% and average of 16.7 shoots per explant on the medium supplemented with 1.5 mg/l BAP and 0.5 mg/l NAA after 42 days. A single shoot was detached from the multi-shoots and transferred to the rooting medium supplemented with 0.5 mg IBA, inducing root formation with 96.6% and with average of 5.8 roots per plantlet after 28 days. The plantlets transferred to polythene hycotrays containing soil and sand (mixture 1:1) in greenhouse showed 100% survival after transplantation. The endosperm-derived plantlets were 100% triploids as evidenced by flow cytometry analysis. Creating triploid M. azedazach plants by regenerating directly from endosperm (3n) described in this work required only 5 months whereas the traditional method of generating triploids through crossing between tetraploid (4n) and diploid (2n) plants could take up to 12 years.

Kultur In Vitro Endosperma, Protokol yang Efisien untuk Mendapatkan Tanaman Triploid secara Langsung

<p>In Vitro Culture of Endosperm: An efficient protocol to<br />propagate triploid plants directly. L. Agus Sukamto.<br />Triploid plants are very vigorous and beneficial since they<br />generally produce seedless fruits, bigger flowers, and produce<br />more volume of wood than the diploid counterparts.<br />The triploid plants can be produced by crossing diploid and<br />tetraploid plants, but this method is cumbersome and takes<br />a long time. In vitro culture of endosperm is an alternative<br />method to produce triploid plants directly. The success of<br />endosperm culture is dependent on many factors, such as<br />maturity of endosperm, presence of the zygotic embryo, culture<br />medium, growth regulators, browning, culture period,<br />an plant species. Generally, a mature endosperm needs an<br />initial association with an embryo to induce cell divisions,<br />while proliferation of an immature endosperms is not<br />dependent on the embryo. Endosperm of most parasitic<br />angiosperms shows direct organogenesis without callus<br />formation. Plants produced from endosperm culture are<br />generally triploid, although some plants possess different<br />ploidy levels.</p>

Locus- and Site-Specific DNA Methylation of 19 kDa Zein Genes in Maize.

An interesting question in maize development is why only a single zein gene is highly expressed in each of the 19-kDa zein gene clusters (A and B types), z1A2-1 and z1B4, in the immature endosperm. For instance, epigenetic marks could provide a structural difference. Therefore, we investigated the DNA methylation of the arrays of gene copies in both promoter and gene body regions of leaf (non-expressing tissue as a control), normal endosperm, and cultured endosperm. Although we could show that expressed genes have much lower methylation levels in promoter regions than silent ones in both leaf and normal endosperm, there was surprisingly also a difference in the pattern of the z1A and z1B gene clusters. The expression of z1B gene is suppressed by increased DNA methylation and activated with reduced DNA methylation, whereas z1A gene expression is not. DNA methylation in gene coding regions is higher in leaf than in endosperm, whereas no significant difference is observed in gene bodies between expressed and non-expressed gene copies. A median CHG methylation (25–30%) appears to be optimal for gene expression. Moreover, tissue-cultured endosperm can reset the DNA methylation pattern and tissue-specific gene expression. These results reveal that DNA methylation changes of the 19-kDa zein genes is subject to plant development and tissue culture treatment, but varies in different chromosomal locations, indicating that DNA methylation changes do not apply to gene expression in a uniform fashion. Because tissue culture is used to produce transgenic plants, these studies provide new insights into variation of gene expression of integrated sequences.

Microtubule-Associated Protein SBgLR Facilitates Storage Protein Deposition and Its Expression Leads to Lysine Content Increase in Transgenic Maize Endosperm.

Maize (Zea mays) seed is deficient in protein and lysine content. Many studies have been made to improve the nutritional quality of maize seeds. Previously, we reported the role of a natural lysine-rich protein gene SBgLR in increasing protein and lysine content. However, how the SBgLR improves lysine and protein content remains unclear. Here, the reasons and possible mechanism for SBgLR in protein and lysine improvement have been analyzed and discussed. Through seed-specific expression of SBgLR, we obtained transgenic maize with the simultaneously increased lysine and protein contents. High-protein and high-lysine characters were stably inherited across generations. The expression of SBgLR in maize kernels increased the accumulation of both zeins and non-zein proteins. Transmission electron microscopy showed that the number of protein bodies (PBs) was increased obviously in SBgLR transgenic immature endosperms with the morphology and structure of PBs unchanged. The proteinaceous matrix was more abundant in transgenic mature endosperms under scanning electron microscopy. The stabilities of zein and lysine-rich non-zein genes were also increased in transgenic endosperms. Finally, the potential application of SBgLR in maize nutrient improvement was evaluated. This study shows that a cytoskeleton-associated protein has potential applicable value in crop nutrient improving, and provided a feasible strategy for improvement of maize grain quality.

Immature Seed Endosperm and Embryo Proteomics of the Lotus (Nelumbo Nucifera Gaertn.) by One-Dimensional Gel-Based Tandem Mass Spectrometry and a Comparison with the Mature Endosperm Proteome.

Lotus (Nelumbo nucifera Gaertn.) seed proteome has been the focus of our studies, and we have recently established the first proteome dataset for its mature seed endosperm. The current study unravels the immature endosperm, as well as the embryo proteome, to provide a comprehensive dataset of the lotus seed proteins and a comparison between the mature and immature endosperm tissues across the seed’s development. One-dimensional gel electrophoresis (SDS-PAGE) linked with tandem mass spectrometry provided a protein inventory of the immature endosperm (122 non-redundant proteins) and embryo (141 non-redundant proteins) tissues. Comparing with the previous mature endosperm dataset (66 non-redundant proteins), a total of 206 non-redundant proteins were identified across all three tissues of the lotus seed. Results revealed some significant differences in proteome composition between the three lotus seed tissues, most notably between the mature endosperm and its immature developmental stage shifting the proteins from nutrient production to nutrient storage.

Divergent properties of prolamins in wheat and maize

Cereal grains are an important nutritional source of amino acids for humans and livestock worldwide. Wheat, barley, and oats belong to a different subfamily of the grasses than rice and in addition to maize, millets, sugarcane, and sorghum. All their seeds, however, are largely devoid of free amino acids because they are stored during dormancy in specialized storage proteins. Prolamins, the major class of storage proteins in cereals with preponderance of proline and glutamine, are synthesized at the endoplasmic reticulum during seed development and deposited into subcellular structures of the immature endosperm, the protein bodies. Prolamins have diverged during the evolution of the grass family in their structure and their properties. Here, we used the expression of wheat glutenin-Dx5 in maize to examine its interaction with maize prolamins during endosperm development. Ectopic expression of Dx5 alters protein body morphology in a way that resembles non-vitreous kernel phenotypes, although Dx5 alone does not cause an opaque phenotype. However, if we lower the amount of γ-zeins in Dx5 maize through RNAi, a non-vitreous phenotype emerges and the deformation on the surface of protein bodies is enhanced, indicating that Dx5 requires γ-zeins for its proper subcellular organization in maize.

Production of triploid plants of papaya by endosperm culture

Triploid papaya (Carica papaya) plants were obtained by immature endosperm culture. Visible callusing of the endosperm occurred 21 days after initiation of cultures. A continuously growing callus was observed and a maximum of 68.7% of callus induction frequency was obtained when immature endosperm with embryo was cultured on Murashige and Skoog (MS) medium containing 6.0 μM 2,4-dichlorophenoxyacetic acid (2,4-D), 2.5 μM α-naphthaleneacetic acid (NAA) and 4.0 μM 6-furfurylamino purine (Kn). Shoot buds were produced when the callus was subcultured on a medium supplemented with 6-benzyladenine (BA) or thidiazuron (TDZ) along with NAA. Shoots were detached from the callus and transferred to the elongation medium supplemented with indole-3-acetic acid (IAA) and BA. The combination of 3.0 μM IAA and 1.5 μM BA was the best in terms of the number of cultures (93.8%) showing axillary shoot proliferation. The addition of 2.0 μM indole-3-butyric acid (IBA) to the 1/2 MS medium was most effective at inducing root formation with 90% of the shoots developing four to five roots. Healthy rooted plantlets were transferred to pots containing sterilized bed soil and perlite (3:1) mixture in the greenhouse and 78% of the micropropagated plants survived transplantation. The leaves from endosperm-derived plants showed larger stomata and more chloroplasts in guard cells than that from the parent plants. Over 75% of the endosperm-derived plants were triploid with chromosome number 2n = 3x = 27.

Differentially expressed microRNAs during solid endosperm development in coconut ( Cocos nucifera L.)

MicroRNAs (miRNAs) are a class of 20–24 nt, endogenously expressed, non-coding RNAs that play important regulatory roles in plants and animals. To identify miRNAs potentially involved in tissue development and compound anabolism, we studied miRNA expression profiles in endosperm of coconut at different developmental stages. Based on the annotation in miRBase (release 10.1), we measured a total of 179 miRNAs in immature (95 expressed miRNAs) and mature tissues (176 expressed miRNAs) using microarrays, respectively. The comparative analyses on miRNA expression profiles between these two groups of tissues showed that 23 miRNAs were up-regulated and nine miRNAs were down-regulated in matured endosperm. We further confirmed the increased expression of four miRNAs and decreased expression of a miRNA in immature endosperm using real-time PCR. Moreover, we computationally predicted the target genes of 32 miRNAs with differential expression ( p < 0.01), and identified the lowest-score targets of six miRNAs. Finally, we discussed the potential functional relevance of several differentially expressed miRNAs.

Systematic sequence analysis and identification of tissue-specific or stress-responsive genes of NAC transcription factor family in rice

NAM, ATAF, and CUC (NAC) transcription factors comprise a large plant-specific gene family and a few members of this family have been characterized for their roles in plant growth, development, and stress tolerance. In this study, systematic sequence analysis revealed 140 putative NAC or NAC-like genes (ONAC) in rice. Phylogenetic analysis suggested that NAC family can be divided into five groups (I-V). Among them, all the published development-related genes fell into group I, and all the published stress-related NAC genes fell into the group III (namely stress-responsive NAC genes, SNAC). Distinct compositions of the putative motifs were revealed on the basis of NAC protein sequences in rice. Most members contained a complete NAC DNA-binding domain and a variable transcriptional regulation domain. Sequence analysis, together with the organization of putative motifs, indicated distinct structures and potential diverse functions of NAC family in rice. Yeast one-hybrid analysis confirmed that 12 NAC proteins representing different motif compositions can bind the NAC core DNA-binding site. Real-time polymerase chain reaction (PCR) analysis revealed 12 genes with different tissue-specific (such as callus, root, stamen, or immature endosperm) expression patterns, suggesting that these genes may play crucial regulatory roles during growth and development of rice. The expression levels of this family were also checked under various abiotic stresses including drought, salinity, and low temperature. A preliminary check based on our microarray data suggested that more than 40 genes of this family were responsive to drought and/or salt stresses. Among them, 20 genes were further investigated for their stress responsiveness in detail by real-time PCR analysis. Most of these stress-responsive genes belonged to the group III (SNAC). Considering the fact that a very limited number of genes of the NAC family have been characterized, our data provide a very useful reference for functional analysis of this family in rice.

Endosperm culture: a novel method for triploid plant production

Triploid nature of endosperm is the characteristic feature of angiosperms and is formed as a result of triple fusion. Present review discusses the morphogenic response and production of triploid plantlets by endosperm culture. Both mature and immature endosperm used for culture initiation responded differently in cultures. A key factor for the induction of cell divisions in mature endosperm cultures is the initial association of embryo but immature endosperms proliferate independent of embryo. In almost all the parasitic angiosperms, endosperm shows a tendency of direct differentiation of organs without prior callusing, whereas in autotrophic taxa the endosperm usually forms callus tissue followed by differentiation of shoot buds, roots or embryos. The endosperm tissue often shows a high degree of chromosomal variations and polyploidy. Mitotic irregularities, chromosome bridges and laggards are the other important characteristics of endosperm tissues. Triploids are usually seed sterile and is undesirable for plants where seeds are commercially useful. However, in cases where seedlessness is employed to improve the quality of fruits as in banana, apple, citrus, grapes, papaya etc. the induction of triploid plants would be of immense use. Triploid plants have more vigorous vegetative growth than their diploid counterparts. Hence, in plants where the vegetative parts are economically useful, triploids are of good use. This review focuses on the progress achieved so far in endosperm culture to obtain triploid plants.

Influence of genotype and texture on zein content in endosperm of maize grains

AbstractThe effect of genotypes and texture on the content of proteins in maize grains was examined by assessing absolute amounts of six protein fractions in the whole endosperms of four wild‐type lines with high protein content and four quality protein maize (QPM) varieties and for hand‐dissected hard and soft endosperm regions from eight other lines. As previously reported for six wild‐type lines and their opaque‐2(o2) versions, zeins were predominant for all genetic backgrounds and all types of endosperms. From these data and others the amounts of zeins and true proteins (crude proteins free of non‐protein nitrogen) in developing and mature endosperms of wild‐type lines were correlated. The data points for zeins from hard endosperms lay between the regression line and the upper limit of confidence area. Those for zeins from soft endosperms were located at the lower part of confidence area and on a level with the points corresponding to the most immature endosperms. Furthermore, some data points for zeins from o2 and QPM samples lay near the lower limit while the others were outside the confidence area. This suggested an initial zein accumulation dependent on the genotype at a low relative rate, followed by an accumulation at higher rate. The conditions used for isolating and quantitating zeins are discussed.

Embryo-specific silencing of a transporter reduces phytic acid content of maize and soybean seeds

Phytic acid in cereal grains and oilseeds is poorly digested by monogastric animals and negatively affects animal nutrition and the environment. However, breeding programs involving mutants with less phytic acid and more inorganic phosphate (P(i)) have been frustrated by undesirable agronomic characteristics associated with the phytic acid-reducing mutations. We show that maize lpa1 mutants are defective in a multidrug resistance-associated protein (MRP) ATP-binding cassette (ABC) transporter that is expressed most highly in embryos, but also in immature endosperm, germinating seed and vegetative tissues. Silencing expression of this transporter in an embryo-specific manner produced low-phytic-acid, high-Pi transgenic maize seeds that germinate normally and do not show any significant reduction in seed dry weight. This dominant transgenic approach obviates the need for incorporating recessive lpa1 mutations to create maize hybrids with reduced phytic acid. Suppressing the homologous soybean MRP gene also generated low-phytic-acid seed, suggesting that the strategy might be feasible for many crops.