Stages Of Grain Development Research Articles

Japanese Sake‐Brewing Rice Cultivars Show High Levels of Globulin‐like Protein and a Chloroplast Stromal HSP70

ABSTRACTWhite‐core is an important trait in the selection of rice (Oryza sativa L. ssp. japonica) for sake (Japanese rice wine) production. The present study was conducted to find differences between the endosperm protein pattern of white‐core–bearing sake‐brewing cultivars and those of normal rice grains. Protein patterns of white‐core sake‐brewing grains were compared with those of normal cultivars by two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE). Several proteins showing different amounts were detected. These were identified by microsequencing and found to be known carbohydrate‐metabolizing enzymes as well as proteins with no known involvement in carbohydrate metabolism. Two units of globulin‐like protein (GLP) and a chloroplast stromal heat shock protein 70 (ctHSP70) showed the greatest difference in the white‐core group. Analysis of amyloplast proteins showed slightly higher amounts of GLP and ctHSP70 in the amyloplast than in the cytosol. Also, time‐course analysis of developing rice grains indicated that both proteins were elevated during the later stages of grain development. From this we conclude that GLP and ctHSP70‐II are associated with white‐core appearance and thus behave as biochemical markers for this character in sake‐brewing rice cultivars.

Accumulation of lipoproteins in Chinese winter wheat cultivars and their impact on dough mixing characteristics

The changes in the accumulation of lipoproteins, the relationship between lipoproteins and the dough mixing characteristics of Chinese winter wheat (Triticum aestivum L.) were investigated for six cultivars that differ in quality characteristics and was classified into three groups according to their gluten index. All cultivars were grown under the same experimental field conditions, with three replicates. The lipoproteins were found to accumulate during the early stages of grain development. The rate of lipoproteins’ accumulation appeared to follow a similar pattern of marked increase during the time from 5 DAA (days after anthesis) to 15 DAA, with a peak at 15 DAA, then quickly decreased for the same group of cultivars. Different patterns appeared from 20 DAA until maturity, but those cultivars with medium quality gluten showed a significant decrease during this period. Significant differences were found in lipoproteins for the six cultivars during grain development on the same days after anthesis. Correlation analysis indicated that lipoproteins from 25 DAA to 30 DAA were positively correlated with dough mixing parameters. However, the correlation coefficients were not statistically significant.

Grain Sink Strength Related to Carbon Staying in the Leaves of Hybrid Wheat XN901

XN901 is a K-type three-line hybrid wheat with a high yield potential, and its leaves and stem remaining green during grain maturation, suggesting much assimilate stay in leaves and stem. The grain water content, grain volume, carbohydrate content, and enzyme activity of sucose metabolism in the grain, as well as source-sink relationship were studied in order to investigate the physiological reason of the assimilate remaining in leaves and stem at the late stage. The results showed that the hybrid grains had more water and soluble sugar, higher activities of acid invertase and sucrose synthase at the early stage that led to a faster expansion growth, greater grain volume and faster starch synthesis at the early to mid stage of grain development. Also it had a longer period for actively filling. As a result, the grain weight and yield of the hybrid were increased by 14 and 15% respectively compared to that of Shaan 229. Additionally, the biomass of XN901 was 41.7% more than that of control, but its harvest index was 9% lower than Shaan 229. However, its lower activity of sucrose synthase indicated a lower sink activity at the late stage, resulting in a slow rate of filling and starch synthesis. Also, the hybrid wheat XN901 had a large source-sink ratio. It is the main reason for much assimilate remaining in the straw at the late stage and lower harvest index. Strengthening the sink activity and raising the harvest index should be the key means of improving the yield of hybrid wheat.

Analysis of the (1,3)-β- d-glucan synthase gene family of barley

Callose consists mostly of (1,3)-β- d-glucan and is synthesised in many plant tissues during growth and development, where it is believed to play a fundamental role in cell plate formation during cell division. Callose deposition also represents an important response to pathogen attack, wounding and to various abiotic stresses. Here, the transcription patterns of members of the callose synthase gene family from barley ( Hordeum vulgare) were defined. Thus, fragments of six barley (1,3)-β- d-glucan synthase-like ( GSL) cDNAs were obtained by PCR amplification using primers designed to barley expressed sequence tag (EST) sequences. The HvGSL genes, designated HvGSL2 to HvGSL7, were mapped to individual loci that were distributed across the barley genome on chromosomes 3H, 4H, 6H and 7H. The HvGSL1 gene has been isolated and characterised previously. Transcript levels for all the genes were analysed by quantitative real-time PCR in a range of barley tissues and organs, at various developmental stages. High levels of transcript for many of the HvGSL genes were detected in endosperm during the early stages of grain development, when cellularisation of the endosperm was occurring and it is likely that many of the genes participate in this process. Transcripts of HvGSL1 and HvGSL5 mRNAs were significantly more abundant than other GSL mRNAs in the roots of young seedlings, while HvGSL7 mRNA was detected at relatively high levels along the length of two week old shoots.

The effect of rainfall and temperature on the preharvest sprouting tolerance of winter wheat in the dryland production areas of the Free State Province

Preharvest sprouting (PHS) is a risk factor in winter cereal farming in certain environments as even mild sprouting affects the suitability of wheat for end-use products. This is because even mild sprouting affects the suitability of wheat for end-use products. The extent of PHS is hard to predict. To establish a quantitative relationship between PHS and different climatic characteristics, eighteen winter wheat cultivars were planted in three regions representative of the wheat growing conditions of the Free State Province of South Africa over four years. Climatic characteristics during six environmental periods were investigated, namely planting to harvest (PH), anthesis to harvest (AH), grain filling (GF), 14 days prior to physiological maturity (14M) and 10 and 20 days prior to harvest (10H and 20H) respectively. These data sets were correlated with PHS resistance determined in a rain simulator to determine if climate during various stages of grain development had an effect on the expression of dormancy and subsequent PHS. Principal component analysis (PCA) on mean PHS values identified three distinct groupings of cultivars, ranging from PHS susceptible to PHS resistant. A fairly strong positive correlation ( r = 0.715, P = 0.008) was found between PHS and minimum temperature during grain filling. Large variations in PHS values were also observed between the various cultivars, indicating that certain cultivars, such as Caledon, Gariep, Limpopo, Matlabas, PAN 3118, PAN 3120, PAN 3377 and SST 334, are more sensitive to environmental effects than others and that the variation in cultivar PHS is not consistent across sites and years.

Effect of high temperature on albumin and globulin accumulation in the endosperm proteome of the developing wheat grain

The accumulation of KCl-soluble/methanol-insoluble albumins and globulins was investigated in the endosperm of developing wheat ( Triticum aestivum, L. cv. Butte 86) grain produced under a moderate (24 °C/17 °C, day/night) or a high temperature regimen (37 °C/28 °C) imposed from 10 or 20 days post-anthesis (dpa) until maturity. Proteins were separated by 2-DE and developmental profiles for nearly 200 proteins were analyzed by hierarchical clustering. Comparison of protein profiles across physiologically equivalent stages of grain fill revealed that high temperature shortened, but did not substantially alter, the developmental program. Accumulation of proteins shifted from those active in biosynthesis and metabolism to those with roles in storage and protection against biotic and abiotic stresses. Few proteins responded transiently when plants were transferred to the high temperature regimens, but levels of a number of proteins were altered during late stages of grain development. Specific protein responses depended on whether the high temperature regimens were initiated early or mid development. Some of the heat responsive proteins have been implicated in gas bubble stabilization in bread dough and others are suspected food allergens.

Concentration of ergosterol in small-grained naturally contaminated and inoculated cereals

AbstractErgosterol (ERG) is a major sterol constituent of most fungi. Its concentration is negligible in higher plants, but can be used as a chemical marker of the presence of fungal contaminations. In this study, ERG concentration was assessed in randomly collected samples of naturally contaminated grain (wheat, barley and oat) and in samples of grain (wheat, barley, triticale and oat) harvested after inoculation of heads with conidia of different Fusarium species. Wheat samples were analysed at three stages of grain development. The lowest ERG concentration was found in non-inoculated samples at the first stage of grain development. This concentration was increasing with grain ripening. In naturally contaminated samples collected after harvest, ERG concentration was lower in wheat than in barley and oat. ERG concentrations in inoculated samples varied significantly, but were always significantly higher than in naturally contaminated samples. In the above cereal samples it was much lower than the levels assayed in laboratory cultures inoculated with fungi from genus Fusarium. The content of ERG was also analyzed in milling products of small-grained cereals and other foodstuffs, where a considerable variation was observed. The lowest ERG amounts were assayed in flours with a high degree of purification, while the highest ones in case of flours and products with a low purification rate. The results indicate the potential application of HPLC combined with microwave-assisted extraction both when assaying samples with low ERG concentrations (naturally contaminated) and those characterized with high contents of fungal biomass (strongly infected, artificially inoculated). It also facilitates analyses of fungal biomass in technological processes, where results may be expected to vary considerably.

Identification and genetic mapping of variant forms of puroindoline b expressed in developing wheat grain

Transcripts encoding three novel variant forms of puroindoline b have been identified in developing seeds of wheat. These show 57–60% sequence identity with the wild type form of Pin b but all lack one of the three tryptophan residues present in the “tryptophan loop” region of the wild type protein. Counts of ESTs and array analysis indicate that the transcripts encoding variant forms of Pin b are about an order of magnitude less abundant than those encoding wild type Pin b while array analysis also shows that expression of the variant form 1 declines more rapidly than that of the wild type form during the later stages of grain development. The gene(s) encoding variant form 1, named Pinb-A2, were mapped to the long arm of chromosome 7A of bread wheat where they show linkage to novel QTLs for hardness which have been identified in two doubled haploid populations derived from crosses between hard parental cultivars (Shamrock × Shango, Malacca × Charger).

Differential regulation of grain sucrose accumulation and metabolism in Coffea arabica (Arabica) and Coffea canephora (Robusta) revealed through gene expression and enzyme activity analysis

* Coffea arabica (Arabica) and Coffea canephora (Robusta) are the two main cultivated species used for coffee bean production. Arabica genotypes generally produce a higher coffee quality than Robusta genotypes. Understanding the genetic basis for sucrose accumulation during coffee grain maturation is an important goal because sucrose is an important coffee flavor precursor. * Nine new Coffea genes encoding sucrose metabolism enzymes have been identified: sucrose phosphate synthase (CcSPS1, CcSPS2), sucrose phosphate phosphatase (CcSP1), cytoplasmic (CaInv3) and cell wall (CcInv4) invertases and four invertase inhibitors (CcInvI1, 2, 3, 4). * Activities and mRNA abundance of the sucrose metabolism enzymes were compared at different developmental stages in Arabica and Robusta grains, characterized by different sucrose contents in mature grain. * It is concluded that Robusta accumulates less sucrose than Arabica for two reasons: Robusta has higher sucrose synthase and acid invertase activities early in grain development - the expression of CcSS1 and CcInv2 appears to be crucial at this stage and Robusta has a lower SPS activity and low CcSPS1 expression at the final stages of grain development and hence has less capacity for sucrose re-synthesis. Regulation of vacuolar invertase CcInv2 activity by invertase inhibitors CcInvI2 and/or CcInvI3 during Arabica grain development is considered.

Effect of water stress at different stages of grain development on the characteristics of starch and protein of different wheat varieties

The effect of water stress (WS) at 8 and 15 days post anthesis (DPA) on the characteristics of starch and protein separated from C-306, HD-2329, PBW-175, PBW-343 and NI-5439 wheat varieties was studied. WS-induced changes in A-, B- and C-type granules distribution were variety- and stage-dependent. A-type granules increased in response to WS at both stages in all varieties, the extent of increase being greater at 15 DPA. The proportion of B-type granules decreased in all the varieties, except C-306, in response to WS at 15 DPA. C-type granules also decreased in response to 15 DPA in all varieties, except HD-2329. The starch from wheat exposed to WS at 15 DPA showed lower amylose content, lipids content and pasting temperature, and higher peak viscosity, final viscosity and setback. DSC analysis of starches showed two endotherms (associated with the melting of crystallites and amylose–lipid [AML] complexes) during heating, and an exotherm (associated with reforming of AML) during cooling. Transition temperatures ( T o, T p and T c) of AML dissociation and association were lower for starch from wheat exposed to WS, the effect being more at 15 DPA. The changes in pasting and thermal properties of starch caused by WS were observed to be related to lipids, amylose content and distribution of granules. The effect of WS on accumulation of different dimethyl formamide-soluble and insoluble proteins was significant and variety dependent.

Multivariate analysis of 2‐DE protein patterns – Practical approaches

Practical approaches to the use of multivariate data analysis of 2-DE protein patterns are demonstrated by three independent strategies for the image analysis and the multivariate analysis on the same set of 2-DE data. Four wheat varieties were selected on the basis of their baking quality. Two of the varieties were of strong baking quality and hard wheat kernel and two were of weak baking quality and soft kernel. Gliadins at different stages of grain development were analyzed by the application of multivariate data analysis on images of 2-DEs. Patterns related to the wheat varieties, harvest times and quality were detected on images of 2-DE protein patterns for all the three strategies. The use of the multivariate methods was evaluated in the alignment and matching procedures of 2-DE gels. All the three strategies were able to discriminate the samples according to quality, harvest time and variety, although different subsets of protein spots were selected. The explorative approach of using multivariate data analysis and variable selection in the analyses of 2-DEs seems to be promising as a fast, reliable and convenient way of screening and transforming many gel images into spot quantities.

Chlorogenic acid synthesis in coffee: An analysis of CGA content and real-time RT-PCR expression of HCT, HQT, C3H1, and CCoAOMT1 genes during grain development in C. canephora

The mature coffee grain contains a high level of chlorogenic acids (CGA). We have quantified the main caffeoylquinic acids (CQA) and dicaffeoylquinic acids (diCQA) in Coffea canephora (robusta) grain during late development. This analysis indicates the CQA levels remain relatively steady during the final stages of grain development, but the levels of diCQA fall significantly. Analysis of quinic acid, a key CGA precursor in coffee, shows it is present at a high level in the early grain, but then drops to a low level as development progresses. To better understand coffee CGA synthesis, and to learn why diCQA and quinic acid levels fall late in grain development, we have cloned cDNA encoding four key enzymes for CGA synthesis in coffee; HCT, HQT, C3H1 and CCoAOMT1. The characterization of recombinant HCT, HQT and CCoAOMT1 proteins is also described. Quantitative real-time RT-PCR data is presented for different stages of grain and pericarp development, as well as several other C. canephora tissues. Elevated HCT and CCoAOMT1 expression in branch tissues strongly suggests the products of these genes are associated with increased lignin synthesis, while higher HQT expression appears to be more closely correlated with CGA accumulation. The data presented forms an important base for designing new experiments aimed at improving our understanding of CGA synthesis in coffee and other plants, and could facilitate the development of new strategies to increase the CGA content of plant foods.

EFFECTS OF RICE PANICLE AGE ON QUANTITATIVE AND QUALITATIVE INJURY BY THE RICE STINK BUG (HEMIPTERA: PENTATOMIDAE)

Abstract Greenhouse experiments were conducted to evaluate the effects of panicle age on quantitative and qualitative injury caused by rice stink bug, Oebalus pugnax pugnax (Fab.), infestations on rice, Oryza sativa L. The effects were measured at two infestation levels (one and two bugs per panicle) and compared with an undamaged control. Percentage of empty grains and average weight of filled grains (quantitative injury) and percentage of pecky rice (qualitative injury) were evaluated at grain maturity. Regardless of infestation level, insect feeding during anthesis and the early milk stage of grain development (first 8 d after anthesis) caused substantially higher numbers of empty grains than feeding during later grain development and the control. Average grain weights were lower in infestations during anthesis and milk stage and higher in infestations during later grain development and the control. Pecky rice was significantly higher during late milk and soft dough stages, 9-16 d after anthesis, compa...

Characterization Using Raman Microspectroscopy of Arabinoxylans in the Walls of Different Cell Types during the Development of Wheat Endosperm

The time course and pattern of arabinoxylan deposition in the wheat (Triticum aestivum) endosperm during grain development were studied using Raman spectroscopy. The presence of arabinoxylans (AX) is detected at the beginning of grain filling. At this stage, AX appear more substituted than at the later stages. Feruloylation of AX increases during the grain-filling stage, especially in the case of the aleurone layer. Whatever the stage of grain development, four populations of cells could be defined according to Raman arabinoxylan signatures. In the walls of the aleurone cells, AX appeared to be little substituted and highly esterified with phenolic acids. In the walls of prismatic cells, AX were found to be highly substituted and poorly esterified. Apart from aleurone and prismatic cells, the substitution degree of AX in endosperm was in the same range. Cells in the crease region were distinguished from cells in the starchy endosperm by their lower amount of esterified phenolic compounds.

Field studies on the regulation of abscisic acid content and germinability during grain development of barley: molecular and chemical analysis of pre-harvest sprouting

To investigate whether the regulation of abscisic acid (ABA) content was related to germinability during grain development, two cDNAs for 9-cis-epoxycarotenoid dioxygenase (HvNCED1 and HvNCED2) and one cDNA for ABA 8'-hydroxylase (HvCYP707A1), which are enzymes thought to catalyse key regulatory steps in ABA biosynthesis and catabolism, respectively, were cloned from barley (Hordeum vulgare L.). Expression and ABA-quantification analysis in embryo revealed that HvNCED2 is responsible for a significant increase in ABA levels during the early to middle stages of grain development, and HvCYP707A1 is responsible for a rapid decrease in ABA level thereafter. The change in the embryonic ABA content of imbibing grains following dormancy release is likely to reflect changes in the expression patterns of HvNCEDs and HvCYP707A1. A major change between dormant and after-ripened grains occurred in HvCYP707A1; the increased expression of HvCYP707A1 in response to imbibition, followed by a rapid ABA decrease and a high germination percentage, was observed in the after-ripened grains, but not in the dormant grains. Under field conditions, HvNCED2 showed the same expression level and pattern during grain development in 2002, 2003, and 2004, indicating that HvNCED2 expression is regulated in a growth-dependent manner in the grains. By contrast, HvNCED1 and HvCYP707A1 showed a different expression pattern in each year, indicating that the expression of these genes is affected by environmental conditions during grain development. The varied expression levels of these genes during grain development and imbibition, which would have effects on the activity of ABA biosynthesis and catabolism, might be reflected, in part, in the germinability in field-grown barley.

Deposition of Cell Wall Polysaccharides in Wheat Endosperm during Grain Development: Fourier Transform-Infrared Microspectroscopy Study

The time course and pattern deposition of the cell wall polysaccharides in the starchy endosperm of wheat (Triticum aestivum cv. Recital) during grain development was studied using Fourier transform infrared microspectroscopy (micro-FTIR). Three stages of grain development identified as key stages for cell wall construction were retained as follows: the end cellularization, the beginning of cell differentiation, and the beginning of maturation. Micro-FTIR revealed that beta-(1-->3),(1-->4) glucans and arabinoglactan proteins are the main cell wall components of endosperm at the end of the cellularization stage, whereas arabinoxylans (AX) appeared only at the cell differentiation stage. Past the differentiation stage, FTIR spectra were dominated by AX features. Cell walls at the beginning of cell differentiation and at endosperm maturation could be distinguished by spectral features that were ascribed to AX substitution. AX appeared more substituted at the beginning of cell differentiation. Moreover, a difference in the degree of AX substitution was found between peripheral and central parts of the grain at the cell differentiation stage; AX in central cells was less substituted. Thus, dramatic changes in endosperm cell wall composition were detected during wheat grain development with respect to both the relative occurrence of individual constituents and the fine structure of the AX.

Gene expression of the biosynthetic enzymes and biosynthesis of starch during Rice Grain development

Amylose and amylopectin are determinants of the physicochemical properties for starch and grain quality in rice. Their biosynthesis is catalyzed by the interplay of ADP-glucose pyrophosphorylase (AGPase), granule-bound starch synthase (GBSS), soluble starch synthase (SSS), a starch branching enzyme (SBE), and a starch debranching enzyme (SDE). In this study, the genes for these enzymes were highly expressed 7 to 28 days after flowering during grain development, and their expression closely matched increases in both starch content and grain weight Among all the tested cultivars, amylose contents in the rice grains remained essentially constant throughout their development The AGPase gene was highly expressed in the high-yield cultivars of both glutinous and non-glutinous rice. The SSS gene was actively expressed when mature GBSS mRNA decreased. Genes responsible for amylopectin biosynthesis were simultaneously expressed in the late stage of grain development. We have now demonstrated that the expression patterns of starch biosynthetic genes differ between glutinous and non-glutinous rice, and between Tongil (a Japonica/ Indica hybrid) and Japonica types.

Developmental changes in the metabolic protein profiles of wheat endosperm

A combined two-dimensional gel electrophoresis-mass spectrometry approach was utilized to identify over 250 proteins of wheat (Triticum aestivum L., cv. Butte 86) starchy endosperm that participate in 13 biochemical processes: ATP interconversion reactions, carbohydrate metabolism, cell division, cytoskeleton, lipid metabolism, nitrogen metabolism, protein synthesis/assembly, protein turnover, signal transduction, protein storage, stress/defense, transcription/translation, and transport. Endosperm protein populations were compared at early (10 days post-anthesis, dpa) and late (36 dpa) stages of grain development. Analysis of protein number and spot volume revealed that carbohydrate metabolism, transcription/translation, and protein synthesis/assembly were the principal endosperm functions at 10 dpa followed by nitrogen metabolism, protein turnover, cytoskeleton, cell division, signal transduction, and lipid metabolism. Carbohydrate metabolism and protein synthesis/assembly were also major functions at 36 dpa, but stress/defense and storage were predominant. The results provide insight into biochemical events taking place during wheat grain development and highlight the value of proteomics in characterizing complex biochemical processes. Further, the proteome maps will facilitate future studies addressing the effects of genetic and environmental factors on the development and quality of wheat grain.

Early prediction of wheat quality: analysis during grain development using mass spectrometry and multivariate data analysis

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and multivariate data analysis have been used for the determination of wheat quality at different stages of grain development. Wheat varieties with one of two different end-use qualities (i.e. suitable or not suitable for bread-making purposes) were investigated. The samples were collected from grains from 15 until 45 days post-anthesis (dpa). Gluten proteins from wheat grains were extracted and subsequently analysed by mass spectrometry. Discrimination partial least-squares regression and soft independent modelling of class analogy were used to determine the quality of new and unknown wheat samples. With these methods, we were able to predict correctly the end-use qualities at every stage investigated. This new fast technique, based on the rapidity of mass spectrometry combined with the objectivity of multivariate data analysis, offers a method that can replace the traditional rather time-consuming ones such as gel electrophoresis. This study focused on the determination of wheat quality at 15 dpa, when the grain is due for harvest 1 month later.

Genetic analysis of methionine content in indica-japonica hybrid rice (Oryza sativa L.) at different grain developmental stages

Genetics of methionine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 F1 hybrids derived from crossing 7 male-sterile indica rice cultivars with 5 restorer japonica rice cultivars. Two genetic models and their corresponding statistical methods for quantitative traits of triploid endosperm in cereal crops were used for the analysis. One is the unconditional model, which refers to the analysis of cumulative measurements along the developmental stages, while another is the conditional model, which relates to analysis throughout the developmental stages. Results showed that methionine content of indica-japonica hybrid rice was controlled by expression of triploid endosperm nuclear genes, cytoplasm genes, diploid maternal plant nuclear genes, and their genotype-environment interaction effects. Dominant effects were important at the first three developmental stages, while additive effects were important at the next two stages of grain development under both unconditional and conditional analyses. With regard to the components of heritability, maternal and cytoplasm general heritabilities and their environmental interaction heritabilities were important. It was suggested that enhancing methionine content could be more efficient when selection is based on maternal plants in early breeding generations.