Search

Summary: Projected global climate change is a potential threat for food security. Both rising atmospheric CO2 concentrations ([CO2]) and temperatures have significant impacts on crop productivity, but the combined effects on grain quality are not well understood.We conducted an open‐air field experiment to determine the impacts of elevated [CO2] (E‐[CO2], up to 500 μmol mol−1) and warming (+2°C) on grain yield, protein and amino acid (AAs, acid digests) in a rice–winter wheat rotation system for 2 yr.E‐[CO2] increased grain yield by 11.3% for wheat and 5.9% for rice, but decreased grain protein concentration by 14.9% for wheat and by 7.0% for rice, although E‐[CO2] slightly increased the ratio of essential to nonessential AAs. With a consistent decline in grain yield, warming decreased protein yield, notably in wheat, despite a smaller increase in protein concentration.These results indicate that warming could partially negate the negative impact by E‐[CO2] on grain protein concentration at the expense of grain yield; this tradeoff could not fully offset the negative effects of climate change on crop production. [ABSTRACT FROM AUTHOR]

Aseptic‐packaged cooked rice (APCR) is a rice‐based food product with a rapidly increasing market size, and APCR made of fragrant rice (FR) has recently appeared on the market. The fragrance of FR is produced by a combination of odoriferous compounds, among which 2‐acetyl‐1‐pyrroline (2AP) has been identified as the most important contributor to overall aroma. This study describes the development of a method to quantify 2AP in FR‐based APCR using headspace solid‐phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC‐MS). The recovery of 2AP spiked into APCR was lower than 10%, which suggests significant matrix effects and inappropriateness of external standard‐based calibration. For standard addition calibration method, up to 1,000 ng of 2AP were spiked into APCR containing 0% to 100% FR. Subsequent regression analyses of recovered peak area (Y) as a function of the amount of 2AP spiked (X) yielded highly linear calibration curves (R2 > 0.9917) with consistent slopes (RSD = 2.7%), regardless of FR composition. Y‐intercepts, however, which represent the amount of 2AP in APCR without spiking, increased linearly (R2 = 0.9898) in proportion to the composition of FR in the APCR. The amount of 2AP in APCR, determined by extrapolating the standard addition calibration curves, also increased linearly (R2 = 0.9963) as a function of FR composition. Practicality of developed method was tested by monitoring 2AP contents in APCR under realistic storage conditions, which successfully demonstrated 38% and 60% 2AP reductions in APCR of 20% FR after 1 and 2 months of storage at 25°C, respectively. The present study demonstrates that a standard addition method, whereby up to 1,000 ng of 2AP standard is spiked into 4 g of APCR containing 5%–100% FR in a 20‐mL headspace vial followed by SPME/GC‐MS, may serve as an effective means of quantitating 2AP in fragrant rice‐based APCR. Using standard addition calibration method, up to 1,000 ng of 2‐acetyl‐1‐pyrroline (2AP) was spiked into aseptic‐packaged cooked rice (APCR) containing 0% to 100% fragrant rice (FR). Subsequent regression equations relating recovered 2AP (Y) against spiked amount (X) showed strong linearity and consistent slopes regardless of FR composition, but linearly increasing Y‐intercepts in proportion to FR composition in APCR. The amount of 2AP in APCR calculated by extrapolation of calibration curves increased in proportion to the composition of FR in APCR. Developed method could successfully elucidate 2AP content changes in APCR made of fragrant rice during market circulation, which proved its practicality. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to determine whether texture perception and acceptance of cooked rice could differ with cultural background, especially between Korean and American participants. Participants evaluated eight cooked rice samples with respect to intensities of textural attributes such as visual stickiness, hardness, stickiness and chewiness. Participants also rated the acceptability of and familiarity with those samples. Results showed that Americans gave higher ratings to cooked rice samples with respect to visual stickiness, stickiness and chewiness, while Koreans gave higher ratings to hardness than their counterpart. For Americans, chewiness was considered as a negative driver; whereas for Koreans, visual stickiness and stickiness were identified as positive drivers of overall liking for cooked rice samples. Moreover, a familiarity level of cooked rice samples was a pronounced positive driver of liking for both American and Korean participants. In conclusion, our findings provide empirical evidence that cultural background influences texture perception and liking of cooked rice. [ABSTRACT FROM AUTHOR]

Summary: Whilst WRKY transcription factors are known to be involved in diverse plant responses to biotic stresses, their involvement in abiotic stress tolerance is poorly understood. OsFRDL4, encoding a citrate transporter, has been reported to be regulated by ALUMINUM (Al) RESISTANCE TRANSCRIPTION FACTOR 1 (ART1) in rice, but whether it is also regulated by other transcription factors is unknown. We define the role of OsWRKY22 in response to Al stress in rice by using mutation and transgenic complementation assays, and characterize the regulation of OsFRDL4 by OsWRKY22 via yeas one‐hybrid, electrophoretic mobility shift assay and ChIP‐quantitative PCR. We demonstrate that loss of OsWRKY22 function conferred by the oswrky22 T‐DNA insertion allele causes enhanced sensitivity to Al stress, and a reduction in Al‐induced citrate secretion. We next show that OsWRKY22 is localized in the nucleus, functions as a transcriptional activator and is able to bind to the promoter of OsFRDL4 via W‐box elements. Finally, we find that both OsFRDL4 expression and Al‐induced citrate secretion are significantly lower in art1 oswrky22 double mutants than in the respective single mutants. We conclude that OsWRKY22 promotes Al‐induced increases in OsFRDL4 expression, thus enhancing Al‐induced citrate secretion and Al tolerance in rice. [ABSTRACT FROM AUTHOR]

Summary: In rice, amylose content (AC) is controlled by a single dominant Waxy gene. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR‐associated 9 (Cas9) to introduce a loss‐of‐function mutation into the Waxy gene in two widely cultivated elite japonica varieties. Our results show that mutations in the Waxy gene reduce AC and convert the rice into glutinous ones without affecting other desirable agronomic traits, offering an effective and easy strategy to improve glutinosity in elite varieties. Importantly, we successfully removed the transgenes from the progeny. Our study provides an example of generating improved crops with potential for commercialization, by editing a gene of interest directly in elite crop varieties. [ABSTRACT FROM AUTHOR]

Summary: High temperature significantly alters the amylose content of rice, resulting in mature grains with poor eating quality. However, only few genes and/or quantitative trait loci involved in this process have been isolated and the molecular mechanisms of this effect remain unclear. Here, we describe a floral organ identity gene, OsMADS7, involved in stabilizing rice amylose content at high temperature. OsMADS7 is greatly induced by high temperature at the early filling stage. Constitutive suppression of OsMADS7 stabilizes amylose content under high temperature stress but results in low spikelet fertility. However, rice plants with both stable amylose content at high temperature and normal spikelet fertility can be obtained by specifically suppressing OsMADS7 in endosperm. GBSSI is the major enzyme responsible for amylose biosynthesis. A low filling rate and high expression of GBSSI were detected in OsMADS7 RNAi plants at high temperature, which may be correlated with stabilized amylose content in these transgenic seeds under high temperature. Thus, specific suppression of OsMADS7 in endosperm could improve the stability of rice amylose content at high temperature, and such transgenic materials may be a valuable genetic resource for breeding rice with elite thermal resilience. [ABSTRACT FROM AUTHOR]

Three types of modified Indica rice starch were obtained by combining mechanical activation (MA) with octenyl succinic anhydride (OSA) esterification. The samples were mechanically activated Indica rice starch (MA-IRS), mechanically activated Indica rice starch esterified by OSA (OSA-MA-IRS) and Indica rice starch that was esterified by OSA and mechanically activated (MAOSA-IRS). The physicochemical properties of the three types of modified Indica rice starch were studied. The results indicate that the particle shape of OSA-MA-IRS was the most irregular among the three types of modified Indica rice starch, and the changes in morphology of MAOSA-IRS were similar to those in mechanically activated Indica rice starch (MA-IRS), but the granules of MS-OSA-IRS were smaller than the granules of MA-IRS after an identical mechanical activation time. The results of X-ray diffraction showed that a new crystalline structure formed during preparation of OSA-MA-IRS, and the crystal structure of OSA-IRS was more easily destroyed by mechanical force than that of IRS. Therefore, for the same mechanical activation time, the transparency and reducing power for each sample were ranked in the following order: MA-OSA-IRS, MA-IRS, and OSA-MA-IRS. However, the blue value from iodine staining and apparent viscosity showed the reverse trend. The emulsifying activity index decreased in the following order: OSA-MA-IRS, MA-OSA-IRS, and MA-IRS. [ABSTRACT FROM AUTHOR]

Soils deficient in P are widespread in major rice (Oryza sativa L.) ecosystems. In view of declining reserves of rock phosphate and the rising costs of P fertilizers, breeding rice varieties tolerant to low P has become important for future food security. Four different methods (hydroponics without sand [H], hydroponics with sand [HS], large pots with soil [PS], and glasses with soil [GS]) were evaluated using rice aus variety Nagina 22 (N22) and its known gain-of-function (gof) and loss-of-function (lof) mutants to screen for low P tolerance in the field. In -P (no addition of NaH2PO4) shoots, dry weight was significantly higher in gof mutant NH787 than in N22 in HS, PS, and GS but not in H, with fold increases of 1.8 in HS, 5.2 in GS, and 9.4 in PS. In HS, in -P, out of six traits only shoot dry weight was significantly higher in gof and lower in lof mutants. However, in GS both root and shoot dry weight could confirm gof and lof mutants. It took 40 d in GS and 70 d in PS to differentiate between growth in -P/low P and +P (0.32 mM NaH2PO4) and between gof and lof mutants. Thus, shoot dry weight at 30 d in HS and root and shoot dry weight at 40 d in GS are best to differentiate between genotypes grown in -P/low P and +P soil and also between gof and lof mutants for low P tolerance. The HS method can be performed in ambient conditions and needs 70% less medium compared with H. If germplasm is to be screened for low P tolerance on a large scale and if there is no access to low-P soil, then screening using HS is the best approach. [ABSTRACT FROM AUTHOR]

The consumption of resistant starch (RS), which can increase satiety and reduce calorie intake, may help ameliorate lifestyle-related diseases such as diabetes, hypertension, and obesity. The identification of genes or quantitative trait loci (QTLs) may facilitate improvement in the amounts and properties of RS in cereals such as rice. A genome-wide association mapping of the RS content in milled rice grain was carried out to identify QTLs in a rice germplasm collection. The RS contents among 105 rice accessions ranged from 0.3 to 2.42%, and the apparent amylose content (AAC) was positively correlated with the RS content (R²=0.75). Four QTLs were detected, and each explained a total phenotypic variation of 10-13%. Two of these, on chromosome 6, were identified at theWaxy gene locus encoding granule-bound starch synthase I and starch synthase IIa. The other two QTLs, on chromosomes 8 and 9, were close to candidate genes encoding the starch debranching enzyme isoamylase I and ADP-glucose pyrophosphorylase small subunit 1, respectively. The results of this study should improve our understanding of the genetic basis of RS in milled rice and may assist plant breeders attempting to develop new rice varieties and food processors working to develop functional foods. [ABSTRACT FROM AUTHOR]

Rice ( Oryza sativa L.) is one of the most important food crops in the world. In red rice, black, purple, brown, and brown red rice, major bioactive components are gallic, protocatechuic, hydroxybenzoic, p-coumaric,ferulic, sinapic acid, cyanidin-3-O-glucoside, peonidin-3-O-glucoside,flavan-3-ol (+) catechin and (−) epicatechin,flavanols (flavan- 3-ols), isoflavones, γ-oryzanol contents, compositions of steryl, triterpene alcohol ferulates proportions, and tocopherols, etc. This review provides information of pigmented rice in the form of bioactive compounds, concentration, activities and its health's benefit. These bioactive compounds are having immense potential for many health benefit effects and can act as antitumour, anti-atherosclerosis, anti-diabetic, anti-allergicagents, alleviating gallstones, anticancer activity, anti-inflammatoryeffects, and others. [ABSTRACT FROM AUTHOR]

The physicochemical characteristics, texture profiles and consumer acceptance of rice pan bread with various levels of water roux starter ( Tangzhong) were investigated. Water roux starter (1.5-6.0%, flour base) was added to the bread dough. The bread samples containing water roux starter had significantly higher moisture contents and specific volumes ( P < 0.05). Water roux starter results in the bread having lower hardness, gumminess and chewiness, but there was no significant difference in cohesiveness and springiness. The results of the consumer acceptance test showed that the subjects were split into two groups; one consumer group (52.3%) preferred the bread with 4.5% and 6.0% (flour base) of water roux starter, and the other group (47.7%) preferred the control sample. Adding water roux starter decreased hardness of the bread so that it met the more than 50% of consumers who preferred soft texture. The textural change by adding water roux starter showed positive consumer acceptance in the rice pan bread. Practical Applications Texture of pan bread is one of key factor for bread quality. Additional ingredients such as glyceryl monostearate, various gums and/or methyl cellulose to make pan bread soft and glutinous are not necessary when water roux starter was applied in rice pan bread. Water roux starter can be applied to other bread making for baking soft and glutinous bread without any additional additives. In addition, water roux starter in the bread was effective in making same volume of bread with few amounts of ingredient, which is beneficial to bakery industry. [ABSTRACT FROM AUTHOR]

The cellular levels of methylglyoxal (MG), a toxic byproduct of glycolysis, rise under various abiotic stresses in plants. Detoxification of MG is primarily through the glyoxalase pathway. The first enzyme of the pathway, glyoxalase I (GLYI), is a cytosolic metalloenzyme requiring either Ni2+ or Zn2+ for its activity. Plants possess multiple GLYI genes, of which only some have been partially characterized; hence, the precise molecular mechanism, subcellular localization and physiological relevance of these diverse isoforms remain enigmatic. Here, we report the biochemical properties and physiological role of a putative chloroplast-localized GLYI enzyme, OsGLYI-8, from rice, which is strikingly different from all hitherto studied GLYI enzymes in terms of its intracellular localization, metal dependency and kinetics. In contrast to its predicted localization, OsGLYI-8 was found to localize in the nucleus along with its substrate, MG. Further, OsGLYI-8 does not show a strict requirement for metal ions for its activity, is functional as a dimer and exhibits unusual biphasic steady-state kinetics with a low-affinity and a high-affinity substrate-binding component. Loss of AtGLYI-2, the closest Arabidopsis ortholog of OsGLYI-8, results in severe germination defects in the presence of MG and growth retardation under salinity stress conditions. These defects were rescued upon complementation with AtGLYI-2 or OsGLYI-8. Our findings thus provide evidence for the presence of a GLYI enzyme and MG detoxification in the nucleus. [ABSTRACT FROM AUTHOR]

The drought-induced 19 protein family consists of several atypical Cys2/His2-type zinc finger proteins in plants and plays an important role in abiotic stress. In this study, we found that overexpressing OsDi19-4 in rice altered the expression of a series of abscisic acid (ABA)-responsive genes, resulting in strong ABA-hypersensitive phenotypes including ABA-induced seed germination inhibition, early seedling growth inhibition and stomatal closure. On the contrary, OsDi19-4 knockdown lines were less sensitive to ABA. Additionally, OsCDPK14 was identified to interact with OsDi19-4 and be responsible for the phosphorylation of OsDi19-4, and the phosphorylation of OsDi19-4 was further enhanced after the treatment of ABA. Apart from these, OsDi19-4 was shown to directly bind to the promoters of OsASPG1 and OsNAC18 genes, two ABA-responsive genes, and regulate their expression. Transient expression assays confirmed the direct regulation role of OsDi19-4, and the regulation was further enhanced by the increased phosphorylation of OsDi19-4 after the treatment of ABA. Taken together, these data demonstrate that OsDi19-4 acts downstream of OsCDPK14 to positively regulate ABA response by modulating the expression of ABA-responsive genes in rice. [ABSTRACT FROM AUTHOR]

Under phosphate (Pi) starvation, plants increase the secretion of purple acid phosphatases (PAPs) into the rhizosphere to scavenge organic phosphorus (P) for plant use. To date, only a few members of the PAP family have been characterized in crops. In this study, we identified a novel secreted PAP in rice, OsPAP10c, and investigated its role in the utilization of external organic P. OsPAP10c belongs to a monocotyledon-specific subclass of Ia group PAPs and is specifically expressed in the epidermis/exodermis cell layers of roots. Both the transcript and protein levels of OsPAP10c are strongly induced by Pi starvation. OsPAP10c overexpression increased acid phosphatase (APase) activity by more than 10-fold in the culture media and almost fivefold in both roots and leaves under Pi-sufficient and Pi-deficient conditions. This increase in APase activity further improved the plant utilization efficiency of external organic P. Moreover, several APase isoforms corresponding to OsPAP10c were identified using in-gel activity assays. Under field conditions with three different Pi supply levels, OsPAP10c-overexpressing plants had significantly higher tiller numbers and shorter plant heights. This study indicates that OsPAP10c encodes a novel secreted APase that plays an important role in the utilization of external organic P in rice. [ABSTRACT FROM AUTHOR]

A preparation method of arsenic-containing white rice grains as calibration standards was developed for the X-ray fluorescence (XRF) analysis of arsenic in rice grains. Calibration standards were prepared by adding 10g of white rice grains (from Japan) to 100ml methanol-containing dimethylarsinic acid corresponding to 2-100 μg arsenic. The mixture was heated, dried at 150°C, cooled to room temperature, and then stored in a silica gel desiccator. A total of 5.0 g of each calibration standard was packed into a polyethylene cup (32mminternal diameter and 23mmheight) coveredwith a 6-μm-thick polypropylene film and then analyzed by wavelength-dispersive XRF spectrometry. The calibration curve for arsenic obtained from the white rice grains containing arsenic showed good linearity over a concentration range of 0.21-5.00mg kg-1 arsenic. The limit of detection of arsenic was 0.080mgkg-1. To check the reliability of the XRF method, the concentrations of arsenic in six samples of grain cereals and two samples of flour were compared with those obtained by atomic absorption spectrometry after acid decomposition. The values obtained by both analytical methods showed good agreement. [ABSTRACT FROM AUTHOR]

BACKGROUND Chalkiness has a deleterious influence on rice appearance and milling quality. We identified a notched-belly mutant with a high percentage of white-belly, and thereby developed a novel comparison system that can minimize the influence of genetic background and growing conditions. Using this mutant, we examined the differences in chemical composition between chalky and translucent endosperm, with the aim of exploring relations between occurrence of chalkiness and accumulation of starch, protein and minerals. RESULTS Comparisons showed a significant effect of chalkiness on chemical components in the endosperm. In general, occurrence of chalkiness resulted in higher total starch concentration and lower concentrations of the majority of the amino acids measured. Chalkiness also had a positive effect on the concentrations of As, Ba, Cd, Cr, Mn, Na, Sr and V, but was negatively correlated with those of B, Ca, Cu, Fe and Ni. By contrast, no significant chalkiness effect on P, phytic acid-P, K, Mg or Zn was observed. In addition, substantial influence of the embryo on endosperm composition was detected, with the embryo showing a negative effect on total protein, amino acids such as Arg, His, Leu, Lys, Phe and Tyr, and all the 17 minerals measured, excluding Ca, Cu, P and Sr. CONCLUSION An inverse relation between starch and protein as well as amino acids was found with respect to chalkiness occurrence. Phytic acid and its colocalized elements K and Mg were not affected by chalkiness. The embryo exerted a marked influence on chemical components of the endosperm, in particular minerals, suggesting the necessity of examining the role of the embryo in chalkiness formation. © 2016 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Little has been reported about the sensory impact of degree of milling ( DOM) on raw, uncooked rice. This study focuses on the effects of DOM, which was measured by surface lipid content ( SLC), on appearance and aroma attributes of raw rice, as well as the appearance of cooked rice; greater DOM leads to lesser SLC levels. RESULTS Milled-rice samples with SLCs of 0.64, 0.59, 0.42 and 0.25%, as well as brown rice (2.27% total lipid content), were evaluated by trained panelists on three appearance- and five aroma-related attributes of raw rice, as well as four appearance-related attributes of the resultant cooked rice. All milled-rice samples, varying in SLC level from 0.64% to 0.25%, differed from brown rice with respect to raw-rice and cooked-rice appearance and aroma attributes. A significant sensory difference among the four raw-rice samples was present only in the degree of whiteness; however, such a difference was absent once the samples were cooked. When cooked, highly milled rice (0.25% SLC) was rated glossier than either lightly milled rice (0.64% SLC) or brown rice. CONCLUSION The present study demonstrated that sensory impacts of DOM on raw rice were present between brown rice and milled-rice samples, but not among the milled-rice samples varying in SLC level from 0.64% to 0.25%. The overall findings indicate that consumers may not detect appearance- or aroma-related differences among raw-rice samples ranging in SLC from 0.64% to 0.25%. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Although rice ( Oryza sativa L.) is the third largest food crop, relatively fewer studies have been reported on rice geographical origin based on light element isotope ratios in comparison with other foods such as wine, beef, juice, oil and milk. Therefore this study tries to discriminate the geographical origin of the same rice cultivars grown in different Asian countries using the analysis of C, N, O and S stable isotope ratios and chemometrics. RESULTS The δ 15NAIR, δ 18OVSMOW and δ 34SVCDT values of brown rice were more markedly influenced by geographical origin than was the δ 13CVPDB value. In particular, the combination of δ 18OVSMOW and δ 34SVCDT more efficiently discriminated rice geographical origin than did the remaining combinations. Principal component analysis ( PCA) revealed a clear discrimination between different rice geographical origins but not between rice genotypes. In particular, the first components of PCA discriminated rice cultivated in the Philippines from rice cultivated in China and Korea. CONCLUSION The present findings suggest that analysis of the light element isotope composition combined with chemometrics can be potentially applicable to discriminate rice geographical origin and also may provide a valuable insight into the control of improper or fraudulent labeling regarding the geographical origin of rice worldwide. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Monsanto's Beachell-Borlaug International Scholars Program (MBBISP) is named after the greatest wheat (Triticum aestivum L.) and rice (Oryza sativa L.) breeders of the 20th century. Monsanto, through the MBBISP, invested $13 million over an 8-year period for training rice and wheat breeders from around the world. The judging panel for MBBISP selected 89 scholars from 432 applicants. The selected scholars were from 30 different countries. Scholars selected included 35 women and 54 men, 37 in rice breeding and 52 in wheat breeding. Currently 23 scholars are still completing their Ph.D. programs (as of 2018). This past year, Monsanto established the "Ted Crosbie MBBISP Impact Award" to begin recognizing notable contributions by a scholar, not only in wheat and rice breeding, but also in other crops. Scholar impact is just beginning to be recognized since the earliest graduates have been employed for less than 6 years. To be eligible for this award, scholars must have received their Ph.D. Bhoja Basnet, who is in charge of International Maize and Wheat Improvement Center's (CIMMYT's) hybrid wheat breeding program, was selected to receive the Ted Crosbie MBBISP Impact Award for 2017. Employment of scholars post Ph.D. is reviewed. [ABSTRACT FROM AUTHOR]

Bsister MADS-box genes play key roles in female reproductive organ and seed development throughout seed plants. This view is supported by their high conservation in terms of sequence, expression and function. In grasses, there are three subclades of Bsister genes: the OsMADS29-, the OsMADS30- and the OsMADS31-like genes. Here, we report on the evolution of the OsMADS30-like genes. Our analyses indicate that these genes evolved under relaxed purifying selection and are rather weakly expressed. OsMADS30, the representative of the OsMADS30-like genes from rice (Oryza sativa), shows strong sequence deviations in its 30 region when compared to orthologues from other grass species. We show that this is due to a 2.4-kbp insertion, possibly of a hitherto unknown helitron, which confers a heterologous C-terminal domain to OsMADS30. This putative helitron is not present in the OsMADS30 orthologues from closely related wild rice species, pointing to a relatively recent insertion event. Unlike other Bsister mutants O. sativa plants carrying a T-DNA insertion in the OsMADS30 gene do not show aberrant seed phenotypes, indicating that OsMADS30 likely does not have a canonical 'Bsister function'. However, imaging-based phenotyping of the TDNA carrying plants revealed alterations in shoot size and architecture. We hypothesize that sequence deviations that accumulated during a period of relaxed selection in the gene lineage that led to OsMADS30 and the alteration of the C-terminal domain might have been a precondition for a potential neo-functionalization of OsMADS30 in O. sativa. [ABSTRACT FROM AUTHOR]

Chlorophylls absorb and transfer light energy to the photosynthetic system. Consequently, chlorophyll content is strongly related to crop biomass and yield. We isolated a rice spontaneous mutant, lower chlorophyll b 1 (lcb1), from a recombinant inbred line population. Under normal growth conditions, lcb1 plants produced yellow leaves with decreased total chlorophyll and chlorophyll b contents, but normal chlorophyll a content. Photosynthetic and fluorescence parameters differed between wild-type and lcb1 plants. Compared with wild type, lcb1 had a higher electron transfer rate, a lower photochemical quenching coefficient and significantly reduced grain number, biomass and yield. A recessive nuclear gene controlled the mutant trait. Through map-based cloning, we located the LCB1 gene in a 117.4-kb region on the short arm of chromosome 3, close to the centromere, in a region containing 15 predicted candidate genes. None of these genes was directly related to chlorophylls or the chloroplast; therefore, lcb1 may be a mutation of a novel gene. These results will be useful for further research on the molecular mechanisms controlling biogenesis and chloroplast biochemical processes. [ABSTRACT FROM AUTHOR]

A sensitive and robust high-performance liquid chromatography coupled with electrospray tandem mass spectrometry method for the identification and quantification of glutathione and phytochelatins from rice was developed. Homogenized samples were extracted with water containing 100 mM dithiothreitol, and solid-phase extraction using polymer anion exchange resin was employed for sample purification. Chromatography was performed on a polymeric column with acetonitrile and water containing 0.1% formic acid as the mobile phase at the flow rate of 300 μL/min. The limit of quantitation was 6-100 nM. This assay showed excellent linearity for both glutathione and phytochelatins over physiological normal ranges, with correlation coefficients (r) > 0.9976. Recoveries for four biothiols were within the range of 76-118%, within relative standard deviations less than 15%. The intraday precision (n = 7) was 2.1-13.3%, and the interday precision over 15 days was 4.3-15.2%. The optimized method was applied to analyze tissue samples from rice grown using nutrient solutions with three different cadmium concentrations (0, 50, and 100 M).With increasing cadmium concentrations, the content of phytochelatin 2 and phytochelatin 3 in rice roots increased, in contrast to most phytochelatins, and the content of glutathione in rice stems and roots decreased significantly. [ABSTRACT FROM AUTHOR]

The intracellular potassium ( K+) homeostasis, which is crucial for plant survival in saline environments, is modulated by K+ channels and transporters. Some members of the high-affinity K+ transporter ( HAK) family are believed to function in the regulation of plant salt tolerance, but the physiological mechanisms remain unclear. Here, we report a significant inducement of O s HAK 21 expression by high-salinity treatment and provide genetic evidence of the involvement of Os HAK21 in rice salt tolerance. Disruption of O s HAK 21 rendered plants sensitive to salt stress. Compared with the wild type, oshak21 accumulated less K+ and considerably more Na+ in both shoots and roots, and had a significantly lower K+ net uptake rate but higher Na+ uptake rate. Our analyses of subcellular localizations and expression patterns showed that Os HAK21 was localized in the plasma membrane and expressed in xylem parenchyma and individual endodermal cells (putative passage cells). Further functional characterizations of Os HAK21 in K+ uptake-deficient yeast and A rabidopsis revealed that Os HAK21 possesses K+ transporter activity. These results demonstrate that Os HAK21 may mediate K+ absorption by the plasma membrane and play crucial roles in the maintenance of the Na+/ K+ homeostasis in rice under salt stress. [ABSTRACT FROM AUTHOR]

Photosynthesis in C3 plants is significantly limited by mesophyll conductance ( gm), which can vary with leaf anatomical traits and nitrogen ( N) supplements. Several studies have investigated the response of gm to N supplements; however, none examined the implications of N supplements on the response of gm to rapid environmental changes. Here we investigated the effect of N supplement on gm and the response of gm to change of CO2, temperature and irradiance in rice. High N supplement ( HN) increased mesophyll cell wall surface area and chloroplast surface area exposed to intercellular airspace per leaf area, and reduced cell wall thickness. These changes resulted in increased gm. The gm of leaves with HN was more sensitive to changes in CO2 concentration, temperature and irradiance. The difference in leaf structural features between low N supplement and HN indicates that a rapid change in gm is related to the regulation of diffusion through biological membranes rather than leaf structural features. These results will contribute to an understanding of the determinants of gm response to rapid changes in environmental factors. [ABSTRACT FROM AUTHOR]

Rice bran oil contains beneficial compounds that contribute to its resistance to oxidation, as well as the health of consumers. However, concerns have surfaced in recent years related to the heavy metal content of rice and rice-derived products. Rice is known to take up arsenic at a higher rate than other grain crops. The United Nations Food and Agriculture Organization recently set an acceptable limit of 0.2 μg/g of arsenic in rice, but no limits have been set for other edible products such as rice bran oil. Furthermore, arsenic levels in rice bran oil have not been thoroughly investigated. In this work we characterized both crude and refined rice bran oils, including detailed chemical composition, analysis of bioactive lipids, and a multi-faceted approach for assessing prior oxidative history and stability of rice bran oils. We also analyzed levels of arsenic, lead, mercury, cadmium, and zinc. Metal concentrations were verified through two independent analytical laboratories. Concentrations of lead and cadmium in rice bran oils were generally low. Zinc concentrations were detectable but low relative to daily dietary allowances. Arsenic and mercury concentrations differed between the methods used to collect the data. We explore in this work the origins of these differences. Practical applications: Rice absorbs arsenic at a high rate relative to other crops, which has lead to increased consumer concern regarding toxic metal contaminants in rice and rice products. Despite the recent interest in this topic and limited work by the US FDA to test arsenic levels in rice, metal concentrations in rice bran oils have remained unexplored. In this work, we offer a complete characterization of crude and refined rice bran oils, including analysis of arsenic, lead, mercury, cadmium, and zinc. This work explores the utility of different ICP methods for heavy metals analysis, and the work described here may provide context for much of the recent press surrounding metal contaminants in rice. Heavy metal concentrations in eight different rice bran oils (µg/g). The relative sizes of metal ions are proportional to their most common ionic radius. [ABSTRACT FROM AUTHOR]

Engineered nanoparticles (NPs) and natural organic matter (NOM) in the environment may interact with background contaminants such as heavy metals and modify their bioavailability and toxicity. In the present study, the combined influences of 2 common NPs (TiO2 and CeO2) and humic acid (HA; as a model NOM) on Cu(II) phytotoxicity to rice were investigated by a 3-d root elongation assay performed on filter paper media. The results showed that the adsorption coefficients of bare TiO2 and CeO2 NPs (100 mg/L) toward Cu2+ are 2.65 and 4.37, respectively, at an initial concentration of 10 mg/L, suggesting that Cu(II) could be strongly adsorbed by NPs, whereas HA-coated TiO2 and CeO2 NPs further enhanced the adsorption coefficients to 4.37 and 6.85, respectively. In addition, compared with Cu-alone treatment, the addition of bare TiO2 and CeO2 NPs (1000 mg/L) increased the length of rice root by 32.5% and 39.0%, respectively; however, the presence of HA-coated TiO2 and CeO2 NPs increased the root length by 90.2% and 100.1%, respectively, which indicated that the mitigation effect of HA-coated NPs on Cu(II) phytotoxicity was more visible than that of bare NPs. The results demonstrated that coexistence of NPs and HA significantly alleviated Cu(II) phytotoxicity as a result of a decrease in bioavailable soluble Cu(II) concentration, which contributes to an understanding of the potential behavior of NPs in the environment. Environ Toxicol Chem 2015;34:1588-1596. © 2015 SETAC [ABSTRACT FROM AUTHOR]

The feasibility of prediction of cadmium (Cd) content in brown rice was investigated by near-infrared spectroscopy ( NIRS) and chemometrics techniques. Spectral pretreatment methods were discussed in detail. Synergy interval partial least squares (si PLS) algorithm was used to select the efficient combinations of spectral subintervals and wavenumbers during constructing the quantitative calibration model. The performance of the final model was evaluated by the use of root mean square error of cross-validation ( RMSECV), root mean square error of prediction ( RMSEP) and correlation coefficients for calibration set and prediction set ( Rc and Rp), respectively. The results showed that the optimum si PLS model was achieved when two spectral subinterval and fifty-two variables were selected. The predicted result of the best model obtained was as follows: RMSECV = 0.232, Rc = 0.930, RMSEP = 0.250 and Rp = 0.915. Compared with PLS and interval PLS models, si PLS model was slightly better than those methods. These results indicate that it is feasible to predict and screen Cd content in brown rice using NIRS. [ABSTRACT FROM AUTHOR]

An ultrasound-assisted dispersive liquid–liquid microextraction based on solidification of a floating organic drop method followed by high-performance liquid chromatography was developed for the extraction, preconcentration, and determination of trace amounts of organophosphorus pesticides in rice samples. Variables affecting the performance of both steps were thoroughly investigated. Some effective parameters on extraction were studied and optimized. Under the optimum conditions, recoveries for rice sample are in the range of 58.0–66.0%. The calibration graphs are linear in the range of 4–800 µg/kg and, limits of detection and limits of quantification are in the range of 1.5–3 and 4.2–8.5 µg/kg, respectively. The relative standard deviation for 50.0 µg/kg of organophosphorus pesticides in rice sample are in the range of 4.4–5.1% (n = 5). The obtained results show that proposed method is a fast and simple method for the determination of pesticides in cereals. [ABSTRACT FROM AUTHOR]

BACKGROUND Zinc deficiency is prevalent among children and women in Bangladesh and parboiled rice is the major staple food consumed. Parboiling offers an opportunity to increase the zinc and iron content of rice by adding fortificants to the soaking water. RESULTS Rice zinc content increased with increasing amounts of zinc sulfate added to the parboil soaking water. Addition of 1300 mg zinc L−1 increased raw polished rice zinc content from 16.6 to 44.9 mg kg−1 and from 12.6 to 32.9 mg kg−1 in the open and closed parboiling systems, equivalent to 170% and 161% increases, respectively. Retention of zinc after washing and cooking was 70-81% across all concentrations tested. Addition of iron-ethylenediaminetetraacetic acid and zinc sulfate together increased zinc, but not iron, content of polished rice. The simulated prevalence of inadequate zinc intake was reduced by more than half among children and nearly two-thirds among women if 50% of the population were to consume the 1300 mg zinc L−1 parboiled fortified rice. CONCLUSION Addition of zinc sulfate to soaking water during parboiling increases the zinc content of rice and, if found to be bioavailable, could substantially reduce the prevalence of inadequate zinc intake by children and women in Bangladesh. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of this study was to estimate the reference level of cadmium in rice as the benchmark doses (BMD) and their 95% lower confidence limits (BMDL) for various renal effects by applying an updated hybrid approach. The participants were 1120 men and 1274 women aged 50 years or older who lived in the environmentally exposed Kakehashi river basin for at least 30 years. As indicators of renal dysfunction, glucose, protein, aminonitrogen, metallothionein and β2-microgrobulin in urine were measured. Cadmium concentration was determined for rice samples stored in warehouses of the farmers in all of the polluted hamlets. The BMD and BMDL that corresponded to an additional risk of 5% were calculated with background risk at a zero exposure set at 5%. The obtained BMDLs were 0.39 (aminonitrogen), 0.26 (metallothionein), 0.25 (β2-microgrobulin) mg kg-1 in men and 0.44 (glucose), 0.32 (protein), 0.33 (aminonitrogen), 0.28 (metallothionein) and 0.24 (β2-microgrobulin) mg kg-1 in women. The lowest BMDL was 0.25 and 0.24 mg kg-1 (β2-microgrobulin) in men and women respectively. These values were lower than the maximum level (0.4 mg kg-1) determined by the Codex Alimentarius Commission, indicating that these BMDLs may contribute to further discussion on the health risk assessment of cadmium exposure. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The molecular mechanism to control the oxidative burst exerted by Mn accumulation in rice ( Oryza sativa L.) plants, grown in hydroponics containing 0.5, 2 and 8 mg l-1 Mn and irradiated with a total biological effective UV-B irradiation of 20.825 kJ m−2, was investigated in the chloroplasts at the 15th and 21st days after germination. In both experimental periods, Mn accumulation kinetics in the leaves and in the chloroplast lamellae displayed overall increases. Coupled to higher membrane selectivity, superoxide production and acyl lipids peroxidation in the thylakoids decreased, prompting upper rates of the Hill and Mehler reactions. Connected to UV-B irradiation, higher accumulated Mn in thylakoids was found to be chelated in a 36.5 kDa protein, with Mn/protein ratio of about 1 and high content of Gln, Asp, Glu, Leu and Gly, being its EPR spectrum characteristic of high-spin Mn(II), in a S = 5/2 ground state. As this protein exhibited enzymatic catalysis of superoxide dismutation, it was concluded that, under UV-B irradiation, the high internal tolerance of Oryza sativa L. to Mn during the vegetative growth also triggers the synthesis of a manganese protein that mimics superoxide dismutase functioning, therefore furnishing an additional intimate protection against oxidative stress. [ABSTRACT FROM AUTHOR]

BACKGROUND Two cultivars of black rice were investigated for the effects of different cooking methods on anthocyanins, total phenolic compounds and antioxidant activities. RESULTS There was a significant loss of anthocyanins during cooking: roasting resulted in the greatest decrease (94%), followed by steaming (88%), pan-frying (86%) and boiling (77%). Contents of phenolic compounds decreased drastically after cooking, with significantly lower retention in the black rice cultivar that had higher amylose content. DPPH radical-scavenging activity of black rice decreased after cooking. In contrast, metal-chelating activity increased significantly after cooking. Anthocyanins showed a high positive correlation with total phenolic compounds ( r2 = 0.936) but a significant negative correlation with metal-chelating activity ( r2 = 0.6107). CONCLUSION The results indicate that cooking degraded anthocyanins and other phenolic compounds, but with a concomitant increase in phenolics from possible degradation of anthocyanins, which resulted in the enhancement of metal-chelating activity. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Fortified rice holds great potential for bringing essential micronutrients to a large part of the world population. However, it is unknown whether differences in cooking methods or in production of rice premix affect the final amount of micronutrient consumed. This paper presents a study that quantified the losses of five different micronutrients (vitamin A, iron, zinc, folic acid, and vitamin B12) in fortified rice that was produced using three different techniques (hot extrusion, cold extrusion, and coating) during cooking and five different cooking methods (absorption method with or without soaking, washing before cooking, cooking in excess water, and frying rice before cooking). Fortified rice premix from six different producers (two for each technique) was mixed with normal rice in a 1:100 ratio. Each sample was prepared in triplicate, using the five different cooking methods, and retention of iron, zinc, vitamin A, vitamin B12, and folic acid was determined. It was found that the overall retention of iron, zinc, vitamin B12, and folic acid was between 75% and 100% and was unaffected by cooking method, while the retention of vitamin A was significantly affected by cooking method, with retention ranging from 0% (excess water) to 80% (soaking), depending on the cooking method and producer of the rice premix. No systematic differences between the different production methods were observed. We conclude that different cooking methods of rice as used in different regions of the world do not lead to a major loss of most micronutrients, with the exception of vitamin A. The factors involved in protecting vitamin A against losses during cooking need to be identified. All production techniques of rice premix yielded similar results, showing that coating is not inferior to extrusion techniques. Standard overages (50%) for vitamin B12 and folic acid are too high. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive review of the currently available technologies for vitamin and mineral rice fortification. It covers currently used technologies, such as coating, dusting, and the various extrusion technologies, with the main focus being on cold, warm, and hot extrusion technologies, including process flow, required facilities, and sizes of operation. The advantages and disadvantages of the various processing methods are covered, including a discussion on micronutrients with respect to their technical feasibility during processing, storage, washing, and various cooking methods and their physiological importance. The microstructure of fortified rice kernels and their properties, such as visual appearance, sensory perception, and the impact of different micronutrient formulations, are discussed. Finally, the article covers recommendations for quality control and provides a summary of clinical trials. [ABSTRACT FROM AUTHOR]

Fortification of staple foods and commonly used condiments with vitamins and minerals has been considered one of the most cost-effective interventions to prevent and control micronutrient deficiencies. Because of its wide local consumption, acceptability, reach, and quantum of consumption, rice ( Oryza sativa) far exceeds the requirements of a staple food vehicle that can be considered for fortification purposes at a population-level intervention. The World Health Organization (WHO) has the mandate to develop evidence-informed guidelines for the fortification of staple foods as a public health intervention, including rice fortification with micronutrients. The WHO, in collaboration with the Global Alliance for Improved Nutrition (GAIN), convened a consultation on 'Technical Considerations for Rice Fortification in Public Health' in Geneva, Switzerland on October 9-10, 2012 to provide technical inputs to the guideline development process, particularly with reference to feasibility and implementability. The industrial and regulatory technical considerations in rice fortification, as well as the considerations for implementing it as a public health strategy and assuring equitable access and universal coverage, were reviewed in this consultation. This paper summarizes the discussions and priority research areas for the forthcoming years. [ABSTRACT FROM AUTHOR]

Increase in the atmospheric carbon dioxide concentration ([CO2]) enhanced the concentration of carbohydrates in rice grains, according to results of a previous study. However, its impact on other quality traits is little known. To investigate the effect of CO2 levels (375 and 550 μmol/mol) on rice quality, a field experiment was conducted with open‐top chambers. Elevated [CO2] affected several nutritional parameters of the grain. Whereas the concentration of α‐linolenic acid increased, that of linoleic and γ‐linolenic acids decreased. For example, reductions of 9 and 28% were observed for linoleic acid in the brown rice and for γ‐linolenic acid in the husk, respectively. Phytic acid concentration and zinc bioavailability were unaffected. Whereas iron bioavailability decreased in the brown rice (22%), calcium bioavailability increased in the bran and husk (5–11%). The concentrations of essential amino acids were also reduced; for example, the amount of isoleucine in the white rice, tyrosine in the brown rice, and phenylalanine in the bran decreased by 40, 57, and 23%, respectively. In contrast, elevated [CO2] resulted in improved grain whiteness (3%) and starch viscosity (11%), with no effect on the milling quality. These data indicate that increased [CO2] has both positive and negative effects on quality, depending on the specific end use of the rice grain. [ABSTRACT FROM AUTHOR]

Vacuum drying was employed with a vacuum impregnation technique in a semidry state to enrich rice with antioxidants of beetroot juice. The properties of the vacuum‐dried raw and cooked rice grains were characterized. The various raw rice grains (three varieties and two storage time periods) exhibited a significant absorption of beetroot juice, which was evident from the red‐violet beetroot color of the rice, as distinguished from the white color of the control. The color increase (ΔE= 20−40) was linear with the juice content (R2 = 0.96−0.99). Their total phenolic (TP) contents and 2,2‐diphenyl‐2‐picrylhydrazyl radical (DPPH) scavenging activities were enhanced (ΔTP = 21−260 mg of gallic acid equivalents/100 g of rice db and ΔDPPH = 22−64 mg of vitamin C equivalents/100 g of rice db). Their grain integrity was reduced (Δforce = −1 to −63), which was potentially associated with the formation of grain surface cracks (linear relationship of %crack and %juice with R2 = 0.94−0.98). After cooking, the enriched rice grains were linearly elongated with added juice (R2 = 0.88−0.97, up to 1.6‐, 2.0‐, and 2.0‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively), and the overall volume of the cooked rice was increased (likely not linear, up to 3.2‐, 4.3‐, and 4.8‐fold for Sanpatong 1, Khao Dawk Mali 105, and Chainart 1 rice samples, respectively). Such improvements in cooking qualities were obtained by this simple vacuum‐drying technique, in comparison to existing rice‐aging processes that are more time consuming. The sensorial scores of the resultant rice products were excellent. Vacuum drying is an effective tool to improve the antioxidant value of rice as well as its cooking quality, and the raw quality remains appreciable. It is a simple and rapid process that could be practical for manufacturing healthy rice products. [ABSTRACT FROM AUTHOR]

RATIONALE Sake is made from fermented rice and has been drunk in Japan for more than 1000 years. The rice must be polished prior to fermentation to obtain high-quality sake. It is traditionally recognized that the quality of sake is improved as the rice polishing ratio (percentage removed in the polishing process) increases. However, the underlying chemistry of the rice polishing process is incompletely understood. Herein, we analyzed the distribution of lysophosphatidylcholine (LPC) molecular species with unsaturated fatty acids in rice, as their presence is thought to exert a negative effect on the flavor of sake. METHODS The distribution of LPC molecular species in rice was visualized via matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). RESULTS LPC (16:0) is ubiquitously present in the endosperm of rice while LPC (18:0) is localized in the core of the endosperm. In contrast, LPC (18:2) and LPC (18:1) are present in the outer region of the endosperm. CONCLUSIONS The enhancement of the quality of sake as the polishing ratio of the rice increases might be explained in terms of the distribution of LPC with unsaturated fatty acids in the rice. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Glutinous rice saccharification was performed with α-amylase, glucoamylase, a two-enzyme combination or wheat qu. Experiments were carried out at two locations, with rice from two sources and in different fermentation temperatures. The main products were first identified and then measured by high-performance liquid chromatography. Low-order kinetic model structures (constructs of model with adjustable reaction rates) were derived based on the major chemical reactions brought about by different enzymes. The model structures were then tested for their abilities to capture the main kinetic variations after optimization of reaction rates by a least square algorithm. The model structures were found useful in representing the measured kinetic variations with one exception. The estimated reactions rates correctly reflected the variations observed from the experiments and provided insights into the reaction processes in terms of reaction speeds, dominant variations and primary products. The actions of α-amylase and wheat qu differed from findings in prior research. The proposed model structures show promise for describing the saccharification process of glutinous rice. Practical Applications Rice is routinely hydrolyzed as part of the processes to produce wines, alcohols, amino acids and other products. This research provides a set of model structures that are simple enough for practical use and still capture the main kinetic behaviors of the saccharification process with enzymes often used in industry. The model structures are needed by food process engineers in their efforts to analyze, optimize and develop controls for many industrial processes that involve rice saccharification. [ABSTRACT FROM AUTHOR]

Little is known regarding the impact of elevated carbon dioxide concentration ([CO2]) on the chemical composition of rice grains. A field experiment was conducted with open‐top chambers with rice (Oryza sativa L. cv. Ariete) grown at two levels of atmospheric CO2 (375 and 550 μmol/mol), and their effects were monitored on the proximate composition and carbohydrate contents of the grains. Following exposure to elevated [CO2], soluble dietary fiber increased by 136, 82, and 77% in brown rice, white rice, and bran, respectively. Increases of a lower magnitude (8%) were observed for insoluble dietary fiber in the bran and brown rice. For all 10 sugars identified, there was a trend for increasing their content. For example, increases of 135% were recorded for glucose in the white rice. In all rice milling fractions, elevated [CO2] reduced the protein (4–15%) and amylose (6–16%) contents, with no effect on the ash, starch, and gross energy contents. The fat content was increased by elevated [CO2] in the white rice (23%) and tended to decrease in the bran (9%). It is concluded that besides yield, increased dietary fiber might be another positive effect of high levels of atmospheric CO2 expected by the middle of the current century. [ABSTRACT FROM AUTHOR]

Starch is the most widespread form of energy storage in the plant kingdom. Although many enzymes and related factors have been identified for starch biosynthesis, unknown players remain to be identified, given that it is a complicated and sophisticated process. The endosperm of rice ( Oryza sativa) has been used for the study of starch synthesis. Here, we report the cloning and characterization of the FLOURY ENDOSPERM6 ( FLO6) gene in rice. In the flo6 mutant, the starch content is decreased and the normal physicochemical features of starch are changed. Significantly, flo6 mutant endosperm cells show obvious defects in compound granule formation. Map-based cloning showed that FLO6 encodes a protein of unknown function. It harbors an N-terminal transit peptide that ensures its correct localization and functions in the plastid, and a C-terminal carbohydrate-binding module 48 ( CBM48) domain that binds to starch. Furthermore, FLO6 can interact with isoamylase1 ( ISA1) both in vitro and in vivo, whereas ISA1 does not bind to starch directly. We thus propose that FLO6 may act as a starch-binding protein involved in starch synthesis and compound granule formation through a direct interaction with ISA1 in developing rice seeds. Our data provide a novel insight into the role of proteins with the CBM48 domain in plant species. [ABSTRACT FROM AUTHOR]

Background To increase rice production in Africa, considerable research has focused on creating interspecific hybrids between African ( Oryza glaberrima Steud.) and Asian ( O. sativa L.) rice in an attempt to obtain the positive attributes of each in new cultivars. Since flavor is a key criterion in consumer acceptance of rice, as an initial inquiry we characterized and compared the aroma chemistry of selected cultivars of African O. sativa ssp. japonica, O. sativa ssp. indica, O. glaberrima, and their interspecific hybrids grown in West Africa, using gas chromatography-mass spectrometry, gas chromatography-olfactometry and descriptive sensory analysis. Results Of 41 volatiles identified across seven representative rice cultivars grown in West Africa, 3,5,5-trimethyl-2-cyclopenten-1-one, styrene, eucalyptol, linalool, myrtenal and l- α-terpineol had not been previously reported in rice. Thirty-three odor-active compounds were characterized. 4-Ethylphenol and ( E, E)-2,4-heptadienal were unique to O. glaberrima, and pyridine, eucalyptol and myrtenal were described only in an interspecific hybrid. Descriptive sensory analysis indicated 'cooked grain', 'barny' and 'earthy' attributes were statistically different among the cultivars. Conclusion The aroma chemistry data suggest that it should be possible to separate African cultivars into distinct flavor types thereby facilitating selection of new cultivars with superior flavor in African rice breeding programs. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Mutations in the photorespiration pathway display a lethal phenotype in atmospheric air, which can be fully recovered by elevated CO2. An exception is that mutants of peroxisomal hydroxypyruvate reductase (HPR1) do not have this phenotype, indicating the presence of cytosolic bypass in the photorespiration pathway. In this study, we constructed overexpression of the OsHPR1 gene and RNA interference plants of OsHPR1 and OsHPR2 genes in rice (Oryza sativa L. cv. Zhonghua 11). Results from reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and enzyme assays showed that HPR1 activity changed significantly in corresponding transgenic lines without any effect on HPR2 activity, which is the same for HPR2. However, metabolite analysis and the serine glyoxylate aminotransferase (SGAT) activity assay showed that the metabolite flux of photorespiration was disturbed in RNAi lines of both HPR genes. Furthermore, HPR1 and HPR2 proteins were located to the peroxisome and cytosol, respectively, by transient expression experiment. Double mutant hpr1-hpr2 was generated by crossing individual mutant of hpr1 and hpr2. The phenotypes of all transgenic lines were determined in ambient air and CO2-elevated air. The phenotype typical of photorespiration mutants was observed only where activity of both HPR1 and HPR2 were downregulated in the same line. These findings demonstrate that two hydroxypyruvate reductases encoded by OsHPR1 and OsHPR2 are involved in photorespiratory metabolism in rice. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is widely considered to be caused by amyloid‐β peptide (Aβ) accumulation in the brain. Aβ is excised from amyloid‐β precursor protein through sequential cleavage by β‐secretase 1 (BACE1) and γ‐secretase. Thus, BACE1 inhibition could prevent Aβ accumulation. Here, we identified myo‐inositol hexakisphosphate (IP6) as a BACE1 inhibitory molecule in rice grain extract and digest. The rice digest and IP6 significantly inhibited Aβ production in neuroblastoma cells without cytotoxicity. These results suggested that rice components, including IP6, may be promising starting materials for the development of potent and safe drugs and/or food to prevent AD. [ABSTRACT FROM AUTHOR]

Ferulic and p‐coumaric acids were analyzed in 50 rice (Oryza sativa L.) samples from 32 cultivars harvested in Japan. In brown rice, ferulic and p‐coumaric acid levels ranged from 309 to 607 mg/kg and from 49 to 100 mg/kg, respectively. In 70% polished rice, ferulic and p‐coumaric acid levels ranged from 27 to 103 mg/kg and from 0.4 to 3.5 mg/kg, respectively. Ratios of average phenolic acid levels in the 70% polished rice to the brown rice were 13.9% for ferulic acid and 1.9% for p‐coumaric acid. The ferulic acid level was highly correlated between brown and 70% polished rice (R = 0.815; P < 0.01), but there was no clear correlation for p‐coumaric acid. Phenolic acid levels in the 70% polished rice did not show any clear correlations between the analytical index measurements for sake brewing suitability (weight of 1,000 grains, water absorption, digestibility, crude protein, and potassium content). Phenolic acid levels in the 70% polished rice directly affected levels in the rice koji enzyme digest. The results indicated that phenolic acid levels in sake were affected by the levels in ingredient rice grains, which may then influence the sensory quality of sake. [ABSTRACT FROM AUTHOR]

Soft rice with low amylose content ( AC) ranging by 5-15% is a unique type with special eating and appearance quality and has become popular in the rice market. We resequenced the Wx-mp, a key allele from Milky Princess, a Japanese low AC variety, and found that the +473 mutation in exon 4 is the key mutation in both Wx-mp and its ancestor allele, Wx-mq from Milky Queen. Based on this functional mutation, an allele-specific PCR ( AS- PCR) marker was developed and proven in a breeding population derived from a cross between a Chinese late variety Nan Keng 46 ( Wx-mp/ Wx-mp) and an early line Ning 63121( Wx-b/ Wx-b). Based on the marker-aided selection by our newly developed AS- PCR marker for Wx-mp and the known ST10 marker for Stvb-i, a total of 12 Wx-mp homozygotes were selected from 198 F2 progenies, and four of them were immune to rice stripe virus ( RSV) with averagely 11.3 days earlier heading than Nan Keng 46 without significant change in grain yield. [ABSTRACT FROM AUTHOR]

This study determined the levels of nutritionally important starch fractions in selected milled, nonparboiled rice cultivated in Nigeria. Five improved varieties ( FARO 52, FARO 57, FARO 44, FARO 60 and FARO 61) and four local varieties ( Kwandala, Yardass, Jeep and Jamila) were evaluated. There were significant differences in starch fractions among varieties. Resistant starch ( RS) ranged between 1.43% and 3.13%. Rapidly digestible starch ( RDS) was lowest in Jamila (27.70%) and highest in FARO 61 (39.26%). Generally, the local varieties had significant higher RS (2.71%) with a lower RDS (32.82%) compared with improved varieties ( RS; 1.88% and RDS; 36.07%). RS was inversely related to RDS and starch digestion index ( SDI). The SDI had a highly significant positive correlation with RDS ( r = 0.879, P < 0.01). These results highlight the need for further work in the identification of milled, nonparboiled rice varieties with less rapid digestion for its associated health benefits to consumers. [ABSTRACT FROM AUTHOR]

Protein is the second most abundant constituent in the rice grain next to starch. Association analysis for protein concentration in brown rice was performed using a “mini‐core” collection, which represents the germplasm diversity found in the USDA rice world collection. Protein concentration was determined in replicated trials conducted in two southern U.S. locations, and association mapping was performed by using 157 genomewide DNA markers. Protein concentration ranged from 5.4 to 11.9% among the 202 accessions. Protein variation owing to accession and accession × location interaction were highly significant. Ample variation was seen within each subpopulation by ancestry, as well as within the 14 geographic regions where the accessions originated. Accessions from Eastern Europe had the highest level of protein. Ten markers on eight chromosomes were significantly associated with protein concentration. Five of these markers occurred near known protein precursor genes or quantitative trait loci, and the other five markers were novel for the association with protein concentration in rice. The germplasm and genetic markers identified in this study will assist breeders in developing cultivars tailored for applications requiring specific protein concentration in the rice grain. The research results contribute to the potential discovery of novel rice storage protein pathways in the endosperm. [ABSTRACT FROM AUTHOR]

Influences of the conditions of raw rice storage and cooking on parameters related to colour and antioxidant activities of organic hulled red fragrant rice were investigated. Raw rice samples were vacuum-packed in oriented polypropylene/aluminium/linear low-density polyethylene or nylon/linear low-density polyethylene pouches and stored at ambient temperature or 15 °C up to 12 months. Cooked samples were prepared from aged raw samples. Kernel colour, total anthocyanin content ( TAC) of acidic methanolic extracts as well as total phenolic content ( TPC), reducing power ( RP) and radical scavenging activity ( RSA) of methanolic extracts and enzymatically digested samples were maintained during 12-month storage, regardless of packaging materials and storage temperatures. Cooked kernels had larger L value, lower a and b values, and greater TAC (dry basis), comparing with the raw rice. Cooking caused drastic decrease in TPC, RP and RSA of methanolic extracts. Nevertheless, less negative impacts of cooking were found for enzymatically digested samples. [ABSTRACT FROM AUTHOR]

Multi-micronutrient-fortified rice could be an effective and sustainable approach to combat micronutrient deficiencies. We produced hot-extruded artificial rice grains fortified with 10 mg iron (as micronised ground ferric pyrophosphate), 5 mg zinc (as oxide, sulphate or carbonate) and 750 μg vitamin A/g [as retinyl palmitate (RP)] and measured RP stability. The rice was designed to be mixed 1:200 with natural rice. Mean RP losses were 5.3% during extrusion, 28.5% during storage and 9.8% during cooking. Storage losses after 18 weeks at 30 °C in plastic packages exposed to light were ca 40% with iron and zinc causing no further losses. In aluminium packages (no light), mean RP losses were ca 20%. Iron, but not zinc, increased RP degradation. Zinc sulphate increased the negative effect of iron. The relatively good stability of RP during hot extrusion can be explained by the closed surface and dense nature of the artificial grain protecting RP from oxidation. [ABSTRACT FROM AUTHOR]