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Sample records for linked maize endosperm

  1. Lipid partitioning in maize (Zea mays L.) endosperm highlights relationships among starch lipids, amylose, and vitreousness.

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    Gayral, Mathieu; Bakan, Bénédicte; Dalgalarrondo, Michele; Elmorjani, Khalil; Delluc, Caroline; Brunet, Sylvie; Linossier, Laurent; Morel, Marie-Hélène; Marion, Didier

    2015-04-08

    Content and composition of maize endosperm lipids and their partition in the floury and vitreous regions were determined for a set of inbred lines. Neutral lipids, i.e., triglycerides and free fatty acids, accounted for more than 80% of endosperm lipids and are almost 2 times higher in the floury than in the vitreous regions. The composition of endosperm lipids, including their fatty acid unsaturation levels, as well as their distribution may be related to metabolic specificities of the floury and vitreous regions in carbon and nitrogen storage and to the management of stress responses during endosperm cell development. Remarkably, the highest contents of starch lipids were observed systematically within the vitreous endosperm. These high amounts of starch lipids were mainly due to lysophosphatidylcholine and were tightly linked to the highest amylose content. Consequently, the formation of amylose-lysophosphatidylcholine complexes has to be considered as an outstanding mechanism affecting endosperm vitreousness.

  2. Lignification of developing maize (Zea mays L.) endosperm transfer cells and starchy endosperm cells

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    Rocha, Sara; Monjardino, Paulo; Mendonça, Duarte; da Câmara Machado, Artur; Fernandes, Rui; Sampaio, Paula; Salema, Roberto

    2014-01-01

    Endosperm transfer cells in maize have extensive cell wall ingrowths that play a key role in kernel development. Although the incorporation of lignin would support this process, its presence in these structures has not been reported in previous studies. We used potassium permanganate staining combined with transmission electron microscopy – energy dispersive X-ray spectrometry as well as acriflavine staining combined with confocal laser scanning microscopy to determine whether the most basal endosperm transfer cells (MBETCs) contain lignified cell walls, using starchy endosperm cells for comparison. We investigated the lignin content of ultrathin sections of MBETCs treated with hydrogen peroxide. The lignin content of transfer and starchy cell walls was also determined by the acetyl bromide method. Finally, the relationship between cell wall lignification and MBETC growth/flange ingrowth orientation was evaluated. MBETC walls and ingrowths contained lignin throughout the period of cell growth we monitored. The same was true of the starchy cells, but those underwent an even more extensive growth period than the transfer cells. Both the reticulate and flange ingrowths were also lignified early in development. The significance of the lignification of maize endosperm cell walls is discussed in terms of its impact on cell growth and flange ingrowth orientation. PMID:24688487

  3. Effect of endosperm mutants on maize seed germination

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    Pajić Zorica

    2004-01-01

    Full Text Available The expression of genetic potential of yielding and quality of a certain genotype depends among other factors on seed quality. Seed is very important not only for the reproduction of the particular plant species, but also, for the contemporary plant production. Each part of maize seed (pericarp endosperm and germ has a specific function in the complex process of germination and emergence. The following three genotypes of different endosperm types were observed: ZPSC 42A (standard grain quality dent hybrid ZPSC 504 su (sweet maize hybrid with a sugary gene and ZPSyn.II sh2 (synthetic population with a shranken2 gene. Seed viability of the stated genotypes was determined by the accepted ISTA methods: standard method accelerating age and cold test. Obtained results point out to differences in the germination capacity of the observed genotypes. The greatest reduction of the germination capacity and the emergence rate was expressed by the application of the accelerating ageing method. Appeared differences are probably a result of the endosperm texture (type, grain weight, sugar content and pericarp thickens and composition.

  4. Maize rough endosperm3 encodes an RNA splicing factor required for endosperm cell differentiation and has a nonautonomous effect on embryo development.

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    Fouquet, Romain; Martin, Federico; Fajardo, Diego S; Gault, Christine M; Gómez, Elisa; Tseung, Chi-Wah; Policht, Tyler; Hueros, Gregorio; Settles, A Mark

    2011-12-01

    Endosperm and embryo development are coordinated via epigenetic regulation and signaling between these tissues. In maize (Zea mays), the endosperm-embryo signals are not known, but endosperm cellularization is a key event for embryos to form shoots and roots. We screened seed mutants for nonautonomous functions in endosperm and embryo development with genetically nonconcordant seeds and identified the recessive mutant rough endosperm3 (rgh3). The wild-type Rgh3 allele is required in the endosperm for embryos to develop and has an autonomous role in embryo and seedling development. Endosperm cell differentiation is defective in rgh3. Results from endosperm cell culture indicate that rgh3 mutants remain in a proliferative state through mid-seed development. Rgh3 encodes the maize U2AF(35) Related Protein (URP), an RNA splicing factor involved in both U2 and U12 splicing. The Rgh3 allele produces at least 19 alternative splice variants with only one isoform encoding a full-length ortholog to URP. The full-length RGH3α isoform localizes to the nucleolus and displays a speckled pattern within the nucleoplasm, and RGH3α colocalizes with U2AF(65). A survey of alternatively spliced transcripts found that, in the rgh3 mutant, a fraction of noncanonical splicing events are altered. Our findings suggest that differentiation of maize endosperm cell types is necessary for embryos to develop. The molecular cloning of Rgh3 suggests that alternative RNA splicing is needed for cell differentiation, development, and plant viability.

  5. Distribution of soluble amino acids in maize endosperm mutants

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    Toro Alejandro Alberto

    2003-01-01

    Full Text Available For human nutrition the main source of vegetable proteins are cereal and legume seeds. The content of total soluble amino acids in mature endosperm of wild-type, opaque and floury maize (Zea mays L. mutants were determined by HPLC. The total absolute concentration of soluble amino acids among the mutants varied depending on the mutant. The o11 and o13 mutants exhibited the highest average content, whereas o10, fl3 and fl1 exhibited the lowest average content. In general, the mutants exhibited similar concentrations of total soluble amino acids when compared to the wild-type lines, with the clear exception of mutants o11 and fl1, with the o11 mutant exhibiting a higher concentration of total soluble amino acids when compared to its wild-type counterpart W22 and the fl1 mutant a lower concentration when compared to its wild-type counterpart Oh43. For methionine, the mutants o2 and o11 and wild-type Oh43 exhibited the highest concentrations of this amino acid. Significant differences were not observed between mutants for other amino acids such as lysine and threonine. The high lysine concentrations obtained originally for these mutants may be due to the amino acids incorporated into storage proteins, but not those present in the soluble form.

  6. Positional cues specify and maintain aleurone cell fate in maize endosperm development.

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    Becraft, P W; Asuncion-Crabb, Y

    2000-09-01

    A genetic analysis of maize aleurone development was conducted. Cell lineage was examined by simultaneously marking cells with C1 for anthocyanin pigmentation in the aleurone and wx1 for amylose synthesis in the starchy endosperm. The aleurone and starchy endosperm share a common lineage throughout development indicating that positional cues specify aleurone fate. Mutants in dek1 block aleurone formation at an early stage and cause peripheral endosperm cells to develop as starchy endosperm. Revertant sectors of a transposon-induced dek1 allele showed that peripheral endosperm cells remain competent to differentiate as aleurone cells until late in development. Ds-induced chromosome breakage was used to generate Dek1 loss-of-function sectors. Events occurring until late development caused aleurone cells to switch fate to starchy endosperm indicating that cell fate is not fixed. Thus, positional cues are required to specify and maintain aleurone fate and Dek1 function is required to respond to these cues. An analysis of additional mutants that disrupt aleurone differentiation suggests a hierarchy of gene functions to specify aleurone cell fate and then control aleurone differentiation. These mutants disrupt aleurone differentiation in reproducible patterns suggesting a relationship to endosperm pattern formation.

  7. Characterization of the imprinting and expression patterns of ZAG2 in maize endosperm and embryo

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    Chaoxian Liu

    2015-02-01

    Full Text Available ZAG2 has been identified as a maternally expressed imprinted gene in maize endosperm. Our study revealed that paternally inherited ZAG2 alleles were imprinted in maize endosperm and embryo at 14 days after pollination (DAP, and consistently imprinted in endosperm at 10, 12, 16, 18, 20, 22, 24, 26, and 28 DAP in reciprocal crosses between B73 and Mo17. ZAG2 alleles were also imprinted in reciprocal crosses between Zheng 58 and Chang 7-2 and between Huang C and 178. ZAG2 alleles exhibited differential imprinting in hybrids of 178 × Huang C and B73 × Mo17, while in other hybrids ZAG2 alleles exhibited binary imprinting. The tissue-specific expression pattern of ZAG2 showed that ZAG2 was expressed at a high level in immature ears, suggesting that ZAG2 plays important roles in not only kernel but ear development.

  8. Cyclin-Dependent Kinase Inhibitors in Maize Endosperm and Their Potential Role in Endoreduplication1

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    Coelho, Cintia M.; Dante, Ricardo A.; Sabelli, Paolo A.; Sun, Yuejin; Dilkes, Brian P.; Gordon-Kamm, William J.; Larkins, Brian A.

    2005-01-01

    Two maize (Zea mays) cyclin-dependent kinase (CDK) inhibitors, Zeama;KRP;1 and Zeama;KRP;2, were characterized and shown to be expressed in developing endosperm. Similar to the CDK inhibitors in Arabidopsis (Arabidopsis thaliana) and tobacco (Nicotiana tabacum), the maize proteins contain a carboxy-terminal region related to the inhibitory domain of the mammalian Cip/Kip inhibitors. Zeama;KRP;1 is present in the endosperm between 7 and 21 d after pollination, a period that encompasses the onset of endoreduplication, while the Zeama;KRP;2 protein declines during this time. Nevertheless, Zeama;KRP;1 accounts for only part of the CDK inhibitory activity that peaks coincident with the endoreduplication phase of endosperm development. In vitro assays showed that Zeama;KRP;1 and Zeama;KRP;2 are able to inhibit endosperm Cdc2-related CKD activity that associates with p13Suc1. They were also shown to specifically inhibit cyclin A1;3- and cyclin D5;1-associated CDK activities, but not cyclin B1;3/CDK. Overexpression of Zeama;KRP;1 in maize embryonic calli that ectopically expressed the wheat dwarf virus RepA protein, which counteracts retinoblastoma-related protein function, led to an additional round of DNA replication without nuclear division. PMID:16055680

  9. Defining the SUMO System in Maize: SUMOylation Is Up-Regulated during Endosperm Development and Rapidly Induced by Stress.

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    Augustine, Robert C; York, Samuel L; Rytz, Thérèse C; Vierstra, Richard D

    2016-07-01

    In response to abiotic and biotic challenges, plants rapidly attach small ubiquitin-related modifier (SUMO) to a large collection of nuclear proteins, with studies in Arabidopsis (Arabidopsis thaliana) linking SUMOylation to stress tolerance via its modification of factors involved in chromatin and RNA dynamics. Despite this importance, little is known about SUMOylation in crop species. Here, we describe the plant SUMO system at the phylogenetic, biochemical, and transcriptional levels with a focus on maize (Zea mays). In addition to canonical SUMOs, land plants encode a loosely constrained noncanonical isoform and a variant containing a long extension upstream of the signature β-grasp fold, with cereals also expressing a novel diSUMO polypeptide bearing two SUMO β-grasp domains in tandem. Maize and other cereals also synthesize a unique SUMO-conjugating enzyme variant with more restricted expression patterns that is enzymatically active despite a distinct electrostatic surface. Maize SUMOylation primarily impacts nuclear substrates, is strongly induced by high temperatures, and displays a memory that suppresses subsequent conjugation. Both in-depth transcript and conjugate profiles in various maize organs point to tissue/cell-specific functions for SUMOylation, with potentially significant roles during embryo and endosperm maturation. Collectively, these studies define the organization of the maize SUMO system and imply important functions during seed development and stress defense.

  10. Dynamic expression of imprinted genes associates with maternally controlled nutrient allocation during maize endosperm development.

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    Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu

    2013-09-01

    In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation.

  11. Identification and characterization of paternal-preferentially expressed gene NF-YC8 in maize endosperm.

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    Mei, Xiupeng; Liu, Chaoxian; Yu, Tingting; Liu, Xiaoli; Xu, De; Wang, Jiuguang; Wang, Guoqiang; Cai, Yilin

    2015-10-01

    Gene imprinting describes an epigenetic phenomenon, whereby genetically identical alleles are differentially expressed dependent on parent-of-origin. Some imprinted genes belonged to NUCLEAR FACTOR Y (NF-Y) transcription factors, which were involved in many important metabolic processes in plant. The characterizations of imprinted genes are of great importance for their function exploration. In this paper, 15 non-redundant NF-YC genes were identified in the maize genome and the paternally expressed gene NF-YC8 was further analyzed. NF-YC8 primarily expressed in maize immature ear and tassel and phylogenetic analysis showed that NF-YC8 was highly homologous with Arabidopsis thaliana NF-YC2 genes which function in regulation of the flowering processes, ER stress response. Furthermore, NF-YC8 was a differential, gene-specific imprinted gene at 14 DAP and persistently imprinted throughout later endosperm development in the B73/Mo17 genetic background. Bisulfite sequencing for NF-YC8 in maize endosperm showed that the paternal alleles were higher methylated (CG, CHG and CHH contexts) than maternal alleles in the 5' upstream region, and the coding region was highly methylated in CG context. Additionally, TE (CG, CHG and CHH contexts) and repetitive region (CG and CHG contexts) were all highly methylated. These results are the first description of evolution and molecular characterization of maize NF-YC8 and will provide new references for maize NF-YC genetic analysis.

  12. RNA sequencing of laser-capture microdissected compartments of the maize kernel identifies regulatory modules associated with endosperm cell differentiation.

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    Zhan, Junpeng; Thakare, Dhiraj; Ma, Chuang; Lloyd, Alan; Nixon, Neesha M; Arakaki, Angela M; Burnett, William J; Logan, Kyle O; Wang, Dongfang; Wang, Xiangfeng; Drews, Gary N; Yadegari, Ramin

    2015-03-01

    Endosperm is an absorptive structure that supports embryo development or seedling germination in angiosperms. The endosperm of cereals is a main source of food, feed, and industrial raw materials worldwide. However, the genetic networks that regulate endosperm cell differentiation remain largely unclear. As a first step toward characterizing these networks, we profiled the mRNAs in five major cell types of the differentiating endosperm and in the embryo and four maternal compartments of the maize (Zea mays) kernel. Comparisons of these mRNA populations revealed the diverged gene expression programs between filial and maternal compartments and an unexpected close correlation between embryo and the aleurone layer of endosperm. Gene coexpression network analysis identified coexpression modules associated with single or multiple kernel compartments including modules for the endosperm cell types, some of which showed enrichment of previously identified temporally activated and/or imprinted genes. Detailed analyses of a coexpression module highly correlated with the basal endosperm transfer layer (BETL) identified a regulatory module activated by MRP-1, a regulator of BETL differentiation and function. These results provide a high-resolution atlas of gene activity in the compartments of the maize kernel and help to uncover the regulatory modules associated with the differentiation of the major endosperm cell types. © 2015 American Society of Plant Biologists. All rights reserved.

  13. DNA content in embryo and endosperm of maize kernel (Zea mays L.): impact on GMO quantification.

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    Trifa, Youssef; Zhang, David

    2004-03-10

    PCR-based techniques are the most widely used methods for the quantification of genetically modified organisms (GMOs) through the determination of the ratio of transgenic DNA to total DNA. It is shown that the DNA content per mass unit is significantly different among 10 maize cultivars. The DNA contents of endosperms, embryos, and teguments of individual kernels from 10 maize cultivars were determined. According to our results, the tegument's DNA ratio reaches at maximum 3.5% of the total kernel's DNA, whereas the endosperm's and the embryo's DNA ratios are nearly equal to 50%. The embryo cells are diploid and made of one paternal and one maternal haploid genome, whereas the endosperm is constituted of triploid cells made of two maternal haploid genomes and one paternal haploid genome. Therefore, it is shown, in this study, that the accuracy of the GMO quantification depends on the reference material used as well as on the category of the transgenic kernels present in the mixture.

  14. Proteomic Comparison of Basal Endosperm in Maize miniature1 Mutant and its Wild-type Mn1

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    Cecilia eSilva-Sanchez

    2013-06-01

    Full Text Available Developing endosperm in maize seed is a major site for biosynthesis and storage of starch and proteins, and of immense economic importance for its role in food, feed and biofuel production. The basal part of endosperm performs a major role in solute, water and nutrition acquisition from mother plant to sustain these functions. The miniature1 (mn1 mutation is a loss-of-function mutation of the Mn1-encoded cell wall invertase that is entirely expressed in the basal endosperm and is essential for many of the metabolic and signaling functions associated with metabolically released hexose sugars in developing endosperm. Here we report a comparative proteomic study between Mn1 and mn1 basal endosperm to better understand basis of pleiotropic effects on many diverse traits in the mutant. Specifically, we used iTRAQ based quantitative proteomics combined with Gene Ontology and bioinformatics to understand functional basis of the proteomic information. A total of 2518 proteins were identified from soluble and cell wall associated protein fractions; of these 131 proteins were observed to be differentially expressed in the two genotypes. The main functional groups of proteins that were significantly different were those involved in the carbohydrate metabolic and catabolic process, and cell homeostasis. The study constitutes the first proteomic analysis of basal endosperm cell layers in relation to endosperm growth and development in maize.

  15. Pullulanase and Starch Synthase III Are Associated with Formation of Vitreous Endosperm in Quality Protein Maize.

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    Hao Wu

    Full Text Available The opaque-2 (o2 mutation of maize increases lysine content, but the low seed density and soft texture of this type of mutant are undesirable. Lines with modifiers of the soft kernel phenotype (mo2 called "Quality Protein Maize" (QPM have high lysine and kernel phenotypes similar to normal maize. Prior research indicated that the formation of vitreous endosperm in QPM might involve changes in starch granule structure. In this study, we focused on analysis of two starch biosynthetic enzymes that may influence kernel vitreousness. Analysis of recombinant inbred lines derived from a cross of W64Ao2 and K0326Y revealed that pullulanase activity had significant positive correlation with kernel vitreousness. We also found that decreased Starch Synthase III abundance may decrease the pullulanase activity and average glucan chain length given the same Zpu1 genotype. Therefore, Starch Synthase III could indirectly influence the kernel vitreousness by affecting pullulanase activity and coordinating with pullulanase to alter the glucan chain length distribution of amylopectin, resulting in different starch structural properties. The glucan chain length distribution had strong positive correlation with the polydispersity index of glucan chains, which was positively associated with the kernel vitreousness based on nonlinear regression analysis. Therefore, we propose that pullulanase and Starch Synthase III are two important factors responsible for the formation of the vitreous phenotype of QPM endosperms.

  16. Heterologous expression of cellobiohydrolase II (Cel6A) in maize endosperm.

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    Devaiah, Shivakumar Pattada; Requesens, Deborah Vicuna; Chang, Yeun-Kyung; Hood, Kendall R; Flory, Ashley; Howard, John A; Hood, Elizabeth E

    2013-06-01

    The technology of converting lignocellulose to biofuels has advanced swiftly over the past few years, and enzymes are a significant constituent of this technology. In this regard, cost effective production of cellulases has been the focus of research for many years. One approach to reach cost targets of these enzymes involves the use of plants as bio-factories. The application of this technology to plant biomass conversion for biofuels and biobased products has the potential for significantly lowering the cost of these products due to lower enzyme production costs. Cel6A, one of the two cellobiohydrolases (CBH II) produced by Hypocrea jecorina, is an exoglucanase that cleaves primarily cellobiose units from the non-reducing end of cellulose microfibrils. In this work we describe the expression of Cel6A in maize endosperm as part of the process to lower the cost of this dominant enzyme for the bioconversion process. The enzyme is active on microcrystalline cellulose as exponential microbial growth was observed in the mixture of cellulose, cellulases, yeast and Cel6A, Cel7A (endoglucanase), and Cel5A (cellobiohydrolase I) expressed in maize seeds. We quantify the amount accumulated and the activity of the enzyme. Cel6A expressed in maize endosperm was purified to homogeneity and verified using peptide mass finger printing.

  17. Impaired auxin biosynthesis in the defective endosperm18 mutant is due to mutational loss of expression in the ZmYuc1 gene encoding endosperm-specific YUCCA1 protein in maize.

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    A seed-specific maize mutant, defective endosperm18 (de18), accumulates approximately 40% less dry mass and 10- to 15- fold less auxin (IAA) as compared to the De18; however, a causal basis of these changes is not known. Cellular analyses here showed that the de18 developing endosperm had lower tota...

  18. Introgression of opaque2 into Waxy Maize Causes Extensive Biochemical and Proteomic Changes in Endosperm.

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    Zhiqiang Zhou

    Full Text Available Waxy maize is prevalently grown in China and other countries due to the excellent characters and economic value. However, its low content of lysine can't meet the nutritional requirements of humans and livestock. In the present study, we introgressed the opaque2 (o2 allele into waxy maize line Zhao OP-6/O2O2 by using marker-assisted selection (MAS technique and successfully improved the lysine content and quality of waxy maize. Transcript abundance analysis indicated that the wx1 expression levels had no difference between Zhao OP-6/o2o2 and Zhao OP-6/O2O2. However, Zhao OP-6/o2o2 was characterized by a phenotype of hard and vitreous kernels and accumulation of protein bodies at smaller size (one third of that of parents but in larger numbers. Biochemical analyses showed that Zhao OP-6/o2o2 had 16.7% less free amino acids than Zhao OP-6/O2O2, especially those derived from glycolytic intermediates, but its content of lysine was increased by 51.6% (0.47% vs. 0.31%. The content of amylopectin was 98.5% in Zhao OP-6/o2o2, significantly higher than that in Zhao OP-6/O2O2 (97.7%. Proteomic analyses indicated that o2 introgression not only decreased the accumulation of various zein proteins except for 27-kDa γ-zein, but also affected other endosperm proteins related to amino acid biosynthesis, starch-protein balance, stress response and signal transduction. This study gives us an intriguing insight into the metabolism changes in endosperm of waxy maize introgressed with opaque2.

  19. Improved Evidence-Based Genome-scale Metabolic Models for Maize Leaf, Embryo, and Endosperm

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    Seaver, Samuel M.D.; Frelin, Oceane; Bradbury, Louis M.T.; Zarecki, Raphy; Ruppin, Eytan; Hanson, Andrew D.; Henry, Christopher S.

    2015-03-10

    There is a growing demand for genome-scale metabolic reconstructions for plants, fueled by the need to understand the metabolic basis of crop yield and by progress in genome and transcriptome sequencing. Methods are also required to enable the interpretation of plant transcriptome data to study how cellular metabolic activity varies under different growth conditions or even within different organs, tissues, and developmental stages. Such methods depend extensively on the accuracy with which genes have been mapped to the biochemical reactions in the plant metabolic pathways. Errors in these mappings lead to metabolic reconstructions with an inflated number of reactions and possible generation of unreliable metabolic phenotype predictions. Here we introduce a new evidence-based genome-scale metabolic reconstruction of maize, with significant improvements in the quality of the gene-reaction associations included within our model. We also present a new approach for applying our model to predict active metabolic genes based on transcriptome data. This method includes a minimal set of reactions associated with low expression genes to enable activity of a maximum number of reactions associated with high expression genes. We apply this method to construct an organ-specific model for the maize leaf, and tissue specific models for maize embryo and endosperm cells. We validate our models using fluxomics data for the endosperm and embryo, demonstrating an improved capacity of our models to fit the available fluxomics data. All models are publicly available via the DOE Systems Biology Knowledgebase and PlantSEED, and our new method is generally applicable for analysis transcript profiles from any plant, paving the way for further in silico studies with a wide variety of plant genomes.

  20. Improved Evidence-Based Genome-scale Metabolic Models for Maize Leaf, Embryo, and Endosperm.

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    Samuel eSeaver

    2015-03-01

    Full Text Available There is a growing demand for genome-scale metabolic reconstructions for plants, fueled by the need to understand the metabolic basis of crop yield and by progress in genome and transcriptome sequencing. Methods are also required to enable the interpretation of plant transcriptome data to study how cellular metabolic activity varies under different growth conditions or even within different organs, tissues, and developmental stages. Such methods depend extensively on the accuracy with which genes have been mapped to the biochemical reactions in the plant metabolic pathways. Errors in these mappings lead to metabolic reconstructions with an inflated number of reactions and possible generation of unreliable metabolic phenotype predictions. Here we introduce a new evidence-based genome-scale metabolic reconstruction of maize, with significant improvements in the quality of the gene-reaction associations included within our model. We also present a new approach for applying our model to predict active metabolic genes based on transcriptome data. This method includes a minimal set of reactions associated with low expression genes to enable activity of a maximum number of reactions associated with high expression genes. We apply this method to construct an organ-specific model for the maize leaf, and tissue specific models for maize embryo and endosperm cells. We validate our models using fluxomics data for the endosperm and embryo, demonstrating an improved capacity of our models to fit the available fluxomics data. All models are publicly available via the DOE Systems Biology Knowledgebase and PlantSEED, and our new method is generally applicable for analysis transcript profiles from any plant, paving the way for further in silico studies with a wide variety of plant genomes.

  1. Temporal small RNA transcriptome profiling unraveled partitioned miRNA expression in developing maize endosperms between reciprocal crosses

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    Mingming eXin

    2015-09-01

    Full Text Available In angiosperms, the endosperm nurtures embryo and provides nutrients for seed germination. We have performed high-throughput small RNA transcriptome sequencing of kernels at 0, 3, and 5 days after pollination (DAP and endosperms at 7, 10, and 15 DAP by using B73 and Mo17 reciprocal crosses in previous study. Here, we further explored these small RNA-seq data to investigate the potential roles of miRNAs in regulating gene expression process. In total, 57 conserved miRNAs and 18 novel miRNAs were observed highly expressed in maize endosperm. Temporal expression profiling indicates these miRNAs exhibited dynamic and partitioned expression patterns at different developmental stages between maize reciprocal crosses, and qRT-PCR results further confirmed our observation. In addition, we found a subset of distinct tandem miRNAs are generated from a single stem-loop structure in maize which might be conserved in monocots. Furthermore, a SNP variation of Zma-miR408-5p at 11th base position was characterized between B73 and Mo17 which leads to completely different functions in repressing targets. More interestingly, Zma-miR408-5p exhibited B73-biased expression pattern in the B73 and Mo17 reciprocal hybrid endosperms at 7, 10 and 15 DAP according to the reads abundance with SNPs and CAPS experiment.

  2. Functions of heteromeric and homomeric isoamylase-type starch-debranching enzymes in developing maize endosperm.

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    Kubo, Akiko; Colleoni, Christophe; Dinges, Jason R; Lin, Qiaohui; Lappe, Ryan R; Rivenbark, Joshua G; Meyer, Alexander J; Ball, Steven G; James, Martha G; Hennen-Bierwagen, Tracie A; Myers, Alan M

    2010-07-01

    Functions of isoamylase-type starch-debranching enzyme (ISA) proteins and complexes in maize (Zea mays) endosperm were characterized. Wild-type endosperm contained three high molecular mass ISA complexes resolved by gel permeation chromatography and native-polyacrylamide gel electrophoresis. Two complexes of approximately 400 kD contained both ISA1 and ISA2, and an approximately 300-kD complex contained ISA1 but not ISA2. Novel mutations of sugary1 (su1) and isa2, coding for ISA1 and ISA2, respectively, were used to develop one maize line with ISA1 homomer but lacking heteromeric ISA and a second line with one form of ISA1/ISA2 heteromer but no homomeric enzyme. The mutations were su1-P, which caused an amino acid substitution in ISA1, and isa2-339, which was caused by transposon insertion and conditioned loss of ISA2. In agreement with the protein compositions, all three ISA complexes were missing in an ISA1-null line, whereas only the two higher molecular mass forms were absent in the ISA2-null line. Both su1-P and isa2-339 conditioned near-normal starch characteristics, in contrast to ISA-null lines, indicating that either homomeric or heteromeric ISA is competent for starch biosynthesis. The homomer-only line had smaller, more numerous granules. Thus, a function of heteromeric ISA not compensated for by homomeric enzyme affects granule initiation or growth, which may explain evolutionary selection for ISA2. ISA1 was required for the accumulation of ISA2, which is regulated posttranscriptionally. Quantitative polymerase chain reaction showed that the ISA1 transcript level was elevated in tissues where starch is synthesized and low during starch degradation, whereas ISA2 transcript was relatively abundant during periods of either starch biosynthesis or catabolism.

  3. Control of cell proliferation, endoreduplication, cell size, and cell death by the retinoblastoma-related pathway in maize endosperm

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    Sabelli, Paolo A.

    2013-04-22

    The endospermof cereal grains is one of the most valuable products of modern agriculture. Cereal endosperm development comprises different phases characterized by mitotic cell proliferation, endoreduplication, the accumulation of storage compounds, and programmed cell death. Although manipulation of these processes could maximize grain yield, how they are regulated and integrated is poorly understood. We show that the Retinoblastoma-related (RBR) pathway controls key aspects of endosperm development in maize. Down-regulation of RBR1 by RNAi resulted in up-regulation of RBR3-type genes, as well as the MINICHROMOSOME MAINTENANCE 2-7 gene family and PROLIFERATING CELL NUCLEAR ANTIGEN, which encode essential DNA replication factors. Both the mitotic and endoreduplication cell cycles were stimulated. Developing transgenic endosperm contained 42-58% more cells and ~70% more DNA than wild type, whereas there was a reduction in cell and nuclear sizes. In addition, cell death was enhanced. The DNA content of mature endosperm increased 43% upon RBR1 downregulation, whereas storage protein content and kernel weight were essentially not affected. Down-regulation of both RBR1 and CYCLIN DEPENDENT KINASE A (CDKA);1 indicated that CDKA;1 is epistatic to RBR1 and controls endoreduplication through an RBR1- dependent pathway. However, the repressive activity of RBR1 on downstream targets was independent from CDKA;1, suggesting diversification of RBR1 activities. Furthermore, RBR1 negatively regulated CDK activity, suggesting the presence of a feedback loop. These results indicate that the RBR1 pathway plays a major role in regulation of different processes during maize endosperm development and suggest the presence of tissue/organlevel regulation of endosperm/seed homeostasis.

  4. Dynamic Expression of Imprinted Genes Associates with Maternally Controlled Nutrient Allocation during Maize Endosperm Development[W][OPEN

    Science.gov (United States)

    Xin, Mingming; Yang, Ruolin; Li, Guosheng; Chen, Hao; Laurie, John; Ma, Chuang; Wang, Dongfang; Yao, Yingyin; Larkins, Brian A.; Sun, Qixin; Yadegari, Ramin; Wang, Xiangfeng; Ni, Zhongfu

    2013-01-01

    In angiosperms, the endosperm provides nutrients for embryogenesis and seed germination and is the primary tissue where gene imprinting occurs. To identify the imprintome of early developing maize (Zea mays) endosperm, we performed high-throughput transcriptome sequencing of whole kernels at 0, 3, and 5 d after pollination (DAP) and endosperms at 7, 10, and 15 DAP, using B73 by Mo17 reciprocal crosses. We observed gradually increased expression of paternal transcripts in 3- and 5-DAP kernels. In 7-DAP endosperm, the majority of the genes tested reached a 2:1 maternal versus paternal ratio, suggesting that paternal genes are nearly fully activated by 7 DAP. A total of 116, 234, and 63 genes exhibiting parent-specific expression were identified at 7, 10, and 15 DAP, respectively. The largest proportion of paternally expressed genes was at 7 DAP, mainly due to the significantly deviated parental allele expression ratio of these genes at this stage, while nearly 80% of the maternally expressed genes (MEGs) were specific to 10 DAP and were primarily attributed to sharply increased expression levels compared with the other stages. Gene ontology enrichment analysis of the imprinted genes suggested that 10-DAP endosperm-specific MEGs are involved in nutrient uptake and allocation and the auxin signaling pathway, coincident with the onset of starch and storage protein accumulation. PMID:24058158

  5. Binding of ABI4 to a CACCG motif mediates the ABA-induced expression of the ZmSSI gene in maize (Zea mays L.) endosperm.

    Science.gov (United States)

    Hu, Yu-Feng; Li, Yang-Ping; Zhang, Junjie; Liu, Hanmei; Tian, Mengliang; Huang, Yubi

    2012-10-01

    Starch synthase I (SSI) contributes the majority of the starch synthase activity in developing maize endosperm. In this work, the effects of various plant hormones and sugars on the expression of the starch synthase I gene (ZmSSI) in developing maize endosperms were examined. The accumulation of ZmSSI mRNA was induced using abscisic acid (ABA) but not with glucose, sucrose, or gibberellin treatment. To investigate the molecular mechanism underlying this effect, the ZmSSI promoter region (-1537 to +51) was isolated and analysed. A transient expression assay in maize endosperm tissue showed that the full-length ZmSSI promoter is activated by ABA. The results of deletion and mutation assays demonstrated that a CACCG motif in the ZmSSI promoter is responsible for the ABA inducibility. The results of binding shift assays indicated that this CACCG motif interacts with the maize ABI4 protein in vitro. The overexpression of ABI4 in endosperm tissue enhanced the activity of a promoter containing the CACCG motif in the absence of ABA treatment. Expression pattern analysis indicated that the transcription pattern of ABI4 in the developing maize endosperm was induced by ABA treatment but was only slightly affected by glucose or sucrose treatment. Taken together, these data indicate that ABI4 binds to the CACCG motif in the ZmSSI promoter and mediates its ABA inducibility.

  6. Responses to Hypoxia and Endoplasmic Reticulum Stress Discriminate the Development of Vitreous and Floury Endosperms of Conventional Maize (Zea mays) Inbred Lines.

    Science.gov (United States)

    Gayral, Mathieu; Elmorjani, Khalil; Dalgalarrondo, Michèle; Balzergue, Sandrine M; Pateyron, Stéphanie; Morel, Marie-Hélène; Brunet, Sylvie; Linossier, Laurent; Delluc, Caroline; Bakan, Bénédicte; Marion, Didier

    2017-01-01

    Major nutritional and agronomical issues relating to maize (Zea mays) grains depend on the vitreousness/hardness of its endosperm. To identify the corresponding molecular and cellular mechanisms, most studies have been conducted on opaque/floury mutants, and recently on Quality Protein Maize, a reversion of an opaque2 mutation by modifier genes. These mutant lines are far from conventional maize crops. Therefore, a dent and a flint inbred line were chosen for analysis of the transcriptome, amino acid, and sugar metabolites of developing central and peripheral endosperm that is, the forthcoming floury and vitreous regions of mature seeds, respectively. The results suggested that the formation of endosperm vitreousness is clearly associated with significant differences in the responses of the endosperm to hypoxia and endoplasmic reticulum stress. This occurs through a coordinated regulation of energy metabolism and storage protein (i.e., zein) biosynthesis during the grain-filling period. Indeed, genes involved in the glycolysis and tricarboxylic acid cycle are up-regulated in the periphery, while genes involved in alanine, sorbitol, and fermentative metabolisms are up-regulated in the endosperm center. This spatial metabolic regulation allows the production of ATP needed for the significant zein synthesis that occurs at the endosperm periphery; this finding agrees with the zein-decreasing gradient previously observed from the sub-aleurone layer to the endosperm center. The massive synthesis of proteins transiting through endoplasmic reticulum elicits the unfolded protein responses, as indicated by the splicing of bZip60 transcription factor. This splicing is relatively higher at the center of the endosperm than at its periphery. The biological responses associated with this developmental stress, which control the starch/protein balance, leading ultimately to the formation of the vitreous and floury regions of mature endosperm, are discussed.

  7. Aberrant splicing in maize rough endosperm3 reveals a conserved role for U12 splicing in eukaryotic multicellular development

    Science.gov (United States)

    Barbazuk, W. Brad

    2017-01-01

    RNA splicing of U12-type introns functions in human cell differentiation, but it is not known whether this class of introns has a similar role in plants. The maize ROUGH ENDOSPERM3 (RGH3) protein is orthologous to the human splicing factor, ZRSR2. ZRSR2 mutations are associated with myelodysplastic syndrome (MDS) and cause U12 splicing defects. Maize rgh3 mutants have aberrant endosperm cell differentiation and proliferation. We found that most U12-type introns are retained or misspliced in rgh3. Genes affected in rgh3 and ZRSR2 mutants identify cell cycle and protein glycosylation as common pathways disrupted. Transcripts with retained U12-type introns can be found in polysomes, suggesting that splicing efficiency can alter protein isoforms. The rgh3 mutant protein disrupts colocalization with a known ZRSR2-interacting protein, U2AF2. These results indicate conserved function for RGH3/ZRSR2 in U12 splicing and a deeply conserved role for the minor spliceosome to promote cell differentiation from stem cells to terminal fates. PMID:28242684

  8. Proteomic analysis of the enzymes involved in the starch biosynthesis of maize with different endosperm type and characterization of the starch.

    Science.gov (United States)

    Juárez-García, Erika; Agama-Acevedo, Edith; Gómez-Montiel, Noel Orlando; Pando-Robles, Victoria; Bello-Pérez, Luis Arturo

    2013-08-30

    The characterization of starch maize with different endosperm type and the proteomic analysis of its biosynthetic enzymes at 20 and 50 days after pollination (DAP) was carried out. There were differences between both endosperm types at 20 DAP, mainly in starch accumulation, amylose content, granule size and crystallinity percentage, whereas at 50 DAP the differences found were not relevant in the case of starch content, granule size, chain length distribution and thermal properties. SSSI, SBEIIb and GBSSI enzymes were identified; however, SBEIIb was only identified in two samples: floury endosperm at 20 DAP and vitreous at 50 DAP. Starch did not show differences in its morphological or structural characteristics in either endosperm on reaching maturity. Starch biosynthetic enzymes identified by matrix-assisted laser desorption/ionization-time of flight did not show a relationship to starch structure. © 2013 Society of Chemical Industry.

  9. The regulation of gene expression in transformed maize aleurone and endosperm protoplasts. Analysis of promoter activity, intron enhancement, and mRNA untranslated regions on expression.

    Science.gov (United States)

    Gallie, D R; Young, T E

    1994-11-01

    Gene expression in the aleurone and endosperm is highly regulated during both seed development and germination. Studies of alpha-amylase expression in the aleurone of barley (Hordeum vulgare) have generated the current paradigm for hormonal control of gene expression in germinating cereal grain. Gene expression studies in both the aleurone and endosperm tissues of maize (Zea mays) seed have been hampered because of a lack of an efficient transformation system. We report here the rapid isolation of protoplasts from maize aleurone and endosperm tissue, their transformation using polyethylene glycol or electroporation, and the regulation of gene expression in these cells. Adh1 promoter activity was reduced relative to the 35S promoter in aleurone and endosperm protoplasts compared to Black Mexican Sweet suspension cells in which it was nearly as strong as the 35S promoter. Intron-mediated stimulation of expression was substantially higher in transformed aleurone or endosperm protoplasts than in cell-suspension culture protoplasts, and the data suggest that the effect of an intron may be affected by cell type. To examine cytoplasmic regulation, the 5' and 3' untranslated regions from a barley alpha-amylase were fused to the firefly luciferase-coding region, and their effect on translation and mRNA stability was examined following the delivery of in vitro synthesized mRNA to aleurone and endosperm protoplasts. The alpha-amylase untranslated regions regulated translational efficiency in a tissue-specific manner, increasing translation in aleurone or endosperm protoplasts but not in maize or carrot cell-suspension protoplasts, in animal cells, or in in vitro translation lysates.

  10. Construction of chimeric enzymes out of maize endosperm branching enzymes I and II: activity and properties.

    Science.gov (United States)

    Kuriki, T; Stewart, D C; Preiss, J

    1997-11-14

    Branching enzyme I and II isoforms from maize endosperm (mBE I and mBE II, respectively) have quite different properties, and to elucidate the domain(s) that determines the differences, chimeric genes consisting of part mBE I and part mBE II were constructed. When expressed under the control of the T7 promoter in Escherichia coli, several of the chimeric enzymes were inactive. The only fully active chimeric enzyme was mBE II-I BspHI, in which the carboxyl-terminal part of mBE II was exchanged for that of mBE I at a BspHI restriction site and was purified to homogeneity and characterized. Another chimeric enzyme, mBE I-II HindIII, in which the amino-terminal end of mBE II was replaced with that of mBE I, had very little activity and was only partially characterized. The purified mBE II-I BspHI exhibited higher activity than wild-type mBE I and mBE II when assayed by the phosphorylase a stimulation assay. mBE II-I BspHI had substrate specificity (preference for amylose rather than amylopectin) and catalytic capacity similar to mBE I, despite the fact that only the carboxyl terminus was from mBE I, suggesting that the carboxyl terminus may be involved in determining substrate specificity and catalytic capacity. In chain transfer experiments, mBE II-I BspHI transferred more short chains (with a degree of polymerization of around 6) in a fashion similar to mBE II. In contrast, mBE I-II HindIII transferred more long chains (with a degree of polymerization of around 11-12), similar to mBE I, suggesting that the amino terminus of mBEs may play a role in the size of oligosaccharide chain transferred. This study challenges the notion that the catalytic centers for branching enzymes are exclusively located in the central portion of the enzyme; it suggests instead that the amino and carboxyl termini may also be involved in determining substrate preference, catalytic capacity, and chain length transfer.

  11. Two maize END-1 orthologs, BETL9 and BETL9like, are transcribed in a non-overlapping spatial pattern on the outer surface of the developing endosperm

    Directory of Open Access Journals (Sweden)

    Joaquín eRoyo

    2014-05-01

    Full Text Available In the course of a project aimed to isolate transfer cells-specific genes in maize endosperm we have identified the BETL9 gene. BETL9 encodes for a small protein very similar in sequence to the product of the barley transfer cell-specific gene end-1. Both BETL9 and END-1 proteins are lipid transfer proteins, but their function is currently unknown. In situ hybridization analysis confirms that the BETL9 gene is exclusively transcribed in the basal endosperm transfer cell layer during seed development since 10 days after pollination. However, immunolocalization data indicates that the BETL9 protein accumulates in the maternal placento-chalaza cells located just beside the transfer cell layer. This suggests that the BETL9 protein should be transported to the maternal side to exert its, still unknown, function. In addition, we have identified a second maize gene very similar in sequence to BETL9 and we have named it BETL9like. In situ hybridization shows that BETL9like is also specifically transcribed in the developing maize endosperm within the same time frame that BETL9, but in this case it is exclusively expressed in the aleurone cell layer. Consequently, the BETL9 and BETL9like genes are transcribed in a non-overlapping pattern on the outer surface of the maize endosperm. The BETL9 and BETL9like promoter sequences, fused to the GUS reporter gen, accurately reflected the expression pattern observed for the genes in maize. Finally, we have identified in the Arabidopsis genome a set of four genes orthologous to BETL9 and BETL9like and analysed the activity of their promoters in Arabidopsis transgenic plants carrying fusions of their promoter sequences to the GUS reporter. As in the case of the maize genes, the Arabidopsis orthologs showed highly complementary expression patterns.

  12. A comparative glycoproteome study of developing endosperm in the hexose-deficient miniature1 (mn1 seed mutant and its wild type Mn1 in maize

    Directory of Open Access Journals (Sweden)

    Cecilia eSilva-Sanchez

    2014-02-01

    Full Text Available In maize developing seeds, transfer cells are prominently located at the basal endosperm transfer layer (BETL. As the first filial cell layer, BETL is a gateway to sugars, nutrients and water from mother plant; and anchor of numerous functions such as sucrose turnover, auxin and cytokinin biosynthesis/accumulation, energy metabolism, defense response, and signaling between maternal and filial generations. Previous studies showed that basal developing endosperms of miniature1 (mn1 mutant seeds lacking the Mn1-encoded cell wall invertase II, are also deficient for hexose. Given the role of glucose as one of the key sugars in protein glycosylation and proper protein folding; we performed a comparative large scale glycoproteome profiling of total proteins of these two genotypes (mn1 mutant vs Mn1 wild type using 2D gel electrophoresis and glycosylation/total protein staining, followed by image analysis. Protein identification was done by LC-MS/MS. A total of 413 spots were detected; from which, 113 spots matched between the two genotypes. Of these, 45 showed > 20% decrease/increase in glycosylation level and were selected for protein identification. A large number of identified proteins showed decreased glycosylation levels in mn1 developing endosperms as compared to the Mn1. Functional classification of proteins, showed mainly of post-translational modification, protein turnover, chaperone activities, carbohydrate and amino acid biosynthesis / transport, and cell wall biosynthesis. These proteins and activities were related to endoplasmic reticulum (ER stress and unfolded protein response (UPR as a result of the low glycolsylation levels of the mutant proteins. Overall, these results provide for the first time a global glycoproteome profile of maize BETL-enriched basal endosperm to better understand their role in seed development in maize.

  13. Molecular Genetic Traits Influencing Maize Endosperm Development and Value: Closeout Report for DOE Grant DE-FG02-96ER20242

    Energy Technology Data Exchange (ETDEWEB)

    Brian A. Larkins

    2012-09-12

    Development of the endosperm in cereal grasses entails different phases characterized by cell division, endoreduplication, accumulation of storage metabolites and cell death, which need to be carried out in an orderly fashion. While correct regulation of the cell cycle plays an essential role in endosperm development, the key regulatory factors and how the cell cycle interfaces with other pathways in this developmental context are largely unknown. We investigated the cyclin-dependent kinase (CDK)-retinoblastoma pathway and how it controls the cell cycle and coordinates it with other processes during maize endosperm development. Retinoblastoma-related (RBR) proteins may be inactivated through CDK-mediated phosphorylation, but the identity of the responsible kinase in maize is unknown. We have previously shown that down-regulation of CDKA;1 severely inhibits the endoreduplication cell cycle and suggested that CDK may be an up-stream regulator of the retinoblastoma pathway. We discovered two types of maize RBR genes, RBR1 and RBR3, which differ in terms of structure, regulation and function. Phylogenetic analyses indicate that these genes may be distinctive features of the Poaceae. We found that RBR3 plays a positive rather than a negative role in DNA replication, cell transformation, and the expression of the minichromosome maintenance (MCM)2-7 family of DNA replication factors. These features are a paradigm shift in RBR gene function and appear to be unique within the RBR gene family. They suggest the existence in maize and related cereal crops of specific RBR/E2F-dependent pathways impinging on the cell cycle and development. RBR1 was down-regulated in transgenic endosperm using RNAi approaches. This resulted in the de-repression of a number of down-stream E2F targets, including RBR3, the MCM2-7 gene family, DNA methyltransferase (MET)1, CDKB;1, and the recently identified RBR4 gene. It also increased endosperm ploidy levels, stimulated the production of a larger

  14. Molecular Genetic Traits Influencing Maize Endosperm Development and Value: Closeout Report for DOE Grant DE-FG02-96ER20242

    Energy Technology Data Exchange (ETDEWEB)

    Brian A. Larkins

    2012-09-12

    Development of the endosperm in cereal grasses entails different phases characterized by cell division, endoreduplication, accumulation of storage metabolites and cell death, which need to be carried out in an orderly fashion. While correct regulation of the cell cycle plays an essential role in endosperm development, the key regulatory factors and how the cell cycle interfaces with other pathways in this developmental context are largely unknown. We investigated the cyclin-dependent kinase (CDK)-retinoblastoma pathway and how it controls the cell cycle and coordinates it with other processes during maize endosperm development. Retinoblastoma-related (RBR) proteins may be inactivated through CDK-mediated phosphorylation, but the identity of the responsible kinase in maize is unknown. We have previously shown that down-regulation of CDKA;1 severely inhibits the endoreduplication cell cycle and suggested that CDK may be an up-stream regulator of the retinoblastoma pathway. We discovered two types of maize RBR genes, RBR1 and RBR3, which differ in terms of structure, regulation and function. Phylogenetic analyses indicate that these genes may be distinctive features of the Poaceae. We found that RBR3 plays a positive rather than a negative role in DNA replication, cell transformation, and the expression of the minichromosome maintenance (MCM)2-7 family of DNA replication factors. These features are a paradigm shift in RBR gene function and appear to be unique within the RBR gene family. They suggest the existence in maize and related cereal crops of specific RBR/E2F-dependent pathways impinging on the cell cycle and development. RBR1 was down-regulated in transgenic endosperm using RNAi approaches. This resulted in the de-repression of a number of down-stream E2F targets, including RBR3, the MCM2-7 gene family, DNA methyltransferase (MET)1, CDKB;1, and the recently identified RBR4 gene. It also increased endosperm ploidy levels, stimulated the production of a larger

  15. Endosperm-specific co-expression of recombinant soybean ferritin and Aspergillus phytase in maize results in significant increases in the levels of bioavailable iron.

    Science.gov (United States)

    Drakakaki, Georgia; Marcel, Sylvain; Glahn, Raymond P; Lund, Elizabeth K; Pariagh, Sandra; Fischer, Rainer; Christou, Paul; Stoger, Eva

    2005-12-01

    We have generated transgenic maize plants expressing Aspergillus phytase either alone or in combination with the iron-binding protein ferritin. Our aim was to produce grains with increased amounts of bioavailable iron in the endosperm. Maize seeds expressing recombinant phytase showed enzymatic activities of up to 3 IU per gram of seed. In flour paste prepared from these seeds, up to 95% of the endogenous phytic acid was degraded, with a concomitant increase in the amount of available phosphate. In seeds expressing ferritin in addition to phytase, the total iron content was significantly increased. To evaluate the impact of the recombinant proteins on iron absorption in the human gut, we used an in vitro digestion/Caco-2 cell model. We found that phytase in the maize seeds was associated with increased cellular iron uptake, and that the rate of iron uptake correlated with the level of phytase expression regardless of the total iron content of the seeds. We also investigated iron bioavailability under more complex meal conditions by adding ascorbic acid, which promotes iron uptake, to all samples. This resulted in a further increase in iron absorption, but the effects of phytase and ascorbic acid were not additive. We conclude that the expression of recombinant ferritin and phytase could help to increase iron availability and enhance the absorption of iron, particularly in cereal-based diets that lack other nutritional components.

  16. Research on Laws of Starch Accumulation in Micro-endosperm Maize Kernel%微胚乳玉米籽粒中淀粉积累规律的研究

    Institute of Scientific and Technical Information of China (English)

    甘凤琼; 张亚平; 杨庆锋; 吴子恺

    2009-01-01

    [Objective] The experiment aimed to study laws of accumulation of starch in micro-endosperm maize kernel. [Method] The laws of accumulation of starch in maize embryo and OSK(the other section of a kernel except embryo) of MEM(micro-endosperm maize) were studied in this experiment by taking Gaoyou 115 maize as control. [Result] The starch accumulation speed of MEM embryo was slightly lower than that of Gaoyou115 and the starch accumulation speed of MEM OSK was far lower than that of Gaoyou 115, so the starch content of the whole kernel of Gaoyou 115 was 3.4 to 4.5 times as high as that of MEM during harvesting. The embryo starch weight ration of Gaoyou 115 maize during harvesting was only 3% to 4% while that of MEM was 16% to 22%. Moreover, starch accumulation speeds of different MEM materials were different and there were significant differences in starch content during harvesting among different MEM materials. [Conclusion] The starch accumulation in MEM was slow, and MEM has widely variation on starch accumulation.

  17. Nutritional property of endosperm starches from maize mutants: a parabolic relationship between slowly digestible starch and amylopectin fine structure.

    Science.gov (United States)

    Zhang, Genyi; Ao, Zihua; Hamaker, Bruce R

    2008-06-25

    The relationship between the slow digestion property of cooked maize starch and its molecular fine structure was investigated. Results of the in vitro Englyst assay showed a range of rapidly digestible starch (RDS) (70.1-98.9%), slowly digestible starch (SDS) (0.2-20.3%), and resistant starch (RS) (0.0-13.7%) among the tested maize mutant flour samples. Further analysis showed that amylose content was significantly correlated ( R = 0.763, P analysis revealed a parabolic relationship between SDS content and the weight ratio of amylopectin short chains (DP /= 13, named LF), which means amylopectin with a higher amount of either short chains or long chains can produce relatively high amounts of SDS. Furthermore, debranching analysis of the SDS materials from samples with the highest and lowest weight ratios of SF/LF (both had a high amount SDS) showed significantly different profiles, indicating there is not a uniform molecular structure for SDS. Thus, genetic mutants of maize samples have a good potential to provide raw starch materials of high nutritional quality. An additional finding showed that a simple and comparably high-throughput technique of Rapid Visco-Analyzer (RVA) can be used to screen genetic mutants on the basis of their RVA profiles.

  18. Relationship between endosperm cell and activities of key enzymes for starch in maize with different plant types%不同株型玉米籽粒胚乳细胞与淀粉合成关键酶活性分析

    Institute of Scientific and Technical Information of China (English)

    谷岩; 胡文河; 王思远; 梁煊赫; 何文安; 孙明春; 吴春胜

    2011-01-01

    【Objective】 The proliferation process of endosperm cell and its relationship with activities of key enzymes for starch were studied.【Method】 The upright maize varieties Xianyu 335 and Zhengdan 958 and the common maize varieties Changcheng 799 and Nongda 364 were chosen as the expeiriment material.Central kernels were collected after the pollination stage,endosperm cell number,kernel weight,starch content,activities of key enzymes for starch were determined,and the relationship was analyzed.【Result】 During the later grain-filling period,key enzymes:(ADPG,UDPG,SSS and GBSS)for starch of Xianyu 335 were higher than other three varieties.And the endosperm cell number,starch content,grain weight of Xianyu 335 and Zhengdan 958 were higher than Changcheng 799 and Nongda 364.The endosperm cell number had significantly positive correlation with grain weight,starch content and the enzyme activities for starch.【Conclusion】 The results here suggested that grain sink strength and activities were the main factors responsible for starch accumulation in maize.The higher endosperm cell numbers and key enzymes for starch were very important for the high yield of maize.%【目的】研究不同类型玉米品种籽粒胚乳细胞增殖与籽粒充实期淀粉合成关键酶活性的关系。【方法】以紧凑型玉米品种(先玉335和郑单958)和平展型玉米品种(长城799和农大364)为试验材料,于授粉后不同时间取果穗中部籽粒,测定胚乳细胞数、单粒质量、淀粉含量、腺苷二磷酸葡萄糖焦磷酸化酶(ADPG)、尿苷二磷酸葡萄糖焦磷酸化酶(UDPG)活性、可溶性淀粉合成酶(SSS)和束缚态淀粉合成酶(GBSS)活性,研究不同玉米品种籽粒胚乳细胞增殖动态和籽粒淀粉合成关键酶活性的关系。【结果】在灌浆中后期,先玉335籽粒淀粉合

  19. Feruloylated arabinoxylans are oxidatively cross-linked by extracellular maize peroxidase but not by horseradish peroxidase.

    Science.gov (United States)

    Burr, Sally J; Fry, Stephen C

    2009-09-01

    Covalent cross-linking of soluble extracellular arabinoxylans in living maize cultures, which models the cross-linking of wall-bound arabinoxylans, is due to oxidation of feruloyl esters to oligoferuloyl esters and ethers. The oxidizing system responsible could be H2O2/peroxidase, O2/laccase, or reactive oxygen species acting non-enzymically. To distinguish these possibilities, we studied arabinoxylan cross-linking in vivo and in vitro. In living cultures, exogenous, soluble, extracellular, feruloylated [pentosyl-3H]arabinoxylans underwent cross-linking, beginning abruptly 8 d after sub-culture. Cross-linking was suppressed by iodide, an H2O2 scavenger, indicating dependence on endogenous H2O2. However, exogenous H2O2 did not cause precocious cross-linking, despite the constant presence of endogenous peroxidases, suggesting that younger cultures contained natural cross-linking inhibitors. Dialysed culture-filtrates cross-linked [3H]arabinoxylans in vitro only if H2O2 was also added, indicating a peroxidase requirement. This cross-linking was highly ionic-strength-dependent. The peroxidases responsible were heat-labile, although relatively heat-stable peroxidases (assayed on o-dianisidine) were also present. Surprisingly, added horseradish peroxidase, even after heat-denaturation, blocked the arabinoxylan-cross-linking action of maize peroxidases, suggesting that the horseradish protein was a competing substrate for [3H]arabinoxylan coupling. In conclusion, we show for the first time that cross-linking of extracellular arabinoxylan in living maize cultures is an action of apoplastic peroxidases, some of whose unusual properties we report.

  20. Feruloylated Arabinoxylans Are Oxidatively Cross-Linked by Extracellular Maize Peroxidase but Not by Horseradish Peroxidase

    Institute of Scientific and Technical Information of China (English)

    Sally J. Burr; Stephen C. Fry

    2009-01-01

    Covalent cross-linking of soluble extraceUular arabinoxylans in living maize cultures, which models the cross-linking of wall-bound arabinoxylans, is due to oxidation of feruloyl esters to oligoferuloyl esters and ethers. The oxidizing system responsible could be H_2O_2/peroxidase, O_2/laccase, or reactive oxygen species acting non-enzymically. To distinguish these possibilities, we studied arabinoxylan cross-linking in vivo and in vitro. In living cultures, exogenous, soluble, extra-cellular, feruloylated [pentosyl-~3H]arabinoxylans underwent cross-linking, beginning abruptly 8 d after sub-culture. Cross-linking was suppressed by iodide, an H_2O_2 scavenger, indicating dependence on endogenous H2O2. However, exogenous H_2O_2 did not cause precocious cross-linking, despite the constant presence of endogenous peroxidases, suggesting that younger cultures contained natural cross-linking inhibitors. Dialysed culture-filtrates cross-linked [~3H]arabinoxylans in vitro only if H_20_2 was also added, indicating a peroxiclase requirement. This cross-linking was highly ionic-strength-dependent. The peroxidases responsible were heat-labile, although relatively heat-stable peroxidases (assayed on o-dianisidine) were also present, Surprisingly, added horseradish peroxidase, even after heat-denaturation, blocked the arabinoxylan-cross-linking action of maize peroxidases, suggesting that the horseradish protein was a competing substrate for [~3H]arabino-xylan coupling. In conclusion, we show for the first time that cross-linking of extracellular arabinoxylan in living maize cultures is an action of apoplastic peroxidases, some of whose unusual properties we report.

  1. Diurnal oscillation of SBE expression in sorghum endosperm

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Chuanxin; Mutisya, J.; Rosenquist, S.; Baguma, Y.; Jansson, C.

    2009-01-15

    Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum was cloned and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was expressed also in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 days after pollination. This is different from barley and maize where SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle.

  2. The Maize Viviparous8 locus, encoding a putative ALTERED MERISTEM PROGRAM1-like peptidase, regulates abscisic acid accumulation and coordinates embryo and endosperm development.

    Science.gov (United States)

    Suzuki, Masaharu; Latshaw, Susan; Sato, Yutaka; Settles, A Mark; Koch, Karen E; Hannah, L Curtis; Kojima, Mikiko; Sakakibara, Hitoshi; McCarty, Donald R

    2008-03-01

    We describe a mutant of Zea mays isolated from a W22 inbred transposon population, widow's peak mutant1 (wpk1), with an altered pattern of anthocyanin synthesis and aleurone cell differentiation in endosperm. In addition, a failure of the developing mutant embryo to form leaf initials is associated with decreased expression of a subset of meristem regulatory genes that includes Abphyl1 and Td1. We show that the viviparous8 (vp8) mutant has a similar pleiotropic phenotype in the W22 inbred background in contrast to the viviparous embryo phenotype exhibited in the standard genetic background, and we confirmed that wpk1 is allelic to vp8. Further genetic analysis revealed that the standard vp8 stock contains an unlinked, partially dominant suppressor of the vp8 mutation that is not present in W22. Consistent with the early-onset viviparous phenotype of vp8, expression of several embryonic regulators, including LEC1/B3 domain transcription factors, was reduced in the mutant embryo. Moreover, reduced abscisic acid (ABA) content of vp8/wpk1 embryos was correlated with altered regulation of ABA biosynthesis, as well as ABA catabolic pathways. The ABA biosynthetic gene Vp14 was down-regulated in the nonsuppressed background, whereas the ZmABA8'oxA1a ABA 8'-hydroxylase gene was strongly up-regulated in both genetic backgrounds. Molecular analysis revealed that Vp8 encodes a putative peptidase closely related to Arabidopsis thaliana ALTERED MERISTEM PROGRAM1. Because the Vp8 regulates meristem development as well as seed maturation processes, including ABA accumulation, we propose that VP8 is required for synthesis of an unidentified signal that integrates meristem and embryo formation in seeds.

  3. The Maize Viviparous8 Locus, Encoding a Putative ALTERED MERISTEM PROGRAM1-Like Peptidase, Regulates Abscisic Acid Accumulation and Coordinates Embryo and Endosperm Development1[W

    Science.gov (United States)

    Suzuki, Masaharu; Latshaw, Susan; Sato, Yutaka; Settles, A. Mark; Koch, Karen E.; Hannah, L. Curtis; Kojima, Mikiko; Sakakibara, Hitoshi; McCarty, Donald R.

    2008-01-01

    We describe a mutant of Zea mays isolated from a W22 inbred transposon population, widow's peak mutant1 (wpk1), with an altered pattern of anthocyanin synthesis and aleurone cell differentiation in endosperm. In addition, a failure of the developing mutant embryo to form leaf initials is associated with decreased expression of a subset of meristem regulatory genes that includes Abphyl1 and Td1. We show that the viviparous8 (vp8) mutant has a similar pleiotropic phenotype in the W22 inbred background in contrast to the viviparous embryo phenotype exhibited in the standard genetic background, and we confirmed that wpk1 is allelic to vp8. Further genetic analysis revealed that the standard vp8 stock contains an unlinked, partially dominant suppressor of the vp8 mutation that is not present in W22. Consistent with the early-onset viviparous phenotype of vp8, expression of several embryonic regulators, including LEC1/B3 domain transcription factors, was reduced in the mutant embryo. Moreover, reduced abscisic acid (ABA) content of vp8/wpk1 embryos was correlated with altered regulation of ABA biosynthesis, as well as ABA catabolic pathways. The ABA biosynthetic gene Vp14 was down-regulated in the nonsuppressed background, whereas the ZmABA8′oxA1a ABA 8′-hydroxylase gene was strongly up-regulated in both genetic backgrounds. Molecular analysis revealed that Vp8 encodes a putative peptidase closely related to Arabidopsis thaliana ALTERED MERISTEM PROGRAM1. Because the Vp8 regulates meristem development as well as seed maturation processes, including ABA accumulation, we propose that VP8 is required for synthesis of an unidentified signal that integrates meristem and embryo formation in seeds. PMID:18203869

  4. Fermentation of the endosperm cell walls of monocotyledon and dicotyledon plant species: The relationship between cell wall characteristics and fermentability

    NARCIS (Netherlands)

    Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.

    2000-01-01

    Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of

  5. Fermentation of the endosperm cell walls of monocotyledon and dicotyledon plant species: The relationship between cell wall characteristics and fermentability

    NARCIS (Netherlands)

    Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.

    2000-01-01

    Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of th

  6. Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection.

    Science.gov (United States)

    Zhu, Min; Chen, Yuting; Ding, Xin Shun; Webb, Stephen L; Zhou, Tao; Nelson, Richard S; Fan, Zaifeng

    2014-09-01

    The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  7. Covalent cross-linking of cell-wall polysaccharides through esterified diferulates as a maize resistance mechanism against corn borers.

    Science.gov (United States)

    Barros-Rios, Jaime; Santiago, Rogelio; Jung, Hans-Joachim G; Malvar, Rosa A

    2015-03-04

    There is strong evidence to suggest that cross-linking of cell-wall polymers through ester-linked diferulates has a key role in plant resistance to pests; however, direct experimentation to provide conclusive proof is lacking. This study presents an evaluation of the damage caused by two corn borer species on six maize populations particularly selected for divergent diferulate concentrations in pith stem tissues. Maize populations selected for high total diferulate concentration had 31% higher diferulates than those selected for low diferulates. Stem tunneling by corn borer species was 29% greater in the population with the lowest diferulates than in the population with the highest diferulates (31.7 versus 22.6 cm), whereas total diferulate concentration was negatively correlated with stem tunneling by corn borers. Moreover, orthogonal contrasts between groups of populations evaluated showed that larvae fed in laboratory bioassays on pith stem tissues from maize populations with higher diferulates had 30-40% lower weight than larvae fed on the same tissues from maize populations with lower diferulates. This is the first report that shows a direct relationship between diferulate deposition in maize cell walls and corn borer resistance. Current findings will help to develop adapted maize varieties with an acceptable level of resistance against borers and be useful in special kinds of agriculture, such as organic farming.

  8. Surface position, not signaling from surrounding maternal tissues, specifies aleurone epidermal cell fate in maize.

    Science.gov (United States)

    Gruis, Darren Fred; Guo, Hena; Selinger, David; Tian, Qing; Olsen, Odd-Arne

    2006-07-01

    Maize (Zea mays) endosperm consists of an epidermal-like surface layer of aleurone cells, an underlying body of starchy endosperm cells, and a basal layer of transfer cells. To determine whether surrounding maternal tissues perform a role in specifying endosperm cell fates, a maize endosperm organ culture technique was established whereby the developing endosperm is completely removed from surrounding maternal tissues. Using cell type-specific fluorescence markers, we show that aleurone cell fate specification occurs exclusively in response to surface position and does not require specific, continued maternal signal input. The starchy endosperm and aleurone cell fates are freely interchangeable throughout the lifespan of the endosperm, with internalized aleurone cells converting to starchy endosperm cells and with starchy endosperm cells that become positioned at the surface converting to aleurone cells. In contrast to aleurone and starchy endosperm cells, transfer cells fail to develop in in vitro-grown endosperm, supporting earlier indications that maternal tissue interaction is required to fully differentiate this cell type. Several parameters confirm that the maize endosperm organ cultures described herein retain the main developmental features of in planta endosperm, including fidelity of aleurone mutant phenotypes, temporal and spatial control of cell type-specific fluorescent markers, specificity of cell type transcripts, and control of mitotic cell divisions.

  9. 玉米胚乳DNA的快速提取方法及其在wx基因分子标记辅助选择中的应用%A Rapid DNA Extraction Protocol from Endosperm and Its Applications in Marker-assisted Selection for wx Gene in Maize

    Institute of Scientific and Technical Information of China (English)

    彭勃; 赵晓雷; 付从贵; 张巧云; 王奕

    2014-01-01

    Extracting genomic DNA is one of the bottleneck steps for molecular breeding. In this study, a high throughput and rapid genomic DNA extraction protocol for maize, named as sucrose prep method, were developed. According to this method, 20~30 mg of endosperm cut from seed were suffered by 3 steps, i.e. grinding, heating and instantaneously centrifuging in batch, and then the genomic DNA template with robust PCR products were obtained. In addition, there are no significant difference for germination rates between endosperm sampled seeds and non-sampled control. Three genotypes with W xW x, W xwx and wxwx identified by genotyping endosperm DNA were in completely accordance with the corresponding phenotypes in 190 F2 individuals. Therefore, endosperm DNA extracted through the Sucrose prep method was a simple, rapid and low cost method, and especially suitable for the application in high throughput marker-assisted selection.%模板DNA的制备是制约分子育种效率的瓶颈步骤之一。本研究介绍一种高通量快速的玉米基因组DNA提取方法,即蔗糖提取液法。该方法切取20~30 mg玉米种子胚乳,通过批量化研磨、加热和瞬时离心3个步骤,即可获得稳健PCR扩增的模板DNA,并且在光温培养箱条件下切取部分胚乳的剩余种子与对照完整种子发芽率无显著差异。通过蔗糖提取液法提取192粒F2种子胚乳DNA,鉴定W xW x、W xwx和wxwx 3种基因型与表型鉴定结果相一致。蔗糖提取液法提取胚乳DNA简单、快速、成本低廉,可有效用于高通量分子标记辅助选择。

  10. Divergent selection for ester-linked diferulates in maize pith stalk tissues. Effects on cell wall composition and degradability.

    Science.gov (United States)

    Barros-Rios, Jaime; Malvar, Rosa A; Jung, Hans-Joachim G; Bunzel, Mirko; Santiago, Rogelio

    2012-11-01

    Cross-linking of grass cell wall components through diferulates (DFAs) has a marked impact on cell wall properties. However, results of genetic selection for DFA concentration have not been reported for any grass species. We report here the results of direct selection for ester-linked DFA concentration in maize stalk pith tissues and the associated changes in cell wall composition and biodegradability. After two cycles of divergent selection, maize populations selected for higher total DFA (DFAT) content (CHs) had 16% higher DFAT concentrations than populations selected for lower DFAT content (CLs). These significant DFA concentration gains suggest that DFA deposition in maize pith parenchyma cell walls is a highly heritable trait that is genetically regulated and can be modified trough conventional breeding. Maize populations selected for higher DFAT had 13% less glucose and 10% lower total cell wall concentration than CLs, suggesting that increased cross-linking of feruloylated arabinoxylans results in repacking of the matrix and possibly in thinner and firmer cell walls. Divergent selection affected esterified DFAT and monomeric ferulate ether cross link concentrations differently, supporting the hypothesis that the biosynthesis of these cell wall components are separately regulated. As expected, a more higher DFA ester cross-coupled arabinoxylan network had an effect on rumen cell wall degradability (CLs showed 12% higher 24-h total polysaccharide degradability than CHs). Interestingly, 8-8-coupled DFAs, previously associated with cell wall strength, were the best predictors of pith cell wall degradability (negative impact). Thus, further research on the involvement of these specific DFA regioisomers in limiting cell wall biodegradability is encouraged.

  11. Endosperm Development in Autotetraploid Rice

    Institute of Scientific and Technical Information of China (English)

    WANG Lan; LIU Xiang-dong; LU Yong-gen; FENG Jiu-huan; XU Xue-bin; XU Shi-xiong (S.Y.Zee)

    2005-01-01

    By using the laser scanning confocal microscope and plastic (Leica 7022 historesin embedding kit) semi-thin sectioningtechnique, comparative studies on the development of endosperm were carried out between autotetraploid and diploid rices. Aboutone third of the ovaries in the autotetraploid showed normal endosperm development as those in the diploid. In these ovaries, one ofthe polar nuclei would fuse with the sperm nucleus, and the primary endosperm nucleus formed and underwent the first division in 4hours after pollination; the anticlinal wall began to grow centripetally between the free nuclei starting from the wall ingrowths of theembryo sac near the micropylar end, and some of the phragmoplasts formed transformed into periclinal walls. In addition, some of thecell wall situated in the middle of the endosperm appeared to originate from phragmoplasts, whereas others seemed to developrandomly without the obvious formation of phragmoplasts. Cellulose began to accumulate in the wall of aleurone cell layer at 6 daysafter pollination. The cellulose wall of the cells of the aleurone cell layer appeared to have completely formed within 7 to 8 days afterpollination. On the other hand, about two thirds of the ovaries in the autotetraploid showed abnormality in endosperm developmentwith various types, such as non-fertilization, abnormal fertilization, endosperm development-delay and non-synchronization in thedevelopment of cellulose wall of cells of the aleurone layer. These abnormalities usually resulted in decreased seed setting inautotetraploid rice.

  12. The maize ALDH protein superfamily: linking structural features to functional specificities

    Directory of Open Access Journals (Sweden)

    Seufferheld Manfredo J

    2010-12-01

    Full Text Available Abstract Background The completion of maize genome sequencing has resulted in the identification of a large number of uncharacterized genes. Gene annotation and functional characterization of gene products are important to uncover novel protein functionality. Results In this paper, we identify, and annotate members of all the maize aldehyde dehydrogenase (ALDH gene superfamily according to the revised nomenclature criteria developed by ALDH Gene Nomenclature Committee (AGNC. The maize genome contains 24 unique ALDH sequences encoding members of ten ALDH protein families including the previously identified male fertility restoration RF2A gene, which encodes a member of mitochondrial class 2 ALDHs. Using computational modeling analysis we report here the identification, the physico-chemical properties, and the amino acid residue analysis of a novel tunnel like cavity exclusively found in the maize sterility restorer protein, RF2A/ALDH2B2 by which this protein is suggested to bind variably long chain molecular ligands and/or potentially harmful molecules. Conclusions Our finding indicates that maize ALDH superfamily is the most expanded of plant ALDHs ever characterized, and the mitochondrial maize RF2A/ALDH2B2 is the only plant ALDH that harbors a newly defined pocket/cavity with suggested functional specificity.

  13. Linking Maize Farmers to Market: A Case Study of Private Extension ...

    African Journals Online (AJOL)

    E M IGBOKWE

    sourcing farm input and marketing as the critical extension needs of farmers in. Telfairia ... does the level of technology adoption and productivity, resulting into a low level equilibrium .... farmers were engaged on contract to produce SWAN 1 variety of maize exclusively ..... Facilitating multi-stakeholder and institutional.

  14. Testing the link between genome size and growth rate in maize

    Directory of Open Access Journals (Sweden)

    Maud I. Tenaillon

    2016-09-01

    Full Text Available Little is known about the factors driving within species Genome Size (GS variation. GS may be shaped indirectly by natural selection on development and adaptative traits. Because GS variation is particularly pronounced in maize, we have sampled 83 maize inbred lines from three well described genetic groups adapted to contrasted climate conditions: inbreds of tropical origin, Flint inbreds grown in temperate climates, and Dent inbreds distributed in the Corn Belt. As a proxy for growth rate, we measured the Leaf Elongation Rate maximum during nighttime (LERmax as well as GS in all inbred lines. In addition we combined available and new nucleotide polymorphism data at 29,090 sites to characterize the genetic structure of our panel. We found significant variation for both LERmax and GS among groups defined by our genetic structuring. Tropicals displayed larger GS than Flints while Dents exhibited intermediate values. LERmax followed the opposite trend with greater growth rate in Flints than in Tropicals. In other words, LERmax and GS exhibited a significantly negative correlation (r = − 0.27. However, this correlation was driven by among-group variation rather than within-group variation—it was no longer significant after controlling for structure and kinship among inbreds. Our results indicate that selection on GS may have accompanied ancient maize diffusion from its center of origin, with large DNA content excluded from temperate areas. Whether GS has been targeted by more intense selection during modern breeding within groups remains an open question.

  15. Interaction between maize seed and Aspergillus flavus

    Science.gov (United States)

    Aspergillus flavus is an opportunistic fungal pathogen that colonizes maize seeds and contaminates them with aflatoxin. The fungus is localized in the endosperm and aleurone. To investigate the plant microbe interaction, we conducted histological and molecular studies to characterize the internal co...

  16. Iron bioavailability of maize hemoglobin in a Caco-2 cell culture model.

    Science.gov (United States)

    Bodnar, Anastasia L; Proulx, Amy K; Scott, M Paul; Beavers, Alyssa; Reddy, Manju B

    2013-07-31

    Maize ( Zea mays ) is an important staple crop in many parts of the world but has low iron bioavailability, in part due to its high phytate content. Hemoglobin is a form of iron that is highly bioavailable, and its bioavailability is not inhibited by phytate. It was hypothesized that maize hemoglobin is a highly bioavailable iron source and that biofortification of maize with iron can be accomplished by overexpression of maize globin in the endosperm. Maize was transformed with a gene construct encoding a translational fusion of maize globin and green fluorescent protein under transcriptional control of the maize 27 kDa γ-zein promoter. Iron bioavailability of maize hemoglobin produced in Escherichia coli and of stably transformed seeds expressing the maize globin-GFP fusion was determined using an in vitro Caco-2 cell culture model. Maize flour fortified with maize hemoglobin was found to have iron bioavailability that is not significantly different from that of flour fortified with ferrous sulfate or bovine hemoglobin but is significantly higher than unfortified flour. Transformed maize grain expressing maize globin was found to have iron bioavailability similar to that of untransformed seeds. These results suggest that maize globin produced in E. coli may be an effective iron fortificant, but overexpressing maize globin in maize endosperm may require a different strategy to increase bioavailable iron content in maize.

  17. 21 CFR 73.315 - Corn endosperm oil.

    Science.gov (United States)

    2010-04-01

    ... corn endosperm oil is a reddish-brown liquid composed chiefly of glycerides, fatty acids, sitosterols.... (b) Specifications. Corn endosperm oil conforms to the following specifications: Total fatty...

  18. Quality protein maize: QPM

    Directory of Open Access Journals (Sweden)

    Ignjatović-Micić Dragana

    2008-01-01

    Full Text Available Quality protein maize (QPM contains the opaque-2 gene along with numerous modifiers for kernel hardness. Therefore, QPM is maize with high nutritive value of endosperm protein, with substantially higher content of two essential amino acids - lysine and tryptophan, and with good agronomical performances. Although QPM was developed primarily for utilization in the regions where, because of poverty, maize is the main staple food, it has many advantages for production and consumption in other parts of the world, too. QPM can be used for production of conventional and new animal feed, as well as for human nurture. As the rate of animal weight gain is doubled with QPM and portion viability is better, a part of normal maize production could be available for other purposes, such as, for example, ethanol production. Thus, breeding QPM is set as a challenge to produce high quality protein maize with high yield and other important agronomical traits, especially with today's food and feed demands and significance of energy crisis.

  19. Aleurone cell identity is suppressed following connation in maize kernels.

    Science.gov (United States)

    Geisler-Lee, Jane; Gallie, Daniel R

    2005-09-01

    Expression of the cytokinin-synthesizing isopentenyl transferase enzyme under the control of the Arabidopsis (Arabidopsis thaliana) SAG12 senescence-inducible promoter reverses the normal abortion of the lower floret from a maize (Zea mays) spikelet. Following pollination, the upper and lower floret pistils fuse, producing a connated kernel with two genetically distinct embryos and the endosperms fused along their abgerminal face. Therefore, ectopic synthesis of cytokinin was used to position two independent endosperms within a connated kernel to determine how the fused endosperm would affect the development of the two aleurone layers along the fusion plane. Examination of the connated kernel revealed that aleurone cells were present for only a short distance along the fusion plane whereas starchy endosperm cells were present along most of the remainder of the fusion plane, suggesting that aleurone development is suppressed when positioned between independent starchy endosperms. Sporadic aleurone cells along the fusion plane were observed and may have arisen from late or imperfect fusion of the endosperms of the connated kernel, supporting the observation that a peripheral position at the surface of the endosperm and not proximity to maternal tissues such as the testa and pericarp are important for aleurone development. Aleurone mosaicism was observed in the crown region of nonconnated SAG12-isopentenyl transferase kernels, suggesting that cytokinin can also affect aleurone development.

  20. Inducement and identification of an endosperm mutant in maize

    African Journals Online (AJOL)

    ajl yemi

    2011-11-30

    Nov 30, 2011 ... “super sweet” phenotype were derived from the mutated offspring. ... characteristics and distinguished molecular mechanism to the previous mutants of gene sh2, these three mutant lines are ...... Physical association of starch biosynthetic ... reduced seedling mutant in oilseed rape, Brassica napus, for.

  1. A population of deletion mutants and an integrated mapping and Exome-seq pipeline for gene discovery in maize

    Science.gov (United States)

    To better understand maize endosperm filling and maturation, we developed a novel functional genomics platform that combined Bulked Segregant RNA and Exome sequencing (BSREx-seq) to map causative mutations and identify candidate genes within mapping intervals. Using gamma-irradiation of B73 maize to...

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

    Directory of Open Access Journals (Sweden)

    Carlo F. Moro

    2015-08-01

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

  3. Processing maize flour and corn meal food products.

    Science.gov (United States)

    Gwirtz, Jeffrey A; Garcia-Casal, Maria Nieves

    2014-04-01

    Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathways from raw grain to the consumer final product, which entail changes in nutrient composition. Dry maize mechanical processing creates whole or fractionated products, separated by anatomical features such as bran, germ, and endosperm. Wet maize processing separates by chemical compound classification such as starch and protein. Various industrial processes, including whole grain, dry milling fractionation, and nixtamalization, are described. Vitamin and mineral losses during processing are identified and the nutritional impacts outlined. Also discussed are the vitamin and mineral contents of corn.

  4. Processing maize flour and corn meal food products

    Science.gov (United States)

    Gwirtz, Jeffrey A; Garcia-Casal, Maria Nieves

    2014-01-01

    Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathways from raw grain to the consumer final product, which entail changes in nutrient composition. Dry maize mechanical processing creates whole or fractionated products, separated by anatomical features such as bran, germ, and endosperm. Wet maize processing separates by chemical compound classification such as starch and protein. Various industrial processes, including whole grain, dry milling fractionation, and nixtamalization, are described. Vitamin and mineral losses during processing are identified and the nutritional impacts outlined. Also discussed are the vitamin and mineral contents of corn. PMID:24329576

  5. Replication of DNA during barley endosperm development

    DEFF Research Database (Denmark)

    Giese, H.

    1992-01-01

    The incorporation of [6-H-3]-thymidine into DNA of developing barley end sperm was examined by autoradiography of cross sections of seeds and DNA analysis. The majority of nuclear divisions took place in the very young endosperm, but as late as 25 days after anthesis there was evidence for DNA...... replication. The DNA content of the endosperm increases during development and in response to nitrogen application in parallel to the storage protein synthesis profile. The hordein genes were hypersensitive to DNase I treatment throughout development....

  6. Rice caryopsis development II:Dynamic changes in the endosperm

    Institute of Scientific and Technical Information of China (English)

    Xiaoba Wu; Jinxin Liu; Dongqi Li; Chun-Ming Liu

    2016-01-01

    The rice endosperm plays crucial roles in nourishing the embryo during embryogenesis and seed germination. Although previous studies have provided the general information about rice endosperm, a systematic investigation throughout the entire endosperm developmental process is still lacking. In this study, we examined in detail rice endosperm development on a daily basis throughout the 30-day period of post-fertilization development. We observed that coenocytic nuclear division occurred in the first 2 days after pollination (DAP), cellularization occurred between 3 and 5 DAP, differentiation of the aleurone and starchy endosperm occurred between 6 and 9 DAP, and accumulation of storage products occurred concurrently with the aleurone/starchy endosperm differentiation from 6 DAP onwards and was accomplished by 21 DAP. Changes in cytoplasmic membrane permeability, possibly caused by programmed cell death, were observed in the central region of the starchy endosperm at 8 DAP, and expanded to the whole starchy endosperm at 21 DAP when the aleurone is the only living component in the endosperm. Further, we observed that a distinct multi-layered dorsal aleurone formed near the dorsal vascular bundle, while the single- or occasionally two-cell layered aleurone was located in the lateral and ventral positions of endosperm. Our results provide in detail the dynamic changes in mitotic divisions, cellularization, cell differentiation, storage product accumulation, and programmed cell death that occur during rice endosperm development.

  7. Rice caryopsis development II: Dynamic changes in the endosperm.

    Science.gov (United States)

    Wu, Xiaoba; Liu, Jinxin; Li, Dongqi; Liu, Chun-Ming

    2016-09-01

    The rice endosperm plays crucial roles in nourishing the embryo during embryogenesis and seed germination. Although previous studies have provided the general information about rice endosperm, a systematic investigation throughout the entire endosperm developmental process is still lacking. In this study, we examined in detail rice endosperm development on a daily basis throughout the 30-day period of post-fertilization development. We observed that coenocytic nuclear division occurred in the first 2 days after pollination (DAP), cellularization occurred between 3 and 5 DAP, differentiation of the aleurone and starchy endosperm occurred between 6 and 9 DAP, and accumulation of storage products occurred concurrently with the aleurone/starchy endosperm differentiation from 6 DAP onwards and was accomplished by 21 DAP. Changes in cytoplasmic membrane permeability, possibly caused by programmed cell death, were observed in the central region of the starchy endosperm at 8 DAP, and expanded to the whole starchy endosperm at 21 DAP when the aleurone is the only living component in the endosperm. Further, we observed that a distinct multi-layered dorsal aleurone formed near the dorsal vascular bundle, while the single- or occasionally two-cell layered aleurone was located in the lateral and ventral positions of endosperm. Our results provide in detail the dynamic changes in mitotic divisions, cellularization, cell differentiation, storage product accumulation, and programmed cell death that occur during rice endosperm development.

  8. Genome-wide screen of genes imprinted in sorghum endosperm, and the roles of allelic differential cytosine methylation.

    Science.gov (United States)

    Zhang, Meishan; Li, Ning; He, Wenan; Zhang, Huakun; Yang, Wei; Liu, Bao

    2016-02-01

    Imprinting is an epigenetic phenomenon referring to allele-biased expression of certain genes depending on their parent of origin. Accumulated evidence suggests that, while imprinting is a conserved mechanism across kingdoms, the identities of the imprinted genes are largely species-specific. Using deep RNA sequencing of endosperm 14 days after pollination in sorghum, 5683 genes (29.27% of the total 19 418 expressed genes) were found to harbor diagnostic single nucleotide polymorphisms between two parental lines. The analysis of parent-of-origin expression patterns in the endosperm of a pair of reciprocal F1 hybrids between the two sorghum lines led to identification of 101 genes with ≥ fivefold allelic expression difference in both hybrids, including 85 maternal expressed genes (MEGs) and 16 paternal expressed genes (PEGs). Thirty of these genes were previously identified as imprinted in endosperm of maize (Zea mays), rice (Oryza sativa) or Arabidopsis, while the remaining 71 genes are sorghum-specific imprinted genes relative to these three plant species. Allele-biased expression of virtually all of the 14 tested imprinted genes (nine MEGs and five PEGs) was validated by pyrosequencing using independent sources of RNA from various developmental stages and dissected parts of endosperm. Forty-six imprinted genes (30 MEGs and 16 PEGs) were assayed by quantitative RT-PCR, and the majority of them showed endosperm-specific or preferential expression relative to embryo and other tissues. DNA methylation analysis of the 5' upstream region and gene body for seven imprinted genes indicated that, while three of the four PEGs were associated with hypomethylation of maternal alleles, no MEG was associated with allele-differential methylation.

  9. The Identification of Maize and Arabidopsis Type I FLAVONE SYNTHASEs Links Flavones with Hormones and Biotic Interactions.

    Science.gov (United States)

    Falcone Ferreyra, María Lorena; Emiliani, Julia; Rodriguez, Eduardo José; Campos-Bermudez, Valeria Alina; Grotewold, Erich; Casati, Paula

    2015-10-01

    Flavones are a major group of flavonoids with diverse functions and are extensively distributed in land plants. There are two different classes of FLAVONE SYNTHASE (FNS) enzymes that catalyze the conversion of the flavanones into flavones. The FNSI class comprises soluble Fe(2+)/2-oxoglutarate-dependent dioxygenases, and FNSII enzymes are oxygen- and NADPH-dependent cytochrome P450 membrane-bound monooxygenases. Here, we describe the identification and characterization of FNSI enzymes from maize (Zea mays) and Arabidopsis (Arabidopsis thaliana). In maize, ZmFNSI-1 is expressed at significantly higher levels in silks and pericarps expressing the 3-deoxy flavonoid R2R3-MYB regulator P1, suggesting that ZmFNSI-1 could be the main enzyme for the synthesis of flavone O-glycosides. We also show here that DOWNY MILDEW RESISTANT6 (AtDMR6), the Arabidopsis homologous enzyme to ZmFNSI-1, has FNSI activity. While dmr6 mutants show loss of susceptibility to Pseudomonas syringae, transgenic dmr6 plants expressing ZmFNSI-1 show similar susceptibility to wild-type plants, demonstrating that ZmFNSI-1 can complement the mutant phenotype. AtDMR6 expression analysis showed a tissue- and developmental stage-dependent pattern, with high expression in cauline and senescing leaves. Finally, we show that Arabidopsis cauline and senescing leaves accumulate apigenin, demonstrating that Arabidopsis plants have an FNSI activity involved in the biosynthesis of flavones. The results presented here also suggest cross talk between the flavone and salicylic acid pathways in Arabidopsis; in this way, pathogens would induce flavones to decrease salicylic acid and, hence, increase susceptibility.

  10. A new statistical method for mapping QTLs underlying endosperm traits

    Institute of Scientific and Technical Information of China (English)

    HU Zhiqiu; XU Chenwu

    2005-01-01

    Genetic expression for an endosperm trait in seeds of cereal crops may be controlled simultaneously by the triploid endosperm genotypes and the diploid maternal genotypes. However, current statistical methods for mapping quantitative trait loci (QTLs) underlying endosperm traits have not been effective in dealing with the putative maternal genetic effects. Combining the quantitative genetic model for diploid maternal traits with triploid endosperm traits, here we propose a new statistical method for mapping QTLs controlling endosperm traits with maternal genetic effects. This method applies the data set of both DNA molecular marker genotypes of each plant in segregation population and the quantitative observations of single endosperms in each plant to map QTL. The maximum likelihood method implemented via the expectation-maximization algorithm was used to the estimate parameters of a putative QTL. Since this method involves the maternal effect that may contribute to endosperm traits, it might be more congruent with the genetics of endosperm traits and more helpful to increasing the precision of QTL mapping. The simulation results show the proposed method provides accurate estimates of the QTL effects and locations with high statistical power.

  11. The functions of the endosperm during seed germination.

    Science.gov (United States)

    Yan, Dawei; Duermeyer, Lisza; Leoveanu, Catalina; Nambara, Eiji

    2014-09-01

    In angiosperms, a double fertilization event initiates the development of two distinct structures, the embryo and endosperm. The endosperm plays an important role in supporting embryonic growth by supplying nutrients, protecting the embryo and controlling embryo growth by acting as a mechanical barrier during seed development and germination. Its structure and function in the mature dry seed is divergent and specialized among different plant species. A subset of endospermic tissues are composed of living cells even after seed maturation, and play an active role in the regulation of seed germination. Transcriptome analysis has provided new insights into the regulatory functions of the endosperm during seed germination. It is well known that the embryo secretes signals to the endosperm to induce the degradation of the seed reserve and to promote endosperm weakening during germination. Recent advances in seed biology have shown that the endosperm is capable of sensing environmental signals, and can produce and secrete signals to regulate the growth of the embryo. Thus, germination is a systemic response that involves bidirectional interactions between the embryo and endosperm.

  12. Development of endosperm transfer cells in barley

    Directory of Open Access Journals (Sweden)

    Johannes eThiel

    2014-03-01

    Full Text Available Endosperm transfer cells (ETCs are positioned at the intersection of maternal and filial tissues in seeds of cereals and represent a bottleneck for apoplasmic transport of assimilates into the endosperm. Endosperm cellularization starts at the maternal-filial boundary and generates the highly specialized ETCs. During differentiation barley ETCs develop characteristic flange-like wall ingrowths to facilitate effective nutrient transfer. A comprehensive morphological analysis depicted distinct developmental time points in establishment of transfer cell morphology and revealed intracellular changes possibly associated with cell wall metabolism. Embedded inside the grain, ETCs are barely accessible by manual preparation. To get tissue-specific information about ETC specification and differentiation, laser microdissection(LM-based methods were used for transcript and metabolite profiling. Transcriptome analysis of ETCs at different developmental stages by microarrays indicated activated gene expression programs related to control of cell proliferation and cell shape, cell wall and carbohydrate metabolism reflecting the morphological changes during early ETC development. Transporter genes reveal distinct expression patterns suggesting a switch from active to passive modes of nutrient uptake with the onset of grain filling. Tissue-specific RNA-seq of the differentiating ETC region from the syncytial stage until functionality in nutrient transfer identified a high number of novel transcripts putatively involved in ETC differentiation. An essential role for two-component signaling (TCS pathways in transfer cell development of barley emerged from this analysis. Correlative data provide evidence for ABA and ethylene influences on ETC differentiation and hint at a crosstalk between hormone signal transduction and TCS phosphorelays. Collectively, the data expose a comprehensive view on ETC development, associated pathways and identified candidate genes for

  13. Application of two bicistronic systems involving 2A and IRES sequences to the biosynthesis of carotenoids in rice endosperm.

    Science.gov (United States)

    Ha, Sun-Hwa; Liang, Ying Shi; Jung, Harin; Ahn, Mi-Jeong; Suh, Seok-Cheol; Kweon, Soon-Jong; Kim, Dong-Hern; Kim, Young-Mi; Kim, Ju-Kon

    2010-10-01

    Coordination of multiple transgenes is essential for metabolic engineering of biosynthetic pathways. Here, we report the utilization of two bicistronic systems involving the 2A sequence from the foot-and-mouth disease virus and the internal ribosome entry site (IRES) sequence from the crucifer-infecting tobamovirus to the biosynthesis of carotenoids in rice endosperm. Two carotenoid biosynthetic genes, phytoene synthase (Psy) from Capsicum and carotene desaturase (CrtI) from Pantoea, were linked via either the synthetic 2A sequence that was optimized for rice codons or the IRES sequence under control of the rice globulin promoter, generating PAC (Psy-2A-CrtI) and PIC (Psy-IRES-CrtI) constructs, respectively. The transgenic endosperm of PAC rice had a more intense golden color than did PIC rice, demonstrating that 2A was more efficient than IRES in coordinating gene expression. The 2A and IRES constructs were equally effective in driving transgene transcription. However, immunoblot analysis of CRTI, a protein encoded by the downstream open reading frame of the bicistronic constructs, revealed that 2A was ninefold more effective than IRES in driving translation. The PAC endosperms accumulated an average of 1.3 μg/g of total carotenoids, which was ninefold higher than was observed for PIC endosperms. In particular, accumulation of β-carotene was much higher in PAC endosperms than in PIC endosperms. Collectively, these results demonstrate that both 2A and IRES systems can coordinate the expression of two biosynthetic genes, with the 2A system exhibiting greater efficiency. Thus, the 2A expression system described herein is an effective new tool for multigene stacking in crop biotechnology. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology and Blackwell Publishing Ltd.

  14. Seed filling in domesticated maize and rice depends on SWEET-mediated hexose transport.

    Science.gov (United States)

    Sosso, Davide; Luo, Dangping; Li, Qin-Bao; Sasse, Joelle; Yang, Jinliang; Gendrot, Ghislaine; Suzuki, Masaharu; Koch, Karen E; McCarty, Donald R; Chourey, Prem S; Rogowsky, Peter M; Ross-Ibarra, Jeffrey; Yang, Bing; Frommer, Wolf B

    2015-12-01

    Carbohydrate import into seeds directly determines seed size and must have been increased through domestication. However, evidence of the domestication of sugar translocation and the identities of seed-filling transporters have been elusive. Maize ZmSWEET4c, as opposed to its sucrose-transporting homologs, mediates transepithelial hexose transport across the basal endosperm transfer layer (BETL), the entry point of nutrients into the seed, and shows signatures indicative of selection during domestication. Mutants of both maize ZmSWEET4c and its rice ortholog OsSWEET4 are defective in seed filling, indicating that a lack of hexose transport at the BETL impairs further transfer of sugars imported from the maternal phloem. In both maize and rice, SWEET4 was likely recruited during domestication to enhance sugar import into the endosperm.

  15. Maize provitamin A carotenoids, current resources and future metabolic engineering challenges.

    Directory of Open Access Journals (Sweden)

    Eleanore T Wurtzel

    2012-02-01

    Full Text Available Vitamin A deficiency is a serious global health problem that can be alleviated by improved nutrition. Development of cereal crops with increased provitamin A carotenoids can provide a sustainable solution to eliminating vitamin A deficiency worldwide. Maize is a model for cereals and a major staple carbohydrate source. Here, we discuss maize carotenogenesis with regard to pathway regulation, available resources, and current knowledge for improving carotenoid content and levels of provitamin A carotenoids in edible maize endosperm. This knowledge will be applied to improve the nutritional composition of related Poaceae crops. We discuss opportunities and challenges for optimizing provitamin A carotenoid biofortification of cereal food crops.

  16. Soya beans and Maize : The effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics

    OpenAIRE

    Laar, van de, P.

    2000-01-01

    The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid production) of soya bean and maize cell walls was analysed, both in situ and in vitro. This analysis revealed that the physical structure of the cell wall (particle size and cell wall thickness) influences cell...

  17. Soya beans and maize : the effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics

    NARCIS (Netherlands)

    Laar, van H.

    2000-01-01

    The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid prod

  18. Soya beans and maize : the effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics

    NARCIS (Netherlands)

    Laar, van H.

    2000-01-01

    The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid

  19. Soya beans and Maize : The effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics

    NARCIS (Netherlands)

    Laar, van H.

    2000-01-01

    The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid production) o

  20. The thick aleurone1 mutant defines a negative regulation of maize aleurone fate that functions downstream of dek1

    Science.gov (United States)

    The maize aleurone layer occupies the single outermost layer of the endosperm. The dek1 gene is a central regulator required for aleurone cell fate specification. Dek1 mutants have pleiotropic phenotypes including lack of aleurone cells, aborted embryos, carotenoid deficiency and a soft, floury endo...

  1. Fast-Flowering Mini-Maize: Seed to Seed in 60 Days

    Science.gov (United States)

    McCaw, Morgan E.; Wallace, Jason G.; Albert, Patrice S.; Buckler, Edward S.; Birchler, James A.

    2016-01-01

    Two lines of Zea mays were developed as a short-generation model for maize. The Fast-Flowering Mini-Maize (FFMM) lines A and B are robust inbred lines with a significantly shorter generation time, much smaller stature, and better greenhouse adaptation than traditional maize varieties. Five generations a year are typical. FFMM is the result of a modified double-cross hybrid between four fast-flowering lines: Neuffer’s Early ACR (full color), Alexander’s Early Early Synthetic, Tom Thumb Popcorn, and Gaspe Flint, followed by selection for early flowering and desirable morphology throughout an 11-generation selfing regime. Lines A and B were derived from different progeny of the initial hybrid, and crosses between Mini-Maize A and B exhibit heterosis. The ancestry of each genomic region of Mini-Maize A and B was inferred from the four founder populations using genotyping by sequencing. Other genetic and genomic tools for these lines include karyotypes for both lines A and B, kernel genetic markers y1 (white endosperm) and R1-scm2 (purple endosperm and embryo) introgressed into Mini-Maize A, and ∼24× whole-genome resequencing data for Mini-Maize A. PMID:27440866

  2. The effects of calcium regulation of endosperm reserve protein ...

    African Journals Online (AJOL)

    Administrator

    2011-06-15

    Jun 15, 2011 ... The effects of steep liquor calcium ion on sorghum endosperm reserve protein mobilization were ... ularly calcium ion exerted a strong regulatory influence ... determined spectrophotometrically as ammonia using Nessler's.

  3. The seeds of Lotus japonicus lines transformed with sense, antisense, and sense/antisense galactomannan galactosyltransferase constructs have structurally altered galactomannans in their endosperm cell walls.

    Science.gov (United States)

    Edwards, Mary E; Choo, Tze-Siang; Dickson, Cathryn A; Scott, Catherine; Gidley, Michael J; Reid, J S Grant

    2004-03-01

    Galactomannan biosynthesis in legume seed endosperms involves two Golgi membrane-bound glycosyltransferases, mannan synthase and galactomannan galactosyltransferase (GMGT). GMGT specificity is an important factor regulating the distribution and amount of (1-->6)-alpha-galactose (Gal) substitution of the (1-->4)-beta-linked mannan backbone. The model legume Lotus japonicus is shown now to have endospermic seeds with endosperm cell walls that contain a high-Gal galactomannan (mannose [Man]/Gal = 1.2-1.3). Galactomannan biosynthesis in developing L. japonicus endosperms has been mapped, and a cDNA encoding a functional GMGT has been obtained from L. japonicus endosperms during galactomannan deposition. L. japonicus has been transformed with sense, antisense, and sense/antisense ("hairpin loop") constructs of the GMGT cDNA. Some of the sense, antisense, and sense/antisense transgenic lines exhibited galactomannans with altered (higher) Man/Gal values in their (T(1) generation) seeds, at frequencies that were consistent with posttranscriptional silencing of GMGT. For T(1) generation individuals, transgene inheritance was correlated with galactomannan composition and amount in the endosperm. All the azygous individuals had unchanged galactomannans, whereas those that had inherited a GMGT transgene exhibited a range of Man/Gal values, up to about 6 in some lines. For Man/Gal values up to 4, the results were consistent with lowered Gal substitution of a constant amount of mannan backbone. Further lowering of Gal substitution was accompanied by a slight decrease in the amount of mannan backbone. Microsomal membranes prepared from the developing T(2) generation endosperms of transgenic lines showed reduced GMGT activity relative to mannan synthase. The results demonstrate structural modification of a plant cell wall polysaccharide by designed regulation of a Golgi-bound glycosyltransferase.

  4. Effect of processing conditions on phytic acid, calcium, iron, and zinc contents of lime-cooked maize.

    Science.gov (United States)

    Bressani, Ricardo; Turcios, Juan Carlos; Colmenares de Ruiz, Ana Silvia; de Palomo, Patricia Palocios

    2004-03-10

    Tortillas are made by cooking maize in a lime solution during variable times and temperatures, steeping the grain for up to 12 h, washing and grinding it to a fine dough, and cooking portions as flat cakes for up to 6 min. The effects of the main processing steps on the chemical composition, nutritive value, and functional and physicochemical characteristics have been areas of research. The present work evaluates the effect of lime concentration (0, 1.2, 2.4, and 3.6%) and cooking times (45, 60, and 75 min) on phytic acid retention of whole maize, its endosperm, and germ, as well as on the content of calcium, iron, and zinc on the same samples. The effects of steeping time and temperature and steeping medium on the phytic acid of lime-cooked maize were also studied. Finally, phytic acid changes from raw maize to tortilla were also measured. The results indicated that lime concentration and cooking time reduce phytic acid content in whole grain (17.4%), in endosperm (45.8%), and in germ (17.0%). Statistical analyses suggested higher phytic acid loss with 1.2% lime and 75 min of cooking. Cooking with the lime solution is more effective in reducing phytic acid than cooking with water. Steeping maize in lime solution at 50 degrees C during 8 h reduced phytic acid an additional 8%. The total loss of phytic acid from maize to tortilla was 22%. Calcium content increased in whole maize, endosperm, and germ with lime concentration and cooking and steeping times. The increase was higher in the germ than in the endosperm. The level, however, can be controlled if steeping of the cooked grain is conducted in water. Iron and zinc contents were not affected by nixtamalization processing variables but were affected in steeping.

  5. Cell layer-specific distribution of transiently expressed barley ESCRT-III component HvVPS60 in developing barley endosperm.

    Science.gov (United States)

    Hilscher, Julia; Kapusi, Eszter; Stoger, Eva; Ibl, Verena

    2016-01-01

    The significance of the endosomal sorting complexes required for transport (ESCRT)-III in cereal endosperm has been shown by the identification of the recessive mutant supernumerary aleurone layer1 (SAL1) in maize. ESCRT-III is indispensable in the final membrane fission step during biogenesis of multivesicular bodies (MVBs), responsible for protein sorting to vacuoles and to the cell surface. Here, we annotated barley ESCRT-III members in the (model) crop Hordeum vulgare and show that all identified members are expressed in developing barley endosperm. We used fluorescently tagged core ESCRT-III members HvSNF7a/CHMP4 and HvVPS24/CHMP3 and the associated ESCRT-III component HvVPS60a/CHMP5 for transient localization studies in barley endosperm. In vivo confocal microscopic analyses show that the localization of recombinantly expressed HvSNF7a, HvVPS24 and HvVPS60a differs within barley endosperm. Whereas HvSNF7a induces large agglomerations, HvVPS24 shows mainly cytosolic localization in aleurone and subaleurone. In contrast, HvVPS60a localizes strongly at the plasma membrane in aleurone. In subaleurone, HvVPS60a was found to a lesser extent at the plasma membrane and at vacuolar membranes. These results indicate that the steady-state association of ESCRT-III may be influenced by cell layer-specific protein deposition or trafficking and remodelling of the endomembrane system in endosperm. We show that sorting of an artificially mono-ubiquitinated Arabidopsis plasma membrane protein is inhibited by HvVPS60a in aleurone. The involvement of HvVPS60a in different cell layer-specific trafficking pathways, reflected by localization of HvVPS60a at the plasma membrane in aleurone and at the PSV membrane in subaleurone, is discussed.

  6. Maternal control of Pol IV-dependent siRNAs in Arabidopsis endosperm.

    Science.gov (United States)

    Mosher, Rebecca A

    2010-04-01

    Small RNAs recently emerged as ubiquitous regulators of gene expression. However, the most abundant class of small RNAs in flowering plants is poorly understood. Known as Pol IV-dependent (p4-)siRNAs, these small RNAs are associated with transcriptional gene silencing, transposable elements and heterochromatin formation. Recent research demonstrates that they are initially expressed in the maternal gametophyte and uniparentally expressed from maternal chromosomes in developing endosperm. This unique expression pattern links p4-siRNAs to double fertilization, parental genome interactions and imprinted gene expression.

  7. The y1 gene of maize codes for phytoene synthase.

    Science.gov (United States)

    Buckner, B; Miguel, P S; Janick-Buckner, D; Bennetzen, J L

    1996-05-01

    The cloned y1 locus of maize was sequenced and found to encode phytoene synthase. Different "wild-type" alleles of the locus were found to differ by the insertion of transposable elements in their promoter and polyA addition regions, and by the length of a CCA tandem repeat series, without any obvious effect on function of the gene. A dominant Y1 ("wild-type") allele was observed to be expressed at highest levels in the seedling but also in the embryo and endosperm. The Mu3 transposable element insertion responsible for a pastel allele of y1, which gives lowered levels of carotenoids in the endosperm of kernels and seedlings grown at high temperatures, was located in the 5' end of the gene. Although the size of the transcript from this y1 mutation suggests that the Mu3 element provides the promoter for this allele, leaf tissue in this mutant line contained approximately normal amounts of y1 mRNA. A recessive allele of y1, which conditions normal levels of carotenoids in the embryo and seedling, but almost no carotenoids in the endosperm, was found to accumulate normal amounts of y1 mRNA in the seedling and embryo, while y1 transcripts were not detected in the endosperm.

  8. Rapid Detection Method of Moldy Maize Kernels Based on Color Feature

    Directory of Open Access Journals (Sweden)

    Xuan Chu

    2014-05-01

    Full Text Available In order to find the moldy maize kernels quickly, a method based on machine vision was proposed in this paper. Firstly, images of maize kernels were taken by the moldy maize sorting equipment, and three parts of every kernel, that is, moldy plaques, healthy endosperm and healthy embryo, were selected from these images. Then a threshold was set in R channel by analyzing color features of those three parts in RGB model. In this method, moldy plaques can be identified roughly. After that the location of the moldy plaques on the kernels was studied, a circle, whose centre was approximately the centroid of a maize kernel and diameter was about the width of embryos, was set to exclude the interference caused by shadow. This method, with the accuracy of 92.1%, laid a good foundation for the further study of moldy maize sorting equipment.

  9. Climatic and non-climatic drivers of spatiotemporal maize-area dynamics across the northern limit for maize production

    DEFF Research Database (Denmark)

    Odgaard, Mette Vestergaard; Bøcher, Peder Klith; Dalgaard, Tommy

    2011-01-01

    density [in Denmark, maize is mainly grown for ensilage to feed livestock], and sandy soil [facilitates maize growing in cold areas due to higher soil temperature than loamy soils]). Our results indicate that there has been a geographical expansion of maize in Denmark from 1999 to 2008, with a strong link...

  10. Imprinting of the MEDEA polycomb gene in the Arabidopsis endosperm.

    Science.gov (United States)

    Kinoshita, T; Yadegari, R; Harada, J J; Goldberg, R B; Fischer, R L

    1999-10-01

    In flowering plants, two cells are fertilized in the haploid female gametophyte. Egg and sperm nuclei fuse to form the embryo. A second sperm nucleus fuses with the central cell nucleus that replicates to generate the endosperm, which is a tissue that supports embryo development. MEDEA (MEA) encodes an Arabidopsis SET domain Polycomb protein. Inheritance of a maternal loss-of-function mea allele results in embryo abortion and prolonged endosperm production, irrespective of the genotype of the paternal allele. Thus, only the maternal wild-type MEA allele is required for proper embryo and endosperm development. To understand the molecular mechanism responsible for the parent-of-origin effects of mea mutations on seed development, we compared the expression of maternal and paternal MEA alleles in the progeny of crosses between two Arabidopsis ecotypes. Only the maternal MEA mRNA was detected in the endosperm from seeds at the torpedo stage and later. By contrast, expression of both maternal and paternal MEA alleles was observed in the embryo from seeds at the torpedo stage and later, in seedling, leaf, stem, and root. Thus, MEA is an imprinted gene that displays parent-of-origin-dependent monoallelic expression specifically in the endosperm. These results suggest that the embryo abortion observed in mutant mea seeds is due, at least in part, to a defect in endosperm function. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds supports the parental conflict theory for the evolution of imprinting in plants and mammals.

  11. Transcript and metabolite signature of maize source leaves suggests a link between transitory starch to sucrose balance and the autonomous floral transition.

    Science.gov (United States)

    Coneva, Viktoriya; Guevara, David; Rothstein, Steven J; Colasanti, Joseph

    2012-09-01

    Little is known about the nature of floral inductive cues in day-neutral plants that are insensitive to photoperiod variations and, therefore, rely on endogenous signals to initiate reproductive growth. The INDETERMINATE1 (ID1) transcription factor is a key regulator of the transition to flowering in day-neutral maize. The ID1 gene is expressed exclusively in developing leaves, where it controls the production or transmission of leaf-derived florigenic signals. Florigen-producing source leaves were compared with mature leaves of late-flowering id1 plants, and metabolite and gene expression differences associated with the floral transition in maize were observed. While id1 mutants have a similar capacity for photosynthesis to wild-type siblings, id1 source leaves show quantitative differences in carbohydrate allocation prior to the floral transition stage, with a marked increase in sucrose and other soluble sugars, accompanied by a decrease in tricarboxylic acid (TCA) cycle organic acids. Importantly, source leaves of autonomous-flowering maize are typified by a higher transitory starch to sucrose ratio and a transcript profile enriched for sucrose synthesis and starch metabolism-related gene function. Finally, similar changes in transitory starch and sucrose are not observed in teosinte, the tropical progenitor of maize that requires short-day photoperiods to induce flowering. Together, these data define a transcript and metabolite signature associated with the autonomous floral transition in temperate maize leaves.

  12. [Effect of the prolamins in maize (Zea mays L.) grain on tortilla texture].

    Science.gov (United States)

    Sánchez, F C; Salinas, M Y; Vázquez, C M G; Velázquez, C G A; Aguilar, G N

    2007-09-01

    The prolamins (zeins) are the main storage proteins in the maize grain. There are limited investigations related to their participation on tortilla texture. For determining their effect, normal (6) and Quality Protein Maize (QPM) (6) genotypes were used. The chemical variables comprised prolamins, amylose and starch in whole grain and endosperm. Viscosity of the raw endosperm flour was determined as well as the tortilla texture, expressed in terms of tension force and elongation. Prolamin content in the normal maizes was 64 % higher than that in the QPMs. It was not observed any relationship between prolamin content and flour viscosity. The prolamin content was not related with tortilla hardness, measured as the tension force to rupture the tortilla, but a negative correlation was observed with tortilla elongation. The tortillas with the best texture characteristics were from H-161 nomal maize and H-143 QPM maize, both genotypes showed the smallest grain in its respective gruop. According to the results obtained in the present work, a high prolamin content in maize grain could be affecting tortilla elongation.

  13. Effect of Maize Hybrid Maturity and Grain Hardness on Fumonisin and Zearalenone Contamination

    Directory of Open Access Journals (Sweden)

    Amedeo Reyneri

    2011-02-01

    Full Text Available The level of resistance in commercial hybrids for Fusarium ear rot is still not in general adequate to prevent unacceptable toxin concentrations in field. The purpose of this experiment was to verify the behaviour of commercial dent maize hybrids for fumonisin and zearalenone contamination and to identify the variety traits that influence the production of these toxins. Field experiments were carried out in 2000, 2001 and 2002 to evaluate the effect of maize hybrid maturity and endosperm hardness on European Corn Borer (ECB incidence, fungal ear rot incidence and severity and on fumonisin B1 and zearalenone contents. Nineteen yellow soft commercial hybrids, from the 500, 600 and 700 FAO maturity groups, were compared in 4 sites in NW Italy. Hybrid were grouped in 3 endosperm hardness categories (hard, intermediate, soft in function of Hard/Soft (H/S endosperm ratio. No effect due to endosperm hardness or hybrid maturity on the ECB infestation or fungal ear rot incidence and severity was observed. Grain hardness significant influenced fumonisin B1 content: hard endosperm hybrids showed 50% lower contamination than soft hybrids. The presence of fumonisin B1 in the grain of different maturity hybrids only resulted to be significantly different in 2001 experiment, with a mean concentration 2 times higher in the later hybrids (FAO rating 700 compared to the medium and medium-late hybrids. The zearalenone content never resulted to be significantly different in function of the endosperm hardness, while, late maturing hybrids, in which grain moisture content decreases slowly below 30%, are more susceptible to zearalenone contamination. This research has highlighted the presence of variety traits that can influence mycotoxin contamination. An accurate choice of hybrid, considering the territorial and cultivation context, could contribute to achieve products, that contain mycotoxins, which do not exceed the maximum international and UE regulation levels.

  14. Expression analysis of genes encoding mitogen-activated protein kinases in maize provides a key link between abiotic stress signaling and plant reproduction.

    Science.gov (United States)

    Sun, Wei; Chen, Hao; Wang, Juan; Sun, Hong Wei; Yang, Shu Ke; Sang, Ya Lin; Lu, Xing Bo; Xu, Xiao Hui

    2015-01-01

    Mitogen-activated protein kinases (MAPKs) play important roles in stress responses and development in plants. Maize (Zea mays), an important cereal crop, is a model plant species for molecular studies. In the last decade, several MAPKs have been identified in maize; however, their functions have not been studied extensively. Genome-wide identification and expression analysis of maize MAPK genes could provide valuable information for understanding their functions. In this study, 20 non-redundant maize MAPK genes (ZmMPKs) were identified via a genome-wide survey. Phylogenetic analysis of MAPKs from maize, rice (Oryza sativa), Arabidopsis (Arabidopsis thaliana), poplar (Populus trichocarpa), and tomato (Solanum lycopersicum) classified them into four major classes. ZmMPKs in the same class had similar domains, motifs, and genomic structures. Gene duplication investigations suggested that segmental duplications made a large contribution to the expansion of ZmMPKs. A number of cis-acting elements related to plant development and response to stress and hormones were identified in the promoter regions of ZmMPKs. Furthermore, transcript profile analysis in eight tissues and organs at various developmental stages demonstrated that most ZmMPKs were preferentially expressed in reproductive tissues and organs. The transcript abundance of most ZmMPKs changed significantly under salt, drought, cold, or abscisic acid (ABA) treatments, implying that they might participate in abiotic stress and ABA signaling. These expression analyses indicated that ZmMPKs might serve as linkers between abiotic stress signaling and plant reproduction. Our data will deepen our understanding of the complexity of the maize MAPK gene family and provide new clues to investigate their functions.

  15. Mapping Quantitative Trait Loci Controlling Endosperm Traits with Molecular Marker

    Institute of Scientific and Technical Information of China (English)

    XU Chen-wu; LI Tao; SUN Chang-sen; GU Shi-liang

    2002-01-01

    Based on the genetic models for triploid endosperm traits and on the methods for mapping diploid quantitative traits loci (QTLs), the genetic constitutions, components of means and genetic variances of QTL controlling endosperm traits under flanking marker genotypes of different generations were presented. From these results, a multiple linear regression method for mapping QTL underlying endosperm traits in cereals was proposed, which used the means of endosperm traits under flanking marker genotypes as a dependent variable, the coefficient of additive effect ( d ) and dominance effect ( h 1 and/or h2 ) of a putative QTL in a given interval as independent variables. This method can work at any position in a genome covered by markers and increase the estimation precision of QTL location and their effects by eliminating the interference of other relative QTLs. This method can also be easily used in other uneven data such as markers and quantitative traits detected or measured in plants and tissues different either in generations or at chromosomal ploidy levels, and in endosperm traits controlled by complicated genetic models considering the effects produced by genotypes of both maternal plants and seeds on them.

  16. Reduction of 13 kD prolamins increases recombinant protein yield and recovery rate in rice endosperm.

    Science.gov (United States)

    Kawakatsu, Taiji; Takaiwa, Fumio

    2012-11-01

    RNA silencing inducible sequence (RSIS) causes post-transcriptional gene silencing (PTGS) of 5' or 3' flanking sequence-containing genes by inhibiting proper transcriptional termination. Exploiting this nature, 13 kD Pro-less, in which major seed storage protein (SSP) 13 kD prolamins are reduced, has been generated. In 13 kD Pro-less, other SSPs, such as glutelins, are increased as a compensation effect to maintain amino acid pool. 7Crp is the seven-linked epitope peptide derived from major cedar pollen allergens Cry j 1 and Cry j 2. When 7Crp is expressed in 13 kD Pro-less endosperm, accumulation level of 7Crp increased. Furthermore, recovery rate of 7Crp without reducing reagent increased. These findings indicate that 13 kD Pro-less endosperm provides a good production platform for recombinant proteins.

  17. Transgenic rice endosperm as a bioreactor for molecular pharming.

    Science.gov (United States)

    Ou, Jiquan; Guo, Zhibin; Shi, Jingni; Wang, Xianghong; Liu, Jingru; Shi, Bo; Guo, Fengli; Zhang, Chufu; Yang, Daichnag

    2014-04-01

    Plants provide a promising expression platform for producing recombinant proteins with several advantages in terms of high expression level, lower production cost, scalability, and safety and environment-friendly. Molecular pharming has been recognized as an emerging industry with strategic importance that could play an important role in economic development and healthcare in China. Here, this review represents the significant advances using transgenic rice endosperm as bioreactor to produce various therapeutic recombinant proteins in transgenic rice endosperm and large-scale production of OsrHSA, and discusses the challenges to develop molecular pharming as an emerging industry with strategic importance in China.

  18. EFFECT OF ENDOSPERM HARDNESS ON AN ETHANOL PROCESS USING A GRANULAR STARCH HYDROLYZING ENZYME

    Energy Technology Data Exchange (ETDEWEB)

    Wang, P; W Liu, D B; Johnston, K D; Rausch, S J; Schmidt, M E; Tumbleson, V Singh

    2010-01-01

    Granular starch hydrolyzing enzymes (GSHE) can hydrolyze starch at low temperature (32°C). The dry grind process using GSHE (GSH process) has fewer unit operations and no changes in process conditions (pH 4.0 and 32°C) compared to the conventional process because it dispenses with the cooking and liquefaction step. In this study, the effects of endosperm hardness, protease, urea, and GSHE levels on GSH process were evaluated. Ground corn, soft endosperm, and hard endosperm were processed using two GSHE levels (0.1 and 0.4 mL per 100 g ground material) and four treatments of protease and urea addition. Soft and hard endosperm materials were obtained by grinding and sifting flaking grits from a dry milling pilot plant; classifications were confirmed using scanning electron microscopy. During 72 h of simultaneous granular starch hydrolysis and fermentation (GSHF), ethanol and glucose profiles were determined using HPLC. Soft endosperm resulted in higher final ethanol concentrations compared to ground corn or hard endosperm. Addition of urea increased final ethanol concentrations for soft and hard endosperm. Protease addition increased ethanol concentrations and fermentation rates for soft endosperm, hard endosperm, and ground corn. The effect of protease addition on ethanol concentrations and fermentation rates was most predominant for soft endosperm, less for hard endosperm, and least for ground corn. Samples (soft endosperm, hard endosperm, or corn) with protease resulted in higher (1.0% to 10.5% v/v) ethanol concentration compared to samples with urea. The GSH process with protease requires little or no urea addition. For fermentation of soft endosperm, GSHE dose can be reduced. Due to nutrients (lipids, minerals, and soluble proteins) present in corn that enhance yeast growth, ground corn fermented faster at the beginning than hard and soft endosperm.

  19. Genotyping of endosperms to determine seed dormancy genes regulating germination through embryonic, endospermic, or maternal tissues in rice.

    Science.gov (United States)

    Gu, Xing-You; Zhang, Jinfeng; Ye, Heng; Zhang, Lihua; Feng, Jiuhuan

    2015-02-01

    Seed dormancy is imposed by one or more of the embryo, endosperm, and maternal tissues that belong to two generations and represent two ploidy levels. Many quantitative trait loci (QTL) have been identified for seed dormancy as measured by gross effects on reduced germination rate or delayed germination in crop or model plants. This research developed an endosperm genotype-based genetic approach to determine specific tissues through which a mapped QTL regulates germination using rice as a model. This approach involves testing germination velocity for partially after-ripened seeds harvested from single plants heterozygous for a tested QTL and genotyping endosperms from individual germinated and nongerminated seeds with a codominant DNA marker located on the QTL peak region. Information collected about the QTL includes genotypic frequencies in germinated and/or nongerminated subpopulations; allelic frequency distributions during a germination period; endosperm or embryo genotypic differences in germination velocity; and genotypic frequencies for gametes involved in the double fertilization to form the sampled seeds. Using this approach, the seed dormancy loci SD12, SD1-2, and SD7-1 were determined to regulate germination through the embryo, endosperm, and maternal tissues, respectively; SD12 and SD1-2 acted additively on germination velocity in the offspring tissues; and SD12 also was associated with the preferential fertilization of male gametes in rice. This new genetic approach can be used to characterize mapped genes/QTL for tissue-specific functions in endospermic seeds and for marker-assisted selection of QTL alleles before or immediately after germination in crop breeding.

  20. MAIZE POPULATIONS

    African Journals Online (AJOL)

    2003-06-17

    Jun 17, 2003 ... ZM607 at two drought stressed and one well-watered environment for yield and secondary traits. ... et à la grande interaction génotype-environnement entre le Mexique ou dépistage a ...... by CIMMYT and the Maize and Wheat .... Thesis. May, L.H. and Milthorpe, F.L. 1962. Drought resistance of crop plants.

  1. Methods for mapping QTLs underlying endosperm traits based on random hybridization design

    Institute of Scientific and Technical Information of China (English)

    WEN Yongxian; WU Weiren

    2006-01-01

    Several methods of interval mapping of QTLs underlying endosperm traits based on random hybridization designs and the triploid genetic model are proposed. The basic idea is: plants (or lines) from a population with known marker genotype information are randomly hybridized to generate a population of hybrid lines for endosperm QTL mapping; a mixture of seeds of each hybrid line is measured for the endosperm trait to get the mean of the line; then endosperm QTL mapping and effect estimation is performed using the endosperm trait means of hybrid lines and the marker genotype information of parental plants (or lines). The feasibility and efficiency of the methods are examined by computer simulations. Results show that the methods can precisely map endosperm QTLs and unbiasedly and efficiently estimate the three effects (additive effect, first dominant effect, second dominant effect) of endosperm QTLs.

  2. Widespread Contamination of Arabidopsis Embryo and Endosperm Transcriptome Data Sets.

    Science.gov (United States)

    Schon, Michael A; Nodine, Michael D

    2017-04-01

    A major goal of global gene expression profiling in plant seeds has been to investigate the parental contributions to the transcriptomes of early embryos and endosperm. However, consistency between independent studies has been poor, leading to considerable debate. We have developed a statistical tool that reveals the presence of substantial RNA contamination from maternal tissues in nearly all published Arabidopsis thaliana endosperm and early embryo transcriptomes generated in these studies. We demonstrate that maternal RNA contamination explains the poor reproducibility of these transcriptomic data sets. Furthermore, we found that RNA contamination from maternal tissues has been repeatedly misinterpreted as epigenetic phenomena, which has resulted in inaccurate conclusions regarding the parental contributions to both the endosperm and early embryo transcriptomes. After accounting for maternal RNA contamination, no published genome-wide data set supports the concept of delayed paternal genome activation in plant embryos. Moreover, our analysis suggests that maternal and paternal genomic imprinting are equally rare events in Arabidopsis endosperm. Our publicly available software (https://github.com/Gregor-Mendel-Institute/tissue-enrichment-test) can help the community assess the level of contamination in transcriptome data sets generated from both seed and non-seed tissues. © 2017 American Society of Plant Biologists. All rights reserved.

  3. Effects of salts on the gelatinization and retrogradation properties of maize starch and waxy maize starch.

    Science.gov (United States)

    Wang, Wei; Zhou, Hongxian; Yang, Hong; Zhao, Siming; Liu, Youming; Liu, Ru

    2017-01-01

    The objective of this study was to evaluate the effects of salts on the gelatinization and retrogradation of maize and waxy maize starch. Experimental results showed that the salting-out or structure-making ions, such as F(-) and SO4(2-), decreased the swelling power, solubility and transparency of both starches, but increased the gelatinization temperature, enthalpy, and syneresis, due to the tendency of these ions to protect the hydrogen bond links among starch molecules. On the other hand, the salting-in or structure-breaking ions, such as I(-) and SCN(-), exhibited the opposite effects. Microscopic observations confirmed such effects of salts on both starches. Furthermore, the effects of salts were more significant on waxy maize and on normal maize starch. Generally, salts could significantly influence on the gelatinization and retrogradation of maize and waxy maize starch, following the order of the Hofmeister series.

  4. Approaches in breeding for high quality protein maize

    Directory of Open Access Journals (Sweden)

    Denić Miloje

    2008-01-01

    Full Text Available Maize is the principal crop and major staple food in the most African and South American countries. The main problem in human nutrition in developing countries, and in livestock feed in developed countries, is insufficient production and poor quality of cereal proteins. In the case of maize, due to the very low content of essential amino acids lysine and tryptophan in grain endosperm, biological value is very low, which is main limiting factor of common maize in human nutrition and feeding of monogastric animals. Quality protein maize (QPM can help in solving of this problem. Maize production also faces serious constraints caused by agro-ecological conditions and poor socio-economic situation. To alleviate the effect of the constraints, selected genotypes with more desirable traits and appropriate field-plot techniques to create multiple-stress conditions, were used. It was found that, in downy mildew nursery distance up to 35 m from spreader plot is providing sufficient down load of spores for plant infection, provided that the testing breeding materials are planted towards to down-stream direction of the dominant wind. Using these breeding approaches large number of early, white and flint synthetics, composites and inbred lines were created with resistance or tolerance to downy mildew (DMR, maize streak virus (SR and drought (DT. Created genotypes exhibited very good kernel modification and yield potential under low and normal inputs. In the case of synthetics and composites, besides tolerance to multiple stress factors, they were competing in yield with local QPM and normal maize checks. In the case of created inbred lines high combining ability was exhibited both in non-conventional and conventional maize hybrids. Trial data revealed that in the most cases the best entries were over-yielding the best checks.

  5. FRAKSINASI ENZIM LIPASE DARI ENDOSPERM KELAPA DENGAN METODE SALTING OUT (Lipase fractionation of Coconut Endosperm by Salting out Method

    Directory of Open Access Journals (Sweden)

    Moh. Su'i

    2014-02-01

    Full Text Available This research learns about fractionation of lipases activity from coconut endosperm by using ammonium sulphate of 0–15%; 15-30 %, 30–45 %, 45–60 %, 60–75 % and 75–90 %. The results showed that the fractions of 0–15% ; 30–45 %, 45–60 % and 60–75 % have lipase activity. Meanwhile, the highest activity was fractions of 60-75%. fractions of 15-30% and 75-90%  have no lipase enzym activity. Molecule weigh of lipase enzyme was 72 kDa. Keywords: Lipases, endosperm, coconut, fractionation, ammonium sulphate   ABSTRAK Penelitian ini mempelajari fraksinasi enzim lipase dari endosperm kelapa menggunakan ammonium sulfat. fraksinasi dilakukan dengan variasi konsentrasi ammonium sulfat 0–15% ; 15-30%; 30–45 %, 45–60 %, 60–75 % dan 75–90 %. Hasil penelitian menunjukkan bahwa enzim lipase terdapat pada fraksi 0–15% ; 30–45 %, 45–60 % dan fraksi 60–75 % dengan aktivitas enzim tertinggi pada fraksi 60-75%. Sedangkan fraksi 15-30% dan 75-90% tidak ada enzim lipase. Berat molekul enzim lipase pada semua fraksi 72 kDa. Kata kunci: Lipase, endosperm, fraksinasi, ammonium sulfat

  6. Romanian maize

    DEFF Research Database (Denmark)

    Sauer, Johannes; Balint, Borbala

    This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture su...... concavity on the shadow cost frontier leads to relative differences in the efficiency es-timates of up to 240%.......This research aims at shedding empirical light on the relative efficiency of small-scale maize producers in Romania. Farmers in transition countries still face heavily distorted price systems resulting from imperfect market conditions and socioeconomic and institutional constraints. To capture...... such distortions we formulate a stochastic shadow-cost frontier model to investigate the systematic input-specific allocative inef-ficiency. We further adjust the underlying cost frontier by incorporating shadow price corrections and subsequently reveal evidence on farm specific technical inefficiency. Different...

  7. ADP-glucose pyrophosphorylase in shrunken-2 and brittle-2 mutants of maize.

    Science.gov (United States)

    Giroux, M J; Hannah, L C

    1994-05-25

    The Shrunken-2 (Sh2) and Brittle-2 (Bt2) genes of maize encode subunits of the tetrameric maize endosperm ADPglucose pyrophosphorylase. However, in all sh2 and bt2 mutants so far examined, measurable ADPglucose pyrophosphorylase activity remains. We have investigated the origin of the residual activity found in various sh2 and bt2 mutants as well as tissue specific expression and post-translational modification of the Sh2 and Bt2 proteins. Sh2 and Bt2 cDNAs were expressed in Escherichia coli and antibodies were prepared against the resulting proteins SH2 and BT2 specific antibodies were used to demonstrate that SH2 and BT2 are endosperm specific, are altered or missing in various sh2 or bt2 mutants, and have a mol. wt. of 54 and 51 kDa respectively in the wild type. The Sh2 and Bt2 transcripts are also endosperm specific. Ten sh2 and eight bt2 mutants show varying severity of phenotypes expressed at transcript, protein subunit and kernel level. Synthesis of multiple transcripts and proteins commonly occurs as a result of sh2 or bt2 mutation. While all mutants produce detectable enzymic activity, not all produce detectable transcripts and proteins. To examine the origin of the apparent non-SH2/BT2 endosperm enzymic activity, homologs of Sh2 and Bt2, designated Agp1 and Agp2 respectively, were isolated from an embryo cDNA library and found to hybridize to endosperm transcripts distinct from those of Sh2 and Bt2. Thus Agp1 and Agp2 or closely related genes may be responsible for the residual activity in some sh2 and bt2 mutants. Surprisingly, no evidence of post-translational modification of the SH2 and BT2 protein subunits was detected.

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

    Directory of Open Access Journals (Sweden)

    Jian-Hong Xu

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

  9. The Pic19 NBS-LRR gene family members are closely linked to Scmv1, but not involved in maize resistance to sugarcane mosaic virus

    DEFF Research Database (Denmark)

    Jiang, Lu; Ingvardsen, Christina Rønn; Lübberstedt, Thomas;

    2008-01-01

    Sugarcane mosaic virus (SCMV) is the causal pathogen for a severe mosaic virus disease of maize worldwide. In our previous research, the maize resistance gene analog (RGA) Pic19 and its three cognate BAC contigs were mapped to the same region as the SCMV resistance gene Scmv1. Here we report...... the isolation and characterization of the Pic19R gene family members from the inbred line FAP1360A, which shows complete resistance to SCMV. Two primer pairs were designed based on the conserved regions among the known Pic19 paralogs and used for rapid amplification of cDNA ends of FAP1360A. Six full-length c......DNAs, corresponding to the Pic19R-1 to -6 paralogs, were obtained. Three of them (Pic19R-1 to -3) had uninterrupted coding sequences and were, therefore, regarded as candidates for the Scmv1 gene. A total of 18 positive BAC clones harboring the Pic19R-2 to -5 paralogs were obtained from the FAP1360A BAC library...

  10. Effects of Different Comsteep Liquids on Structure of Starch and Protein Binding in Corn Endosperm

    OpenAIRE

    Rong Yan; Xinhua Li; Xiaojun Qi

    2015-01-01

    The changes in the structures of corn endosperms immersed in different reagents were studied, in order to preliminarily determine the mode of binding of starch and protein in the endosperm. The corn endosperm was immersed in Sulfurous acid, NaOH, ethanol, L-cysteine and morel berry, respectively. The dissociated starch content was analyzed using water as the reference. The results of the treatment were analyzed by the dissociated starch content, optical microscopy and scanning electron micros...

  11. DNA endoreplication level in endosperm during seed development in three monocotyledonous species

    Directory of Open Access Journals (Sweden)

    Kazimierz Marciniak

    2014-02-01

    Full Text Available The DNA content after the Feulgen reaction in the endosperm of three monocotyledonous plant species (Asparagus officinalis, Muscari comosom, Haemanthus kurharinae differing in their 2C DNA content, was cytophotometrically measured. During endosperm development 1-6 endoreplication cycles take place, depending on the species. Differences in nuclear DNA endoreplication dynamics in the tested species are similar to those occurring in root parenchyma, but the endoreplication level in the endosperm is higher.

  12. Circadian oscillation of starch branching enzyme gene expression in the sorghum endosperm

    Science.gov (United States)

    Mutisya, Joel; Sun, Chuanxin

    2009-01-01

    Expression of the three SBE genes, encoding starch branching enzymes, in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle. Remarkably, the oscillation in SBE expression was maintained in cultured spikes after a 48-h dark treatment, also when fed a continuous solution of sucrose or abscisic acid. Our findings suggest that the rhythmicity in SBE expression in the endosperm is independent of cues from the photosynthetic source and that the oscillator resides within the endosperm itself. PMID:19847113

  13. Circadian oscillation of starch branching enzyme gene expression in the sorghum endosperm

    Energy Technology Data Exchange (ETDEWEB)

    Mutisya, J.; Sun, C.; Jansson, C.

    2009-08-31

    Expression of the three SBE genes, encoding starch branching enzymes, in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle. Remarkably, the oscillation in SBE expression was maintained in cultured spikes after a 48-h dark treatment, also when fed a continuous solution of sucrose or abscisic acid. Our findings suggest that the rhythmicity in SBE expression in the endosperm is independent of cues from the photosynthetic source and that the oscillator resides within the endosperm itself.

  14. Possible Roles for Polycomb Repressive Complex 2 in Cereal Endosperm

    Directory of Open Access Journals (Sweden)

    Kaoru eTonosaki

    2015-03-01

    Full Text Available The Polycomb Repressive Complex 2 (PRC2 is an evolutionarily conserved multimeric protein complex in both plants and animals. In contrast to animals, plants have evolved a range of different components of PRC2 and form diverse complexes that act in the control of key regulatory genes at many stages of development during the life cycle. A number of studies, particularly in the model species Arabidopsis thaliana, have highlighted the role of PRC2 and of epigenetic controls via parent-of-origin specific gene expression for endosperm development. However, recent research in cereal plants has revealed that although some components of PRC2 show evolutionary conservation with respect to parent-of-origin specific gene expression patterns, the identity of the imprinted genes encoding PRC2 components is not conserved. This disparity may reflect the facts that cereal plant genomes have undergone different patterns of duplication during evolution compared to Arabidopsis thaliana and that the endosperm development program is not identical in monocots and eudicots. In this context, we focus this review on the expression of imprinted PRC2 genes and their roles in endosperm development in cereals.

  15. Protein accumulation in aleurone cells, sub-aleurone cells and the center starch endosperm of cereals.

    Science.gov (United States)

    Zheng, Yankun; Wang, Zhong

    2014-10-01

    There are mainly three endosperm storage tissues in the cereal endosperm: aleurone cells, sub-aleurone cells and the center starch endosperm. The protein accumulation is very different in the three endosperm storage tissues. The aleurone cells accumulate protein in aleurone granules. The sub-aleurone cells and the center starch endosperm accumulate protein in endoplasmic reticulum-derived protein bodies and vacuolar protein bodies. Proteins are deposited in different patterns within different endosperm storage tissues probably because of the special storage properties of these tissues. There are several special genes and other molecular factors to mediate the protein accumulation in these tissues. Different proteins have distinct functions in the protein body formation and the protein interactions determine protein body assembly. There are both cooperation and competition relationships between protein, starch and lipid in the cereal endosperm. This paper reviews the latest investigations on protein accumulation in aleurone cells, sub-aleurone cells and the center starch endosperm. Useful information will be supplied for future investigations on the cereal endosperm development.

  16. N,N{prime}-dicyclohexylcarbodiimide cross-linking suggests a central core of helices II in oligomers of URF13, the pore-forming T-toxin receptor of cms-T maize mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Rhoads, D.M. [Duke Univ., Durham, NC (United States)]|[North Carolina State Univ., Raleigh, NC (United States); Kaspi, C.I.; Siedow, J.N. [Duke Univ., Durham, NC (United States); Levings, C.S. III [North Carolina State Univ., Raleigh, NC (United States)

    1994-08-16

    URF13 is a mitochondrially encoded, integral membrane protein found only in maize carrying the cms-T cytoplasm. URF13 is associated with cytoplasmic male sterility, Texas type, and causes susceptibility to the fungal pathogens Bipolaris maydis race T and Phyllosticta maydis. URF13 is predicted to contain three transmembrane {alpha}-helices and is a receptor for the pathotoxins (T-toxins) produced by B. maydis race T and P. maydis. Binding of T-toxin to URF13 leads to membrane permeability. Cross-linking of URF13 oligomers with N,N{prime}-dicyclohexylcarbodiimide (DCCD) protects Escherichia coli cells expressing URF13 and cms-T mitochondria from the permeability caused by T-toxin or methomyl. Using mutated forms of URF13 expressed in E. coli cells, the authors determined the molecular mechanism of DCCD protection. They separately changed Lys-37 in helix II to isoleucine (K37I-URF13) and Lys-32 in the helix I/helix II loop region to alanine (K32A-URF13). DCCD treatment of K37I-URF13-expressing cells did not protect the cells from permeability caused by T-toxin or methomyl. DCCD cross-linking was greatly reduced in K37I-URF13 and in D39V-URF13-expressing cells, but it was unaffected in K32A-URF13-expressing cells. Binding of methomyl or T-toxin decreases DCCD cross-linking of URF13 oligomers expressed in either E. coli or cms-T mitochondria. They conclude that Asp-39 in helix II is cross-linked by DCCD to Lys-37 in helix II of an adjacent URF13 molecule and that this cross-linking protects against toxin-mediated permeabilization. The results also indicate that helices II form a central core in URF13 oligomers.

  17. Delivery of prolamins to the protein storage vacuole in maize aleurone cells.

    Science.gov (United States)

    Reyes, Francisca C; Chung, Taijoon; Holding, David; Jung, Rudolf; Vierstra, Richard; Otegui, Marisa S

    2011-02-01

    Zeins, the prolamin storage proteins found in maize (Zea mays), accumulate in accretions called protein bodies inside the endoplasmic reticulum (ER) of starchy endosperm cells. We found that genes encoding zeins, α-globulin, and legumin-1 are transcribed not only in the starchy endosperm but also in aleurone cells. Unlike the starchy endosperm, aleurone cells accumulate these storage proteins inside protein storage vacuoles (PSVs) instead of the ER. Aleurone PSVs contain zein-rich protein inclusions, a matrix, and a large system of intravacuolar membranes. After being assembled in the ER, zeins are delivered to the aleurone PSVs in atypical prevacuolar compartments that seem to arise at least partially by autophagy and consist of multilayered membranes and engulfed cytoplasmic material. The zein-containing prevacuolar compartments are neither surrounded by a double membrane nor decorated by AUTOPHAGY RELATED8 protein, suggesting that they are not typical autophagosomes. The PSV matrix contains glycoproteins that are trafficked through a Golgi-multivesicular body (MVB) pathway. MVBs likely fuse with the multilayered, autophagic compartments before merging with the PSV. The presence of similar PSVs also containing prolamins and large systems of intravacuolar membranes in wheat (Triticum aestivum) and barley (Hordeum vulgare) starchy endosperm suggests that this trafficking mechanism may be common among cereals.

  18. A putative plant organelle RNA recognition protein gene is essential for maize kernel development

    Institute of Scientific and Technical Information of China (English)

    Antony M Chettoor; Gibum Yi; Elisa Gomez; Gregorio Hueros; Robert B Meeley; Philip W Becraft

    2015-01-01

    Basal endosperm transfer layer (BETL) cel s are responsible for transferring apoplastic solutes from the maternal pedicel into the endosperm, supplying the grain with compounds required for embryo development and storage reserve accumulation. Here, we analyze the maize (Zea mays L.) empty pericarp6 (emp6) mutant, which causes early arrest in grain development. The Emp6þgene function is required independently in both the embryo and endo-sperm. The emp6 mutant causes a notable effect on the differentiation of BETL cel s; the extensive cel wal ingrowths that distinguish BETL cel s are diminished and BETL marker gene expression is compromised in mutant kernels. Transposon tagging identified the emp6 locus as encoding a putative plant organel e RNA recognition (PORR) protein, 1 of 15 PORR family members in maize. The emp6 transcript is widely detected in plant tissues with highest levels in embryos and developing kernels. EMP6‐green fluorescent protein (GFP) fusion proteins transiently expressed in Nicotiana benthamiana leaves were targeted specifical y to mitochondria. These results suggest that BETL cel differentia-tion might be particularly energy intensive, or alternatively, that mitochondria might confer a developmental function.

  19. Genome-Wide Association Mapping of and Aspergillus flavus Aflatoxin Accumulation Resistance in Maize

    Science.gov (United States)

    Marilyn L. Warburton; Juliet D. Tang; Gary L. Windham; Leigh K. Hawkins; Seth C. Murray; Wenwei Xu; Debbie Boykin; Andy Perkins; W. Paul Williams

    2015-01-01

    Contamination of maize (Zea mays L.) with aflatoxin, produced by the fungus Aspergillus flavus Link, has severe health and economic consequences. Efforts to reduce aflatoxin accumulation in maize have focused on identifying and selecting germplasm with natural host resistance factors, and several maize lines with significantly...

  20. Gene discovery for improvement of kernel quality-related traits in maize

    Directory of Open Access Journals (Sweden)

    Motto M.

    2010-01-01

    Full Text Available Developing maize plants with improved kernel quality traits involves the ability to use existing genetic variation and to identify and manipulate commercially important genes. This will open avenues for designing novel variation in grain composition and will provide the basis for the development of the next generation of specialty maize. This paper provides an overview of current knowledge on the identification and exploitation of genes affecting the composition, development, and structure of the maize kernel with particular emphasis on pathways relevant to endosperm growth and development, differentiation of starch-filled cells, and biosynthesis of starches, storage proteins, lipids, and carotenoids. The potential that the new technologies of cell and molecular biology will provide for the creation of new variation in the future are also indicated and discussed.

  1. PPR8522 encodes a chloroplast-targeted pentatricopeptide repeat protein necessary for maize embryogenesis and vegetative development.

    Science.gov (United States)

    Sosso, Davide; Canut, Matthieu; Gendrot, Ghislaine; Dedieu, Annick; Chambrier, Pierre; Barkan, Alice; Consonni, Gabriella; Rogowsky, Peter M

    2012-10-01

    The pentatricopeptide repeat (PPR) domain is an RNA binding domain allowing members of the PPR superfamily to participate in post-transcriptional processing of organellar RNA. Loss of PPR8522 from maize (Zea mays) confers an embryo-specific (emb) phenotype. The emb8522 mutation was isolated in an active Mutator (Mu) population and co-segregation analysis revealed that it was tightly linked to a MuDR insertion in the first exon of PPR8522. Independent evidence that disruption of PPR8522 caused the emb phenotype was provided by fine mapping to a region of 116kb containing no other gene than PPR8522 and complementation of the emb8522 mutant by a PPR8522 cDNA. The deduced PPR8522 amino acid sequence of 832 amino acids contains 10 PPR repeats and a chloroplast target peptide, the function of which was experimentally demonstrated by transient expression in Nicotiana benthamiana. Whereas mutant endosperm is apparently normal, mutant embryos deviate from normal development as early as 3 days after pollination, are reduced in size, exhibit more or less severe morphological aberrations depending on the genetic background, and generally do not germinate. The emb8522 mutation is the first to associate the loss of a PPR gene with an embryo-lethal phenotype in maize. Analyses of mutant plantlets generated by embryo-rescue experiments indicate that emb8522 also affects vegetative plant growth and chloroplast development. The loss of chloroplast transcription dependent on plastid-encoded RNA polymerase is the likely cause for the lack of an organized thylakoid network and an albino, seedling-lethal phenotype.

  2. Impact of Improved Maize Adoption on Welfare of Farm Households in Malawi: A Panel Data Analysis

    OpenAIRE

    Bezu, Sosina; Kassie, Girma; Shiferaw, Bekele; Ricker-Gilbert, Jacob

    2013-01-01

    This paper assesses improved maize adoption in Malawi and examines the link between adoption and household welfare using a three-year household panel data. The distributional effect of maize technology adoption is also investigated by looking at impacts across wealth and gender groups. We applied control function approach and IV regression to control for endogeneity of input subsidy and improved maize adoption. We found that modern maize variety adoption is positively correlated with the hous...

  3. Effect of nitrogen fertilizer on distribution of starch granules in different regions of wheat endosperm

    Institute of Scientific and Technical Information of China (English)

    Fei; Xiong; Xurun; Yu; Liang; Zhou; Jing; Zhang; Yanping; Jin; Dongliang; Li; Zhong; Wang

    2014-01-01

    This study provided visual evidence of a nitrogen effect on starch granules(SGs) in wheat endosperm. Winter wheat(Titicum aestivum L.) cultivar Xumai 30 was cultured under no nitrogen(control) and 240 kg ha-1of nitrogen applied at the booting stage. The number, morphology, and size of Aand B-type SGs in subaleurone of dorsal endosperm(SDE), center of dorsal endosperm(CDE), modified aleurone(MA), subaleurone of ventral endosperm(SVE), and center of ventral endosperm(CVE) were observed under light and electron microscopes.(1) The distribution of SGs in SDE was similar to that in SVE, the distributions of SGs in CDE and CVE were similar, but the distribution of SGs in MA was different from those in the other four endosperm regions. The number of SGs in the five endosperm regions was in the order SDE > CDE > SVE > CVE > MA.(2) Nitrogen increased the number of Aand B-type SGs in SDE and SVE. Nitrogen also increased the number of B-type SGs but decreased the number of A-type SGs in CDE and CVE. Nitrogen decreased the numbers of A-type and B-type SGs in MA. The results suggest that increased N fertilizer application mainly increased the numbers of small SGs and decreased the numbers of large SGs, but that the results varied in different regions of the wheat endosperm.

  4. Effect of nitrogen fertilizer on distribution of starch granules in different regions of wheat endosperm

    Directory of Open Access Journals (Sweden)

    Fei Xiong

    2014-02-01

    Full Text Available This study provided visual evidence of a nitrogen effect on starch granules (SGs in wheat endosperm. Winter wheat (Titicum aestivum L. cultivar Xumai 30 was cultured under no nitrogen (control and 240 kg ha− 1 of nitrogen applied at the booting stage. The number, morphology, and size of A- and B-type SGs in subaleurone of dorsal endosperm (SDE, center of dorsal endosperm (CDE, modified aleurone (MA, subaleurone of ventral endosperm (SVE, and center of ventral endosperm (CVE were observed under light and electron microscopes. (1 The distribution of SGs in SDE was similar to that in SVE, the distributions of SGs in CDE and CVE were similar, but the distribution of SGs in MA was different from those in the other four endosperm regions. The number of SGs in the five endosperm regions was in the order SDE > CDE > SVE > CVE > MA. (2 Nitrogen increased the number of A- and B-type SGs in SDE and SVE. Nitrogen also increased the number of B-type SGs but decreased the number of A-type SGs in CDE and CVE. Nitrogen decreased the numbers of A-type and B-type SGs in MA. The results suggest that increased N fertilizer application mainly increased the numbers of small SGs and decreased the numbers of large SGs, but that the results varied in different regions of the wheat endosperm.

  5. Studies on the Programmed Cell Death in Rice During Starchy Endosperm Development

    Institute of Scientific and Technical Information of China (English)

    LI Rui; LAN Sheng-yin; XU Zhen-xiu

    2004-01-01

    Morphological variations of the nucleus in starchy endosperm cell were observed by the electron-transmisson microscope during endosperm development in rice. Along with the development of the starchy endosperm,the nuclei of the cells showed chromatin condensation,the typical feature of programmed cell death(PCD). The nuclei also showed nucleus deformation,disruption of nuclear envelope,nucleoplasm leaking into the cytoplasm and nucleus disintegration resulting in nuclear residue formation. From the nucleus deformation to the nucleus disintegration,the morphological changes of the nucleus were orderly progressive. This indicated that the cell death of starchy endosperm in rice was programmed cell death. Evans Blue staining observation showed that the cell death was initially detected in the central part of starchy endosperm in rice,then expanded outward. The activities of superoxide dismutase(SOD)and catalase(CAT)in rice starchy endosperm both descended continuously as development progressed. The analysis of DNA of rice starchy endosperm did not show the presence of DNA laddering. The above results showed that the cell death of starchy endosperm in rice was a special form of PCD.

  6. Arabidopsis haiku mutants reveal new controls of seed size by endosperm.

    Science.gov (United States)

    Garcia, Damien; Saingery, Virginie; Chambrier, Pierre; Mayer, Ulrike; Jürgens, Gerd; Berger, Frédéric

    2003-04-01

    In flowering plants, maternal seed integument encloses the embryo and the endosperm, which are both derived from double fertilization. Although the development of these three components must be coordinated, we have limited knowledge of mechanisms involved in such coordination. The endosperm may play a central role in these mechanisms as epigenetic modifications of endosperm development, via imbalance of dosage between maternal and paternal genomes, affecting both the embryo and the integument. To identify targets of such epigenetic controls, we designed a genetic screen in Arabidopsis for mutants that phenocopy the effects of dosage imbalance in the endosperm. The two mutants haiku 1 and haiku 2 produce seed of reduced size that resemble seed with maternal excess in the maternal/paternal dosage. Homozygous haiku seed develop into plants indistinguishable from wild type. Each mutation is sporophytic recessive, and double-mutant analysis suggests that both mutations affect the same genetic pathway. The endosperm of haiku mutants shows a premature arrest of increase in size that causes precocious cellularization of the syncytial endosperm. Reduction of seed size in haiku results from coordinated reduction of endosperm size, embryo proliferation, and cell elongation of the maternally derived integument. We present further evidence for a control of integument development mediated by endosperm-derived signals.

  7. Division of Free Nuclei in Rice Endosperm and Its Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    LIU Man-xi; WANG Zhong; WU Xiao-mei; CHEN Yi-fang; GU Yun-jie

    2009-01-01

    The division process of endosperm in rice and its influencing factors were investigated. Total dissection, resin embedding and sectioning under light and transmission electron microscopes were used to observe the division patterns of free nuclei and cytological characters of an endosperm. The various division patterns of free nuclei in rice endosperm included mitosis, amitosis, and the mitosis to amitosis change without an interphase. The division velocity of free nuclei in rice endosperm varied with the internucleus distance. Comparing to a cluster, the division velocity increased when the free nuclei were separated from each other. Moderately higher temperatures also enhanced the proliferation and shortened the division cycle of free nuclei in rice endosperm. To a certain extent, nitrogenous fertilizer applied at the booting stage together with a moderate drought treatment accelerated the division of free nuclei as well.

  8. The Polycomb group protein MEDEA and the DNA methyltransferase MET1 interact to repress autonomous endosperm development in Arabidopsis.

    Science.gov (United States)

    Schmidt, Anja; Wöhrmann, Heike J P; Raissig, Michael T; Arand, Julia; Gheyselinck, Jacqueline; Gagliardini, Valeria; Heichinger, Christian; Walter, Joern; Grossniklaus, Ueli

    2013-03-01

    In flowering plants, double fertilization of the female gametes, the egg and the central cell, initiates seed development to give rise to a diploid embryo and the triploid endosperm. In the absence of fertilization, the FERTILIZATION-INDEPENDENT SEED Polycomb Repressive Complex 2 (FIS-PRC2) represses this developmental process by histone methylation of certain target genes. The FERTILIZATION-INDEPENDENT SEED (FIS) class genes MEDEA (MEA) and FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) encode two of the core components of this complex. In addition, DNA methylation establishes and maintains the repression of gene activity, for instance via DNA METHYLTRANSFERASE1 (MET1), which maintains methylation of symmetric CpG residues. Here, we demonstrate that Arabidopsis MET1 interacts with MEA in vitro and in a yeast two-hybrid assay, similar to the previously identified interaction of the mammalian homologues DNMT1 and EZH2. MET1 and MEA share overlapping expression patterns in reproductive tissues before and after fertilization, a prerequisite for an interaction in vivo. Importantly, a much higher percentage of central cells initiate endosperm development in the absence of fertilization in mea-1/MEA; met1-3/MET1 as compared to mea-1/MEA mutant plants. In addition, DNA methylation at the PHERES1 and MEA loci, imprinted target genes of the FIS-PRC2, was affected in the mea-1 mutant compared with wild-type embryos. In conclusion, our data suggest a mechanistic link between two major epigenetic pathways involved in histone and DNA methylation in plants by physical interaction of MET1 with the FIS-PRC2 core component MEA. This concerted action is relevant for the repression of seed development in the absence of fertilization. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  9. Characterization of opaque2 modifier QTLs and candidate genes in recombinant inbred lines derived from the K0326Y quality protein maize inbred

    KAUST Repository

    Holding, David R.

    2010-11-13

    Quality protein maize (QPM) is a high lysine-containing corn that is based on genetic modification of the opaque2 (o2) mutant. In QPM, modifier genes convert the starchy endosperm of o2 to the vitreous phenotype of wild type maize. There are multiple, unlinked o2 modifier loci (Opm) in QPM and their nature and mode of action are unknown. We previously identified seven Opm QTLs and characterized 16 genes that are differentially up-regulated at a significant level in K0326Y QPM, compared to the starchy endosperm mutant W64Ao2. In order to further characterize these Opm QTLs and the genes up-regulated in K0326Y QPM, we created a population of 314 recombinant inbred lines (RILs) from a cross between K0326Y QPM and W64Ao2. The RILs were characterized for three traits associated with endosperm texture: vitreousness, density and hardness. Genetic linkage analysis of the RIL population confirmed three of the previously identified QTLs associated with o2 endosperm modification in K0326Y QPM. Many of the genes up-regulated in K0326Y QPM showed substantially higher levels of expression in vitreous compared with opaque RILs. These included genes associated with the upstream regulation of the ethylene response pathway, and a gene encoding a regulatory subunit of pyrophosphate-dependent fructose-6-phosphate 1-phosphotransferase, an adaptive enzyme of the glycolytic pathway. © 2010 Springer-Verlag.

  10. Heterogeneous structure and spatial distribution in endosperm of high-amylose rice starch granules with different morphologies.

    Science.gov (United States)

    Cai, Canhui; Huang, Jun; Zhao, Lingxiao; Liu, Qiaoquan; Zhang, Changquan; Wei, Cunxu

    2014-10-15

    Starch granules from high-amylose cereal mutants or transgenic lines usually have different morphologies. It is not clear whether the structure and spatial distribution of starch granules with different morphologies in endosperm is homogeneous or heterogeneous. In the present study, the structure and spatial distribution in endosperm of morphologically different starch granules from high-amylose transgenic rice line (TRS) were investigated. The TRS endosperm had individual, aggregate, elongated, and interior hollow starch granules. The individual and interior hollow granules had the lowest and the highest amylose content and gelatinization resistance, respectively, among the four types of granules. The individual granules were mainly distributed in the middle of the endosperm; the aggregate granules in the starchy endosperm cells between the subaleurone layer and the middle of the endosperm; the elongated granules in the peripheral starchy endosperm cells adjacent to the subaleurone layer; and the interior hollow granules in the subaleurone layer cells.

  11. Cell wall degradation is required for normal starch mobilisation in barley endosperm.

    Science.gov (United States)

    Andriotis, Vasilios M E; Rejzek, Martin; Barclay, Elaine; Rugen, Michael D; Field, Robert A; Smith, Alison M

    2016-09-13

    Starch degradation in barley endosperm provides carbon for early seedling growth, but the control of this process is poorly understood. We investigated whether endosperm cell wall degradation is an important determinant of the rate of starch degradation. We identified iminosugar inhibitors of enzymes that degrade the cell wall component arabinoxylan. The iminosugar 1,4-dideoxy-1, 4-imino-l-arabinitol (LAB) inhibits arabinoxylan arabinofuranohydrolase (AXAH) but does not inhibit the main starch-degrading enzymes α- and β-amylase and limit dextrinase. AXAH activity in the endosperm appears soon after the onset of germination and resides in dimers putatively containing two isoforms, AXAH1 and AXAH2. Upon grain imbibition, mobilisation of arabinoxylan and starch spreads across the endosperm from the aleurone towards the crease. The front of arabinoxylan degradation precedes that of starch degradation. Incubation of grains with LAB decreases the rate of loss of both arabinoxylan and starch, and retards the spread of both degradation processes across the endosperm. We propose that starch degradation in the endosperm is dependent on cell wall degradation, which permeabilises the walls and thus permits rapid diffusion of amylolytic enzymes. AXAH may be of particular importance in this respect. These results provide new insights into the mobilization of endosperm reserves to support early seedling growth.

  12. Cell wall degradation is required for normal starch mobilisation in barley endosperm

    Science.gov (United States)

    Andriotis, Vasilios M. E.; Rejzek, Martin; Barclay, Elaine; Rugen, Michael D.; Field, Robert A.; Smith, Alison M.

    2016-01-01

    Starch degradation in barley endosperm provides carbon for early seedling growth, but the control of this process is poorly understood. We investigated whether endosperm cell wall degradation is an important determinant of the rate of starch degradation. We identified iminosugar inhibitors of enzymes that degrade the cell wall component arabinoxylan. The iminosugar 1,4-dideoxy-1, 4-imino-l-arabinitol (LAB) inhibits arabinoxylan arabinofuranohydrolase (AXAH) but does not inhibit the main starch-degrading enzymes α- and β-amylase and limit dextrinase. AXAH activity in the endosperm appears soon after the onset of germination and resides in dimers putatively containing two isoforms, AXAH1 and AXAH2. Upon grain imbibition, mobilisation of arabinoxylan and starch spreads across the endosperm from the aleurone towards the crease. The front of arabinoxylan degradation precedes that of starch degradation. Incubation of grains with LAB decreases the rate of loss of both arabinoxylan and starch, and retards the spread of both degradation processes across the endosperm. We propose that starch degradation in the endosperm is dependent on cell wall degradation, which permeabilises the walls and thus permits rapid diffusion of amylolytic enzymes. AXAH may be of particular importance in this respect. These results provide new insights into the mobilization of endosperm reserves to support early seedling growth. PMID:27622597

  13. Drought stress delays endosperm development and misregulates genes associated with cytoskeleton organization and grain quality proteins in developing wheat seeds.

    Science.gov (United States)

    Begcy, Kevin; Walia, Harkamal

    2015-11-01

    Drought stress is a major yield-limiting factor for wheat. Wheat yields are particularly sensitive to drought stress during reproductive development. Early seed development stage is an important determinant of seed size, one of the yield components. We specifically examined the impact of drought stress imposed during postzygotic early seed development in wheat. We imposed a short-term drought stress on plants with day-old seeds and observed that even a short-duration drought stress significantly reduced the size of developing seeds as well as mature seeds. Drought stress delayed the developmental transition from syncytial to cellularized stage of endosperm. Coincident with reduced seed size and delayed endosperm development, a subset of genes associated with cytoskeleton organization was misregulated in developing seeds under drought-stressed. Several genes linked to hormone pathways were also differentially regulated in response to drought stress in early seeds. Notably, drought stress strongly repressed the expression of wheat storage protein genes such as gliadins, glutenins and avenins as early as 3 days after pollination. Our results provide new insights on how some of the early seed developmental events are impacted by water stress, and the underlying molecular pathways that can possibly impact both grain size and quality in wheat.

  14. 5种谷物胚乳表层细胞的比较研究%Comparison of peripheral endosperm cell development in five cereals

    Institute of Scientific and Technical Information of China (English)

    王慧慧; 熊飞; 王峰; 刘智; 顾蕴洁; 王忠

    2011-01-01

    Light microscopy, transmission and scanning electron microscopy were employed to investigate the structure of peripheral endosperm cells (PECs) of different cereals. Results showed that the differentiation of PECs was determined by their surface position, and the development extent of PECs from different cereals was various. PECs in cereals with large grain weight were generally more developed than those in cereals with small grain weight. All wall ingrowths in endosperm transfer cells of different cereals belonged to the flange-type wall ingrowths with their long axes consistent with that of the predicted direction of the solute flow. Wall ingrowths in endosperm transfer cells of maize and sorghum were more developed than those of barley and wheat. Aleurone cells of different cereals had the similar structure with thick walls. According to the position and structure features, PECs may play an important role in apoplastic and symplas-tic transport of nutrients. The structure of endosperm transfer cells is more suitable for the transport of grain filling nutrients than that of aleurone cells.%通过光学显微镜及透射和扫描电镜研究水稻、大麦、小麦、高粱、玉米5种谷物胚乳表层细胞的结构.结果表明:胚乳表层细胞的分化具有位置效应,且不同谷物胚乳表层细胞的发育程度不同.一般而言,粒重较大的谷物其胚乳表层细胞比粒重较小的谷物发达.谷物胚乳传递细胞中壁内突皆为肋状内突,其长轴方向与溶质流运输方向一致.玉米、高粱胚乳传递细胞中的肋状内突较大麦、小麦发达.不同谷物糊粉层细胞结构类似,其细胞壁较厚.根据胚乳表层细胞分布位置和结构特点可推测,胚乳表层细胞在养分的质外体和共质体运输过程中起着重要作用,且胚乳传递细胞的结构比糊粉层细胞更适合灌浆物质的运输.

  15. In vitro biochemical characterization of all barley endosperm starch synthases

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose A.; Nielsen, Morten M.; Ruzanski, Christian;

    2016-01-01

    Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs). While the overall starch synthase (SS) reaction is known, the functional differences between the five SS...... classes are poorly understood. Much of our knowledge comes from analyzing mutant plants with altered SS activities, but the resulting data are often difficult to interpret as a result of pleitropic effects, competition between enzymes, overlaps in enzyme activity and disruption of multi-enzyme complexes....... Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results...

  16. Development of aleurone and sub-aleurone layers in maize.

    Science.gov (United States)

    Kyle, D J; Styles, E D

    1977-01-01

    Electron-microscope studies indicate that the aleurone tissue of maize (Zea mays L.) starts developing approximately 10-15 days after pollination in stocks that take ca. 40 days for the aleurone to mature completely. Development commences when specialized endosperm cells adjacent to the maternal nucellar layer start to differentiate. Differentiation is characterized by the formation of aleurone protein bodies and spherosomes. The protein bodies of the aleurone layer have a vacuolar origin whereas the protein bodies of the immediate underlying endosperm cells appear to develop from protrusions of the rough endoplasmic reticulum. Thus, two morphologically and developmentally distinct types of protein bodies are present in these adjacent tissues. The spherosomes of the aleurone layer form early in the development of this tissue and increase in number as the tissue matures. During the final stages of maturation, these spherosomes become closely apposed to the aleurone grains and the plasma membrane. No further changes are apparent in the structure of the aleurone cells after 40 days from pollination when the caryopsis begins to desiccate.

  17. Abscisic acid controls embryo growth potential and endosperm cap weakening during coffee (Coffea arabica cv. Rubi) seed germination.

    Science.gov (United States)

    da Silva, E A Amaral; Toorop, Peter E; van Aelst, Adriaan C; Hilhorst, Henk W M

    2004-12-01

    The mechanism and regulation of coffee seed germination were studied in Coffea arabica L. cv. Rubi. The coffee embryo grew inside the endosperm prior to radicle protrusion and abscisic acid (ABA) inhibited the increase in its pressure potential. There were two steps of endosperm cap weakening. An increase in cellulase activity coincided with the first step and an increase in endo-beta-mannanase (EBM) activity with the second step. ABA inhibited the second step of endosperm cap weakening, presumably by inhibiting the activities of at least two EBM isoforms and/or, indirectly, by inhibiting the pressure force of the radicle. The increase in the activities of EBM and cellulase coincided with the decrease in the force required to puncture the endosperm and with the appearance of porosity in the cell walls as observed by low-temperature scanning electronic microscopy. Tissue printing showed that EBM activity was spatially regulated in the endosperm. Activity was initiated in the endosperm cap whereas later during germination it could also be detected in the remainder of the endosperm. Tissue printing revealed that ABA inhibited most of the EBM activity in the endosperm cap, but not in the remainder of the endosperm. ABA did not inhibit cellulase activity. There was a transient rise in ABA content in the embryo during imbibition, which was likely to be responsible for slow germination, suggesting that endogenous ABA also may control embryo growth potential and the second step of endosperm cap weakening during coffee seed germination.

  18. Dynamics of early embryo development in reference to endosperm and embryo types in angiosperms

    Directory of Open Access Journals (Sweden)

    Olga Erdelska

    2014-01-01

    Full Text Available The mitotic cycle of the endosperm cells is relatively short in the firsit phases of the postfertilization development. The endosperm type does not significantly influence the duration of the mitotic cycle; it might, however, influence the dynamics of zygote and embryo development. The quick development and early end of cellular endosperm proliferation is connected with the fact that it is, in most cases, bound to small, "spare" or "saving" tenuinucellate and unitegmic ovules. Structural differences in the behaviour of the endosperm of different types, in the phase of globular and early heart embryo, might point to differences in the time or way of transition of the embryo from suspensorial to surface nutrition.

  19. Ultracytochemical Localization and Functional Analysis of ATPase During the Endosperm Development in Oryza sativa L.

    Institute of Scientific and Technical Information of China (English)

    WEI Cun-xu; LAN Sheng-yin; XU Zhen-xiu

    2003-01-01

    Ultracytochemical localization of ATPase during development of rice endosperm was performed using a lead phosphate precipitation technique. The results indicated that, at the coenocyte and ceilularization stages, active ATPase was mainly distributed in an embryo sac wall, nucleus, and plasma membrane. At the early stage of development and differentiation, active ATPase was observed in the plasma membrane. At the grain filling stage, ATPase was highly active in the plasma membrane, intercellular space, and plasmodesmata in aleurone, moderately active on the plasma membrane in subaleurone. In starchy endosperm, ATPase was localized in the plasma membrane and degenerated nucleus. ATPase activity also appeared around vacuole and protein body in endosperm cell. The relationships between the ultracytochemical localization of ATPase and its function during the development of rice endosperm were discussed. Overall, ATPase was involved in the process of nutrition absorption and protein synthesis.

  20. Expression of the gene encoding the PR-like protein PRms in germinating maize embryos.

    Science.gov (United States)

    Casacuberta, J M; Raventós, D; Puigdoménech, P; San Segundo, B

    1992-07-01

    The PRms protein is a pathogenesis-related (PR)-like protein whose mRNA accumulates during germination of maize seeds. Expression of the PRms gene is induced after infection of maize seeds with the fungus Fusarium moniliforme. To further our investigations on the expression of the PRms gene we examined the accumulation of PRms mRNA in different tissues of maize seedlings infected with F. moniliforme and studied the effect of fungal elicitors, the mycotoxin moniliformin, the hormone gibberellic acid, and specific chemical agents. Our results indicate that fungal infection, and treatment either with fungal elicitors or with moniliformin, a mycotoxin produced by F. moniliforme, increase the steady-state level of PRms mRNA. PRms mRNA accumulation is also stimulated by the application of the hormone gibberellic acid or by treatment with silver nitrate, whereas acetylsalicylic acid has no effect. In situ RNA hybridization in isolated germinating embryo sections demonstrates that the PRms gene is expressed in the scutellum, particularly in a group of inner cells, and in the epithelium lying at the interface of the scutellum and the endosperm. The pattern of expression of the PRms gene closely resembles that found for hydrolytic enzymes, being confined to the scutellum and the aleurone layer of the germinating maize seed. Our results suggest that the PRms protein has a function during the normal process of seed germination that has become adapted to serve among the defence mechanisms induced in response to pathogens during maize seed germination.

  1. The embryo and the endosperm contribute equally to argan seed oil yield but confer distinct lipid features to argan oil.

    Science.gov (United States)

    Errouane, Kheira; Doulbeau, Sylvie; Vaissayre, Virginie; Leblanc, Olivier; Collin, Myriam; Kaid-Harche, Meriem; Dussert, Stéphane

    2015-08-15

    In the perspective of studying lipid biosynthesis in the argan seed, the anatomy, ploidy level and lipid composition of mature seed tissues were investigated using an experimental design including two locations in Algeria and four years of study. Using flow cytometry, we determined that mature argan seeds consist of two well-developed tissues, the embryo and the endosperm. The lipid content of the embryo was higher than that of the endosperm, but the dry weight of the endosperm was higher. Consequently, both tissues contribute equally to seed oil yield. Considerable differences in fatty acid composition were observed between the two tissues. In particular, the endosperm 18:2 percentage was twofold higher than that of the embryo. The tocopherol content of the endosperm was also markedly higher than that of the embryo. In contrast, the endosperm and the embryo had similar sterol and triterpene alcohol contents and compositions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Estimated environmental loads of alpha-amylase from transgenic high-amylase maize

    Energy Technology Data Exchange (ETDEWEB)

    Wolt, Jeffrey D. [Department of Agronomy, Iowa State University, Ames, IA 50011 (United States); Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States); Karaman, Sule [Biosafety Institute for Genetically Modified Agricultural Products, 164 Seed Science, Iowa State University, Ames, IA 50011 (United States)

    2007-11-15

    Environmental exposure of plants bioengineered to improve efficiencies of biofuel production is an important consideration for their adoption. High-amylase maize genetically engineered to produce thermostable alpha-amylase in seed endosperm is currently in development, and its successful adoption will entail >1000 km{sup 2} of annual production in the USA. Environmental exposure of thermostable amylase will occur in production fields from preharvest and harvest dropped grain, with minor additional contributions from stover and root biomass. Mass loadings of thermostable alpha-amylase are projected to be 16 kg km{sup -2} and represent a potential source of increased alpha-amylase activity in receiving soils. An understanding of the degradation, persistence, accumulation, and activity of thermostable alpha-amylase introduced from transgenic high-amylase maize will be necessary in order to effectively manage transgenic crop systems intended or biofeedstock production. (author)

  3. Maize Genetic Resources

    Science.gov (United States)

    This chapter describes the resources held at the Maize Genetics Cooperation • Stock Center in detail and also provides some information about the North Central Regional Plant Introduction Station (NCRPIS) in Ames, IA, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) in Mexico, and the N...

  4. The thick aleurone1 mutant defines a negative regulation of maize aleurone cell fate that functions downstream of defective kernel1.

    Science.gov (United States)

    Yi, Gibum; Lauter, Adrienne M; Scott, M Paul; Becraft, Philip W

    2011-08-01

    The maize (Zea mays) aleurone layer occupies the single outermost layer of the endosperm. The defective kernel1 (dek1) gene is a central regulator required for aleurone cell fate specification. dek1 mutants have pleiotropic phenotypes including lack of aleurone cells, aborted embryos, carotenoid deficiency, and a soft, floury endosperm deficient in zeins. Here we describe the thick aleurone1 (thk1) mutant that defines a novel negative function in the regulation of aleurone differentiation. Mutants possess multiple layers of aleurone cells as well as aborted embryos. Clonal sectors of thk1 mutant tissue in otherwise normal endosperm showed localized expression of the phenotype with sharp boundaries, indicating a localized cellular function for the gene. Sectors in leaves showed expanded epidermal cell morphology but the mutant epidermis generally remained in a single cell layer. Double mutant analysis indicated that the thk1 mutant is epistatic to dek1 for several aspects of the pleiotropic dek1 phenotype. dek1 mutant endosperm that was mosaic for thk1 mutant sectors showed localized patches of multilayered aleurone. Localized sectors were surrounded by halos of carotenoid pigments and double mutant kernels had restored zein profiles. In sum, loss of thk1 function restored the ability of dek1 mutant endosperm to accumulate carotenoids and zeins and to differentiate aleurone. Therefore the thk1 mutation defines a negative regulator that functions downstream of dek1 in the signaling system that controls aleurone specification and other aspects of endosperm development. The thk1 mutation was found to be caused by a deletion of approximately 2 megabases.

  5. Effect of salicylhydroxamic acid on endosperm strength and embryo growth of Lactuca sativa L. cv Waldmann's Green seeds

    Science.gov (United States)

    Brooks, C. A.; Mitchell, C. A.

    1988-01-01

    Salicylhydroxamic acid (SHAM) stimulated germination of photosensitive lettuce (Lactuca sativa L. cv Waldmann's Green) seeds in darkness. To determine whether SHAM acts on the embryo or the endosperm, we investigated separately effects of SHAM on growth potential of isolated embryos as well as on endosperm strength. Embryo growth potential was quantified by incubating decoated embryos in various concentrations of osmoticum and measuring subsequent radicle elongation. Growth potential of embryos isolated from seeds pretreated with 4 millimolar SHAM was equal to that of untreated controls. Rupture strength of endosperm tissue excised from seeds pretreated with SHAM was 33% less than that of controls in the micropylar region. To determine if the embryo must be in contact with the endosperm of SHAM to weaken the endosperm, some endosperms were incubated with SHAM only after dissection from seeds. Rupture strength of SHAM-treated, isolated endosperms in the micropylar region was 25% less than that of untreated controls. There was no difference in rupture strength in the cotyledonary region of endosperm isolated from seeds treated with SHAM in buffer or buffer alone. SHAM therefore stimulates germination not by enhancing embryo growth potential, but by weakening the micropylar region of the endosperm enclosing the embryo.

  6. Effect of salicylhydroxamic acid on endosperm strength and embryo growth of Lactuca sativa L. cv Waldmann's Green seeds

    Science.gov (United States)

    Brooks, C. A.; Mitchell, C. A.

    1988-01-01

    Salicylhydroxamic acid (SHAM) stimulated germination of photosensitive lettuce (Lactuca sativa L. cv Waldmann's Green) seeds in darkness. To determine whether SHAM acts on the embryo or the endosperm, we investigated separately effects of SHAM on growth potential of isolated embryos as well as on endosperm strength. Embryo growth potential was quantified by incubating decoated embryos in various concentrations of osmoticum and measuring subsequent radicle elongation. Growth potential of embryos isolated from seeds pretreated with 4 millimolar SHAM was equal to that of untreated controls. Rupture strength of endosperm tissue excised from seeds pretreated with SHAM was 33% less than that of controls in the micropylar region. To determine if the embryo must be in contact with the endosperm of SHAM to weaken the endosperm, some endosperms were incubated with SHAM only after dissection from seeds. Rupture strength of SHAM-treated, isolated endosperms in the micropylar region was 25% less than that of untreated controls. There was no difference in rupture strength in the cotyledonary region of endosperm isolated from seeds treated with SHAM in buffer or buffer alone. SHAM therefore stimulates germination not by enhancing embryo growth potential, but by weakening the micropylar region of the endosperm enclosing the embryo.

  7. The trafficking pathway of a wheat storage protein in transgenic rice endosperm

    Science.gov (United States)

    Oszvald, Maria; Tamas, Laszlo; Shewry, Peter R.; Tosi, Paola

    2014-01-01

    Background and Aims The trafficking of proteins in the endoplasmic reticulum (ER) of plant cells is a topic of considerable interest since this organelle serves as an entry point for proteins destined for other organelles, as well as for the ER itself. In the current work, transgenic rice was used to study the pattern and pathway of deposition of the wheat high molecular weight (HMW) glutenin sub-unit (GS) 1Dx5 within the rice endosperm using specific antibodies to determine whether it is deposited in the same or different protein bodies from the rice storage proteins, and whether it is located in the same or separate phases within these. Methods The protein distribution and the expression pattern of HMW sub-unit 1Dx5 in transgenic rice endosperm at different stages of development were determined using light and electron microscopy after labelling with antibodies. Key results The use of HMW-GS-specific antibodies showed that sub-unit 1Dx5 was expressed mainly in the sub-aleurone cells of the endosperm and that it was deposited in both types of protein body present in the rice endosperm: derived from the ER and containing prolamins, and derived from the vacuole and containing glutelins. In addition, new types of protein bodies were also formed within the endosperm cells. Conclusions The results suggest that the HMW 1Dx5 protein could be trafficked by either the ER or vacuolar pathway, possibly depending on the stage of development, and that its accumulation in the rice endosperm could compromise the structural integrity of protein bodies and their segregation into two distinct populations in the mature endosperm. PMID:24603605

  8. Maize kernel hardness classification by near infrared (NIR) hyperspectral imaging and multivariate data analysis.

    Science.gov (United States)

    Williams, Paul; Geladi, Paul; Fox, Glen; Manley, Marena

    2009-10-27

    The use of near infrared (NIR) hyperspectral imaging and hyperspectral image analysis for distinguishing between hard, intermediate and soft maize kernels from inbred lines was evaluated. NIR hyperspectral images of two sets (12 and 24 kernels) of whole maize kernels were acquired using a Spectral Dimensions MatrixNIR camera with a spectral range of 960-1662 nm and a sisuChema SWIR (short wave infrared) hyperspectral pushbroom imaging system with a spectral range of 1000-2498 nm. Exploratory principal component analysis (PCA) was used on absorbance images to remove background, bad pixels and shading. On the cleaned images, PCA could be used effectively to find histological classes including glassy (hard) and floury (soft) endosperm. PCA illustrated a distinct difference between glassy and floury endosperm along principal component (PC) three on the MatrixNIR and PC two on the sisuChema with two distinguishable clusters. Subsequently partial least squares discriminant analysis (PLS-DA) was applied to build a classification model. The PLS-DA model from the MatrixNIR image (12 kernels) resulted in root mean square error of prediction (RMSEP) value of 0.18. This was repeated on the MatrixNIR image of the 24 kernels which resulted in RMSEP of 0.18. The sisuChema image yielded RMSEP value of 0.29. The reproducible results obtained with the different data sets indicate that the method proposed in this paper has a real potential for future classification uses.

  9. Morphology, structure and gelatinization properties of heterogeneous starch granules from high-amylose maize.

    Science.gov (United States)

    Cai, Canhui; Zhao, Lingxiao; Huang, Jun; Chen, Yifang; Wei, Cunxu

    2014-02-15

    High-amylose cereal endosperm is rich in heterogeneous starch granules. In this paper, we investigated the morphology, structure and gelatinization properties of high-amylose maize endosperm starch. Starch had individual, aggregate and elongated heterogeneous granules. Most of individual granules were round with small size and had one central hilum. Aggregate and elongated granules consisted of many subgranules with central hila, and had irregular and rod/filamentous shapes, respectively. Iodine stained starch granules showed five types of polarization colors: blue, purple, fuchsia, dark red, and interior dark blue and exterior brown. Most of individual and aggregate granules had the color of dark red, that of elongated granules the color of interior dark blue and exterior brown. Amylose was mainly distributed in the hilum region and the circumference of starch granules. Aggregate and elongated granules had higher amylose content than individual granules. Elongated and individual granules had the highest and the lowest gelatinization resistance among high-amylose maize heterogeneous starch granules, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Role of genetic resources from different geographic and climatic regions in simultaneous breeding for high quality protein maize (HQPM and stress tolerance

    Directory of Open Access Journals (Sweden)

    Denic Miloje

    2012-01-01

    Full Text Available Due to the low biological value of proteins of common maize, it was reinitiated breeding for high protein quality maize (HQPM using three genetic systems, namely: opaque-2 gene, endosperm modifier genes and enhancer genes, which are increasing lysine and tryptophan content in opaque-2 background In order to alleviate effect of abiotic and biotic stress factors, the genotypes with tolerance to those factors were included. Genetic resources originating from North, Central and South America, then West, Central and Southern Africa and gene bank of Maize Research Institute “Zemun Polje” were used. Combining breeding approaches in selection of genetic resources, field plot techniques and laboratory analysis, it was created large number of early QPM varieties, inbred lines and hybrids with modified endosperm and high yield potential under poor and good growing conditions. Created lines exhibited high combining ability in conventional and non-conventional hybrids. Yield trials showed that QPM hybrids are competing with commercial hybrids of common maize.

  11. In Vitro Biochemical Characterization of All Barley Endosperm Starch Synthases

    Directory of Open Access Journals (Sweden)

    Jose Antonio Cuesta-Seijo

    2016-01-01

    Full Text Available Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs. While the overall starch synthase (SS reaction is known, the functional differences between the five SS classes are poorly understood. Much of our knowledge comes from analyzing mutant plants with altered SS activities, but the resulting data are often difficult to interpret as a result of pleitropic effects, competition between enzymes, overlaps in enzyme activity and disruption of multi-enzyme complexes. Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results define the mode of action of each SS class in unprecedented detail; we analyze their substrate selection, temperature dependence and stability, substrate affinity and temporal abundance during barley development. Our results are at variance with some generally accepted ideas about starch biosynthesis and might lead to the reinterpretation of results obtained in planta. In particular, they indicate that granule bound SS is capable of processive action even in the absence of a starch matrix, that SSI has no elongation limit, and that SSIV, believed to be critical for the initiation of starch granules, has maltoligosaccharides and not polysaccharides as its preferred substrates.

  12. Lipid composition of organelles from germinating castor bean endosperm

    Energy Technology Data Exchange (ETDEWEB)

    Donaldson, R.P.; Beevers, H.

    1977-02-01

    Glyoxysome, endoplasmic reticulum, mitochondria, and proplastid fractions were isolated from endosperm of castor beans (Ricinus communis) germinated for 5 days at 30 C. Samples from sucrose density gradients were diluted with 0.15 M KCl and the membranes pelleted. Lipid extracts of these membranes were analyzed for phosphoglyceride, acyl lipid, and sterol content. The endoplasmic reticulum contains 1.24 ..mu..mol of phosphoglyceride per mg of protein; the mitochondria, 0.65 ..mu..mol/mg; and the glyoxysome membranes, 0.55 ..mu..mol/mg. Phosphatidyl choline and phosphatidyl ethanolamine are the most abundant lipids in all membranes studied, accounting for 70% or more of the lipid phosphorus and 50% or more of the fatty acid. Glyoxysome membranes and endoplasmic reticulum also contain phosphatidyl inositol (respectively, 9 and 17% of the lipid phosphorus) and free fatty acids (13% of the total fatty acid in each). Compared with other organelles, mitochondrial membranes have more phosphatidyl ethanolamine relative to phosphatidyl choline and are characterized by the presence of cardiolipin, in which 80% of the fatty acid is linoleate. The relative amounts of linoleate, palmitate, oleate, stearate, and linolenate in each of the phosphotoglycerides are constant regardless of the membrane source. Stimasgasterol and ..beta..-sitosterol are present in the membranes (1 to 9 nmol each/mg protein). The data provide further evidence that glyoxysome membranes are derived from the endoplasmic reticulum but at the same time indicate some differentiation.

  13. Prevalence of genetically modified rice, maize, and soy in Saudi food products.

    Science.gov (United States)

    Elsanhoty, Rafaat M; Al-Turki, A I; Ramadan, Mohamed Fawzy

    2013-10-01

    Qualitative and quantitative DNA-based methods were applied to detect genetically modified foods in samples from markets in the Kingdom of Saudi Arabia. Two hundred samples were collected from Al-Qassim, Riyadh, and Mahdina in 2009 and 2010. GMOScreen 35S and NOS test kits for the detection of genetically modified organism varieties in samples were used. The positive results obtained from GMOScreen 35S and NOS were identified using specific primer pairs. The results indicated that all rice samples gave negative results for the presence of 35S and NOS terminator. About 26 % of samples containing soybean were positive for 35S and NOS terminator and 44 % of samples containing maize were positive for the presence of 35S and/or NOS terminator. The results showed that 20.4 % of samples was positive for maize line Bt176, 8.8 % was positive for maize line Bt11, 8.8 % was positive for maize line T25, 5.9 % was positive for maize line MON 810, and 5.9 % was positive for StarLink maize. Twelve samples were shown to contain genetically modified (GM) soy and 6 samples >10 % of GM soy. Four samples containing GM maize were shown to contain >5 % of GM maize MON 810. Four samples containing GM maize were shown to contain >1 % of StarLink maize. Establishing strong regulations and certified laboratories to monitor GM foods or crops in Saudi market is recommended.

  14. The Maize Imprinted Gene Floury3 Encodes a PLATZ Protein Required for tRNA and 5S rRNA Transcription Through Interaction with RNA Polymerase III.

    Science.gov (United States)

    Li, Qi; Wang, Jiechen; Ye, Jianwei; Zheng, Xixi; Xiang, Xiaoli; Li, Changsheng; Fu, Miaomiao; Wang, Qiong; Zhang, Zhi-Yong; Wu, Yongrui

    2017-09-05

    Maize (Zea mays) floury3 (fl3) is a classic semi-dominant negative mutant that exhibits severe defects in the endosperm but fl3 plants otherwise appear normal. We cloned the fl3 gene and determined that it encodes a PLATZ (plant AT-rich sequence- and zinc-binding) protein. The mutation in fl3 resulted in an Asn to His replacement in the conserved PLATZ domain, creating a dominant allele. Fl3 is specifically expressed in starchy endosperm cells and regulated by genomic imprinting, which leads to the suppressed expression of fl3 when transmitted through the male, perhaps as a consequence the semi-dominant behavior. Yeast two-hybrid screening and bimolecular luciferase complementation (BiLC) experiments revealed that FL3 interacts with the RNA polymerase III subunit 53 (RPC53) and transcription factor class C 1 (TFC1), two critical factors of the RNA polymerase III (RNAPIII) transcription complex. In the fl3 endosperm, the levels of many tRNAs and 5S rRNA that are transcribed by RNAPIII are significantly reduced, suggesting that the incorrectly folded fl3 protein may impair the function of RNAPIII. The transcriptome is dramatically altered in fl3 mutants, in which the down-regulated genes are primarily enriched in pathways related to translation, ribosome, misfolded protein responses and nutrient reservoir activity. Collectively, these changes may lead to defects in endosperm development and storage reserve filling in fl3 seeds. © 2017 American Society of Plant Biologists. All rights reserved.

  15. A comparative study on the role of cytokinins in caryopsis development in the maize miniature1 seed mutant and its wild type.

    Science.gov (United States)

    Rijavec, Tomaz; Kovac, Maja; Kladnik, Ales; Chourey, Prem S; Dermastia, Marina

    2009-09-01

    We report here on a comparative developmental profile of plant hormone cytokinins in relation to cell size, cell number and endoreduplication in developing maize caryopsis of a cell wall invertase-deficient miniature1 (mn1) seed mutant and its wild type, Mn1, genotype. Both genotypes showed extremely high levels of total cytokinins during the very early stages of development, followed by a marked and genotype specific reduction. While the decrease of cytokinins in Mn1 was associated with their deactivation by 9-glucosylation, the absolute and the relative part of active cytokinin forms was higher in the mutant. During the exponential growth phase of endosperm between 6 d after pollination and 9 d after pollination, the mean cell doubling time, the absolute growth rate and the level of endoreduplication were similar in the two genotypes. However, the entire duration of growth was longer in Mn1 compared with mn1, resulting in a significantly higher cell number in the Mn1 endosperm. These data correlate with the previously reported peak levels of the Mn1-encoded cell wall invertase-2 (INCW2) at 12 d after pollination in the Mn1 endosperm. A model showing possible crosstalk among cytokinins, cell cycle and cell wall invertase as causal to increased cell number and sink strength of the Mn1 developing endosperm is discussed.

  16. Chromosomal loci associated with endosperm hardness in a malting barley cross.

    Science.gov (United States)

    Walker, Cassandra K; Panozzo, J F; Ford, R; Eckermann, P; Moody, D; Lehmensiek, A; Appels, R

    2011-01-01

    A breeding objective for the malting barley industry is to produce lines with softer, plumper grain containing moderate protein content (9-12%) as they are more likely to imbibe water readily and contain more starch per grain, which in turn produces higher levels of malt extract. In a malting barley mapping population, 'Arapiles' × 'Franklin', the most significant and robust quantitative trait locus (QTL) for endosperm hardness was observed on the short arm of chromosome 1H, across three environments over two growing seasons. This accounted for 22.6% (Horsham 2000), 26.8% (Esperance 2001), and 12.0% (Tarranyurk 2001) of the genetic variance and significantly increased endosperm hardness by 2.06-3.03 SKCS hardness units. Interestingly, Arapiles and Franklin do not vary in Ha locus alleles. Therefore, this region, near the centromere on chromosome 1H, may be of great importance when aiming to manipulate endosperm hardness and malting quality. Interestingly, this region, close to the centromere on chromosome 1H, in our study, aligns with the region of the genome that includes the HvCslF9 and the HvGlb1 genes. Potentially, one or both of these genes could be considered to be candidate genes that influence endosperm hardness in the barley grain. Additional QTLs for endosperm hardness were detected on chromosomes 2H, 3H, 6H and 7H, confirming that the hardness trait in barley is complex and multigenic, similar to many malting quality traits of interest.

  17. Control of fertilization-independent endosperm development by the MEDEA polycomb gene in Arabidopsis.

    Science.gov (United States)

    Kiyosue, T; Ohad, N; Yadegari, R; Hannon, M; Dinneny, J; Wells, D; Katz, A; Margossian, L; Harada, J J; Goldberg, R B; Fischer, R L

    1999-03-30

    Higher plant reproduction is unique because two cells are fertilized in the haploid female gametophyte. Egg and sperm nuclei fuse to form the embryo. A second sperm nucleus fuses with the central cell nucleus that replicates to generate the endosperm, a tissue that supports embryo development. To understand mechanisms that initiate reproduction, we isolated a mutation in Arabidopsis, f644, that allows for replication of the central cell and subsequent endosperm development without fertilization. When mutant f644 egg and central cells are fertilized by wild-type sperm, embryo development is inhibited, and endosperm is overproduced. By using a map-based strategy, we cloned and sequenced the F644 gene and showed that it encodes a SET-domain polycomb protein. Subsequently, we found that F644 is identical to MEDEA (MEA), a gene whose maternal-derived allele is required for embryogenesis [Grossniklaus, U., Vielle-Calzada, J.-P., Hoeppner, M. A. & Gagliano, W. B. (1998) Science 280, 446-450]. Together, these results reveal functions for plant polycomb proteins in the suppression of central cell proliferation and endosperm development. We discuss models to explain how polycomb proteins function to suppress endosperm and promote embryo development.

  18. Study on Plant Regeneration of Wheat Mature Embryos Under Endosperm-Supported Culture

    Institute of Scientific and Technical Information of China (English)

    CHEN Jun-ying; YUE Run-qing; XU Hai-xian; CHEN Xin-jian

    2006-01-01

    To reveal the suitability of using mature embryos as an explant source in wheat tissue culture, mature embryos from eight common wheat cultivars (Triticum aestivum L. cv.) were cultured with or without endosperm to test their efficiency of callus induction and plant regeneration. When embryos were cultured together with endosperm (endosperm-supported culture, ES), the percentage of callus induction was significantly lower than that when embryos were cultured in the absence of endosperm (non-endosperm-supported culture, NES). This pattern was evident in most genotypes, regardless of whether 2 or 8 mg L-1 2,4-D was added in the NES culture. However, in ES culture, more induced calli were differentiated into distinct green spots and they further developed into plantlets. Thus, more plants were regenerated in ES culture than in the NES treatment. Most of the eight tested genotypes showed a significant difference in callus induction rate and plantlet regeneration in both ES and NES cultures. In addition, the enzymatic activity of oxalate oxidase in the callus of ES culture condition was obviously higher than that in the callus of NES culture condition, suggesting that the activity of oxalate oxidase may be a parameter for selection of calli with potential for plantlet regeneration. These results indicate that wheat mature embryos are valuable explants for highly efficient callus induction and plant regeneration, if proper treatment and medium are used.

  19. Contrast observation and investigation of wheat endosperm transfer cells and nucellar projection transfer cells.

    Science.gov (United States)

    Zheng, Yankun; Wang, Zhong

    2011-07-01

    In cereal seed, there are no symplastic connections between the maternal tissues and the endosperm. In order to facilitate solute transport, both the nucellar projection and its opposite endosperm epithelial cells in wheat caryopsis differentiate into transfer cells. In this paper, we did contrast observation and investigation of wheat endosperm transfer cells (ETC) and nucellar projection transfer cells (NPTC). The experimental results showed that there were some similarities and differences between ETC and NPTC. ETC and NPTC almost developed synchronously. Wall ingrowths of ETC and NPTC formed firstly in the first layer nearest to the endosperm cavity, and formed later in the inner layer further from the endosperm cavity. The mature ETC were mainly three layers and the mature NPTC were mainly four layers. Wall ingrowths of ETC were flange type and wall ingrowths of NPTC were reticulate type. NPTC were not nutrient-storing cells, but the first layer of ETC had aleurone cell features, and the second layer and third layer of ETC accumulated starch granules and protein bodies.

  20. A comparison of controlled self-pollination and open pollination results based on maize grain quality

    Directory of Open Access Journals (Sweden)

    Hanna Sulewska

    2014-05-01

    Full Text Available Maize (Zea mays L. grain endosperm is triploid (3n, of which 2n come from the male (transferred by pollen and only 1n from the female plant, thus a major impact of the male form can be expected on grain quality parameters. A good example of this relationship is the phenomenon of xenia. The aim of this study was to determine the effect of pollen on grain quality. The field experiment was conducted in 2011; seeds were harvested from eight cultivars: Bosman, Blask, Tur, Kozak, Bielik, Smok, SMH 220 and Kresowiak, derived from free pollination and controlled self-pollination of maize. Analyses of nutrient contents and starch content in the grain were conducted in the laboratory. In addition, 1000 grain weight and the hectoliter weight of all grain samples were recorded. The results confirmed differences in grain quality of maize hybrids obtained by self-pollination and by open pollination. Grain of maize plants obtained by open-pollination was characterised by higher contents of N-free extract and starch, and lower protein content. Undertaking further studies on this subject may indicate specific recommendations for agricultural practice, such as mixtures of hybrids with good combining abilities, which will contribute to improved grain quality without additional costs.

  1. Abscisic acid controls embryo growth potential and endosperm cap weakening during coffee (Coffea arabica cv. Rubi) seed germination

    NARCIS (Netherlands)

    Silva, da E.A.A.; Toorop, P.E.; Aelst, van A.C.; Hilhorst, H.W.M.

    2004-01-01

    The mechanism and regulation of coffee seed germination were studied in Coffea arabica L. cv. Rubi. The coffee embryo grew inside the endosperm prior to radicle protrusion and abscisic acid (ABA) inhibited the increase in its pressure potential. There were two steps of endosperm cap weakening. An in

  2. Abscisic acid controls embryo growth potential and endosperm cap weakening during coffee (Coffea arabica cv. Rubi) seed germination

    NARCIS (Netherlands)

    Silva, da E.A.A.; Toorop, P.E.; Aelst, van A.C.; Hilhorst, H.W.M.

    2004-01-01

    The mechanism and regulation of coffee seed germination were studied in Coffea arabica L. cv. Rubi. The coffee embryo grew inside the endosperm prior to radicle protrusion and abscisic acid (ABA) inhibited the increase in its pressure potential. There were two steps of endosperm cap weakening. An in

  3. MaizeGDB, the community database for maize genetics and genomics

    OpenAIRE

    2004-01-01

    The Maize Genetics and Genomics Database (MaizeGDB) is a central repository for maize sequence, stock, phenotype, genotypic and karyotypic variation, and chromosomal mapping data. In addition, MaizeGDB provides contact information for over 2400 maize cooperative researchers, facilitating interactions between members of the rapidly expanding maize community. MaizeGDB represents the synthesis of all data available previously from ZmDB and from MaizeDB—databases that have been superseded by Maiz...

  4. Isolation and Translation of Hordein Messenger RNA from Wild Type and Mutant Endosperms in Barley

    DEFF Research Database (Denmark)

    Brandt, Anders Bøving; Ingwersen, J.

    1978-01-01

    Nucleotide sequences of four cDNA clones coding for the carboxy-terminal portion of at least two different B1 hordein polypeptides are presented. The open reading frame in the nucleotide sequence of the the largest clone (pc hor2-4, 720 nucleotides) translates into the 181 carboxy-terminal amino...... was found to be a major constituent of the total messenger RNA population of the endosperm cell. Polyadenylated hordein messenger RNA sedimented at 11S in sucrose gradients and electrophoretic analysis reveals the presence of at least three RNA species with apparent molecular weights of 0.45, 0.36 and 0.......30 megadaltons. The 11S messenger RNA was translated in vitro into hordein precursor polypeptides which are 2–4 kilodaltons larger than the native hordein polypeptides. The endosperm cell of mutant No. 1508 contained twice as much RNA as the wild type endosperm cell but the same amount of polyadenylated 11S RNA...

  5. Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose A.; Ruzanski, Christian; Krucewicz, Katarzyna

    2017-01-01

    (HvPho1) for starch biosynthesis in barley endosperm, we analyzed HvPho1 protein production and enzyme activity levels throughout barley endosperm development and characterized structure-function relationships of HvPho1. The molecular mechanisms underlying the initiation of starch granule biosynthesis......The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose...... and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1...

  6. Carotenoids of aleurone, germ, and endosperm fractions of barley, corn and wheat differentially inhibit oxidative stress.

    Science.gov (United States)

    Masisi, Kabo; Diehl-Jones, William L; Gordon, Joseph; Chapman, Donald; Moghadasian, Mohammed H; Beta, Trust

    2015-03-18

    The antioxidant potential of carotenoids from aleurone, germ, and endosperm fractions of barley, corn, and wheat has been evaluated. HPLC analysis confirmed the presence of lutein and zeaxanthin carotenoids (nd-15139 μg/kg) in extracts of cereal grain fractions. The antioxidant properties using 2,2-diphenyl-1-picrylhydrazyl, oxygen radical absorbance capacity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) assays revealed significantly higher (Paleurone and endosperm fractions. Using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, 2,2'azobis (2-amidinopropane)dihydrochloride (AAPH)-induced cell loss was effectively reduced by preincubating Caco-2, HT-29, and FHs 74 Int cells with carotenoid extracts. Moreover, carotenoid extracts reduced (Paleurone, and endosperm fractions improved antioxidant capacity and thus have the potential to mitigate oxidative stress.

  7. Maize microarray annotation database

    Directory of Open Access Journals (Sweden)

    Berger Dave K

    2011-10-01

    Full Text Available Abstract Background Microarray technology has matured over the past fifteen years into a cost-effective solution with established data analysis protocols for global gene expression profiling. The Agilent-016047 maize 44 K microarray was custom-designed from EST sequences, but only reporter sequences with EST accession numbers are publicly available. The following information is lacking: (a reporter - gene model match, (b number of reporters per gene model, (c potential for cross hybridization, (d sense/antisense orientation of reporters, (e position of reporter on B73 genome sequence (for eQTL studies, and (f functional annotations of genes represented by reporters. To address this, we developed a strategy to annotate the Agilent-016047 maize microarray, and built a publicly accessible annotation database. Description Genomic annotation of the 42,034 reporters on the Agilent-016047 maize microarray was based on BLASTN results of the 60-mer reporter sequences and their corresponding ESTs against the maize B73 RefGen v2 "Working Gene Set" (WGS predicted transcripts and the genome sequence. The agreement between the EST, WGS transcript and gDNA BLASTN results were used to assign the reporters into six genomic annotation groups. These annotation groups were: (i "annotation by sense gene model" (23,668 reporters, (ii "annotation by antisense gene model" (4,330; (iii "annotation by gDNA" without a WGS transcript hit (1,549; (iv "annotation by EST", in which case the EST from which the reporter was designed, but not the reporter itself, has a WGS transcript hit (3,390; (v "ambiguous annotation" (2,608; and (vi "inconclusive annotation" (6,489. Functional annotations of reporters were obtained by BLASTX and Blast2GO analysis of corresponding WGS transcripts against GenBank. The annotations are available in the Maize Microarray Annotation Database http://MaizeArrayAnnot.bi.up.ac.za/, as well as through a GBrowse annotation file that can be uploaded to

  8. Proteomic analysis reveals differential accumulation of small heat shock proteins and late embryogenesis abundant proteins between ABA-deficient mutant vp5 seeds and wild-type Vp5 seeds in maize

    Directory of Open Access Journals (Sweden)

    Xiaolin eWu

    2015-01-01

    Full Text Available ABA is a major plant hormone that plays important roles during many phases of plant life cycle, including seed development, maturity and dormancy, and especially the acquisition of desiccation tolerance. Understanding of the molecular basis of ABA-mediated plant response to stress is of interest not only in basic research on plant adaptation but also in applied research on plant productivity. Maize mutant viviparous-5 (vp5, deficient in ABA biosynthesis in seeds, is a useful material for studying ABA-mediated response in maize. Due to carotenoid deficiency, vp5 endosperm is white, compared to yellow Vp5 endosperm. However, the background difference at proteome level between vp5 and Vp5 seeds is unclear. This study aimed to characterize proteome alterations of maize vp5 seeds and to identify ABA-dependent proteins during seed maturation. We compared the embryo and endosperm proteomes of vp5 and Vp5 seeds by gel-based proteomics. Up to 46 protein spots, most in embryos, were found to be differentially accumulated between vp5 and Vp5. The identified proteins included small heat shock proteins (sHSPs, late embryogenesis abundant (LEA proteins, stress proteins, storage proteins and enzymes among others. However, EMB564, the most abundant LEA protein in maize embryo, accumulated in comparable levels between vp5 and Vp5 embryos, which contrasted to previously characterized, greatly lowered expression of emb564 mRNA in vp5 embryos. Moreover, LEA proteins and sHSPs displayed differential accumulations in vp5 embryos: six out of eight identified LEA proteins decreased while nine sHSPs increased in abundance. Finally, we discussed the possible causes of global proteome alterations, especially the observed differential accumulation of identified LEA proteins and sHSPs in vp5 embryos. The data derived from this study provides new insight into ABA-dependent proteins and ABA-mediated response during maize seed maturation.

  9. Breeding of speciality maize for industrial purposes

    OpenAIRE

    2010-01-01

    The breeding programme on speciality maize with specific traits was established at the Maize Research Institute, Zemun Polje, several decades ago. The initial material was collected, new methods applying to breeding of speciality maize, i.e. popping maize, sweet maize and white-seeded maize, were introduced. The aim was to enhance and improve variability of the initial material for breeding these three types of maize. Then, inbred lines of good combining abilities were developed and used as c...

  10. Proteomic analysis of rice endosperm cells in response to expression of hGM-CSF.

    Science.gov (United States)

    Luo, Junling; Ning, Tingting; Sun, Yunfang; Zhu, Jinghua; Zhu, Yingguo; Lin, Qishan; Yang, Daichang

    2009-02-01

    The accumulation of significant levels of transgenic products in plant cells is required not only for crop improvement, but also for molecular pharming. However, knowledge about the fate of transgenic products and endogenous proteins in grain cells is lacking. Here, we utilized a quantitative mass spectrometry-based proteomic approach for comparative analysis of expression profiles of transgenic rice endosperm cells in response to expression of a recombinant pharmaceutical protein, human granulocyte-macrophage colony stimulation factor (hGM-CSF). This study provided the first available evidence concerning the fate of exogenous and endogenous proteins in grain cells. Among 1883 identified proteins with a false positive rate of 5%, 103 displayed significant changes (p-value < 0.05) between the transgenic and the wild-type endosperm cells. Notably, endogenous storage proteins and most carbohydrate metabolism-related proteins were down-regulated, while 26S proteasome-related proteins and chaperones were up-regulated in the transgenic rice endosperm. Furthermore, it was observed that expression of hGM-CSF induced endoplasmic reticulum stress and activated the ubiquitin/26S-proteasome pathway, which led to ubiquitination of this foreign gene product in the transgenic rice endosperm.

  11. DNA endoreplication level in endosperm and in cotyledons during seed development in three dicotyledonous species

    Directory of Open Access Journals (Sweden)

    Kazimierz Marciniak

    2014-01-01

    Full Text Available The DNA content of nuclear and cellular endosperm and in cotyledons in the course of seed development in Helianthus annuus, Pisum sativum and Vicia faba was cytophotometrically measured after Faulgen's reaction. Helianthus annuus is characterized by the lowest endoreplication dynamics attaining a maximum DNA content of 48C in nuclear endosperm, which corresponds to four endoreplication rounds, and 16C DNA (three rounds in cotyledons. In Pisum sativum cellular endosperm in the studied stages of seed development was absent and the highest DNA content in cotyledons was 512C DNA; this corresponds to eight endoreplication rounds. In Vicia faba, the maximum DNA endoreplication level was 1536C in nuclear endosperm, which corresponds to nine endoreplication rounds; in cotyledons the maximum DNA content was 64C (five rounds. In the course of seed development, differences in the dynamics of DNA endoreplication in throphic tissues of the examined species seem to be similar to differences in the endoreplication level in root and leaf parenchyma, but the DNA endoreplication level is much higher in throphic tissues. Therefore, the endoreplication pattern might be species-specific and genetically conditioned.

  12. Influence of instrument rigidity and specimen geometry on calculations of compressive strength properties of wheat endosperm

    Science.gov (United States)

    Endosperm texture is one of the most important quality features in wheat that defines milling energy requirements and the suitability of flour or semolina for the various food products such as pan breads, crackers, cakes, and pastas. Rooted in low molecular weight proteins known as puroindolines a a...

  13. The 75% Isopropanol-Soluble Polysaccharides from the Endosperm of the Legume Seed of Gleditsia Triacanthos

    Directory of Open Access Journals (Sweden)

    Carlos A. Stortz

    2000-03-01

    Full Text Available The 75% isopropanol-soluble material from the endosperm of the legume-seed of Gleditsia triacanthos was isolated. The material extracted with boiling water was fractionated by ion-exchange chromatography and characterized. Besides minor amounts of galactomannans, major proportions of arabinans and/or arabinogalactans appear.

  14. Purification and characterization of a serine protease (CESP from mature coconut endosperm

    Directory of Open Access Journals (Sweden)

    Mandal Chhabinath

    2009-05-01

    Full Text Available Abstract Background In plants, proteases execute an important role in the overall process of protein turnover during seed development, germination and senescence. The limited knowledge on the proteolytic machinery that operates during seed development in coconut (Cocos nucifera L. prompted us to search for proteases in the coconut endosperm. Findings We have identified and purified a coconut endosperm protease (CESP to apparent homogeneity. CESP is a single polypeptide enzyme of approximate molecular mass of 68 kDa and possesses pH optimum of 8.5 for the hydrolysis of BAPNA. Studies relating to substrate specificity and pattern of inhibition by various protease inhibitors indicated that CESP is a serine protease with cleavage specificity to peptide bonds after arginine. Purified CESP was often autolysed to two polypeptides of 41.6 kDa (CESP1 and 26.7 kDa (CESP2 and is confirmed by immunochemistry. We have shown the expression of CESP in all varieties of coconut and in all stages of coconut endosperm development with maximum amount in fully matured coconut. Conclusion Since the involvement of proteases in the processing of pre-proteins and maintenance of intracellular protein levels in seeds are well known, we suspect this CESP might play an important role in the coconut endosperm development. However this need to be confirmed using further studies.

  15. Widespread Contamination of Arabidopsis Embryo and Endosperm Transcriptome Data Sets[OPEN

    Science.gov (United States)

    2017-01-01

    A major goal of global gene expression profiling in plant seeds has been to investigate the parental contributions to the transcriptomes of early embryos and endosperm. However, consistency between independent studies has been poor, leading to considerable debate. We have developed a statistical tool that reveals the presence of substantial RNA contamination from maternal tissues in nearly all published Arabidopsis thaliana endosperm and early embryo transcriptomes generated in these studies. We demonstrate that maternal RNA contamination explains the poor reproducibility of these transcriptomic data sets. Furthermore, we found that RNA contamination from maternal tissues has been repeatedly misinterpreted as epigenetic phenomena, which has resulted in inaccurate conclusions regarding the parental contributions to both the endosperm and early embryo transcriptomes. After accounting for maternal RNA contamination, no published genome-wide data set supports the concept of delayed paternal genome activation in plant embryos. Moreover, our analysis suggests that maternal and paternal genomic imprinting are equally rare events in Arabidopsis endosperm. Our publicly available software (https://github.com/Gregor-Mendel-Institute/tissue-enrichment-test) can help the community assess the level of contamination in transcriptome data sets generated from both seed and non-seed tissues. PMID:28314828

  16. Programmed cell death or desiccation tolerance : two possible routes for wheat endosperm cells

    NARCIS (Netherlands)

    Golovina, E.A.; Hoekstra, F.A.; Aelst, van A.C.

    2000-01-01

    The fate of cells in the endosperm of developing wheat kernels was investigated under normal conditions and upon premature slow drying on the cut ear. To follow the changes in membrane integrity and cellular ultrastructure, an electron spin resonance (ESR) spin probe technique and low temperature sc

  17. Primer Dependent and Independent Forms of Soluble Starch Synthetase from Developing Barley Endosperms

    DEFF Research Database (Denmark)

    Kreis, M.

    1980-01-01

    The activity of soluble starch synthetase (ADP-glucose: agr-1,4-glucan agr-4-glucosyltransferase) in the non-purified extract from 16 day-old Bomi barley endosperms (Hordeum vulgare L.) was low and the reaction was non-linear when plotted against protein concentration. Starch synthetase was purif...

  18. Fertilization in Torenia fournieri: actin organization and nuclear behavior in the central cell and primary endosperm

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Studies of the living embryo sacs of Torenia fournieri reveal that the actin cytoskeleton undergoes dramatic changes that correlate with nuclear migration within the central cell and the primary endosperm. Before pollination, actin filaments appear as short bundles randomly distributed in the cortex of the central cell. Two days after anthesis, they become organized into a distinct actin network. At this stage the secondary nucleus, which is located in the central region of the central cell, possesses an associated array of short actin filaments. Soon after pollination, the actin filaments become fragmented in the micropylar end and the secondary nucleus is located next to the egg apparatus. After fertilization, the primary endosperm nucleus moves away from the egg cell and actin filaments reorganize into a prominent network in the cytoplasm of the primary endosperm. Disruption of the actin cytoskeleton with latrunculin A and cytochalasin B indicates that actin is involved in the migration of the nucleus in the central cell. Our data also suggest that the dynamics of actin cytoskeleton may be responsible for the reorganization of the central cell and primary endosperm cytoplasm during fertilization.

  19. Reorganization of microtubular cytoskeleton and formation of cellular processes during post-telophase in haemanthus endosperm.

    Science.gov (United States)

    Bajer, A S; Smirnova, E A

    1999-10-01

    We followed time-dependent post-telophase reorganization of the microtubule cytoskeleton on immunostained preparations of endosperm of the higher plant Haemanthus. After completion of mitosis, the phragmoplast continued to reorganize for several hours. This prompted the formation of phragmoplast-like derivatives (secondary and accessory phragmoplasts and peripheral microtubular ring). Next, elongated cellular protrusions (processes) appeared at the cell periphery. These processes contained long microtubule bundles and disorderly arranged actin filaments. Microtubule converging centers or accessory phragmoplasts were often present at the tips of the processes. Observation in vivo demonstrated that processes were formed at the cell periphery as extensions of lammelipodia or filopodia-type protrusions that commonly terminated with cytoplasmic blobs. We suggest that processes are derivatives of a peripheral microtubular ring that reorganizes gradually into cellular protrusions. Endosperm processes have several features of neuronal cells, or animal somatic cells with overexpressed MAPs. Since microtubule-containing processes were never detected shortly after extrusion of the cells from the embryo sac, this course of events might be restricted specifically to extruded endosperm and triggered either by removal of cells, their placement in monolayer on agar substrate, or both. Thus, post telophase behavior of endosperm cells offers a novel experimental system for studies of cytoskeleton in higher plants.

  20. Proteomics of Wheat Endosperm: a Tool to Find Genes Involved in Kernel Composition and Quality

    Institute of Scientific and Technical Information of China (English)

    G. Branlard; E. Bancel; I. Nadaud

    2007-01-01

    @@ The composition of the wheat kernel is the result of the expression of thousands of genes translated in enzymes involved in all the biochemical pathways that are needed for endosperm cell functions and also for the accumulation of storage proteins and starch.

  1. EFFECT OF PHYSIOLOGICAL AGE AND GROWTH REGULATORS ON CALLUS BROWNING OF COCONUT ENDOSPERM CULTURE IN VITRO

    Directory of Open Access Journals (Sweden)

    LAZARUS AGUS SUKAMTO

    2011-01-01

    Full Text Available The possibility of physiological age and growth regulators affecting callus browning ofcoconut endosperm was investigated. Solid endosperm explants of four coconut fruits fromsame brunches of two coconut cultivars “Samoan Dwarf ” were grown on modified Murashigeand Skoog (MS formula with addition of 10 mg l putresine, 2.50 g l activated charcoal (AC,1.70 g l phytagel, 0, 10 , 10 , 10 , 10 M 2,4-dichlorophenoxyacetic acid (2,4-D or 4-amino-3,5,6-trichloropicolinic acid (Picloram combined with 10 M 6-benzylaminopurine (BA.Callogenesis occurred on 98.83% of explants. Callus browning between different physiologicalages (antipodal and micropylar tissues of coconut endosperm at 9, 26 and 31 weeks of culture(WOC was significantly different, but not at 16 and 21 WOC. Auxins of 2,4-D and Picloramdid not affect significantly callus browning of endosperm cultures. Auxin doses at 10 , 10 , and10 M decreased significantly callus browning at 9 and 16 WOC, respectively, but at 10 Mbrowning was less significant compared to other doses at 21 WOC. Auxin dose at 10 M causedless significant browning compared to other doses at 31 WOC. The addition of BA decreasedsignificantly callus browning at 9 WOC, but did not affect callus browning thereafter.

  2. Physicochemical and Sensory Properties of Boiled Prosopis africana Seed Endosperm Macerated in Various Ethanol-water Mixtures

    Directory of Open Access Journals (Sweden)

    James E. Obiegbuna

    2013-09-01

    Full Text Available The processing of boiled Prosopis africana endosperm for better utilization using ethanol-water mixtures was explored. Prosopis africana seeds were boiled for 5 h to softness and the endosperm fraction separated from the kernel (cotyledon and the hull. The endosperm was divided into five equal parts which were individually macerated in absolute (Abs ethanol, 80, 60 and 40% ethanol in water prior to sun-drying (32±2°C, 3 days. The fifth sample, which served as control, was left untreated with ethanol. The samples were ground using a hand milling machine and analyzed for the proximate composition, water and oil absorption capacities, foaming capacity and foam stability, bulk density, emulsion activity and stability, colour preference, texture preference and overall acceptability. The results revealed that treatment of the endosperm significantly affected the moisture, protein, fat, ash and carbohydrate contents; water and oil absorption capacities, foaming capacity and foam stability; and the sensory properties. The moisture and protein contents, oil absorption capacity, foam stability, appearance, texture and overall acceptability of endosperm treated with 40% ethanol in water differed significantly (p<0.05 from that treated with absolute ethanol. There was also significant (p<0.05 differences in moisture, protein and carbohydrate contents, oil absorption capacity and foam stability of the 40% ethanol in water treated endosperm and the control. Slightly above 40% ethanol in water (50-60% should be used to macerate Prosopis africana endosperm to reduce the cost of using absolute ethanol.

  3. Characterization of the endosperm starch and the pleiotropic effects of biosynthetic enzymes on their properties in novel mutant rice lines with high resistant starch and amylose content.

    Science.gov (United States)

    Itoh, Yuuki; Crofts, Naoko; Abe, Misato; Hosaka, Yuko; Fujita, Naoko

    2017-05-01

    Resistant starch (RS) is beneficial to human health. In order to reduce the current prevalence of diabetes and obesity, several transgenic and mutant crops containing high RS content are being developed. RS content of steamed rice with starch-branching enzyme (BE)IIb-deficient mutant endosperms is considerably high. To understand the mechanisms of RS synthesis and to increase RS content, we developed novel mutant rice lines by introducing the gene encoding starch synthase (SS)IIa and/or granule-bound starch synthase (GBSS)I from an indica rice cultivar into a japonica rice-based BEIIb-deficient mutant line, be2b. Introduction of SSIIa from an indica rice cultivar produced higher levels of amylopectin chains with degree of polymerization (DP) 11-18 than those in be2b; the extent of the change was slight due to the shortage of donor chains for SSIIa (DP 6-12) owing to BEIIb deficiency. The introduction of GBSSI from an indica rice cultivar significantly increased amylose content (by approximately 10%) in the endosperm starch. RS content of the new mutant lines was the same as or slightly higher than that of the be2b parent line. The relationship linking starch structure, RS content, and starch biosynthetic enzymes in the new mutant lines has also been discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Transferring Translucent Endosperm Mutant Gene Wx-mq and Rice Stripe Disease Resistance Gene Stv-bi by Marker-Assisted Selection in Rice (Oryza sativa)

    Institute of Scientific and Technical Information of China (English)

    YAO Shu; CHEN Tao; ZHANG Ya-dong; ZHU Zhen; ZHAO Ling; ZHAO Qing-yong; ZHOU Li-hui; WANG Cai-lin

    2011-01-01

    A high-yielding japonica rice variety,Wuyunjing 7,bred in Jiangsu Province,China as a female parent was crossed with a Japanese rice variety Kantou 194,which carries a rice stripe disease resistance gene Stv-b1 and a translucent endosperm mutant gene Wx-mq.From F2 generations,a sequence characterized amplified region (SCAR) marker tightly linked with Stv-b1 and a cleaved amplified polymorphic sequence (CAPS) marker for Wx-mq were used for marker-assisted selection.Finally,a new japonica rice line,Ning 9108,with excellent agronomic traits was obtained by multi-generational selection on stripe disease resistance and endosperm appearance.The utilization of the markers from genes related to rice quality and disease resistance was helpful not only for establishing a marker-assisted selection system of high-quality and disease resistance for rice but also for providing important intermediate materials and rapid selection method for good quality,disease resistance and high yield in rice breeding.

  5. Preparation and Properties of Cross-linking and Esterifying Pregelatinization Starch of Mechanical Activated Maize Starch%交联酯化机械活化玉米复合变性淀粉的制备及其性能研究

    Institute of Scientific and Technical Information of China (English)

    杨家添; 陈渊; 朱万仁; 谭义秋; 黄祖强; 黎宏妃

    2012-01-01

    以机械活化玉米淀粉为原料,三偏磷酸钠为交联剂,醋酸酐为醋化剂进行复合变性,制备机械活化玉米交联酯化复合变性淀粉,考察反应温度、交联剂用量、交联pH值、交联时间、酯化剂用量、酯化pH值、酯化时间等因素对交联酯化淀粉糊冷黏度的影响,与原玉米淀粉合成的交联酯化淀粉进行比较,研究了产物的理化特性,并利用红外光谱、X射线衍射对产物的结构进行表征分析。结果表明:各因素对机械活化玉米淀粉的交联酯化反应均有影响。对于机械活化1.0 h的玉米淀粉,在反应温度40℃、三偏磷酸钠1.0%、交联pH值10.0、交联时间2.0 h、醋酸酐用量0.5 mL、酯化pH值9.0、酯化时间60 min的条件下,所制备的机械活化玉米交联酯化淀粉糊的冷黏度由活化淀粉的466 mPa.s提高到1 629 mPa.s,淀粉糊液黏度的稳定性、抗酸性、抗老化性明显提高。红外光谱和X射线衍射图谱显示,淀粉经过交联酯化复合变性处理后,分子结构上引入新的化学基团,交联酯化淀粉属于V型结晶。%Cross-linking and esterifying starch of mechanical activated maize starch was prepared by mechanical activated maize starch as raw material,and sodium trimetaphosophate as cross-linking agent and acetic anhydride in acetification.The effects of reaction temperature,cross-linking agent and esterifying agent dosage,pH value and cross-linking time on the cold viscosity of cross-linking and esterifying starch paste were investigated.The physical and chemical parameters of the cross-linking and esterifying starch of mechanical activated maize starch and cross-linking and esterifying starch of raw maize starch were studied.The structure of cross-linking and esterifying of mechanical activated maize starch were characterized by using Fourier transform infrared spectrogram(FTIR) and X-ray diffraction(XRD).The results indicated that the reaction conditions affected the

  6. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    OpenAIRE

    2007-01-01

    Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a...

  7. Effects of Different Comsteep Liquids on Structure of Starch and Protein Binding in Corn Endosperm

    Directory of Open Access Journals (Sweden)

    Rong Yan

    2015-07-01

    Full Text Available The changes in the structures of corn endosperms immersed in different reagents were studied, in order to preliminarily determine the mode of binding of starch and protein in the endosperm. The corn endosperm was immersed in Sulfurous acid, NaOH, ethanol, L-cysteine and morel berry, respectively. The dissociated starch content was analyzed using water as the reference. The results of the treatment were analyzed by the dissociated starch content, optical microscopy and scanning electron microscopy. The test results showed that by immersing in NaOH solution, the protein matrix was effectively decomposed, the protein in the endosperm was dissolved and the highest amount of starch granules were released. Sulfurous acid and L-cysteine solution could make the protein matrix into pieces by destroying intermolecular disulfide bridge and the starch granules would be released. There were some holes on the surface of starch granules after L-cysteine steeping. Immersed in the morel berry, there were holes on the protein matrix surface and the water absorption of corn endosperm was improved. In case of the sample immersed in ethanol, the zein was dissolved, whereas the matrix protein was still intact with the starch grains that still bound to it. By analysis of the microscopic structure and morphological change of starch and protein in corn endospers in different comsteep liquor, it is demonstrated that the main reason which the starch grains were tightly wrapped by Glutenin is the intermolecular disulfide bonds in glutelin. In addition, a part of the protein combined with starch granules directly. The study provided a reference for exploring the structure of binding of starch and protein and their interaction in corn.

  8. Gibberellins regulate seed germination in tomato by endosperm weakening: a study with gibberellin-deficient mutants.

    Science.gov (United States)

    Groot, S P; Karssen, C M

    1987-08-01

    The germination of seeds of tomato [Lycopersicon esculentum (L.) Mill.] cv. Moneymaker has been compared with that of seeds of the gibberellin-deficient dwarf-mutant line ga-1, induced in the same genetic background. Germination of tomato seeds was absolutely dependent on the presence of either endogenous or exogenous gibberellins (GAs). Gibberellin A4+7 was 1000-fold more active than commercial gibberellic acid in inducing germination of the ga-1 seeds. Red light, a preincubation at 2°C, and ethylene did not stimulate germination of ga-1 seeds in the absence of GA4+7; however, fusicoccin did stimulate germination independently. Removal of the endosperm and testa layers opposite the radicle tip caused germination of ga-1 seeds in water. The seedlings and plants that develop from the detipped ga-1 seeds exhibited the extreme dwarfy phenotype that is normal to this genotype. Measurements of the mechanical resistance of the surrounding layers showed that the major action of GAs was directed to the weakening of the endosperm cells around the radicle tip. In wild-type seeds this weakening occurred in water before radicle protrusion. In ga-1 seeds a similar event was dependent on GA4+7, while fusicoccin also had some activity. Simultaneous incubation of de-embryonated endosperms and isolated axes showed that wild-type embryos contain and endosperm-weakening factor that is absent in ga-1 axes and is probably a GA. Thus, an endogenous GA facilitates germination in tomato seeds by weakening the mechanical restraint of the endosperm cells to permit radicle protrusion.

  9. Maize Arabinoxylan Gels as Protein Delivery Matrices

    Directory of Open Access Journals (Sweden)

    Ana Luisa Martínez-López

    2009-04-01

    Full Text Available The laccase induced gelation of maize bran arabinoxylans at 2.5% (w/v in the presence of insulin or β-lactoglobulin at 0.1% (w/v was investigated. Insulin and β-lacto-globulin did not modify either the gel elasticity (9 Pa or the cross-links content (0.03 and 0.015 mg di- and triferulic acids/mg arabinoxylan, respectively. The protein release capability of the gel was also investigated. The rate of protein release from gels was dependent on the protein molecular weight. The apparent diffusion coefficient was 0.99 × 10-7 and 0.79 × 10-7 cm2/s for insulin (5 kDa and β-lactoglobulin (18 kDa, respectively. The results suggest that maize bran arabinoxylan gels can be potential candidates for the controlled release of proteins.

  10. Dosage effect of high-amylose modifier gene(s) on the starch structure of maize amylose-extender mutant.

    Science.gov (United States)

    Jiang, Hongxin; Campbell, Mark; Wu, Yusheng; Du, Shuangkui; Srichuwong, Sathaporn; Jane, Jay-Lin

    2015-01-21

    The objective of this study was to investigate how dosages of high-amylose modifier (HAM) gene(s) affected the structure of maize amylose extender (ae) mutant starch. GEMS-0067 (G), a homozygous mutant of ae and the HAM gene(s), and H99ae (H), an ae single mutant, were self-pollinated or inter-crossed to produce maize endosperms of G/G, G/H, H/G, and H/H with 3, 2, 1, and 0 doses of HAM gene(s), respectively. Endosperm starch was fractionated into amylopectin, amylose, and intermediate component (IC) of large and small molecular weights using 1-butanol precipitation of amylose followed by gel-permeation chromatography. Increases in the dosage of HAM gene(s) from 0 to 3 decreased the amylopectin content. The HAM-gene dosage significantly changed the branch chain-length of small-molecular-weight IC, but had little effect on the branch chain-length distributions of amylopectin and large-molecular-weight IC and the molecular structure of amylose.

  11. QTLs and candidate genes for desiccation and abscisic acid content in maize kernels

    Directory of Open Access Journals (Sweden)

    Charcosset Alain

    2010-01-01

    Full Text Available Abstract Background Kernel moisture at harvest is an important trait since a low value is required to prevent unexpected early germination and ensure seed preservation. It is also well known that early germination occurs in viviparous mutants, which are impaired in abscisic acid (ABA biosynthesis. To provide some insight into the genetic determinism of kernel desiccation in maize, quantitative trait loci (QTLs were detected for traits related to kernel moisture and ABA content in both embryo and endosperm during kernel desiccation. In parallel, the expression and mapping of genes involved in kernel desiccation and ABA biosynthesis, were examined to detect candidate genes. Results The use of an intermated recombinant inbred line population allowed for precise QTL mapping. For 29 traits examined in an unreplicated time course trial of days after pollination, a total of 78 QTLs were detected, 43 being related to kernel desiccation, 15 to kernel weight and 20 to ABA content. Multi QTL models explained 35 to 50% of the phenotypic variation for traits related to water status, indicating a large genetic control amenable to breeding. Ten of the 20 loci controlling ABA content colocated with previously detected QTLs controlling water status and ABA content in water stressed leaves. Mapping of candidate genes associated with kernel desiccation and ABA biosynthesis revealed several colocations between genes with putative functions and QTLs. Parallel investigation via RT-PCR experiments showed that the expression patterns of the ABA-responsive Rab17 and Rab28 genes as well as the late embryogenesis abundant Emb5 and aquaporin genes were related to desiccation rate and parental allele effect. Database searches led to the identification and mapping of two zeaxanthin epoxidase (ZEP and five novel 9-cis-epoxycarotenoid dioxygenase (NCED related genes, both gene families being involved in ABA biosynthesis. The expression of these genes appeared independent in

  12. Global Identification of Significantly Expressed Genes in Developing Endosperm of Rice by Expression Sequence Tags and cDNA Array Approaches

    Institute of Scientific and Technical Information of China (English)

    Qichao Tu; Haitao Dong; Haigen Yao; Yongqi Fang; Cheng'en Dai; Hongmei Luo; Jian Yao; Dong Zhao; Debao Li

    2008-01-01

    Rice endosperm plays a very important role in seedling germination and determines the qualities of fice grain.Although studies on specific gene categories in endosperm have been carried out,global view of gene expression at a transcription level in rice endosperm is still limited.To gain a better understanding of the global and tissue-specific gene expression profiles in rice endosperm,a cDNA library from rice endosperm of immature seeds was sequenced.A cDNA array was constructed based on the tentative unique transcripts derived from expression sequence tag (EST) assembling results and then hybridized with cONAs from five different tissues or organs including endosperm,embryo,leaf,stem and root of rice.Significant redundancy was found for genes encoding prolamin,glutelin,allergen,and starch synthesis proteins,accounting for~34% of the total ESTs obtained.The cDNA array revealed 87 significantly expressed genes in endosperm compared with the other four organs or tissues.These genes included 13 prolamin family proteins,17 glutelin family proteins,12 binding proteins,nine catalytic proteins and four ribosomal proteins,indicating a complicated biological processing in rice endosperm.In addition,Northern verification of 1,4-alpha-glucan branching enzyme detected two isoforms in rice endosperm,the larger one of which only existed in endosperm.

  13. CHANGES IN ENDOGENOUS GENE TRANSCRIPT AND PROTEIN LEVELS IN MAIZE PLANTS EXPRESSING THE SOYBEAN FERRITIN TRANSGENE

    Directory of Open Access Journals (Sweden)

    Milly N Kanobe

    2013-06-01

    Full Text Available Transgenic agricultural crops with increased nutritive value present prospects for contributing to public health. However, their acceptance is poor in many countries due to the perception that genetic modification may cause unintended effects on expression of native genes in the host plant. Here, we tested effects of soybean ferritin transgene (SoyFer1, M64337 on transcript and protein levels of endogenous genes in maize. Results showed that the transgene was successfully introduced and expressed in the maize seed endosperm. mRNA abundance of seven tested iron homeostasis genes and seed storage protein genes differed significantly between seed samples positive and negative for the transgene. The PCR negative samples had higher zein and total protein content compared to the positive samples. However, PCR positive samples had significantly higher concentrations of calcium, magnesium and iron. We have shown that the soybean ferritin transgene affected the expression of native iron homeostasis genes in the maize plant. These results underscore the importance of taking a holistic approach to the evaluation of transgenic events in target plants, comparing the transgenic plant to the untransformed controls.

  14. Nucleotide Diversity of Maize ZmBT1 Gene and Association with Starch Physicochemical Properties

    Science.gov (United States)

    Xu, Shuhui; Yang, Zefeng; Zhang, Enying; Jiang, Ying; Pan, Liang; Chen, Qing; Xie, Zhengwen; Xu, Chenwu

    2014-01-01

    Cereal Brittle1 protein has been demonstrated to be involved in the ADP-Glc transport into endosperm plastids, and plays vital roles in the biosynthesis of starch. In this study, the genomic sequences of the ZmBT1 gene in 80 elite maize inbred lines were obtained, and the nucleotide polymorphisms and haplotype diversity were detected. A total of 30 variants, including 22 SNPs and 8 indels, were detected from the full sequences of this gene. Among these polymorphic sites, 9 SNPs and 2 indels were found to be located in the coding region. The polymorphisms of CDS sequences classified the maize ZmBT1 gene into 6 haplotypes, which encode 6 different ZmBT1 proteins. Neutrality tests revealed a decrease in population size and/or balancing selection on the maize ZmBT1 locus. To detect the association between sequence variations of this gene and the starch physicochemical properties, 7 pasting and 4 gelatinization traits of starch were measured for the tested inbred lines using rapid visco analyzer (RVA) and differential scanning calorimeter (DSC), respectively. The result of association analysis revealed that an indel in the coding region was significantly associated with the phenotypic variation of starch gelatinization enthalpy. PMID:25084007

  15. Nucleotide diversity of Maize ZmBT1 gene and association with starch physicochemical properties.

    Directory of Open Access Journals (Sweden)

    Shuhui Xu

    Full Text Available Cereal Brittle1 protein has been demonstrated to be involved in the ADP-Glc transport into endosperm plastids, and plays vital roles in the biosynthesis of starch. In this study, the genomic sequences of the ZmBT1 gene in 80 elite maize inbred lines were obtained, and the nucleotide polymorphisms and haplotype diversity were detected. A total of 30 variants, including 22 SNPs and 8 indels, were detected from the full sequences of this gene. Among these polymorphic sites, 9 SNPs and 2 indels were found to be located in the coding region. The polymorphisms of CDS sequences classified the maize ZmBT1 gene into 6 haplotypes, which encode 6 different ZmBT1 proteins. Neutrality tests revealed a decrease in population size and/or balancing selection on the maize ZmBT1 locus. To detect the association between sequence variations of this gene and the starch physicochemical properties, 7 pasting and 4 gelatinization traits of starch were measured for the tested inbred lines using rapid visco analyzer (RVA and differential scanning calorimeter (DSC, respectively. The result of association analysis revealed that an indel in the coding region was significantly associated with the phenotypic variation of starch gelatinization enthalpy.

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

    Science.gov (United States)

    Shi, Jinrui; Wang, Hongyu; Schellin, Kathleen; Li, Bailin; Faller, Marianna; Stoop, Johan M; Meeley, Robert B; Ertl, David S; Ranch, Jerry P; Glassman, Kimberly

    2007-08-01

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

  17. Proteomic and genetic analysis of wheat endosperm albumins and globulins using deletion lines of cultivar Chinese Spring

    DEFF Research Database (Denmark)

    Merlino, Marielle; Bousbata, Sabrina; Svensson, Birte;

    2012-01-01

    Albumins and globulins from the endosperm of Triticum aestivum L. cv Chinese Spring (CS) were analysed to establish a proteome reference map for this standard wheat cultivar. Approximately, 1,145 Coomassie-stained spots were detected by two-dimensional gel electrophoresis (2DE), 410 of which were...... the composition and genetics of a complex tissue, such as the wheat endosperm.......Albumins and globulins from the endosperm of Triticum aestivum L. cv Chinese Spring (CS) were analysed to establish a proteome reference map for this standard wheat cultivar. Approximately, 1,145 Coomassie-stained spots were detected by two-dimensional gel electrophoresis (2DE), 410 of which were...... in endosperm proteins due to chromosomal deletions. This differential analysis of spots allowed structural or regulatory genes, encoding 211 proteins, to be located on segments of the 21 wheat chromosomes. In addition, variance analysis of quantitative variations in spot volume showed that the expression...

  18. Protein bodies of castor bean endosperm: isolation, fractionation, and the characterization of protein components.

    Science.gov (United States)

    Tully, R E; Beevers, H

    1976-12-01

    Protein bodies in the endosperm of castor bean seeds (Ricinus communis L.) contain phytin globoids and protein crystalloids embedded in an amorphous proteinaceous matrix. The protein bodies are apparently surrounded by a single membrane. The protein bodies were isolated by grinding and centrifuging in glycerol. Such isolated protein bodies were almost identical (after cytological fixation) to those observed in situ, except that the globoids were lost. However, membrane-like structures appear to have surrounded the globoids. Histochemical analysis of the isolated protein bodies showed that carbohydrates (glycoproteins) are localized only in the matrix region.Addition of water to protein bodies in glycerol caused dissolution of the matrix, and release of the globoids and crystalloids. When the crystalloids were centrifuged on sucrose density gradients, they were recovered at an equilibrium density of 1.29 to 1.30 g/ml. The crystalloids were only slightly soluble in most aqueous buffers but were very soluble in sodium dodecyl sulfate, urea, or NaOH solutions.Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and chromatography on ion exchange celluloses show that the protein bodies are composed of one major and several minor anodic proteins. The major protein, along with a few of the minor proteins, is localized in the crystalloids.The major protein (molecular weight 65,000) was converted by mercaptoethanol into subunits with molecular weights of 32,000 and 15,800. It is proposed that the protein is made up of two of the smaller subunits and one of the larger, linked by disulfide bridges. None of the crystalloid proteins appear to be glycosylated.The water-soluble matrix fraction is composed mainly of two proteins, with molecular weights of 12,500 and 10,300 on the gels. Neither is a glycoprotein, and neither can be reduced with mercaptoethanol to give subunits. The soluble fraction also contains other lesser components among which are

  19. Biotechnology in maize breeding

    Directory of Open Access Journals (Sweden)

    Mladenović-Drinić Snežana

    2004-01-01

    Full Text Available Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

  20. Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm

    Energy Technology Data Exchange (ETDEWEB)

    Harholt, Jesper; Bach, Inga C; Lind-Bouquin, Solveig; Nunan, Kylie J.; Madrid, Susan M.; Brinch-Pedersen, Henrik; Holm, Preben B.; Scheller, Henrik V.

    2009-12-08

    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 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 three fold relative to wild type. The grains were shriveled 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 kD and 85 kD. Ferulic acid esterase expressing grains were also shriveled 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.

  1. Generation of transgenic wheat (Triticum aestivum L.) accumulating heterologous endo-xylanase or ferulic acid esterase in the endosperm.

    Science.gov (United States)

    Harholt, Jesper; Bach, Inga C; Lind-Bouquin, Solveig; Nunan, Kylie J; Madrid, Susan M; Brinch-Pedersen, Henrik; Holm, Preben B; Scheller, Henrik V

    2010-04-01

    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.

  2. Diverged Copies of the Seed Regulatory Opaque-2 Gene by a Segmental Duplication in the Progenitor Genome of Rice,Sorghum,and Maize

    Institute of Scientific and Technical Information of China (English)

    Jian-Hong Xu; Joachim Messing

    2008-01-01

    Comparative analyses of the sequence of entire genomes have shown that gene duplications,chromosomal segmental duplications.or even whole genome duplications(WGD)have played prominent roles in the evolution of many eukaryotic species.Here,we used the ancient duplication of a well known transcription factor in maize,encoded by the Opaque-2(02)IOCUS,to examine the generaI features of divergences of chromosomaI segmentaI duplications in a lineagespecific manner.We took advantage of contiguous chromosomal sequence information in rice(Oryza sativa,Nipponbare).sorghum(Sorghum bicoloc Btx623),and maize(Zea mays,B73)that were aligned by conserved gene order(synteny).This analysis showed that the maize O2 locus is contained within a 1.25 million base-pair(Mb)segment on chromosome 7.which was duplicated≈56 million years ago(mya)before the split of rice and maize 50 mya.The duplicated region on chromosome 1 is only half the size and contains the maize OHP gene.which does not restore the o2 mutation although it encodes a protein with the same DNA and protein binding properties in endosperm.The segmental duplication iS not only found in rice,but also in sorghum,which split from maize 11.9 mya.A detailed analysis of the duplicated regions provided examples for complex rearrangements including deletions.duplications,conversions,inversions,and translocations.Furthermore,the rice and sorghum genomes appeared to be more stable than the maize genome,probably because maize underwent allotetraploidization and then diploidization.

  3. Mobilization of lipid reserves during germination of oat (Avena sativa L.), a cereal rich in endosperm oil.

    Science.gov (United States)

    Leonova, Svetlana; Grimberg, Asa; Marttila, Salla; Stymne, Sten; Carlsson, Anders S

    2010-06-01

    Since the cereal endosperm is a dead tissue in the mature grain, beta-oxidation is not possible there. This raises the question about the use of the endosperm oil in cereal grains during germination. In this study, mobilization of lipids in different tissues of germinating oat grains was analysed using thin-layer and gas chromatography. The data imply that the oat endosperm oil [triacylglycerol (TAG)] is not a dead-end product as it was absorbed by the scutellum, either as free fatty acids (FFAs) released from TAG or as intact TAG immediately degraded to FFAs. These data were supported by light and transmission electron microscopy (LM and TEM) studies where close contact between endosperm lipid droplets and the scutellum was observed. The appearance of the fused oil in the oat endosperm changed into oil droplets during germination in areas close to the aleurone and the scutellar epithelium. However, according to the data obtained by TEM these oil droplets are unlikely to be oil bodies surrounded by oleosins. Accumulation of FFA pools in the embryo suggested further transport of FFAs from the scutellum. Noticeably high levels of TAG were also accumulated in the embryo but were not synthesized by re-esterification from imported FFAs. Comparison between two oat cultivars with different amounts of oil and starch in the endosperm suggests that an increased oil to starch ratio in oat grains does not significantly impact the germination process.

  4. Ethylene produced by the endosperm is involved in the regulation of nucellus programmed cell death in Sechium edule Sw.

    Science.gov (United States)

    Lombardi, Lara; Mariotti, Lorenzo; Picciarelli, Piero; Ceccarelli, Nello; Lorenzi, Roberto

    2012-05-01

    The nucellus is a maternal tissue that feeds the developing embryo and the secondary endosperm. During seed development the cells of the nucellus suffer a degenerative process early after fertilization as the cellular endosperm expands and accumulates reserves. Nucellar cell degeneration has been characterized as a form of developmentally programmed cell death (PCD). In this work we analysed the role of the endosperm as main regulator of nucellus PCD. We demonstrated that endosperm produces high amount of ethylene, nitric oxide and indoleacetic acid. We examined the role of these small and diffusible signalling molecules in the regulation of nucellus PCD and we tried to elucidate how they can cooperate and regulate each other into the endosperm. We showed that ethylene acts a positive regulator of nucellus PCD and its synthesis can be in part induced by nitric oxide. High levels of IAA were detected both in the endosperm and in dying nucellus but this hormone is not directly involved in the execution of PCD. © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Application of Rapid Visco Analyser (RVA) viscograms and chemometrics for maize hardness characterisation.

    Science.gov (United States)

    Guelpa, Anina; Bevilacqua, Marta; Marini, Federico; O'Kennedy, Kim; Geladi, Paul; Manley, Marena

    2015-04-15

    It has been established in this study that the Rapid Visco Analyser (RVA) can describe maize hardness, irrespective of the RVA profile, when used in association with appropriate multivariate data analysis techniques. Therefore, the RVA can complement or replace current and/or conventional methods as a hardness descriptor. Hardness modelling based on RVA viscograms was carried out using seven conventional hardness methods (hectoliter mass (HLM), hundred kernel mass (HKM), particle size index (PSI), percentage vitreous endosperm (%VE), protein content, percentage chop (%chop) and near infrared (NIR) spectroscopy) as references and three different RVA profiles (hard, soft and standard) as predictors. An approach using locally weighted partial least squares (LW-PLS) was followed to build the regression models. The resulted prediction errors (root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP)) for the quantification of hardness values were always lower or in the same order of the laboratory error of the reference method.

  6. Highly branched dextrin prepared from high-amylose maize starch using waxy rice branching enzyme (WRBE).

    Science.gov (United States)

    Tian, Yaoqi; Chen, Huangli; Zhang, Xiwen; Zhan, Jinling; Jin, Zhengyu; Wang, Jinpeng

    2016-07-15

    Branching enzyme (BE, EC 2.4.1.18) was isolated from the developing waxy rice endosperm and used to prepare a highly branched dextrin based on high-amylose maize starch (HAMS) as a substrate. The molecular mass of the starch initially degraded quickly from 2.5 × 10(7) to 4.1 × 10(5)Da, and then stabilized, with a minimal increase during the BE treatment. The resultant branched dextrin had a narrow size distribution, with a mean molecular weight of 5.1 × 10(5)Da and a polydispersity index (PI) of 1.567. The results of high-performance anion exchange chromatography indicated that the degree of polymerization (DP) of the branched chains ranged from 3 to 27; approximately 75.26% of these chains were short (DPhighly branched dextrins with a narrow size distribution and short side chains. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Ethanol Fermentation Performance of Grain Sorghums (Sorghum bicolor) with Modified Endosperm Matrices

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X.; Jampala, B; Robbins, A; Hays, D; Yan, S; Xu, F; Rooney, W; Peterson, G; Shi, Y; Wang, D

    2010-01-01

    We tested 13 sorghum entries (lines and hybrids) with different endosperm matrices for ethanol production using a laboratory dry grind process. Waxy and heterowaxy samples had the highest efficiencies. Free amino nitrogen (FAN) contents in sorghum samples were positively related to the fermentation rate during fermentation (R{sup 2} = 0.8618). Dried distiller's grain with solubles (DDGS) from different sorghums had significantly different crude protein and crude fat contents. Residual starch content in DDGS ranged from 0.60% for the most efficient sample to 2.66% for the least efficient sample. This study showed that the HD lines (TX1, TX3, TX5, TX7, and TX9) with modified endosperm protein matrix have several attributes desirable for ethanol production: easily pasted starch granules, significantly higher FAN content in finished mashes, 30-45% faster ethanol fermentation rate during early stages, and 50-60% higher lysine content in DDGS.

  8. Functional and structural characterization of plastidic starch phosphorylase during barley endosperm development.

    Science.gov (United States)

    Cuesta-Seijo, Jose A; Ruzanski, Christian; Krucewicz, Katarzyna; Meier, Sebastian; Hägglund, Per; Svensson, Birte; Palcic, Monica M

    2017-01-01

    The production of starch is essential for human nutrition and represents a major metabolic flux in the biosphere. The biosynthesis of starch in storage organs like barley endosperm operates via two main pathways using different substrates: starch synthases use ADP-glucose to produce amylose and amylopectin, the two major components of starch, whereas starch phosphorylase (Pho1) uses glucose-1-phosphate (G1P), a precursor for ADP-glucose production, to produce α-1,4 glucans. The significance of the Pho1 pathway in starch biosynthesis has remained unclear. To elucidate the importance of barley Pho1 (HvPho1) for starch biosynthesis in barley endosperm, we analyzed HvPho1 protein production and enzyme activity levels throughout barley endosperm development and characterized structure-function relationships of HvPho1. The molecular mechanisms underlying the initiation of starch granule biosynthesis, that is, the enzymes and substrates involved in the initial transition from simple sugars to polysaccharides, remain unclear. We found that HvPho1 is present as an active protein at the onset of barley endosperm development. Notably, purified recombinant protein can catalyze the de novo production of α-1,4-glucans using HvPho1 from G1P as the sole substrate. The structural properties of HvPho1 provide insights into the low affinity of HvPho1 for large polysaccharides like starch or amylopectin. Our results suggest that HvPho1 may play a role during the initiation of starch biosynthesis in barley.

  9. Transgenic multivitamin corn through biofortification of endosperm with three vitamins representing three distinct metabolic pathways

    OpenAIRE

    2009-01-01

    Vitamin deficiency affects up to 50% of the world's population, disproportionately impacting on developing countries where populations endure monotonous, cereal-rich diets. Transgenic plants offer an effective way to increase the vitamin content of staple crops, but thus far it has only been possible to enhance individual vitamins. We created elite inbred South African transgenic corn plants in which the levels of 3 vitamins were increased specifically in the endosperm through the simultaneou...

  10. Entwicklung transgener Gerste (Hordeum vulgare L.) mit dem Ziel der Lysin- und Threoninanreicherung im Endosperm

    OpenAIRE

    Ibrahim, Ahmed Shawky Ahmed

    2006-01-01

    An efficient Agrobacterium-mediated barley transformation system was established with a transformation rate of 13.4 % on average. Towards improving the nutritional value of barley, a set of novel transformation vectors was developed including the dapA and lysC genes encoding the feed-back-inhibition insensitive form of the dihydrodipicolinate synthase (DHDPS) and aspartate kinase (AK) respectively. Both genes under the control of the endosperm-specific D-hordein promoter or the constitutive u...

  11. Nitrogen and phosphorus compounds in the aleurone grains of Iris pseudoacorus endosperm and Pisum sativum cotyledons

    OpenAIRE

    Ligia Konopska

    2015-01-01

    Aleurone grains from Iris pseudoacorus endosperm and Pisum sativum cotyledons were isolated partly according to Tombs's method (1967). Nitrogen compounds content was determined in them by Kjeldahl's micromethod, and in the particular fractions after Thiman and Laloraya (1960). Mainly protein N was detected in the aleurone grains, constituting 14.8 and 15.2 per cent of the dry mass of pea and Iris seeds, respectively. Moreover, phosphorus compounds were fractionated according to Holden and Pir...

  12. The Bsister MADS gene FST determines ovule patterning and development of the zygotic embryo and endosperm.

    Directory of Open Access Journals (Sweden)

    Dong Sun Lee

    Full Text Available Many homeotic MADS-box genes have been identified as controllers of the floral transition and floral development. However, information regarding Bsister (Bs-function genes in monocots is still limited. Here, we describe the functional characterization of a Bs-group MADS-box gene FEMALE-STERILE (FST, whose frame-shift mutation (fst results in abnormal ovules and the complete abortion of zygotic embryos and endosperms in rice. Anatomical analysis showed that the defective development in the fst mutant exclusively occurred in sporophytic tissues including integuments, fertilized proembryos and endosperms. Analyses of the spatio-temporal expression pattern revealed that the prominent FST gene products accumulated in the inner integument, nucellar cell of the micropylar side, apical and base of the proembryos and free endosperm nuclei. Microarray and gene ontology analysis unraveled substantial changes in the expression level of many genes in the fst mutant ovules and seeds, with a subset of genes involved in several developmental and hormonal pathways appearing to be down-regulated. Using both forward and reverse genetics approaches, we demonstrated that rice FST plays indispensable roles and multiple functions during ovule and early seed development. These findings support a novel function for the Bs-group MADS-box genes in plants.

  13. Evaluation and characterization of an endosperm-specific sbeⅡa promoter in wheat

    Institute of Scientific and Technical Information of China (English)

    MIAO Hongmei; Fleming Joy E.; L(U) Debing; HAN Jinfeng

    2004-01-01

    Starch, the main component of the wheat grain,is the product of a complex biochemical pathway. The sbeⅡa gene plays a key role in controlling the synthesis of starch, in particular, the biosynthesis of amylopectin, in maturing wheat grain. To investigate its regulatory mechanisms and endosperm-specific expression pattern, the sbeⅡa promoter (3094 bp in length) was cloned using APCR and sequenced.The effect of a series of deletions was studied using a GUS transient assay system. Results showed that the 3094 bp sequence (sbe.g construct) exhibited full stable promoting activity and that the activities of 5′ or 3′ deletions reduced levels of GUS expression. Some constructs with internal deletions showed only weak activity, however, sbe.e, with a deletion from -1579-1210 bp resulted in higher levels of expression than the full-length promoter sequence, sbe.g. This indicates that motifs such as the -300 bp element, G-box and/or P-box act as positive elements and are necessary in determining the promoter's endosperm-specific pattern and that negative repressor elements or motifs may also be present within the -1579-1210 bp sequence. The age of wheat endosperm tissue used in the GUS-transient assay system is shown to be of significant importance.

  14. The Maize megagametophyte

    OpenAIRE

    Evans, M M S; U. Grossniklaus

    2008-01-01

    The life cycle of plants alternates between a diploid and a haploid generation. In flowering plants the haploid gametophytes are sexually dimorphic and produce the gametes, which fuse to produce the diploid sporophyte of the next generation. The megagametophyte of maize follows the Polygonum-type pattern of development:one of the four meiotic products, the functional megaspore, undergoes three free nuclear divisions to produce a polarized, eight-nucleate syncytium. Cellularization produces se...

  15. Maize variety and method of production

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Markus; Hake, Sarah; Kraemer, Florian J

    2014-05-27

    The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

  16. Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases

    Directory of Open Access Journals (Sweden)

    Rosa A. Malvar

    2010-02-01

    Full Text Available Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize’s defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs.

  17. MaizeGDB: The Maize Genetics and Genomics Database.

    Science.gov (United States)

    Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

    2016-01-01

    MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

  18. Small kernel 1 encodes a pentatricopeptide repeat protein required for mitochondrial nad7 transcript editing and seed development in maize (Zea mays) and rice (Oryza sativa).

    Science.gov (United States)

    Li, Xiao-Jie; Zhang, Ya-Feng; Hou, Mingming; Sun, Feng; Shen, Yun; Xiu, Zhi-Hui; Wang, Xiaomin; Chen, Zong-Liang; Sun, Samuel S M; Small, Ian; Tan, Bao-Cai

    2014-09-01

    RNA editing modifies cytidines (C) to uridines (U) at specific sites in the transcripts of mitochondria and plastids, altering the amino acid specified by the DNA sequence. Here we report the identification of a critical editing factor of mitochondrial nad7 transcript via molecular characterization of a small kernel 1 (smk1) mutant in Zea mays (maize). Mutations in Smk1 arrest both the embryo and endosperm development. Cloning of Smk1 indicates that it encodes an E-subclass pentatricopeptide repeat (PPR) protein that is targeted to mitochondria. Loss of SMK1 function abolishes the C → U editing at the nad7-836 site, leading to the retention of a proline codon that is edited to encode leucine in the wild type. The smk1 mutant showed dramatically reduced complex-I assembly and NADH dehydrogenase activity, and abnormal biogenesis of the mitochondria. Analysis of the ortholog in Oryza sativa (rice) reveals that rice SMK1 has a conserved function in C → U editing of the mitochondrial nad7-836 site. T-DNA knock-out mutants showed abnormal embryo and endosperm development, resulting in embryo or seedling lethality. The leucine at NAD7-279 is highly conserved from bacteria to flowering plants, and analysis of genome sequences from many plants revealed a molecular coevolution between the requirement for C → U editing at this site and the existence of an SMK1 homolog. These results demonstrate that Smk1 encodes a PPR-E protein that is required for nad7-836 editing, and this editing is critical to NAD7 function in complex-I assembly in mitochondria, and hence to embryo and endosperm development in maize and rice.

  19. Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

    Science.gov (United States)

    Midorikawa, Keiko; Kuroda, Masaharu; Terauchi, Kaede; Hoshi, Masako; Ikenaga, Sachiko; Ishimaru, Yoshiro; Abe, Keiko; Asakura, Tomiko

    2014-01-01

    The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

  20. Nitrate leaching from Silage Maize

    OpenAIRE

    Hansen, Elly Møller; Eriksen, Jørgen

    2009-01-01

    During the last 20 years the area with maize in Denmark has increased dramatically and reached 163,000 ha in 2008. Silage maize is easy to grow, is a suitable fodder for cows and goes well with grass-clover in the diet. This means that silage maize is often found in crop rotations with grass-clover on sandy soils in western Denmark. The ploughing in of grass-clover fields poses a serious risk of increased nitrate leaching on a coarse sandy soil, even when carried out in spring. With increased...

  1. Resistance of maize varieties to the maize weevil Sitophilus zeamais

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... as an increasingly important problem in Africa (Markham et al., 1994). Cheap and ... Removal of parent weevils and placement on a fresh seed medium ..... stored maize. An M.Sc. Thesis presented to the School of Graduate.

  2. In vitro biochemical characterization of all barley endosperm starch synthases

    DEFF Research Database (Denmark)

    Cuesta-Seijo, Jose A.; Nielsen, Morten M.; Ruzanski, Christian

    2016-01-01

    Starch is the main storage polysaccharide in cereals and the major source of calories in the human diet. It is synthesized by a panel of enzymes including five classes of starch synthases (SSs). While the overall starch synthase (SS) reaction is known, the functional differences between the five SS....... Here we provide a detailed biochemical study of the activity of all five classes of SSs in barley endosperm. Each enzyme was produced recombinantly in E. coli and the properties and modes of action in vitro were studied in isolation from other SSs and other substrate modifying activities. Our results...

  3. Structure and Composition of Protein Bodies from Wild-Type and High-Lysine Barley Endosperm

    DEFF Research Database (Denmark)

    Ingversen, J.

    1975-01-01

    Protein bodies were isolated from 13 and 28 day old endosperms of barley mutant 1508 and its wild type, Bomi barley. The fine structure of the isolated protein bodies was determined by electron microscopy, and the proteins present in the preparations characterized by amino-acid analysis and SDS...... with a granular component. Particles with the same structure were present in the protein body preparation from the mutant, where, however, the granular component was the most prominent. Amino-acid composition and SDS-polyacrylamide gel electrophoresis of the proteins from the protein body preparation revealed...

  4. Distribution of carotenoids in endosperm, germ, and aleurone fractions of cereal grain kernels.

    Science.gov (United States)

    Ndolo, Victoria U; Beta, Trust

    2013-08-15

    To compare the distribution of carotenoids across the grain, non-corn and corn cereals were hand dissected into endosperm, germ and aleurone fractions. Total carotenoid content (TCC) and carotenoid composition were analysed using spectrophotometry and HPLC. Cereal carotenoid composition was similar; however, concentrations varied significantly (paleurone layer had zeaxanthin levels 2- to 5-fold higher than lutein among the cereals. Positive significant correlations (paleurone layer. Our findings suggest that the aleurone of wheat, oat, corn and germ of barley have significantly enhanced carotenoid levels.

  5. Nitrogen and phosphorus compounds in the aleurone grains of Iris pseudoacorus endosperm and Pisum sativum cotyledons

    Directory of Open Access Journals (Sweden)

    Ligia Konopska

    2015-05-01

    Full Text Available Aleurone grains from Iris pseudoacorus endosperm and Pisum sativum cotyledons were isolated partly according to Tombs's method (1967. Nitrogen compounds content was determined in them by Kjeldahl's micromethod, and in the particular fractions after Thiman and Laloraya (1960. Mainly protein N was detected in the aleurone grains, constituting 14.8 and 15.2 per cent of the dry mass of pea and Iris seeds, respectively. Moreover, phosphorus compounds were fractionated according to Holden and Pirie (1955. Analyses demonstrated the presence in aleurone grains of inorganic P, acid-soluble organophosphorus compounds, phospholipids and RNA.

  6. Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

    Directory of Open Access Journals (Sweden)

    Pajić Zorica

    2007-01-01

    Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

  7. Correlation between a loss of auxin signaling and a loss of proliferation in maize antipodal cells

    Science.gov (United States)

    Chettoor, Antony M.; Evans, Matthew M. S.

    2015-01-01

    The plant life cycle alternates between two genetically active generations: the diploid sporophyte and the haploid gametophyte. In angiosperms the gametophytes are sexually dimorphic and consist of only a few cells. The female gametophyte, or embryo sac, is comprised of four cell types: two synergids, an egg cell, a central cell, and a variable number of antipodal cells. In some species the antipodal cells are indistinct and fail to proliferate, so many aspects of antipodal cell function and development have been unclear. In maize and many other grasses, the antipodal cells proliferate to produce a highly distinct cluster at the chalazal end of the embryo sac that persists at the apex of the endosperm after fertilization. The antipodal cells are a site of auxin accumulation in the maize embryo sac. Analysis of different families of genes involved in auxin biosynthesis, distribution, and signaling for expression in the embryo sac demonstrates that all steps are expressed within the embryo sac. In contrast to auxin signaling, cytokinin signaling is absent in the embryo sac and instead occurs adjacent to but outside of the antipodal cells. Mutant analysis shows a correlation between a loss of auxin signaling and a loss of proliferation of the antipodal cells. The leaf polarity mutant Laxmidrib1 causes a lack of antipodal cell proliferation coupled with a loss of DR5 and PIN1a expression in the antipodal cells. PMID:25859254

  8. Cloning and Functional Characterization of the Maize (Zea mays L. Carotenoid Epsilon Hydroxylase Gene.

    Directory of Open Access Journals (Sweden)

    Shu Chang

    Full Text Available The assignment of functions to genes in the carotenoid biosynthesis pathway is necessary to understand how the pathway is regulated and to obtain the basic information required for metabolic engineering. Few carotenoid ε-hydroxylases have been functionally characterized in plants although this would provide insight into the hydroxylation steps in the pathway. We therefore isolated mRNA from the endosperm of maize (Zea mays L., inbred line B73 and cloned a full-length cDNA encoding CYP97C19, a putative heme-containing carotenoid ε hydroxylase and member of the cytochrome P450 family. The corresponding CYP97C19 genomic locus on chromosome 1 was found to comprise a single-copy gene with nine introns. We expressed CYP97C19 cDNA under the control of the constitutive CaMV 35S promoter in the Arabidopsis thaliana lut1 knockout mutant, which lacks a functional CYP97C1 (LUT1 gene. The analysis of carotenoid levels and composition showed that lutein accumulated to high levels in the rosette leaves of the transgenic lines but not in the untransformed lut1 mutants. These results allowed the unambiguous functional annotation of maize CYP97C19 as an enzyme with strong zeinoxanthin ε-ring hydroxylation activity.

  9. Isolation and characterization of esters of indole-3-acetic acid from the liquid endosperm of the horse chestnut (Aesculus species)

    Science.gov (United States)

    Domagalski, W.; Schulze, A.; Bandurski, R. S.

    1987-01-01

    Esters of indole-3-acetic acid were extracted and purified from the liquid endosperm of immature fruits of various species of the horse chestnut (Aesculus parviflora, A. baumanni, A. pavia rubra, and A. pavia humulis). The liquid endosperm contained, at least 12 chromatographically distinct esters. One of these compounds was purified and characterized as an ester of indole-3-acetic acid and myo-inositol. A second compound was found to be an ester of indole-3-acetic acid and the disaccharide rutinose (glucosyl-rhamnose). A third compound was partially characterized as an ester of indole-3-acetic acid and a desoxyaminohexose.

  10. BROWSES ENSILED WITH MAIZE FODDER

    African Journals Online (AJOL)

    Leucaenalmoae., respectively. Gliricidia/maize silages exhibited the best fermentation and nutrient patterns. .... proteolysis or deamination of protein in the silages. The DM losses ..... of legume shrubs and trees as fodders for livestockin the ...

  11. A cor verde do endosperma do café On the green color of coffee endosperm

    Directory of Open Access Journals (Sweden)

    Paulo Mazzafera

    1988-01-01

    Full Text Available Realizaram-se comparações entre as sementes dos cultivares Mundo Novo de Coffea arabica, cujo endosperma é verde, com as do cultivar Cera, dessa espécie, de endosperma amarelo, com o objetivo de determinar os componentes responsáveis por aquela cor. Nas análises de clorofilas, flavonóides, diterpenos totais, ácido clorogênico e íons Mg, Ca, K, Fe e B, nenhuma diferença foi verificada entre os dois cultivares, sugerindo que a coloração verde se deva à presença de outros componentes ou que o 'Cera' apresente um componente que não ocorre no 'Mundo Novo' e que inibe o desenvolvimento da cor verde no seu endosperma.A comparison was made between the green seeded Mundo Novo and the yellow seeded Cera cultivars of Coffea arabica, in order to determine the components responsible for the green color of the endosperm. Both cultivars produce beverage of good quality. Chlorophylls, flavonoids, total diterpens, chlorogenic acid, and K, Ca, Mg, Fe and B ions were determined in beans of both cultivars. No differences between cultivars were found on these component contents, what suggests that the green color may be due to other compounds or that the Cera endosperm may have an inhibitor component of the green color of the coffee beans.

  12. Use of the Endosperm Balance Number (EBN) in Potato Genetics and Breeding

    Institute of Scientific and Technical Information of China (English)

    Carputo Domenico; Jin Liping

    2006-01-01

    Solanum species have a wide geographic distribution and show a large range of ecological adaptation, and thus have developed strong resistances to a wide range of pests, diseases and abiotic stresses. They represent unique material as a source of useful genes and allelic diversity for the tetraploid cultivated potato (Solanum tuberosum). Knowledge of the endosperm balance number (EBN) incompatibility system may be extremely useful for breeders in designing specific crosses schemes for potato breeding. EBN has been experimentally assigned to Solanum species after crosses with standard species whose EBN was arbitrarily established, and assuming the 2: 1 ratio as a prerequisite for normal endosperm development. The role of the EBN incompatibility system in potato breeding is strongly complemented by 2n gametes. Only 2n gametes can allow inter-EBN crosses and thus gene flow between sexually isolated species. This complementary role of EBN and 2n gametes not only facilitates gene introgression between inter-EBN species, but also maintains the ploidy integrity of the two parental species. Examples are given to illustrate how to use EBN in crossing schemes designed for 2x (2EBN) and 2x(1EBN) species. As increasing in the interest in exploiting exotic germplasm for breeding purposes, it is strongly believed that an understanding of EBN can be used for interspecific gene transfer in any crop species where an EBN-like system operates.

  13. Evaluation of Caesalpinia pulcherrima endospermic gum as affinity matrices for galactose-binding lectins interaction

    Directory of Open Access Journals (Sweden)

    Renata Chastinet Braga

    2011-04-01

    Full Text Available Lectins are proteins or glycoproteins able to bind, specifically and reversibly carbohydrates and glycoconjugates. Considering this ability, the utilization of Caesalpinia pulcherrima seeds polysaccharides as an affinity matrix was tested. The endospermic gum were solubilized in distinct concentrations of NaOH and treated with different amounts of epichlorohydrin (ECH forming affinity gels with variable capacity for interaction with galactose- binding lectins. The gel with an ECH/gum ration of 6.0mmol/g was selected as the best affinity matrix. The matrix presented different efficiencies in terms of isolating galactose-binding lectins. C. pulcherrima endospermic galactomannans were purified by ethanol precipitation and the purified galactomannan was crosslinked with the best formulation of gel. The Artocarpus incisa, Ricinus communis and Abrus precatorius lectins showed interactions of 11.5, 17.7 and 47.2mg of retained protein in 1g of gel, respectively; the Artocarpus integrifolia lectin showed the highest affinities (79.7mg/g. The heamaglutination assays confirmed the activity and SDS-PAGE electrophoresis confirmed the isolation of the lectins in a single-step procedure.

  14. In vivo gibberellin biosynthesis in endosperm of Sechium edule Sw. seeds

    Energy Technology Data Exchange (ETDEWEB)

    Ceccarelli, N.; Lorenzi, R. (Universita degli Studi, Pisa (Italy))

    1990-07-01

    Biosynthesis of gibberellins (GAs) was studied in vivo in endosperms of Sechium edule Sw. Exogenous ent-({sup 14}C)kaurene was metabolized into four major products: GA{sub 12}, GA{sub 4}, GA{sub 7} and 16,17-dihydro-16-hydroxy-GA{sub 15} alcohol glucoside. Other minor metabolites were also observed including ent-kaurenol and ent-kaurenal. Conversion of ent-({sup 14}C)kaurene to ent-karuenol glucoside by endosperm cell-free preparations in the presence of UDPG was observed. However, the finding was not confirmed in in vivo studies and is probably artifactual. Overall evidence coming from the analysis of endogenous GAs and in vitro and in vivo biosynthetic studies are discussed in relation to the possible existence in the Sechium seeds of a different route, along with the known pathway, branching from ent-kaurene or ent-7-{alpha}-hydroxykaurenoic acid and this also leading to biologically active GAs.

  15. Metabolic pathways of the wheat (Triticum aestivum endosperm amyloplast revealed by proteomics

    Directory of Open Access Journals (Sweden)

    Dupont Frances M

    2008-04-01

    Full Text Available Abstract Background By definition, amyloplasts are plastids specialized for starch production. However, a proteomic study of amyloplasts isolated from wheat (Triticum aestivum Butte 86 endosperm at 10 days after anthesis (DPA detected enzymes from many other metabolic and biosynthetic pathways. To better understand the role of amyloplasts in food production, the data from that study were evaluated in detail and an amyloplast metabolic map was outlined. Results Analysis of 288 proteins detected in an amyloplast preparation predicted that 178 were amyloplast proteins. Criteria included homology with known plastid proteins, prediction of a plastid transit peptide for the wheat gene product or a close homolog, known plastid location of the pathway, and predicted plastid location for other members of the same pathway. Of these, 135 enzymes were arranged into 18 pathways for carbohydrate, lipid, amino acid, nucleic acid and other biosynthetic processes that are critical for grain-fill. Functions of the other proteins are also discussed. Conclusion The pathways outlined in this paper suggest that amyloplasts play a central role in endosperm metabolism. The interacting effects of genetics and environment on starch and protein production may be mediated in part by regulatory mechanisms within this organelle.

  16. The induction of enzyme activity in the endosperm of germinating castor-bean seeds.

    Science.gov (United States)

    Marriott, K M; Northcote, D H

    1975-10-01

    Endosperm extracts were prepared at various times during germination from intact castor-bean seeds and from seeds from which the embryos had been removed. The sterilized seeds were incubated either on solid water agar or on agar containing 0.3 mM-gibberellic acid. 2. Isocitrate lyase and 3-hydroxyacyl-CoA dehydrogenase had very low activities in the mature seeds, but increased 44-fold and 27-fold respectively during germination. In contrast, the extracts of mature seeds had considerable acid and alkaline lipase activity and this only increased two- to three-fold during the incubation period. 3. Incubation of the seeds with gibberellic acid accelerated the rate of appearance of isocitrate lyase and 3-hydroxyacyl-CoA dehydrogenase. It also increased the total activity attained. However, the application of hormone had, in comparison, little effect on the development of lipase activity. 4. The removal of the embryo had little influence on the development of enzyme activity in the endosperm tissue; only with isocitrate lyase was a decrease in activity observed in the absence of the embryo.

  17. Sequencing the maize genome.

    Science.gov (United States)

    Martienssen, Robert A; Rabinowicz, Pablo D; O'Shaughnessy, Andrew; McCombie, W Richard

    2004-04-01

    Sequencing of complex genomes can be accomplished by enriching shotgun libraries for genes. In maize, gene-enrichment by copy-number normalization (high C(0)t) and methylation filtration (MF) have been used to generate up to two-fold coverage of the gene-space with less than 1 million sequencing reads. Simulations using sequenced bacterial artificial chromosome (BAC) clones predict that 5x coverage of gene-rich regions, accompanied by less than 1x coverage of subclones from BAC contigs, will generate high-quality mapped sequence that meets the needs of geneticists while accommodating unusually high levels of structural polymorphism. By sequencing several inbred strains, we propose a strategy for capturing this polymorphism to investigate hybrid vigor or heterosis.

  18. Increased mortality is predicted of Inachis io larvae caused by Bt-maize pollen in European farmland

    DEFF Research Database (Denmark)

    Holst, Niels; Lang, Andreas; Lövei, Gabor L

    2013-01-01

    be deposited on various plants growing in the landscape, leading to inadvertent ingestion of toxic pollen with plant biomass consumed by these butterfly larvae. To examine the possible effect of this coincidence, we focused our study on the protected butterfly Inachis io and two regions of Europe. Using...... climatic records, maize and butterfly phenology data, we built a simulation model of the butterfly's annual life cycle, overlaid with the phenology of maize pollen deposition on the leaves of the food plant Urtica dioica, and linked these with the dose–response curve of I. io larvae to Bt-maize pollen...... (event MON810). The simulations indicated that in Northern Europe, where I. io is univoltine, Bt-maize pollen would not be present on the food plant at the same time as the I. io larvae. However, in Central and Southern Europe, where I. io is bivoltine, Bt-maize pollen and the second generation I. io...

  19. Influence of maize/lablab intercropping on lepidopterous stem borer infestation in maize.

    Science.gov (United States)

    Maluleke, Mary H; Addo-Bediako, Abraham; Ayisi, Kingsley K

    2005-04-01

    Lepidopterous stem borers seriously affect production of maize, Zea mays L., in sub-Saharan Africa. Intercropping maize with legumes such as lablab, Lablab purpurens (L.), is one of the effective systems to control stem borers. Sole culture maize and maize/lablab intercrop system of different lablab densities were planted at two locations to investigate the effects of intercrop system on incidence and severity of stem borers with particular reference to Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae). Stem borer infestation was found to be more severe in sole culture maize than maize in maize/lablab intercrop. There was a significantly negative relationship between lablab densities and maize grain yields, suggesting a possible competition for resources between the two crops. It was concluded that density of lablab and date of planting of lablab in maize/lablab intercropping have significant affects on stem borer populations and maize grain yields.

  20. IMAZAPYR-RESISTANT MAIZE TECHNOLOGY ADOPTION FOR ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    decisions by protecting maize (Zea mays L.) crop in western Kenya from Striga. Key Words: .... Imazapyr-resistant maize technology adoption for witch weed control. 175. Areas” (IAs) and ..... Iowa State University Press, Ames,. IA, USA. 164p.

  1. Correlation-maximizing surrogate gene space for visual mining of gene expression patterns in developing barley endosperm tissue

    Directory of Open Access Journals (Sweden)

    Usadel Björn

    2007-05-01

    Full Text Available Abstract Background Micro- and macroarray technologies help acquire thousands of gene expression patterns covering important biological processes during plant ontogeny. Particularly, faithful visualization methods are beneficial for revealing interesting gene expression patterns and functional relationships of coexpressed genes. Such screening helps to gain deeper insights into regulatory behavior and cellular responses, as will be discussed for expression data of developing barley endosperm tissue. For that purpose, high-throughput multidimensional scaling (HiT-MDS, a recent method for similarity-preserving data embedding, is substantially refined and used for (a assessing the quality and reliability of centroid gene expression patterns, and for (b derivation of functional relationships of coexpressed genes of endosperm tissue during barley grain development (0–26 days after flowering. Results Temporal expression profiles of 4824 genes at 14 time points are faithfully embedded into two-dimensional displays. Thereby, similar shapes of coexpressed genes get closely grouped by a correlation-based similarity measure. As a main result, by using power transformation of correlation terms, a characteristic cloud of points with bipolar sandglass shape is obtained that is inherently connected to expression patterns of pre-storage, intermediate and storage phase of endosperm development. Conclusion The new HiT-MDS-2 method helps to create global views of expression patterns and to validate centroids obtained from clustering programs. Furthermore, functional gene annotation for developing endosperm barley tissue is successfully mapped to the visualization, making easy localization of major centroids of enriched functional categories possible.

  2. Regulation of (1,3;1,4)-beta-D-glucan synthesis in developing endosperm of barley lys mutants

    DEFF Research Database (Denmark)

    Christensen, Ulla; Scheller, Henrik Vibe

    2012-01-01

    The mechanism behind altered content of (1,3:1,4)-beta-D-glucan was investigated in developing endosperm of barley lys3 and lys5 mutants. Both types of mutants are primarily affected in starch biosynthesis, and hence effects on (1,3;1,4)-beta-D-glucan are likely to be pleiotropic. The mutant alle...

  3. Golden Rice: introducing the beta-carotene biosynthesis pathway into rice endosperm by genetic engineering to defeat vitamin A deficiency.

    Science.gov (United States)

    Beyer, Peter; Al-Babili, Salim; Ye, Xudong; Lucca, Paola; Schaub, Patrick; Welsch, Ralf; Potrykus, Ingo

    2002-03-01

    To obtain a functioning provitamin A (beta-carotene) biosynthetic pathway in rice endosperm, we introduced in a single, combined transformation effort the cDNA coding for phytoene synthase (psy) and lycopene beta-cyclase (beta-lcy) both from Narcissus pseudonarcissus and both under the control of the endosperm-specific glutelin promoter together with a bacterial phytoene desaturase (crtI, from Erwinia uredovora under constitutive 35S promoter control). This combination covers the requirements for beta-carotene synthesis and, as hoped, yellow beta-carotene-bearing rice endosperm was obtained in the T(0)-generation. Additional experiments revealed that the presence of beta-lcy was not necessary, because psy and crtI alone were able to drive beta-carotene synthesis as well as the formation of further downstream xanthophylls. Plausible explanations for this finding are that these downstream enzymes are constitutively expressed in rice endosperm or are induced by the transformation, e.g., by enzymatically formed products. Results using N. pseudonarcissus as a model system led to the development of a hypothesis, our present working model, that trans-lycopene or a trans-lycopene derivative acts as an inductor in a kind of feedback mechanism stimulating endogenous carotenogenic genes. Various institutional arrangements for disseminating Golden Rice to research institutes in developing countries also are discussed.

  4. Overexpression of the rice carotenoid cleavage dioxygenase 1 gene in Golden Rice endosperm suggests apocarotenoids as substrates in planta.

    Science.gov (United States)

    Ilg, Andrea; Yu, Qiuju; Schaub, Patrick; Beyer, Peter; Al-Babili, Salim

    2010-08-01

    Carotenoids are converted by carotenoid cleavage dioxygenases that catalyze oxidative cleavage reactions leading to apocarotenoids. However, apocarotenoids can also be further truncated by some members of this enzyme family. The plant carotenoid cleavage dioxygenase 1 (CCD1) subfamily is known to degrade both carotenoids and apocarotenoids in vitro, leading to different volatile compounds. In this study, we investigated the impact of the rice CCD1 (OsCCD1) on the pigmentation of Golden Rice 2 (GR2), a genetically modified rice variety accumulating carotenoids in the endosperm. For this purpose, the corresponding cDNA was introduced into the rice genome under the control of an endosperm-specific promoter in sense and anti-sense orientations. Despite high expression levels of OsCCD1 in sense plants, pigment analysis revealed carotenoid levels and patterns comparable to those of GR2, pleading against carotenoids as substrates in rice endosperm. In support, similar carotenoid contents were determined in anti-sense plants. To check whether OsCCD1 overexpressed in GR2 endosperm is active, in vitro assays were performed with apocarotenoid substrates. HPLC analysis confirmed the cleavage activity of introduced OsCCD1. Our data indicate that apocarotenoids rather than carotenoids are the substrates of OsCCD1 in planta.

  5. Barley (Hordeum vulgare L.) low phytic acid 1-1: an endosperm-specific, filial determinant of seed total phosphorus.

    Science.gov (United States)

    Raboy, Victor; Cichy, Karen; Peterson, Kevin; Reichman, Sarah; Sompong, Utumporn; Srinives, Peerasak; Saneoka, Hirofumi

    2014-01-01

    Inositol hexaphosphate (Ins P6 or "phytic acid") typically accounts for 75 (± 10%) of seed total phosphorus (P). In some cases, genetic blocks in seed Ins P6 accumulation can also alter the distribution or total amount of seed P. In nonmutant barley (Hordeum vulgare L.) caryopses, ~80% of Ins P6 and total P accumulate in the aleurone layer, the outer layer of the endosperm, with the remainder in the germ. In barley low phytic acid 1-1 (Hvlpa1-1) seed, both endosperm Ins P6 and total P are reduced (~45% and ~25%, respectively), but germs are phenotypically wild type. This translates into a net reduction in whole-seed total P of ~15%. Nutrient culture studies demonstrate that the reduction in endosperm total P is not due to a reduction in the uptake of P into the maternal plant. Genetic tests (analyses of testcross and F2 seed) reveal that the Hvlpa1-1 genotype of the filial seed conditions the seed total P reduction; sibling seed in the same head of barley that differ in their Hvlpa1-1 genotype (heterozygous vs. homozygous recessive) differ in their total P (normal vs. reduced, respectively). Therefore, Hvlpa1 functions as a seed-specific or filial determinant of barley endosperm total P.

  6. Endosperm degradation during seed development of Echinocystis lobata (Cucurbitaceae) as a manifestation of programmed cell death (PCD) in plants.

    Science.gov (United States)

    Wojciechowska, Marzena; Olszewska, Maria J

    2003-01-01

    Programmed cell death (PCD) is an active, genetically controlled process that ultimately leads to elimination of unnecessary or damaged cells from multicellular organism. It occurs during normal growth and development or in response to a variety of environmental triggers and is indispensable for survival of the organism. In Echinocystis lobata the endosperm, an ephemeral tissue in angiosperm plants, undergoes distinct cytological, physiological and molecular changes during seed development and maturation. As a result, mature seeds are deprived of this tissue. The endosperm was analyzed at the consecutive stages of seed development. The morphological changes of cells were studied at light and electron microscope levels. In this paper we report that endosperm cells undergo morphological and biochemical changes characteristic of apoptosis, a particular type of PCD, i.e. cell shrinkage, chromatin condensation, nuclear fragmentation, and cytoplasm degradation, while the ultrastructure of mitochondria seems to be less changed. Furthermore, the progression of DNA degradation has been shown by agarose gel electrophoresis (ladder pattern of DNA fragmentseparation), TUNEL and comet assay. It isconcluded that during seed maturation, endosperm degradation process is accompanied by typical PCD-related changes of cell morphology and internucleosomal DNA cleavage.

  7. Discrimination of Maize Haploid Seeds from Hybrid Seeds Using Vis Spectroscopy and Support Vector Machine Method.

    Science.gov (United States)

    Liu, Jin; Guo, Ting-ting; Li, Hao-chuan; Jia, Shi-qiang; Yan, Yan-lu; An, Dong; Zhang, Yao; Chen, Shao-jiang

    2015-11-01

    Doubled haploid (DH) lines are routinely applied in the hybrid maize breeding programs of many institutes and companies for their advantages of complete homozygosity and short breeding cycle length. A key issue in this approach is an efficient screening system to identify haploid kernels from the hybrid kernels crossed with the inducer. At present, haploid kernel selection is carried out manually using the"red-crown" kernel trait (the haploid kernel has a non-pigmented embryo and pigmented endosperm) controlled by the R1-nj gene. Manual selection is time-consuming and unreliable. Furthermore, the color of the kernel embryo is concealed by the pericarp. Here, we establish a novel approach for identifying maize haploid kernels based on visible (Vis) spectroscopy and support vector machine (SVM) pattern recognition technology. The diffuse transmittance spectra of individual kernels (141 haploid kernels and 141 hybrid kernels from 9 genotypes) were collected using a portable UV-Vis spectrometer and integrating sphere. The raw spectral data were preprocessed using smoothing and vector normalization methods. The desired feature wavelengths were selected based on the results of the Kolmogorov-Smirnov test. The wavelengths with p values above 0. 05 were eliminated because the distributions of absorbance data in these wavelengths show no significant difference between haploid and hybrid kernels. Principal component analysis was then performed to reduce the number of variables. The SVM model was evaluated by 9-fold cross-validation. In each round, samples of one genotype were used as the testing set, while those of other genotypes were used as the training set. The mean rate of correct discrimination was 92.06%. This result demonstrates the feasibility of using Vis spectroscopy to identify haploid maize kernels. The method would help develop a rapid and accurate automated screening-system for haploid kernels.

  8. Zearalenone contamination in farm maize silage

    OpenAIRE

    L. Cavallarin; Antoniazzi, S.; E. Tabacco; G. Borreani

    2010-01-01

    Whole-plant maize silage, stored in horizontal silos, is the main diet source of lactating dairy cows in Italy. Mycotoxin contamination of maize grain has widely been described (Hussein and Brasel, 2001), while limited information is available on mycotoxins in maize silage (Oldenburg, 1991).

  9. Preferred carbon precursors for lipid labelling in the heterotrophic endosperm of developing oat (Avena sativa L.) grains.

    Science.gov (United States)

    Grimberg, Åsa

    2014-10-01

    Oat (Avena sativa L.) is unusual among the cereal grains in storing high amounts of oil in the endosperm; up to 90% of total grain oil. By using oat as a model species for oil metabolism in the cereal endosperm, we can learn how to develop strategies to redirect carbon from starch to achieve high-oil yielding cereal crops. Carbon precursors for lipid synthesis were compared in two genetically close oat cultivars with different endosperm oil content (about 6% and 10% of grain dw, medium-oil; MO, and high-oil; HO cultivar, respectively) by supplying a variety of (14)C-labelled substrates to the grain from both up- and downstream parts of glycolysis, either through detached oat panicles in vitro or by direct injection in planta. When supplied by direct injection, (14)C from acetate was identified to label the lipid fraction of the grain to the highest extent among substrates tested; 46% of net accumulated (14)C, demonstrating its applicability as a marker for lipids in the endosperm. Time course analyses of injected (14)C acetate during grain development suggested a more efficient transfer of fatty acids from polar lipids to triacylglycerol in the HO as compared to the MO cultivar, and turnover of triacylglycerol was suggested to not play a major role for the final oil content of oat grain endosperm despite the low amount of protective oleosins in this tissue. Moreover, availability of light was shown to drastically affect grain net carbon accumulation from (14)C-sucrose when supplied through detached panicles for the HO cultivar.

  10. Expression analysis of abscisic acid (ABA) and metabolic signalling factors in developing endosperm and embryo of barley.

    Science.gov (United States)

    Chen, Zhiwei; Huang, Jianhua; Muttucumaru, Nira; Powers, Stephen J; Halford, Nigel G

    2013-09-01

    The expression of genes encoding components of ABA and metabolic signalling pathways in developing barley endosperm and embryo was investigated. The genes included HvRCAR35_47387 and HvRCAR35_2538 (encoding ABA receptors), HvABI1d (protein phosphatase 2C), HvSnRK2.4, HvSnRK2.6 and HvPKABA1 (SnRK2-type protein kinases) and HvABI5 (ABA response element binding protein; AREBP), as well as two genes encoding SnRK1-type protein kinases. Both SnRK1 and SnRK2 phosphorylate AREBPs, but SnRK2 is activated by ABA whereas SnRK1 may be broken down. Multiple cereal AREBPs with two conserved SnRK1/2 target sites and another class of BZIP transcription factors with SnRK1/2 binding sites, including HvBLZ1, were identified. Barley grain (cv. Triumph) was sampled at 15, 20, 25 and 30 days post-anthesis (dpa). HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 were expressed highly in the endosperm but at much lower levels in the embryo. Conversely, HvPKABA1 and HvRCAR35_2538 were expressed at higher levels in the embryo than the endosperm, while HvSnRK2.6 was expressed at similar levels in both. HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 all peaked in expression in the endosperm at 20 dpa. A model is proposed in which ABA brings about a transition from a SnRK1-dominated state in the endosperm during grain filling to a SnRK2-dominated state during maturation.

  11. Expression analysis of abscisic acid (ABA) and metabolic signalling factors in developing endosperm and embryo of barley☆

    Science.gov (United States)

    Chen, Zhiwei; Huang, Jianhua; Muttucumaru, Nira; Powers, Stephen J.; Halford, Nigel G.

    2013-01-01

    The expression of genes encoding components of ABA and metabolic signalling pathways in developing barley endosperm and embryo was investigated. The genes included HvRCAR35_47387 and HvRCAR35_2538 (encoding ABA receptors), HvABI1d (protein phosphatase 2C), HvSnRK2.4, HvSnRK2.6 and HvPKABA1 (SnRK2-type protein kinases) and HvABI5 (ABA response element binding protein; AREBP), as well as two genes encoding SnRK1-type protein kinases. Both SnRK1 and SnRK2 phosphorylate AREBPs, but SnRK2 is activated by ABA whereas SnRK1 may be broken down. Multiple cereal AREBPs with two conserved SnRK1/2 target sites and another class of BZIP transcription factors with SnRK1/2 binding sites, including HvBLZ1, were identified. Barley grain (cv. Triumph) was sampled at 15, 20, 25 and 30 days post-anthesis (dpa). HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 were expressed highly in the endosperm but at much lower levels in the embryo. Conversely, HvPKABA1 and HvRCAR35_2538 were expressed at higher levels in the embryo than the endosperm, while HvSnRK2.6 was expressed at similar levels in both. HvRCAR35_47387, HvABI1d, HvSnRK2.4 and HvABI5 all peaked in expression in the endosperm at 20 dpa. A model is proposed in which ABA brings about a transition from a SnRK1-dominated state in the endosperm during grain filling to a SnRK2-dominated state during maturation. PMID:24748715

  12. 454 Transcriptome sequencing suggests a role for two-component signalling in cellularization and differentiation of barley endosperm transfer cells.

    Directory of Open Access Journals (Sweden)

    Johannes Thiel

    Full Text Available BACKGROUND: Cell specification and differentiation in the endosperm of cereals starts at the maternal-filial boundary and generates the endosperm transfer cells (ETCs. Besides the importance in assimilate transfer, ETCs are proposed to play an essential role in the regulation of endosperm differentiation by affecting development of proximate endosperm tissues. We attempted to identify signalling elements involved in early endosperm differentiation by using a combination of laser-assisted microdissection and 454 transcriptome sequencing. PRINCIPAL FINDINGS: 454 sequencing of the differentiating ETC region from the syncytial state until functionality in transfer processes captured a high proportion of novel transcripts which are not available in existing barley EST databases. Intriguingly, the ETC-transcriptome showed a high abundance of elements of the two-component signalling (TCS system suggesting an outstanding role in ETC differentiation. All components and subfamilies of the TCS, including distinct kinds of membrane-bound receptors, have been identified to be expressed in ETCs. The TCS system represents an ancient signal transduction system firstly discovered in bacteria and has previously been shown to be co-opted by eukaryotes, like fungi and plants, whereas in animals and humans this signalling route does not exist. Transcript profiling of TCS elements by qRT-PCR suggested pivotal roles for specific phosphorelays activated in a coordinated time flow during ETC cellularization and differentiation. ETC-specificity of transcriptionally activated TCS phosphorelays was assessed for early differentiation and cellularization contrasting to an extension of expression to other grain tissues at the beginning of ETC maturation. Features of candidate genes of distinct phosphorelays and transcriptional activation of genes putatively implicated in hormone signalling pathways hint at a crosstalk of hormonal influences, putatively ABA and ethylene, and

  13. Vacuolar H+-translocating inorganic pyrophosphatase (Vpp1) marks partial aleurone cell fate in cereal endosperm development.

    Science.gov (United States)

    Wisniewski, Jean-Pierre; Rogowsky, Peter M

    2004-10-01

    Cereal endosperm is a model system for cell fate determination in plants. In wild-type plants the outermost endosperm cells adopt aleurone cell fate, while all underlying cells display starchy endosperm cell fate. Mutant analysis showed that cell fate is determined by position rather than lineage. To further characterise the precise cell fate of the outermost cells, we performed a differential screen and isolated the novel marker gene Vpp1 . It encodes a vacuolar H+-translocating inorganic pyrophosphatase (V-PPase) and is mainly expressed in kernels, leaves and tassels. In kernels, its expression is restricted to the aleurone layer with the maximum of expression shifting from the adaxial to the abaxial side during early stages. Together with three other marker genes Vpp1 was then used to analyse the cell fate of the outermost cells in Dap3 , Dap7 , cr4 and dek1 mutants, all of which have aberrant aleurone layers. In the Dap3 and Dap7 mutants the Vpp1 and Ltp2 markers but not the A1 and Zein markers were expressed in patches without aleurone indicating that the outermost cells had some but not all features of aleurone cells and did not simply adopt starchy endosperm cell fate. A similar result was obtained in the cr4 mutant, although Ltp2 expression was less generalised. In other Dap7 patches characterised by multiple aleurone-like cell layers the expression of Vpp1 and Ltp2 confirmed the aleurone cell fate of the cells in the additional cell layers. The analysis of dek1 mutants confirmed the starchy endosperm cell fate of the majority but not all outermost cells. Based on these data we propose a model suggesting a stepwise commitment to aleurone cell fate. Sequential steps are marked by the expression of Vpp1 , the expression of Ltp2 , the acquisition of a regular shape and thick walls and finally pigmentation coupled with A1 expression.

  14. Maize, tropical (Zea mays L.).

    Science.gov (United States)

    Assem, Shireen K

    2015-01-01

    Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

  15. Marker-assisted breeding for introgression of opaque-2 allele into elite maize inbred line BML-7.

    Science.gov (United States)

    Krishna, M S R; Sokka Reddy, S; Satyanarayana, Sadam D V

    2017-07-01

    Improvement of quality protein maize (QPM) along with high content of lysine and tryptophan had foremost importance in maize breeding program. The efficient and easiest way of developing QPM hybrids was by backcross breeding in marker aided selection. Hence, the present investigation aimed at conversion of elite maize inbred line BML-7 into QPM line. CML-186 was identified to be a donor variety as it revealed high-quality polymorphism with BML-7 for opaque-2 gene specific marker umc1066. Non-QPM inbred line BML-7 was crossed with QPM donor CML-186 and produced F1 followed by the development of BC1F1 and BC2F1 population. Foreground selection was carried out with umc1066 in F1, and selected plants were used for BC1F1 and BC2F1 populations. Two hundred plants were screened in both BC1F1 and BC2F1 population with umc1066 for foreground selection amino acid modifiers. Foreground selected plants for both opaque-2 and amino acid modifiers were screened for background selection for BML-7 genome. Recurrent parent genome (RPG) was calculated for BC2F1 population plants. Two plants have shown with RPG 90-93% in two generation with back cross population. Two BC2F2 populations resulted from marker recognized BC2F1 individuals subjected toward foreground selection followed by tryptophan estimation. The tryptophan and lysine concentration was improved in all the plants. BC2F2 lines developed from hard endosperm kernels were selfed for BC2F2 lines and finest line was selected to illustrate the QPM version of BML-7, with 0.97% of tryptophan and 4.04% of lysine concentration in protein. Therefore, the QPM version of BML-7 line can be used for the development of single cross hybrid QPM maize version.

  16. Differential Synthesis in Vitro of Barley Aleurone and Starchy Endosperm Proteins

    DEFF Research Database (Denmark)

    Mundy, John; Hejgaard, Jørn; Hansen, Annette

    1986-01-01

    To widen the selection of proteins for gene expression studies in barley seeds, experiments were performed to identify proteins whose synthesis is differentially regulated in developing and germinating seed tissues. The in vitro synthesis of nine distinct barley proteins was compared using m......), the alpha-amylase/subtilisin inhibitor (ASI) and the inhibitor of animal cell-free protein synthesis systems (PSI) were synthesized with mRNA from developing starchy endosperm tissue. Of these proteins, beta-amylase, protein Z, and CI- 1 and 2 were also synthesized with mRNA from developing aleurone cells......, but ASI, PSI, and protein C were not. CI-1 and also a probable amylase/protease inhibitor (PAPI) were synthesized at high levels with mRNAs from late developing and mature aleurone. These results show that mRNAs encoding PAPI and CI-1 survive seed dessication and are long-lived in aleurone cells. Thus...

  17. Cutin plays a role in differentiation of endosperm-derived callus of kiwifruit.

    Science.gov (United States)

    Popielarska-Konieczna, Marzena; Kozieradzka-Kiszkurno, Małgorzata; Bohdanowicz, Jerzy

    2011-11-01

    Cutin fluorescence, after auramine O treatment, was detected on the surface of organogenic areas (protuberances) of endosperm derived callus induced on Murashige and Skoog medium with thidiazuron (0.5 mg l(-1)) in darkness. Electron micrographs of the protuberances revealed cuticle, visible as a dark-staining layer, and amorphous waxes on the cell wall. In some cases the cells of the epidermis-like layer and shoot buds at early stages of development showed thick and characteristically wavy cutin. This waviness corresponds with the wrinkled appearance of the cell wall as observed by scanning electron microscopy. The role of multivesicular bodies in cutin production and transfer to the plasma membrane is discussed.

  18. Cell-Wall Carbohydrates of the Endosperm of the Seed of Gleditsia triacanthos.

    Science.gov (United States)

    Manzi, A E; Ancibor, E; Cerezo, A S

    1990-04-01

    The endosperm of the seed of Gleditsia triacanthos L. contains 18.55% of its dry weight as nonreserve, cell-wall carbohydrates. Of this carbohydrate material, comprising mainly mannose, galactose, and glucose, 76.1% was of low-molecular weight or highly hydrophilic. Mannose, galactose, and glucose were also the major sugar components of the polysaccharides extracted with alkali (23.1% of the cell-wall), while the same sugars, with minor amounts of arabinose, form the residues. Methylation analysis of the polysaccharides and the borate-sodium hydroxide residue indicate that the cell walls are built up on a network of galactomannans, with high Man/Gal ratios, reinforced with minor amounts of cellulose.

  19. Cell-Wall Carbohydrates of the Endosperm of the Seed of Gleditsia triacanthos1

    Science.gov (United States)

    Manzi, Adriana E.; Ancibor, Elena; Cerezo, Alberto S.

    1990-01-01

    The endosperm of the seed of Gleditsia triacanthos L. contains 18.55% of its dry weight as nonreserve, cell-wall carbohydrates. Of this carbohydrate material, comprising mainly mannose, galactose, and glucose, 76.1% was of low-molecular weight or highly hydrophilic. Mannose, galactose, and glucose were also the major sugar components of the polysaccharides extracted with alkali (23.1% of the cell-wall), while the same sugars, with minor amounts of arabinose, form the residues. Methylation analysis of the polysaccharides and the borate-sodium hydroxide residue indicate that the cell walls are built up on a network of galactomannans, with high Man/Gal ratios, reinforced with minor amounts of cellulose. Images Figure 2 Figure 2 PMID:16667408

  20. Rice endosperm protein slows progression of fatty liver and diabetic nephropathy in Zucker diabetic fatty rats.

    Science.gov (United States)

    Kubota, Masatoshi; Watanabe, Reiko; Yamaguchi, Miki; Hosojima, Michihiro; Saito, Akihiko; Fujii, Mikio; Fujimura, Shinobu; Kadowaki, Motoni

    2016-10-01

    We previously reported that rice endosperm protein (REP) has renoprotective effects in Goto-Kakizaki rats, a non-obese diabetic model. However, whether these effects occur in obese diabetes remains unclear. This study aimed to clarify the effects of REP on obese diabetes, especially on fatty liver and diabetic nephropathy, using the obese diabetic model Zucker diabetic fatty (ZDF) rats. In total, 7-week-old male ZDF rats were fed diets containing 20 % REP or casein (C) for 8 weeks. Changes in fasting blood glucose levels and urinary markers were monitored during the experimental period. Hepatic lipids and metabolites were measured and renal glomeruli were observed morphologically. HbA1c levels were significantly lower in rats fed REP, compared with C (Pdiabetes, fatty liver and diabetic nephropathy.

  1. CDNA cloning, characterization and expression of an endosperm-specific barley peroxidase

    DEFF Research Database (Denmark)

    Rasmussen, Søren Kjærsgård; Welinder, K.G.; Hejgaard, J.

    1991-01-01

    A barley peroxidase (BP 1) of pI ca. 8.5 and M(r) 37000 has been purified from mature barley grains. Using antibodies towards peroxidase BP 1, a cDNA clone (pcR7) was isolated from cDNA expression library. The nucleotide sequence of pcR7 gave a derived amino acid sequence identical to the 158 C......-terminal amino acid residues of mature BP 1. The clone pcR7 encodes an additional C-terminal sequence of 22 residues, which apparently are removed during processing. BP 1 is less than 50% identical to other sequenced plant peroxidases. Analyses of RNA and protein from aleurone, endosperm and embryo tissue showed...

  2. Differential Synthesis in Vitro of Barley Aleurone and Starchy Endosperm Proteins

    DEFF Research Database (Denmark)

    Mundy, John; Hejgaard, Jørn; Hansen, Annette

    1986-01-01

    RNAs from isolated endosperm and aleurone tissues (developing and mature grain) and from cultured (germinating) aleurone layers treated with abscisic acid (ABA) and GA(3). B and C hordein polypeptides and the salt-soluble proteins beta-amylase, protein Z, protein C, the chymotrypsin inhibitors (CI-1 and 2......To widen the selection of proteins for gene expression studies in barley seeds, experiments were performed to identify proteins whose synthesis is differentially regulated in developing and germinating seed tissues. The in vitro synthesis of nine distinct barley proteins was compared using m......, expression of genes encoding ASI, PSI, protein C, and PAPI is tissue and stage-specific during seed development. Only ASI, CI-1, and PAPI were synthesized in significant amounts with mRNA from cultured aleurone layers. The levels of synthesis of PAPI and CI-1 were independent of hormone treatment...

  3. Transgenic multivitamin corn through biofortification of endosperm with three vitamins representing three distinct metabolic pathways

    Science.gov (United States)

    Naqvi, Shaista; Zhu, Changfu; Farre, Gemma; Ramessar, Koreen; Bassie, Ludovic; Breitenbach, Jürgen; Perez Conesa, Dario; Ros, Gaspar; Sandmann, Gerhard; Capell, Teresa; Christou, Paul

    2009-01-01

    Vitamin deficiency affects up to 50% of the world's population, disproportionately impacting on developing countries where populations endure monotonous, cereal-rich diets. Transgenic plants offer an effective way to increase the vitamin content of staple crops, but thus far it has only been possible to enhance individual vitamins. We created elite inbred South African transgenic corn plants in which the levels of 3 vitamins were increased specifically in the endosperm through the simultaneous modification of 3 separate metabolic pathways. The transgenic kernels contained 169-fold the normal amount of β-carotene, 6-fold the normal amount of ascorbate, and double the normal amount of folate. Levels of engineered vitamins remained stable at least through to the T3 homozygous generation. This achievement, which vastly exceeds any realized thus far by conventional breeding alone, opens the way for the development of nutritionally complete cereals to benefit the world's poorest people. PMID:19416835

  4. Global maize production, utilization, and consumption.

    Science.gov (United States)

    Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves

    2014-04-01

    Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification.

  5. Maize (Zea Mays L landraces from the southern region of Brazil: contamination by Fusarium sp, zearalenone, physical and mechanical characteristics of the kernels

    Directory of Open Access Journals (Sweden)

    Tatiana Roselena de Oliveira

    2009-11-01

    Full Text Available This work had as objectives the study of the physical and mechanical characteristics of maize kernels in relation to the contamination by Fusarium sp and by zearalenone in twenty landraces of maize from the southern region of Brazil. From the analyzed samples, 60 % has been considered to have a hard endosperm type and 40 % an intermediary one. A correlation between the physical and mechanical variables was observed as an indication that the higher is the proportion of hard endosperm, more dense will be the kernel and more force for its rupture will be necessary. The level of contamination by Fusarium sp was between 5.5 and 24.75% among the analyzed grains, correlating positively with the flotation index, indicating that the landraces of maize with a softer endosperm can present a higher contamination by this genus. The presence of zearalenone was verified in 75 % of the samples, in concentrations varying from 50 to 640 µg kg-1.Este trabalho teve por objetivos verificar as características físicas, mecânicas, contaminação por Fusarium sp e por zearalenona e suas relações, em vinte variedades crioulas de milho da região sul do Brasil. Verificou-se que das amostras analisadas, 60% foram consideradas como possuidoras de endosperma do tipo duro e 40% com endosperma do tipo intermediário. As variáveis físicas e mecânicas se correlacionaram, indicando que quanto maior a proporção de endosperma vítreo, mais denso e maior a força necessária até a ruptura do grão. A contaminação por Fusarium sp esteve entre 5,5% e 24,75% nos grãos analisados, correlacionando-se positivamente com o índice de flotação, indicando que as variedades crioulas de milho com uma maior proporção de endosperma macio podem apresentar uma maior contaminação por Fusarium sp, sugerindo-se a utilização de variedades crioulas com a textura do endosperma predominantemente vítrea. A presença de zearalenona foi verificada em 75% das amostras, em concentra

  6. Identification of Discriminant Factors after Exposure of Maize and Common Bean Plantlets to Abiotic Stresses

    Directory of Open Access Journals (Sweden)

    Lázaro HERNÁNDEZ

    2015-12-01

    Full Text Available Adverse environmental conditions limit crop yield and better understanding of plant response to stress will assist the development of more tolerant cultivars. Maize and common bean plantlets were evaluated under salinity, high temperature, drought and waterlogged conditions to identify biochemical markers which could be useful for rapid identification of putative stress tolerant plants. The levels of phenolics (free, cell wall-linked, total, aldehydes including malondialdehyde and chlorophylls (a, b, total were measured on stressed plantlets.  Only two indicators were statistically non-significant:  chlorophyll b in maize plantlets stressed with sodium chloride and malondialdehyde content in drought stressed maize. The most remarkable effects of abiotic stresses can be summarized as follows: (i salinity increased levels of free phenolics in maize plantlets and chlorophylls (a, b, total in common bean; (ii high temperature (40 °C elevated levels of chlorophylls (a, b, total in maize but decreased chlorophylls (a, b, total and free phenolics in common bean; (iii drought increased phenolics and decreased chlorophylls (a, b, total in maize and increased chlorophyll pigments (a, b, total in common bean; (iv waterlogging increased free phenolics and decreased chlorophylls (a, b, total in maize and increased chlorophyll (a, total in common bean. Free phenolics and chlorophylls, especially a, were the most responsive indicators to stress and can, therefore, be considered putative biochemical markers for abiotic stress tolerance in maize and common bean. The use of Fisher’s linear discriminant analysis to differentiate non-stressed and stressed plants in breeding programs is also a novel aspect of this report. Fisher’s linear discriminant functions classified correctly 100% of non-stressed or stressed originally grouped plants.

  7. ZCN8 encodes a potential orthologue of Arabidopsis FT florigen that integrates both endogenous and photoperiod flowering signals in maize.

    Science.gov (United States)

    Lazakis, Chloë M; Coneva, Viktoriya; Colasanti, Joseph

    2011-10-01

    Higher plants use multiple perceptive measures to coordinate flowering time with environmental and endogenous cues. Physiological studies show that florigen is a mobile factor that transmits floral inductive signals from the leaf to the shoot apex. Arabidopsis FT protein is widely regarded as the archetype florigen found in diverse plant species, particularly in plants that use inductive photoperiods to flower. Recently, a large family of FT homologues in maize, the Zea CENTRORADIALIS (ZCN) genes, was described, suggesting that maize also contains FT-related proteins that act as a florigen. The product of one member of this large family, ZCN8, has several attributes that make it a good candidate as a maize florigen. Mechanisms underlying the floral transition in maize are less well understood than those of other species, partly because flowering in temperate maize is dependent largely on endogenous signals. The maize indeterminate1 (id1) gene is an important regulator of maize autonomous flowering that acts in leaves to mediate the transmission or production of florigenic signals. This study finds that id1 acts upstream of ZCN8 to control its expression, suggesting a possible new link to flowering in day-neutral maize. Moreover, in teosinte, a tropical progenitor of maize that requires short-day photoperiods to induce flowering, ZCN8 is highly up-regulated in leaves under inductive photoperiods. Finally, vascular-specific expression of ZCN8 in Arabidopsis complements the ft-1 mutation, demonstrating that leaf-specific expression of ZCN8 can induce flowering. These results suggest that ZCN8 may encode a florigen that integrates both endogenous and environmental signals in maize.

  8. Breaking through the Endosperm during Seed Germination%种子萌发过程中胚乳的突破性研究

    Institute of Scientific and Technical Information of China (English)

    徐振江; 陈兵先; 赵晟楠; 袁红霞; 郜珊珊; 张瑜; 陈靖; 王晓峰

    2012-01-01

    Endosperm completely encloses the embryo of many seeds and is a mechanical restraint for the completion of germination. Thus, rupture of the endosperm is the last key step controlling the process of germination. Rupture of the endosperm requires the growth potential of embryo and weakening of the endosperm after imbibition. Weakening of the endosperm involves enzymatic and non-enzymatic mechanisms. This review summarizes research progress in growth potential of embryo, location and ways of endosperm rupture, structure of the endosperm and chemical composition of endosperm cell walls, roles of cell-wall-degrading enzymes, ex-pansin and reactive oxygen species.%胚乳将许多种子的胚完全包裹,是这些种子萌发的物理屏障,其破裂与否是决定种子萌发与否的最后开关.胚乳破裂是胚生长产生由内向外“顶”的机械力量以及胚乳组织本身机械强度下降(胚乳弱化)的共同结果,而胚乳弱化则包括细胞壁的酶促和非酶促松弛机制.本文综述胚生长产生的机械力量、胚乳破裂的部位和方式、胚乳的组织结构及其细胞壁的化学组成、各种细胞壁降解酶及非酶的扩展蛋白(expansin)和活性氧在胚乳弱化中的作用等方面的研究进展.

  9. Maize starch biphasic pasting curves

    CSIR Research Space (South Africa)

    Nelles, EM

    2000-05-01

    Full Text Available (150–500 rev/min). The second pasting peak is attributed to the formation of complexes between amylose and low levels of lipid present in maize starch. When lipid was partially removed by extraction with methanol-chloroform (1: 3 v/v), the second...

  10. ZEA MAIZE: A MODERN CRAZE

    Directory of Open Access Journals (Sweden)

    Dhamija Isha

    2013-06-01

    Full Text Available Zea stands for ‘sustaining life’ and Mays stands for ‘life giver’. Zea mays is one of the oldest and most dynamic crop species, which has gained popularity in modern world too, due to its applications in diverse dishes. Corn is produced in every continent of the world with the exception of Antarctica. It is an annual monoecious sunny plant, surviving perfectly in nutrient rich, well-drained soil. Each and every part of the corn, from husk to corn silk is beneficial for the society. There are more than 3,500 different uses for corn products. Corn does much more than feed people and livestock. The plant contains alkaloids, flavonoids, saponins, maizenic acid, vitamins B1, K and minerals like potassium, phosphorous and zinc. Traditionally, Maize is used as an analgesic, anti-diarrheal, anti-prostatitic, anti-lithiasis, anti-tumor, anti-hypertensive, anti-diabetic, anti-hyperlipidemic, anti-inflammatory and anti-oxidant. In this review article, we have narrated miscellaneous uses of corn varieties and described the pharmacological activities, phytoconstituents, nutritional value and traditional uses of maize. The maize has assorted uses like culinary, medicinal and industrial. Corn dishes like corn-meal, corn-flakes, popcorn, “makki ki roti” and corn soup highlight its dominance all over the world. Therefore, maize has become a craze among modern youth.

  11. Combing Ability Analysis ofamong Early Generation Maize Inbred ...

    African Journals Online (AJOL)

    dagne.cimdom

    Combining ability estimates are important genetic attributes ina maize breeding ... Twenty-nine early generation maize inbred lines were crossed to two ...... agronomic traits in quality protein maize under stress and non stress environments.

  12. An Ac transposon system based on maize chromosome 4S for isolating long-distance-transposed Ac tags in the maize genome.

    Science.gov (United States)

    Wang, Fei; Li, Zhaoying; Fan, Jun; Li, Pengfei; Hu, Wei; Wang, Gang; Xu, Zhengkai; Song, Rentao

    2010-12-01

    Transposon tagging is an important tool for gene isolation and functional studies. In maize, several transposon-tagging systems have been developed, mostly using Activator/Dissociation (Ac/Ds) and Mutator systems. Here, we establish another Ac-based transposon system with the donor Ac tightly linked with sugary1 (su1) on maize chromosome 4S. Newly transposed Ac (tr-Acs) were detected based on a negative dosage effect, and long-distance-transposed Ac events were identified and isolated from the donor Ac by a simple backcross scheme. In this study, we identified 208 independent long-distance-transposed Ac lines. Thirty-one flanking sequences of these tr-Acs were isolated and localized in the maize genome. As found in previous studies, the tr-Acs preferentially inserted into genic sequences. The distribution of tr-Acs is not random. In our study, the tr-Acs preferentially transposed into chromosomes 1, 2, 9 and 10. We discuss the preferential distribution of tr-Acs from Ac systems. Our system is complementary to two other Ac-based regional-mutagenesis systems in maize, and the combined use of these systems will achieve an even and high-density distribution of Ac elements throughout the maize genome for functional-genomics studies.

  13. Embryo and endosperm development in caryopses of hybrids from crosses between tetraploid wheats and their alloplasmic lines with rye

    Directory of Open Access Journals (Sweden)

    Wijciech Sodkiewicz

    2014-01-01

    Full Text Available Data concerning the embryo and endosperm development in twenty-day-old caryopses of hybrids obtained as the result of pollination with rye pollen of tetraploid wheats (Triticum dicoccoides, T. dicoccum, T. durum and T. polonicum, their alloplasmic lines with T. timopheevi plasma and aIlaplasmic T. timopheevi lines with cytoplasma of the above mentioned tetraploid wheats and hexaploid wheat (T. macha were analysed. A high variability was noted between the tetraploid wheats as regards the degree of development of the embryo and of the endosperm in the hybrid caryopses and a decisive influence of the wheat genotype on these characters. The data for alloplasmic lines showed that the cytoplasm may have a modifying effect on the expression of these genotype characters.

  14. Genomic imprinting in plants: what makes the functions of paternal and maternal genes different in endosperm formation?

    Science.gov (United States)

    Ohnishi, Takayuki; Sekine, Daisuke; Kinoshita, Tetsu

    2014-01-01

    Genomic imprinting refers to the unequal expression of maternal and paternal alleles according to the parent of origin. This phenomenon is regulated by epigenetic controls and has been reported in placental mammals and flowering plants. Although conserved characteristics can be identified across a wide variety of taxa, it is believed that genomic imprinting evolved independently in animal and plant lineages. Plant genomic imprinting occurs most obviously in the endosperm, a terminally differentiated embryo-nourishing tissue that is required for seed development. Recent studies have demonstrated a close relationship between genomic imprinting and the development of elaborate defense mechanisms against parasitic elements during plant sexual reproduction. In this chapter, we provide an introductory description of genomic imprinting in plants, and focus on recent advances in our understanding of its role in endosperm development, the frontline of maternal and paternal epigenomes.

  15. Isolation of Promoters and Fragments of Genes Controlling Endosperm Development Without Fertilization in Arabidopsis and Engineering of the Antisense Constructions

    Directory of Open Access Journals (Sweden)

    Grigory A. Gerashchenkov

    2015-06-01

    Full Text Available Apomixis is asexual seed reproduction without both meiosis and fertilization based on the complex developmental processes such as apomeiosis, parthenogenesis and specific endosperm development. This investigation is aimed at engineering of apomixis in Arabidopsis thaliana with sexual seed reproduction. The fragments of known genes of endosperm formation MEA, FIE, FIS2 and gene of apomeiosis DYAD (as control were isolated using Q5 high fidelity DNA polymerase. These gene fragments of interest at the antisense orientation were fused with isolated constitutive and meiosis specific promoters of Arabidopsis at NcoI sites. The fused promoter-gene fragment modules were cloned in pCambia1301 at SalI cites. The engineered constructions will be used for the floral dip transformation of Arabidopsis and down regulation of these genes at engineering of apomixis.

  16. Cross-incompatibility between maize and teosinte

    Energy Technology Data Exchange (ETDEWEB)

    Kermicle, J.L.; Allen, J.O. (Univ. of Wisconsin, Madison (United States))

    1990-01-01

    Pollen of dent maize was unable to fertilize plants representing five of six accessions of Zea mays ssp. mexicana teosinte and the one accession of ssp. huehuetenangensis teosinte tested. Plants from all other teosinte taxa were successfully fertilized by dent maize. Factors governing cross-incompatibility from ssp. mexicana accessions Central Plateau 48703 and Chalco were incorporated into dent inbred W22 by backcrossing. The Chalco-derived strain behaves like cross-incompatible popcorns (Ga1-s Ga1-s) in that it does not allow fertilization by dent pollen (ga1), is reciprocally compatible with Ga1-carrying strains and distorts sugary-1 ratios when trans heterozygotes are self-pollinated. Its ability to pollinate Ga1-s Ga1-s plants segregates as an allele of Ga1. Pollen from the Central Plateau-derived stock also functions on Ga1-s Ga1-s silks, but the reciprocal cross, as well as pollination with ga1 ga1, fails. Hybrids of this stock with dent also do not set seed when pollinated with either ga1 or Ga1-s pollen. Compatibility is governed in this case by a complex of chromosome 4 factors designated TIC-CP. One component of the complex is a cross-neutral allele of Ga1, denoted Ga1-m:CPT, that permits pollen carrying it to function on Ga1-s Ga1-s silks. A second factor, located 4 map units distal to su1, permits pollen to function on silks carrying TIC-CP. Expression of the TIC-UP barrier in the style requires at least one other linked factor. Curiously, homozygous TIC-CP plants often fertilize themselves poorly.

  17. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Directory of Open Access Journals (Sweden)

    Julien De Giorgi

    2015-12-01

    Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  18. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Science.gov (United States)

    De Giorgi, Julien; Piskurewicz, Urszula; Loubery, Sylvain; Utz-Pugin, Anne; Bailly, Christophe; Mène-Saffrané, Laurent; Lopez-Molina, Luis

    2015-12-01

    Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA) and abscisic acid (ABA) signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  19. Effect of Flowering Time of Spikelets Within a Rice Panicle on Endosperm Deve lopment and Its Physiological Mechanism

    Institute of Scientific and Technical Information of China (English)

    Yang Jianchang; Liu Lijun; Wang Zhiqin; Lang Youzhong; Zhu Qingsen

    2000-01-01

    The flowering duration of spikelets within a panicle of the rice cultivars of Wuyujing 3 (Japonica), Yangdao 4 (Indica), Shanyou 63 (Indica hybrid rice) and PC311/Zaoxiandang 18 (Indica/japonica hybrid rice) was 5d, 7d, 7d and 8d, respectively. The spikelets flowered on the 2nd day produced the highest endosperm weight (EW) and the most endosperm cells (ECs), and followed by the spikelets flowered on the 1st day. ECs decreased with the delay of flowering of the spikelets flowered from the 3rd day. Within a variety or a hybrid combination, the difference in endosperm cell weight (ECW) was not significant among the grains flowered on different dates. EW and grain-filled percentage (G-FP) were very significantly correlated with ECs, but not with ECW. The earlier the spikelets flowered (except those flowered on the 1st day), the greater the initial proliferation power (R°), the higher the maximum proliferation rate (Vmax) and the higher the mean proliferation rate (V) of ECs, and the shorter the time reaching Vmax, and vice versa. R°, Vmax,V and ECs were significantly correlated with the physiological activities (ATPase activity and the content of spermidine and spermine) of the grains at early grain filling stage. The physiological activities of the grains, R°,Vmax,V, ECs and EW significantly increased after removing 1/2 plants at booting stage and spraying 6-BA 〔N6(benzyl) adenine〕 at early heading stage, and the results were reversed after cutting 1/2 leaves at booting stage. These results suggest that the difference in ECs results in the difference in the grain weight, while the low physiological activities of late-flowered grains are the important reasons for their poor endosperm development.

  20. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination

    Science.gov (United States)

    Loubery, Sylvain; Utz-Pugin, Anne; Bailly, Christophe; Mène-Saffrané, Laurent; Lopez-Molina, Luis

    2015-01-01

    Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA) and abscisic acid (ABA) signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties. PMID:26681322

  1. Involvement of reactive oxygen species in endosperm cap weakening and embryo elongation growth during lettuce seed germination.

    Science.gov (United States)

    Zhang, Yu; Chen, Bingxian; Xu, Zhenjiang; Shi, Zhaowan; Chen, Shanli; Huang, Xi; Chen, Jianxun; Wang, Xiaofeng

    2014-07-01

    Endosperm cap (CAP) weakening and embryo elongation growth are prerequisites for the completion of lettuce seed germination. Although it has been proposed that the cell wall loosening underlying these processes results from an enzymatic mechanism, it is still unclear which enzymes are involved. Here it is shown that reactive oxygen species (ROS), which are non-enzymatic factors, may be involved in the two processes. In Guasihong lettuce seeds imbibed in water, O2·(-) and H2O2 accumulated and peroxidase activity increased in the CAP, whereas its puncture force decreased. In addition, in the radicle, the increase in embryo growth potential was accompanied by accumulation of O2·(-) and an increase in peroxidase activity. Imbibing seeds in 0.3% sodium dichloroisocyanurate (SDIC) reduced endosperm viability and the levels of O2·(-), H2O2, and peroxidase activity in the CAP, whereas the decrease in its puncture force was inhibited. However, in the embryo, SDIC did not affect the accumulation of O2·(-), peroxidase activity, and the embryo growth potential. As a result, SDIC caused atypical germination, in which the endosperm ruptured at the boundary between the CAP and lateral endosperm. ROS scavengers and ROS generation inhibitors inhibited the CAP weakening and also decreased the embryo growth potential, thus decreasing the percentage of seed germination. Exogenous ROS and ROS generation inducers increased the percentage of CAP rupture to some extent, and the addition of H2O2 to 0.3% SDIC enabled some seeds to undergo typical germination. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    OpenAIRE

    Buddhi Bahadur Achhami; Santa Bahadur BK; Ghana Shyam Bhandari

    2015-01-01

    Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage per...

  3. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    OpenAIRE

    Buddhi Bahadur Achhami; Santa Bahadur BK; Ghana Shyam Bhandari

    2015-01-01

    Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage...

  4. Effect of winter maize-based intercropping systems on maize yield, associated weeds and economic efficiency

    OpenAIRE

    2014-01-01

    A field experiment was conducted during winter seasons of 2003-04 and 2004-05 at Kanpur, India to study the effect of winter maize (Zea mays L.) based intercropping systems on maize yield, associated weeds and economics under irrigated condition of central Uttar Pradesh. Thirteen maize-based cropping systems such as maize sole, potato (Solanum tuberosum L.) sole, mustard [Brassica juncea (L.) Czernj. & Cosson] sole, toria (Brassica campestris var. toria) sole, pea (Pisum sativum L.) sole, lin...

  5. Effects of variations in culture media and hormonal treatments upon callus induction potential in endosperm explant of Barringtonia racemosa L.

    Institute of Scientific and Technical Information of China (English)

    Nurul Izzati Osman; Norrizah Jaafar Sidik; Asmah Awal

    2016-01-01

    Objective: To induce callus from the medicinally valuable species, Barringtonia racemosa L.(B. racemosa) whereby the formation of callus is essential for micropropagation studies and in vitro plant secondary metabolites production.Methods: The callus induction potential in B. racemosa was assessed from endosperm explant cultured on different culture media and plant hormonal treatments. Lloyd and Mc Cown’s woody plant medium and Murashige and Skoog’s medium were used in the study as culture media. On the other hand, various concentrations and combinations of2,4-dichlorophenoxyacetic acid(1.0–2.0 mg/L) and kinetin(0.5–2.5 mg/L) had been incorporated in the culture media to exert the effects of auxin and cytokinin on callus induction.Results: From the present study, it was found that the profuse [(1.681 ± 0.770) g fresh weight,(0.239 ± 0.239) g dry weight] and friable callus formation was optimally produced with desirable morphology and considerable percentage of callus induction(56.70%) in endosperm explants cultured on 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 1.5 mg/L kinetin in Murashige and Skoog’s medium.Conclusions: A reliable protocol for inducing callus formation of profuse and friable morphology in endosperm explant of B. racemosa had therefore been successfully established.

  6. Effect of gamma-radiation and microwave heating on endosperm microstructure in relation to some technological properties of wheat grain.

    Science.gov (United States)

    Błaszczak, W; Gralik, J; Klockiewicz-Kamińska, E; Fornal, J; Warchalewski, J R

    2002-04-01

    Grains of the Polish winter wheat variety Begra were subject to gamma-radiation (60Co) within the dose range of 0.05-10 kGy and microwave treatment from 15 to 180 s, the latter resulting in a bulk grain temperature ranging from 28 to 98 degrees C. Both processes were responsible for marked structural changes of wheat kernel endosperm and were pronounced with increasing dose of ionizing radiation or with prolonged time of microwave treatment. Endosperm microstructures of wheat kernels treated with gamma-radiation ranging from 0.05 to 0.5 kGy did not differ from that of untreated ones. Only some changes in the structure of starch granules and proteins were observed at doses of 1, 5 and 10 kGy. Simultaneously at the doses of 5 and 10 kGy a statistically significant decrease of falling number, sodium dodecyl sulfate (SDS) sedimentation values, dough stability and energy were observed, while dough weakening progressed. Microwave treatment longer than 90 s caused marked changes in kernel endosperm structure. Some changes of proteins caused by denaturation created visible fibrils as well as high swelling and deformation of starch granules. This was followed by an increase in the falling number value, decrease in the estimated results of SDS sedimentation test, lowering of the percent of gluten washed out and of the dough energy, respectively. Also a significant decrease in bread quality expressed by volume and score was observed with increasing time of exposure to microwave.

  7. Starch-Branching Enzyme I-Deficient Mutation Specifically Affects the Structure and Properties of Starch in Rice Endosperm1

    Science.gov (United States)

    Satoh, Hikaru; Nishi, Aiko; Yamashita, Kazuhiro; Takemoto, Yoko; Tanaka, Yasumasa; Hosaka, Yuko; Sakurai, Aya; Fujita, Naoko; Nakamura, Yasunori

    2003-01-01

    We have isolated a starch mutant that was deficient in starch-branching enzyme I (BEI) from the endosperm mutant stocks of rice (Oryza sativa) induced by the treatment of fertilized egg cells with N-methyl-N-nitrosourea. The deficiency of BEI in this mutant was controlled by a single recessive gene, tentatively designated as starch-branching enzyme mutant 1 (sbe1). The mutant endosperm exhibited the normal phenotype and contained the same amount of starch as the wild type. However, the mutation apparently altered the fine structure of amylopectin. The mutant amylopectin was characterized by significant decrease in both long chains with degree of polymerization (DP) ≥ 37 and short chains with DP 12 to 21, marked increase in short chains with DP ≤ 10 (A chains), and slight increase in intermediate chains with DP 24 to 34, suggesting that BEI specifically synthesizes B1 and B2–3 chains. The endosperm starch from the sbe1 mutant had a lower onset concentration for urea gelatinization and a lower onset temperature for thermo-gelatinization compared with the wild type, indicating that the genetic modification of amylopectin fine structure is responsible for changes in physicochemical properties of sbe1 starch. PMID:14526120

  8. Temperature Stress at Grain Filling Stage Mediates Expression of Three Isoform Genes Encoding Starch Branching Enzymes in Rice Endosperm

    Institute of Scientific and Technical Information of China (English)

    WEI Ke-su; CHENG Fang-min; ZHANG Qi-fang; LIU Kui-gang

    2009-01-01

    An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures (32oC for high temperature and 22oC for optimum temperature) at the grain filling stage in plant growth chambers, and the different expressions of three isoform genes (SBEI, SBEIII and SBEIV) encoding starch branching enzyme (SBE) in the endosperms were studied by the real-time fluorescence quantitative PCR (FQ-PCR) method. Effects of high temperature on the SBE expression in developing rice endosperms were isoform-dependent. High temperature significantly down-regulated the expressions of SBEI and SBEIII, while up-regulated the expression of SBEIV. Compared with SBEIV and SBEIII, the expression of SBEI gene in Zhefu 49 rice endosperms was more sensitive to temperature variation at the grain filling stage. This study indicates that changes in weather/climate conditions especially temperature stress influence rice grain formation and its quality as evidenced by isoform expression.

  9. MaizeGDB: Global support for maize research through open access information [abstract

    Science.gov (United States)

    MaizeGDB is the open-access global repository for maize genetic and genomic information – from single genes that determine nutritional quality to whole genome-scale data for complex traits including yield and drought tolerance. The data and tools at MaizeGDB enable researchers from Ethiopia to Ghan...

  10. Long-term Effects of Early Life Maize Yield on Maize Productivity and Efficiency in Rural Malawi

    OpenAIRE

    2017-01-01

    The paper assesses the effects of maize yields just prior to birth (in utero), in the first and the second years of life on adult life productivity and efficiency of maize farmers born between 1984 and 1995 in rural Malawi. To ensure that early life maize yields are not confounded by omitted local chacteristics, they are transformed into relative maize yields by using a cumulative gamma distribution. I find that maize yield just prior to birth significantly increases maize output in a farmer'...

  11. Importance of amylases for physiological quality in maize seeds

    Directory of Open Access Journals (Sweden)

    Camila Aparecida Lopes

    2017-09-01

    Full Text Available Seed quality is the result of the sum of genetic, physical, physiological and sanitary attributes that affect seed ability to perform vital functions related to germination, vigor, and longevity. The expression of genes associated with physiological quality can be assessed by means of germination and vigor analyses, as well as by transcript and protein analyses. The objective in this work was to review the relevance of amylase group enzymes to the physiological quality of maize seeds. Within this group, α-amylase (1,4-α-D-glucan glucanohydrolase E.C 3.2.1.1 plays an important role in starch hydrolysis, and is responsible for 90% of the amylolytic activity in maize seeds. It is responsible for starch conversion into sugars (e.g., destrin, which is used for embryo growth. β-amylase (1,4-α-D-glucan maltohydrolase E.C 3.2.1.2 catalyzes the release of maltose and dextrins from the non-reducing ends of starch. Research has shown that amylase enzymes are directly linked to physiological quality of maize seeds. Alpha- and beta-amylases are mainly involved in the germination process and seed heterosis, and can also be used as molecular markers associated with seed tolerance for drying.

  12. "Achieving Mexico’s Maize Potential"

    OpenAIRE

    Antonio Turrent Fernández; Timothy A. Wise; Elise Garvey

    2012-01-01

    Rising agricultural prices, combined with growing import dependence, have driven Mexico’s food import bill over $20 billion per year and increased its agricultural trade deficit. Mexico imports one-third of its maize, overwhelmingly from the United States, but three million producers grow most of the country’s white maize, which is used primarily for tortillas and many other pluricultural products for human consumption. Yield gaps are large among the country’s small to medium-scale maize farm...

  13. Presence of deoxynivalenol in maize of Vojvodina

    OpenAIRE

    Jajić Igor M.; Abramović Biljana F.; Jurić Verica B.; Krstović Saša Z.

    2007-01-01

    By applying previously established optimal conditions for the determination of deoxynivalenol (DON) by liquid chromatography with DAD detector, in this work, its content was determined in maize samples collected during the past 3 years (2004-2006) from different locations in Vojvodina. Analyzing 103 maize samples in total, the presence of deoxynivalenol was established in 42.7% of the samples. Only 3 samples of maize contained DON in concentrations that exceeded the maximum permitted level (1...

  14. Maize genome sequencing by methylation filtration.

    Science.gov (United States)

    Palmer, Lance E; Rabinowicz, Pablo D; O'Shaughnessy, Andrew L; Balija, Vivekanand S; Nascimento, Lidia U; Dike, Sujit; de la Bastide, Melissa; Martienssen, Robert A; McCombie, W Richard

    2003-12-19

    Gene enrichment strategies offer an alternative to sequencing large and repetitive genomes such as that of maize. We report the generation and analysis of nearly 100,000 undermethylated (or methylation filtration) maize sequences. Comparison with the rice genome reveals that methylation filtration results in a more comprehensive representation of maize genes than those that result from expressed sequence tags or transposon insertion sites sequences. About 7% of the repetitive DNA is unmethylated and thus selected in our libraries, but potentially active transposons and unmethylated organelle genomes can be identified. Reverse transcription polymerase chain reaction can be used to finish the maize transcriptome.

  15. Purification and characterization of the maize amyloplast stromal 112-kDa starch phosphorylase.

    Science.gov (United States)

    Mu, H H; Yu, Y; Wasserman, B P; Carman, G M

    2001-04-01

    A plastidic 112-kDa starch phosphorylase (SP) has been identified in the amyloplast stromal fraction of maize. This starch phosphorylase was purified 310-fold from maize endosperm and characterized with respect to its enzymological and kinetic properties. The purification procedure included ammonium sulfate fractionation, Sephacryl 300 HR chromatography, affinity starch adsorption, Q-Sepharose, and Mono Q chromatography. The procedure resulted in a nearly homogeneous enzyme preparation as determined by native and SDS-polyacrylamide gel electrophoresis. Anti-SP antibodies recognized the purified 112-kDa SP enzyme and N-terminal amino acid sequence analysis confirmed that the purified enzyme is the amyloplast stromal 112-kDa SP. Analysis of the purified enzyme by Superose 6 gel filtration chromatography indicated that the native enzyme consisted of two identical subunits. The pH optimum for the enzyme was 6.0 in the synthetic direction and 5.5 in the phosphorolytic direction. SP activity was inhibited by thioreactive agents, diethyl pyrocarbonate, phenylglyoxal, and ADP-glucose. The activation energies for the synthetic and phosphorolytic reactions were 11.1 and 16.9 kcal/mol, respectively, and the enzyme was thermally labile above 50 degrees C. Results of kinetic experiments indicated that the enzyme catalyzes its reaction via a sequential Bi Bi mechanism. The Km value for amylopectin was eight-fold lower than that of glycogen. A kinetic analysis indicated that the phosphorolytic reaction was favored over the synthetic reaction when malto-oligosaccharides (4 to 7 units) were used as substrates. The specificity constants (Vmax/Km) of the enzyme measured in either the synthetic or the phosphorolytic directions increased with increasing chain length.

  16. The keratin intermediate filament—like system in maize protoplasts

    Institute of Scientific and Technical Information of China (English)

    SuFei; GuWei; 等

    1990-01-01

    The application of Penman's method of cell fractionation to plant protoplasts leads to our finding of keratin intermediate filament(IF)-like system in maize protoplasts,which was identified by using immunogold labelling with monoclonal antibody of cytokeratin from animal cells.Many gold particles were found to be bound on filaments,linked by 3 nm filaments.After further digestion and extraction with DNase I and ammonium sulphate.IF-like framework-lamina-nuclear matrix system was shown under electron microscope.That IF system exists in plant protoplasts just like in animal cells,and their main component is keratin-like protein.

  17. Block-surface staining for differentiation of starch and cell walls in wheat endosperm.

    Science.gov (United States)

    Glenn, G M; Pitts, M J; Liao, K; Irving, D W

    1992-03-01

    A staining technique for differentiating starch granules and cell walls was developed for computer-assisted studies of starch granule distribution in cells of wheat (Triticum aestivum L.) caryopses. Blocks of embedded caryopses were sectioned, exposing the endosperm tissue, and stained with iodine potassium iodide (IKI) and Calcofluor White. Excessive tissue hydration during staining was avoided by using stains prepared in 80% ethanol and using short staining times. The IKI quenched background fluorescence which facilitated the use of higher concentrations of Calcofluor White. Cell wall definition was improved with the IKI-Calcofluor staining combination compared to Calcofluor alone. The high contrast between darkly stained starch granules and fluorescent cell walls permitted computer assisted analysis of data from selected hard and soft wheat varieties. The ratio of starch granule area to cell area was similar for both wheat classes. The starch granule sizes ranged from 2.1 microns 3 to 22,000 microns 3 with approximately 90% of the granules measuring less than 752 microns 3 (ca. 11 microns in diameter). Hard wheat samples had a greater number of small starch granules and a lower mean starch granule area compared to the soft wheat varieties tested. The starch size distribution curve was bimodal for both the hard and soft wheat varieties. Three-dimensional starch size distribution was measured for four cells near the central cheek region of a single caryopsis. The percentage of small granules was higher at the ends than at the mid-section of the cells.

  18. Transgenic Production of an Anti HIV Antibody in the Barley Endosperm.

    Directory of Open Access Journals (Sweden)

    Goetz Hensel

    Full Text Available Barley is an attractive vehicle for producing recombinant protein, since it is a readily transformable diploid crop species in which doubled haploids can be routinely generated. High amounts of protein are naturally accumulated in the grain, but optimal endosperm-specific promoters have yet to be perfected. Here, the oat GLOBULIN1 promoter was combined with the legumin B4 (LeB4 signal peptide and the endoplasmic reticulum (ER retention signal (SEKDEL. Transgenic barley grain accumulated up to 1.2 g/kg dry weight of recombinant protein (GFP, deposited in small roundish compartments assumed to be ER-derived protein bodies. The molecular farming potential of the system was tested by generating doubled haploid transgenic lines engineered to synthesize the anti-HIV-1 monoclonal antibody 2G12 with up to 160 μg recombinant protein per g grain. The recombinant protein was deposited at the periphery of protein bodies in the form of a mixture of various N-glycans (notably those lacking terminal N-acetylglucosamine residues, consistent with their vacuolar localization. Inspection of protein-A purified antibodies using surface plasmon resonance spectroscopy showed that their equilibrium and kinetic rate constants were comparable to those associated with recombinant 2G12 synthesized in Chinese hamster ovary cells.

  19. Gene expression in the developing aleurone and starchy endosperm of wheat.

    Science.gov (United States)

    Gillies, Susan A; Futardo, Agnelo; Henry, Robert J

    2012-08-01

    Wheat is a critical food source globally. Food security is an increasing concern; current production levels are not expected to keep pace with global demand. New technologies have provided a vast array of wheat genetic data; however, best use of this data requires placing it within a framework in which the various genes, pathways and interactions can be examined. Here we present the first systematic comparison of the global transcriptomes of the aleurone and starchy endosperm of the developing wheat seed (Triticum aestivum), at time points critical to the development of the aleurone layer; 6-, 9- and 14-day post-anthesis. Illumina sequencing gave 25-55 million sequence reads per tissue, of the trimmed reads, 70%-81% mapped to reference expressed sequence transcripts. Transcript abundance was analysed by performing RNA-Seq normalization to generate reads per kilobase of exon model per million mapped reads values, and these were used in comparative analyses between the tissues at each time point using Kal's Z-test. This identified 9414-13 202 highly differentially expressed transcripts that were categorized on the basis of tissue and time point expression and functionally analysed revealing two very distinct tissues. The results demonstrate the fundamental biological reprogramming of the two major biologically and economically significant tissues of the wheat seed over this time course. Understanding these changes in gene expression profiles is essential to mining the potential these tissues hold for human nutrition and contributing to the systems biology of this important crop plant.

  20. The role of maize root size in phosphorus uptake and productivity of maize/faba bean and maize/wheat intercropping systems.

    Science.gov (United States)

    Zhang, Yikai; Chen, Fanjun; Li, Long; Chen, Yanhua; Liu, Bingran; Zhou, Yuling; Yuan, Lixing; Zhang, Fusuo; Mi, Guohua

    2012-11-01

    Interspecific root/rhizosphere interactions affect phosphorus (P) uptake and the productivity of maize/faba bean and maize/wheat intercropping systems. The aim of these experiments was to determine whether manipulation of maize root growth could improve the productivity of the two intercropping systems. Two near isogenic maize hybrids (the larger-rooted T149 and smaller-rooted T222) were intercropped with faba bean and wheat, under conditions of high- and low-P availability. The larger-rooted T149 showed greater competitive ability than the smaller-rooted T222 in both maize/faba bean and maize/wheat intercropping systems. The higher competitive ability of T149 improved the productivity of the maize/faba bean intercropping system in P-sufficient conditions. In maize/wheat intercropping systems, root growth, shoot biomass, and P uptake of maize were inhibited by wheat, regardless of the P-supply. Compared with T222, the larger-rooted T149 suffered less in the intercropping systems. The total biomass of the maize/wheat intercropping system was higher for wheat/T149 than for wheat/T222 under low-P conditions. These data suggested that genetic improvement of maize root size could enhance maize growth and its ability to compete for P resources in maize/faba bean and maize/wheat intercropping systems. In addition, depending on the P availability, larger maize roots could increase the productivity of intercropping systems.

  1. The influence of drought on the occurrence of aflatoxins in maize

    Directory of Open Access Journals (Sweden)

    Kos Jovana J.

    2013-01-01

    Full Text Available In this study, a total of 78 maize samples harvested during September and October 2012 in Vojvodina were analyzed. Presence of aflatoxins (AFs was deter­mined by enzyme-linked immunosorbent assay (ELISA method. Among the 78 analyzed maize samples, even 44 (56.4% samples were contaminated with AFs. Concentration interval between 1-10 μg/kg, 10-50 μg/kg and 50-80 μg/kg were found in 23.1%, 17.9% and 15.4% of analyzed maize samples, respectively. It was supposed that prolonged drought during spring and summer of 2012 had a great influence on high contamination frequency and concentration of AFs. [Projekat Ministarstva nauke Republike Srbije, br. III 46001

  2. The iojap gene in maize

    Energy Technology Data Exchange (ETDEWEB)

    Martienssen, Robert

    2001-12-01

    The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.

  3. Genome-Wide Analysis of Alternative Splicing during Development and Drought Stress in Maize.

    Science.gov (United States)

    Thatcher, Shawn R; Danilevskaya, Olga N; Meng, Xin; Beatty, Mary; Zastrow-Hayes, Gina; Harris, Charlotte; Van Allen, Brandon; Habben, Jeffrey; Li, Bailin

    2016-01-01

    Alternative splicing plays a crucial role in plant development as well as stress responses. Although alternative splicing has been studied during development and in response to stress, the interplay between these two factors remains an open question. To assess the effects of drought stress on developmentally regulated splicing in maize (Zea mays), 94 RNA-seq libraries from ear, tassel, and leaf of the B73 public inbred line were constructed at four developmental stages under both well-watered and drought conditions. This analysis was supplemented with a publicly available series of 53 libraries from developing seed, embryo, and endosperm. More than 48,000 novel isoforms, often with stage- or condition-specific expression, were uncovered, suggesting that developmentally regulated alternative splicing occurs in thousands of genes. Drought induced large developmental splicing changes in leaf and ear but relatively few in tassel. Most developmental stage-specific splicing changes affected by drought were tissue dependent, whereas stage-independent changes frequently overlapped between leaf and ear. A linear relationship was found between gene expression changes in splicing factors and alternative spicing of other genes during development. Collectively, these results demonstrate that alternative splicing is strongly associated with tissue type, developmental stage, and stress condition.

  4. Genome-Wide Analysis of Alternative Splicing during Development and Drought Stress in Maize1[OPEN

    Science.gov (United States)

    Thatcher, Shawn R.; Meng, Xin; Beatty, Mary; Zastrow-Hayes, Gina; Harris, Charlotte; Habben, Jeffrey; Li, Bailin

    2016-01-01

    Alternative splicing plays a crucial role in plant development as well as stress responses. Although alternative splicing has been studied during development and in response to stress, the interplay between these two factors remains an open question. To assess the effects of drought stress on developmentally regulated splicing in maize (Zea mays), 94 RNA-seq libraries from ear, tassel, and leaf of the B73 public inbred line were constructed at four developmental stages under both well-watered and drought conditions. This analysis was supplemented with a publicly available series of 53 libraries from developing seed, embryo, and endosperm. More than 48,000 novel isoforms, often with stage- or condition-specific expression, were uncovered, suggesting that developmentally regulated alternative splicing occurs in thousands of genes. Drought induced large developmental splicing changes in leaf and ear but relatively few in tassel. Most developmental stage-specific splicing changes affected by drought were tissue dependent, whereas stage-independent changes frequently overlapped between leaf and ear. A linear relationship was found between gene expression changes in splicing factors and alternative spicing of other genes during development. Collectively, these results demonstrate that alternative splicing is strongly associated with tissue type, developmental stage, and stress condition. PMID:26582726

  5. Genetic modification of low phytic acid 1-1 maize to enhance iron content and bioavailability.

    Science.gov (United States)

    Aluru, Maneesha R; Rodermel, Steve R; Reddy, Manju B

    2011-12-28

    High phytate content in staple food crops is a major barrier to successful iron biofortification. We have exploited the low phytic acid 1-1 (lpa1-1) mutant of maize to generate transgenic plants with up-to 70 μg/g seed iron through the endosperm-specific overexpression of soybean ferritin, resulting in more than 2-fold improvement in iron bioavailability. The levels of bioavailable seed iron achieved in this study greatly exceed any achieved thus far and closely approach values estimated to have a nutritional impact on target populations. Gene expression studies reveal a large induction of the YS1 transporter in leaves and severe repression of an iron acquisition gene DMAS1 in roots, suggesting significant alterations in the iron homeostatic mechanisms in transgenic lpa1-1. Furthermore, preliminary tests show that the high-iron lpa1-1 seeds have higher germination rates and seedling vigor when compared to those of the nontransgenic seeds, which may help improve their value to plant breeders.

  6. Depth Profiles in Maize ( Zea mays L.) Seeds Studied by Photoacoustic Spectroscopy

    Science.gov (United States)

    Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Zepeda-Bautista, R.

    2015-06-01

    Photoacoustic spectroscopy (PAS) has been used to analyze agricultural seeds and can be applied to the study of seed depth profiles of these complex samples composed of different structures. The sample depth profile can be obtained through the photoacoustic (PA) signal, amplitude, and phase at different light modulation frequencies. The PA signal phase is more sensitive to changes of thermal properties in layered samples than the PA signal amplitude. Hence, the PA signal phase can also be used to characterize layers at different depths. Thus, the objective of the present study was to obtain the optical absorption spectra of maize seeds ( Zea mays L.) by means of PAS at different light modulation frequencies (17 Hz, 30 Hz, and 50 Hz) and comparing these spectra with the ones obtained from the phase-resolved method in order to separate the optical absorption spectra of seed pericarp and endosperm. The results suggest the possibility of using the phase-resolved method to obtain optical absorption spectra of different seed structures, at different depths, without damaging the seed. Thus, PAS could be a nondestructive method for characterization of agricultural seeds and thus improve quality control in the food industry.

  7. Identification and Characterization of Maize salmon silks Genes Involved in Insecticidal Maysin Biosynthesis[OPEN

    Science.gov (United States)

    Falcone-Ferreyra, María Lorena; Rodríguez, Eduardo; Engelmeier, Jacob; Grotewold, Erich

    2016-01-01

    The century-old maize (Zea mays) salmon silks mutation has been linked to the absence of maysin. Maysin is a C-glycosyl flavone that, when present in silks, confers natural resistance to the maize earworm (Helicoverpa zea), which is one of the most damaging pests of maize in America. Previous genetic analyses predicted Pericarp Color1 (P1; R2R3-MYB transcription factor) to be epistatic to the sm mutation. Subsequent studies identified two loci as being capable of conferring salmon silks phenotypes, salmon silks1 (sm1) and sm2. Benefitting from available sm1 and sm2 mapping information and from knowledge of the genes regulated by P1, we describe here the molecular identification of the Sm1 and Sm2 gene products. Sm2 encodes a rhamnosyl transferase (UGT91L1) that uses isoorientin and UDP-rhamnose as substrates and converts them to rhamnosylisoorientin. Sm1 encodes a multidomain UDP-rhamnose synthase (RHS1) that converts UDP-glucose into UDP-l-rhamnose. Here, we demonstrate that RHS1 shows unexpected substrate plasticity in converting the glucose moiety in rhamnosylisoorientin to 4-keto-6-deoxy glucose, resulting in maysin. Both Sm1 and Sm2 are direct targets of P1, as demonstrated by chromatin immunoprecipitation experiments. The molecular characterization of Sm1 and Sm2 described here completes the maysin biosynthetic pathway, providing powerful tools for engineering tolerance to maize earworm in maize and other plants. PMID:27221383

  8. Cytogenetic Mapping of Disease Resistance Genes and Analysis of Their Distribution Features on Chromosomes in Maize

    Institute of Scientific and Technical Information of China (English)

    LiLi-jia; SongYun-chun

    2003-01-01

    Cytogenetic maps of four clusters of disease resistance genes were generated by ISH of the two RFLP markers tightly linked to and flanking each of maize resistance genes and the cloned resistance genes from other plant species onto maize chromosomes, combining with data published before. These genes include Helminthosporium turcium Pass resistance genes Htl, Htnl and Ht2, Helminthosporium maydis Nisik resistance genes Rhml and Rhm2,maize dwarf mosaic virus resistance gene Mdml, wheat streak mosaic virus resistance gene Wsml, Helminthosporium carbonum ULLstrup resistance gene Hml and the cloned Xanthomonas oryzae pv. Oryzae resistance gene Xa21 of rice, Cladosporium fulvum resistance genes Cf-9 and Cf-2. 1 of tomato, and Pseudomonas syringae resistance gene RPS2 of Arabidopsis. Most of the tested disease resistance genes located on the four chromosomes, i. e. , chromosomesl, 3, 6 and 8, and they closely distributed at the interstitial regions of these chromosomal long arms with percentage distances ranging 31.44(±3.72)-72.40(±3. 25) except for genes Rhml, Rhm2, Mdml and Wsml which mapped on the satellites of the short arms of chromosome6. It showed that the tested RFLP markers and genes were duplicated or triplicated in maize genome. Homology and conservation of disease resistance genes among species, and relationship between distribution features and functions of the genes were discussed. The results provide important scientific basis for deeply understanding structure and function of disease resistance genes and breeding in maize.

  9. Effects of Selenium on Maize Ovary Development at Pollination Stage Under Water Deficits

    Institute of Scientific and Technical Information of China (English)

    SHEN Qiang-yun; Marja Turakainen; Mervi Seppanen; Pirjo M(a)kel(a)

    2008-01-01

    Maize ovary development is linked to kernel formation. Soil water deficit results in ovary abortion because of low water potential (ψw) resulting in inhibition of photosynthesis from anthesis to silking stage. Thus, drought is a key factor causing yield losses in maize, especially near the time of pollination. Earlier studies have indicated that selenium (Se) maintains antioxidative defence systems and enhances sugar and starch accumulation. The effects of Se on maize ovary development were studied in drought stress conditions. Maize ovary development was studied through observations on starch, membrane integrity, fresh weight and dry weight in drought-treated or unstressed glasshouse-grown plants, and crop yield, yield structure, leaf, stem and ear biomass accumulation were also analyzed. Results indicated that Se increased the stress tolerance of the crop, even though ovary abortion was not eliminated by Se treatments under low ψw. Under well-watered control conditions, Se had also negative effects. When the first ear was not succesfully pollinated or the ovaries aborted, the plants developed more ears. Even though these later formed ears did not produce kernels, they significantly increased the dry weight of the plants under water deficit. It could be concluded that The optimal concentration for maize of Se applied through roots is about 0.01 mg kg-1 (supplied as Na2SeO4) soil or less.

  10. Use of tropical maize for bioethanol production

    Science.gov (United States)

    Tropical maize is an alternative energy crop being considered as a feedstock for bioethanol production in the North Central and Midwest United States. Tropical maize is advantageous because it produces large amounts of soluble sugars in its stalks, creates a large amount of biomass, and requires lo...

  11. Towards the improvement of maize in Nigeria

    NARCIS (Netherlands)

    Eijnatten, van C.L.M.

    1965-01-01

    Approximately 600,000 tons of maize were produced annually in Nigeria. Maize was the main grain crop in southern Nigeria and its production in the middle belt was rapidly increasing. Most of the crop was eaten as dry grain, a little before maturity. A preference was recorded for floury varieties of

  12. ZP maize hybrids as silage raw material

    Directory of Open Access Journals (Sweden)

    Terzić Dušanka

    2012-01-01

    Full Text Available Due to its yields, biomass quality and biomass suitability for ensiling, diversity of use in feedstuff, maize is one of the most important forage plants. In comparison with other forage plants, the production of silage maize results in the greatest accumulation of solar energy per area unit. The positive correlation between a high density of net energy and the concentration of net energy as well as between digestibility of organic matter and the concentration of net energy is achieved in the produced biomass of maize plant. The yield of silage maize in dependence on the genetic potential of yield and agroecological conditions of the production ranges from 12 to 25 tonnes of the total dry matter per hectare at physiological maturity for ensiling with the dry matter content of 35-42%. This study presents results obtained in the long-term scientific and research programme on the improvement of ZP maize hybrids utilisation carried out in the Department of Technological Research at the Maize Research Institute Zemun Polje. The overall presentation of biomass quality parameters of six ZP maize hybrids (ZP 158, ZP 173/8, ZP 377, ZP 440, ZP 555 and ZP 679 of different genetic backgrounds intended for silage production is given in this study. Besides, interrelationships among these factors as well as their effects on maize biomass digestibility were established.

  13. Exploring maize-legume intercropping systems in Southwest Mexico

    NARCIS (Netherlands)

    Flores-Sanchez, D.; Pastor, A.V.; Lantinga, E.A.; Rossing, W.A.H.; Kropff, M.J.

    2013-01-01

    Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus

  14. Scandinavian links

    DEFF Research Database (Denmark)

    Matthiessen, Christian Wichmann; Knowles, Richard D.

    2014-01-01

    centres, one joins more thinly populated regions, and the last one links peripheral areas. Two of them (The Great Belt Link and the Oresund Link) have been constructed and are in full operation. The third (the Fehmarnbelt Link) has been decided 2008 on bilateral government level. The three links...

  15. ADVANCES IN TRANSGENIC MAIZE FOR QUALITY IMPROVEMENT

    Directory of Open Access Journals (Sweden)

    M.Rajendar Reddy

    2015-12-01

    Full Text Available Maize (Zea mays is a major food and animal feed worldwide and occupies a relevant place in the world economy and trade as an industrial grain crop. Currently more than 70% of maize production is used for food and feed; therefore, knowledge of genes involved in grain structure and chemical is important for improving the nutritional and food-making properties of maize. It is a good source of carbohydrates, fats, proteins, vitamins and minerals but deficient in two essential amino acids, Viz., lysine and tryptophan. To overcome this problem and to improve the above quality characters the maize breeders have followed different strategies like opaque 2, QPM and development of transgenic maize with improved quality characters. Finally we can conclude that the conventional breeding techniques and now plant biotechnology are helping meet the growing demand for food production, nutrition security while preserving our environment for future generations

  16. PEMANFAATAN FRAKSI KAYA ASAM LAURAT HASIL HIDROLISIS DARI ENDOSPERM KELAPA MENGGUNAKAN LIPASE ENDOGENEUS SEBAGAI PENGAWET SUSU KEDELAI KEMASAN (Utilization of High Lauric Fraction that Produced from Coconut Endosperm Using Lipase Endogenous as Preservation of Soybean Milk Packaging

    Directory of Open Access Journals (Sweden)

    Moh. Su'i

    2016-10-01

    Full Text Available Results of previous studies show that the high lauric fraction isolated from coconut endosperm is able to inhibit pathogenic and non-pathogenic bacteria. This research aims to study the addition of high lauric fraction that hydrolysed of coconut endosperm of the storability of soy milk packaging. High lauric fraction isolated from coconut milk, then the fraction analized of the fatty acid composition with gas chromatography (GC and then used as a preservative soy milk. The fraction is added to the soy milk with concentrations of 0, 10, 15 and 20%, then stored for 3 days. Every day is observed until soy milk damaged. The results showed that the fraction isolated from coconut milk contains 50.45% lauric acid, 17.52% myristic acid, 7.02% palmitic acid, 6.46% capric acid, 5.52% caprylic acid, 5.12% linoleic acid, 1.89% oleic acid, and 0.11% caproic acid. The addition of lauric acid-rich fraction of 20% were able to preserve soy milk for 2 days with a total microbe 1.00 x 104 cfu/ml, free fatty acids 0.12 m mol/ml, pH 5.05 and a balanced aroma 4 (nice. Keywords: Coconut, lauric acid, soy milk, storage ABSTRAK Hasil penelitian sebelumnya menunjukkan bahwa fraksi kaya asam laurat hasil isolasi dari endosperm kelapa mampu menghambat bakteri patogen dan non patogen. Penelitian ini bertujuan mempelajari penambahan fraksi kaya asam laurat hasil hidrolisis dari endosperm kelapa terhadap daya simpan susu kedelai kemasan. Fraksi yang kaya asam laurat diisolasi dari santan kelapa kemudian fraksi tersebut diuji komposisi asam lemaknya menggunakan chromatografi gas (GC dan selanjutnya digunakan sebagai bahan pengawet susu kedelai. Fraksi kaya asam laurat ditambahkan ke dalam susu kedelai dengan konsentrasi 0, 10, 15 dan 20%, kemudian disimpan selama 3 hari. Setiap hari dilakukan pengamatan hingga susu mengalami kerusakan. Hasil penelitian menunjukkan bahwa fraksi hasil isolasi dari santan kelapa mengandung asam laurat 50,45%, asam miristat 17,52%, asam palmitat

  17. The link in Linking

    Science.gov (United States)

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  18. New strategy for the determination of gliadins in maize- or rice-based foods matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: fractionation of gliadins from maize or rice prolamins by acidic treatment.

    Science.gov (United States)

    Hernando, Alberto; Valdes, Israel; Méndez, Enrique

    2003-08-01

    A procedure for determining small quantities of gliadins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) in gluten-free foods containing relatively large amounts of prolamin proteins from maize or rice is described. We report for the first time that gliadins, the ethanol-soluble wheat prolamin fraction, can be quantitatively solubilized in 1.0 M acetic acid, while the corresponding ethanol-soluble maize or rice prolamin fraction remains insoluble in acetic acid. We describe a methodology for the detection of gliadins in maize and rice foods based on a two-step procedure of extraction (60% aqueous ethanol followed by 1 M acetic acid). Subsequent MALDI-TOFMS analysis of the resulting acidic extract from these gluten-free foods clearly confirms the presence of a typical mass pattern corresponding to gliadin components, ranging from 30 to 45 kDa. Depending on the percentages of maize or rice flours employed in the elaboration of these foods, the combined procedure enables levels of gliadins from 100 to 400 ppm to be detected. The efficiency of this combined procedure corroborates enzyme-linked immunosorbent assay data for a large number of maize/rice gluten-free foods by means of direct visualization of the characteristic gliadin mass pattern in maize or rice foods.

  19. Recombinant human proinsulin from transgenic corn endosperm: solvent screening and extraction studies

    Directory of Open Access Journals (Sweden)

    C. S. Farinas

    2007-09-01

    Full Text Available Recombinant pharmaceutical proteins are being produced in different systems such as bacteria and mammalian cell cultures. The use of transgenic plants as bioreactors has recently arisen as an alternative system offering many practical and economic advantages. However, finding an optimum strategy for the downstream processing (DSP of recombinant proteins from plants still remains a challenge. In this work, we studied the extraction of recombinant human proinsulin (rhProinsulin produced in the endosperm of transgenic corn seeds. An efficient extraction solvent was selected and the effects of temperature, solvent-to-solid ratio, time, and impeller rotational speed on the extraction were evaluated using an experimental design. After an extraction kinetics study, temperature was further evaluated to maximize rhProinsulin concentration in the extracts and to minimize the native corn components carbohydrates, phenolic compounds, and proteins. A high efficiency condition for extracting rhProinsulin with the selected solvent - 50 mM sodium bicarbonate buffer pH 10.0 and 5 mM DTT - was an extraction time of 2 h at a solvent-to-solid ratio of 10:1 and 25º C. The maximum rhProinsulin concentration in the extracts at that condition was 18.87 mg l-1 or 0.42% of the total soluble protein. These values are within the range in which the production of pharmaceutical proteins in plants can be competitive with other expression systems. The results presented provide information for the development of an additional production platform for the hormone insulin.

  20. Microscopic Structures of Endosperms Before and After Gelatinization in Rice Varieties with Varied Grain Quality

    Institute of Scientific and Technical Information of China (English)

    YANG Ze-min; WANG Wei-jin; LAN Sheng-yin; XU Zhen-xiu; ZHOU Zhu-qing; WANG Meng

    2003-01-01

    The microscopic structures of the endosperm of indica rice varieties with different quality be-fore and after gelatinization were observed using scanning electron microscope. The results showed that the de-gree of gelatinization varied in different parts of the grain and in different varieties under the same experimen-tal conditions. The gelatinization of dorsal side was the most complete. Its cells were decomposed totally intopuff-like or flocculent materials. The ventral side gelatinized less thoroughly, appearing agglomerate and somecell frames were still visible. The middle part gelatinized most incompletely and the cells were still integrated.Evident differences in gelatinization were observed among different varieties, the dorsal, ventral and middleparts of high quality varieties gelatinized more thoroughly than those of the corresponding parts of low qualityvarieties respectively. An obvious concavity often appeared in the middle of the cross-section of the low qualitygrains while the cross-section of high quality grains was normally flat. The same phenomenon was noted whencomparing the early maturing indica rice and the late maturing indica rice. Varietal difference of gelatiniza-tion in dorsal sides was not as distinct as in middle parts and ventral sides. The difference among dorsal side,middle part and ventral side in gelatinization was greater in low quality grains than that of high quality grains.In addition, a lot of ruptured cells were observed in the cross-section of high quality rice, while few of themcould be found in the low quality rice. Apparently, the number of ruptured cells is positively correlated withrice quality. Quality of rice grain also has positive correlation with the rate of water absorption and extension. Highrates of water absorption and extension lead to better gelatinization of rice grain, and hence indicate good quality.

  1. Early stages of spindle formation and independence of chromosome and microtubule cycles in Haemanthus endosperm.

    Science.gov (United States)

    Smirnova, E A; Bajer, A S

    1998-01-01

    We analyzed transformation of the interphase microtubular cytoskeleton into the prophase spindle and followed the pattern of spindle axis determination. Microtubules in endosperm of the higher plant Haemanthus (Scadoxus) were stained by the immunogold and immunogold silver-enhanced methods. Basic structural units involved in spindle morphogenesis were "microtubule converging centers." We emphasized the importance of relative independence of chromosomal and microtubular cycles, and the influence of these cycles on the progress of mitosis. Cells with moderately desynchronized cycles were functional, but extreme desynchronization led to aberrant mitosis. There were three distinct phases of spindle development. The first one comprised interphase and early to mid-prophase. During this phase, the interphase microtubule meshwork radiating from the nuclear surface into the cytoplasm rearranged and formed a dense microtubule cage around the nucleus. The second phase comprised mid to late prophase, and resulted in the formation of normal (bipolar) or transitory aberrant (apolar or multipolar) prophase spindles. The third phase comprised late prophase with prometaphase. The onset of prometaphase was accompanied by a rapid association of microtubule converging centers with kinetochores. In this stage aberrant spindles transformed invariably into bipolar ones. Lateral association of a few bipolar kinetochore fibers at early prometaphase established the core of the bipolar spindle and its alignment. We concluded that (1) spindle formation is a largely independent microtubular process modified by the chromosomal/kinetochore cycle; and (2) the initial polarity of the spindle is established by microtubule converging centers, which are a functional substitute of the centrosome/MTOC. We believe that the dynamics of microtubule converging centers is an expression of microtubule self-organization driven by motor proteins as proposed by Mitchison [1992: Philos. Trans. R. Soc. Lond. B

  2. Isolation and characterization of wheat bran starch and endosperm starch of selected soft wheats grown in Michigan and comparison of their physicochemical properties.

    Science.gov (United States)

    Liu, Ya; Ng, Perry K W

    2015-06-01

    Three soft wheat varieties with relatively high crop yields and different levels of milling softness equivalence were studied to characterize bran starch properties compared with those of endosperm starch from the same wheat sample. Bran starch had more short chains than had endosperm starch, and was found to have a higher percentage of B-type granules, higher amylose content, higher crystallinity, broader gelatinization temperature range, higher enthalpy of gelatinization, lower retrogradation degree, and lower pasting peak and setback viscosities than had the counterpart endosperm starch. Bran starch of variety Aubrey had the highest crystallinity (21.75%) and gelatinization temperature (62.9°C), while bran starch of variety D8006 had the highest percentage of B-type granules and lowest retrogradation degree (21.7%). Results of this study provide a foundation for better utilization of bran starch during whole grain food processing.

  3. Novas observações citológicas no endosperma de café Cytological observations on coffee endosperm

    Directory of Open Access Journals (Sweden)

    Dixier M. Medina

    1965-01-01

    Full Text Available Contagens de cromossomos foram efetuadas em endosperma de algumas espécies de Coffea, empregando-se a técnica da orceína acética, já referida em trabalho anterior. Os resultados encontrados para C. arabica (variedades typica, semperflorens, 2n = 44, e plantas monossômicas, 2n = 43 ; C. canephora, 2n = 22, C. dewevrei, 2n = 22, C. eugenioides x C. kapakata, 2n = 22 e C. eugenioides duplicado, 2n = 44, são discutidos em cada caso. Em todo o material estudado foi constatada a endomitose. O endosperma é, no início, um tecido de constituição 3x, transformando-se depois num tecido quimérico com células polissomáticas de diferentes graus. As numerosas figuras conseguidas, que permitiram contagens ou microfotografias, confirmam que, no cafeeiro, o endosperma é um material favorável para pesquisas citológicas.Chromosome countings have been rnade on lhe endosperm of Coffea using the same technique of acetic oreein already referred to in previous work of the author. Endosperm from the varieties typica and semperflorens (2n = 44 and monosomic plants (2n = 43 of C. arabica as well as of other species as C. canephora (2n = 22, C. dewevrei (2n = 22, C. eugenioides x C. kapakata (2n = 22 and duplicated C. eugenioides (2n = 44 were studied. Gametic number of chromosomes are discussed leading in some cases to the conclusion that gametes with missing chromosomes and gametes with supernumerary chromosomes were functional. Endomitosis was observed in all material studied. Endosperm tissue is constituted, therefore, by polysomatic cells (6x, 12x in addition to the monosomatic ones (3x initially formed through fertilization. The possible relation of endomitosis and embryo development is also discussed. The great number of photomicrographies obtained indicates once more that coffee endosperm is a favourable material for cytological investigations.

  4. INTEGRATED WEED CONTROL IN MAIZE.

    Science.gov (United States)

    Latré, J; Dewitte, K; Derycke, V; De Roo, B; Haesaert, G

    2015-01-01

    Integrated pest management has been implemented as a general practice by EU legislation. As weed control actually is the most important crop protection measure in maize for Western Europe, the new legislation will have its impact. The question is of course which systems can be successfully implemented in practice with respect to labour efficiency and economical parameters. During 3 successive growing seasons (2007, 2008, 2009) weed control in maize was evaluated, the main focus was put on different techniques of integrated weed control and was compared with chemical weed control. Additionally, during 4 successive growing seasons (2011, 2012, 2013 and 2014) two objects based on integrated weed control and two objects based on mechanical weed control were compared to about twenty different objects of conventional chemical weed control. One of the objects based on mechanical weed control consisted of treatment with the flex-tine harrow before and after emergence in combination with chemical weed control at a reduced rate in 3-4 leave stage. The second one consisted of broadcast mechanical treatments before and after emergence followed by a final in-row application of herbicides and an inter-row cultivation at 6-7(8) leave stage. All trials were conducted on the Experimental farm of Bottelare HoGent-UGent on a sandy loam soil. Maize was growing in 1/3 crop rotation. The effect on weed growth as well as the economic impact of the different applications was evaluated. Combining chemical and mechanical weed control is a possible option in conventional farming but the disadvantages must be taken into account. A better planned weed control based on the real present weed-population in combination with a carefully thought-out choice of herbicides should also be considered as an IPM--approach.

  5. Identification, Characterization, and Functional Validation of Drought-responsive MicroRNAs in Subtropical Maize Inbreds

    Directory of Open Access Journals (Sweden)

    Jayaraman Aravind

    2017-06-01

    Full Text Available MicroRNA-mediated gene regulation plays a crucial role in controlling drought tolerance. In the present investigation, 13 drought-associated miRNA families consisting of 65 members and regulating 42 unique target mRNAs were identified from drought-associated microarray expression data in maize and were subjected to structural and functional characterization. The largest number of members (14 was found in the zma-miR166 and zma-miR395 families, with several targets. However, zma-miR160, zma-miR390, zma-miR393, and zma-miR2275 each showed a single target. Twenty-three major drought-responsive cis-regulatory elements were found in the upstream regions of miRNAs. Many drought-related transcription factors, such as GAMYB, HD-Zip III, and NAC, were associated with the target mRNAs. Furthermore, two contrasting subtropical maize genotypes (tolerant: HKI-1532 and sensitive: V-372 were used to understand the miRNA-assisted regulation of target mRNA under drought stress. Approximately 35 and 31% of miRNAs were up-regulated in HKI-1532 and V-372, respectively. The up-regulation of target mRNAs was as high as 14.2% in HKI-1532 but was only 2.38% in V-372. The expression patterns of miRNA-target mRNA pairs were classified into four different types: Type I- up-regulation, Type II- down-regulation, Type III- neutral regulation, and Type IV- opposite regulation. HKI-1532 displayed 46 Type I, 13 Type II, and 23 Type III patterns, whereas V-372 had mostly Type IV interactions (151. A low level of negative regulations of miRNA associated with a higher level of mRNA activity in the tolerant genotype helped to maintain crucial biological functions such as ABA signaling, the auxin response pathway, the light-responsive pathway and endosperm expression under stress conditions, thereby leading to drought tolerance. Our study identified candidate miRNAs and mRNAs operating in important pathways under drought stress conditions, and these candidates will be useful in the

  6. Reshaping of the maize transcriptome by domestication.

    Science.gov (United States)

    Swanson-Wagner, Ruth; Briskine, Roman; Schaefer, Robert; Hufford, Matthew B; Ross-Ibarra, Jeffrey; Myers, Chad L; Tiffin, Peter; Springer, Nathan M

    2012-07-17

    Through domestication, humans have substantially altered the morphology of Zea mays ssp. parviglumis (teosinte) into the currently recognizable maize. This system serves as a model for studying adaptation, genome evolution, and the genetics and evolution of complex traits. To examine how domestication has reshaped the transcriptome of maize seedlings, we used expression profiling of 18,242 genes for 38 diverse maize genotypes and 24 teosinte genotypes. We detected evidence for more than 600 genes having significantly different expression levels in maize compared with teosinte. Moreover, more than 1,100 genes showed significantly altered coexpression profiles, reflective of substantial rewiring of the transcriptome since domestication. The genes with altered expression show a significant enrichment for genes previously identified through population genetic analyses as likely targets of selection during maize domestication and improvement; 46 genes previously identified as putative targets of selection also exhibit altered expression levels and coexpression relationships. We also identified 45 genes with altered, primarily higher, expression in inbred relative to outcrossed teosinte. These genes are enriched for functions related to biotic stress and may reflect responses to the effects of inbreeding. This study not only documents alterations in the maize transcriptome following domestication, identifying several genes that may have contributed to the evolution of maize, but highlights the complementary information that can be gained by combining gene expression with population genetic analyses.

  7. Nutrient absorbtion of weeds in maize.

    Science.gov (United States)

    Lehoczky, E; Kismányoky, A; Nagy, P; Németh, T

    2008-01-01

    Our study was carried out in Hungary at Keszthely, in 2007. The effect of different cultivation methods: no-till drill, disk tillage, conventional tillage (ploughing) and five increasing N doses were studied on the weediness. The bi-factorial trial was arranged in split plot design with four replications. Crop rotation: winter wheat-winter wheat-maize-maize. The seeding of maize was 23rd of April in 2007. The weed survey was made with Balázs-Ujvárosi coenological method on the 17th of May. In the experiment were found 21 weed species. We collected all plants of every weed species by plots. The sample area was 1 m2. Furthermore five maize plants per plot were sampled on the 22nd of May. Maize was at 3-4 leaves stage. For reason of competition studies no herbicides were applied on sampling sites. The aerial parts of weeds and maize plants were collected, and the fresh and dry matter weight was measured. We analyzed in detail, the occurrence of weed species, and the biomass production of weeds in comparison with maize. The effect of different cultivation methods markedly demonstrated the weed cover, the number of perennial and annual weeds and the number of occurring weed species.

  8. Cytotoxicity of Ustilago maydis isolated from maize

    Directory of Open Access Journals (Sweden)

    Magdalena Twarużek

    2013-03-01

    Full Text Available The main pathogen of maize are fungi of the genus Fusarium. Besides phytopathogenic Fusarium, Ustilago maydis is another fungal genus affecting maize yields, causing lesions, known as smut. The objective of the study was evaluation of the cytotoxicity of Ustilago maydis isolated from maize. Nine Ustilago maydis strains were selected to a detailed evaluation of their cytotoxicity using a 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT test. Ustilago maydis strains showed medium and high cytotoxicity compared to control. High levels of cytotoxicity of Ustilago maydis may be indicative of their toxigenic potential.

  9. Hardness methods for testing maize kernels.

    Science.gov (United States)

    Fox, Glen; Manley, Marena

    2009-07-08

    Maize is a highly important crop to many countries around the world, through the sale of the maize crop to domestic processors and subsequent production of maize products and also provides a staple food to subsistance farms in undeveloped countries. In many countries, there have been long-term research efforts to develop a suitable hardness method that could assist the maize industry in improving efficiency in processing as well as possibly providing a quality specification for maize growers, which could attract a premium. This paper focuses specifically on hardness and reviews a number of methodologies as well as important biochemical aspects of maize that contribute to maize hardness used internationally. Numerous foods are produced from maize, and hardness has been described as having an impact on food quality. However, the basis of hardness and measurement of hardness are very general and would apply to any use of maize from any country. From the published literature, it would appear that one of the simpler methods used to measure hardness is a grinding step followed by a sieving step, using multiple sieve sizes. This would allow the range in hardness within a sample as well as average particle size and/or coarse/fine ratio to be calculated. Any of these parameters could easily be used as reference values for the development of near-infrared (NIR) spectroscopy calibrations. The development of precise NIR calibrations will provide an excellent tool for breeders, handlers, and processors to deliver specific cultivars in the case of growers and bulk loads in the case of handlers, thereby ensuring the most efficient use of maize by domestic and international processors. This paper also considers previous research describing the biochemical aspects of maize that have been related to maize hardness. Both starch and protein affect hardness, with most research focusing on the storage proteins (zeins). Both the content and composition of the zein fractions affect

  10. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    OpenAIRE

    Achhami, Buddhi Bahadur; Santa Bahadur BK; Bhandari, GhanaShyam

    2015-01-01

    Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and...

  11. Heterosis of maize photosynthetic performance

    Institute of Scientific and Technical Information of China (English)

    LI Xia; DING Zaisong; LI Lianlu; WANG Meiyun; ZHAO Ming

    2007-01-01

    Four maize inbred lines with different photosyn-thetic rates and their two hybrids were used as test materials,and the diurnal variations of their photosynthesis parameters in the silking stage were measured to study the heterosis of photosynthetic performance.Results showed that net photo-synthetic rate (In),transpiration rate (Tr) and stomatal conductance (Gs) all presented an obvious single-peaked curve in a day,with the peak values occurring at 10:00-12:00,12:00,10:00-12:00 a.m.,respectively,while water use efficiency (WUE) had a"V"type variant trend,with the lowest value appearing at 12:00.The diurnal variation of Pn and Tr was correlated markedly with Gs,suggesting that Gs played an important role in regulating the diurnal variation of Pn and Tr,and Pn,Tr and Gs had a higher heterosis in the afternoon than in the morning,while the WUE was in reverse,indicating that maize hybrid had higher resistance to the high temperature and dehydration in the afternoon,which provided a new path to select varieties with a high net photosynthetic rate.

  12. Defective Kernel Mutants of Maize II. Morphological and Embryo Culture Studies.

    Science.gov (United States)

    Sheridan, W F; Neuffer, M G

    1980-08-01

    This report presents the initial results of our study of the immature kernel stage of 150 defective kernel maize mutants. They are single gene, recessive mutants that map throughout the genome, defective in both endosperm and embryo development and, for the most part, lethal (Neuffer and Sheridan 1980). All can be distinguished on immature ears, and 85% of them reveal a mutant phenotype within 11 to 17 days post-pollination. Most have immature kernels that are smaller and lighter in color than their normal counterparts. Forty of the mutants suffer from their defects early in kernel development and are blocked in embryogenesis before their primordia differentiate, or, if primordia are formed, they are unable to germinate when cultured as immature embryos or tested at maturity; a few begin embryo degeneration prior to the time that mutant kernels became visually distinguishable. The others express the associated lesion later in kernel development and form at least one leaf primordium by the time kernels are distinguishable and will germinate when cultured or tested at maturity. In most cases, on a fresh weight basis, the mutants have embryos that are more severely defective than the endosperm; their embryos usually are no more than one-half to two-thirds the size, and lag behind by one or two developmental stages. in comparison with embryos in normal kernels from the same ear. One hundred and two mutants were examined by culturing embryos on basal and enriched media; 21 simply enlarged or completely failed to grow on any of the media tested; and 81 produced shoots and roots on at least one medium. Many grew equally well on basal and enriched media; 16 grew at a faster rate on basal medium and 23 displayed a superior growth on enriched medium. Among the latter group, 10 may be auxotrophs. One of these mutants and another mutant isolated by E. H. Coe are proline-requiring mutants, allelic to pro-1. Considering their diversity of expression as evidenced by their

  13. Mode of endosperm and wholemeal arabinoxylans solubilisation during rye breadmaking: genotypic diversity in the level, substitution degree and macromolecular characteristics.

    Science.gov (United States)

    Cyran, Malgorzata R; Dynkowska, Wioletta M

    2014-02-15

    Insight into solubilisation mechanisms of rye arabinoxylans during breadmaking is important for understanding the biochemical processes that affect bread attributes. Purified ethanol precipitated water-extractable arabinoxylans (WE-AX) and residual unextractable counterparts (WU-AX) were isolated from rye flours and resulting breads. While the endosperm flours had lower endoxylanase activities and higher arabinose-to-xylose ratios of WU-AX than those of corresponding wholemeals, there were not any significant differences between them in the mean amounts of WU-AX hydrolysed during breadmaking. Nevertheless, they were highly affected by rye cultivar used for breadmaking. On average, 42% and 36% of WU-AX were recovered in bread WE-AX fraction, causing its 11% and 8% increase, respectively for endosperm and wholemeal breads. Bread WE-AX, however, had lower molecular weights than those of starting flours, implying chains depolymerisation. Degree of AX solubilisation depends mainly on rye genotype used, determining combined effect of enzymatic and acid hydrolyses, associations and fine structure of AX.

  14. Analysis of grain characters in temperate grasses reveals distinctive patterns of endosperm organization associated with grain shape

    Science.gov (United States)

    Drea, Sinéad

    2012-01-01

    Members of the core pooids represent the most important crops in temperate zones including wheat, barley, and oats. Their importance as crops is largely due to the grain, particularly the storage capabilities of the endosperm. In this study, a comprehensive survey of grain morphology and endosperm organization in representatives of wild and cultivated species throughout the core pooids was performed. As sister to the core pooid tribes Poeae, Aveneae, Triticeae, and Bromeae within the Pooideae subfamily, Brachypodium provides a taxonomically relevant reference point. Using macroscopic, histological, and molecular analyses distinct patterns of grain tissue organization in these species, focusing on the peripheral and modified aleurone, are described. The results indicate that aleurone organization is correlated with conventional grain quality characters such as grain shape and starch content. In addition to morphological and organizational variation, expression patterns of candidate gene markers underpinning this variation were examined. Features commonly associated with grains are largely defined by analyses on lineages within the Triticeae and knowledge of grain structure may be skewed as a result of the focus on wheat and barley. Specifically, the data suggest that the modified aleurone is largely restricted to species in the Triticeae tribe. PMID:23081982

  15. Thioredoxin reduction alters the solubility of proteins of wheat starchy endosperm: an early event in cereal germination.

    Science.gov (United States)

    Wong, Joshua H; Cai, Nick; Tanaka, Charlene K; Vensel, William H; Hurkman, William J; Buchanan, Bob B

    2004-04-01

    A KCl-soluble, albumin/globulin fraction of wheat (Triticum aestivum L.) starchy endosperm was further separated into a methanol-insoluble fraction that contained metabolic proteins and a methanol-soluble fraction that contained "chloroform-methanol" or CM-like proteins. Reduction of the disulfide bonds of the CM proteins with thioredoxin or dithiothreitol altered their properties so that, like the metabolic proteins, they were insoluble in methanol. Glutathione had little effect, indicating dithiol specificity. Proteomic analysis of the CM protein fraction revealed the presence of isoforms of low molecular weight disulfide proteins (alpha-amylase, alpha-amylase/trypsin and WCI proteinase inhibitors, lipid transfer proteins, gamma-thionins), stress enzymes (Cu-Zn superoxide dismutase and peroxidase), storage proteins (alpha-, gamma- and omega-gliadins, low molecular weight glutenin subunits and globulins of the avenin N9 type), and a component of protein degradation (polyubiquitin). These findings support the view that, in addition to modifying activity and increasing protease sensitivity, reduction by thioredoxin alters protein solubility, thereby promoting processes of the grain starchy endosperm, notably the mobilization of reserves during germination and seedling development.

  16. PvPGIP2 Accumulation in Specific Floral Tissues But Not in the Endosperm Limits Fusarium graminearum Infection in Wheat.

    Science.gov (United States)

    Tundo, Silvio; Janni, Michela; Moscetti, Ilaria; Mandalà, Giulia; Savatin, Daniel; Blechl, Ann; Favaron, Francesco; D'Ovidio, Renato

    2016-10-01

    Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most destructive fungal diseases of wheat worldwide. The pathogen infects the spike at flowering time and causes severe yield losses, deterioration of grain quality, and accumulation of mycotoxins. The understanding of the precise means of pathogen entry and colonization of floral tissue is crucial to providing effective protection against FHB. Polygalacturonase (PG) inhibiting proteins (PGIPs) are cell-wall proteins that inhibit the activity of PGs, a class of pectin-depolymerizing enzymes secreted by microbial pathogens, including Fusarium spp. The constitutive expression of a bean PGIP (PvPGIP2) limits FHB symptoms and reduces mycotoxin accumulation in wheat grain. To better understand which spike tissues play major roles in limiting F. graminearum infection, we explored the use of PvPGIP2 to defend specific spike tissues. We show here that the simultaneous expression of PvPGIP2 in lemma, palea, rachis, and anthers reduced FHB symptoms caused by F. graminearum compared with symptoms in infected nontransgenic plants. However, the expression of PvPGIP2 only in the endosperm did not affect FHB symptom development, indicating that once the pathogen has reached the endosperm, inhibition of the pathogen's PG activity is not effective in preventing its further spread.

  17. Minus end-directed kinesin-like motor protein, Kcbp, localizes to anaphase spindle poles in Haemanthus endosperm.

    Science.gov (United States)

    Smirnova, E A; Reddy, A S; Bowser, J; Bajer, A S

    1998-01-01

    Microtubule-based motor proteins assemble and reorganize acentrosomal mitotic and meiotic spindles in animal cells. The functions of motor proteins in acentrosomal plant spindles are unknown. The cellulosic cell wall and relative small size of most plant cells precludes accurate detection of the spatial distribution of motors in mitosis. Large cell size and absence of a cellulosic cell wall in Haemanthus endosperm make these cells ideally suited for studies of the spatial distribution of motor proteins during cell division. Immunolocalization of a kinesin-like calmodulin-binding protein (KCBP) in Haemanthus endosperm revealed its mitotic distribution. KCBP appears first in association with the prophase spindle. Highly concentrated within the cores of individual kinetochore fibers, KCBP decorates microtubules of kinetochore-fibers through metaphase. By mid-anaphase (when a barrel-shaped spindle becomes convergent), the protein redistributes and accumulates at the spindle polar regions. In telophase, KCBP relocates toward the phragmoplast and cell plate. These data suggest a role for KCBP in anaphase spindle microtubule convergence, which assures coherence of kinetochore-fibers within each sister chromosome group. Increasing coherence of kinetochore-fibers prevents splitting within each sister chromosome group and formation of multinucleated cells.

  18. Proteomic Analysis Reveals Different Involvement of Embryo and Endosperm Proteins during Aging of Yliangyou 2 Hybrid Rice Seeds

    Science.gov (United States)

    Zhang, Ying-Xue; Xu, Heng-Heng; Liu, Shu-Jun; Li, Ni; Wang, Wei-Qing; Møller, Ian M.; Song, Song-Quan

    2016-01-01

    Seed aging is a process that results in a delayed germination, a decreased germination percentage, and finally a total loss of seed viability. However, the mechanism of seed aging is poorly understood. In the present study, Yliangyou 2 hybrid rice (Oryza sativa L.) seeds were artificially aged at 100% relative humidity and 40°C, and the effect of artificial aging on germination, germination time course and the change in protein profiles of embryo and endosperm was studied to understand the molecular mechanism behind seed aging. With an increasing duration of artificial aging, the germination percentage and germination rate of hybrid rice seeds decreased. By comparing the protein profiles from the seeds aged for 0, 10 and 25 days, a total of 91 and 100 protein spots were found to show a significant change of more than 2-fold (P cell defense and rescue (28%), and with storage protein (18%). In endosperms, most of the identified proteins were involved in metabolism (37%), in energy (27%), and in protein synthesis and destination (11%). The most marked change was the increased abundance of many glycolytic enzymes together with the two fermentation enzymes pyruvate decarboxylase and alcohol dehydrogenase in the embryos during aging. We hypothesize that the decreased viability of hybrid rice seeds during artificial aging is caused by the development of hypoxic conditions in the embryos followed by ethanol accumulation.

  19. Effect of gibberellic acid on α-amylase and ribonuclease activities in rye endosperm after various periods of grain storage

    Directory of Open Access Journals (Sweden)

    T. Mierzwińska

    2015-01-01

    Full Text Available α-Amylase and ribonuclease activities were determined in embryoless rye half-seeds exhibiting different viaibility after various times of storage (2, 5 and 8 years. The half-seeds were incubated for 24, 48, 72 and 96 h with and without GA3. α-Amylase activity in the endosperm of rye grain stored for 2 and 5 years and incubated without the hormone increased considerably, whereas in 8-year grain, practically incapable of germination, it remained almost unchanged. GA3caused a considerable increase of α-amylase activity in all the tested samples. In grain stored for 2 and 5 years the enzyme activity reached its peak under the influence of the hormone earlier than in the control samples. The differences in ribonuclease activity between the particular samples were less pronounced, and the reaction to the hormone much weaker. The results indicate that the reaction of rye endosperm to GA3depends on the physiological properties of the grain.

  20. Evaluation of maize yield in an on-farm maize-soybean and maize-Lablab crop rotation systems in the Northern Guinea Savanna of Nigeria.

    Science.gov (United States)

    Okogun, J A; Sanginga, N; Abaidoo, R C

    2007-11-01

    An attempt was made to solving the problem of shortfall of fertilizer to maize production in the Northern Guinea Savanna (NGS) of Nigeria by harnessing the potentials of legume/cereal crop rotation in on-farm trials. The yield of maize that succeeded two soybean varieties and Lablab in a two-cycle of soybean/maize and Lablab/maize crop rotation in NGS Nigeria was assessed in researcher-managed and farmer-managed plots. Though maize that followed the soybean received between 5 kg N ha(-1) from improved soybean variety (TGx 1448-2E) and 17 kg N ha(-1) from farmer soybean variety (Samsoy-2) as N balance, this did not significantly (p = 0.05) affect the maize yields. The soybean shed 90-100% of its leaves at physiological maturity which resulted in about 110 kg N ha(-1) N uptake. This source of N might be one of the factors responsible for the increase in maize yield that followed soybean (20 to 24%) compared with continuous maize yield plot. Maize yield in previous Lablab plot was significantly (p = 0.05) higher than in all other treatments. Maize yield in farmer-managed plot ranged between 0.13 and 4.53 t ha(-1), maize yield in researcher-managed plot was over 200% higher than maize yield in farmer-managed plot because of poor crop management on the part of the farmer.

  1. Successfully introduce maize DNA fragments into rice

    Institute of Scientific and Technical Information of China (English)

    WANGKaizhi

    1994-01-01

    The maize DNA fragments was successfully incorporated into rice by Associate Prof WAN Wenju's research team at Hunan Agricultural College, Changsha, China. The new gene transferring rice is named Genetic Engineered Rice (GER) line.

  2. [Effects of nitrogen management on maize nitrogen utilization and residual nitrate nitrogen in soil under maize/soybean and maize/sweet potato relay strip intercropping systems].

    Science.gov (United States)

    Wang, Xiao-Chun; Yang, Wen-Yu; Deng, Xiao-Yan; Zhang, Qun; Yong, Tai-Wen; Liu, Wei-Guo; Yang, Feng; Mao, Shu-Ming

    2014-10-01

    A large amount of nitrogen (N) fertilizers poured into the fields severely pollute the environment. Reasonable application of N fertilizer has always been the research hotpot. The effects of N management on maize N utilization and residual nitrate N in soil under maize/soybean and maize/ sweet potato relay strip intercropping systems were reported in a field experiment in southwest China. It was found that maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato with an increase of 22.6% for maize yield after sustainable growing of maize/soybean intercropping system. Nitrate N accumulation in the 0-60 cm soil layer was 12.9% higher under maize/soybean intercropping than under maize/sweet potato intercropping. However, nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10.3% than when intercropped with sweet potato, indicating a decrease of N leaching loss. Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg · hm(-2). Further application of N fertilizer significantly enhanced nitrate leaching loss. Postponing N application increased nitrate accumulation in the 60-100 cm soil layer. The results suggested that N application rates and ratio of base to top dressing had different influences on maize N concentration and nitrate N between maize/soybean and maize/sweet potato intercropping. Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/soybean intercropping increased (with N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5) and

  3. Assessing white maize resistance to fumonisin contamination

    OpenAIRE

    Cao Caamaño, Ana; Butrón Gómez, Ana María; Ramos, Antonio J.; Marín, Sonia; Souto, Carlos; Santiago Carabelos, Rogelio

    2014-01-01

    Genetic improvement is an emerging method to reduce the levels of fumonisin (FB) contamination in maize, but breeding advances depend on the development of suitable methods to accurately assess the performance of different cultivars. Our study focused on characterizing a local isolate of Fusarium verticillioides; comparing artificial inoculation techniques with this isolate (injection into kernels and down the silk channel); and assessing white maize resistance under artificial vs. natural in...

  4. Differentiation of whole grain from refined wheat (T. aestivum) flour using lipid profile of wheat bran, germ, and endosperm with UHPLC-HRAM mass spectrometry”

    Science.gov (United States)

    A comprehensive analysis of wheat lipids from milling fractions of bran, germ, and endosperm were performed using ultra high-performance liquid chromatography high-resolution accurate-mass multi-stage mass spectrometry (UHPLC-HRAM-MSn) with electrospray ionization (ESI) and atmospheric pressure chem...

  5. Proteomics analysis reveals distinct involvement of embryo and endosperm proteins during seed germination in dormant and non-dormant rice seeds.

    Science.gov (United States)

    Xu, Heng-Heng; Liu, Shu-Jun; Song, Shun-Hua; Wang, Rui-Xia; Wang, Wei-Qing; Song, Song-Quan

    2016-06-01

    Seed germination is a complex trait which is influenced by many genetic, endogenous and environmental factors, but the key event(s) associated with seed germination are still poorly understood. In present study, the non-dormant cultivated rice Yannong S and the dormant Dongxiang wild rice seeds were used as experimental materials, we comparatively investigated the water uptake, germination time course, and the differential proteome of the effect of embryo and endosperm on germination of these two types of seeds. A total of 231 and 180 protein spots in embryo and endosperm, respectively, showed a significant change in abundance during germination. We observed that the important proteins associated with seed germination included those involved in metabolism, energy production, protein synthesis and destination, storage protein, cell growth and division, signal transduction, cell defense and rescue. The contribution of embryo and endosperm to seed germination is different. In embryo, the proteins involved in amino acid activation, sucrose cleavage, glycolysis, fermentation and protein synthesis increased; in endosperm, the proteins involved in sucrose cleavage and glycolysis decreased, and those with ATP and CoQ synthesis and proteolysis increased. Our results provide some new knowledge to understand further the mechanism of seed germination.

  6. Embryo growth, testa permeability, and endosperm weakening are major targets for the environmentally regulated inhibition of Lepidium sativum seed germination by myrigalone A

    Science.gov (United States)

    2012-01-01

    Myrigalone A (MyA) is a rare flavonoid in fruit leachates of Myrica gale, a deciduous shrub adapted to flood-prone habitats. As a putative allelochemical it inhibits seed germination and seedling growth. Using Lepidium sativum as a model target species, experiments were conducted to investigate how environmental cues modulate MyA’s interference with key processes of seed germination. Time course analyses of L. sativum testa and endosperm rupture under different light conditions and water potentials were combined with quantifying testa permeability, endosperm weakening, tissue-specific gibberellin (GA) and abscisic acid (ABA) contents, as well as embryo growth and apoplastic superoxide production important for cell expansion growth. Lepidium sativum testa permeability and early water uptake by imbibition is enhanced by MyA. During late germination, MyA inhibits endosperm weakening and embryo growth, both processes required for endosperm rupture. Inhibition of embryo cell expansion by MyA depends on environmental cues, which is evident from the light-modulated severity of the MyA-mediated inhibition of apoplastic superoxide accumulation. Several important key weakening and growth processes during early and late germination are targets for MyA. These effects are modulated by light conditions and ambient water potential. It is speculated that MyA is a soil seed bank-destroying allelochemical that secures the persistence of M. gale in its flood-prone environment. PMID:22821938

  7. Metodologias analíticas para determinação das fumonisinas em milho e alimentos à base de milho Analitycal metodologies for the determination of fumonisins in maize and maize-based food products

    Directory of Open Access Journals (Sweden)

    Celeste M. Lino

    2006-04-01

    Full Text Available Fumonisins are mycotoxins occurring worldwide, mainly in maize and maize-based food products, which could affect animal and human health. This paper reviews analytical methodologies for the determination of these fungal toxins in foods. It includes extraction, cleanup, derivatization procedures, detection, quantification, and confirmation procedures. Initial attempts at gas chromatographic methods and thin layer chromatography were supplanted by liquid chromatographic methods, mainly performed with fluorometric detection, or mass spectrometry detection, enabling the analysis of polar and thermolabile chemicals without chemical derivatization, which results in lower limits of detection. Alternative methods, such as enzyme linked immunosorbent assay or zone capillary zone electrophoresis, are also described.

  8. Maize leaf development under climate change scenarios

    Directory of Open Access Journals (Sweden)

    Nereu Augusto Streck

    2010-11-01

    Full Text Available The objective of this work was to simulate maize leaf development in climate change scenarios at Santa Maria, RS, Brazil, considering symmetric and asymmetric increases in air temperature. The model of Wang & Engel for leaf appearance rate (LAR, with genotype-specific coefficients for the maize variety BRS Missões, was used to simulate tip and expanded leaf accumulated number from emergence to flag leaf appearance and expansion, for nine emergence dates from August 15 to April 15. LAR model was run for each emergence date in 100-year climate scenarios: current climate, and +1, +2, +3, +4 and +5°C increase in mean air temperature, with symmetric and asymmetric increase in daily minimum and maximum air temperature. Maize crop failure due to frost decreased in elevated temperature scenarios, in the very early and very late emergence dates, indicating a lengthening in the maize growing season in warmer climates. The leaf development period in maize was shorter in elevated temperature scenarios, with greater shortening in asymmetric temperature increases, indicating that warmer nights accelerate vegetative development in maize.

  9. Climate Change and Maize Yield in Iowa.

    Science.gov (United States)

    Xu, Hong; Twine, Tracy E; Girvetz, Evan

    2016-01-01

    Climate is changing across the world, including the major maize-growing state of Iowa in the USA. To maintain crop yields, farmers will need a suite of adaptation strategies, and choice of strategy will depend on how the local to regional climate is expected to change. Here we predict how maize yield might change through the 21st century as compared with late 20th century yields across Iowa, USA, a region representing ideal climate and soils for maize production that contributes substantially to the global maize economy. To account for climate model uncertainty, we drive a dynamic ecosystem model with output from six climate models and two future climate forcing scenarios. Despite a wide range in the predicted amount of warming and change to summer precipitation, all simulations predict a decrease in maize yields from late 20th century to middle and late 21st century ranging from 15% to 50%. Linear regression of all models predicts a 6% state-averaged yield decrease for every 1°C increase in warm season average air temperature. When the influence of moisture stress on crop growth is removed from the model, yield decreases either remain the same or are reduced, depending on predicted changes in warm season precipitation. Our results suggest that even if maize were to receive all the water it needed, under the strongest climate forcing scenario yields will decline by 10-20% by the end of the 21st century.

  10. Pathogenicity of P. terrestris on Maize Seedlings

    Directory of Open Access Journals (Sweden)

    Jelena Lević

    2012-01-01

    Full Text Available Pathogenicity of P. terrestris was determined by the Knop’s medium slants method intest tubes. Isolates originated from the roots of maize (Zea mays L., barley (Hordeum vulgareL., Johnson grass (Sorghum halepense Pers., sorghum (Sorghum bicolour (L. Moench., garlic(Allium sativum L., onion (Allium cepa L., barnyard millet (Echinochloa crus-galli (L. P.Beauv.and green foxtail (Setaria viridis (L. P.B.. A fragment of a fungal colony, cultivated on PDA,was placed on the bottom of Knop’s medium slant in each test tube and then steriliseda maize seed was placed 2 cm away from the inoculum. After 21-day inoculation of seeds,the intensity of the development of symptoms on maize seedlings was estimated. The reddishor dark pigment on the root, mesocotyl and/or coleoptyl of seedlings was an indicatorfor the infection by the fungus under in vitro conditions. Based on the pathogenicity test,the isolates were classified into the following three groups: slightly (3 isolates, moderately(6 isolates and very pathogenic (6 isolates to maize seedlings. The obtained results showthat P. terrestris, originating from different hosts, can be a maize pathogen. These resultscan explain the high frequency and high incidence of this fungus on maize roots in Serbia.

  11. Concentration and dissipation of chlorantraniliprole and thiamethoxam residues in maize straw, maize, and soil.

    Science.gov (United States)

    He, Min; Song, Dan; Jia, Hong C; Zheng, Yongquan

    2016-09-01

    To study the dissipation rates and final residual levels of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil, two independent field trials were conducted during the 2014 cropping season in Beijing and Anhui Provinces of China. A 40% wettable powder (20% chlorantraniliprole + 20% thiamethoxam) was sprayed onto maize straw and soil at an application rate of 118 g of active ingredient per hectare (g a.i.ha(-1)). The residual concentrations were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry. The chlorantraniliprole half-lives in maize straw and soil were 9.0-10.8 and 9.5-21.7 days, respectively. The thiamethoxam half-lives in maize straw and soil were 8.4-9.8 and 4.3-11.7 days, respectively. The final residues of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil were measured after the pesticides had been sprayed two and three times with an interval of 7 days using 1 and 1.5 times the recommended rate (72 g a.i. ha(-1) and 108 g a.i. ha(-1), respectively). Representative maize straw, maize, and soil samples were collected after the last treatment at pre-harvest intervals of 7, 14, and 28 days. The chlorantraniliprole residue was below 0.01 mg kg(-1) in maize, between 0.01 and 0.31 mg kg(-1) in maize straw, and between 0.03 and 1.91 mg kg(-1) in soil. The thiamethoxam residue concentrations in maize, maize straw, and soil were <0.01, <0.01, and 0.01-0.03 mg kg(-1), respectively. The final pesticide residues on maize were lower than the maximum residue limit (MRL) of 0.02 mg kg(-1) after a 14-day pre-harvest interval. Therefore, a dosage of 72 g a.i. ha(-1) was recommended, as it can be considered safe to human beings and animals.

  12. Endoplasmic reticulum localization and activity of maize auxin biosynthetic enzymes.

    Science.gov (United States)

    Kriechbaumer, Verena; Seo, Hyesu; Park, Woong June; Hawes, Chris

    2015-09-01

    Auxin is a major growth hormone in plants and the first plant hormone to be discovered and studied. Active research over >60 years has shed light on many of the molecular mechanisms of its action including transport, perception, signal transduction, and a variety of biosynthetic pathways in various species, tissues, and developmental stages. The complexity and redundancy of the auxin biosynthetic network and enzymes involved raises the question of how such a system, producing such a potent agent as auxin, can be appropriately controlled at all. Here it is shown that maize auxin biosynthesis takes place in microsomal as well as cytosolic cellular fractions from maize seedlings. Most interestingly, a set of enzymes shown to be involved in auxin biosynthesis via their activity and/or mutant phenotypes and catalysing adjacent steps in YUCCA-dependent biosynthesis are localized to the endoplasmic reticulum (ER). Positioning of auxin biosynthetic enzymes at the ER could be necessary to bring auxin biosynthesis in closer proximity to ER-localized factors for transport, conjugation, and signalling, and allow for an additional level of regulation by subcellular compartmentation of auxin action. Furthermore, it might provide a link to ethylene action and be a factor in hormonal cross-talk as all five ethylene receptors are ER localized.

  13. Seeds of the Wild Progenitor of Maize Possess Bacteria That Antagonize Foodborne Pathogens.

    Science.gov (United States)

    Shehata, Hanan R; Griffiths, Mansel W; Raizada, Manish N

    2017-02-10

    Endophytes are microorganisms that inhabit plant tissues without causing disease. Some endophytes help their hosts to combat pathogens. Here we explored the hypothesis that the plant-derived foods consumed by humans and other animals host endophytes that also antagonize foodborne pathogens or food-rotting agents. Our laboratory previously cultured a library of bacterial endophytes from different members of the maize/corn family (Zea) including wild relatives. Here, 190 of these endophytes were screened for their ability to antagonize four foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Clostridium perfringens, and Salmonella enterica Newport) and a food spoiling agent (Pseudomonas fluorescens) using dual culture assays. Two Paenibacillus polymyxa endophytes (strains 3C6 and 3G11) were found to inhibit the growth of all five deleterious strains on agar. Using conserved polymerase chain reaction primers and sequencing, both beneficial endophytes were found to encode polymyxin genes, suggesting a potential antibacterial mechanism of action. Polymyxin production by both strains was confirmed using enzyme-linked immunosorbent assay. Strains 3C6 and 3G11 originated, respectively, from the seeds of the wild Central American maize species Zea diploperennis, and the wild ancestor of modern maize, Zea mays ssp parviglumis (Parviglumis). As the latter is the direct ancestor of modern maize, we discuss the role its endophyte(s) may have played in promoting crop domestication by suppressing foodborne pathogens and/or food-spoilage agents.

  14. Subcellular localization and functional domain studies of DEFECTIVE KERNEL1 in maize and Arabidopsis suggest a model for aleurone cell fate specification involving CRINKLY4 and SUPERNUMERARY ALEURONE LAYER1.

    Science.gov (United States)

    Tian, Qing; Olsen, Lene; Sun, Beimeng; Lid, Stein Erik; Brown, Roy C; Lemmon, Betty E; Fosnes, Kjetil; Gruis, Darren Fred; Opsahl-Sorteberg, Hilde-Gunn; Otegui, Marisa S; Olsen, Odd-Arne

    2007-10-01

    DEFECTIVE KERNEL1 (DEK1), which consists of a membrane-spanning region (DEK1-MEM) and a calpain-like Cys proteinase region (DEK1-CALP), is essential for aleurone cell formation at the surface of maize (Zea mays) endosperm. Immunolocalization and FM4-64 dye incubation experiments showed that DEK1 and CRINKLY4 (CR4), a receptor kinase implicated in aleurone cell fate specification, colocalized to plasma membrane and endosomes. SUPERNUMERARY ALEURONE LAYER1 (SAL1), a negative regulator of aleurone cell fate encoding a class E vacuolar sorting protein, colocalized with DEK1 and CR4 in endosomes. Immunogold localization, dual-axis electron tomography, and diffusion of fluorescent dye tracers showed that young aleurone cells established symplastic subdomains through plasmodesmata of larger dimensions than those connecting starchy endosperm cells and that CR4 preferentially associated with plasmodesmata between aleurone cells. Genetic complementation experiments showed that DEK1-CALP failed to restore wild-type phenotypes in maize and Arabidopsis thaliana dek1 mutants, and DEK1-MEM also failed to restore wild-type phenotypes in Arabidopsis dek1-1 mutants. Instead, ectopic expression of DEK1-MEM under the control of the cauliflower mosaic virus 35S promoter gave a dominant negative phenotype. These data suggest a model for aleurone cell fate specification in which DEK1 perceives and/or transmits a positional signal, CR4 promotes the lateral movement of aleurone signaling molecules between aleurone cells, and SAL1 maintains the proper plasma membrane concentration of DEK1 and CR4 proteins via endosome-mediated recycling/degradation.

  15. AFLATOXIN LEVELS IN LOCALLy GROWN MAIZE FROM MAKUENI ...

    African Journals Online (AJOL)

    2008-07-07

    Jul 7, 2008 ... Makueni District and to correlate aflatoxin levels to maize drying and storage practices. Also, ... Conclusion: High levels of aflatoxin in homegrown and purchased maize suggested that aflatoxin ..... Agriculture and Food Safety.

  16. Quality Protein Maize Response to Nitrogen Rate and Plant Density ...

    African Journals Online (AJOL)

    Quality Protein Maize Response to Nitrogen Rate and Plant Density in the Guinea Savanna Zone of Ghana. ... protein maize (Zea mays L.) hybrid to plant density and nitrogen (N) fertilizer. ... Optimal N rate was not affected by plant density.

  17. Effect of organic mulch materials on maize performance and weed ...

    African Journals Online (AJOL)

    Effect of organic mulch materials on maize performance and weed growth in the derived ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... of organic mulch materials (Plant and Animal) on the performance of maize and ...

  18. Genetic architecture of domestication-related traits in maize

    Science.gov (United States)

    Strong directional selection occurred during the domestication of maize from its wild ancestor teosinte, reducing its genetic diversity, particularly at genes controlling domestication-related traits. Nevertheless, variability for some domestication-related traits is maintained in maize. The genet...

  19. Processing maize flour and corn meal food products

    OpenAIRE

    2013-01-01

    Corn is the cereal with the highest production worldwide and is used for human consumption, livestock feed, and fuel. Various food technologies are currently used for processing industrially produced maize flours and corn meals in different parts of the world to obtain precooked refined maize flour, dehydrated nixtamalized flour, fermented maize flours, and other maize products. These products have different intrinsic vitamin and mineral contents, and their processing follows different pathwa...

  20. Strategic Marketing Problems in the Uganda Maize Seed Industry

    OpenAIRE

    Larson,Donald W.; Mbowa, Swaibu

    2004-01-01

    Strategic marketing issues and challenges face maize seed marketing firms as farmers increasingly adopt hybrid varieties in a modernizing third world country such as Uganda. The maize seed industry of Uganda has changed dramatically from a government owned, controlled, and operated industry to a competitive market oriented industry with substantial private firm investment and participation. The new maize seed industry is young, dynamic, growing and very competitive. The small maize seed marke...

  1. Study Progress on Tissue Culture of Maize Mature Embryo

    Science.gov (United States)

    Wang, Hongzhen; Cheng, Jun; Cheng, Yanping; Zhou, Xioafu

    It has been paid more and more attention on maize tissue culture as it is a basic work in maize genetic transformation, especially huge breakthrough has been made in maize tissue culture utilizing mature embryos as explants in the recent years. This paper reviewed the study progress on maize tissue culture and plant regeneration utilizing mature embryos as explants from callus induction, subculture, plant regeneration and browning reduction and so on.

  2. NMR spectroscopy and chemical studies of an arabinan-rich system from the endosperm of the seed of Gleditsia triacanthos.

    Science.gov (United States)

    Navarro, Diego A; Cerezo, Alberto S; Stortz, Carlos A

    2002-02-11

    Exhaustive extraction of the endosperm from the seed of Gleditsia triacanthos using water at room temperature and 50 degrees C left a residue, which was further extracted at 95 degrees C. Precipitation of this extract with 2-propanol yielded major amounts of galactomannan components, while the supernatant was mainly composed of arabinose-rich constituents. Two fractions were obtained by anion-exchange chromatography. The fraction that eluted with water is an arabinan with (1-->5) alpha-L linkages and branching mainly on C-2, accompanied with equal amounts of a low-galactose galactomannan oligosaccharide, and a small proportion of a beta-(1-->4)-galactan. The fraction eluted with an increased ionic strength consists mainly of a similar arabinan, and lower proportions of a high-galactose galactomannan, galactan, and protein. The arabinan moiety in both fractions was characterized by chemical analysis and 1D and 2D NMR spectroscopic techniques.

  3. Antimicrobial peptide (Cn-AMP2) from liquid endosperm of Cocos nucifera forms amyloid-like fibrillar structure.

    Science.gov (United States)

    Gour, Shalini; Kaushik, Vibha; Kumar, Vijay; Bhat, Priyanka; Yadav, Subhash C; Yadav, Jay K

    2016-04-01

    Cn-AMP2 is an antimicrobial peptide derived from liquid endosperm of coconut (Cocos nucifera). It consists of 11 amino acid residues and predicted to have high propensity for β-sheet formation that disposes this peptide to be amyloidogenic. In the present study, we have examined the amyloidogenic propensities of Cn-AMP2 in silico and then tested the predictions under in vitro conditions. The in silico study revealed that the peptide possesses high amyloidogenic propensity comparable with Aβ. Upon solubilisation and agitation in aqueous buffer, Cn-AMP2 forms visible aggregates that display bathochromic shift in the Congo red absorbance spectra, strong increase in thioflavin T fluorescence and fibrillar morphology under transmission electron microscopy. All these properties are typical of an amyloid fibril derived from various proteins/peptides including Aβ.

  4. Comparative Analysis of the Endosperm Proteins Separated by 2-D Electrophoresis for Two Cultivars of Hybrid Rice (Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Pingfang Yang; Shihua Shen; Tingyun Kuang

    2006-01-01

    Liangyoupeijiu is a two-parental-line, and Shanyou63 is a three-parental-line hybrid rice (Oryza sativa L.).Although both belong to the indica subspecies, they have obvious differences with respect to morphology,physiology and grain quality. Variations in endosperm protein compositions were studied by comparing the 2-D electrophoresis (2-DE) maps for these two cultivars of hybrid rice. After matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) analysis, a 21-kDa precursor of 19-kDa globulin was identified as the major storage protein for both cultivars. Some isoforms of peroxiredoxin and seed maturation protein were found to only exist in Shanyou63, whereas aldose reductase and starch granule-bound starch synthase were only detected in Liangyoupeijiu. These data might provide a foundation for further comparative studies of these two cultivars of hybrid rice.

  5. Water mobility in the endosperm of high beta-glucan barley mutants as studied by nuclear magnetic resonance imaging

    DEFF Research Database (Denmark)

    Seefeldt, Helene Fast; van den Berg, Frans; Klöckenberger, Walter

    2007-01-01

    1H NMR imaging (MRI) was used as a noninvasive technique to study water distribution and mobility in hydrated barley (Hordeum vulgare L.) seeds of accessions with varying content of beta glucan (BG), a highly hygroscopic cell wall component. High contents of BG in barley are unfavorable in malting...... were related to content and location of BG. Water mobility was investigated by following the rate and mode of desiccation in hydrated single seeds. In order to determine the different water components, a multispin echo experiment was set up to reveal the T2 transverse relaxation rates of water within...... desiccation. The embryo retained water even after 36 h of drying, whereas the endosperm showed low and heterogeneous mobility of the water after drying. The relaxation time constants indicated that the BG mutants had regions of much higher water mobility around the ventral crease compared to the control...

  6. Mixed cropping of groundnuts and maize in East Java

    NARCIS (Netherlands)

    Hoof, van W.C.H.

    1987-01-01

    Mixed cropping of groundnuts and maize in East Java was studied by means of a survey of farming practice and by field experiments. The influence of different sowing times and plant density of maize on the development and yield of groundnuts and maize were the main topics in this thesis. Plant arrang

  7. Quantitative disease resistance: dissection and adoption in maize

    Science.gov (United States)

    Maize is the world’s most widely cultivated crop, providing food, feed, and biofuel. Maize production is constantly threatened by the presence of devastating pathogens worldwide. Characterization of the genetic components underlying disease resistance is a major research area in maize which is highl...

  8. Mixed cropping of groundnuts and maize in East Java.

    NARCIS (Netherlands)

    Hoof, van W.C.H.

    1987-01-01

    Mixed cropping of groundnuts and maize in East Java was studied by means of a survey of farming practice and by field experiments. The influence of different sowing times and plant density of maize on the development and yield of groundnuts and maize were the main topics in this thesis. Plant arrang

  9. Fertilizer use efficiency by maize (Zea mays) and egusi- melon ...

    African Journals Online (AJOL)

    DBOY

    fertilizers by maize and egusi-melon in various ratios of mixtures in an ultisol in Nigeria. The experiment ... Fertilizer use efficiency (FUE) was generally higher in .... two equal splits at 3 and 8 weeks after planting (WAP) coinciding .... Effects of cropping ratios of maize and Egusi-melon on yield and yield components of maize.

  10. Oven-drying reduces ruminal starch degradation in maize kernels

    NARCIS (Netherlands)

    Ali, M.; Cone, J.W.; Hendriks, W.H.; Struik, P.C.

    2014-01-01

    The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels (consist

  11. Oven-drying reduces ruminal starch degradation in maize kernels

    NARCIS (Netherlands)

    Ali, M.; Cone, J.W.; Hendriks, W.H.; Struik, P.C.

    2014-01-01

    The degradation of starch largely determines the feeding value of maize (Zea mays L.) for dairy cows. Normally, maize kernels are dried and ground before chemical analysis and determining degradation characteristics, whereas cows eat and digest fresh material. Drying the moist maize kernels

  12. Biochar mitigation of allelopathy induced yield loss in continuous maize

    Science.gov (United States)

    Continuous maize yields are limited by the release of phytotoxic compounds as the previous year’s maize residue decomposes. We tested the hypothesis that soil biochar applications could help mitigate maize autotoxicity and the associated yield depression. Eighteen small field plots (23.7 m2) were es...

  13. An analysis of expressed sequence tags of developing castor endosperm using a full-length cDNA library

    Directory of Open Access Journals (Sweden)

    Wallis James G

    2007-07-01

    Full Text Available Abstract Background Castor seeds are a major source for ricinoleate, an important industrial raw material. Genomics studies of castor plant will provide critical information for understanding seed metabolism, for effectively engineering ricinoleate production in transgenic oilseeds, or for genetically improving castor plants by eliminating toxic and allergic proteins in seeds. Results Full-length cDNAs are useful resources in annotating genes and in providing functional analysis of genes and their products. We constructed a full-length cDNA library from developing castor endosperm, and obtained 4,720 ESTs from 5'-ends of the cDNA clones representing 1,908 unique sequences. The most abundant transcripts are genes encoding storage proteins, ricin, agglutinin and oleosins. Several other sequences are also very numerous, including two acidic triacylglycerol lipases, and the oleate hydroxylase (FAH12 gene that is responsible for ricinoleate biosynthesis. The role(s of the lipases in developing castor seeds are not clear, and co-expressing of a lipase and the FAH12 did not result in significant changes in hydroxy fatty acid accumulation in transgenic Arabidopsis seeds. Only one oleate desaturase (FAD2 gene was identified in our cDNA sequences. Sequence and functional analyses of the castor FAD2 were carried out since it had not been characterized previously. Overexpression of castor FAD2 in a FAH12-expressing Arabidopsis line resulted in decreased accumulation of hydroxy fatty acids in transgenic seeds. Conclusion Our results suggest that transcriptional regulation of FAD2 and FAH12 genes maybe one of the mechanisms that contribute to a high level of ricinoleate accumulation in castor endosperm. The full-length cDNA library will be used to search for additional genes that affect ricinoleate accumulation in seed oils. Our EST sequences will also be useful to annotate the castor genome, which whole sequence is being generated by shotgun sequencing at

  14. Rice endosperm is cost-effective for the production of recombinant griffithsin with potent activity against HIV.

    Science.gov (United States)

    Vamvaka, Evangelia; Arcalis, Elsa; Ramessar, Koreen; Evans, Abbey; O'Keefe, Barry R; Shattock, Robin J; Medina, Vicente; Stöger, Eva; Christou, Paul; Capell, Teresa

    2016-06-01

    Protein microbicides containing neutralizing antibodies and antiviral lectins may help to reduce the rate of infection with human immunodeficiency virus (HIV) if it is possible to manufacture the components in large quantities at a cost affordable in HIV-endemic regions such as sub-Saharan Africa. We expressed the antiviral lectin griffithsin (GRFT), which shows potent neutralizing activity against HIV, in the endosperm of transgenic rice plants (Oryza sativa), to determine whether rice can be used to produce inexpensive GRFT as a microbicide ingredient. The yield of (OS) GRFT in the best-performing plants was 223 μg/g dry seed weight. We also established a one-step purification protocol, achieving a recovery of 74% and a purity of 80%, which potentially could be developed into a larger-scale process to facilitate inexpensive downstream processing. (OS) GRFT bound to HIV glycans with similar efficiency to GRFT produced in Escherichia coli. Whole-cell assays using purified (OS) GRFT and infectivity assays using crude extracts of transgenic rice endosperm confirmed that both crude and pure (OS) GRFT showed potent activity against HIV and the crude extracts were not toxic towards human cell lines, suggesting they could be administered as a microbicide with only minimal processing. A freedom-to-operate analysis confirmed that GRFT produced in rice is suitable for commercial development, and an economic evaluation suggested that 1.8 kg/ha of pure GRFT could be produced from rice seeds. Our data therefore indicate that rice could be developed as an inexpensive production platform for GRFT as a microbicide component.

  15. Bioengineered 'golden' indica rice cultivars with beta-carotene metabolism in the endosperm with hygromycin and mannose selection systems.

    Science.gov (United States)

    Datta, Karabi; Baisakh, Niranjan; Oliva, Norman; Torrizo, Lina; Abrigo, Editha; Tan, Jing; Rai, Mayank; Rehana, Sayda; Al-Babili, Salim; Beyer, Peter; Potrykus, Ingo; Datta, Swapan K

    2003-03-01

    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 beta-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.

  16. Defective kernel mutants of maize. I. Genetic and lethality studies.

    Science.gov (United States)

    Neuffer, M G; Sheridan, W F

    1980-08-01

    A planting of 3,919 M(1) kernels from normal ears crossed by EMS-treated pollen produced 3,461 M(1) plants and 3,172 selfed ears. These plants yielded 2,477 (72%) total heritable changes; the selfed ears yielded 2,457 (78%) recessive mutants, including 855 (27%) recessive kernel mutants and 8 (0.23%) viable dominant mutants. The ratio of recessive to dominant mutants was 201:1. The average mutation frequency for four known loci was three per 3,172 genomes analyzed. The estimated total number of loci mutated was 535 and the estimated number of kernel mutant loci mutated was 285. Among the 855 kernel mutants, 432 had a nonviable embryo, and 59 germinated but had a lethal seedling. A sample of 194 of the latter two types was tested for heritability, lethality, chromosome arm location and endosperm-embryo interaction between mutant and nonmutant tissues in special hyper-hypoploid combinations produced by manipulation of B-A translocations. The selected 194 mutants were characterized and catalogued according to endosperm phenotype and investigated to determine their effects on the morphology and development of the associated embryo. The possibility of rescuing some of the lethal mutants by covering the mutant embryo with a normal endosperm was investigated. Ninety of these 194 mutants were located on 17 of the 18 chromosome arms tested. Nineteen of the located mutants were examined to determine the effect of having a normal embryo in the same kernel with a mutant endosperm, and vice versa, as compared to the expression observed in kernels with both embryo and endosperm in a mutant condition. In the first situation, for three of the 19 mutants, the mutant endosperm was less extreme (the embryo helped); for seven cases, the mutant endosperm was more extreme (the embryo hindered); and for nine cases, there was no change. In the reverse situation, for four cases the normal endosperm helped the mutant embryo; for 14 cases there was no change and one case was inconclusive.

  17. Fungal growth and fusarium mycotoxin content in isogenic traditional maize and genetically modified maize grown in France and Spain.

    Science.gov (United States)

    Bakan, B; Melcion, D; Richard-Molard, D; Cahagnier, B

    2002-02-13

    Fungi of the genus Fusarium are common fungal contaminants of maize and are also known to produce mycotoxins. Maize that has been genetically modified to express a Bt endotoxin has been used to study the effect of insect resistance on fungal infection of maize grains by Fusarium species and their related mycotoxins. Maize grain from Bt hybrids and near-isogenic traditional hybrids was collected in France and Spain from the 1999 crop, which was grown under natural conditions. According to the ergosterol level, the fungal biomass formed on Bt maize grain was 4-18 times lower than that on isogenic maize. Fumonisin B(1) grain concentrations ranged from 0.05 to 0.3 ppm for Bt maize and from 0.4 to 9 ppm for isogenic maize. Moderate to low concentrations of trichothecenes and zearalenone were measured on transgenic as well as on non-transgenic maize. Nevertheless, significant differences were obtained in certain regions. The protection of maize plants against insect damage (European corn borer and pink stem borer) through the use of Bt technology seems to be a way to reduce the contamination of maize by Fusarium species and the resultant fumonisins in maize grain grown in France and Spain.

  18. Household dietary exposure to aflatoxins from maize and maize products in Kenya.

    Science.gov (United States)

    Kilonzo, Robert M; Imungi, Jasper K; Muiru, William M; Lamuka, Peter O; Njage, Patrick M Kamau

    2014-01-01

    Aflatoxicosis has repeatedly affected Kenyans, particularly in the eastern region, due to consumption of contaminated maize. However, save for the cases of acute toxicity, the levels of sub-lethal exposure have not been adequately assessed. It is believed that this type of exposure does exist even during the seasons when acute toxicity does not occur. This study, therefore, was designed to assess the exposure of households to aflatoxins through consumption of maize and maize products. Twenty samples each of maize kernels, muthokoi and maize meal were randomly sampled from households in Kibwezi District of Makueni County in Eastern Kenya and analysed for aflatoxin contamination. The samples were quantitatively analysed for aflatoxin contamination using HPLC. The uncertainty and variability in dietary exposure was quantitatively modelled in Ms Excel using Monte Carlo simulation in @Risk software. Aflatoxins were found in 45% of maize kernels at between 18 and 480 μg kg⁻¹, 20% of muthokoi at between 12 and 123 μg kg⁻¹, and 35% of maize meal at between 6 and 30 μg kg⁻¹. The mean dietary exposure to aflatoxin in maize kernels was 292 ± 1567 ng kg⁻¹ body weight day⁻¹, while the mean dietary exposure to aflatoxin in maize meal and muthokoi were 59 ± 62 and 27 ± 154 ng kg⁻¹ body weight day⁻¹ respectively. The results showed that the amount and frequency of consumption of the three foods is the more important contributing factor than the mean aflatoxin concentration levels, to the risk of dietary exposure to aflatoxins.

  19. Microbial symbionts in insects influence down-regulation of defense genes in maize.

    Directory of Open Access Journals (Sweden)

    Kelli L Barr

    Full Text Available Diabrotica virgifera virgifera larvae are root-feeding insects and significant pests to maize in North America and Europe. Little is known regarding how plants respond to insect attack of roots, thus complicating the selection for plant defense targets. Diabrotica virgifera virgifera is the most successful species in its genus and is the only Diabrotica beetle harboring an almost species-wide Wolbachia infection. Diabrotica virgifera virgifera are infected with Wolbachia and the typical gut flora found in soil-living, phytophagous insects. Diabrotica virgifera virgifera larvae cannot be reared aseptically and thus, it is not possible to observe the response of maize to effects of insect gut flora or other transient microbes. Because Wolbachia are heritable, it is possible to investigate whether Wolbachia infection affects the regulation of maize defenses. To answer if the success of Diabrotica virgifera virgifera is the result of microbial infection, Diabrotica virgifera virgifera were treated with antibiotics to eliminate Wolbachia and a microarray experiment was performed. Direct comparisons made between the response of maize root tissue to the feeding of antibiotic treated and untreated Diabrotica virgifera virgifera show down-regulation of plant defenses in the untreated insects compared to the antibiotic treated and control treatments. Results were confirmed via QRT-PCR. Biological and behavioral assays indicate that microbes have integrated into Diabrotica virgifera virgifera physiology without inducing negative effects and that antibiotic treatment did not affect the behavior or biology of the insect. The expression data and suggest that the pressure of microbes, which are most likely Wolbachia, mediate the down-regulation of many maize defenses via their insect hosts. This is the first report of a potential link between a microbial symbiont of an insect and a silencing effect in the insect host plant. This is also the first expression

  20. Cytogenetic Mapping of Disease Resistance Genes and Analysis of Their Distribution Features on Chromosomes in Maize

    Institute of Scientific and Technical Information of China (English)

    Li Li-jia; Song Yun-chun

    2003-01-01

    Cytogenetic maps of four clusters of disease resistance genes were generated by ISH of the two RFLP markers tightly linked to and flanking each of maize resistance genes and the cloned resistance genes from other plant species onto maize chromosomes, combining with data published before. These genes include Helminthosporium turcium Pass resistance genes Ht1, Htn1 and Ht2, Helminthosporium maydis Nisik resistance genes Rhm1 and Rhm2, maize dwarf mosaic virus resistance gene Mdm1, wheat streak mosaic virus resistance gene Wsm1, Helminthosporium carbonum ULLstrup resistance gene Hml and the cloned Xanthomonas oryzae pv. Oryzae resistance gene Xa21 of rice, Cladosporium fulvum resistance genes Cf-9 and Cf-2.1 of tomato,and Pseudomonas syringae resistance gene RPS2 of Arabidopsis. Most of the tested disease resistance genes located on the four chromosomes, i.e., chromosomes1, 3, 6 and 8, and they closely distributed at the interstitial regions of these chromosomal long arms with percentage distances ranging 31.44(±3.72)-72.40(±3.25) except for genes Rhm1, Rhm2, Mdm1 and Wsm1 which mapped on the satellites of the short arms of chromosome6. It showed that the tested RFLP markers and genes were duplicated or triplicated in maize genome. Homology and conservation of disease resistance genes among species, and relationship between distribution features and functions of the genes were discussed. The results provide important scientific basis for deeply understanding structure and function of disease resistance genes and breeding in maize.

  1. 植物胚乳发育的表观遗传学调控%Epigenetic Regulation in Plant Endosperm Development

    Institute of Scientific and Technical Information of China (English)

    张美善; 刘宝

    2012-01-01

    In angiosperms, seed development initiates from double fertilization, which produces a diploid embryo and a triploid endosperm. The endosperm, a terminally differentiated tissue that nourishes the embryo during seed development and germination, is the prominent tissue of imprinting in plants. Proper endosperm development is crucial for normal embryo and seed development. The expression of imprinted genes is regulated by epigenetic mechanisms, including DNA methylation, H3K27 trimethylation and PollV-dependent siRNA (p4-siRNA). Such epigenetic regulation of imprinting is vital to proper endosperm development and seed viability. Recent studies show that endosperm DNA methylation is reduced genome-wide, which likely originates from demethylation in the central cell nucleus of the female gametophyte. This review focuses on the latest research advances in the epigenetic regulation in plant seed development, including the mechanism of plant genomic imprinting and dynamics of the genome-wide demethylation in endosperm.%被子植物的种子发育从双受精开始,产生二倍体的胚和三倍体的胚乳.在种子发育和萌发过程中,胚乳向胚组织提供营养物质,因此胚乳对胚和种子的正常生长发育至关重要.开花植物发生基因组印迹的主要器官是胚乳.印迹基因的表达受表观遗传学机制的调控,包括DNA甲基化和组蛋白H3K27甲基化修饰以及依赖于PollV的siRNAs(p4-siRNAs)调控.基因组印迹的表观遗传学调控对胚乳的正常发育和种子育性具有不可或缺的重要作用.最新研究显示,胚乳的整个基因组DNA甲基化水平降低,而且去甲基化作用可能源于雌配子体的中央细胞.该文综述了种子发育的表观遗传学调控机制,包括基因组印迹机制以及胚乳基因组DNA甲基化变化研究的最新进展.

  2. Communication Links

    OpenAIRE

    2003-01-01

    This interactive tutorial helps learners to: Identify key upward, lateral, downward, and informal communication links in their organizations. , Reflect on the benefits, control, satisfaction, information filters, and feedback mechanism of various communication links in the organizations. OCL1000 Communicating Change in Complex Organizations

  3. Operative links

    DEFF Research Database (Denmark)

    Wistoft, Karen

    2010-01-01

    as networks: second, a semantic perspective on discourses and concepts of health, and, third, a health pedagogical perspective on participation, intervention, and roles. This paper argues for the importance of 'operative links' between different levels in health strategies. It is proposed that such links...

  4. Field effects of cadmium contamination in the radiation characteristics of maize

    Science.gov (United States)

    Illes, B.; Anda, A.

    2012-04-01

    Cadmium is one of the most common toxic heavy metals in our environment. Cadmium is a particularly dangerous element, because it dissolves readily, making it easily available to plants. It is thus able to accumulate in various links in the food chain, finally reaching humans, at the end of the chain. Adverse effects on human body was reported in 1858 at first. If it enters the body, damage to health, cause changes and can also cause cancer. Our study was designated to simulate the effects of cadmium on maize in field conditions, during the 2011 growing season. The impact of cadmium on maize was investigated at the Agro-meteorological Research Station in Keszthely. A Swiss-bred maize hybrid, Sperlona (FAO 340), with a short vegetation period, was sown in the experiments at the plant density (70,000 plants per hectare) widely used under Hungarian climatic conditions for growing grain maize. Effects of cadmium on corn life were studied under two water supplies. Evapotranspirometers of the Thornthwaite type were used for the "ad libitum" treatment and the the rainfed variant was sown in field plots. 0,5 M concentration of cadmium was used, which was sprayed weekly. The aim of the investigation was to simulate impact of atmospheric pollution of traffic origin (low and frequent doses in the field). Plant height was registered weekly similarly to leaf area index (LAI). Albedo was measured by pyranometers of the CMA-11 type (Kipp & Zonen, Vaisala). From this the most important radiative properties were calculated, so the net radiation balance, latent heat, sensible heat and the Bowen ratio. The values of LAI for the cadmium contaminated maize were significantly lower compared to the control maize. The net radiation balance was about the same in both treatments. Cadmium causes the latent heat decreased, while the sensible heat increased compared to the control treatment. The Bowen ratio in the polluted crops was higher, than the cadmium-untreated area. The yield of maize

  5. Evidence for an evolutionarily conserved interaction between cell wall biosynthesis and flowering in maize and sorghum

    Directory of Open Access Journals (Sweden)

    Thompson Karen J

    2002-01-01

    Full Text Available Abstract Background Factors that affect flowering vary among different plant species, and in the grasses in particular the exact mechanism behind this transition is not fully understood. The brown midrib (bm mutants of maize (Zea mays L., which have altered cell wall composition, have different flowering dynamics compared to their wild-type counterparts. This is indicative of a link between cell wall biogenesis and flowering. In order to test whether this relationship also exists in other grasses, the flowering dynamics in sorghum (Sorghum bicolor (L. Moench were investigated. Sorghum is evolutionarily closely related to maize, and a set of brown midrib (bmr mutants similar to the maize bm mutants is available, making sorghum a suitable choice for study in this context. Results We compared the flowering time (time to half-bloom of several different bmr sorghum lines and their wild-type counterparts. This revealed that the relationship between cell wall composition and flowering was conserved in sorghum. Specifically, the mutant bmr7 flowered significantly earlier than the corresponding wild-type control, whereas the mutants bmr2, bmr4, bmr6, bmr12, and bmr19 flowered later than their wild-type controls. Conclusion The change in flowering dynamics in several of the brown midrib sorghum lines provides evidence for an evolutionarily conserved mechanism that links cell wall biosynthesis to flowering dynamics. The availability of the sorghum bmr mutants expands the germplasm available to investigate this relationship in further detail.

  6. Getting domestication straight: ramosa1 in maize.

    Science.gov (United States)

    Dempewolf, Hannes

    2010-04-01

    Knowledge of the identities and characteristics of genes that govern the dramatic phenotypic differences between cultivated plants and their wild ancestors has greatly enhanced our understanding of the domestication process. In this issue of Molecular Ecology, Sigmon & Vollbrecht report the discovery of a new maize domestication gene, ramosa1, which encodes a putative transcription factor in the ramosa developmental pathway. Ramosa1 appears to be instrumental in determining the straightness of kernel rows on the maize cob. The key domestication alleles at ramosa1 are prevalent in landraces of maize. These results reinforce findings from previous studies of crop evolution by highlighting the importance of standing genetic variation and changes in transcriptional regulators in domestication. The evolutionary genetics of domestication also provides a framework for predicting the evolutionary response of organisms to strong human-induced selection pressures over limited time intervals.

  7. MORPHOLOGICAL AND THERMAL PROPERTIES OF MAIZE STARCH

    Directory of Open Access Journals (Sweden)

    Elena Corina Popescu

    2010-01-01

    Full Text Available Maize, rice, wheat and potato are the main sources of starches which differ significantly in composition, morphology,thermal, rheological and retrogradation properties. Starch has unique thermal properties and functionality that havepermitted its wide use in food products and industrial applications.The structure of the starch granule results from the physical arrangement of amylose and amylopectin. Amylose contentof starches from different maize types ranged between 15.3% and 25.1%. Amylopectin is considered responsible for thecrystalline structure of starch granules.The morphological and physicochemical characteristics of maize starch are related to the enzymes involved in itsbiosynthesis.The surface of the starch granule plays a fundamental rôle as the first barrier to processes such as granule hydration,enzyme attack, and chemical reaction with modifying agents. Major parameters describing the solid surface are:specific surface area, total pore volume, mean pore radius (diameter and pore volume distribution in relation to poreradius (diameter.

  8. Economic efficiency of the maize grain

    Directory of Open Access Journals (Sweden)

    Ana Mariana Dincu

    2014-11-01

    Full Text Available In this work, was calculated and the level of profitability for several levels of production for grain maize cultivation. We chose corn because it is one of the most important forage crops, we could say even the largest, occupying third place among cultivated plants worldwide. Along with wheat and barley, the food is the biggest part of the population in the world, directly or converted to animal products. Maize can be used in animal feed in various forms. The most used is corn grain, which is characterized by a very high nutritional value, this product is properly regarded as a feed concentrate. Culture of maize have been designed two levels of production: 4000 kg / ha and 6000 kg / ha.

  9. Digital gene expression signatures for maize development.

    Science.gov (United States)

    Eveland, Andrea L; Satoh-Nagasawa, Namiko; Goldshmidt, Alexander; Meyer, Sandra; Beatty, Mary; Sakai, Hajime; Ware, Doreen; Jackson, David

    2010-11-01

    Genome-wide expression signatures detect specific perturbations in developmental programs and contribute to functional resolution of key regulatory networks. In maize (Zea mays) inflorescences, mutations in the RAMOSA (RA) genes affect the determinacy of axillary meristems and thus alter branching patterns, an important agronomic trait. In this work, we developed and tested a framework for analysis of tag-based, digital gene expression profiles using Illumina's high-throughput sequencing technology and the newly assembled B73 maize reference genome. We also used a mutation in the RA3 gene to identify putative expression signatures specific to stem cell fate in axillary meristem determinacy. The RA3 gene encodes a trehalose-6-phosphate phosphatase and may act at the interface between developmental and metabolic processes. Deep sequencing of digital gene expression libraries, representing three biological replicate ear samples from wild-type and ra3 plants, generated 27 million 20- to 21-nucleotide reads with frequencies spanning 4 orders of magnitude. Unique sequence tags were anchored to 3'-ends of individual transcripts by DpnII and NlaIII digests, which were multiplexed during sequencing. We mapped 86% of nonredundant signature tags to the maize genome, which associated with 37,117 gene models and unannotated regions of expression. In total, 66% of genes were detected by at least nine reads in immature maize ears. We used comparative genomics to leverage existing information from Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) in functional analyses of differentially expressed maize genes. Results from this study provide a basis for the analysis of short-read expression data in maize and resolved specific expression signatures that will help define mechanisms of action for the RA3 gene.

  10. Immunochemical identification of gelsolin in maize pollen

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Gelsolin is a representative of a type of actin-binding proteins (ABPs) universally found in eukaryotes. It plays role in nucleation, capping and severing of actin filaments in vitro. In our experiment, gelsolin was purified from pig plasma and the polyclonal antibodies against it were prepared. The crude extracts of maize pollen were immunodetected by Western-blotting with polyclonal antibody and monoclonal antibody respectively. The immunodetection results show that gelsolin exists in maize pollen and its molecular weight is about 91 ku, similar to that of gelsolin found in animal tissues.

  11. [Effect of dynamic high-pressure micro-fluidization on the structure of maize amylose].

    Science.gov (United States)

    Tu, Zong-Cai; Yin, Yue-Bin; Zhang, Qiu; Wang, Hui

    2013-05-01

    The effect of dynamic high-pressure micro-fluidization (DHPM) at 80, 120, 160, and 200 MPa on the structure of maize amylose was investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), Xray diffraction, and FT-IR spectroscopy. SEM analysis showed that the surface appearances of maize amylose were altered and the starch granules were partially congregated together after DHPM treatment. AFM images showed that the treated starch molecules are cross-linked to each other and arranged in a close mesh structure. Xray diffraction spectra and IR spectra indicated that relative crystallinity declined gradually with the pressure increasing. The results provide a theoretical basis for starch modification of DHPM.

  12. Molecular analysis of endo-β-mannanase genes upon seed imbibition suggest a cross-talk between radicle and micropylar endosperm during germination of Arabidopsis thaliana

    Science.gov (United States)

    Iglesias-Fernández, Raquel; del Carmen Rodríguez-Gacio, María; Barrero-Sicilia, Cristina; Carbonero, Pilar

    2011-01-01

    The endo-β-mannanase (MAN) family is represented in the Arabidopsis genome by eight members, all with canonical signal peptides and only half of them being expressed in germinating seeds. The transcripts of these genes were localized in the radicle and micropylar endosperm (ME) before radicle protrusion and this expression disappears as soon as the endosperm is broken by the emerging radicle tip. However, only three of these MAN genes, AtMAN5, AtMAN7 and especially AtMAN6 influence the germination time (t50) as assessed by the analysis of the corresponding knock-out lines. The data suggest a possible interaction between embryo and ME regarding the role of MAN during the Arabidopsis germination process. PMID:21301215

  13. Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation

    Directory of Open Access Journals (Sweden)

    Walaa Kamel Mousa

    2015-10-01

    Full Text Available Wild maize (teosinte has been reported to be less susceptible to pests than their modern maize (corn relatives. Endophytes, defined as microbes that inhabit plants without causing disease, are known for their ability to antagonize plant pests and pathogens. We hypothesized that the wild relatives of modern maize may host endophytes that combat pathogens. Fusarium graminearum is the fungus that causes Gibberella Ear Rot (GER in modern maize and produces the mycotoxin, deoxynivalenol (DON. In this study, 215 bacterial endophytes, previously isolated from diverse maize genotypes including wild teosintes, traditional landraces and modern varieties, were tested for their ability to antagonize F. graminearum in vitro. Candidate endophytes were then tested for their ability to suppress GER in modern maize in independent greenhouse trials. The results revealed that three candidate endophytes derived from wild teosintes were most potent in suppressing F. graminearum in vitro and GER in a modern maize hybrid. These wild teosinte endophytes could suppress a broad spectrum of fungal pathogens of modern crops in vitro. The teosinte endophytes also suppressed DON mycotoxin during storage to below acceptable safety threshold levels. A fourth, less robust anti-fungal strain was isolated from a modern maize hybrid. Three of the anti-fungal endophytes were predicted to be Paenibacillus polymyxa, along with one strain of Citrobacter. Microscopy studies suggested a fungicidal mode of action by all four strains. Molecular and biochemical studies showed that the P. polymyxa strains produced the previously characterized anti-Fusarium compound, fusaricidin. Our results suggest that the wild relatives of modern crops may serve as a valuable reservoir for endophytes in the ongoing fight against serious threats to modern agriculture. We discuss the possible impact of crop evolution and domestication on endophytes in the context of plant defense.

  14. Occurrence of toxigenic fungi in maize and maize-gluten meal from Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Kashif SALEEMI

    2012-05-01

    Full Text Available The present study was designed to isolate and identify toxigenic mycoflora of maize and maize-gluten meal. A total of 82 samples of maize and 8 samples of maize-gluten meal were collected from Faisalabad district of Pakistan over a period of two years. These samples were inoculated on different culture media. Fungal contamination of maize and maize-gluten was 56% and 75% of samples, respectively. Isolation frequencies of different genera isolated from maize were Aspergillus 33%; Penicillium 28%; Fusarium 10%; and Alternaria 1%. Isolation frequency among species was maximum for P. verrucosum, followed by A. niger aggregates, A. ochraceous, A. flavus, P. chrysogenum, A. parasiticus, A. carbonarius, Fusarium spp. and Alternaria spp. Relative density of Aspergillus isolates was maximum for A. niger aggregates and A. ochraceous (30% each followed by A. flavus (26%, A. parasiticus (11% and A. carbonarius (3%. Percentage of toxigenic fungi among Aspergillus isolates was 52%. Aflatoxigenic isolates of A. flavus and A. parasiticus were 43 and 67% and ochratoxigenic isolates of A. carbonarius, A. ochraceous and A. niger aggregates were 100, 63 and 38%, respectively. Aspergillus parasiticus produced higher concentrations of AFB1 (maximum 1374.23 ng g-1 than A. flavus (maximum 635.50 ng g-1. Ochratoxin A production potential of A. ochraceous ranged from 1.81 to 9523.1 ng g-1, while in A. niger aggregates it was 1.30 to 1758.6 ng g-1. Isolation frequencies of fungal genera from maize-gluten meal were Aspergillus (63% and Penicillium (50%. A. flavus was the most frequently isolated species. Percentage of toxigenic fungi among Aspergillus isolates was 40%. Aflatoxigenic isolates of A. flavus were 33% and ochratoxigenic isolates of A. ochraceous were 100%.

  15. Cloning and functional expression of a cDNA encoding stearoyl-ACP Δ9-desaturase from the endosperm of coconut (Cocos nucifera L.).

    Science.gov (United States)

    Gao, Lingchao; Sun, Ruhao; Liang, Yuanxue; Zhang, Mengdan; Zheng, Yusheng; Li, Dongdong

    2014-10-01

    Coconut (Cocos nucifera L.) is an economically tropical fruit tree with special fatty acid compositions. The stearoyl-acyl carrier protein (ACP) desaturase (SAD) plays a key role in the properties of the majority of cellular glycerolipids. In this paper, a full-length cDNA of a stearoyl-acyl carrier protein desaturase, designated CocoFAD, was isolated from cDNA library prepared from the endosperm of coconut (C. nucifera L.). An 1176 bp cDNA from overlapped PCR products containing ORF encoding a 391-amino acid (aa) protein was obtained. The coded protein was virtually identical and shared the homology to other Δ9-desaturase plant sequences (greater than 80% as similarity to that of Elaeis guineensis Jacq). The real-time fluorescent quantitative PCR result indicated that the yield of CocoFAD was the highest in the endosperm of 8-month-old coconut and leaf, and the yield was reduced to 50% of the highest level in the endosperm of 15-month-old coconut. The coding region showed heterologous expression in strain INVSc1 of yeast (Saccharomyces cerevisiae). GC-MS analysis showed that the levels of palmitoleic acid (16:1) and oleic acid (18:1) were improved significantly; meanwhile stearic acid (18:0) was reduced. These results indicated that the plastidial Δ9 desaturase from the endosperm of coconut was involved in the biosynthesis of hexadecenoic acid and octadecenoic acid, which was similar with other plants. These results may be valuable for understanding the mechanism of fatty acid metabolism and the genetic improvement of CocoFAD gene in palm plants in the future.

  16. Regulation of FA and TAG biosynthesis pathway genes in endosperms and embryos of high and low oil content genotypes of Jatropha curcas L.

    Science.gov (United States)

    Sood, Archit; Chauhan, Rajinder Singh

    2015-09-01

    The rising demand for biofuels has raised concerns about selecting alternate and promising renewable energy crops which do not compete with food supply. Jatropha (Jatropha curcas L.), a non-edible energy crop of the family euphorbiaceae, has the potential of providing biodiesel feedstock due to the presence of high proportion of unsaturated fatty acids (75%) in seed oil which is mainly accumulated in endosperm and embryo. The molecular basis of seed oil biosynthesis machinery has been studied in J. curcas, however, what genetic differences contribute to differential oil biosynthesis and accumulation in genotypes varying for oil content is poorly understood. We investigated expression profile of 18 FA and TAG biosynthetic pathway genes in different developmental stages of embryo and endosperm from high (42%) and low (30%) oil content genotypes grown at two geographical locations. Most of the genes showed relatively higher expression in endosperms of high oil content genotype, whereas no significant difference was observed in endosperms versus embryos of low oil content genotype. The promoter regions of key genes from FA and TAG biosynthetic pathways as well as other genes implicated in oil accumulation were analyzed for regulatory elements and transcription factors specific to oil or lipid accumulation in plants such as Dof, CBF (LEC1), SORLIP, GATA and Skn-1_motif etc. Identification of key genes from oil biosynthesis and regulatory elements specific to oil deposition will be useful not only in dissecting the molecular basis of high oil content but also improving seed oil content through transgenic or molecular breeding approaches. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  17. Roles of the haustorium and endosperm during the development of seedlings of Acrocomia aculeata (Arecaceae): dynamics of reserve mobilization and accumulation.

    Science.gov (United States)

    Mazzottini-Dos-Santos, Hellen Cássia; Ribeiro, Leonardo Monteiro; Oliveira, Denise Maria Trombert

    2016-11-24

    The mobilization of palm seed reserves is a complex process because of the abundance and diversity of stored compounds and results from the development of a highly specialized haustorium. This work focused on the important Neotropical oleaginous palm Acrocomia aculeata, with the aim of defining phases of seedling development associated with mobilization of reserves and elucidating the role of haustorium and endosperm in this process. Standard methods were performed, including biometric, anatomical, and histochemical analyses, as well as the evaluation of the activities of the enzymes endo-β-mannanase and lipase, throughout the reserve mobilization in seeds during germination and in seedlings. Seeds of A. aculeata stored large quantities of proteins, lipids, and polysaccharides in the embryo and endosperm. The mobilization of reserves initiated in the haustorium during germination and subsequently occurred in the endosperm adjacent to the haustorium, forming a gradually increasing zone of digestion. Proteins and polysaccharides were the first to be mobilized, followed by lipids and cell wall constituents. The haustorium activates and controls the mobilization, forming transitory reserves and translocating them to the vegetative axis, while the endosperm, which also has an active role, serves as a site of intense enzymatic activity associated with protein bodies. Seedling development can be described as occurring in six phases over a long period (approximately 150 days) due to the large amount of seed reserves. This process exhibits an alternation between stages of accumulation and translocation of protein, lipid, and carbohydrate reserves in the haustorium, which favors the seedling establishment and the reproductive success of the species.

  18. Link Analysis

    Science.gov (United States)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  19. Effects of the activities of key enzymes involved in starch biosynthesis on the fine structure of amylopectin in developing rice (Oryza sativa L.) endosperms

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amy- lopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch bio- synthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm de- velopment, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amy- lopectin changed continually during the development of rice grains and varied between two rice culti- vars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.

  20. Effects of the activities of key enzymes involved in starch biosynthesis on the fine structure of amylopectin in developing rice (Oryza sativa L.) endosperms.

    Science.gov (United States)

    Lü, Bing; Guo, ZhiGang; Liang, JianSheng

    2008-10-01

    The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amylopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch biosynthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm development, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amylopectin changed continually during the development of rice grains and varied between two rice cultivars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.

  1. In situ histochemical localisation of alkaloids and acetogenins in the endosperm and embryonic axis of Annona macroprophyllata Donn. Sm. seeds during germination.

    Science.gov (United States)

    Brechú-Franco, A E; Laguna-Hernández, G; De la Cruz-Chacón, I; González-Esquinca, A R

    2016-02-01

    Currently, the Annonaceae family is characterised by the production of acetogenins (ACGs), and also by the biosynthesis of alkaloids, primarily benzylisoquinolines derived from tyrosine. The objective of this study was to confirm the presence of alkaloids and acetogenins in the idioblasts of the endosperm and the embryonic axis of A. macroprophyllata seeds in germination. The Dragendorff, Dittmar, Ellram, and Lugol reagents were used to test for alkaloids, and Kedde's reagent was used to determine the presence of acetogenins in fresh sections of the endosperm and embryonic axis of seeds after twelve days of germination. A positive reaction was observed for all the reagents, and the presence of alkaloids and acetogenins was confirmed in the idioblasts of the endosperm and those involved in the differentiation of the embryonic axis of the developing seedling. We concluded that the idioblasts store both metabolites, acetogenins and alkaloids. Beginning at differentiation, the idioblasts of the embryonic axis simultaneously biosynthesise acetogenins and alkaloids that are characteristic of the species during the development of the seedling. The method used here can be applied to histochemically confirm the presence of acetogenins and alkaloids in tissues and structures of the plant in different stages of its life cycle.

  2. Endosperm and whole grain rye breads are characterized by low post-prandial insulin response and a beneficial blood glucose profile

    Directory of Open Access Journals (Sweden)

    Östman Elin M

    2009-09-01

    Full Text Available Abstract Background Rye products have previously been shown to induce comparatively low post-prandial insulin responses; irrespectively of their glycaemic indices (GI. However, the mechanism behind this lowered insulin demand remains unknown. An improved insulin economy might contribute to the benefits seen in epidemiological studies with whole grain diets on metabolic risk factors and weight regulation. The objective of this study was to explore the mechanism for a reduced post-prandial insulin demand with rye products. Methods 12 healthy subjects were given flour based rye products made from endosperm, whole grain or bran, produced with different methods (baking, simulated sour-dough baking and boiling as breakfasts in random order in a cross-over design. White wheat bread (WWB was used as a reference. Blood glucose, serum insulin, plasma ghrelin and subjective satiety were measured during 180 minutes. To evaluate the course of post-meal glycaemia, a measure of the glycaemic profile (GP was introduced defined as the duration for the incremental post-prandial blood glucose response divided with the blood glucose incremental peak (min/mM. Results The study shows that whole grain rye breads and endosperm rye products induced significantly (p Conclusion Our study shows that endosperm and wholegrain rye products induce low acute insulinaemic responses and improved glycaemic profiles. The results also suggest that the rye products possess beneficial appetite regulating properties. Further studies are needed to identify the unknown property or bioactive component(s responsible for these beneficial metabolic features of rye.

  3. Effect of high temperature on grain filling period, yield, amylose content and activity of starch biosynthesis enzymes in endosperm of basmati rice.

    Science.gov (United States)

    Ahmed, Nisar; Tetlow, Ian J; Nawaz, Sehar; Iqbal, Ahsan; Mubin, Muhammad; Nawaz ul Rehman, Muhammad Shah; Butt, Aisha; Lightfoot, David A; Maekawa, Masahiko

    2015-08-30

    High temperature during grain filling affects yield, starch amylose content and activity of starch biosynthesis enzymes in basmati rice. To investigate the physiological mechanisms underpinning the effects of high temperature on rice grain, basmati rice was grown under two temperature conditions - 32 and 22 °C - during grain filling. High temperature decreased the grain filling period from 32 to 26 days, reducing yield by 6%, and caused a reduction in total starch (3.1%) and amylose content (22%). Measurable activities of key enzymes involved in sucrose to starch conversion, sucrose synthase, ADP-glucose pyrophosphorylase, starch phosphorylase and soluble starch synthase in endosperms developed at 32 °C were lower than those at 22 °C compared with similar ripening stage on an endosperm basis. In particular, granule-bound starch synthase (GBSS) activity was significantly lower than corresponding activity in endosperms developing at 22 °C during all developmental stages analyzed. Results suggest changes in amylose/amylopectin ratio observed in plants grown at 32 °C was attributable to a reduction in activity of GBSS, the sole enzyme responsible for amylose biosynthesis. © 2014 Society of Chemical Industry.

  4. Characterization of the microchemical structure of seed endosperm within a cellular dimension among six barley varieties with distinct degradation kinetics, using ultraspatially resolved synchrotron-based infrared microspectroscopy.

    Science.gov (United States)

    Liu, Na; Yu, Peiqiang

    2010-07-14

    Barley varieties have similar chemical composition but exhibit different rumen degradation kinetics and nutrient availability. These biological differences may be related to molecular, structural, and chemical makeup among the seed endosperm tissue. No detailed study was carried out. The objectives of this study were: (1) to use a molecular spectroscopy technique, synchrotron-based Fourier transform infrared microspectroscopy (SFTIRM), to determine the microchemical-structural features in seed endosperm tissue of six developed barley varieties; (2) to study the relationship among molecular-structural characteristics, degradation kinetics, and nutrient availability in six genotypes of barley. The results showed that inherent microchemical-structural differences in the endosperm among the six barley varieties were detected by the synchrotron-based analytical technique, SFTIRM, with the univariate molecular spectral analysis. The SFTIRM spectral profiles differed (P degradation). Weak correlations may indicate that limited variations of these six barley varieties might not be sufficient to interpret the relationship between spectroscopic information and the nutrient value of barley grain, although significant differences in biodegradation kinetics were observed. In conclusion, the studies demonstrated the potential of ultraspatially resolved synchrotron based technology (SFTIRM) to reveal the structural and chemical makeup within cellular and subcellular dimensions without destruction of the inherent structure of cereal grain tissue.

  5. In situ histochemical localisation of alkaloids and acetogenins in the endosperm and embryonic axis of Annona macroprophyllata Donn. Sm. seeds during germination

    Directory of Open Access Journals (Sweden)

    A.E. Brechú-Franco

    2016-02-01

    Full Text Available Currently, the Annonaceae family is characterised by the production of acetogenins (ACGs, and also by the biosynthesis of alkaloids, primarily benzylisoquinolines derived from tyrosine. The objective of this study was to confirm the presence of alkaloids and acetogenins in the idioblasts of the endosperm and the embryonic axis of A. macroprophyllata seeds in germination. The Dragendorff, Dittmar, Ellram, and Lugol reagents were used to test for alkaloids, and Kedde’s reagent was used to determine the presence of acetogenins in fresh sections of the endosperm and embryonic axis of seeds after twelve days of germination. A positive reaction was observed for all the reagents, and the presence of alkaloids and acetogenins was confirmed in the idioblasts of the endosperm and those involved in the differentiation of the embryonic axis of the developing seedling. We concluded that the idioblasts store both metabolites, acetogenins and alkaloids. Beginning at differentiation, the idioblasts of the embryonic axis simultaneously biosynthesise acetogenins and alkaloids that are characteristic of the species during the development of the seedling. The method used here can be applied to histochemically confirm the presence of acetogenins and alkaloids in tissues and structures of the plant in different stages of its life cycle.

  6. The detection of QTLs in barley associated with endosperm hardness, grain density, grain size and malting quality using rapid phenotyping tools.

    Science.gov (United States)

    Walker, Cassandra K; Ford, Rebecca; Muñoz-Amatriaín, María; Panozzo, Joe F

    2013-10-01

    Using a barley mapping population, 'Vlamingh' × 'Buloke' (V × B), whole grain analyses were undertaken for physical seed traits and malting quality. Grain density and size were predicted by digital image analysis (DIA), while malt extract and protein content were predicted using near infrared (NIR) analysis. Validation of DIA and NIR algorithms confirmed that data for QTL analysis was highly correlated (R (2) > 0.82), with high RPD values (the ratio of the standard error of prediction to the standard deviation, 2.31-9.06). Endosperm hardness was measured on this mapping population using the single kernel characterisation system. Grain density and endosperm hardness were significantly inter-correlated in all three environments (r > 0.22, P hardness QTLs were found on 1H, 5H, and 7H. In this study, the majority of the genomic regions associated with grain texture were also coincident with QTLs for grain size, yield, flowering date and/or plant development genes. This study highlights the complexity of genomic regions associated with the variation of endosperm hardness and grain density, and their relationships with grain size traits, agronomic-related traits, and plant development loci.

  7. Effects of the activities of key enzymes involved in starch biosynthesis on the fine structure of amylopectin in developing rice (Oryza sativa L.) endosperms

    Institute of Scientific and Technical Information of China (English)

    L(U) Bing; GUO ZhiGang; LIANG JianSheng

    2008-01-01

    The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amy-Iopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch bio-synthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm de-velopment, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amy-Iopectin changed continually during the development of rice grains and varied between two rice culti-vars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.

  8. Investigating the implications of meteorological indicators of seasonal rainfall performance on maize yield in a rain-fed agricultural system: case study of Mt. Darwin District in Zimbabwe

    Science.gov (United States)

    Mushore, Terence; Manatsa, Desmond; Pedzisai, Ezra; Muzenda-Mudavanhu, Chipo; Mushore, Washington; Kudzotsa, Innocent

    2017-08-01

    The study focuses on the impacts of climate variability and change on maize yield in Mt. Darwin District. The rainfall and temperature data for the period under study that is from 1992 to 2012 were obtained from Meteorological Services Department of Zimbabwe at daily resolution while crop yield data were obtained from Department of Agricultural, Technical and Extension Services (AGRITEX) and Zimbabwe Statistics Agency (ZIMSTAT) at seasonal/yearly resolution. In order to capture full rainfall seasons, a year was set to begin on 1 June and end on 31 July the next year. Yearly yield, temperature and rainfall data were used to compute time series analysis of rainfall, temperature and yield. The relationship between temperature, rainfall, quality of season (start, cessation, dry days, wet days and length) and yield was also investigated. The study also investigated the link between meteorological normal and maize yield. The study revealed that temperature is rising while rainfall is decreasing with time hence increasing risk of low maize yield in Mt. Darwin. Correlation between maize yield was higher using a non-linear ( R 2 = 0.630) than a linear regression model ( R 2 = 0.173). There was a very high correlation between maize yield and number of dry days ( R = -0.905) as well as between maize yield and length of season ( R = 0.777). We also observed a strong correlation between percentage normal rainfall and percentage normal maize yield ( R 2 = 0.753). This was also agreed between rainfall tessiles and maize yield tessiles as 50 % of the seasons had normal and above normal rainfall coinciding with normal and above normal maize yield. Of the 21 seasons considered, only one season had above normal rainfall while maize yield was below normal. The study concluded that there is a strong association between meteorological normal and maize yield in a rain-fed agricultural system. Climate information remains crucial to agricultural productivity hence the need to train farmers

  9. Investigating the implications of meteorological indicators of seasonal rainfall performance on maize yield in a rain-fed agricultural system: case study of Mt. Darwin District in Zimbabwe

    Science.gov (United States)

    Mushore, Terence; Manatsa, Desmond; Pedzisai, Ezra; Muzenda-Mudavanhu, Chipo; Mushore, Washington; Kudzotsa, Innocent

    2016-06-01

    The study focuses on the impacts of climate variability and change on maize yield in Mt. Darwin District. The rainfall and temperature data for the period under study that is from 1992 to 2012 were obtained from Meteorological Services Department of Zimbabwe at daily resolution while crop yield data were obtained from Department of Agricultural, Technical and Extension Services (AGRITEX) and Zimbabwe Statistics Agency (ZIMSTAT) at seasonal/yearly resolution. In order to capture full rainfall seasons, a year was set to begin on 1 June and end on 31 July the next year. Yearly yield, temperature and rainfall data were used to compute time series analysis of rainfall, temperature and yield. The relationship between temperature, rainfall, quality of season (start, cessation, dry days, wet days and length) and yield was also investigated. The study also investigated the link between meteorological normal and maize yield. The study revealed that temperature is rising while rainfall is decreasing with time hence increasing risk of low maize yield in Mt. Darwin. Correlation between maize yield was higher using a non-linear (R 2 = 0.630) than a linear regression model (R 2 = 0.173). There was a very high correlation between maize yield and number of dry days (R = -0.905) as well as between maize yield and length of season (R = 0.777). We also observed a strong correlation between percentage normal rainfall and percentage normal maize yield (R 2 = 0.753). This was also agreed between rainfall tessiles and maize yield tessiles as 50 % of the seasons had normal and above normal rainfall coinciding with normal and above normal maize yield. Of the 21 seasons considered, only one season had above normal rainfall while maize yield was below normal. The study concluded that there is a strong association between meteorological normal and maize yield in a rain-fed agricultural system. Climate information remains crucial to agricultural productivity hence the need to train farmers to

  10. Cell Wall Diversity in Forage Maize

    NARCIS (Netherlands)

    Torres, A.F.; Noordam-Boot, C.M.M.; Dolstra, Oene; Weijde, van der Tim; Combes, Eliette; Dufour, Philippe; Vlaswinkel, Louis; Visser, R.G.F.; Trindade, L.M.

    2015-01-01

    Genetic studies are ideal platforms for assessing the extent of genetic diversity, inferring the genetic architecture, and evaluating complex trait interrelations for cell wall compositional and bioconversion traits relevant to bioenergy applications. Through the characterization of a forage maiz

  11. The transcriptome landscape of early maize meiosis

    Science.gov (United States)

    Meiosis, particularly meiotic recombination, is a major factor affecting yield and breeding of plants. To gain insight into the transcriptome landscape during early initiation steps of meiotic recombination, we profiled early prophase I meiocytes from maize using RNA-seq. Our analyses of genes prefe...

  12. Estimation of leaf area in tropical maize

    NARCIS (Netherlands)

    Elings, A.

    2000-01-01

    Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf nu

  13. Synthesis and Functions of Jasmonates in Maize

    Directory of Open Access Journals (Sweden)

    Eli J. Borrego

    2016-11-01

    Full Text Available Of the over 600 oxylipins present in all plants, the phytohormone jasmonic acid (JA remains the best understood in terms of its biosynthesis, function and signaling. Much like their eicosanoid analogues in mammalian system, evidence is growing for the role of the other oxylipins in diverse physiological processes. JA serves as the model plant oxylipin species and regulates defense and development. For several decades, the biology of JA has been characterized in a few dicot species, yet the function of JA in monocots has only recently begun to be elucidated. In this work, the synthesis and function of JA in maize is presented from the perspective of oxylipin biology. The maize genes responsible for catalyzing the reactions in the JA biosynthesis are clarified and described. Recent studies into the function of JA in maize defense against insect herbivory, pathogens and its role in growth and development are highlighted. Additionally, a list of JA-responsive genes is presented for use as biological markers for improving future investigations into JA signaling in maize.

  14. Can Transgenic Maize Affect Soil Microbial Communities?

    NARCIS (Netherlands)

    Mulder, Christian; Wouterse, Marja; Raubuch, Markus; Roelofs, Willem; Rutgers, Michiel

    2006-01-01

    The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical gu

  15. Exploring Identity-By-Descent Segments and Putative Functions Using Different Foundation Parents in Maize

    Science.gov (United States)

    Wu, Xun; Li, Yongxiang; Fu, Junjie; Li, Xin; Li, Chunhui; Zhang, Dengfeng; Shi, Yunsu; Song, Yanchun; Li, Yu; Wang, Tianyu

    2016-01-01

    Maize foundation parents (FPs) play no-alternative roles in hybrid breeding because they were widely used in the development of new lines and hybrids. The combination of different identity-by-descent (IBD) segments and genes could account for the formation patterns of different FPs, and knowledge of these IBD regions would provide an extensive foundation for the development of new candidate FP lines in future maize breeding. In this paper, a panel of 304 elite lines derived from FPs, i.e., B73, 207, Mo17, and Huangzaosi (HZS), was collected and analyzed using 43,252 single nucleotide polymorphism (SNP) markers. Most IBD segments specific to particular FP groups were identified, including 116 IBD segments in B73, 105 in Mo17, 111 in 207, and 190 in HZS. In these regions, 423 quantitative trait nucleotides (QTNs) associated with 15 agronomic traits and 804 candidate genes were identified. Some known adaptation-related genes, e.g., dwarf8 and vgt1 in HZS, zcn8 and epc in Mo17, and ZmCCT in 207, were validated as being tightly linked to particular IBD segments. In addition, numerous new candidate genes were also identified. For example, GRMZM2G154278 in HZS, which belongs to the cell cycle control family, was closely linked to a QTN of the ear height/plant height (EH/PH) trait; GRMZM2G051943 in 207, which encodes an endochitinase precursor (EP) chitinase, was closely linked to a QTN for kernel density; and GRMZM2G170586 in Mo17 was closely linked to a QTN for ear diameter. Complex correlations among these genes were also found. Many IBD segments and genes were included in the formation of FP lines, and complex regulatory networks exist among them. These results provide new insights on the genetic basis of complex traits and provide new candidate IBD regions or genes for the improvement of special traits in maize production. PMID:27997600

  16. Genetic Diversity and Molecular Evolution of Chinese Waxy Maize Germplasm

    Science.gov (United States)

    Zheng, Hongjian; Wang, Hui; Yang, Hua; Wu, Jinhong; Shi, Biao; Cai, Run; Xu, Yunbi; Wu, Aizhong; Luo, Lijun

    2013-01-01

    Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection. PMID:23818949

  17. Genetic diversity and molecular evolution of Chinese waxy maize germplasm.

    Directory of Open Access Journals (Sweden)

    Hongjian Zheng

    Full Text Available Waxy maize (Zea mays L. var. certaina Kulesh, with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima's D and Fu and Li's F* were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection.

  18. Effect of organic fertilizers on maize production in Eastern Georgia

    Science.gov (United States)

    Jolokhava, Tamar; Kenchiashvili, Naira; Tarkhnishvili, Maia; Ghambashidze, Giorgi

    2016-04-01

    Maize remains to be the most important cereal crop in Georgia. Total area of arable land under cereal crops production equals to 184 thousands hectares (FAO statistical yearbook, 2014), from which maize takes the biggest share. Leading position of maize among other cereal crops is caused by its dual purpose as food and feed product. In Spite of a relatively high production of maize to other cereals there is still a high demand on it, especially as feed for animal husbandry. The same tendency is seen in organic production, where producers of livestock and poultry products require organically grown maize, the average yield of which is much less than those produced conventionally. Therefore, it is important to increase productivity of maize in organic farms. Current study aimed to improve maize yield using locally produced organic fertilizers and to compare them to the effect of mineral fertilizers. The study was carried out in Eastern Georgia under dry subtropical climate conditions on local hybrid of maize. This is the first attempt to use hybrid maize (developed with organic plant breeding method) in organic field trials in Georgia. The results shown, that grain yield from two different types of organic fertilizers reached 70% of the yields achieved with industrial mineral fertilizers. As on farm level differences between organic and conventional maize production are much severe, the results from the field trials seems to be promising for future improvement of organic cereal crop production.

  19. Ontogeny of the Maize Shoot Apical Meristem[W][OA

    Science.gov (United States)

    Takacs, Elizabeth M.; Li, Jie; Du, Chuanlong; Ponnala, Lalit; Janick-Buckner, Diane; Yu, Jianming; Muehlbauer, Gary J.; Schnable, Patrick S.; Timmermans, Marja C.P.; Sun, Qi; Nettleton, Dan; Scanlon, Michael J.

    2012-01-01

    The maize (Zea mays) shoot apical meristem (SAM) arises early in embryogenesis and functions during stem cell maintenance and organogenesis to generate all the aboveground organs of the plant. Despite its integral role in maize shoot development, little is known about the molecular mechanisms of SAM initiation. Laser microdissection of apical domains from developing maize embryos and seedlings was combined with RNA sequencing for transcriptomic analyses of SAM ontogeny. Molecular markers of key events during maize embryogenesis are described, and comprehensive transcriptional data from six stages in maize shoot development are generated. Transcriptomic profiling before and after SAM initiation indicates that organogenesis precedes stem cell maintenance in maize; analyses of the first three lateral organs elaborated from maize embryos provides insight into their homology and to the identity of the single maize cotyledon. Compared with the newly initiated SAM, the mature SAM is enriched for transcripts that function in transcriptional regulation, hormonal signaling, and transport. Comparisons of shoot meristems initiating juvenile leaves, adult leaves, and husk leaves illustrate differences in phase-specific (juvenile versus adult) and meristem-specific (SAM versus lateral meristem) transcript accumulation during maize shoot development. This study provides insight into the molecular genetics of SAM initiation and function in maize. PMID:22911570

  20. Comparison of fumonisin contamination using HPLC and ELISA methods in Bt and near-isogenic maize hybrids infested with European corn borer or Western bean cutworm

    Science.gov (United States)

    Field trials were conducted (2007 to 2010) to compare grain fumonisin levels among non-Bt maize hybrids and Bt hybrids with transgenic protection against European corn borer and Western bean cutworm (WBC). High-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) w...

  1. Mitigation of aflatoxin contamination in maize kernels is related to the metabolic alternation of reactive oxygen and nitrogen species by relative humidity

    Science.gov (United States)

    Environmental factors have been shown to be linked to exacerbated infection of maize kernels by Aspergillus flavus and subsequent aflatoxin contamination. Kernel resistance to aflatoxin contamination is associated with kernel water content and relative humidity during in vitro assays examining aflat...

  2. The 50th Annual Maize Genetics Conference

    Energy Technology Data Exchange (ETDEWEB)

    Cone, Karen

    2014-03-26

    The 50th Annual Maize Genetics Conference was held February 27 - March 2, 2008 at the Marriott Wardman Park Hotel in Washington, D.C. As the golden anniversary of the Conference and coinciding with the release of a draft of the maize genome sequence, this was a special meeting. To publicize this unique occasion, meeting organizers hosted a press conference, which was attended by members of the press representing science and non-science publications, and an evening reception at the Smithsonian National Museum of Natural History, where the draft sequence was announced and awards were presented to Dr. Mary Clutter and Senator Kit Bond to thank them for their outstanding contributions to maize genetics and genomics research. As usual, the Conference provided an invigorating forum for exchange of recent research results in many areas of maize genetics, e.g., cytogenetics, development, molecular genetics, transposable element biology, biochemical genetics, and genomics. Results were shared via both oral and poster presentations. Invited talks were given by four distinguished geneticists: Vicki Chandler, University of Arizona; John Doebley, University of Wisconsin; Susan Wessler, University of Georgia; and Richard Wilson, Washington University. There were 46 short talks and 241 poster presentations. The Conference was attended by over 500 participants. This included a large number of first-time participants in the meeting and an increasingly visible presence by individuals from underrepresented groups. Although we do not have concrete counts, there seem to be more African American, African and Hispanic/Latino attendees coming to the meeting than in years past. In addition, this meeting attracted many participants from outside the U.S. Student participation continues to be hallmark of the spirit of free exchange and cooperation characteristic of the maize genetics community. With the generous support provided by DOE, USDA NSF, and corporate/private donors, organizers were

  3. Types of Maize Virus Diseases and Progress in Virus Identification Techniques in China

    Institute of Scientific and Technical Information of China (English)

    Cui Yu; Zhang Ai-hong; Ren Ai-jun; Miao Hong-qin

    2014-01-01

    There are a total of more than 40 reported maize viral diseases worldwide. Five of them have reportedly occurred in China. They are maize rough dwarf disease, maize dwarf mosaic disease, maize streak dwarf disease, maize crimson leaf disease, maize wallaby ear disease and corn lethal necrosis disease. This paper reviewed their occurrence and distribution as well as virus identification techniques in order to provide a basis for virus identification and diagnosis in corn production.

  4. Comprehending smallholder maize enterprises’ profitability with the current maize marketing system in Zimbabwe: A case of Mazowe district

    Directory of Open Access Journals (Sweden)

    John Basera

    2016-06-01

    Full Text Available Maize enterprise profitability is essential for sustainable maize production in smallholder farming. In Zimbabwe a lot of factors including several policy measures implemented in the past are believed to be influencing current maize profitability trends. Literature to confirm some of the crucial factors is limited especially in the smallholder farming sector. In this study we analyze profitability of smallholder maize farmers in Mazowe District of Zimbabwe. We estimate maize enterprise profitability using gross margin analysis, factors driving profitability using linear regression analysis and the influence of tobacco farming adoption on maize enterprise profitability using propensity score matching. We relied on both primary and secondary data from the study area. Results did not show robust outcomes on maize enterprises profitability. Maize profitability was found to be influenced positively by age of household head and selling produce to private buyers and negatively by fertilizer, chemical, and transport costs. Tobacco farming adoption was found to have a positive influence on maize profitability. Based on the results the study recommends the government through its various programs targeting agricultural development and food security to focus on smallholder maize production and marketing with the aim of improving its profitability.

  5. A cascade of sequentially expressed sucrose transporters in the seed coat and endosperm provides nutrition for the Arabidopsis embryo.

    Science.gov (United States)

    Chen, Li-Qing; Lin, I Winnie; Qu, Xiao-Qing; Sosso, Davide; McFarlane, Heather E; Londoño, Alejandra; Samuels, A Lacey; Frommer, Wolf B

    2015-03-01

    Developing plant embryos depend on nutrition from maternal tissues via the seed coat and endosperm, but the mechanisms that supply nutrients to plant embryos have remained elusive. Sucrose, the major transport form of carbohydrate in plants, is delivered via the phloem to the maternal seed coat and then secreted from the seed coat to feed the embryo. Here, we show that seed filling in Arabidopsis thaliana requires the three sucrose transporters SWEET11, 12, and 15. SWEET11, 12, and 15 exhibit specific spatiotemporal expression patterns in developing seeds, but only a sweet11;12;15 triple mutant showed severe seed defects, which include retarded embryo development, reduced seed weight, and reduced starch and lipid content, causing a "wrinkled" seed phenotype. In sweet11;12;15 triple mutants, starch accumulated in the seed coat but not the embryo, implicating SWEET-mediated sucrose efflux in the transfer of sugars from seed coat to embryo. This cascade of sequentially expressed SWEETs provides the feeding pathway for the plant embryo, an important feature for yield potential. © 2015 American Society of Plant Biologists. All rights reserved.

  6. The nutritional property of endosperm starch and its contribution to the health benefits of whole grain foods.

    Science.gov (United States)

    Zhang, Genyi; Hamaker, Bruce R

    2017-12-12

    Purported health benefits of whole grain foods in lowering risk of obesity, type 2 diabetes, cardiovascular disease, and cancer are supported by epidemiological studies and scientific researches. Bioactive components including dietary fibers, phytochemicals, and various micronutrients present in the bran and germ are commonly considered as the basis for such benefits. Endosperm starch, as the major constituent of whole grains providing glucose to the body, has been less investigated regarding its nutritional property and contribution to the value of whole grain foods. Nutritional quality of starch is associated with its rate of digestion and glucose absorption. In whole grain foods, starch digestion and glucose delivery may vary depending on the form in which the food is delivered, some with starch being rapidly and others slowly digested. Furthermore, there are other inherent factors in whole grain products, such as phenolic compounds and dietary fibers, that may moderate glycemic profiles. A good understanding of the nutritional properties of whole grain starch is important to the development of food processing technologies to maximize their health benefits.

  7. In vitro fermentation characteristics of novel fibers, coconut endosperm fiber and chicory pulp, using canine fecal inoculum.

    Science.gov (United States)

    de Godoy, M R C; Mitsuhashi, Y; Bauer, L L; Fahey, G C; Buff, P R; Swanson, K S

    2015-01-01

    The objective of this experiment was to determine the effects of in vitro fermentation of coconut endosperm fiber (CEF), chicory pulp (CHP), and selective blends of these substrates on SCFA production and changes in microbiota using canine fecal inocula. A total of 6 individual substrates, including short-chain fructooligosaccharide (scFOS; a well-established prebiotic source), pectin (PEC; used as a positive control), pelletized cellulose (PC; used as a negative control), beet pulp (BP; considered the gold standard fiber source in pet foods), CEF, and CHP, and 3 CEF:CHP blends (75:25% CEF:CHP [B1], 50:50% CEF:CHP [B2], and 25:75% CEF:CHP [B3]) were tested. Triplicate samples of each substrate were fermented for 0, 8, and 16 h after inoculation. A significant substrate × time interaction (P fiber substrates. Future research should investigate the effects of CEF, CHP, and their blends on gastrointestinal health and fecal quality in dogs.

  8. Effect of Substituting Yellow Maize for Sorghum on Broiler Performance

    Directory of Open Access Journals (Sweden)

    Mohammed A. Ahmed

    2013-03-01

    Full Text Available An experiment was conducted to study the nutritional value of yellow maize when it substitutes sorghum grain as source of energy at levels 0, 25, 50, 75 and 100% in broiler rations. One hundred and forty unsexed one day old (Ross broiler chicks were randomly assigned to five approximately isocaloric and isonitrogenous diets labeled as follows: Diet (S0 containing sorghum 100% (control, 60% of the diet, diet (S1 75% sorghum 25% maize, diet (S2 50% sorghum 50% maize, diet (S3 25% sorghum 75% maize and diet (S4 maize (100% (without sorghum. Each treatment had four replicates with 7 birds/replicate. The experiment lasted for 6 weeks. Feed intake and body weight gain had been recorded weekly. The results showed significant increase (P 0.05 effect on cold carcass dressing percentage, liver and abdominal fat weights, serum cholesterol, serum calcium and inorganic phosphorus levels. The cost of production decreased by increasing level of maize.

  9. STRATEGY OF MAIZE'S CONCENTRATING TO ADVANTAGE AREAS IN JILIN PROVINCE

    Institute of Scientific and Technical Information of China (English)

    JIANG Hui-ming; GU Li-li

    2003-01-01

    Jilin Province is one of the main grain-producing provinces of China, which has dominant position in maize production, by the view of its advantages in policy, location, breed and market. And after entering WTO,some measures have been taken to enhance maize competitive ability. But there are some difficulties in concentrating production to maize advantaged areas. This paper expounds the basis that Jilin Province becomes the advantage area of maize, analyzes the problems and puts forward the supporting policy. Some strategic measures are proposed,as developing comparable advantages, carrying out the strategy of un-equilibrium development and cultivating advantaged product areas of maize to rapidly improve the international competitive ability and productivity of maize in Jilin Province, cast the agricultural predicament off and promote the agricultural development into a new stage.

  10. [Maize seed identification using hyperspectral imaging and SVDD algorithm].

    Science.gov (United States)

    Zhu, Qi-Bing; Feng, Zhao-Li; Huang, Min; Zhu, Xiao

    2013-02-01

    The sufficiency of feature extraction and the rationality of classifier design are two key issues affecting the accuracy of maize seed recognition. In the present study, the hyperspectral images of maize seeds were acquired using hyperspectral image system, and the image entropy of maize seeds for each wavelength was extracted as classification features. Then, support vector data description (SVDD) algorithm was used to develop the classifier model for each variety of maize seeds. The SVDD models yielded 94.14% average test accuracy for known variety samples and 92.28% average test accuracy for new variety samples, respectively. The simulation results showed that the proposed method implemented accurate identification of maize seeds and solved the problem of misclassification by the traditional classification algorithm for new variety maize seeds.

  11. Characterization of factors underlying the metabolic shifts in developing kernels of colored maize

    Science.gov (United States)

    Hu, Chaoyang; Li, Quanlin; Shen, Xuefang; Quan, Sheng; Lin, Hong; Duan, Lei; Wang, Yifa; Luo, Qian; Qu, Guorun; Han, Qing; Lu, Yuan; Zhang, Dabing; Yuan, Zheng; Shi, Jianxin

    2016-01-01

    Elucidation of the metabolic pathways determining pigmentation and their underlying regulatory mechanisms in maize kernels is of high importance in attempts to improve the nutritional composition of our food. In this study, we compared dynamics in the transcriptome and metabolome between colored SW93 and white SW48 by integrating RNA-Seq and non-targeted metabolomics. Our data revealed that expression of enzyme coding genes and levels of primary metabolites decreased gradually from 11 to 21 DAP, corresponding well with the physiological change of developing maize kernels from differentiation through reserve accumulation to maturation, which was cultivar independent. A remarkable up-regulation of anthocyanin and phlobaphene pathway distinguished SW93 from SW48, in which anthocyanin regulating transcriptional factors (R1 and C1), enzyme encoding genes involved in both pathways and corresponding metabolic intermediates were up-regulated concurrently in SW93 but not in SW48. The shift from the shikimate pathway of primary metabolism to the flavonoid pathway of secondary metabolism, however, appears to be under posttranscriptional regulation. This study revealed the link between primary metabolism and kernel coloration, which facilitate further study to explore fundamental questions regarding the evolution of seed metabolic capabilities as well as their potential applications in maize improvement regarding both staple and functional foods. PMID:27739524

  12. Changes in Cinnamic Acid Derivatives Associated with the Habituation of Maize Cells to Dichlobenil

    Institute of Scientific and Technical Information of China (English)

    Hugo Mélida; Jesús .(A)lvarez; José Luis Acebes; Antonio Encina; Stephen C. Fry

    2011-01-01

    The habituation of cell cultures to cellulose biosynthesis inhibitors such as dichlobenil (DCB) represents a valuable tool to improve our knowledge of the mechanisms involved in plant cell wall structural plasticity.Maize cell lines habituated to lethal concentrations of DCB were able to grow through the acquisition of a modified cell wall in which cellulose was partially replaced by a more extensive network of arabinoxylans.The aim of this work was to investigate the phenolic metabolism of non-habituated and DCB-habituated maize cell cultures.Maize cell cultures were fed [14C]cinnamate and the fate of the radioactivity in different intra-protoplasmic and wall-localized fractions throughout the culture cycle was analyzed by autoradiography and scintillation counting.Non-habituated and habituated cultures did not markedly differ in their ability to uptake exogenous [14C]cinnamic acid.However,interesting differences were found in the radiolabeling of low- and high-Mr metabolites.Habituated cultures displayed a higher number and amount of radiolabeled low-Mr compounds,which could act as reserves later used for polysaccharide feruloylation.DCB-habituated cultures were highly enriched in esterified [14C]dehydrodiferulates and larger coupling products.In conclusion,an extensive and early cross-linking of hydroxycinnamates was observed in DCB-habituated cultures,probably strengthening their cellulose-deficient walls.

  13. The Genetics of Leaf Flecking in Maize and Its Relationship to Plant Defense and Disease Resistance.

    Science.gov (United States)

    Olukolu, Bode A; Bian, Yang; De Vries, Brian; Tracy, William F; Wisser, Randall J; Holland, James B; Balint-Kurti, Peter J

    2016-11-01

    Physiological leaf spotting, or flecking, is a mild-lesion phenotype observed on the leaves of several commonly used maize (Zea mays) inbred lines and has been anecdotally linked to enhanced broad-spectrum disease resistance. Flecking was assessed in the maize nested association mapping (NAM) population, comprising 4,998 recombinant inbred lines from 25 biparental families, and in an association population, comprising 279 diverse maize inbreds. Joint family linkage analysis was conducted with 7,386 markers in the NAM population. Genome-wide association tests were performed with 26.5 million single-nucleotide polymorphisms (SNPs) in the NAM population and with 246,497 SNPs in the association population, resulting in the identification of 18 and three loci associated with variation in flecking, respectively. Many of the candidate genes colocalizing with associated SNPs are similar to genes that function in plant defense response via cell wall modification, salicylic acid- and jasmonic acid-dependent pathways, redox homeostasis, stress response, and vesicle trafficking/remodeling. Significant positive correlations were found between increased flecking, stronger defense response, increased disease resistance, and increased pest resistance. A nonlinear relationship with total kernel weight also was observed whereby lines with relatively high levels of flecking had, on average, lower total kernel weight. We present evidence suggesting that mild flecking could be used as a selection criterion for breeding programs trying to incorporate broad-spectrum disease resistance. © 2016 American Society of Plant Biologists. All Rights Reserved.

  14. Resistance to Aspergillus flavus in maize and peanut: Molecular biology, breeding, environmental stress, and future perspectives

    Directory of Open Access Journals (Sweden)

    Jake C. Fountain

    2015-06-01

    Full Text Available The colonization of maize (Zea mays L. and peanut (Arachis hypogaea L. by the fungal pathogen Aspergillus flavus results in the contamination of kernels with carcinogenic mycotoxins known as aflatoxins leading to economic losses and potential health threats to humans. The regulation of aflatoxin biosynthesis in various Aspergillus spp. has been extensively studied, and has been shown to be related to oxidative stress responses. Given that environmental stresses such as drought and heat stress result in the accumulation of reactive oxygen species (ROS within host plant tissues, host-derived ROS may play an important role in cross-kingdom communication between host plants and A. flavus. Recent technological advances in plant breeding have provided the tools necessary to study and apply knowledge derived from metabolomic, proteomic, and transcriptomic studies in the context of productive breeding populations. Here, we review the current understanding of the potential roles of environmental stress, ROS, and aflatoxin in the interaction between A. flavus and its host plants, and the current status in molecular breeding and marker discovery for resistance to A. flavus colonization and aflatoxin contamination in maize and peanut. We will also propose future directions and a working model for continuing research efforts linking environmental stress tolerance and aflatoxin contamination resistance in maize and peanut.

  15. Adoption of Maize Conservation Tillage in Azuero, Panama

    OpenAIRE

    de Herrera, Adys Pereira; Sain, Gustavo

    1999-01-01

    An aggressive research and validation program launched in 1984 in Azuero, Panama, yielded a recommendation advocating zero tillage for maize production. Ten years later, maize farmers in Azuero used three land preparation methods: conventional tillage, zero tillage, and minimum tillage (an adaptation of the zero tillage technology). This study aimed to quantify the adoption of zero and minimum tillage for maize in Azuero; identify factors influencing adoption of the different land preparation...

  16. Effects of intercropping on maize stemborers and their natural enemies

    DEFF Research Database (Denmark)

    Skovgård, Henrik; Päts, Peeter

    1996-01-01

    The effects of maize-cowpea intercropping on three lepidopteran stemborers (Chilo partellus (Swinhoe) C. orichalcociliellus (Strand) and Sesamia calamistis Hampson) and their natural enemies were studied in Kenya. Oviposition was not affected by intercropping, but significantly fewer larvae...... and wandering spiders, were not augmented by intercropping, but an inverse relationship in abundance was found between these two predator groups. It is concluded that maize intercropped with cowpea has only limited potential as a method of controlling the key pests in maize....

  17. AN ECONOMETRIC MODEL OF THE SADC MAIZE SECTOR

    OpenAIRE

    Cutts, Michela; Hassan, Rashid M.

    2003-01-01

    In almost all of the Southern Africa Development Community (SADC) countries maize is cropped on a commercial basis except in Mauritius and Seychelles. Maize meal is the most important food staple in Southern and Eastern Africa. This is one of the main reason many governments in the region implement various policies to protect the maize sector. With adoption of the Uruguay Round Agreement on Agriculture (URAA) in the late 1990s, there has been a wave of market liberalization in the region. Mai...

  18. ACREAGE RESPONSE ANALYSIS OF MAIZE GROWERS IN KHYBER PAKHTUNKHWA, PAKISTAN

    Directory of Open Access Journals (Sweden)

    Bakhtawar Riaz

    2014-07-01

    Full Text Available This study was conducted to analyze the acreage response of maize with respect to price and non-price factors in Khyber Pakhtunkhwa. The time-series data for the period of 35 years (1976-2010 pertaining to, maize area, maize price, rice price, maize yield, average rainfall were collected from various published sources. Nerlovian adjustment lag model and Vector Auto Regression (VAR technique of estimation was employed for analyzing acreage response of maize. The model explained more than 90 percent of variation in the dependent variable. The expected maize price was unlikely found to be negative and statistically insignificant. The regression coefficients for lag rice price and lag maize yield also appeared insignificant. Area under maize in lagged year was found to be an important variable influencing farmer’s decision on acreage allocation. Among the short run and long run elasticities with respect to lag area that is 0.7155 and 2.5149, long run elasticity was more, signaling that acreage adjustment would normally take place in the long run. The coefficient of lag rainfall was found to be negative and significant indicating a negative relation between maize acreage and rainfall. The short run elasticity of maize area with respect to lag rainfall during the study period has been calculated at -0.0894 while the long run elasticity comes to be -0.3142, indicate its inelastic nature and little effect on the decision of farmers regarding allocation of land to maize. Small area adjustment coefficient (0.2845 revealed low rate of farmers’ area adjustment to desired level because of more institutional and technological constraints. Based upon the findings of this study it can be concluded that farmers allocate land to maize crop mainly basing on their previous allocation pattern rather than relative crop prices.

  19. Effects of maize maturity at harvest and dietary proportion of maize silage on intake and performance of growing/finishing bulls

    DEFF Research Database (Denmark)

    Zaralis, K.; Nørgaard, P.; Helander, C.

    2014-01-01

    of treatments, involving two maturity stages of maize at harvest (i.e. dough stage or dent stage) and two maize silage proportions (i.e. 100% maize silage or 50% maize and 50% grass silage). The diets were offered ad libitum as total mixed rations (TMRs) with inclusion of concentrates (i.e. rolled barley; dried...... to the higher ME (Pdough stage compared to dent stage maturity of maize at harvest tended to increase live-weight gain (P=0.06)....

  20. The Effects of Food Processing on the Archaeological Visibility of Maize: An Experimental Study of Carbonization of Lime-treated Maize Kernels

    OpenAIRE

    2013-01-01

    This paper explores the effects of maize processing on the carbonization and preservation of maize kernels in the archaeological record. The shift to processing maize with lime (known as hominy production in the Eastern Woodlands and nixtamalization in Mesoamerica) in ancient times had the effect of making maize more nutritious through increasing the availability of calcium, niacin, dietary fiber, and essential amino acids.  Less understood is how this process of cooking maize in a lime solut...

  1. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    Directory of Open Access Journals (Sweden)

    Buddhi Bahadur Achhami

    2015-12-01

    Full Text Available Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage percentage by stem borer was up to 18.11%. Length of the feeding tunnel in maize stem was significantly higher in January than July. In case of exit holes made by borer counted more than four holes per plant that were planted in the month of January. All in all, except the tunnel length measurement per plant, we observed similar pattern in other borer damage parameters such as exit whole counts and plant damage percentage within the tested varieties. Stem borer damage was not significantly affect on grain yield.

  2. Bt maize and integrated pest management--a European perspective.

    Science.gov (United States)

    Meissle, Michael; Romeis, Jörg; Bigler, Franz

    2011-09-01

    The European corn borer (Ostrinia nubilalis), the Mediterranean corn borer (Sesamia nonagrioides) and the western corn rootworm (Diabrotica virgifera virgifera) are the main arthropod pests in European maize production. Practised pest control includes chemical control, biological control and cultural control such as ploughing and crop rotation. A pest control option that is available since 1996 is maize varieties that are genetically engineered (GE) to produce insecticidal compounds. GE maize varieties available today express one or several genes from Bacillus thuringiensis (Bt) that target corn borers or corn rootworms. Incentives to growing Bt maize are simplified farm operations, high pest control efficiency, improved grain quality and ecological benefits. Limitations include the risk of resistance evolution in target pest populations, risk of secondary pest outbreaks and increased administration to comply with licence agreements. Growers willing to plant Bt maize in the European Union (EU) often face the problem that authorisation is denied. Only one Bt maize transformation event (MON810) is currently authorised for commercial cultivation, and some national authorities have banned cultivation. Spain is the only EU member state where Bt maize adoption levels are currently delivering farm income gains near full potential levels. In an integrated pest management (IPM) context, Bt maize can be regarded as a preventive (host plant resistance) or a responsive pest control measure. In any case, Bt maize is a highly specific tool that efficiently controls the main pests and allows combination with other preventive or responsive measures to solve other agricultural problems including those with secondary pests.

  3. Chemical composition and quality of sweet sorghum and maize silages

    OpenAIRE

    Zbigniew PODKÓWKA; Lucyna PODKÓWKA

    2011-01-01

    Sweet sorghum (Sorghum saccharatum) silage, maize (Zea mays) silage, and sorghum and maize (1:1) silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88%) in sorghum silage and the highest (37.45%) in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre an...

  4. Propanol in maize silage at Danish dairy farms

    DEFF Research Database (Denmark)

    Raun, Birgitte Marie Løvendahl; Kristensen, Niels Bastian

    2010-01-01

    The objective of the present study was to investigate the prevalence maize silage containing propanol, the seasonal variation in propanol content of maize silage, and correlations between propanol and other fermentation products in maize silage collected from 20 randomly selected Danish dairy farms...... farms, the maize silage had ≥5 g propanol/kg DM. The present study indicates that dairy cows in Denmark are commonly exposed to propanol and that approximately 20% of the dairy cows will have an intake in the range of 75-100 g propanol/d under common feeding conditions....

  5. Silicon Improves Maize Photosynthesis in Saline-Alkaline Soils

    OpenAIRE

    Zhiming Xie; Ri Song; Hongbo Shao; Fengbin Song; Hongwen Xu; Yan Lu

    2015-01-01

    The research aimed to determine the effects of Si application on photosynthetic characteristics of maize on saline-alkaline soil, including photosynthetic rate (P n ), stomatal conductance (g s ), transpiration rate (E), and intercellular CO2 concentration (C i ) of maize in the field with five levels (0, 45, 90, 150, and 225 kg·ha−1) of Si supplying. Experimental results showed that the values of P n , g s , and C i of maize were significantly enhanced while the values of E of maize were dra...

  6. Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

    Science.gov (United States)

    Truter, J; Van Hamburg, H; Van Den Berg, J

    2014-02-01

    The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

  7. Thermotropism by primary roots of maize

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, M.-C.; Poff, K.L. (MSU-DOE Plant Research Laboratory, East Lansing, MI (USA))

    1990-05-01

    Sensing in the roots of higher plants has long been recognized to be restricted mainly to gravitropism and thigmotropism. However, root responses to temperature gradients have not been extensively studied. We have designed experiments under controlled conditions to test if and how root direction of maize can be altered by thermal gradients perpendicular to the gravity vector. Primary roots of maize grown on agar plates exhibit positive thermotropism (curvature toward the warmer temperature) when exposed to gradients of 0.5 to 4.2{degree}C cm{sup {minus}1}. The extent of thermotropism depends on the temperature gradient and the temperature at which the root is placed within the gradient. The curvature cannot be accounted for by differential growth as a direct effect of temperature on each side of the root.

  8. Combining ability of twelve maize populations

    Directory of Open Access Journals (Sweden)

    Vacaro Elton

    2002-01-01

    Full Text Available Genetic progress depends on germplasm quality and breeding methods. Twelve maize populations and their crosses were evaluated to estimate combining ability and potential to be included as source populations in breeding programs. Plant height, point of insertion of the first ear, number of ears per plant, number of grains per ear, root and stalk lodging and grain yield were studied in two locations in Brazil, during the 1997/98 season. Genotype sum of squares was divided into general (GCA and specific (SCA combining ability. Results indicated the existence of genetic divergence for all traits analyzed, where additive effects were predominant. The high heterosis levels observed, mainly in Xanxerê, suggested the environmental influence on the manifestation of this genetic phenomenon. Populations revealed potential to be used in breeding programs; however, those more intensively submitted to selection could provide larger genetic progress, showing the importance of population improvement for the increment of the heterosis in maize.

  9. Grain yield stability of early maize genotypes

    Directory of Open Access Journals (Sweden)

    Chitra Bahadur Kunwar

    2016-12-01

    Full Text Available The objective of this study was to estimate grain yield stability of early maize genotypes. Five early maize genotypes namely Pool-17, Arun1EV, Arun-4, Arun-2 and Farmer’s variety were evaluated using Randomized Complete Block Design along with three replications at four different locations namely Rampur, Rajahar, Pakhribas and Kabre districts of Nepal during summer seasons of three consecutive years from 2010 to 2012 under farmer’s fields. Genotype and genotype × environment (GGE biplot was used to identify superior genotype for grain yield and stability pattern. The genotypes Arun-1 EV and Arun-4 were better adapted for Kabre and Pakhribas where as pool-17 for Rajahar environments. The overall findings showed that Arun-1EV was more stable followed by Arun-2 therefore these two varieties can be recommended to farmers for cultivation in both environments.

  10. Tracing transgenic maize as affected by breadmaking process and raw material for the production of a traditional maize bread, broa.

    Science.gov (United States)

    Fernandes, Telmo J R; Oliveira, M Beatriz P P; Mafra, Isabel

    2013-05-01

    Broa is a maize bread highly consumed and appreciated, especially in the north and central zones of Portugal. In the manufacturing of broa, maize flour and maize semolina might be used, besides other cereals such as wheat and rye. Considering the needs for genetically modified organism (GMO) traceability in highly processed foods, the aim of this work was to assess DNA degradation, DNA amplification and GMO quantification along breadmaking process of broa. DNA degradation was noticed by its decrease of integrity after dough baking and in all parts of bread sampling. The PCR amplification results of extracted DNA from the three distinct maize breads (broa 1, 2 and 3) showed that sequences for maize invertase gene and for events MON810 and TC1507 were easily detected with strong products. Real-time PCR revealed that quantification of GMO was feasible in the three different breads and that sampling location of baked bread might have a limited influence since the average quantitative results of both events after baking were very close to the actual values in the case of broa 1 (prepared with maize semolina). In the other two maize breads subjected to the same baking treatment, the contents of MON810 maize were considerably underestimated, leading to the conclusion that heat-processing was not the responsible parameter for that distortion, but the size of particle and mechanical processing of raw maize play also a major role in GMO quantification.

  11. The effects of a winter cover crop on Diabrotica virgifera (Coleoptera: Chrysomelidae) populations and beneficial arthropod communities in no-till maize.

    Science.gov (United States)

    Lundgren, Jonathan G; Fergen, Janet K

    2010-12-01

    The effects of an autumn-planted, spring-killed, grass cover crop (Elymus trachycaulus [Link] Gould ex Shinners) on populations of Diabrotica virgifera virgifera LeConte and its predator community were evaluated in South Dakota maize fields over two seasons. Abundance and size of D. virgifera larvae and adults and sex ratio of adults were measured in maize produced under two treatments (i.e., a winter cover crop or bare soil), as were maize root damage and the abundance and diversity of the predator communities collected on the soil surface and in the soil column. First and second instars and adults of D. virgifera were similarly abundant in the two treatments, but third instars were significantly fewer in maize planted after a winter cover crop. Larvae developed at different rates in the two treatments, and second instars were significantly smaller (head capsule width and body length) in the maize planted after a cover crop. First and third instars and adults were of similar size in the two treatments, and adult sex ratios were also similar. Although initially similar, predator populations increased steadily in the cover-cropped maize, which led to a significantly greater predator population by the time D. virgifera pupated. There was significantly less root damage in the cover-cropped maize. Predator communities were similarly diverse in both treatments. Predator abundance per plot was significantly and negatively correlated with the abundance of third instars per plot. Clearly, winter cover crops reduce D. virgifera performance and their damage to the crop, and we suspect that this reduction is caused by both environmental effects of the treatment on D. virgifera size and development, and of increased predation on the third instars of the pest. Additional data on the impact of cover crops on actual predation levels, grain yield and quality, and farmer profitability, and correlations among pest performance, crop characteristics, and predator populations and

  12. Intraguild Competition of Three Noctuid Maize Pests.

    Science.gov (United States)

    Bentivenha, J P F; Baldin, E L L; Hunt, T E; Paula-Moraes, S V; Blankenship, E E

    2016-08-01

    The western bean cutworm Striacosta albicosta (Smith), the fall armyworm Spodoptera frugiperda (J. E. Smith), and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) are among the major lepidopteran pests of maize in the United States, belonging to the same guild and injuring the reproductive tissues of this crop. Here, intraguild competition of these lepidopterans on non-Bt maize was evaluated through survival analysis of each species under laboratory and field conditions. Competition scenarios were carried out in arenas containing maize silk or ear tissue, using larvae on different stadium of development. Fitness cost competition studies were conducted to examine the influence of intraguild competition and cannibalism and predation rates on larval development. The survival of S. albicosta competing with the other species was significantly lower than in intraspecific competition, even when the larvae were more developed than the competitor. For S. frugiperda, survival remained high in the different competition scenarios, except when competing in a smaller stadium with H. zea Larvae of H. zea had a high rate of cannibalism, higher survival when competing against S. albicosta than S. frugiperda, and reduced survival when the H. zea larvae were at the same development stadium or smaller than the competitors. Based on fitness cost results, the absence of a competitor for the feeding source may confer an advantage to the larval development of S. frugiperda and H. zea Our data suggest that S. frugiperda has a competitive advantage against the other species, while S. albicosta has the disadvantage in the intraguild competition on non-Bt maize.

  13. Effects of Selected Diazotrophs on Maize Growth

    Science.gov (United States)

    Kifle, Medhin H.; Laing, Mark D.

    2016-01-01

    Laboratory, greenhouse, and field experiments were conducted at the University of KwaZulu-Natal, Pietermaritzburg, South Africa in the 2010/2011 and 2011∖2012 seasons to study the effects of eight strains of diazotrophic bacteria on the growth and yield of maize. Maize seeds were treated with Bacillus megaterium (V16), Pseudomonas sp. (StB5, A3, A6, and A61), Burkholderia ambifaria (V9), Enterobacter cloacae (L1) and Pantoea ananatis (LB5), aiming to stimulate plant growth, and maintain or increase yields while reducing the need for N fertilization. All the diazotrophic bacteria increased germination of maize seed, and Pseudomonas sp. (StB5) and B. megaterium (V16) significantly increased shoot length. Pseudomonas sp. (StB5), B. megaterium (V16), E. cloacae (L1), B. ambifaria (V9), and Pseudomonas sp. (A3) very significantly increased root length and seed vigor index. Under greenhouse conditions, plants treated with diazotrophic bacteria developed more leaf chlorophyll and greater dry weight, albeit not significantly (n.s.). In a field trial in 2010/2011, application of the best five diazotrophic bacteria, with or without 33% N-fertilizer, had no significant effect on germination, grain yield, dry weight, plant height and leaf chlorophyll. In the 2011/2012 growing season, at 60 days after planting (DAP), all the diazotrophic bacteria increased plant dry weights to equal that of the fertilized control (33%N-fertilizer) (n.s.). After inoculation with the diazotrophs alone increased plant heights (n.s.), and chlorophyll contents (n.s.). With the addition of 33%N-fertilizer at planting, the diazotrophs still caused increases of chlorophyll content relative to the control with 33%N (n.s.). It may be concluded that the tested diazotrophs alone may be beneficial for use on maize growth. PMID:27713756

  14. EFFECTS OF SELECTED DIAZOTROPHS ON MAIZE GROWTH

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    Medhin Hadish Kifle

    2016-09-01

    Full Text Available Laboratory, greenhouse, and field experiments were conducted at the University of KwaZulu-Natal, Pietermaritzburg, South Africa in the 2010 2011 and 2011 2012 seasons to study the effects of eight strains of diazotrophic bacteria on the growth and yield of maize. Maize seeds were treated with Bacillus megaterium (V16, Pseudomonas sp. (StB5, A3, A6, and A61, Burkholderia ambifaria (V9, Enterobacter cloacae (L1 and Pantoea ananatis (LB5, aiming to stimulate plant growth, and maintain or increase yields while reducing the need for N fertilization. All the diazotrophic bacteria increased germination of maize seed, and Pseudomonas sp. (StB5 and B. megaterium (V16 significantly increased shoot length. Pseudomonas sp. (StB5, B. megaterium (V16, E. cloacae (L1, B. ambifaria (V9 and Pseudomonas sp. (A3 very significantly increased root length and seed vigor index. Under greenhouse conditions, plants treated with diazotrophic bacteria developed more leaf chlorophyll and greater dry weight, albeit not significantly (n.s.. In a field trial in 2010/2011, application of the best five diazotrophic bacteria, with or without 33% N-fertilizer, had no significant effect on germination, grain yield, dry weight, plant height and leaf chlorophyll. In the 2011/2012 growing season, at 60 days after planting (DAP, all the diazotrophic bacteria increased plant dry weights to equal that of the fertilized control (33%N-fertilizer(n.s.. After inoculation with the diazotrophs alone increased plant heights (n.s., and chlorophyll contents (n.s.. With the addition of 33%N-fertilizer at planting, the diazotrophs still caused increases of chlorophyll content relative to the control with 33%N (n.s.. It may be concluded that the tested diazotrophs alone may be beneficial for use on maize growth.

  15. Impact of genetic structures on haploid genome-based quantification of genetically modified DNA: theoretical considerations, experimental data in MON 810 maize kernels (Zea mays L.) and some practical applications.

    Science.gov (United States)

    Zhang, David; Corlet, Aurélie; Fouilloux, Stephane

    2008-06-01

    Real-time Polymerase Chain Reaction (PCR) based assays are widely used to estimate the content of genetically modified (GM) materials in food, feed and seed. It has been known that the genetic structures of the analyte can significantly influence the GM content expressed by the haploid genome (HG) % estimated using real-time PCR assays; this kind of influence is also understood as the impact of biological factors. The influence was first simulated at theoretical level using maize as a model. We then experimentally assessed the impact of biological factors on quantitative results, analysing by quantitative real-time PCR six maize MON 810 hybrid kernels with different genetic structures: (1) hemizygous from transgenic male parent, (2) hemizygous from transgenic female parent and (3) homozygous at the transgenic locus. The results obtained in the present study showed clear influences of biological factors on GM DNA quantification: 1% of GM materials by weight (wt) for the three genetic structures contained 0.39, 0.55 and 1.0% of GM DNA by HG respectively, from quantitative real-time PCR analyses. The relationships between GM wt% and GM HG% can be empirically established as: (1) in the case of the presence of a single GM trait: GM HG% = GM wt% x (0.5 +/- 0.167Y), where Y is the endosperm DNA content (%) in the total DNA of a maize kernel, (2) in the case of the presence of multiple GM traits: GM HG% = N x GM wt% x (0.5 +/- 0.167Y), where N is the number of GM traits (stacked or not) present in an unknown sample. This finding can be used by stakeholders related to GMO for empirical prediction from one unit of expression to another in the monitoring of seed and grain production chains. Practical equations have also been suggested for haploid copy number calculations, using hemizygous GM materials for calibration curves.

  16. Differential resistance reaction of maize genotypes to maize stem borer (Chilo partellus Swinhoe at Chitwan, Nepal

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    Ghanashyam Bhandari

    2016-12-01

    Full Text Available Maize stem borer (MSB, Chilo partellus Swinhoe, Lepidoptera: Pyralidae is one of the most important insect pest of maize in Nepal. Host plant resistance is the cost-effective, ecologically sound and stable approach to reduce damage by stem borers. Forty four maize genotypes were screened for resistance to maize stem borer at the research field of National Maize Research Program, Rampur during spring seasons (March to June of two consecutive years 2013 and 2014. The maize genotypes were evaluated in randomized complete block design with three replications and data were collected on foliar damage rating, tunnel length and number of exit holes made by the borer. The foliar damage and tunnel length damage were significant for genotypes for both the years. The exit holes were not significant in 2013 but significant in 2014 ranging from 2-6 scale. The foliar rating ranged from 2 to 5.5 in 2013 and 1.1 to 4.5 in 2014 on a 1-9 rating scale. The highly resistant genotypes (10 cm scale. The least susceptible genotypes (<5 cm were RampurSO3F8, RampurSO3FQ02 and RampurS10F18. The genotypes having least exit holes (2.0 in 2014 were RampurSO3F8, RampurSO3FQ02, RampurS10F18. Thus less damage parameters were observed in R-POP-2, RML-5/RML-8, RampurSO3F8, RampurSO3FQ02 and RampurS10F18 and therefore they can be used as parents or as sources of resistance in breeding program.

  17. Aflatoxin Accumulation in a Maize Diallel Cross

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    W. Paul Williams

    2015-06-01

    Full Text Available Aflatoxins, produced by the fungus Aspergillus flavus, occur naturally in maize. Contamination of maize grain with aflatoxin is a major food and feed safety problem and greatly reduces the value of the grain. Plant resistance is generally considered a highly desirable approach to reduction or elimination of aflatoxin in maize grain. In this investigation, a diallel cross was produced by crossing 10 inbred lines with varying degrees of resistance to aflatoxin accumulation in all possible combinations. Three lines that previously developed and released as sources of resistance to aflatoxin accumulation were included as parents. The 10 parental inbred lines and the 45 single crosses making up the diallel cross were evaluated for aflatoxin accumulation in field tests conducted in 2013 and 2014. Plants were inoculated with an A. flavus spore suspension seven days after silk emergence. Ears were harvested approximately 60 days later and concentration of aflatoxin in the grain determined. Parental inbred lines Mp717, Mp313E, and Mp719 exhibited low levels (3–12 ng/g of aflatoxin accumulation. In the diallel analysis, both general and specific combining ability were significant sources of variation in the inheritance of resistance to aflatoxin accumulation. General combining ability effects for reduced aflatoxin accumulation were greatest for Mp494, Mp719, and Mp717. These lines should be especially useful in breeding for resistance to aflatoxin accumulation. Breeding strategies, such as reciprocal recurrent selection, would be appropriate.

  18. Aflatoxin Control in Maize by Trametes versicolor

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    Marzia Scarpari

    2014-12-01

    Full Text Available Aspergillus flavus is a well-known ubiquitous fungus able to contaminate both in pre- and postharvest period different feed and food commodities. During their growth, these fungi can synthesise aflatoxins, secondary metabolites highly hazardous for animal and human health. The requirement of products with low impact on the environment and on human health, able to control aflatoxin production, has increased. In this work the effect of the basidiomycete Trametes versicolor on the aflatoxin production by A. flavus both in vitro and in maize, was investigated. The goal was to propose an environmental loyal tool for a significant control of aflatoxin production, in order to obtain feedstuffs and feed with a high standard of quality and safety to enhance the wellbeing of dairy cows. The presence of T. versicolor, grown on sugar beet pulp, inhibited the production of aflatoxin B1 in maize by A. flavus. Furthermore, treatment of contaminated maize with culture filtrates of T. versicolor containing ligninolytic enzymes, showed a significant reduction of the content of aflatoxin B1.

  19. Aflatoxin regulations in a network of global maize trade.

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    Felicia Wu

    Full Text Available Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000-2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B(1, B(2, G(1, and G(2 differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards.

  20. Aflatoxin Regulations in a Network of Global Maize Trade

    Science.gov (United States)

    Wu, Felicia; Guclu, Hasan

    2012-01-01

    Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000–2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B1, B2, G1, and G2) differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards. PMID:23049773

  1. The response of maize production in Kenya to economic incentives

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    Onono, P.A.,

    2013-06-01

    Full Text Available Agricultural development policy in Kenya has emphasised the use of incentives towards increased production and therefore self-sufficiency in maize which is a basic staple for most households. The channels used to provide incentives to maize farmers over the years include setting higher producer prices; subsidisation of inputs; provision of agricultural credit, research and extension services; construction and maintenance of roads, development of irrigation and water systems; legislative, institutional and macroeconomic reforms. Despite these efforts outputof maize has remained below domestic requirements in most years and the country continues to rely on imports to meet the deficits. Studies have assessed the responsiveness of maize to output price and reported inelastic responses and have recommended policies targeting non-price incentives to complement prices for the required increased production of maize. The studies, however, did not analyse the influence of the non-price incentives on the production of the crop. The findings of those studies are therefore deficient in explaining the relative importance of different non-price incentives and how they complement prices in influencing maize production in Kenya. This study investigated the response of maize production to both price and non-price incentives. The aim of this study was to ascertain the relative importance of non-price factors in influencing production of the crops as well as complementarity between price and non-price incentives. The findings show that maize production responds positively to its output price, development expenditures in agriculture, maize sales to marketing boards, growth in per capita GDP, liberalisation and governance reforms. However, maize production responds negatively to fertiliser price and unfavourable weather conditions. The response of maize output to its price is lower with rising inflation and grain market liberalisation.

  2. Aflatoxin regulations in a network of global maize trade.

    Science.gov (United States)

    Wu, Felicia; Guclu, Hasan

    2012-01-01

    Worldwide, food supplies often contain unavoidable contaminants, many of which adversely affect health and hence are subject to regulations of maximum tolerable levels in food. These regulations differ from nation to nation, and may affect patterns of food trade. We soughtto determine whether there is an association between nations' food safety regulations and global food trade patterns, with implications for public health and policymaking. We developed a network model of maize trade around the world. From maize import/export data for 217 nations from 2000-2009, we calculated basic statistics on volumes of trade; then examined how regulations of aflatoxin, a common contaminant of maize, are similar or different between pairs of nations engaging in significant amounts of maize trade. Globally, market segregation appears to occur among clusters of nations. The United States is at the center of one cluster; European countries make up another cluster with hardly any maize trade with the US; and Argentina, Brazil, and China export maize all over the world. Pairs of nations trading large amounts of maize have very similar aflatoxin regulations: nations with strict standards tend to trade maize with each other, while nations with more relaxed standards tend to trade maize with each other. Rarely among the top pairs of maize-trading nations do total aflatoxin standards (standards based on the sum of the levels of aflatoxins B(1), B(2), G(1), and G(2)) differ by more than 5 µg/kg. These results suggest that, globally, separate maize trading communities emerge; and nations tend to trade with other nations that have very similar food safety standards.

  3. The mycotoxin distribution in maize milling fractions under experimental conditions.

    Science.gov (United States)

    Burger, H-M; Shephard, G S; Louw, W; Rheeder, J P; Gelderblom, W C A

    2013-07-01

    Mycotoxin contamination of maize and maize-based food and feed products poses a health risk to humans and animals if not adequately controlled and managed. The current study investigates the effect of dry milling on the reduction of fumonisins (FB), deoxynivalenol (DON) and zearalenone (ZEA) in maize. Five composite samples, constructed to represent different mycotoxin contamination levels were degermed yielding degermed maize and the germ. The degermed maize was milled under laboratory conditions and four major milling fractions (SPECIAL, SUPER, semolina (SEM) and milling hominy feed) collected. The whole maize, degermed maize and total hominy feed (germ+milling hominy feed) were reconstructed to ensure homogenous samples for mycotoxin analyses. For comparison, commercial dry milling fractions (whole maize, SPECIAL, SUPER and total hominy feed), collected from three South African industrial mills, were analysed for the same mycotoxins and hence a more accurate assessment of the distribution between the different milling fractions. The distribution of the mycotoxins during the experimental dry milling of the degermed maize differs, with FB mainly concentrated in the SPECIAL, DON in the SEM whereas ZEA was equally distributed between the two milling fractions. Distribution of mycotoxins between the fractions obtained during commercial dry milling generally provided similar results with the total hominy feed containing the highest and the SUPER milling fractions the lowest mycotoxin levels although variations existed. Although milling is an effective way to reduce mycotoxins in maize, kernel characteristics and resultant fungal colonisation may impact on the distribution of specific mycotoxins among the different milling fractions. Differences in industrial dry milling practices and problems encountered in sampling bulk maize remain a large problem in assessing mycotoxin contamination in milling fractions intended for human consumption.

  4. Deficiency of maize starch-branching enzyme i results in altered starch fine structure, decreased digestibility and reduced coleoptile growth during germination

    Science.gov (United States)

    2011-01-01

    Background Two distinct starch branching enzyme (SBE) isoforms predate the divergence of monocots and dicots and have been conserved in plants since then. This strongly suggests that both SBEI and SBEII provide unique selective advantages to plants. However, no phenotype for the SBEI mutation, sbe1a, had been previously observed. To explore this incongruity the objective of the present work was to characterize functional and molecular phenotypes of both sbe1a and wild-type (Wt) in the W64A maize inbred line. Results Endosperm starch granules from the sbe1a mutant were more resistant to digestion by pancreatic α-amylase, and the sbe1a mutant starch had an altered branching pattern for amylopectin and amylose. When kernels were germinated, the sbe1a mutant was associated with shorter coleoptile length and higher residual starch content, suggesting that less efficient starch utilization may have impaired growth during germination. Conclusions The present report documents for the first time a molecular phenotype due to the absence of SBEI, and suggests strongly that it is associated with altered physiological function of the starch in vivo. We believe that these results provide a plausible rationale for the conservation of SBEI in plants in both monocots and dicots, as greater seedling vigor would provide an important survival advantage when resources are limited. PMID:21599988

  5. Deficiency of maize starch-branching enzyme i results in altered starch fine structure, decreased digestibility and reduced coleoptile growth during germination

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    Yandeau-Nelson Marna

    2011-05-01

    Full Text Available Abstract Background Two distinct starch branching enzyme (SBE isoforms predate the divergence of monocots and dicots and have been conserved in plants since then. This strongly suggests that both SBEI and SBEII provide unique selective advantages to plants. However, no phenotype for the SBEI mutation, sbe1a, had been previously observed. To explore this incongruity the objective of the present work was to characterize functional and molecular phenotypes of both sbe1a and wild-type (Wt in the W64A maize inbred line. Results Endosperm starch granules from the sbe1a mutant were more resistant to digestion by pancreatic α-amylase, and the sbe1a mutant starch had an altered branching pattern for amylopectin and amylose. When kernels were germinated, the sbe1a mutant was associated with shorter coleoptile length and higher residual starch content, suggesting that less efficient starch utilization may have impaired growth during germination. Conclusions The present report documents for the first time a molecular phenotype due to the absence of SBEI, and suggests strongly that it is associated with altered physiological function of the starch in vivo. We believe that these results provide a plausible rationale for the conservation of SBEI in plants in both monocots and dicots, as greater seedling vigor would provide an important survival advantage when resources are limited.

  6. Genome-Wide Mapping of Targets of Maize Histone Deacetylase HDA101 Reveals Its Function and Regulatory Mechanism during Seed Development[OPEN

    Science.gov (United States)

    Yang, Hua; Liu, Xinye; Xin, Mingming; Du, Jinkun; Hu, Zhaorong; Peng, HuiRu; Sun, Qixin; Ni, Zhongfu; Yao, Yingyin

    2016-01-01

    Histone deacetylases (HDACs) regulate histone acetylation levels by removing the acetyl group from lysine residues. The maize (Zea mays) HDAC HDA101 influences several aspects of development, including kernel size; however, the molecular mechanism by which HDA101 affects kernel development remains unknown. In this study, we find that HDA101 regulates the expression of transfer cell-specific genes, suggesting that their misregulation may be associated with the defects in differentiation of endosperm transfer cells and smaller kernels observed in hda101 mutants. To investigate HDA101 function during the early stages of seed development, we performed genome-wide mapping of HDA101 binding sites. We observed that, like mammalian HDACs, HDA101 mainly targets highly and intermediately expressed genes. Although loss of HDA101 can induce histone hyperacetylation of its direct targets, this often does not involve variation in transcript levels. A small subset of inactive genes that must be negatively regulated during kernel development is also targeted by HDA101 and its loss leads to hyperacetylation and increased expression of these inactive genes. Finally, we report that HDA101 interacts with members of different chromatin remodeling complexes, such as NFC103/MSI1 and SNL1/SIN3-like protein corepressors. Taken together, our results reveal a complex genetic network regulated by HDA101 during seed development and provide insight into the different mechanisms of HDA101-mediated regulation of transcriptionally active and inactive genes. PMID:26908760

  7. SSH Analysis of Endosperm Transcripts and Characterization of Heat Stress Regulated Expressed Sequence Tags in Bread Wheat.

    Science.gov (United States)

    Goswami, Suneha; Kumar, Ranjeet R; Dubey, Kavita; Singh, Jyoti P; Tiwari, Sachidanand; Kumar, Ashok; Smita, Shuchi; Mishra, Dwijesh C; Kumar, Sanjeev; Grover, Monendra; Padaria, Jasdeep C; Kala, Yugal K; Singh, Gyanendra P; Pathak, Himanshu; Chinnusamy, Viswanathan; Rai, Anil; Praveen, Shelly; Rai, Raj D

    2016-01-01

    Heat stress is one of the major problems in agriculturally important cereal crops, especially wheat. Here, we have constructed a subtracted cDNA library from the endosperm of HS-treated (42°C for 2 h) wheat cv. HD2985 by suppression subtractive hybridization (SSH). We identified ~550 recombinant clones ranging from 200 to 500 bp with an average size of 300 bp. Sanger's sequencing was performed with 205 positive clones to generate the differentially expressed sequence tags (ESTs). Most of the ESTs were observed to be localized on the long arm of chromosome 2A and associated with heat stress tolerance and metabolic pathways. Identified ESTs were BLAST search using Ensemble, TriFLD, and TIGR databases and the predicted CDS were translated and aligned with the protein sequences available in pfam and InterProScan 5 databases to predict the differentially expressed proteins (DEPs). We observed eight different types of post-translational modifications (PTMs) in the DEPs corresponds to the cloned ESTs-147 sites with phosphorylation, 21 sites with sumoylation, 237 with palmitoylation, 96 sites with S-nitrosylation, 3066 calpain cleavage sites, and 103 tyrosine nitration sites, predicted to sense the heat stress and regulate the expression of stress genes. Twelve DEPs were observed to have transmembrane helixes (TMH) in their structure, predicted to play the role of sensors of HS. Quantitative Real-Time PCR of randomly selected ESTs showed very high relative expression of HSP17 under HS; up-regulation was observed more in wheat cv. HD2985 (thermotolerant), as compared to HD2329 (thermosusceptible) during grain-filling. The abundance of transcripts was further validated through northern blot analysis. The ESTs and their corresponding DEPs can be used as molecular marker for screening or targeted precision breeding program. PTMs identified in the DEPs can be used to elucidate the thermotolerance mechanism of wheat-a novel step toward the development of "climate-smart" wheat.

  8. SSH analysis of endosperm transcripts and characterization of heat stress regulated expressed sequence tags in bread wheat

    Directory of Open Access Journals (Sweden)

    Suneha Goswami

    2016-08-01

    Full Text Available Heat stress is one of the major problems in agriculturally important cereal crops, especially wheat. Here, we have constructed a subtracted cDNA library from the endosperm of HS-treated (42°C for 2 h wheat cv. HD2985 by suppression subtractive hybridization (SSH. We identified ~550 recombinant clones ranging from 200 to 500 bp with an average size of 300 bp. Sanger’s sequencing was performed with 205 positive clones to generate the differentially expressed sequence tags (ESTs. Most of the ESTs were observed to be localized on the long arm of chromosome 2A and associated with heat stress tolerance and metabolic pathways. Identified ESTs were BLAST search using Ensemble, TriFLD and TIGR databases and the predicted CDS were translated and aligned with the protein sequences available in pfam and InterProScan 5 databases to predict the differentially expressed proteins (DEPs. We observed eight different types of post-translational modifications (PTMs in the DEPs corresponds to the cloned ESTs—147 sites with phosphorylation, 21 sites with sumoylation, 237 with palmitoylation, 96 sites with S-nitrosylation, 3066 calpain cleavage sites, and 103 tyrosine nitration sites, predicted to sense the heat stress and regulate the expression of stress genes. Twelve DEPs were observed to have transmembrane helixes (TMH in their structure, predicted to play the role of sensors of HS. Quantitative Real-Time PCR of randomly selected ESTs showed very high relative expression of HSP17 under HS; up-regulation was observed more in wheat cv. HD2985 (thermotolerant, as compared to HD2329 (thermosusceptible during grain-filling. The abundance of transcripts was further validated through northern blot analysis. The ESTs and their corresponding DEPs can be used as molecular marker for screening or targeted precision breeding program. PTMs identified in the DEPs can be used to elucidate the thermotolerance mechanism of wheat – a novel step towards the development of

  9. SSH Analysis of Endosperm Transcripts and Characterization of Heat Stress Regulated Expressed Sequence Tags in Bread Wheat

    Science.gov (United States)

    Goswami, Suneha; Kumar, Ranjeet R.; Dubey, Kavita; Singh, Jyoti P.; Tiwari, Sachidanand; Kumar, Ashok; Smita, Shuchi; Mishra, Dwijesh C.; Kumar, Sanjeev; Grover, Monendra; Padaria, Jasdeep C.; Kala, Yugal K.; Singh, Gyanendra P.; Pathak, Himanshu; Chinnusamy, Viswanathan; Rai, Anil; Praveen, Shelly; Rai, Raj D.

    2016-01-01

    Heat stress is one of the major problems in agriculturally important cereal crops, especially wheat. Here, we have constructed a subtracted cDNA library from the endosperm of HS-treated (42°C for 2 h) wheat cv. HD2985 by suppression subtractive hybridization (SSH). We identified ~550 recombinant clones ranging from 200 to 500 bp with an average size of 300 bp. Sanger's sequencing was performed with 205 positive clones to generate the differentially expressed sequence tags (ESTs). Most of the ESTs were observed to be localized on the long arm of chromosome 2A and associated with heat stress tolerance and metabolic pathways. Identified ESTs were BLAST search using Ensemble, TriFLD, and TIGR databases and the predicted CDS were translated and aligned with the protein sequences available in pfam and InterProScan 5 databases to predict the differentially expressed proteins (DEPs). We observed eight different types of post-translational modifications (PTMs) in the DEPs corresponds to the cloned ESTs-147 sites with phosphorylation, 21 sites with sumoylation, 237 with palmitoylation, 96 sites with S-nitrosylation, 3066 calpain cleavage sites, and 103 tyrosine nitration sites, predicted to sense the heat stress and regulate the expression of stress genes. Twelve DEPs were observed to have transmembrane helixes (TMH) in their structure, predicted to play the role of sensors of HS. Quantitative Real-Time PCR of randomly selected ESTs showed very high relative expression of HSP17 under HS; up-regulation was observed more in wheat cv. HD2985 (thermotolerant), as compared to HD2329 (thermosusceptible) during grain-filling. The abundance of transcripts was further validated through northern blot analysis. The ESTs and their corresponding DEPs can be used as molecular marker for screening or targeted precision breeding program. PTMs identified in the DEPs can be used to elucidate the thermotolerance mechanism of wheat—a novel step toward the development of

  10. Isolation of the endosperm-specific LPAAT gene promoter from coconut (Cocos nucifera L.) and its functional analysis in transgenic rice plants.

    Science.gov (United States)

    Xu, Li; Ye, Rongjian; Zheng, Yusheng; Wang, Zhekui; Zhou, Peng; Lin, Yongjun; Li, Dongdong

    2010-09-01

    As one of the key tropical crops, coconut (Cocos nucifera L.) is a member of the monocotyledonous family Aracaceae (Palmaceae). In this study, we amplified the upstream region of an endosperm-specific expression gene, Lysophosphatidyl acyltransferase (LPAAT), from the coconut genomic DNA by chromosome walking. In this sequence, we found several types of promoter-related elements including TATA-box, CAAT-box and Skn1-motif. In order to further examine its function, three different 5'-deletion fragments were inserted into pBI101.3, a plant expression vector harboring the LPAAT upstream sequence, leading to pBI101.3-L1, pBI101.3-L2 and pBI101.3-L3, respectively. We obtained transgenic plants of rice by Agrobacterium-mediated callus transformation and plant regeneration and detected the expression of gus gene by histochemical staining and fluorometric determination. We found that gus gene driven by the three deletion fragments was specifically expressed in the endosperm of rice seeds, but not in the empty vector of pBI101.3 and other tissues. The highest expression level of GUS was at 15 DAF in pBI101.3-L3 and pBI101.3-L2 transgenic lines, while the same level was detected at 10 DAF in pBI101.3-L1. The expression driven by the whole fragment was up to 1.76- and 2.8-fold higher than those driven by the -817 bp and -453 bp upstream fragments, and 10.7-fold higher than that driven by the vector without the promoter. Taken together, our results strongly suggest that these promoter fragments from coconut have a significant potential in genetically improving endosperm in main crops.

  11. Role of zein proteins in structure and assembly of protein bodies and endosperm texture. Progress report and appendix 1 - preliminary data

    Energy Technology Data Exchange (ETDEWEB)

    Larkins, B.

    1997-05-01

    Although funding for this project was initiated less than two years ago, we have made significant progress with our research objectives. We have cloned the gene responsible for the fl2 mutation. In fl2, the mutant phenotype appears to result from a defective signal peptide in an alpha-zein protein. As a consequence, the signal peptide remains attached when the protein accumulates in the protein body. A mutation like fl2 could explain other semidominant and dominant opaque mutants on the basis of abnormal zein polypeptides. A manuscript describing the research that led to the cloning of fl2 is in press, and a second manuscript on the characterization of this gene has been prepared for publication. We found that increased amounts of the 27-kD gamma-zein protein enlarge the proportion of vitreous endosperm and increases the hardness of o2 mutants. This protein also enhances these properties in wild type seeds. The mechanism by which the gamma-zein protein brings about these changes is unclear, and is under investigation. We have found and characterized several mutants that reduce gamma-zein synthesis. The mutations do not significantly affect synthesis of any other type of zein protein. They appear to create an opaque phenotype by reducing the number rather than the size of protein bodies. Interestingly, the mutant seeds fail to germinate. A manuscript describing one of these mutants, o15, has been prepared for publication. We have created a number of transgenic tobacco plants that can produce alpha-, beta-, gamma(27-kD)-, or delta-zeins, as well as combinations of these proteins. Analysis of seeds from these plants and crosses of these plants has shown that tobacco endosperm can serve as a heterologous system to study zein interactions. We have obtained evidence that interactions between alpha- and gamma-zein proteins are required for stable accumulation of alpha-zeins in the endosperm. These and other preliminary results are illustrated in Appendix 1.

  12. Myrigalone A inhibits Lepidium sativum seed germination by interference with gibberellin metabolism and apoplastic superoxide production required for embryo extension growth and endosperm rupture.

    Science.gov (United States)

    Oracz, Krystyna; Voegele, Antje; Tarkowská, Danuse; Jacquemoud, Dominique; Turecková, Veronika; Urbanová, Terezie; Strnad, Miroslav; Sliwinska, Elwira; Leubner-Metzger, Gerhard

    2012-01-01

    Myrica gale L. (sweet gale) fruit leachate contains myrigalone A (MyA), a rare C-methylated dihydrochalcone and putative allelochemical, which is known to be a phytotoxin impeding seedling growth. We found that MyA inhibited Lepidium sativum L. seed germination in a dose-dependent manner. MyA did not affect testa rupture, but inhibited endosperm rupture and the transition to subsequent seedling growth. MyA inhibited micropylar endosperm cap (CAP) weakening and the increase in the growth potential of the radical/hypocotyl region (RAD) of the embryo, both being key processes required for endosperm rupture. We compared the contents of abscisic acid (ABA) and gibberellins in the tissues and found that the major bioactive forms of gibberellin in L. sativum seed tissues were GA(4) and GA(6), while GA(8) and GA(13) were abundant inactive metabolites. MyA did not appreciably affect the ABA contents, but severely interfered with gibberellin metabolism and signaling by inhibiting important steps catalyzed by GA3 oxidase, as well as by interfering with the GID1-type gibberellin signaling pathway. The hormonally and developmentally regulated formation of apoplastic superoxide radicals is important for embryo growth. Specific zones within the RAD were associated with accumulation of apoplastic superoxide radicals and endoreduplication indicative of embryo cell extension. MyA negatively affected both of these processes and acted as a scavenger of apoplastic reactive oxygen species. We propose that MyA is an allelochemical with a novel mode of action on seed germination.

  13. The Effects of Food Processing on the Archaeological Visibility of Maize: An Experimental Study of Carbonization of Lime-treated Maize Kernels

    Directory of Open Access Journals (Sweden)

    Caroline Dezendorf

    2013-01-01

    Full Text Available This paper explores the effects of maize processing on the carbonization and preservation of maize kernels in the archaeological record. The shift to processing maize with lime (known as hominy production in the Eastern Woodlands and nixtamalization in Mesoamerica in ancient times had the effect of making maize more nutritious through increasing the availability of calcium, niacin, dietary fiber, and essential amino acids.  Less understood is how this process of cooking maize in a lime solution affects the archaeological preservation of maize; if there is a clear difference in the archaeological signature of maize remains that are and are not processed this way, then this process may be identifiable in the archaeological record. To this end, an experiment was constructed analyzing the variation in size between dried and alkali processed maize kernels before and after carbonization. Results indicate that alkali processed maize kernels are less likely to fragment during carbonization.

  14. Structure and Development of Endosperm Transfer Cells in Wheat%小麦胚乳传递细胞发育的结构观察

    Institute of Scientific and Technical Information of China (English)

    王慧慧; 王峰; 刘大同; 顾蕴洁; 王忠

    2011-01-01

    In developing wheat caryopsis,grain filling nutrients transport into the endosperm via endosperm transfer cells(ETCs).The developmental extent of ETCs is in close relation to yield and qualities of wheat.In this paper we investigated the developmental process and structural features of ETCs in wheat systematically by the combination of light microscopy and transmission electron microscopy.Main results were as follows:(1) ETCs occured in the endosperm epidermis bordering the endosperm cavity and were the first cell type histologically differentiated during endosperm development.ETCs could be divided into two subtypes: outer 1~2 layer of aleurone transfer cells and inner 1~2 layer of starchy endosperm transfer cells.(2) As caryopsis matured,the nuclei of starchy endosperm transfer cells disappeared,while the nuclei of aleurone transfer cells remained intact.(3) The development of ETCs showed obvious polarity and the pattern of temporal and spatial gradient.(4) Aleurone transfer cells had dense cytoplasm rich in rough endoplasmic reticulum,mitochondria,dictyosomes and lipid bodies;their plasma membrane wrinkled and in some region evaginated to form numerous plasmatubules.(5) Starchy endosperm transfer cells had sparse cytoplasm rich in amyloplasts and were highly vacuolated.(6) Lots of plasmodesmata penetrated into adjoining primary walls of ETCs where thickening and wall ingrowths didn't occur.(7) Mitochondria in ETCs showed polarized distribution,and most of them lied in the proximity of plasma membrane.The structural features of ETCs suggested that they may play a role in nutrients transportation into the endosperm both via apoplastic and symplastic pathway.%为从细胞学方面了解小麦产量和品质的形成机制,以扬麦5号为材料,利用光镜和透射电镜观察了小麦颖果发育过程中胚乳传递细胞的结构变化,并探讨了胚乳传递细胞的生理功能。结果表明:(1)胚乳传递细胞

  15. Tetrasporic Embryo-Sac Formation in Trisomic Sectors of Maize.

    Science.gov (United States)

    Neuffer, M G

    1964-05-15

    Nondisjunction in mitotic divisions occurs spontaneously at a low frequency in somatic and germinal tissue in maize and results in sectors of trisomic cells. When this happens with chromosome 3 and in germinal tissue the embryo sac development is changed from the normal monosporic type to a tetrasporic type which is common in some species but not in maize.

  16. Rapid cycling genomic selection in a multiparental tropical maize population

    Science.gov (United States)

    Genomic selection (GS) increases genetic gain by reducing the length of the selection cycle, as has been exemplified in maize using rapid cycling recombination of biparental populations. However, no results of GS applied to maize multi-parental populations have been reported so far. This study is th...

  17. Dispersal behaviour of Trichogramma brassicae in maize fields

    NARCIS (Netherlands)

    Suverkropp, B.P.; Bigler, F.; Lenteren, van J.C.

    2009-01-01

    Glue-sprayed maize plants were used to study dispersal behaviour of the egg parasitoid Trichogramma brassicae Bezdenko (Hymenoptera Trichogrammatidae) in maize fields. To estimate the distance covered during an initial flight, T. brassicae were studied in a field cage with 73 glue-sprayed plants. Mo

  18. Maize Diversification by Capturing Useful Alleles from Exotic Germplasm

    Science.gov (United States)

    Archeological, carbon-14 dating of maize specimens, and microsatellite evidence has provided strong support for domestication of maize 9,000 - 10,000 years ago from Z. mays ssp. parviglumis (Doebley, 1990) in southern Mexico (Matsuoka et. al., 2002). Since then, early and modern plant breeders...

  19. Genetic, evoluntionary and plant breedinginsights from the domestication of maize

    Science.gov (United States)

    The natural history of maize began nine thousand years ago when Mexican farmers started to collect the seeds of the wild grass, teosinte. Invaluable as a food source, maize permeated Mexican culture and religion. Its domestication eventually led to its adoption as a model organism, aided in large pa...

  20. research note disappearance of processed maize grain in the rumen

    African Journals Online (AJOL)

    (Key words: Rumen, maize-grain-form, disappearance, dacrutn hag) .... Particle size distibution of maize gain hammermilled through a 6 ... tion feeding level and sex on body cornpositi()n at two live weights. J. Agric. ... R. & (;RHENHAt-GFl, J.F.D., l9ll. ,Alkali treatment as method of processing whole grain for cattle. J. Agrit' ...

  1. Entering the second century of maize quantitative genetics

    Science.gov (United States)

    Maize is the most widely grown cereal in the world. In addition to its role in global agriculture, it has also long served as a model organism for genetic research. Maize stands at a genetic crossroads, as it has access to all the tools available for plant genetics but exhibits a genetic architectur...

  2. Chemical composition and quality of sweet sorghum and maize silages

    Directory of Open Access Journals (Sweden)

    Zbigniew PODKÓWKA

    2011-10-01

    Full Text Available Sweet sorghum (Sorghum saccharatum silage, maize (Zea mays silage, and sorghum and maize (1:1 silage were investigated. The silages were analysed for chemical composition, quality and aerobic stability. Dry matter was the lowest (20.88% in sorghum silage and the highest (37.45% in maize silage. In sorghum silage, the concentration of crude ash and crude fibre was higher, and that of crude protein, crude fat and N-free extractives lower compared to maize silage. Neutral detergent fibre and acid detergent fibre were the highest in sorghum silage and the lowest in maize silage. The silages were dominated by lactic acid, with trace amounts of butyric acid. Maize silage was higher lactic acid and higher total acids than others. All silages were of very good quality according to Flieg-Zimmer scale. Silage pH ranged from 4.20 to 4.31. Sorghum silage was characterized by higher aerobic stability (81h compared to the other silages from maize (74h and sorghum and maize 1:1 (69h.

  3. Yield advantage and water saving in maize/pea intercrop

    NARCIS (Netherlands)

    Mao, L.; Zhang, L.; Li, W.; Werf, van der W.; Sun, J.; Spiertz, J.H.J.; Li, L.

    2012-01-01

    Intercropping is a well-established strategy for maximization of yield from limited land, but mixed results have been obtained as to its performance in terms of water use efficiency. Here, two maize/pea intercrop layouts were studied in comparison to sole maize and sole pea with and without plastic

  4. Assessing maize foliar water stress levels under field conditions ...

    African Journals Online (AJOL)

    Assessing maize foliar water stress levels under field conditions using in-situ ... is non-destructive to the crops as opposed to other traditional ground-based methods. ... water indices that could monitor the water status at leaf level on maize (Zea ... about AJOL · AJOL's Partners · Contact AJOL · Terms and Conditions of Use.

  5. Exploring cost-effective maize integrated weed management ...

    African Journals Online (AJOL)

    ACSS

    management (IWM) approach in maize in eastern Uganda. ... Returns on investment (ROI) were highest under pre-Atz+1hh and 2hh ... followed by one hand-hoe weeding (28 days after planting) is the most .... Mean effects of different IWM approaches on growth and yield of maize at Ikulwe S .... Efficiency of plant population.

  6. a technique for identification of intrinsic resistance of maize varieties ...

    African Journals Online (AJOL)

    Mgina

    A new technique used to identify resistant maize varieties to the maize weevil, Sitophilus zeamais. (Motsch.) infestations is ... unreliable in terms of timely availability, high .... Influence of nutrition on performance of different insects ... that host-plant resistance as a pest control ..... age, diet, female density and host resource.

  7. Dissipation and residue of ethephon in maize ifeld

    Institute of Scientific and Technical Information of China (English)

    DONG Jian-nan; MA Yong-qiang; LIU Feng-mao; JIANG Nai-wen; JIAN Qiu

    2015-01-01

    A rapid and reliable method was developed for analysis of ethephon residues in maize, in combination with the investigation of its dissipation in ifeld condition and stabilities during the sample storage. The residue analytical method in maize plant, maize kernel and soil was developed based on the quantiifcation of ethylene produced from the derivatization of ethephon residue by adding the saturated potassium hydroxide solution to the sample. The determination was carried out by using the head space gas chromatography with lfame ionization detector (HS-GC-FID). The limit of quantiifcation (LOQ) of the method for maize plant was 0.05, 0.02 mg kg–1 for maize kernel and 0.05 mg kg–1 for soil, respectively. The fortiifed recoveries of the method were from 84.6–102.6%, with relative standard deviations of 7.9–3.8%. Using the methods, the dissipation of ephethon in maize plant or soil was investigated. The half life of ethephon degradation was from 0.6 to 3.3 d for plant and 0.7 to 5.7 d for soil, respectively. The storage stabilities of ethephon residues were determined in fresh and dry kernels with homogenization and without homogenization process. And the result showed that ethephon residues in maize kernels were stable under –18°C for 6 mon. The results were helpful to monitor the residue dissipation of ethephon in the maize ecosystem for further ecological risk assessment.

  8. A single molecule scaffold for the maize genome

    Science.gov (United States)

    About 85% of the maize genome consists of highly repetitive Sequences that are interspersed by low copy, gene-coding sequences. The maize community has dealt with this genomic complexity by the Construction of an integrated genetic and physical map (iMap), but this resource alone was not sufficient ...

  9. Intraplant communication in maize contributes to defense against insects

    Science.gov (United States)

    The vasculature of plants act as a channel for transport of signal(s) that facilitate long-distance intraplant communication. In maize, Maize insect resistance1-Cysteine Protease (Mir1-CP), which has homology to papain-like proteases, provides defense to different feeding guilds of insect pests. Fur...

  10. Interaction of maize chromatin-associated HMG proteins with mononucleosomes

    DEFF Research Database (Denmark)

    Lichota, J.; Grasser, Klaus D.

    2003-01-01

    maize HMGA and five different HMGB proteins with mononucleosomes (containing approx. 165 bp of DNA) purified from micrococcal nuclease-digested maize chromatin. The HMGB proteins interacted with the nucleosomes independent of the presence of the linker histone H1, while the binding of HMGA...

  11. Maize development: Cell wall changes in leaves and sheaths

    Science.gov (United States)

    Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades, including the midribs and sheaths, undergo cell wall changes as cells transition to fully mature cell ty...

  12. Constructing a Cytogenetic Map of the Maize Genome

    Science.gov (United States)

    We are developing a pachytene cytogenetic FISH (Fluorescence in situ Hybridization) map of the maize (Zea mays L.) genome using maize marker-selected sorghum BACs (Bacterial Artificial Chromosome) as described by Koumbaris and Bass (2003, Plant J. 35:647). The two main projects are the production of...

  13. Extraction and characterization of natural cellulose fibers from maize tassel

    CSIR Research Space (South Africa)

    Maepa, CE

    2015-04-01

    Full Text Available treatment. FT-IR spectroscopic analysis of maize tassel fibers confirmed that this chemical treatment also shows the way to partial elimination of hemicelluloses and lignin from the structure of the maize tassel fibers. X-ray diffraction results indicated...

  14. Genetic analysis of teosinte for kernel composition traits in maize

    Science.gov (United States)

    Teosinte (Zea mays ssp. parviglumis) is the wild ancestor of modern maize (Zea mays ssp. mays). Teosinte contains greater genetic diversity compared to maize inbreds and landraces, but its use is limited by insufficient genetic resources to evaluate its value. A population of teosinte near isogenic ...

  15. Influence of Seed Coating Formulations on Maize Production

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Effects of four coating formulations on maize production were studied. The results showec that all coating formulations had some effects on improving maize seedlings, strengthening the resistance againt diseases and pests and increasing the yields in dtifferent degrees, especially Paxil which increased the com yield by 12.0%, significantly higher than the control.

  16. Status and prospects of maize research in Nepal

    Directory of Open Access Journals (Sweden)

    Govind KC

    2015-12-01

    Full Text Available Food and nutritional securities are the major threats coupled with declining factor productivity and climate change effects in Nepal. Maize being the principal food crops of the majority of the hill people and source of animal feed for ever growing livestock industries in Terai of Nepal. Despite the many efforts made to increase the maize productivity in the country, the results are not much encouraging. Many of the maize based technologies developed and recommended for the farmers to date are not fully adopted. Therefore, problem is either on technology development or on dissemination or on both. Considering the above facts, some of the innovative and modern approaches of plant breeding and crop management technologies to increase the maize yield need to be developed and disseminated. There is a need for location-specific maize production technologies, especially for lowland winter maize, marginal upland maize production system, and resource poor farmers. Research efforts can be targeted to address both yield potential and on-farm yields by reducing the impacts of abiotic and biotic constraints. Therefore, in order to streamline the future direction of maize research in Nepal, an attempt has been made in this article to highlight the present status and future prospects with few key pathways.

  17. Climate change compromises the immune response of maize

    Science.gov (United States)

    Maize is by quantity the most important C4 cereal crop in the US; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2] is a driving force behind the warmer temperatures and drought, whi...

  18. Cost-benefit analysis of replacing maize with rice husk ...

    African Journals Online (AJOL)

    Cost-benefit analysis of replacing maize with rice husk supplemented with grindazyme, nutrsea ... Log in or Register to get access to full text downloads. ... Rice husk was added at the expense of maize in the control diet and each experimental ...

  19. Sporophytic control of pollen tube growth and guidance in maize.

    Science.gov (United States)

    Lausser, Andreas; Kliwer, Irina; Srilunchang, Kanok-orn; Dresselhaus, Thomas

    2010-03-01

    Pollen tube germination, growth, and guidance (progamic phase) culminating in sperm discharge is a multi-stage process including complex interactions between the male gametophyte as well as sporophytic tissues and the female gametophyte (embryo sac), respectively. Inter- and intra-specific crossing barriers in maize and Tripsacum have been studied and a precise description of progamic pollen tube development in maize is reported here. It was found that pollen germination and initial tube growth are rather unspecific, but an early, first crossing barrier was detected before arrival at the transmitting tract. Pollination of maize silks with Tripsacum pollen and incompatible pollination of Ga1s/Ga1s-maize silks with ga1-maize pollen revealed another two incompatibility barriers, namely transmitting tract mistargeting and insufficient growth support. Attraction and growth support by the transmitting tract seem to play key roles for progamic pollen tube growth. After leaving transmitting tracts, pollen tubes have to navigate across the ovule in the ovular cavity. Pollination of an embryo sac-less maize RNAi-line allowed the role of the female gametophyte for pollen tube guidance to be determined in maize. It was found that female gametophyte controlled guidance is restricted to a small region around the micropyle, approximately 50-100 microm in diameter. This area is comparable to the area of influence of previously described ZmEA1-based short-range female gametophyte signalling. In conclusion, the progamic phase is almost completely under sporophytic control in maize.

  20. 19 CFR 10.57 - Certified seed potatoes, and seed corn or maize.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Certified seed potatoes, and seed corn or maize... Provisions Potatoes, Corn, Or Maize § 10.57 Certified seed potatoes, and seed corn or maize. Claim for classification as seed potatoes under subheading 0701.10.00, as seed corn (maize) under subheading...