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Endosperm
Terms modified by Endosperm Selected AbstractsMODULARITY OF THE ANGIOSPERM FEMALE GAMETOPHYTE AND ITS BEARING ON THE EARLY EVOLUTION OF ENDOSPERM IN FLOWERING PLANTSEVOLUTION, Issue 2 2003William E. Friedman Abstract The monosporic seven-celled/eight-nucleate Polygonumtype female gametophyte has long served as a focal point for discussion of the origin and subsequent evolution of the angiosperm female gametophyte. In Polygonumtype female gametophytes, two haploid female nuclei are incorporated into the central cell, and fusion of a sperm cell with the binucleate central cell produces a triploid endosperm with a complement of two maternal and one paternal genomes, characteristic of most angiosperms. We document the development of a four-celled/four-nucleate female gametophyte in Nuphar polysepala (Engelm.) and infer its presence in many other ancient lineages of angiosperms. The central cell of the female gametophyte in these taxa contains only one haploid nucleus; thus endosperm is diploid and has a ratio of one maternal to one paternal genome. Based on comparisons among flowering plants, we conclude that the angiosperm female gametophyte is constructed of modular developmental subunits. Each module is characterized by a common developmental pattern: (1) positioning of a single nucleus within a cytoplasmic domain (pole) of the female gametophyte; (2) two free-nuclear mitoses to yield four nuclei within that domain; and (3) partitioning of three uninucleate cells adjacent to the pole such that the fourth nucleus is confined to the central region of the female gametophyte (central cell). Within the basal angiosperm lineages Nymphaeales and Illiciales, female gametophytes are characterized by a single developmental module that produces a four-celled/four-nucleate structure with a haploid uninucleate central cell. A second pattern, typical of Amborella and the overwhelming majority of eumagnoliids, monocots, and eudicots, involves the early establishment of two developmental modules that produce a seven-celled/eight-nucleate female gametophyte with two haploid nuclei in the central cell. Comparative analysis of onto-genetic sequences suggests that the seven-celled female gametophyte (two modules) evolved by duplication and ectopic expression of an ancestral Nuphar- like developmental module within the chalazal domain of the female gametophyte. These analyses indicate that the first angiosperm female gametophytes were composed of a single developmental module, which upon double fertilization yielded a diploid endosperm. Early in angiosperm history this basic module was duplicated, and resulted in a seven-celled/eight-nucleate female gametophyte, which yielded a triploid endosperm with the characteristic 2:1 maternal to paternal genome ratio. [source] Removal of high-abundance proteins for nuclear subproteome studies in rice (Oryza sativa) endospermELECTROPHORESIS, Issue 3 2008Guosheng Li Abstract Endosperm is a highly specialized storage organ with three sets of genomes. It is one of the most economically important organs in plants. Endosperm development involves parental imprinting and endoreduplication. A thorough study of the endosperm proteome, particularly the nuclear proteome, may provide critical insight into the regulation of seed development. Unfortunately, endosperm is extremely rich in starch grains and protein bodies of different sizes, making proteome studies on nonstorage proteins, particularly the low-abundance proteins, very challenging. Here we have developed a chromatographic method to remove large starch grains and an electrophoresis method to recover low-abundance proteins, respectively. Using these methods, we have identified 468 proteins from the nuclear enriched fraction of rice endosperm, including transcription factors, histone modification proteins, kinetochore proteins, centromere/microtubule binding proteins, and transposon proteins. Among the 468 proteins, 208 (44%) are hypothetical proteins, indicating that the endosperm proteome is poorly explored. In addition, analyses of the MS/MS data using BioWorks 3.1 have identified 59 putative acetylated proteins and 40 putative methylated proteins. Our studies have developed a method to remove starch grains and recover low-abundance proteins, respectively. The methods should be applicable to other organisms. [source] MODULARITY OF THE ANGIOSPERM FEMALE GAMETOPHYTE AND ITS BEARING ON THE EARLY EVOLUTION OF ENDOSPERM IN FLOWERING PLANTSEVOLUTION, Issue 2 2003William E. Friedman Abstract The monosporic seven-celled/eight-nucleate Polygonumtype female gametophyte has long served as a focal point for discussion of the origin and subsequent evolution of the angiosperm female gametophyte. In Polygonumtype female gametophytes, two haploid female nuclei are incorporated into the central cell, and fusion of a sperm cell with the binucleate central cell produces a triploid endosperm with a complement of two maternal and one paternal genomes, characteristic of most angiosperms. We document the development of a four-celled/four-nucleate female gametophyte in Nuphar polysepala (Engelm.) and infer its presence in many other ancient lineages of angiosperms. The central cell of the female gametophyte in these taxa contains only one haploid nucleus; thus endosperm is diploid and has a ratio of one maternal to one paternal genome. Based on comparisons among flowering plants, we conclude that the angiosperm female gametophyte is constructed of modular developmental subunits. Each module is characterized by a common developmental pattern: (1) positioning of a single nucleus within a cytoplasmic domain (pole) of the female gametophyte; (2) two free-nuclear mitoses to yield four nuclei within that domain; and (3) partitioning of three uninucleate cells adjacent to the pole such that the fourth nucleus is confined to the central region of the female gametophyte (central cell). Within the basal angiosperm lineages Nymphaeales and Illiciales, female gametophytes are characterized by a single developmental module that produces a four-celled/four-nucleate structure with a haploid uninucleate central cell. A second pattern, typical of Amborella and the overwhelming majority of eumagnoliids, monocots, and eudicots, involves the early establishment of two developmental modules that produce a seven-celled/eight-nucleate female gametophyte with two haploid nuclei in the central cell. Comparative analysis of onto-genetic sequences suggests that the seven-celled female gametophyte (two modules) evolved by duplication and ectopic expression of an ancestral Nuphar- like developmental module within the chalazal domain of the female gametophyte. These analyses indicate that the first angiosperm female gametophytes were composed of a single developmental module, which upon double fertilization yielded a diploid endosperm. Early in angiosperm history this basic module was duplicated, and resulted in a seven-celled/eight-nucleate female gametophyte, which yielded a triploid endosperm with the characteristic 2:1 maternal to paternal genome ratio. [source] Cell wall hemicelluloses as mobile carbon stores in non-reproductive plant tissuesFUNCTIONAL ECOLOGY, Issue 5 2007G. HOCH Summary 1As essential compounds of plant cell walls, hemicelluloses account for about a quarter of all plant biomass worldwide. 2In seed cotyledons and endosperm of species from several plant families, hemicelluloses are used as mobile carbon reserves. Whether cell wall hemicelluloses of non-reproductive plant tissue are multifunctional molecules, which can also serve as carbon sources during periods of enhanced carbon demand, is still equivocal. 3This review summarizes the current understanding of a possible reserve function of hemicelluloses. Although several descriptive and experimental studies suggested at least partial mobility of cell wall polysaccharides in mature, non-reproductive plant tissues, there is still a need for a broad-scale, ecophysiological exploration of the actual nature of hemicelluloses beyond their structural function. 4The chemical heterogeneity of hemicelluloses may be the major problem for precise quantitative analyses on a large, comparative scale. 5Because of the abundant distribution of hemicelluloses in plants, the existence of a significant mobile carbohydrate pool in cell walls of non-reproductive organs would shed rather new light on plant carbon relations in a source-sink context. 6Consequently, a reserve function of hemicelluloses questions the conventional division of cell compounds into structural (i.e. immobile) and non-structural (i.e. mobile) compounds. [source] SEASONAL VARIATIONS IN FATTY ACID COMPOSITION OF OIL IN DEVELOPING COCONUTJOURNAL OF FOOD QUALITY, Issue 2 2009S. NARESH KUMAR ABSTRACT Studies on seasonal variation in oil and fatty acid profile of developing solid endosperm of two cultivars, West Coast Tall (WCT) and Chowghat Orange Dwarf (COD), and their hybrids indicated that oil percentage increased from 30% in 6-month-old nuts to 63% in matured nuts (12 months old). Nuts sampled during July from different levels of maturity had high oil percentage and followed by those sampled during April, October and January. During nut development to maturity, the percentages and contents of medium and long chain saturated fatty acids increased except that of palmitic and myristic acids. Concentration of long chain unsaturated fatty acids (LCUFAs) in developing coconut kernel were high at 5 and 6 months after fertilization and then decreased toward maturity. The LCUFAs were high in nuts developing during October; consequently, saturated to unsaturated fatty acid ratios were low during October. Results indicated that nuts matured during October had better nutritional quality for human consumption and those matured during January are more suitable for industrial purpose due to higher medium chain fatty acid concentrations. PRACTICAL APPLICATIONS Coconut is consumed either as the tender nut (5,6 months after fertilization) or as the kernel from mature nut (12 months after fertilization). Recent technologies of making snowball tender nut use the nuts aged 7,8 months old. Kernel also is consumed in this product. Apart from this, the coconut is being increasingly used for making different kernel-based value-added products. This information is useful, as the value-added products are being developed using different maturities of coconut. Hence, it is of paramount importance that the fatty acid profile of coconut kernel is known in detail for assessing the safety of food consumption from the human health point of view. Apart from this, information on the seasonal variation in fatty acid profile of developing endosperm gives an integrated knowledge so as to optimize the usage of coconut kernel for both human consumption and industrial exploitation. [source] The Green Oat Story: Possible Mechanisms of Green Color Formation in Oat Products during CookingJOURNAL OF FOOD SCIENCE, Issue 6 2009D.C. Doehlert ABSTRACT:, Consumers occasionally report greenish colors generated in their oat products when cooking in tap water. Here we have investigated pH and ferrous (Fe2+) ion as possible mechanisms for this color change. Steel-cut oat groats can turn brown-green color when cooked in alkaline conditions (pHs 9 to 12). Extraction of this color with methanol, and high-pressure liquid chromatography indicated a direct association of this color with the phenolic acid or avenanthramide content of the oat. The presence of 50 mM NaHCO3 in water will cause oat/water mixtures to turn alkaline when cooked as CO2 is driven off, generating OH, ion. Although tap water rarely, if ever, contains so much bicarbonate, bicarbonate is used as a leavening agent in baking applications. Industrial interests using baking soda or alkaline conditions during oat processing should be aware of possible off color generation. We have also found that as little as 10 ppm Fe2+ will turn oat products gray-green when cooked. The aleurone stained darker than the starchy endosperm. Other divalent cations, such as Ca2+ or Mg2+ had no effect on cooked oat color. As much as 50 ppm Fe2+ may be found in freshly pumped well water, but Fe2+ reacts quickly with oxygen and precipitates as Fe(OH)3. Thus, some freshly pumped well water may turn oats green when cooked, but if the water is left under atmospheric conditions for several hours, no discoloration will appear in the cooked oats. [source] Opalescence in Australian-grown Pecan Kernels: Occurrence and CausesJOURNAL OF FOOD SCIENCE, Issue 8 2002L.T. Wakeling ABSTRACT: Opalescence is an unattractive browning of the interior of the pecan kernel compared to the white interior of normal kernels. The discoloration is due to the presence of free oil, resulting from decompartmentalization in the endosperm of opalescent pecans. Using a subjective scoring system, approximately 70% of Australian-grown pecan kernels tested were found to exhibit opalescence to some degree. Evaluation of kernels for opalescence during the harvesting-processing chain showed that opalescence first becomes evident in kernels after mechanical cracking. Opalescent kernels were found to have lower levels of calcium and higher amounts of oil compared to nonopalescent kernels. Differential scanning calorimetry showed that kernels do not freeze at -18 °C. [source] Starch Synthesis and Programmed Cell Death during Endosperm Development in Triticale (×Triticosecale Wittmack)JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 7 2010Chun-Yan Li Triticale (×Triticosecale Wittmack) grains synthesize and accumulate starch as their main energy source. Starch accumulation rate and synthesis activities of ADP-glucose pyrophosphorylase, soluble starch synthases, granule-bound starch synthase and starch-branching enzyme showed similar pattern of unimodal curves during endosperm development. There was no significant difference in activity of the starch granule-bound protein isolated from total and separated starch granules at different developmental stages after anthesis in triticale. Evans Blue staining and analysis of DNA fragmentation indicated that cells of triticale endosperm undergo programmed cell death during its development. Dead cells within the endosperm were detected at 6 d post anthesis (DPA), and evidence of DNA fragmentation was first observed at 21 DPA. The period between initial detection of PCD to its rapid increase overlapped with the key stages of rapid starch accumulation during endosperm development. Cell death occurred stochastically throughout the whole endosperm, meanwhile, the activities of starch biosynthetic enzymes and the starch accumulation rate decreased in the late stages of grain filling. These results suggested that the timing and progression of PCD in triticale endosperm may interfere with starch synthesis and accumulation. [source] Cell-wall Invertases from Rice are Differentially Expressed in Caryopsis during the Grain Filling StageJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 4 2008Yong-Qin Wang Abstract Cell-wall invertase plays an important role in sucrose partitioning between source and sink organs in higher plants. To investigate the role of cell-wall invertases for seed development in rice (Oryza sativa L.), cDNAs of three putative cell-wall invertase genes OsCIN1, OsCIN2 and OsCIN3 were isolated. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed different expression patterns of the three genes in various rice tissues/organs. In developing caryopses, they exhibited similar temporal expression patterns, expressed highly at the early and middle grain filling stages and gradually declined to low levels afterward. However, the spatial expression patterns of them were very different, with OsCIN1 primarily expressed in the caryopsis coat, OsCIN2 in embryo and endosperm, and OsCIN3 in embryo. Further RNA in situ hybridization analysis revealed that a strong signal of OsCIN2 mRNA was detected in the vascular parenchyma surrounding the xylem of the chalazal vein and the aleurone layer, whereas OsCIN3 transcript was strongly detected in the vascular parenchyma surrounding the phloem of the chalazal vein, cross-cells, the aleurone layer and the nucellar tissue. These data indicate that the three cell-wall invertase genes play complementary/synergetic roles in assimilate unloading during the grain filling stage. In addition, the cell type-specific expression patterns of OsCIN3 in source leaf blades and anthers were also investigated, and its corresponding physiological roles were discussed. [source] Genetic Analysis and Mapping of the Dominant Dwarfing Gene D-53 in RiceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 4 2006Li-Rong Wei Abstract The dwarfing gene D-53 is one of a few dominant genes for dwarfing in rice (Oryza sativa L.). In the present study, our genetic analysis confirmed that mutant characteristics including dwarfing, profuse tillering, thin stems and small panicles are all controlled by the dominant D-53 gene. We measured the length of each internode of KL908, a D-53- carrying line, and classified the dwarfism of KL908 into the dn-type. In addition, we measured elongation of the second sheath and ,-amylase activity in the endosperm, and we characterized KL908 as a dwarf mutant that was neither gibberellic acid-deficient nor gibberellic acid-insensitive. Using a large F2 population obtained by crossing KL908 with a wild-type variety, NJ6, the D-53 gene was mapped to the terminal region of the short arm of chromosome 11, with one simple sequence repeat marker, Ds3, co-segregating, and the other, K81114, located 0.6 cM away. (Managing editor: Li-Hui Zhao) [source] Distribution of fatty acids in edible organs and seed fractions of borage (Borago officinalis L.)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2008Mercedes del Río-Celestino Abstract BACKGROUND: Borage (Borago officinalis L.) is currently used as a vegetable in the north of Spain. The edible parts of the plant are the petioles, leaves and stems. The objective of this study was to determine the oil and fatty acids content in the edible tissues (leaves, petioles and stems) and seed fractions (endosperm + cotyledon, seed coat and elaiosome) of white- and blue-flowered borage accessions. RESULTS: Leaves showed higher mean values of oil content (2.7%) than petioles and stems (1.1% and 1.4%, respectively) in both, blue- and white-flowered material. The most abundant fatty acids in leaves were palmitic, linoleic, ,-linolenic and stearidonic acids (about 75% of the total fatty acids), while in petioles and stems myristic and linoleic acids were most abundant (about 60% of the total fatty acids). Palmitic, oleic, linoleic and ,-linolenic (GLA) acids were the major fatty acids of seed coat and endosperm + cotyledon in borage seeds (85% of the total fatty acids), while palmitic, stearic, oleic and linoleic acids were the most abundant fatty acids of elaisome in borage seeds (80% of the total fatty acids). CONCLUSION: This paper shows that green parts of borage contain substantial amounts of omega-3 and omega-6 fatty acids, which are essential fatty acids for animal and human nutrition. Thus, borage could be a ,power food' of the future because of its content of unsaturated fatty acids, particularly the essential fatty acids, which have great potential to prevent cardiovascular disease, cancer and infectious diseases. Copyright © 2007 Society of Chemical Industry [source] Optimising the determination of maize endosperm vitreousness by a rapid non-destructive image analysis technique,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2004Corinda Erasmus Abstract A rapid non-destructive image analysis technique was developed and optimised for the determination of maize endosperm vitreousness without the need for sample preparation. Maize kernel translucency measurements were optimised for a light system consisting of positioning whole kernels on top of round illuminated areas smaller than the projected areas of the kernels, allowing light to shine through the kernels. A correction factor to allow for constant illumination of kernels was developed to adjust for kernel size variation in relation to constant light area. The intensity of translucency in maize is linearly correlated to the percentage of kernel illumination (r = 0.99, p < 0.001). Significant correlations were found between corrected translucency values and endosperm yields determined by hand dissection. These were: translucency as a percentage of the whole kernel and vitreous endosperm (mass%), r = 0.77; translucency as a percentage of the whole kernel and opaque endosperm (mass%), (r = ,0.72); translucency as a percentage of endosperm and vitreous endosperm (mass%), r = 0.81; and translucency as a percentage of endosperm and opaque endosperm (mass%), r = ,0.77; with n = 245 in all instances. Translucency varied by 29.5% between the lowest and highest values, and vitreous endosperm (mass%) varied by 16.8% between the lowest and highest values. Correlations increased significantly after corrections for kernel thickness. A thickness increase of 1 mm in the maize will cause a decrease of 21.86% in translucency and vice versa. The method allows for large samples (at least 49 kernels min,1) to be analysed for individual vitreous and opaque endosperm contents with no interferences with kernel structure. With further development of suitable automated sampling techniques, it could become a suitable potential method for in-line quantification of maize endosperm contents. Copyright © 2004 Society of Chemical Industry [source] Speciation and distribution of arsenic and localization of nutrients in rice grainsNEW PHYTOLOGIST, Issue 1 2009E. Lombi Summary ,,Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. ,,Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC),inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (µ-XANES, µ-X-ray fluorescence (µ-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. ,,The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III),thiol complexes. ,,The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains. [source] A model of triploid endosperm evolution driven by parent-offspring conflictOIKOS, Issue 3 2001Roger Härdling The parental investment in angiosperms comprises the endosperm, a nutrient reserve that is used during seed development. The endosperm contains genes from both parents. The most common endosperm form is the 3n Polygonum -type with more maternal genetic influence than paternal, i.e. with two maternal nuclei and one paternal nucleus. The evolutionary original state is thought to be a diploid endosperm with equal influence of the parents. We focus on the evolution of the triploid endosperm and show that a gene for triploid endosperm would have an initial advantage in a population of diploid endosperm type plants, and increase to fixation. We assume that endosperm amount is controlled by endosperm genes. Then a gene causing triploid endosperm will increase the influence of the mother plant on parental investment. The production of endosperm with two copies of the maternal genes will modify the inheritance of endosperm amount and cause an increased production of seeds. [source] Development of insect-resistant transgenic rice with Cry1C*-free endospermPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 9 2009Rongjian Ye Abstract BACKGROUND: Yellow stem borer (Tryporyza incertulas Walker), striped stem borer (Chilo suppressalis Walker) and leaf folder (Cnaphalocrocis medinalis Guenec) are three lepidopteran pests that cause severe damage to rice in many areas of the world. In this study, novel insect-resistant transgenic rice was developed in which Bt protein expression was nearly absent in the endosperm. The resistant gene, cry1C*, driven by the rice rbcS promoter (small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase), was introduced into Zhonghua 11 (Oryza sativa L. ssp. japonica) by Agrobacterium -mediated transformation. RESULTS: A total of 83 independent transformants were obtained, 19 of which were characterised as single-copy foreign gene insertion. After preliminary screening of the T1 families of these 19 transformants in the field, six highly insect-resistant homozygous lines were selected. These six homozygous transgenic lines were field tested for resistance to leaf folders and stem borers, and for their agronomic performance. The Cry1C* protein levels in leaves and endosperm were measured by ELISA. Subsequently, the elite transgenic line RJ5 was selected; this line not only possessed high resistance to leaf folders and stem borers, normal agronomic performance, but also Cry1C* expression was only 2.6 ng g,1 in the endosperm. CONCLUSION: These results indicated that RJ5 has the potential for widespread utility in rice production. Copyright © 2009 Society of Chemical Industry [source] Activity and concentration of non-proteolyzed phosphoenolpyruvate carboxykinase in the endosperm of germinating castor oil seeds: effects of anoxia on its activityPHYSIOLOGIA PLANTARUM, Issue 4 2007Mariana Martín Phosphoenolpyruvate carboxykinase (PEPCK; EC 4.1.1.49) catalyses the reversible decarboxylation of oxaloacetate to phosphoenolpyruvate in the gluconeogenic production of sugars from storage lipids in germinating oil seeds. The enzyme is quite susceptible to limited proteolysis during extraction. Immunoblotting was used to diagnose unwanted in vitro proteolytic activity against PEPCK from germinating castor oil seeds (COS) by following the disappearance of its native 74-kDa subunit and concomitant appearance of a truncated 64-kDa polypeptide. Alkaline pH and the inclusion of thiol protease inhibitors effectively prevented COS PEPCK proteolysis during incubation of clarified COS extracts at 4°C. The carboxylating and decarboxylating activities and concentration of non-proteolyzed COS PEPCK were investigated during germination. This is the first report in which both activities catalyzed by PEPCK were measured in vitro during a whole developmental process. Carboxylating activity and the level of immunoreactive 74-kDa PEPCK polypeptides rapidly increased in parallel to maximal values by day 5 and then significantly declined over the subsequent 2 days. In contrast, decarboxylating PEPCK activity was much higher over the 7 days of growth examined. In addition, the effect on PEPCK activity while changing the endosperm from aerobic (when gluconeogenesis predominates in the tissue) to anaerobic conditions (where the tissue becomes glycolytic) was studied. While PEPCK decarboxylating activity remained almost constant, carboxylating activity declined to undetectable levels in response to anaerobiosis. These and the developmental profile results suggest that COS PEPCK may be subject to a mechanism of post-translation control that selectively inhibits the carboxylating, but not the decarboxylating activity. [source] Bifunctional indole-3-acetyl transferase catalyses synthesis and hydrolysis of indole-3-acetyl- myo -inositol in immature endosperm of Zea maysPHYSIOLOGIA PLANTARUM, Issue 2 2003Stanislaw Kowalczyk 1- O -(indole-3-acetyl)- , - d -glucose: myo -inositol indoleacetyl transferase (IA- myo -inositol synthase) is an important enzyme in IAA metabolism. This enzyme catalyses the transfer of the indole acetyl (IA) moiety from 1- O -(indole-3-acetyl)- , - d -glucose to myo -inositol to form IA- myo- inositol and glucose. IA- myo -inositol synthase was purified to an electrophoretically homogenous state from maize liquid endosperm by fractionation with ammonium sulphate, anion-exchange, adsorption on hydroxylapatite, affinity chromatography on ConA-Sepharose, preparative PAGE and isoelectric focusing. We thus obtained two enzyme preparations which differ in their Rf on 8% polyacrylamide gel. The preparation of Rf 0.36 contained a single 56.4 kDa polypeptide, whereas the preparation of Rf 0.39 consisted of two polypeptides of 56.4 and 53.5 kDa. Both purified preparations of IAInos synthase also exhibited the activity of an IAInos hydrolase, showing that the dual activity was associated with a single protein. Results of gel filtration and analytical SDS-PAGE suggest that the native enzyme exists as both a monomeric (65 kDa) and homo- or heterodimeric form (110,130 kDa). Analysis of peptide maps and amino acid sequences of two 21 amino-acid peptides showed that polypeptides of 56.4 and 53.5 kDa have the same primary structure and that the 3 kDa difference in molecular mass is probably caused by different glycosylation levels. Comparison of this partial and internal amino acid sequence with sequences of other plant acyltransferases indicated similarity to several proteins which belonged to the serine carboxypeptidase-like (SCPL) acyltransferase family. [source] Immunolocalization of the PmSUC1 Sucrose Transporter in Plantago major Flowers and Reporter-Gene Analyses of the PmSUC1 Promoter Suggest a Role in Sucrose Release from the Inner IntegumentPLANT BIOLOGY, Issue 3 2007C. Lauterbach Abstract: This paper presents a detailed analysis of the PmSUC1 gene from Plantago major, of its promoter activity in Arabidopsis, and of the tissue specific localization of the encoded protein in Plantago. PmSUC1 promoter activity was detected in the innermost layer of the inner integument (the endothel) of Arabidopsis plants expressing the gene of the green fluorescent protein (GFP) under the control of the PmSUC1 promoter. This promoter activity was confirmed with a PmSUC1-specific antiserum that identified the PmSUC1 protein in the endothel of Plantago and of Arabidopsis plants expressing the PmSUC1 gene under the control of its own promoter. PmSUC1 promoter activity and PmSUC1 protein were also detected in pollen grains during maturation inside the anthers and in pollen tubes during and after germination. These results demonstrate that PmSUC1 is involved in sucrose partitioning to the young embryo and to the developing pollen and growing pollen tube. In the innermost cell layer of the inner integument, a tissue that delivers nutrients to the endosperm and the embryo, PmSUC1 may catalyze the release of sucrose into the apoplast. [source] Developmental Anatomy and Morphology of the Ovule and Seed of Heliconia (Heliconiaceae, Zingiberales)PLANT BIOLOGY, Issue 1 2006D. G. Simăo Abstract: The developmental anatomy and morphology of the ovule and seed in several species of Heliconia were investigated as part of an embryological study of the Heliconiaceae and to provide a better understanding of their relationships with the other families of the Zingiberales. Heliconia species have an ovule primordium with an outer integument of both dermal and subdermal origin. The archesporial cell is divided into a megasporocyte and a single parietal cell, which in turn are divided only anticlinally to form a single parietal layer, disintegrating later during gametogenesis. The embryo sac was fully developed prior to anthesis. In the developing seed, the endosperm was nuclear, with wall formation in the globular stage; a nucellar pad was observed during embryo development, but later became compressed. The ripe fruit contained seeds enveloped by a lignified endocarp that formed the pyrenes, with each pyrene having an operculum at the basal end; the embryo was considered to be differentiated. Most of these characteristics are shared with other Zingiberales, although the derivation of the operculum from the funicle and the formation of the main mechanical layer by the endocarp are unique to the Heliconiaceae. [source] Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endospermPLANT BIOTECHNOLOGY JOURNAL, Issue 3 2010Jesper Harholt Summary Endo-xylanase (from Bacillus subtilis) or ferulic acid esterase (from Aspergillus niger) were expressed in wheat under the control of the endosperm-specific 1DX5 glutenin promoter. Constructs both with and without the endoplasmic reticulum retention signal (Lys-Asp-Glu-Leu) KDEL were used. Transgenic plants were recovered in all four cases but no qualitative differences could be observed whether KDEL was added or not. Endo-xylanase activity in transgenic grains was increased between two and threefold relative to wild type. The grains were shrivelled and had a 25%,33% decrease in mass. Extensive analysis of the cell walls showed a 10%,15% increase in arabinose to xylose ratio, a 50% increase in the proportion of water-extractable arabinoxylan, and a shift in the MW of the water-extractable arabinoxylan from being mainly larger than 85 kD to being between 2 and 85 kD. Ferulic acid esterase-expressing grains were also shrivelled, and the seed weight was decreased by 20%,50%. No ferulic acid esterase activity could be detected in wild-type grains whereas ferulic acid esterase activity was detected in transgenic lines. The grain cell walls had 15%,40% increase in water-unextractable arabinoxylan and a decrease in monomeric ferulic acid between 13% and 34%. In all the plants, the observed changes are consistent with a plant response that serves to minimize the effect of the heterologously expressed enzymes by increasing arabinoxylan biosynthesis and cross-linking. [source] A rice promoter containing both novel positive and negative cis -elements for regulation of green tissue-specific gene expression in transgenic plantsPLANT BIOTECHNOLOGY JOURNAL, Issue 5 2007Meng Cai Summary The tissue-specific expression of transgenes is essential in plant breeding programmes to avoid the fitness costs caused by constitutive expression of a target gene. However, knowledge on the molecular mechanisms of tissue-specific gene expression and practicable tissue-specific promoters is limited. In this study, we identified the cis -acting elements of a tissue-specific promoter from rice, PD54O, and tested the application of original and modified PD54O and its cis -elements in the regulation of gene expression. PD54O is a green tissue-specific promoter. Five novel tissue-specific cis -elements (LPSE1, LPSE2, LPSRE1, LPSRE2, PSE1) were characterized from PD54O. LPSE1 activated gene expression in leaf and young panicle. LPSRE2 suppressed gene expression in leaf, root, young panicle and stem, and PSE1 suppressed gene expression in young panicle and stem. LPSRE1 and LPSE2 had dual roles in the regulation of tissue-specific gene expression; both functioned as activators in leaf, but LPSRE1 acted as a repressor in stem and LPSE2 as a repressor in young panicle and root. Transgenic rice plants carrying cry1Ac encoding Bacillus thuringiensis endotoxin, regulated by PD54O, were resistant to leaf-folders, with no Cry1Ac protein found in endosperm or embryo. A reporter gene regulated by a series of truncated PD54O showed various tissue-specific expression patterns. Different fragments of PD54O fused with the constitutive cauliflower mosaic virus 35S promoter suppressed 35S -regulated gene expression in various tissues. PD54O, truncated PD54O and the tissue-specific cis -elements provide useful tools for the regulation of tissue-specific gene expression in rice breeding programmes. [source] Coupling the GAL4 UAS system with alcR for versatile cell type-specific chemically inducible gene expression in ArabidopsisPLANT BIOTECHNOLOGY JOURNAL, Issue 4 2007Lali Sakvarelidze Summary The Aspergillus alc regulon encodes a transcription factor, ALCR, which regulates transcription from cognate promoters such as alcA(p). In the presence of suitable chemical inducers, ALCR activates gene expression from alcA(p). The alc regulon can be transferred to other species and can be used to control the expression of reporter, metabolic and developmental genes in response to low-level ethanol exposure. In this paper, we describe a versatile system for targeting the alc regulon to specific cell types in Arabidopsis by driving ALCR expression from the GAL4 upstream activator sequence (UAS). Large numbers of Arabidopsis lines are available in which GAL4 is expressed in a variety of spatial patterns and, in turn, drives the expression of any gene cloned downstream of the UAS. We have used a previously characterized line that directs gene expression to the endosperm to demonstrate spatially restricted ethanol-inducible gene expression. We also show that the domain of inducible gene expression can easily be altered by crossing the UAS::ALCR cassette into different driver lines. We conclude that this gene switch can be used to drive gene expression in a highly responsive, but spatially restricted, manner. [source] Bioengineered ,golden' indica rice cultivars with ,-carotene metabolism in the endosperm with hygromycin and mannose selection systemsPLANT BIOTECHNOLOGY JOURNAL, Issue 2 2003Karabi Datta Summary Vitamin-A deficiency (VAD) is a major malnutrition problem in South Asia, where indica rice is the staple food. Indica-type rice varieties feed more than 2 billion people. Hence, we introduced a combination of transgenes using the biolistic system of transformation enabling biosynthesis of provitamin A in the endosperm of several indica rice cultivars adapted to diverse ecosystems of different countries. The rice seed-specific glutelin promoter (Gt-1 P) was used to drive the expression of phytoene synthase (psy), while lycopene ,-cyclase (lcy) and phytoene desaturase (crtI), fused to the transit peptide sequence of the pea-Rubisco small subunit, were driven by the constitutive cauliflower mosaic virus promoter (CaMV35S P). Transgenic plants were recovered through selection with either CaMV35S P driven hph (hygromycin phosphotransferase) gene or cestrum yellow leaf curling virus promoter (CMP) driven pmi (phophomannose isomerase) gene. Molecular and biochemical analyses demonstrated stable integration and expression of the transgenes. The yellow colour of the polished rice grain evidenced the carotenoid accumulation in the endosperm. The colour intensity correlated with the estimated carotenoid content by spectrophotometric and HPLC analysis. Carotenoid level in cooked polished seeds was comparable (with minor loss of xanthophylls) to that in non-cooked seeds of the same transgenic line. The variable segregation pattern in T1 selfing generation indicated single to multiple loci insertion of the transgenes in the genome. This is the first report of using nonantibiotic pmi driven by a novel promoter in generating transgenic indica rice for possible future use in human nutrition. [source] DNA endoreduplication in maize endosperm cells: the effect of exposure to short-term high temperaturePLANT CELL & ENVIRONMENT, Issue 6 2000G. Engelen-Eigles ABSTRACT DNA endoreduplication in Zea mays L. (cv. A619 × W64A) endosperm peaks between 16 and 18 d after pollination (DAP). The physiological function of DNA endoreduplication is not known but it is believed to be important in maize kernel development. In the present study, we investigated how 2, 4 or 6 d of high temperature (35 °C) affected DNA endoreduplication and maize kernel development in comparison with control kernels grown at 25 °C. Data were collected on fresh weight (FW), nuclei number, mitotic index, and DNA endoreduplication. Maize endosperm FW and nuclei number were reduced by exposure to 4 or 6 d of high temperature. At 18 DAP, the 2 d high temperature treatment (HTT) caused a reduction in FW and nuclei number, but had no effect on DNA endoreduplication and average DNA content per endosperm. However, when the exposure to high temperature was increased to 4 or 6 d, FW, nuclei number and the magnitude of DNA endoreduplication were progressively reduced, and the peak mitotic index was delayed compared with the control endosperm. At 18 DAP, the 4 d treatment showed 54·7% of the cells were 3 or 6 C, whereas only 41·2% were 12 C or higher. Six days of high temperature also resulted in a reduction in endosperm FW, nuclei number and a delay in the peak of mitotic index. DNA endoreduplication occurred in the kernels exposed to this treatment, although the magnitude was severely reduced compared with the control kernels. Nuclear DNA content was highly correlated (r= 0·93) with kernel FW, suggesting an important role of DNA endoreduplication in determining endosperm FW. The data suggest that high temperature during endosperm cell division exerted negative effects on DNA endoreduplication by dramatically reducing the nuclei number, leaving fewer nuclei available for DNA endoreduplication. However, the data also suggest that prolonged exposure to high temperature restricts entry of mitotic cells into the endoreduplication phase of the cell cycle. [source] Leaf, floret and seed infection of wheat by Pyrenophora semeniperdaPLANT PATHOLOGY, Issue 4 2003M. A. Campbell Infection processes of Pyrenophora semeniperda on seedling and adult wheat leaves and wheat ears were investigated. Almost 100% germination of conidia occurred on seedling leaves, compared with 20,30% on adult leaves. Appressoria formed over the anticlinal epidermal cell walls and haloes always accompanied infection. Sometimes papillae formed within the leaves as a resistance mechanism. Infection hyphae ramified through the intercellular spaces of the mesophyll resulting in cellular disruption. The infection processes on floral tissues were similar to those observed on leaves; however, no infection occurred on anther, stigmatic or stylar tissues. Infection of ovarian tissue occurred both with and without appressoria formation. Hyphae grew mainly in the epidermal layers and appeared unable to breach the integumental layer as no growth was observed in endosperm or embryo tissues. The optimum dew period temperature for conidial germination was 23·6°C, compared with 19·9°C for lesion development, 20·4°C for the production of infection structures on seedling leaves and 23·7°C for floret infection. Leaf disease development occurred in a logistic manner in response to dew period, with maximum infection observed after 21 h compared with > 48 h in seeds. An initial dark phase during the dew period was necessary for infection and temperature after the dew period had an effect, with significantly more numerous and larger lesions being formed at 15°C compared with 30°C. Seedling leaves were found to be more susceptible than older leaves, under both field and controlled environment conditions. Infection of wheat seeds following inoculation of ears, or after harvest burial of inoculated disease-free seeds, was demonstrated. In the latter, 3-week-old seedlings were slightly stunted, whereas older plants were unaffected. The apparent unimportance of this plant pathogen as a cause of leaf disease in relation to its poor adaptation to dew periods and dew period temperature is discussed, along with the importance of its seed borne characteristics. [source] Molecular systematics in the genus Clintonia and related taxa based on rbcL and matK gene sequence dataPLANT SPECIES BIOLOGY, Issue 2 2001Kazuhiko Hayashi Abstract In an attempt to elucidate the affinity and phylogeny of the disjunct North American,eastern Asian genus Clintonia, two chloroplast genes, rbcL and matK, were sequenced for all five species (Clintonia andrewsiana, Clintonia borealis, Clintonia umbellulata, Clintonia uniflora and Clintonia udensis). Similar sequence data sets for both genes supported the idea that a monophyly of Clintonia consists of two clades, one in eastern Asia and one in North America. The North American lineage resolves into an eastern group and a western group. There are surprisingly few site substitutions within these two genes, notwithstanding the wide morphological diversity of the genus. To root the Clintonia trees, Cardiocrinum (=Lilium) cordatum, Medeola virginiana, Scoliopus bigelovii and Scoliopus hallii were used as outgroup taxa. Similar topologies for Clintonia resulted when both the rbcL and matK gene sequences were combined. However, when an amino acid tree was generated for the matK sequence, all differences between the North American species were reduced to similarities due to synonymous codon sequences. Differentiation patterns of some selected morphological, karyological and embryological characters in Clintonia were also reviewed in comparison to the resulting molecular topologies. The unique, Clintonia -type megasporogenesis that produced identical, maternally derived, diploid zygotes and endosperm coupled to polyploid buffering provides a considerable constraint on variability. A search of possible sister genera to Clintonia was also attempted based on the molecular analyses and outgroup analysis, and Medeola virginiana from eastern North America turned out to be the closest relative found. [source] Proteomics reveal tissue-specific features of the cress (Lepidium sativum L.) endosperm cap proteome and its hormone-induced changes during seed germinationPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2010Kerstin Müller Abstract Mature angiosperm seeds consist of an embryo surrounded by the endosperm and the testa. The endosperm cap that covers the radicle plays a regulatory role during germination and is a major target of abscisic acidinduced inhibition of germination. Cress (Lepidium sativum) is a close relative of the model plant Arabidopsis thaliana (Arabidopsis). Cress seeds offer the unique possibility of performing tissue-specific proteomics due to their larger size while benefiting the genomic tools available for Arabidopsis. This work provides the first description of endosperm cap proteomics during seed germination. An analysis of the proteome of the cress endosperm cap at key stages during germination and after radicle protrusion in the presence and absence of abscisic acid led to the identification of 144 proteins, which were clustered by the changes in their abundances and categorized by function. Proteins with a function in energy production, protein stability and stress response were overrepresented among the identified endosperm cap proteins. This strongly suggests that the cress endosperm cap is not a storage tissue as the cereal endosperm but a metabolically very active tissue regulating the rate of radicle protrusion. [source] Comparative proteomic and transcriptional profiling of a bread wheat cultivar and its derived transgenic line overexpressing a low molecular weight glutenin subunit gene in the endospermPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2008Federico Scossa Abstract We carried out a parallel transcriptional and proteomic comparison of seeds from a transformed bread wheat line that overexpresses a transgenic low molecular weight glutenin subunit gene relative to the corresponding nontransformed genotype. Proteomic analyses showed that, during seed development, several classes of endosperm proteins were differentially accumulated in the transformed endosperm. As a result of the strong increase in the amount of the transgenic protein, the endogenous glutenin subunit, all subclasses of gliadins, and metabolic as well as chloroform/methanol soluble proteins were diminished in the transgenic genotype. The differential accumulation detected by proteomic analyses, both in mature and developing seeds, was paralleled by the corresponding changes in transcript levels detected by microarray experiments. Our results suggest that the most evident effect of the strong overexpression of the transgenic glutenin gene consists in a global compensatory response involving a significant decrease in the amounts of polypeptides belonging to the prolamin superfamily. It is likely that such compensation is a consequence of the diversion of amino acid reserves and translation machinery to the synthesis of the transgenic glutenin subunit. [source] Inactivation of the UGPase1 gene causes genic male sterility and endosperm chalkiness in rice (Oryza sativa L.)THE PLANT JOURNAL, Issue 2 2008Mi-Ok Woo Summary A rice genic male-sterility gene ms-h is recessive and has a pleiotropic effect on the chalky endosperm. After fine mapping, nucleotide sequencing analysis of the ms-h gene revealed a single nucleotide substitution at the 3,-splice junction of the 14th intron of the UDP-glucose pyrophosphorylase 1 (UGPase1; EC2.7.7.9) gene, which causes the expression of two mature transcripts with abnormal sizes caused by the aberrant splicing. An in vitro functional assay showed that both proteins encoded by the two abnormal transcripts have no UGPase activity. The suppression of UGPase by the introduction of a UGPase1-RNAi construct in wild-type plants nearly eliminated seed set because of the male defect, with developmental retardation similar to the ms-h mutant phenotype, whereas overexpression of UGPase1 in ms-h mutant plants restored male fertility and the transformants produced T1 seeds that segregated into normal and chalky endosperms. In addition, both phenotypes were co-segregated with the UGPase1 transgene in segregating T1 plants, which demonstrates that UGPase1 has functional roles in both male sterility and the development of a chalky endosperm. Our results suggest that UGPase1 plays a key role in pollen development as well as seed carbohydrate metabolism. [source] FUSCA3 from barley unveils a common transcriptional regulation of seed-specific genes between cereals and ArabidopsisTHE PLANT JOURNAL, Issue 6 2008Miguel Ángel Moreno-Risueno Summary Accumulation of storage compounds in the embryo and endosperm of developing seeds is a highly regulated process that allows seedling growth upon germination until photosynthetic capacity is acquired. A critical regulatory element in the promoters of seed storage protein (SSP) genes from dicotyledonous species is the RY box, a target of B3-type transcription factors. However, the functionality of this motif in the transcriptional regulation of SSP genes from cereals has not been fully established. We report here the identification and molecular characterization of barley FUSCA3, a B3-type transcription factor as yet uncharacterized in monocotyledonous plants. Our results show that both the barley and Arabidopsis FUS3 genes maintain a conserved functionality for the regulation of SSP genes and anthocyanin biosynthesis in these two distantly related phylogenetic groups. Complementation of the loss-of-function mutant fus3 in Arabidopsis by the barley HvFus3 gene resulted in restored transcription from the At2S3 gene promoter and normal accumulation of anthocyanins in the seed. In barley, HvFUS3 participates in transcriptional activation of the endosperm-specific genes Hor2 and Itr1. HvFUS3, which specifically binds to RY boxes in EMSA experiments, trans -activates Hor2 and Itr1 promoters containing intact RY boxes in transient expression assays in developing endosperms. Mutations in the RY boxes abolished the HvFUS3-mediated trans -activation. HvFus3 transcripts accumulate in the endosperm and in the embryo of developing seeds, peaking at mid maturation phase. Remarkably, HvFUS3 interacts with the Opaque2-like bZIP factor BLZ2 in yeast, and this interaction is essential for full trans -activation of the seed-specific genes in planta. [source] | |||||||||||||||||||||||||