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Rice prolamins are categorized into three groups by molecular size (10, 13, or 16 kDa), while the 13 kDa prolamins are assigned to four subgroups (Pro13a-I, Pro13a-II, Pro13b-I, and Pro13b-II) based on cysteine residue content. Since lowering prolamin content in rice is essential to minimize indigestion and allergy risks, we generated four knockout lines using CRISPR-Cas9, which selectively reduced the expression of a specific subgroup of the 13 kDa prolamins. These four mutant rice lines also showed the compensatory expression of glutelins and non-targeted prolamins and were accompanied by low grain weight, altered starch content, and atypically-shaped starch granules and protein bodies. Transcriptome analysis identified 746 differentially expressed genes associated with 13 kDa prolamins during development. Correlation analysis revealed negative associations between genes in Pro13a-I and those in Pro13a-II and Pro13b-I/II subgroups. Furthermore, alterations in the transcription levels of 9 ER stress and 17 transcription factor genes were also observed in mutant rice lines with suppressed expression of 13 kDa prolamin. Our results provide profound insight into the functional role of 13 kDa rice prolamins in the regulatory mechanisms underlying rice seed development, suggesting their promising potential application to improve nutritional and immunological value. [ABSTRACT FROM AUTHOR]

Abstract The quantity and composition of rice proteins play a crucial role in determining taste quality of sake, Japanese rice wine. However, the spatial distribution of proteins within rice grains, especially in endosperm tissue, and the differences between rice varieties remain unclear. Here, we analyzed the crude protein contents and composition ratios of table (Nipponbare and Koshihikari) and genuine sake rice varieties (Yamadanishiki, Gohyakumangoku, Dewasansan, Dewanosato, and Yumenokaori) to elucidate their spatial distribution within the Japonica rice grain endosperm. Seven sake rice varieties were polished over five harvest years using a brewer’s rice-polishing machine. We obtained fractions at 90–70% (the outermost endosperm fraction), 70–50%, 50–30%, and 30–0% (the central region of the endosperm fraction). Yamadanishiki and Dewanosato exhibited considerably lower crude protein contents than the other cultivars. After applying SDS-PAGE, the protein composition, comprising glutelin/total protein (G/TP), prolamin/TP (P/TP), and G/P ratios of these fractions was determined. In white rice (at a 90% rice-polishing ratio), the average ratio of the major protein composition was G/TP 41%, P/TP 21%, and G/P ratios of 1.97. Gohyakumangoku and Yamadanishiki had higher G/TP ratio, while Dewanosato had a lower value. Despite having lower crude protein contents, Yamadanishiki and Dewanosato exhibited significantly varying G/TP ratios. The G/TP ratio markedly varied among rice varieties, particularly in the rice grains’ central region. The 50–30% fraction had the highest P/TP ratio among all tested rice varieties, suggesting spatial differences in P/TP within rice grains. Koshihikari had the lowest P/TP ratio. In addition, the 50–30% fraction had the lowest G/P ratio among all tested rice varieties, with Gohyakumangoku having the highest G/P ratio. Dewanosato had the lowest G/P value, and this value significantly differed from that of Yamadanishiki in the 30–0% fraction. We found substantial differences in protein composition within distinct spatial regions of rice grains, and larger differences among rice varieties were observed in the rice grain’s central region.

The quantity and composition of rice proteins play a crucial role in determining taste quality of sake, Japanese rice wine. However, the spatial distribution of proteins within rice grains, especially in endosperm tissue, and the differences between rice varieties remain unclear. Here, we analyzed the crude protein contents and composition ratios of table (Nipponbare and Koshihikari) and genuine sake rice varieties (Yamadanishiki, Gohyakumangoku, Dewasansan, Dewanosato, and Yumenokaori) to elucidate their spatial distribution within the Japonica rice grain endosperm. Seven sake rice varieties were polished over five harvest years using a brewer's rice-polishing machine. We obtained fractions at 90–70% (the outermost endosperm fraction), 70–50%, 50–30%, and 30–0% (the central region of the endosperm fraction). Yamadanishiki and Dewanosato exhibited considerably lower crude protein contents than the other cultivars. After applying SDS-PAGE, the protein composition, comprising glutelin/total protein (G/TP), prolamin/TP (P/TP), and G/P ratios of these fractions was determined. In white rice (at a 90% rice-polishing ratio), the average ratio of the major protein composition was G/TP 41%, P/TP 21%, and G/P ratios of 1.97. Gohyakumangoku and Yamadanishiki had higher G/TP ratio, while Dewanosato had a lower value. Despite having lower crude protein contents, Yamadanishiki and Dewanosato exhibited significantly varying G/TP ratios. The G/TP ratio markedly varied among rice varieties, particularly in the rice grains' central region. The 50–30% fraction had the highest P/TP ratio among all tested rice varieties, suggesting spatial differences in P/TP within rice grains. Koshihikari had the lowest P/TP ratio. In addition, the 50–30% fraction had the lowest G/P ratio among all tested rice varieties, with Gohyakumangoku having the highest G/P ratio. Dewanosato had the lowest G/P value, and this value significantly differed from that of Yamadanishiki in the 30–0% fraction. We found substantial differences in protein composition within distinct spatial regions of rice grains, and larger differences among rice varieties were observed in the rice grain's central region. [ABSTRACT FROM AUTHOR]

Key message: We generated a new Koshihikari rice line with a drastically reduced content of glutelin proteins and higher lodging resistance by using new and conventional plant breeding techniques. Using CRISPR/Cas9-mediated genome editing, we generated mutant rice with drastically decreased contents of major glutelins. A Koshihikari rice mutant line, a123, lacking four glutelins (GluA1, GluA2, GluB4, and GluB5) was used as a host, and another five major glutelin genes (GluA3, GluB1a, GluB1b, GluB2, and GluC) were knocked out through two iterations of Agrobacterium-mediated transformation. Mutant seeds were deficient in the GluA family, GluB family, and GluC, and the line obtained was named GluABC KO. Glutelin content was much lower in GluABC KO than in the existing low-glutelin rice mutant LGC-1. A null segregant of GluABC KO was selected using new-generation sequencing and backcrossing, and the sd-1 allele for the semi-dwarf trait was introduced to increase lodging resistance. [ABSTRACT FROM AUTHOR]

The glutelins are a family of abundant plant proteins comprised of four glutelin subfamilies (GluA, GluB, GluC, and GluD) encoded by 15 genes. In this study, expression of subsets of rice glutelins were suppressed using CRISPR-Cas9 gene-editing technology to generate three transgenic rice variant lines, GluA1, GluB2, and GluC1. Suppression of the targeted glutelin genes was confirmed by SDS-PAGE, Western blot, and q-RT-PCR. Transgenic rice variants GluA1, GluB2, and GluC1 showed reduced amylose and starch content, increased prolamine content, reduced grain weight, and irregularly shaped protein aggregates/protein bodies in mature seeds. Targeted transcriptional profiling of immature seeds was performed with a focus on genes associated with grain quality, starch content, and grain weight, and the results were analyzed using the Pearson correlation test (requiring correlation coefficient absolute value ≥ 0.7 for significance). Significantly up- or down-regulated genes were associated with gene ontology (GO) and KEGG pathway functional annotations related to RNA processing (spliceosomal RNAs, group II catalytic introns, small nucleolar RNAs, microRNAs), as well as protein translation (transfer RNA, ribosomal RNA and other ribosome and translation factors). These results suggest that rice glutelin genes may interact during seed development with genes that regulate synthesis of starch and seed storage proteins and modulate their expression via post-transcriptional and translational mechanisms. [ABSTRACT FROM AUTHOR]

Rice grain quality is a multifarious attribute mainly governed by multiple nutritional factors. Grain protein is the central component of rice grain nutrition dominantly affecting eating–cooking qualities. Grain protein content is quantitatively influenced by its protein fractions. Genetic quantification of five protein fractions—albumins, globulins, prolamins, glutelin, and grain protein content—were evaluated by exploiting two BC3F2 mapping populations, derived from Kongyu131/TKM9 (population-I) and Kongyu131/Bg94-1 (population-II), which were grown in a single environment. Correlation studies among protein fractions and grain protein content were thoroughly investigated. A genetic linkage map was developed by using 146 single sequence repeat (SSR) markers in population-I and 167 markers in population-II. In total, 40 QTLs were delineated for five traits in both populations. Approximately 22 QTLs were dissected in population-I, derived from Kongyu131/TKM9, seven QTLs for albumin content, four QTLs for globulin content, three QTLs for prolamin content, four QTLs for glutelin content, and four QTLs for grain protein content. In total, 18 QTLs were detected in population-II, derived from Kongyu131/Bg94-1, five QTLs for albumin content, three QTLs for globulin content, four QTLs for prolamin content, two QTLs for glutelin content, and four QTLs for grain protein content. Three QTLs, qAlb7.1, Alb7.2, and qGPC7.2, derived from population-II (Kongyu131/Bg94-1) for albumin and grain protein content were successfully validated in the near isogenic line (NIL) populations. The localized chromosomal locus of the validated QTLs could be helpful for fine mapping via map-based cloning to discover underlying candidate genes. The functional insights of the underlying candidate gene would furnish novel perceptivity for the foundation of rice grain protein content and trigger the development of nutritionally important rice cultivars by combining marker-assisted selection (MAS) breeding. [ABSTRACT FROM AUTHOR]

The retrogradation of rice starch is the major factor that restricts its application. Recent studies have suggested that extrusion combined with glutelin has an obvious inhibitory effect on the retrogradation of rice starch. This study was executed in order to clarify the influence of extrusion parameters including screw speed, extrusion temperature, raw material moisture content and mass ratio of rice starch to glutelin on the retrogradation properties of rice starch-glutelin mixed system. Furthermore, how extrusion treatment could delay the regeneration of the mixed system was analyzed using a rapid viscosity analyzer (RVA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, low-field nuclear magnetic resonance (LF-NMR), scanning electron microscopy (SEM), laser scanning confocal microscopy (LSCM) and a rheometer. The results showed that the most pronounced retarding effect on the retrogradation of the mixed system was observed when the screw speed was 300 r/min, the extrusion temperature was 90 ℃, the moisture content of the raw material was 34%, and the starch/protein ratio (material ratio) was 91:9. Extrusion treatment significantly decreased the peak viscosity, disintegration value and retrogradation value of the composite system from (3 005.00 ± 25.00), (1 193.00 ± 6.00), and (164.33 ± 3.51) cP to (429.00 ± 5.00), (213.00 ± 3.00) and (27.05 ± 0.14) cP, respectively (P < 0.05), and reduced the relative crystallinity from (20.18 ± 0.13)% to (2.17 ± 0.43)%. Moreover, the endothermic peak of the mixture disappeared, and the ratio between the peak intensities at 1 047 and 1 022 cm−1 in the infrared spectra was decreased significantly to 0.43 ± 0.08 (P < 0.05). After extrusion treatment, the microstructure became more uniform and compact, the water retention property was enhanced, the shear stress was decreased, the hysteresis loop area was increased, and the storage modulus (G’) and the loss modulus (G”) were decreased, indicating good resistance to retrogradation. The results of this study provide a theoretical reference for the application of extrusion treatment in delaying the retrogradation of rice starch–glutelin mixed system.

Rice prolamins are categorized into three groups by molecular size (10, 13, or 16 kDa), while the 13 kDa prolamins are assigned to four subgroups (Pro13a-I, Pro13a-II, Pro13b-I, and Pro13b-II) based on cysteine residue content. Since lowering prolamin content in rice is essential to minimize indigestion and allergy risks, we generated four knockout lines using CRISPR-Cas9, which selectively reduced the expression of a specific subgroup of the 13 kDa prolamins. These four mutant rice lines also showed the compensatory expression of glutelins and non-targeted prolamins and were accompanied by low grain weight, altered starch content, and atypically-shaped starch granules and protein bodies. Transcriptome analysis identified 746 differentially expressed genes associated with 13 kDa prolamins during development. Correlation analysis revealed negative associations between genes in Pro13a-I and those in Pro13a-II and Pro13b-I/II subgroups. Furthermore, alterations in the transcription levels of 9 ER stress and 17 transcription factor genes were also observed in mutant rice lines with suppressed expression of 13 kDa prolamin. Our results provide profound insight into the functional role of 13 kDa rice prolamins in the regulatory mechanisms underlying rice seed development, suggesting their promising potential application to improve nutritional and immunological value.

Sorghum glutelin is a storage protein, presenting in the grain of rice, corn, and other cereal crops, it is the general term of the proteins insoluble in pure water, neutral salt solution or alcohol, but soluble in dilute alkali or dilute acid. In order to provide a basis for further study on the function of sorghum glutelin and improvement of grain quality, in this study, the DNA and amino acid sequence data of sorghum glutelin were obtained through the BLAST Phytozome database, and the SbGLUA1(Sobic. 001G143700), SbGLUA2(Sobic. 009G017600), and SbGLUB4(Sobic. 009G007100) genes were identified by bioinformatics methods, and the information of glutelin gene family, gene structure, phylogenetic tree, the expression of glutelin in different genotypes and tissues, as well as the physicochemical properties, transmembrane, secondary and tertiary structure, and protein interaction of glutelin proteins were analyzed. The results showed that most of the glutelin proteins were not secretory proteins, and were hydrophilic proteins with poor fluidity, the secondary structure of SbGLUB4 was mainly random coil and α -helix. The gene domain analysis of glutelin showed that most proteins were conserved. Sorghum glutelin had high homology with wheat gluten. SbGLUB4 was expressed specifically in seeds and increased with seed maturity. There were differences between varieties, that of IS22204 was slightly higher than that of Laohanye; SbGLUA2 was expressed in seeds, spikes, and other organs. The STRING prediction interaction protein showed that SbGLUB4 interacted with several seed storage protein result genes and regulatory genes(such as MYB and bHLH), while SbGLUA2 interacted with DNA helicase and recombinase enzyme, inferring that the function changed. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nutritional grain quality is mainly influenced by the protein fraction content and grain protein content. Quantitative trait loci (QTL) mining for five traits, about 245 and 284 BC3F3 individual families of two introgression line (IL) populations were derived from Kongyu 131/Cypress (population-I) and Kongyu 131/Vary Tarva Osla (population-II), respectively. A genetic linkage map was developed using 127 simple sequence repeat (SSR) markers in population-I and 119 SSR markers in population-II. In total, 20 and 5 QTLs were detected in population-I and population-II, respectively. About twenty QTLs were mapped in population-I: five QTLs for albumin, seven QTLs for globulin, six QTLs for prolamin, one QTL for glutelin, and one QTL for grain protein content. In total, five QTLs were mapped in population-II: one QTL for albumin and four QTLs for grain protein content. Out of 25 QTLs, 19 QTLs exhibit co-localization with the previously reported QTLs. QTL-like qGPC7.3 was delineated for total protein content. This QTL was derived from population-I and was successfully validated in NILs (near-isogenic lines). The grain protein phenotype showed a significant variation between two NILs. This investigation serves as groundwork for additional cloning of nutritional quality-related genes in rice grains. [ABSTRACT FROM AUTHOR]

The current study aimed to explore the dynamic binding process and molecular mechanism for the non-covalent interaction between sinapic acid (SA) and rice bran glutelin (RBG). Fluorescence spectroscopy was used to investigate the mechanism of fluorescence quenching, the number of binding sites and thermodynamic parameters. Further, the binding process of complex formation and the underlying molecular mechanism were revealed by the combination of homology modeling, molecular docking and molecular dynamic simulations. Fluorescence study showed that SA quenched the intrinsic fluorescence of RBG via static mode, indicating the formation of SA-RBG complex. The number of binding site was about 1. Thermodynamic parameters suggested that the SA could bind with RBG spontaneously, which was predominately driven by hydrophobic interactions. Molecular docking revealed that there were five potent binding sites on RBG for SA. Further molecular dynamic simulation revealed that SA could not only bind stably at binding site C2 but also exhibited the lowest binding free energy, suggesting that C2 was the most favorable binding cavity among the five predicted binding sites. Furthermore, molecular dynamic simulation results including the radius of gyrate, root mean square deviation and root mean square fluctuation further validated the binding stable between SA and RBG. The decomposition of binding free energy to per amino acid residue combined with binding mode analysis indicated that six key residues (including Ile131, Ile90, Trp149, Gln261, Tyr151 and Tyr102) of RBG and two methoxy groups of SA played critical roles in the binding process between SA an RBG. The above results would provide theoretical basis for the application and development of SA-RBG complex as functional ingredients.

Copyright of Journal of Shenyang Agricultural University is the property of Journal of Shenyang Agricultural University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of a high-power ultrasound (50, 75, and 100% amplitude) of 29.29, 38.08, and 52.72 W power levels on selected physicochemical, functional, and in vitro digestibility of two proso millet protein fractions (prolamin and glutelin) for 5 and 10 min was investigated. The protein was extracted from two proso millet cultivar (dawn and Plateau). The results show that the solubility and digestibility of the prolamin and glutelin fractions were significantly (P < 0.05) enhanced as compared to the native protein fractions. On average, about 30, 58, 55, and 28% increase in in vitro digestibility. Similarly, the solubility increased with increasing ultrasound power and treatment time for the protein fractions. For instance, there was a 169, 191, 235% increase in solubility over the native fraction for Dawn prolamin for power levels of 29.29, 38.08, and 52.72 W at 5 min. treatment time. The foaming capacity was observed to only increase significantly with a long treatment time for both the prolamin and glutelin fractions while the emulsion activity index was observed to increase slightly after 5 min of ultrasound treatment but not after 10 min of treatment. The multi-modal distribution of the particle sizes of the proteins could explain the differential behavior in its foaming and emulsion functionality. This study established ultrasound treatment as a method for modifying functional properties of proso millet proteins. [ABSTRACT FROM AUTHOR]

The glutelins are a family of abundant plant proteins comprised of four glutelin subfamilies (GluA, GluB, GluC, and GluD) encoded by 15 genes. In this study, expression of subsets of rice glutelins were suppressed using CRISPR-Cas9 gene-editing technology to generate three transgenic rice variant lines, GluA1, GluB2, and GluC1. Suppression of the targeted glutelin genes was confirmed by SDS-PAGE, Western blot, and q-RT-PCR. Transgenic rice variants GluA1, GluB2, and GluC1 showed reduced amylose and starch content, increased prolamine content, reduced grain weight, and irregularly shaped protein aggregates/protein bodies in mature seeds. Targeted transcriptional profiling of immature seeds was performed with a focus on genes associated with grain quality, starch content, and grain weight, and the results were analyzed using the Pearson correlation test (requiring correlation coefficient absolute value ≥ 0.7 for significance). Significantly up- or down-regulated genes were associated with gene ontology (GO) and KEGG pathway functional annotations related to RNA processing (spliceosomal RNAs, group II catalytic introns, small nucleolar RNAs, microRNAs), as well as protein translation (transfer RNA, ribosomal RNA and other ribosome and translation factors). These results suggest that rice glutelin genes may interact during seed development with genes that regulate synthesis of starch and seed storage proteins and modulate their expression via post-transcriptional and translational mechanisms.

Reconstituted rice produced by extrusion has been attracted attention due to nutritional fortification and convenient production. Nevertheless, how to achieve desirable qualities and physicochemical properties of reconstituted rice nearly to natural rice by regulating extrusion process parameters is difficult. Herein, rice starch/glutelin mixture as raw material of reconstituted rice was extruded at varying extrusion conditions. Specific mechanical energy (SME) and sectional expansion index (SEI) dropped with rise in density (R2 = 0.9117 and 0.8207). Solubility was enhanced with increase in product temperature (R2 = 0.9085), color darkened and shifted to reddish and yellowish as extrusion temperature increased (R2 = 0.8577). These trends were well fitted by sigmoid models. Furthermore, SME enhanced hydrophobic and electrostatic interactions between rice starch and glutelin and caused the reduction in crystallinity and thermal stability, promoting the formation of a bi-continuous matrix of protein aggregates with rice starch. The obtained results can be applied to guide the production of reconstituted rice with desirable qualities. [Display omitted] • Relationship between physicochemical and structural features and extrusion parameters was investigated. • Interaction mechanism of rice starch/glutelin mixture during extrusion process was revealed. • The density of E -RS/G-Cs dropped with increase in SME (R2 = 0.9117). • Solubility index was enhanced with increase in product temperature in the E-RS/G-Cs (R2 = 0.9085). • SME promoted the formation of a bi-continuous matrix of protein aggregates with rice starch. [ABSTRACT FROM AUTHOR]

Enhancing the solubility of rice glutelin in neutral aqueous solution is the prerequisite for the development of rice protein drinks and ingredients. Herein, glutelin was first dissolved in an aqueous solution of pH 12, and then heated at 121 °C for 20 min. The results showed that the solubility of glutelin increased from 2.55 mg/mL to 20.7 mg/mL at pH 7. The size of glutelin aggregates at pH 7 decreased from 900 nm to 400 nm after high temperature treatment (HTT), which was confirmed by atomic force microscopy. The results of small angle X-ray scattering showed that HTT induced the conformational unfolding of glutelin, and the protein in the aggregate was rod like shape as well as the mean square rotation radius decreased from 64.9 to 54.8 Å. Furthermore, Raman spectrum results also agree with the unfolding of glutelin conformation, which was mainly reflected in the changes of tyrosine and tryptophan residues, as well as the decreasing of α-helix content and increasing of β-sheet content. After being freeze-dried, HTT glutelin has a re-solubilization capacity of 15.48 mg/mL in pH 7 aqueous solution, which was superior to that of spray dried glutelin powder (pH 7, 9.19 mg/mL). [ABSTRACT FROM AUTHOR]

Nutritional grain quality is mainly influenced by the protein fraction content and grain protein content. Quantitative trait loci (QTL) mining for five traits, about 245 and 284 BC3F3 individual families of two introgression line (IL) populations were derived from Kongyu 131/Cypress (population-I) and Kongyu 131/Vary Tarva Osla (population-II), respectively. A genetic linkage map was developed using 127 simple sequence repeat (SSR) markers in population-I and 119 SSR markers in population-II. In total, 20 and 5 QTLs were detected in population-I and population-II, respectively. About twenty QTLs were mapped in population-I: five QTLs for albumin, seven QTLs for globulin, six QTLs for prolamin, one QTL for glutelin, and one QTL for grain protein content. In total, five QTLs were mapped in population-II: one QTL for albumin and four QTLs for grain protein content. Out of 25 QTLs, 19 QTLs exhibit co-localization with the previously reported QTLs. QTL-like qGPC7.3 was delineated for total protein content. This QTL was derived from population-I and was successfully validated in NILs (near-isogenic lines). The grain protein phenotype showed a significant variation between two NILs. This investigation serves as groundwork for additional cloning of nutritional quality-related genes in rice grains.

To explore the effect and its mechanism of alkali-assisted phosphorylation on the functional properties of Camellia Oleifera seeds cake glutelin (CSCG), CSCG was treated with different concentration of sodium trimetaphosphate (STMP, 1.0, 2.0, 3.0, 4.0, and 5%, w/v) in different pH environment (3.0, 5.0, 7.0, 9.0, and 11.0). The results showed that alkali assist improved the phosphorylation degree of CSCG, and the optimum pH value is 9.0. FT-IR and XPS confirmed the successful modification of phosphate groups on CSCG through covalent interaction. Alkali-assisted phosphorylation decreased the particle size and increased electronegativity of CSCG, as well as changed in its surface hydrophobicity, crystallinity, and intrinsic fluorescence. All these changes of protein structure triggered by alkali-assisted phosphorylation led to the improvement of water solubility, water/oil absorption capacity, emulsifying ability, foamability, and in vitro digestibility of CSCG. This work could provide a theoretical basis for industrial production of CSCG with excellent functional properties.

SUMMARY: Rice eating and cooking quality (ECQ) is a major concern of breeders and consumers, determining market competitiveness worldwide. Rice grain protein content (GPC) is negatively related to ECQ, making it possible to improve ECQ by manipulating GPC. However, GPC is genetically complex and sensitive to environmental conditions; therefore, little progress has been made in traditional breeding for ECQ. Here, we report that CRISPR/Cas9‐mediated knockout of genes encoding the grain storage protein glutelin rapidly produced lines with downregulated GPC and improved ECQ. Our finding provides a new strategy for improving rice ECQ. [ABSTRACT FROM AUTHOR]

Summary: Defatted lentil seed flour proteins were separated into their constituent albumin (ALB), globulin (GLB) and glutelin (GLT) fractions followed by determination of their structural and functional properties. The GLB fraction demonstrated superior solubility (84%–100%) at acidic and alkaline pH values when compared to the lower values for ALB and GLT. Amino acid composition analysis showed lower contents of hydrophobic and sulphur‐containing residues for GLB. However, GLB had the highest in vitro protein digestibility, which may be due to lower contents of rigid secondary structure fractions like the β‐sheet and β‐turns. In contrast, water and oil holding capacities as well as gelling ability were better for GLT and ALB than GLB. The GLT fraction formed very poor emulsions at pH 3 and 5 but emulsification was significantly (p < 0.05) improved (smaller oil droplets) at pH 7 and 9. Foaming capacity was strongest for GLB, especially at pH 5, 7 and 9 where increase in protein concentration had a negative effect on foam formation. Overall, the protein type and pH of the environment had stronger effects on emulsion and foaming properties than the protein concentration. [ABSTRACT FROM AUTHOR]

Jatropha curcas seeds are a suitable source of oil for biofuel, among other use. A protein‐rich meal is obtained after oilseed extraction. The goals of this study were to determine the physicochemical and functional properties of a nontoxic genotype of J. curcas defatted meal (JCDM) and the seed storage protein fractions to identify future applications. Both glutelin and globulin were the predominant protein fractions obtained from JCDM (42.03 and 20.17 g/100 g of protein, respectively). Leucine, phenylalanine + tyrosine, and histidine content of JCDM and protein fractions met the Food and Agriculture Organization/World Health Organization recommendation for children. The protein solubility (PS) profiles showed minimum values (5.3%–59.7%) at pH 5–6 and maximum at pH 2 (79.7%–81.6%) and above pH 10 (84.6%–89.8%). These findings suggest that JCDM proteins could be used in the formulation of juice or protein‐based beverages. All the proteins showed the highest values for foam expansion (231%–285%) at pH 9. JCDM and the albumin fraction formed highly stable foams at pH 9, while the globulin and glutelin foams were stable at pH 3 and 2, respectively. Protein with stable foams, like those from jatropha are suitable for application in ice cream, mousse, among others. The emulsion activity index had similar behavior as foam expansion, but did not follow a specific trend. Thus, the proteins are suitable for use in salad dressing, sausages, comminuted meats, and mayonnaise. Taken together, JCDM protein and its soluble protein fractions have strong promise as alternative proteins for food structuring. [ABSTRACT FROM AUTHOR]

Abstract Background Rice is not only an essential food but also a source of high quality protein. Polyploidy is an evolutionary trajectory in plants, and enhancing glutelin by polyploidization is an attractive strategy for improving the nutritional value of rice seeds and presents a great potential for enhancing the commercial value of rice. Elucidating the mechanisms underlying glutelin synthesis and accumulation in tetraploid rice is of great significance. Results To enhance the nutritional value of rice, we developed tetraploid rice and evaluated the contents of various nutrient elements in mature seeds. The results revealed a significant increase in protein contents, including the total seed storage proteins, glutelins, and amino acids in tetraploid rice when compared with those in diploid rice. Tandem mass tag-based quantitative proteomic analyses of seeds revealed that glutelins regulated by several glutelin genes in 9311-4x were significantly up-regulated (≥1.5-fold), which was further verified by immunoblot analyses. In addition, temporal expression patterns of various glutelin subunits in different rice lines were investigated. The results revealed significant differences in the expression patterns between diploid and tetraploid rice seeds. Cytohistological analyses results revealed that the thickness of aleurone cell layers increased significantly by 32% in tetraploid rice, the structures of protein storage vacuoles (PSVs) in sub-aleurone cells were more diverse and abundant than those of diploid rice. Temporal expression and proteomic analyses results revealed that protein disulfide isomerase-like 1–1 expression levels were higher in tetraploid rice than in diploid rice, and that the gene responded to oxidative folding with increased levels of proglutelin and appropriate distribution of seed glutelins in tetraploid rice. Conclusion The results of the present study revealed that polyploidization increased glutelin content by influencing glutelin biosynthesis, transport, and deposition, while variations in glutelin accumulation between tetraploid and diploid rice were largely manifested in the initial time, duration, and relative levels of various glutelin gene expressions during seed filling stages. These findings provide novel insights into improving the protein quality and nutritional value of rice seeds by polyploid breeding.

Summary: Ultrasound was applied to facilitate starch–protein separation in ultrasound‐assisted laboratory‐scale corn wet‐milling. Changes to the molecular structure of glutelin and zein in the corn gluten meal treated by sonication were investigated to explore their roles in the release of starch. Sonication (130 to 200 W, 15 to 60 min) was found to cause the unfolding of the glutelin, as demonstrated in the decrease in disulphide bonds (SS) content, α‐helix and β‐turn, and the increase in free sulfhydryl (SH) content, β‐sheet and random coil. Furthermore, the solubility, surface hydrophobicity and fluorescence intensity of the glutelin (200 W/60 min) increased by 141.75, 109.18 and 186.01%, respectively, while its denaturation temperature (Td) and endothermic enthalpy (∆H) decreased by 7.43 and 21.51%. Compared with control zein, after 60 min sonication at 200 W, the SS content and α‐helix of the zein were found to have decreased by 20.68 and 19.14%, and its SH and random coil increased by 26.61 and 18.21%. Accordingly, the solubility, surface hydrophobicity and fluorescence intensity of zein increased by 54.03, 6.85 and 84.62%, and its Td and ∆H decreased by 5.76 and 4.19%. It was, thus, concluded that glutelin is more sensitive than zein to sonication and that the unfolding of glutelin is critical to the release of starch granules. [ABSTRACT FROM AUTHOR]

Seed reserve mobilization is considered a post-germination process; however, seed storage protein mobilization occurs during germination. Thus, the knowledge of seed protein composition is important to understand various processes during germination, and it be associated with seed vigor. Therefore, this study aimed to characterize landrace genotypes of common bean (Phaseolus vulgaris) through fractionation of seed storage proteins during germination and to verify the association between seed protein composition and seed vigor. Genotypes of the highest (55 and 81) and lowest (23 and 50) physiological quality were selected. Protein content analysis, profiling, and characterization were performed by combining different hydration times. Mass spectrometry involving in-gel digestion and MALDI-ToF analysis was employed for the qualitative identification of proteins. Glutelin extraction detected the enzyme lipoxygenase in genotypes 55 and 81 alone. In plants, this enzyme may be involved in diverse physiological processes, including growth and development, pest resistance, senescence, and response to wounding. In the process of germination, lipoxygenase removes reactive oxygen species during reserve mobilization; therefore, lipoxygenase may be a candidate biochemical marker for high-vigor genotypes. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is the most important food crop for at least half of the world's population. Due to improved living standards, the cultivation of high‐quality rice for different purposes and markets has become a major goal. Rice quality is determined by the presence of many nutritional components, including seed storage proteins (SSPs), which are the second most abundant nutrient components of rice grains after starch. Rice SSP biosynthesis requires the participation of multiple organelles and is influenced by the external environment, making it challenging to understand the molecular details of SSP biosynthesis and improve rice protein quality. In this review, we highlight the current knowledge of rice SSP biosynthesis, including a detailed description of the key molecules involved in rice SSP biosynthetic processes and the major environmental factors affecting SSP biosynthesis. The effects of these factors on SSP accumulation and their contribution to rice quality are also discussed based on recent findings. This recent knowledge suggests not only new research directions for exploring rice SSP biosynthesis but also innovative strategies for breeding high‐quality rice varieties. [ABSTRACT FROM AUTHOR]

Seed reserve mobilization is considered a post-germination process; however, seed storage protein mobilization occurs during germination. Thus, the knowledge of seed protein composition is important to understand various processes during germination, and it be associated with seed vigor. Therefore, this study aimed to characterize landrace genotypes of common bean (Phaseolus vulgaris) through fractionation of seed storage proteins during germination and to verify the association between seed protein composition and seed vigor. Genotypes of the highest (55 and 81) and lowest (23 and 50) physiological quality were selected. Protein content analysis, profiling, and characterization were performed by combining different hydration times. Mass spectrometry involving in-gel digestion and MALDI-ToF analysis was employed for the qualitative identification of proteins. Glutelin extraction detected the enzyme lipoxygenase in genotypes 55 and 81 alone. In plants, this enzyme may be involved in diverse physiological processes, including growth and development, pest resistance, senescence, and response to wounding. In the process of germination, lipoxygenase removes reactive oxygen species during reserve mobilization; therefore, lipoxygenase may be a candidate biochemical marker for high-vigor genotypes.

Background: Rice is not only an essential food but also a source of high quality protein. Polyploidy is an evolutionary trajectory in plants, and enhancing glutelin by polyploidization is an attractive strategy for improving the nutritional value of rice seeds and presents a great potential for enhancing the commercial value of rice. Elucidating the mechanisms underlying glutelin synthesis and accumulation in tetraploid rice is of great significance. Results: To enhance the nutritional value of rice, we developed tetraploid rice and evaluated the contents of various nutrient elements in mature seeds. The results revealed a significant increase in protein contents, including the total seed storage proteins, glutelins, and amino acids in tetraploid rice when compared with those in diploid rice. Tandem mass tag-based quantitative proteomic analyses of seeds revealed that glutelins regulated by several glutelin genes in 9311-4x were significantly up-regulated (≥1.5-fold), which was further verified by immunoblot analyses. In addition, temporal expression patterns of various glutelin subunits in different rice lines were investigated. The results revealed significant differences in the expression patterns between diploid and tetraploid rice seeds. Cytohistological analyses results revealed that the thickness of aleurone cell layers increased significantly by 32% in tetraploid rice, the structures of protein storage vacuoles (PSVs) in sub-aleurone cells were more diverse and abundant than those of diploid rice. Temporal expression and proteomic analyses results revealed that protein disulfide isomerase-like 1–1 expression levels were higher in tetraploid rice than in diploid rice, and that the gene responded to oxidative folding with increased levels of proglutelin and appropriate distribution of seed glutelins in tetraploid rice. Conclusion: The results of the present study revealed that polyploidization increased glutelin content by influencing glutelin biosynthesis, transport, and deposition, while variations in glutelin accumulation between tetraploid and diploid rice were largely manifested in the initial time, duration, and relative levels of various glutelin gene expressions during seed filling stages. These findings provide novel insights into improving the protein quality and nutritional value of rice seeds by polyploid breeding. [ABSTRACT FROM AUTHOR]

Background and objectives: Starch properties are closely related to the rice quality as starch interacts with other components during rice storage. However, several studies have neglected that the changes in proteins and lipids influence the properties of starch in rice. Herein, we used an artificial climate chest to characterize the effect of glutelin and lipid oxidation on the physicochemical properties of starch during rice storage. Findings: Oxidation occurs in glutelin and lipids during the rice storage stage (p <.01). The oxidation indexes of glutelin and lipids showed the same significant negative correlation in peak viscosity (PV), breakdown (BD), and setback (SB). In contrast, concerning amylose content, final viscosity (FV), and SB, the oxidation of glutelin rather than lipids was more closely related to the changes observed in starch properties (p <.01). Lipid oxidation significantly correlated with trough viscosity (TV) and amylopectin content than glutelin oxidation (p <.01). Conclusions: All the oxidation indicators of glutelin and lipids were inversely correlated with BD and SB (p <.01). Carbonyl compound content and fatty acid oxidation were significantly correlated with the physicochemical properties of rice starch. Significance and novelty: The physicochemical changes in starch are closely related to the oxidation of glutelin and lipids, which can be used as indicators for assessing rice quality. [ABSTRACT FROM AUTHOR]

Rice protein (RP) is a high-quality hypoallergenic plant protein, but its extremely poor water solubility makes it difficult to be applied in liquid food systems. Therefore, in-depth exploration of its gel properties is an effective way to broaden the application scenarios of RP. In this work, it was first found that the rate and strength of gel formation by RP at 25 °C strongly depended on the increase in alkali concentration (from 0.05 M to 0.125 M), i.e., alkali concentrations above 0.075 M were sufficient to induce the formation of a stable gel by 10% (w/v) of RP in 0.5 h. Increasing the temperature during alkali-induced RP gel formation (50 °C, 80 °C) greatly increased the rate of gel formation, whereas prolonged (>30 min) heat treatment resulted in liquefaction of the gel. A more in-depth analysis revealed that the alkali was able to depolymerize glutelin within the agglomerates in its native state, thereby forming a gel network among glutelin molecules at lower alkali concentrations (C NaOH = 0.075 M) mainly through hydrophobic interactions. Whereas, higher alkali concentration (C NaOH = 0.125 M) resulted in the rapid transformation of exposed free sulfhydryl groups into disulfide bonds, thus exerting a major contribution to the gel network, followed by hydrogen bonding. Furthermore, the phenomenon of heat-induced gel liquefaction was mainly attributed to the dissociation of glutelin subunits and was accompanied by an increase in the disordered structure of proteins in the amide III region. These findings may provide a scientific basis for the development of rice protein gel foods. [Display omitted] • The rate of RP gel formation was strongly dependent on the base concentration. • Continued heat treatment could lead to liquefaction of alkali-induced RP gels. • At C NaOH = 0.075 M, the intermolecular forces in gels were hydrophobic interactions. • At C NaOH = 0.125 M, disulfide and hydrogen bonds predominated in the RP gels network. • Liquefaction of RP gels was due to dissociation of glutelin subunits. [ABSTRACT FROM AUTHOR]

Abstract Background As the major storage protein in rice seeds, glutelins are synthesized at the endoplasmic reticulum (ER) as proglutelins and transported to protein storage vacuoles (PSVs) called PBIIs (Protein body IIs), where they are cleaved into mature forms by the vacuolar processing enzymes. However, the molecular mechanisms underlying glutelin trafficking are largely unknown. Results In this study, we report a rice mutant, named glutelin precursor accumulation6 (gpa6), which abnormally accumulates massive proglutelins. Cytological analyses revealed that in gpa6 endosperm cells, proglutelins were mis-sorted, leading to the presence of dense vesicles (DVs) and the formation paramural bodies (PMBs) at the apoplast, consequently, smaller PBII were observed. Mutated gene in gpa6 was found to encode a Na+/H+ antiporter, OsNHX5. OsNHX5 is expressed in all tissues analyzed, and its expression level is much higher than its closest paralog OsNHX6. The OsNHX5 protein colocalizes to the Golgi, the trans-Golgi network (TGN) and the pre-vacuolar compartment (PVC) in tobacco leaf epidermal cells. In vivo pH measurements indicated that the lumens of Golgi, TGN and PVC became more acidic in gpa6. Conclusions Our results demonstrated an important role of OsNHX5 in regulating endomembrane luminal pH, which is essential for seed storage protein trafficking in rice.

Proteins were extracted from a prickly pear seed cake using the Osborne extraction method. Physico-chemical, antioxidant and functional properties of the major protein fractions (albumin and glutelin) were studied. Glutelin fraction presented good amount of proteins (60.42% dry weight) with appreciable essential amino acids content (24.45% of total amino acids). The Fourier transform-infrared spectroscopy spectra showed between ~ 1200 and 1700 cm−1, characteristically peaks of proteins, namely, amide I, II and III for both fractions. Antioxidant activities of protein fractions were assessed in vitro through different antioxidant tests. The protein fractions exhibited good DPPH and metal scavenging activities. However, they demonstrated moderate reductive ability. Protein fractions had a minimum equilibrium surface tension at the isoelectric pH. They were characterized by interesting techno-functional properties such as emulsifying and foaming capacities which were affected by pH values. They also displayed significant water holding (480% for albumin fraction at pH 7) and oil holding (420% for glutelin at pH 7) capacities. The found results suggested that albumin and glutelin extracted from prickly pear seed cake could have important applications in food formulations. [ABSTRACT FROM AUTHOR]

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In this study, cumin protein isolates (CPI) and major protein fractions were extracted and separated from cumin seeds, their structure, physicochemical, and functional properties were investigated. Albumin (62.29%) and glutelin (25.16%) were the predominant protein fractions of cumin seeds. Glutamic acid (Glu) and aspartic acid (Asp) were the major amino acids of cumin proteins, whereas more hydrophobic and aromatic amino acids were predominantly found in chickpea protein isolates. Electrophoresis profiles indicated that CPI have more disulphide bonds than major protein fractions. The intrinsic fluorescence data revealed that glutelin displayed greater exposure of tyrosine (Tyr) and tryptophan (Trp) residues compared to albumin and CPI. Circular dichroism (CD) data showed CPI presented more α-helix (14.4%) and less β-strand (30.7%) than albumin and glutelin. The atomic force microscope (AFM) profile and hydrodynamic diameter (Dh) determination showed the presence of low particle size in albumin fractions. Differences in the hydrophobicity (Ho) and the zeta-potential (ζ) of CPI, albumin, and glutelin were also observed due to their difference in structure and amino acid composition. Compared with CPI and glutelin, albumin exhibited the highest emulsifying activity (103.67 m2/g) and stability (42.84 min) and the smallest emulsion particle size (4.29 μm). The CPI, albumin and glutelin presented typical U-shaped protein solubility–pH curves, with the lowest solubility at pH 4.0. Rheological investigation demonstrated that CPIs were efficient in forming a gel at 80.6°C, whereas glutelin could form the hardest gel at 92.6°C. The overall results suggested that the cumin proteins can be a promising protein source for the food industry.

Chinese quince seed proteins were sequentially extracted based on the modified Osborne method. Investigations showed that albumin and glutelin were the major fractions. The physicochemical and functional properties of these two fractions were determined. The results showed that both albumin and glutelin posed appropriate essential amino acid composition and met the minimum recommendation (World Health Organization/Food and Agriculture Organization) for adult diet, except for methionine. The hydrophobicity of albumin and glutelin were 1063.56 and 1170.21, respectively. According to differential scanning calorimeter analysis, the denaturation temperature of albumin and glutelin was 101.44 °C and 108.36 °C respectively, and the glutelin fraction had a better thermal stability. The solubility and apparent viscosity of albumin and glutelin were presented to be greatly influenced by pH values. The water holding capacity and oil adsorption capacity of glutelin were 5.44 g/g and 8.15 g/g, higher than those of albumin which were 3.76 g/g and 3.71 g/g, respectively. Circular dichroism determination revealed albumin and glutelin were mainly composed by α-helix and random coil structures. Albumin and glutelin presented the potential as favorable nutrition and functional additive in food industries. [ABSTRACT FROM AUTHOR]

Glutelin fraction from cocoa almond was hydrolyzed with alcalase for the production of hydrolysates. These were then fractionated by ultrafiltration to obtain peptides with a molecular weight (MW) lower than 3000 Da. The antioxidant activity (AOX) of the hydrolysates and peptides was assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH•), 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+), and oxygen radical absorbance capacity (ORAC) assays. Ultrafiltered peptide fraction with the highest AOX was purified by size exclusion chromatography, by which four main peaks were identified with a MW between 535 and 2959 Da. The peptide fraction P1 (MW = 2959 Da) showed the highest capacity to scavenge DPPH• and ABTS•+ radicals with radical scavenging activity DPPH• and ABTS•+ with EC50 values of 237.48 and 19.29 µg/mL, respectively, which were similar to those obtained with glutathione. These results show that enzymatic treatment of cocoa glutelin comprises an attractive bioprocess for the production of peptide fractions with AOX, which could be included in the design of functional foods; moreover, they show an alternative use of cocoa.

In this study, small molecular (≤3 kDa) Coix glutelin hydrolysate (CGH) was obtained by the method of enzymatic hydrolysis and then immunomodulatory activity was evaluated in vitro and in vivo. Stimulation index of mice splenocytes was increased in a dose-dependent manner after treated with 3.125–25 μg/mL CGH. Acid phosphatase in mice peritoneal macrophages was significantly improved after stimulated with CGH at some concentration. The CGH stimulated the secretion of NO from Raw264.7 in a concentration-dependent manner and also significantly inhibited lipopolysaccharide-induced cell excessive activation at some extent. After successive administration of CGH for 21 days, the spleen index of ICR was significantly increased to 3.73 mg/g for the group administrated 800 mg/kg CGH. Malondialdehyde (MDA) assay displayed that 200 mg/kg CGH increased mice serum MDA concentration, while the variation was obsolete in the other CGH groups. All results demonstrated that CGH took essential effects on immunomodulatory activities.

Vinegar soaked black soybean is a traditional Chinese food widely used for the treatment of hypertension. While its pharmacodynamic substance was not fully unveiled. It contained abundant glutelin, thus the purpose of this study was to obtain potent antihypertensive peptides from vinegar soaked black soybean. Black soybean was soaked with vinegar and then glutelin was first catalyzed by alcalase. Ultrafiltration, ion exchange chromatography and reversed-phase high performance liquid chromatography were sequentially applied to separate and purify the angiotensin-I converting enzyme (ACE) inhibitory peptides from glutelin hydrolysates. As a result, the fraction L1-4 with the highest ACE inhibitory activity (83.41%) at the final concentration of 0.01 mg/ml was obtained and five peptides were then identified. These peptides were further optimized by virtual screening combining with in silico proteolysis. Finally, a novel tetrapeptide Phe-Gly-Ser-Phe (FGSF) was obtained. FGSF exhibited high in vitro ACE inhibitory activity (IC50 = 117.11 μM) and in vivo hypotensive effect which maximally reduced systolic blood pressure of 21.95 mmHg at 20 mg/kg body weight in spontaneously hypertensive rats. Our study demonstrated that FGSF derived from vinegar soaked black soybean might be used as a promising ingredient for pharmaceuticals against hypertension and its related diseases. [ABSTRACT FROM AUTHOR]

Sedimentation is a major issue in juice production. This paper aims to study the mechanisms of precipitate formation during the storage of cloudy litchi juice. The sediment concentration, relative turbidity, and ζ potential were analyzed. The supernatant and sediment were separated to determine the contents of proteins and phenolics. The results showed that the amount of sediment increased during the storage. In addition, the total protein and total phenolic content in the supernatant decreased, whereas the glutelin and total phenolic contents in the sediment increased significantly (p < 0.05). Moreover, our results showed that the amounts of procyanidin B2 and quercetin-3-O-rutinose-7-O-rhamnoside in the supernatant decreased noticeably. However, these two substances could not be detected in the sediment. In summary, the formation of sediment from litchi juice is mainly caused by the slow denaturation of proteins and the oxidation of procyanidin B2 and quercetin-3-O-rutinose-7-O-rhamnoside. [ABSTRACT FROM AUTHOR]

Key message: GluA and GluB-4/5 glutelin subfamilies are mainly localized to outer region of the endosperm, particularly in its ventral side, in rice grain, but GluC is localized to throughout the endosperm. The major seed storage protein in rice (Oryza sativa) is glutelin, which forms a vacuole-derived protein body type-II. Glutelins are encoded by multiple genes, and generally comprise four protein subfamilies, namely, GluA, GluB, GluC, and GluD: however, the localization pattern of glutelin in rice grains remains obscure. In this study, we investigated the localization pattern of five subtypes of the glutelin protein in rice grains using glutelin-subtype specific antibodies. Immunoblot analysis against sequentially polished rice flour fractions from three crop years and seven japonica rice varieties revealed that GluA was strongly localized in the outer region of the endosperm, including the subaleurone layer, whereas GluC was distributed throughout the endosperm. Among the glutelin subtypes, GluA was mostly found in the outer region of the rice grain, followed by GluB-4/5, GluB-1, GluD, and GluC. Immunofluorescence labeling microscopy analysis using immature rice seeds clearly revealed that the localization pattern of GluC and GluD was completely different from that of GluA and GluB. Expression levels of all glutelins, particularly GluA, GluB-1, and GluB-4/5, were stronger on the ventral than dorsal side in rice grains. These results provide strong and consistent evidence that glutelins localize to the rice grain in a subfamily-dependent manner. [ABSTRACT FROM AUTHOR]

Protein content is one of the main nutrition quality traits used to measure nutrition value in rice (Oryza sativa L.) Therefore, improving the protein content is a main target for nutrition quality breeding in rice. Previous studies have mainly focused on the total protein content in brown and polished rice using bi-parental segregating populations. Few researchers have focused on four different protein component traits (glutelin, prolamin, albumin, and globulin) in rice, and little is known regarding association analysis in natural populations. In this study, 329 japonica accessions (Oryza sativa L. subsp. japonica Kato) were collected from worldwide geographic distributions and genotyped using 154 microsatellite markers to detect the association between four protein component traits and relative markers in the tested panel. The Coomassie Brilliant Blue G-250 method was used to measure the phenotype of four protein components. A total of 845 amplified alleles were detected with allele number ranging from 2 to 9. The whole population was divided into three subgroups via software STRUCTURE 2.3.4. The scatterplot showed that the LD (linkage disequilibrium) decay distance was about 30 cM in the whole tested population. A total of 15 simple sequence repeats (SSR) markers were identified by using both the general linear model (GLM) and mixed linear model (MLM). These associated marker loci can provide a higher variety of choices in improving the nutrition quality of rice. In addition, the carrier materials with excellent alleles identified in this study can be used as parental genotypes in rice molecular breeding in the future. [ABSTRACT FROM AUTHOR]

Multigenic glutelins and monogenic globulin are major storage proteins accumulating in vacuole-derived protein body (PB-II) of rice (Oryza sativa L.) seeds. Because their interplay in PB-II formation was scarcely known, the effect of globulin-less mutation on glutelin accumulation was investigated. In globulin-less mutants, no phenotypic defect was found in seed and plant growth, while PB-II was deformed and apparent glutelin composition was changed, producing new glutelin α polypeptides X1–X5. 2D-PAGE of different combinations of globulin-less and glutelin subunit mutations suggested that the X1/X2, X3, and X4/X5 were derived from glutelin GluB1/GluB2/GluB4, GluA3, and GluA1/GluA2 subunits, respectively. Western blot with glutelin GluB4 subunit-specific and its variable region discriminable antibodies indicated at least in part the new spots X1/X2 are partially degraded products of GluB4 α polypeptides by the removal of 2–39 residues from C-terminus. Time course experiments with maturing seeds indicated the partial degradation of GluB4 occurred earlier (from 7 days after flowering) and higher than that of GluA1/GluA2. Considering the above results together with the fact that globulin accumulates at the periphery of PB-II and its absence produces deformed PB-II, globulin protects glutelins from proteinase digestion and thereby facilitates stable glutelin accumulation.

Proteins are among the most important molecules on Earth. Their structure and aggregation behavior are key to their functionality in living organisms and in protein-rich products. Innovations, such as increased computer size and power, together with novel simulation tools have improved our understanding of protein structure-function relationships. This review focuses on various proteins present in plants and modeling tools that can be applied to better understand protein structures and their relationship to functionality, with particular emphasis on plant storage proteins. Modeling of plant proteins is increasing, but less than 9% of deposits in the Research Collaboratory for Structural Bioinformatics Protein Data Bank come from plant proteins. Although, similar tools are applied as in other proteins, modeling of plant proteins is lagging behind and innovative methods are rarely used. Molecular dynamics and molecular docking are commonly used to evaluate differences in forms or mutants, and the impact on functionality. Modeling tools have also been used to describe the photosynthetic machinery and its electron transfer reactions. Storage proteins, especially in large and intrinsically disordered prolamins and glutelins, have been significantly less well-described using modeling. These proteins aggregate during processing and form large polymers that correlate with functionality. The resulting structure-function relationships are important for processed storage proteins, so modeling and simulation studies, using up-to-date models, algorithms, and computer tools are essential for obtaining a better understanding of these relationships.

The effects of ultrasonic-assisted extraction (UAE, 200 W, 20 min) on the yield and physicochemical properties of different walnut proteins (WNPs, including albumin, globulin, and glutelin) were investigated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that UAE could result in protein molecular fragmentation of albumin, but did not affect the major bands of globulin and glutelin. The CD spectra demonstrated that different WNPs obtained by UAE had different changes in their secondary structure. Under UAE, there was an increase in surface hydrophobicity (H0) of albumin and gluten and no change in the fluorescence intensity, while decreases were observed in the H0 and fluorescence intensity of globulin; and the contents of total and surface free sulfhydryl in albumin dramatically decreased. UAE reduced the size of the particles and the dimension of the microstructures in albumin and gluten, indicating that ultrasound could unfold protein aggregates. In addition, UAE increased the solubility, emulsifying activity (EA), foaming capacity (FC), and foam stability (FS) of the obtained proteins. The above results indicate that ultrasound extraction is a promising approach to improve the extraction yield and properties of walnut proteins.