Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.).

Science.gov (United States)

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-02-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Characterization of Indian and exotic quality protein maize (QPM ...

African Journals Online (AJOL)

Polymorphism analysis and genetic diversity of normal maize and quality protein maize (QPM) inbreds among locally well adapted germplasm is a prerequisite for hybrid maize breeding program. The diversity analyses of 48 maize accessions including Indian and exotic germplasm using 75 simple sequence repeat (SSR) ...

Genomic-based-breeding tools for tropical maize improvement.

Science.gov (United States)

Chakradhar, Thammineni; Hindu, Vemuri; Reddy, Palakolanu Sudhakar

2017-12-01

Maize has traditionally been the main staple diet in the Southern Asia and Sub-Saharan Africa and widely grown by millions of resource poor small scale farmers. Approximately, 35.4 million hectares are sown to tropical maize, constituting around 59% of the developing worlds. Tropical maize encounters tremendous challenges besides poor agro-climatic situations with average yields recorded <3 tones/hectare that is far less than the average of developed countries. On the contrary to poor yields, the demand for maize as food, feed, and fuel is continuously increasing in these regions. Heterosis breeding introduced in early 90 s improved maize yields significantly, but genetic gains is still a mirage, particularly for crop growing under marginal environments. Application of molecular markers has accelerated the pace of maize breeding to some extent. The availability of array of sequencing and genotyping technologies offers unrivalled service to improve precision in maize-breeding programs through modern approaches such as genomic selection, genome-wide association studies, bulk segregant analysis-based sequencing approaches, etc. Superior alleles underlying complex traits can easily be identified and introgressed efficiently using these sequence-based approaches. Integration of genomic tools and techniques with advanced genetic resources such as nested association mapping and backcross nested association mapping could certainly address the genetic issues in maize improvement programs in developing countries. Huge diversity in tropical maize and its inherent capacity for doubled haploid technology offers advantage to apply the next generation genomic tools for accelerating production in marginal environments of tropical and subtropical world. Precision in phenotyping is the key for success of any molecular-breeding approach. This article reviews genomic technologies and their application to improve agronomic traits in tropical maize breeding has been reviewed in

Zea mI, the maize homolog of the allergen-encoding Lol pI gene of rye grass.

Science.gov (United States)

Broadwater, A H; Rubinstein, A L; Chay, C H; Klapper, D G; Bedinger, P A

1993-09-15

Sequence analysis of a pollen-specific cDNA from maize has identified a homolog (Zea mI) of the gene (Lol pI) encoding the major allergen of rye-grass pollen. The protein encoded by the partial cDNA sequence is 59.3% identical and 72.7% similar to the comparable region of the reported amino acid sequence of Lol pIA. Southern analysis indicates that this cDNA represents a member of a small multigene family in maize. Northern analysis shows expression only in pollen, not in vegetative or female floral tissues. The timing of expression is developmentally regulated, occurring at a low level prior to the first pollen mitosis and at a high level after this postmeiotic division. Western analysis detects a protein in maize pollen lysates using polyclonal antiserum and monoclonal antibodies directed against purified Lolium perenne allergen.

Sequencing, assembly, and annotation of Maize B104 : A maize transformation resource

Science.gov (United States)

Maize transformation is complicated. Most lines are not readily cultured and transformed, making the germplasm available for genome engineering extremely limited. Developing a better understanding of the genomic regions responsible for differences in culturability and transformability would be a goo...

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identify novel genes expressed during vegetative, infectious, and reproductive growth.

Science.gov (United States)

Bluhm, Burton H; Dhillon, Braham; Lindquist, Erika A; Kema, Gert Hj; Goodwin, Stephen B; Dunkle, Larry D

2008-11-04

The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs) from C. zeae-maydis and evaluate their expression during vegetative, infectious, and reproductive growth. A total of 27,551 ESTs was obtained from five cDNA libraries constructed from vegetative and sporulating cultures of C. zeae-maydis. The ESTs, grouped into 4088 clusters and 531 singlets, represented 4619 putative unique genes. Of these, 36% encoded proteins similar (E value zeae-maydis, providing specific targets for characterization by molecular genetics and functional genomics. The EST data establish a foundation for future studies in evolutionary and comparative genomics among species of Cercospora and other groups of plant pathogenic fungi.

The W22 genome: a foundation for maize functional genomics and transposon biology

Science.gov (United States)

The maize W22 inbred has served as a platform for maize genetics since the mid twentieth century. To streamline maize genome analyses, we have sequenced and de novo assembled a W22 reference genome using small-read sequencing technologies. We show that significant structural heterogeneity exists in ...

PHYSICAL ATTRIBUTES OF SOIL AFTER SWINE WASTEWATER APPLICATION AS COVER FERTILIZER ON MAIZE CROP AND BLACK OATS SEQUENCE

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FÁBIO PALCZEWSKI PACHECO

2017-01-01

Full Text Available The rate of swine wastewater application (SW in agricultural production could result in the replacement of chemical fertilizers. However, SW destroys soil physical properties by decreasing pore bulk, which negatively affects both crop yield and development. In this context, this study aimed at monitoring the influence of swine wastewater as a cover fertilizer in maize and black oats in sequence on soil physical properties. Five application rates (0, 100, 200, 300 and 537 m3ha - 1 equivalent to 0, 11.2, 22.3, 33.5 and 60 kg ha-1 N, respectively, based on the average nitrogen concentration in SW were tested with four replications each. In the studied area, soil porosity, density, and water content, before maize sowing and at the end of the cycles of maize and black oats, were determined by the volumetric ring method. Data were submitted for regression analyses. There was a reduction in the macroporosity and total porosity of the soil when the SW application rate, before maize cultivation, was higher. The introduction of black oats helped to improve the physical quality of the soil and reduced the compaction of the surface layer from 0 to 15 cm and 100 to 300 m3 ha-1 SW rates.

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identity novel genes expressed during vegetative infectious, and repoductive growth

OpenAIRE

Bluhm, B.H.; Lindquist, E.; Kema, G.H.J.; Goodwin, S.B.; Dunkle, L.D.

2008-01-01

The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs) from C. zeae-maydis and evaluate their expression during vegetative, infectious, and reproductive growth. R...

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identify novel genes expressed during vegetative, infectious, and reproductive growth

OpenAIRE

Bluhm, Burton H; Dhillon, Braham; Lindquist, Erika A; Kema, Gert HJ; Goodwin, Stephen B; Dunkle, Larry D

2008-01-01

Abstract Background The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs) from C. zeae-maydis and evaluate their expression during vegetative, infectious, and re...

Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History.

Science.gov (United States)

Correa-Galeote, David; Bedmar, Eulogio J; Arone, Gregorio J

2018-01-01

The bacterial endophytic communities residing within roots of maize ( Zea mays L.) plants cultivated by a sustainable management in soils from the Quechua maize belt (Peruvian Andes) were examined using tags pyrosequencing spanning the V4 and V5 hypervariable regions of the 16S rRNA. Across four replicate libraries, two corresponding to sequences of endophytic bacteria from long time maize-cultivated soils and the other two obtained from fallow soils, 793 bacterial sequences were found that grouped into 188 bacterial operational taxonomic units (OTUs, 97% genetic similarity). The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from fallow soils. A mean of 30 genera were found in the fallow soil libraries and 47 were in those from the maize-cultivated soils. Both alpha and beta diversity indexes showed clear differences between bacterial endophytic populations from plants with different soil cultivation history and that the soils cultivated for long time requires a higher diversity of endophytes. The number of sequences corresponding to main genera Sphingomonas, Herbaspirillum, Bradyrhizobium and Methylophilus in the maize-cultivated libraries were statistically more abundant than those from the fallow soils. Sequences of genera Dyella and Sreptococcus were significantly more abundant in the libraries from the fallow soils. Relative abundance of genera Burkholderia, candidatus Glomeribacter, Staphylococcus, Variovorax, Bacillus and Chitinophaga were similar among libraries. A canonical correspondence analysis of the relative abundance of the main genera showed that the four libraries distributed in two clearly separated groups. Our results suggest that cultivation history is an important driver of endophytic colonization of maize and that after a long time of cultivation of the soil the maize plants need to increase the richness of the bacterial endophytes communities.

Site Specific Nutrient Management for Maize on Ultisols Lampung

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Andarias Makka Murni

2010-01-01

Full Text Available Lampung is the third major maize producing province in Indonesia after East Java and Central Java. In Lampungmaize is cultivated mainly in upland areas with ultisols and only some cultivated on paddy field as a secondary cropin the dry season. The average maize yield in Lampung is still 3.4 Mg ha-1 bellow yield potential of 7 - 10 Mg ha-1. Toincrease the productivity of maize through site-specific nutrient management (SSNM, on-farm trials were conductedin five locations in Lampung i.e. four locations in Central Lampung District (Sidowaras, Binjai Ngagung, Watu Agungand Balai Rejo and one location in South Lampung District (Trimulyo, Tegineneng Sub District during the 2004/2005,2005/2006 and 2006/2007 rainy seasons. The experimental setup followed a standard protocol at all sites and includednutrient omission plots (PK, NK, NP to estimate indigenous nutrient supplies, an NPK plot to measure yield responseto fertilizer application, and a farmers’ fertilizer practice (FFP plot in each farmer’s field. An SSNM treatment plot wasincluded in the second and third seasons. Each of the above treatments was paralleled by a plot with improved cropmanagement practice (ICM, i.e. higher planting density, addition of lime, and addition of magnesium. Results showedthat yield response to fertilizer N, P and K application in these sites were: N = 2.3 - 4.1 Mg ha-1; P = 0.6 - 2.0 Mg ha-1;K = 0.3-2.4 Mg ha-1. Attainable yield in the three seasons on average ranged from 7.6 Mg ha-1 to 10.6 Mg ha-1. Yield inthe SSNM treatment (with or without ICM was significantly higher than the FFP indicating great opportunities forfarmers to increase productivity and profitability with improved nutrient and crop management

Partial characterization of Maize rayado fino virus isolates from Ecuador: phylogenetic analysis supports a Central American origin of the virus.

Science.gov (United States)

Chicas, Mauricio; Caviedes, Mario; Hammond, Rosemarie; Madriz, Kenneth; Albertazzi, Federico; Villalobos, Heydi; Ramírez, Pilar

2007-06-01

Maize rayado fino virus (MRFV) infects maize and appears to be restricted to, yet widespread in, the Americas. MRFV was previously unreported from Ecuador. Maize plants exhibiting symptoms of MRFV infection were collected at the Santa Catalina experiment station in Quito, Ecuador. RT-PCR reactions were performed on total RNA extracted from the symptomatic leaves using primers specific for the capsid protein (CP) gene and 3' non-translated region of MRFV and first strand cDNA as a template. Nucleotide sequence comparisons to previously sequenced MRFV isolates from other geographic regions revealed 88-91% sequence identity. Phylogenetic trees constructed using Maximum Likelihood, UPGMA, Minimal Evolution, Neighbor Joining, and Maximum Parsimony methods separated the MRFV isolates into four groups. These groups may represent geographic isolation generated by the mountainous chains of the American continent. Analysis of the sequences and the genetic distances among the different isolates suggests that MRFV may have originated in Mexico and/or Guatemala and from there it dispersed to the rest of the Americas.

Computational prediction and molecular confirmation of Helitron transposons in the maize genome

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He Limei

2008-01-01

Full Text Available Abstract Background Helitrons represent a new class of transposable elements recently uncovered in plants and animals. One remarkable feature of Helitrons is their ability to capture gene sequences, which makes them of considerable potential evolutionary importance. However, because Helitrons lack the typical structural features of other DNA transposable elements, identifying them is a challenge. Currently, most researchers identify Helitrons manually by comparing sequences. With the maize whole genome sequencing project underway, an automated computational Helitron searching tool is needed. The characterization of Helitron activities in maize needs to be addressed in order to better understand the impact of Helitrons on the organization of the genome. Results We developed and implemented a heuristic searching algorithm in PERL for identifying Helitrons. Our HelitronFinder program will (i take FASTA-formatted DNA sequences as input and identify the hairpin looping patterns, and (ii exploit the consensus 5' and 3' end sequences of known Helitrons to identify putative ends. We randomly selected five predicted Helitrons from the program's high quality output for molecular verification. Four out of the five predicted Helitrons were confirmed by PCR assays and DNA sequencing in different maize inbred lines. The HelitronFinder program identified two head-to-head dissimilar Helitrons in a maize BAC sequence. Conclusion We have identified 140 new Helitron candidates in maize with our computational tool HelitronFinder by searching maize DNA sequences currently available in GenBank. Four out of five candidates were confirmed to be real by empirical methods, thus validating the predictions of HelitronFinder. Additional points to emerge from our study are that Helitrons do not always insert at an AT dinucleotide in the host sequences, that they can insert immediately adjacent to an existing Helitron, and that their movement may cause changes in the flanking

Biotechnology in maize breeding

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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.

The physical and genetic framework of the maize B73 genome.

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Fusheng Wei

2009-11-01

Full Text Available Maize is a major cereal crop and an important model system for basic biological research. Knowledge gained from maize research can also be used to genetically improve its grass relatives such as sorghum, wheat, and rice. The primary objective of the Maize Genome Sequencing Consortium (MGSC was to generate a reference genome sequence that was integrated with both the physical and genetic maps. Using a previously published integrated genetic and physical map, combined with in-coming maize genomic sequence, new sequence-based genetic markers, and an optical map, we dynamically picked a minimum tiling path (MTP of 16,910 bacterial artificial chromosome (BAC and fosmid clones that were used by the MGSC to sequence the maize genome. The final MTP resulted in a significantly improved physical map that reduced the number of contigs from 721 to 435, incorporated a total of 8,315 mapped markers, and ordered and oriented the majority of FPC contigs. The new integrated physical and genetic map covered 2,120 Mb (93% of the 2,300-Mb genome, of which 405 contigs were anchored to the genetic map, totaling 2,103.4 Mb (99.2% of the 2,120 Mb physical map. More importantly, 336 contigs, comprising 94.0% of the physical map ( approximately 1,993 Mb, were ordered and oriented. Finally we used all available physical, sequence, genetic, and optical data to generate a golden path (AGP of chromosome-based pseudomolecules, herein referred to as the B73 Reference Genome Sequence version 1 (B73 RefGen_v1.

Breeding of speciality maize for industrial purposes

OpenAIRE

Pajić Zorica; Radosavljević Milica; Filipović Milomir; Todorović Goran; Srdić Jelena; Pavlov Milovan

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...

Expression of a maize Myb transcription factor driven by a putative silk-specific promoter significantly enhances resistance to Helicoverpa zea in transgenic maize.

Science.gov (United States)

Johnson, Eric T; Berhow, Mark A; Dowd, Patrick F

2007-04-18

Hi II maize (Zea mays) plants were engineered to express maize p1 cDNA, a Myb transcription factor, controlled by a putative silk specific promoter, for secondary metabolite production and corn earworm resistance. Transgene expression did not enhance silk color, but about half of the transformed plant silks displayed browning when cut, which indicated the presence of p1-produced secondary metabolites. Levels of maysin, a secondary metabolite with insect toxicity, were highest in newly emerged browning silks. The insect resistance of transgenic silks was also highest at emergence, regardless of maysin levels, which suggests that other unidentified p1-induced molecules likely contributed to larval mortality. Mean survivor weights of corn earworm larvae fed mature browning transgenic silks were significantly lower than weights of those fed mature nonbrowning transgenic silks. Some transgenic pericarps browned with drying and contained similar molecules found in pericarps expressing a dominant p1 allele, suggesting that the promoter may not be silk-specific.

Maize cob losses and their effects on the poverty status of maize

African Journals Online (AJOL)

This study analysed fresh maize cob losses and its effect on the poverty status of maize farmers in Edo State,. Nigeria. The specific .... is the poverty gap for ... Total cost. 162,367.48. 100.00. Returns. Total expected yield (N). 327,966.63. _.

ProFITS of maize: a database of protein families involved in the transduction of signalling in the maize genome

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Zhang Zhenhai

2010-10-01

Full Text Available Abstract Background Maize (Zea mays ssp. mays L. is an important model for plant basic and applied research. In 2009, the B73 maize genome sequencing made a great step forward, using clone by clone strategy; however, functional annotation and gene classification of the maize genome are still limited. Thus, a well-annotated datasets and informative database will be important for further research discoveries. Signal transduction is a fundamental biological process in living cells, and many protein families participate in this process in sensing, amplifying and responding to various extracellular or internal stimuli. Therefore, it is a good starting point to integrate information on the maize functional genes involved in signal transduction. Results Here we introduce a comprehensive database 'ProFITS' (Protein Families Involved in the Transduction of Signalling, which endeavours to identify and classify protein kinases/phosphatases, transcription factors and ubiquitin-proteasome-system related genes in the B73 maize genome. Users can explore gene models, corresponding transcripts and FLcDNAs using the three abovementioned protein hierarchical categories, and visualize them using an AJAX-based genome browser (JBrowse or Generic Genome Browser (GBrowse. Functional annotations such as GO annotation, protein signatures, protein best-hits in the Arabidopsis and rice genome are provided. In addition, pre-calculated transcription factor binding sites of each gene are generated and mutant information is incorporated into ProFITS. In short, ProFITS provides a user-friendly web interface for studies in signal transduction process in maize. Conclusion ProFITS, which utilizes both the B73 maize genome and full length cDNA (FLcDNA datasets, provides users a comprehensive platform of maize annotation with specific focus on the categorization of families involved in the signal transduction process. ProFITS is designed as a user-friendly web interface and it is

Promzea: a pipeline for discovery of co-regulatory motifs in maize and other plant species and its application to the anthocyanin and phlobaphene biosynthetic pathways and the Maize Development Atlas.

Science.gov (United States)

Liseron-Monfils, Christophe; Lewis, Tim; Ashlock, Daniel; McNicholas, Paul D; Fauteux, François; Strömvik, Martina; Raizada, Manish N

2013-03-15

The discovery of genetic networks and cis-acting DNA motifs underlying their regulation is a major objective of transcriptome studies. The recent release of the maize genome (Zea mays L.) has facilitated in silico searches for regulatory motifs. Several algorithms exist to predict cis-acting elements, but none have been adapted for maize. A benchmark data set was used to evaluate the accuracy of three motif discovery programs: BioProspector, Weeder and MEME. Analysis showed that each motif discovery tool had limited accuracy and appeared to retrieve a distinct set of motifs. Therefore, using the benchmark, statistical filters were optimized to reduce the false discovery ratio, and then remaining motifs from all programs were combined to improve motif prediction. These principles were integrated into a user-friendly pipeline for motif discovery in maize called Promzea, available at http://www.promzea.org and on the Discovery Environment of the iPlant Collaborative website. Promzea was subsequently expanded to include rice and Arabidopsis. Within Promzea, a user enters cDNA sequences or gene IDs; corresponding upstream sequences are retrieved from the maize genome. Predicted motifs are filtered, combined and ranked. Promzea searches the chosen plant genome for genes containing each candidate motif, providing the user with the gene list and corresponding gene annotations. Promzea was validated in silico using a benchmark data set: the Promzea pipeline showed a 22% increase in nucleotide sensitivity compared to the best standalone program tool, Weeder, with equivalent nucleotide specificity. Promzea was also validated by its ability to retrieve the experimentally defined binding sites of transcription factors that regulate the maize anthocyanin and phlobaphene biosynthetic pathways. Promzea predicted additional promoter motifs, and genome-wide motif searches by Promzea identified 127 non-anthocyanin/phlobaphene genes that each contained all five predicted promoter

Maize variety and method of production

Science.gov (United States)

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.

Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize.

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María Florencia Realini

Full Text Available In Argentina there are two different centers of maize diversity, the Northeastern (NEA and the Northwestern (NWA regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1 did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10 chromosomes were found with low frequency (0.1≥f ≤0.40 in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity.

Genetic diversity of Pakistani maize genotypes using chromosome ...

African Journals Online (AJOL)

For improvement of maize crop presence of genetic diversity in the germplasm is very important. This study was conducted to determine genetic diversity among 17 Pakistani maize genotypes using 10 simple sequence repeat (SSR) primer sets. All the amplification products were in the range of <250-750 bp. To estimate the ...

Transcriptome analysis of cadmium-treated roots in maize (Zea mays L.

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Runqing Yue

2016-08-01

Full Text Available Cadmium (Cd is a heavy metal and is highly toxic to all plant species. However, the underlying molecular mechanism controlling the effects of auxin on the Cd stress response in maize is largely unknown. In this study, the transcriptome produced by maize ‘Zheng 58’ root responses to Cd stress was sequenced using Illumina sequencing technology. In our study, six RNA-seq libraries yielded a total of 244 million clean short reads and 30.37 Gb of sequence data. A total of 6342 differentially expressed genes (DEGs were grouped into 908 Gene Ontology (GO categories and 198 Kyoto Encyclopedia of Genes and Genomes terms. GO term enrichment analysis indicated that various auxin signaling pathway-related GO terms were significantly enriched in DEGs. Comparison of the transcript abundances for auxin biosynthesis, transport, and downstream response genes revealed a universal expression response under Cd treatment. Furthermore, our data showed that free indole-3-acetic acid (IAA levels were significantly reduced; but IAA oxidase activity was up-regulated after Cd treatment in maize roots. The analysis of Cd activity in maize roots under different Cd and auxin conditions confirmed that auxin affected Cd accumulation in maize seedlings. These results will improve our understanding of the complex molecular mechanisms underlying the response to Cd stress in maize roots.

Bacterial communities in the rhizosphere of amilaceous maize (Zea mays L. as assessed by pyrosequencing

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David Correa-Galeote

2016-07-01

Full Text Available Maize (Zea mays L. is the staple diet of the native peasants in the Quechua region of the Peruvian Andes who continue growing it in small plots called chacras following ancestral traditions. The abundance and structure of bacterial communities associated with the roots of amilaceous maize has not been studied in Andean chacras. Accordingly, the main objective of this study was to describe the rhizospheric bacterial diversity of amilaceous maize grown either in the presence or the absence of bur clover cultivated in soils from the Quechua maize belt. Three 16S rRNA gene libraries, one corresponding to sequences of bacteria from bulk soil of a chacra maintained under fallow conditions, the second from the rhizosphere of maize-cultivated soils, and the third prepared from rhizospheric soil of maize cultivated in intercropping with bur clover were examined using pyrosequencing tags spanning the V4 and V5 hypervariable regions of the gene. A total of 26031 sequences were found that grouped into 5955 distinct operational taxonomic units which distributed in 309 genera. The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from bulk soil. One hundred ninety seven genera were found in the bulk soil library and 234 and 203 were in those from the maize and maize/bur clover-cultivated soils. Sixteen out of the 309 genera had a relative abundance higher than 0.5% and the were (in decreasing order of abundance Gp4, Gp6, Flavobacterium, Subdivision3 genera incertae sedis of the Verrucomicrobia phylum, Gemmatimonas, Dechloromonas, Ohtaekwangia, Rhodoferax, Gaiella, Opitutus, Gp7, Spartobacteria genera incertae sedis, Terrimonas, Gp5, Steroidobacter and Parcubacteria genera incertae sedis. Genera Gp4 and Gp6 of the Acidobacteria, Gemmatimonas and Rhodoferax were the most abundant in bulk soil, whereas Flavobacterium, Dechloromonas and Ohtaekwangia were the main genera in the rhizosphere

Genome sequence of a 5,310-year-old maize cob provides insights into the early stages of maize domestication

DEFF Research Database (Denmark)

Ramos Madrigal, Jazmin; Smith, Bruce D.; Moreno Mayar, José Victor

2016-01-01

The complex evolutionary history of maize (Zea mays L. ssp. mays) has been clarified with genomic-level data from modern landraces and wild teosinte grasses [1, 2], augmenting archaeological findings that suggest domestication occurred between 10,000 and 6,250 years ago in southern Mexico [3, 4......]. Maize rapidly evolved under human selection, leading to conspicuous phenotypic transformations, as well as adaptations to varied environments [5]. Still, many questions about the domestication process remain unanswered because modern specimens do not represent the full range of past diversity due...... to abandonment of unproductive lineages, genetic drift, on-going natural selection, and recent breeding activity. To more fully understand the history and spread of maize, we characterized the draft genome of a 5,310-year-old archaeological cob excavated in the Tehuacan Valley of Mexico. We compare this ancient...

Automated Leaf Tracking using Multi-view Image Sequences of Maize Plants for Leaf-growth Monitoring

Science.gov (United States)

Das Choudhury, S.; Awada, T.; Samal, A.; Stoerger, V.; Bashyam, S.

2017-12-01

Extraction of phenotypes with botanical importance by analyzing plant image sequences has the desirable advantages of non-destructive temporal phenotypic measurements of a large number of plants with little or no manual intervention in a relatively short period of time. The health of a plant is best interpreted by the emergence timing and temporal growth of individual leaves. For automated leaf growth monitoring, it is essential to track each leaf throughout the life cycle of the plant. Plants are constantly changing organisms with increasing complexity in architecture due to variations in self-occlusions and phyllotaxy, i.e., arrangements of leaves around the stem. The leaf cross-overs pose challenges to accurately track each leaf using single view image sequence. Thus, we introduce a novel automated leaf tracking algorithm using a graph theoretic approach by multi-view image sequence analysis based on the determination of leaf-tips and leaf-junctions in the 3D space. The basis of the leaf tracking algorithm is: the leaves emerge using bottom-up approach in the case of a maize plant, and the direction of leaf emergence strictly alternates in terms of direction. The algorithm involves labeling of the individual parts of a plant, i.e., leaves and stem, following graphical representation of the plant skeleton, i.e., one-pixel wide connected line obtained from the binary image. The length of the leaf is measured by the number of pixels in the leaf skeleton. To evaluate the performance of the algorithm, a benchmark dataset is indispensable. Thus, we publicly release University of Nebraska-Lincoln Component Plant Phenotyping dataset-2 (UNL-CPPD-2) consisting of images of the 20 maize plants captured by visible light camera of the Lemnatec Scanalyzer 3D high throughout plant phenotyping facility once daily for 60 days from 10 different views. The dataset is aimed to facilitate the development and evaluation of leaf tracking algorithms and their uniform comparisons.

Characterization of a Novel Polerovirus Infecting Maize in China.

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Chen, Sha; Jiang, Guangzhuang; Wu, Jianxiang; Liu, Yong; Qian, Yajuan; Zhou, Xueping

2016-04-28

A novel virus, tentatively named Maize Yellow Mosaic Virus (MaYMV), was identified from the field-grown maize plants showing yellow mosaic symptoms on the leaves collected from the Yunnan Province of China by the deep sequencing of small RNAs. The complete 5642 nucleotide (nt)-long genome of the MaYMV shared the highest nucleotide sequence identity (73%) to Maize Yellow Dwarf Virus-RMV. Sequence comparisons and phylogenetic analyses suggested that MaYMV represents a new member of the genus Polerovirus in the family Luteoviridae. Furthermore, the P0 protein encoded by MaYMV was demonstrated to inhibit both local and systemic RNA silencing by co-infiltration assays using transgenic Nicotiana benthamiana line 16c carrying the GFP reporter gene, which further supported the identification of a new polerovirus. The biologically-active cDNA clone of MaYMV was generated by inserting the full-length cDNA of MaYMV into the binary vector pCB301. RT-PCR and Northern blot analyses showed that this clone was systemically infectious upon agro-inoculation into N. benthamiana. Subsequently, 13 different isolates of MaYMV from field-grown maize plants in different geographical locations of Yunnan and Guizhou provinces of China were sequenced. Analyses of their molecular variation indicate that the 3' half of P3-P5 read-through protein coding region was the most variable, whereas the coat protein- (CP-) and movement protein- (MP-)coding regions were the most conserved.

Characterization of a Novel Polerovirus Infecting Maize in China

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Sha Chen

2016-04-01

Full Text Available A novel virus, tentatively named Maize Yellow Mosaic Virus (MaYMV, was identified from the field-grown maize plants showing yellow mosaic symptoms on the leaves collected from the Yunnan Province of China by the deep sequencing of small RNAs. The complete 5642 nucleotide (nt-long genome of the MaYMV shared the highest nucleotide sequence identity (73% to Maize Yellow Dwarf Virus-RMV. Sequence comparisons and phylogenetic analyses suggested that MaYMV represents a new member of the genus Polerovirus in the family Luteoviridae. Furthermore, the P0 protein encoded by MaYMV was demonstrated to inhibit both local and systemic RNA silencing by co-infiltration assays using transgenic Nicotiana benthamiana line 16c carrying the GFP reporter gene, which further supported the identification of a new polerovirus. The biologically-active cDNA clone of MaYMV was generated by inserting the full-length cDNA of MaYMV into the binary vector pCB301. RT-PCR and Northern blot analyses showed that this clone was systemically infectious upon agro-inoculation into N. benthamiana. Subsequently, 13 different isolates of MaYMV from field-grown maize plants in different geographical locations of Yunnan and Guizhou provinces of China were sequenced. Analyses of their molecular variation indicate that the 3′ half of P3–P5 read-through protein coding region was the most variable, whereas the coat protein- (CP- and movement protein- (MP-coding regions were the most conserved.

Loop-mediated isothermal amplification (LAMP) method for detection of genetically modified maize T25.

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Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan

2013-11-01

The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg(-1) GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25.

Specific gene mutations induced by heavy ions

International Nuclear Information System (INIS)

Freeling, M.; Karoly, C.W.; Cheng, D.S.K.

1980-01-01

This report summarizes our heavy-ion research rationale, progress, and plans for the near future. The major project involves selecting a group of maize Adh1 mutants induced by heavy ions and correlating their altered behavior with altered DNA nucleotide sequences and sequence arrangements. This research requires merging the techniques of classical genetics and recombinant DNA technology. Our secondary projects involve (1) the use of the Adh gene in the fruit fly, Drosophila melanogaster, as a second system with which to quantify the sort of specific gene mutants induced by heavy ions as compared to x rays, and (2) the development of a maize Adh1 pollen in situ monitor for environmental mutagens

Enhanced virus resistance in transgenic maize expressing a dsRNA-specific endoribonuclease gene from E. coli.

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Xiuling Cao

Full Text Available Maize rough dwarf disease (MRDD, caused by several Fijiviruses in the family Reoviridae, is a global disease that is responsible for substantial yield losses in maize. Although some maize germplasm have low levels of polygenic resistance to MRDD, highly resistant cultivated varieties are not available for agronomic field production in China. In this work, we have generated transgenic maize lines that constitutively express rnc70, a mutant E. coli dsRNA-specific endoribonuclease gene. Transgenic lines were propagated and screened under field conditions for 12 generations. During three years of evaluations, two transgenic lines and their progeny were challenged with Rice black-streaked dwarf virus (RBSDV, the causal agent of MRDD in China, and these plants exhibited reduced levels of disease severity. In two normal years of MRDD abundance, both lines were more resistant than non-transgenic plants. Even in the most serious MRDD year, six out of seven progeny from one line were resistant, whereas non-transgenic plants were highly susceptible. Molecular approaches in the T12 generation revealed that the rnc70 transgene was integrated and expressed stably in transgenic lines. Under artificial conditions permitting heavy virus inoculation, the T12 progeny of two highly resistant lines had a reduced incidence of MRDD and accumulation of RBSDV in infected plants. In addition, we confirmed that the RNC70 protein could bind directly to RBSDV dsRNA in vitro. Overall, our data show that RNC70-mediated resistance in transgenic maize can provide efficient protection against dsRNA virus infection.

Variation in DNA Methylation Patterns is More Common among Maize Inbreds than among Tissues

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Steven R. Eichten

2013-07-01

Full Text Available Chromatin modifications, such as DNA methylation, can provide heritable, epigenetic regulation of gene expression in the absence of genetic changes. A role for DNA methylation in meiotically stable marking of repetitive elements and other sequences has been demonstrated in plants. Methylation of DNA is also proposed to play a role in development through providing a mitotic memory of gene expression states established during cellular differentiation. We sought to clarify the relative levels of DNA methylation variation among different genotypes and tissues in maize ( L.. We have assessed genomewide DNA methylation patterns in leaf, immature tassel, embryo, and endosperm tissues of two inbred maize lines: B73 and Mo17. There are hundreds of regions of differential methylation present between the two genotypes. In general, the same regions exhibit differential methylation between B73 and Mo17 in each of the tissues that were surveyed. In contrast, there are few examples of tissue-specific DNA methylation variation. Only a subset of regions with tissue-specific variation in DNA methylation show similar patterns in both genotypes of maize and even fewer are associated with altered gene expression levels among the tissues. Our data indicates a limited impact of DNA methylation on developmental gene regulation within maize.

High Density Linkage Map Construction and Mapping of Yield Trait QTLs in Maize (Zea mays) Using the Genotyping-by-Sequencing (GBS) Technology

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Su, Chengfu; Wang, Wei; Gong, Shunliang; Zuo, Jinghui; Li, Shujiang; Xu, Shizhong

2017-01-01

Increasing grain yield is the ultimate goal for maize breeding. High resolution quantitative trait loci (QTL) mapping can help us understand the molecular basis of phenotypic variation of yield and thus facilitate marker assisted breeding. The aim of this study is to use genotyping-by-sequencing (GBS) for large-scale SNP discovery and simultaneous genotyping of all F2 individuals from a cross between two varieties of maize that are in clear contrast in yield and related traits. A set of 199 F2 progeny derived from the cross of varieties SG-5 and SG-7 were generated and genotyped by GBS. A total of 1,046,524,604 reads with an average of 5,258,918 reads per F2 individual were generated. This number of reads represents an approximately 0.36-fold coverage of the maize reference genome Zea_mays.AGPv3.29 for each F2 individual. A total of 68,882 raw SNPs were discovered in the F2 population, which, after stringent filtering, led to a total of 29,927 high quality SNPs. Comparative analysis using these physically mapped marker loci revealed a higher degree of synteny with the reference genome. The SNP genotype data were utilized to construct an intra-specific genetic linkage map of maize consisting of 3,305 bins on 10 linkage groups spanning 2,236.66 cM at an average distance of 0.68 cM between consecutive markers. From this map, we identified 28 QTLs associated with yield traits (100-kernel weight, ear length, ear diameter, cob diameter, kernel row number, corn grains per row, ear weight, and grain weight per plant) using the composite interval mapping (CIM) method and 29 QTLs using the least absolute shrinkage selection operator (LASSO) method. QTLs identified by the CIM method account for 6.4% to 19.7% of the phenotypic variation. Small intervals of three QTLs (qCGR-1, qKW-2, and qGWP-4) contain several genes, including one gene (GRMZM2G139872) encoding the F-box protein, three genes (GRMZM2G180811, GRMZM5G828139, and GRMZM5G873194) encoding the WD40-repeat protein, and

Deep sequencing of RNA from ancient maize kernels

DEFF Research Database (Denmark)

Fordyce, Sarah Louise; Avila Arcos, Maria del Carmen; Rasmussen, Morten

2013-01-01

The characterization of biomolecules from ancient samples can shed otherwise unobtainable insights into the past. Despite the fundamental role of transcriptomal change in evolution, the potential of ancient RNA remains unexploited - perhaps due to dogma associated with the fragility of RNA. We hy...... maize kernels. The results suggest that ancient seed transcriptomics may offer a powerful new tool with which to study plant domestication....

High-Throughput Sequencing of Small RNA Transcriptomes in Maize Kernel Identifies miRNAs Involved in Embryo and Endosperm Development.

Science.gov (United States)

Xing, Lijuan; Zhu, Ming; Zhang, Min; Li, Wenzong; Jiang, Haiyang; Zou, Junjie; Wang, Lei; Xu, Miaoyun

2017-12-14

Maize kernel development is a complex biological process that involves the temporal and spatial expression of many genes and fine gene regulation at a transcriptional and post-transcriptional level, and microRNAs (miRNAs) play vital roles during this process. To gain insight into miRNA-mediated regulation of maize kernel development, a deep-sequencing technique was used to investigate the dynamic expression of miRNAs in the embryo and endosperm at three developmental stages in B73. By miRNA transcriptomic analysis, we characterized 132 known miRNAs and six novel miRNAs in developing maize kernel, among which, 15 and 14 miRNAs were commonly differentially expressed between the embryo and endosperm at 9 days after pollination (DAP), 15 DAP and 20 DAP respectively. Conserved miRNA families such as miR159, miR160, miR166, miR390, miR319, miR528 and miR529 were highly expressed in developing embryos; miR164, miR171, miR393 and miR2118 were highly expressed in developing endosperm. Genes targeted by those highly expressed miRNAs were found to be largely related to a regulation category, including the transcription, macromolecule biosynthetic and metabolic process in the embryo as well as the vitamin biosynthetic and metabolic process in the endosperm. Quantitative reverse transcription-PCR (qRT-PCR) analysis showed that these miRNAs displayed a negative correlation with the levels of their corresponding target genes. Importantly, our findings revealed that members of the miR169 family were highly and dynamically expressed in the developing kernel, which will help to exploit new players functioning in maize kernel development.

Contributions of Zea mays subspecies mexicana haplotypes to modern maize.

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Yang, Ning; Xu, Xi-Wen; Wang, Rui-Ru; Peng, Wen-Lei; Cai, Lichun; Song, Jia-Ming; Li, Wenqiang; Luo, Xin; Niu, Luyao; Wang, Yuebin; Jin, Min; Chen, Lu; Luo, Jingyun; Deng, Min; Wang, Long; Pan, Qingchun; Liu, Feng; Jackson, David; Yang, Xiaohong; Chen, Ling-Ling; Yan, Jianbing

2017-11-30

Maize was domesticated from lowland teosinte (Zea mays ssp. parviglumis), but the contribution of highland teosinte (Zea mays ssp. mexicana, hereafter mexicana) to modern maize is not clear. Here, two genomes for Mo17 (a modern maize inbred) and mexicana are assembled using a meta-assembly strategy after sequencing of 10 lines derived from a maize-teosinte cross. Comparative analyses reveal a high level of diversity between Mo17, B73, and mexicana, including three Mb-size structural rearrangements. The maize spontaneous mutation rate is estimated to be 2.17 × 10 -8 ~3.87 × 10 -8 per site per generation with a nonrandom distribution across the genome. A higher deleterious mutation rate is observed in the pericentromeric regions, and might be caused by differences in recombination frequency. Over 10% of the maize genome shows evidence of introgression from the mexicana genome, suggesting that mexicana contributed to maize adaptation and improvement. Our data offer a rich resource for constructing the pan-genome of Zea mays and genetic improvement of modern maize varieties.

Woody legume fallow productivity, biological N2-fixation and residual benefits to two successive maize crops in Zimbabwe

NARCIS (Netherlands)

Chikowo, R.; Mapfumo, P.; Nyamugafata, P.; Giller, K.E.

2004-01-01

Three woody legumes were planted as two-year 'improved fallows' to evaluate their residual nitrogen (N) effects on two subsequent maize crops under minimum and conventional tillage management. Maize monoculture and cowpea-maize-maize sequence treatments were included as controls. N-2-fixation was

Transcriptome Dynamics during Maize Endosperm Development.

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Jianzhou Qu

Full Text Available The endosperm is a major organ of the seed that plays vital roles in determining seed weight and quality. However, genome-wide transcriptome patterns throughout maize endosperm development have not been comprehensively investigated to date. Accordingly, we performed a high-throughput RNA sequencing (RNA-seq analysis of the maize endosperm transcriptome at 5, 10, 15 and 20 days after pollination (DAP. We found that more than 11,000 protein-coding genes underwent alternative splicing (AS events during the four developmental stages studied. These genes were mainly involved in intracellular protein transport, signal transmission, cellular carbohydrate metabolism, cellular lipid metabolism, lipid biosynthesis, protein modification, histone modification, cellular amino acid metabolism, and DNA repair. Additionally, 7,633 genes, including 473 transcription factors (TFs, were differentially expressed among the four developmental stages. The differentially expressed TFs were from 50 families, including the bZIP, WRKY, GeBP and ARF families. Further analysis of the stage-specific TFs showed that binding, nucleus and ligand-dependent nuclear receptor activities might be important at 5 DAP, that immune responses, signalling, binding and lumen development are involved at 10 DAP, that protein metabolic processes and the cytoplasm might be important at 15 DAP, and that the responses to various stimuli are different at 20 DAP compared with the other developmental stages. This RNA-seq analysis provides novel, comprehensive insights into the transcriptome dynamics during early endosperm development in maize.

A genome-wide characterization of microRNA genes in maize.

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Lifang Zhang

2009-11-01

Full Text Available MicroRNAs (miRNAs are small, non-coding RNAs that play essential roles in plant growth, development, and stress response. We conducted a genome-wide survey of maize miRNA genes, characterizing their structure, expression, and evolution. Computational approaches based on homology and secondary structure modeling identified 150 high-confidence genes within 26 miRNA families. For 25 families, expression was verified by deep-sequencing of small RNA libraries that were prepared from an assortment of maize tissues. PCR-RACE amplification of 68 miRNA transcript precursors, representing 18 families conserved across several plant species, showed that splice variation and the use of alternative transcriptional start and stop sites is common within this class of genes. Comparison of sequence variation data from diverse maize inbred lines versus teosinte accessions suggest that the mature miRNAs are under strong purifying selection while the flanking sequences evolve equivalently to other genes. Since maize is derived from an ancient tetraploid, the effect of whole-genome duplication on miRNA evolution was examined. We found that, like protein-coding genes, duplicated miRNA genes underwent extensive gene-loss, with approximately 35% of ancestral sites retained as duplicate homoeologous miRNA genes. This number is higher than that observed with protein-coding genes. A search for putative miRNA targets indicated bias towards genes in regulatory and metabolic pathways. As maize is one of the principal models for plant growth and development, this study will serve as a foundation for future research into the functional roles of miRNA genes.

Contrasting insect attraction and herbivore-induced plant volatile production in maize

Science.gov (United States)

Maize inbred line W22 is an important resource for genetic studies due to the availability of the UniformMu mutant population and a complete genome sequence. In this study, we assessed the suitability of W22 as a model for tritrophic interactions between maize, Spodoptera frugiperda (fall armyworm) ...

Evaluation of the reliability of maize reference assays for GMO quantification.

Science.gov (United States)

Papazova, Nina; Zhang, David; Gruden, Kristina; Vojvoda, Jana; Yang, Litao; Buh Gasparic, Meti; Blejec, Andrej; Fouilloux, Stephane; De Loose, Marc; Taverniers, Isabel

2010-03-01

A reliable PCR reference assay for relative genetically modified organism (GMO) quantification must be specific for the target taxon and amplify uniformly along the commercialised varieties within the considered taxon. Different reference assays for maize (Zea mays L.) are used in official methods for GMO quantification. In this study, we evaluated the reliability of eight existing maize reference assays, four of which are used in combination with an event-specific polymerase chain reaction (PCR) assay validated and published by the Community Reference Laboratory (CRL). We analysed the nucleotide sequence variation in the target genomic regions in a broad range of transgenic and conventional varieties and lines: MON 810 varieties cultivated in Spain and conventional varieties from various geographical origins and breeding history. In addition, the reliability of the assays was evaluated based on their PCR amplification performance. A single base pair substitution, corresponding to a single nucleotide polymorphism (SNP) reported in an earlier study, was observed in the forward primer of one of the studied alcohol dehydrogenase 1 (Adh1) (70) assays in a large number of varieties. The SNP presence is consistent with a poor PCR performance observed for this assay along the tested varieties. The obtained data show that the Adh1 (70) assay used in the official CRL NK603 assay is unreliable. Based on our results from both the nucleotide stability study and the PCR performance test, we can conclude that the Adh1 (136) reference assay (T25 and Bt11 assays) as well as the tested high mobility group protein gene assay, which also form parts of CRL methods for quantification, are highly reliable. Despite the observed uniformity in the nucleotide sequence of the invertase gene assay, the PCR performance test reveals that this target sequence might occur in more than one copy. Finally, although currently not forming a part of official quantification methods, zein and SSIIb

Identification and Characterization of microRNAs during Maize Grain Filling.

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Jin, Xining; Fu, Zhiyuan; Lv, Panqing; Peng, Qian; Ding, Dong; Li, Weihua; Tang, Jihua

2015-01-01

The grain filling rate is closely associated with final grain yield of maize during the period of maize grain filling. To identify the key microRNAs (miRNAs) and miRNA-dependent gene regulation networks of grain filling in maize, a deep-sequencing technique was used to research the dynamic expression patterns of miRNAs at four distinct developmental grain filling stages in Zhengdan 958, which is an elite hybrid and cultivated widely in China. The sequencing result showed that the expression amount of almost all miRNAs was changing with the development of the grain filling and formed in seven groups. After normalization, 77 conserved miRNAs and 74 novel miRNAs were co-detected in these four samples. Eighty-one out of 162 targets of the conserved miRNAs belonged to transcriptional regulation (81, 50%), followed by oxidoreductase activity (18, 11%), signal transduction (16, 10%) and development (15, 9%). The result showed that miRNA 156, 393, 396 and 397, with their respective targets, might play key roles in the grain filling rate by regulating maize growth, development and environment stress response. The result also offered novel insights into the dynamic change of miRNAs during the developing process of maize kernels and assisted in the understanding of how miRNAs are functioning about the grain filling rate.

The maize INDETERMINATE1 flowering time regulator defines a highly conserved zinc finger protein family in higher plants

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Colasanti Joseph

2006-06-01

Full Text Available Abstract Background The maize INDETERMINATE1 gene, ID1, is a key regulator of the transition to flowering and the founding member of a transcription factor gene family that encodes a protein with a distinct arrangement of zinc finger motifs. The zinc fingers and surrounding sequence make up the signature ID domain (IDD, which appears to be found in all higher plant genomes. The presence of zinc finger domains and previous biochemical studies showing that ID1 binds to DNA suggests that members of this gene family are involved in transcriptional regulation. Results Comparison of IDD genes identified in Arabidopsis and rice genomes, and all IDD genes discovered in maize EST and genomic databases, suggest that ID1 is a unique member of this gene family. High levels of sequence similarity amongst all IDD genes from maize, rice and Arabidopsis suggest that they are derived from a common ancestor. Several unique features of ID1 suggest that it is a divergent member of the maize IDD family. Although no clear ID1 ortholog was identified in the Arabidopsis genome, highly similar genes that encode proteins with identity extending beyond the ID domain were isolated from rice and sorghum. Phylogenetic comparisons show that these putative orthologs, along with maize ID1, form a group separate from other IDD genes. In contrast to ID1 mRNA, which is detected exclusively in immature leaves, several maize IDD genes showed a broad range of expression in various tissues. Further, Western analysis with an antibody that cross-reacts with ID1 protein and potential orthologs from rice and sorghum shows that all three proteins are detected in immature leaves only. Conclusion Comparative genomic analysis shows that the IDD zinc finger family is highly conserved among both monocots and dicots. The leaf-specific ID1 expression pattern distinguishes it from other maize IDD genes examined. A similar leaf-specific localization pattern was observed for the putative ID1 protein

The two capsid proteins of maize rayado fino virus contain common peptide sequences.

Science.gov (United States)

Falk, B W; Tsai, J H

1986-01-01

Virions of maize rayado fino virus (MRFV) were purified and two major capsid proteins (ca. Mr 29,000 and 22,000) were resolved by SDS-PAGE. When the two major capsid proteins were isolated from gels and compared by one-dimensional peptide mapping after digestion with Staphylococcus aureus V-8 protease, indistinguishable peptide maps were obtained, suggesting that these two proteins contain common peptide sequences. Some preparations also showed minor protein components that were intermediate between the Mr 22,000 and Mr 29,000 capsid proteins. One of the minor proteins, ca. Mr 27,000, gave a peptide map indistinguishable from the major capsid proteins. In vitro ageing of partially purified preparations or virion treatment with proteolytic enzymes failed to show conversion of the Mr 29,000 protein to a Mr 22,000. Protease inhibitors added to the buffers used for virion purification did not affect the apparent 1:3 ratio of 29,000 to 22,000 proteins in the purified preparations.

Expressed sequence tags related to nitrogen metabolism in maize inoculated with Azospirillum brasilense.

Science.gov (United States)

Pereira-Defilippi, L; Pereira, E M; Silva, F M; Moro, G V

2017-05-31

The relative quantitative real-time expression of two expressed sequence tags (ESTs) codifying for key enzymes in nitrogen metabolism in maize, nitrate reductase (ZmNR), and glutamine synthetase (ZmGln1-3) was performed for genotypes inoculated with Azospirillum brasilense. Two commercial single-cross hybrids (AG7098 and 2B707) and two experimental synthetic varieties (V2 and V4) were raised under controlled greenhouse conditions, in six treatment groups corresponding to different forms of inoculation and different levels of nitrogen application by top-dressing. The genotypes presented distinct responses to inoculation with A. brasilense. Increases in the expression of ZmNR were observed for the hybrids, while V4 only displayed a greater level of expression when the plants received nitrogenous fertilization by top-dressing and there was no inoculation. The expression of the ZmGln1-3EST was induced by A. brasilense in the hybrids and the variety V4. In contrast, the variety V2 did not respond to inoculation.

QTL MAPPING FOR GRAIN QUALITY TRAITS IN TESTCROSSES OF A MAIZE BIPARENTAL POPULATION USING GENOTYPING-BY-SEQUENCING DATA

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Mario Franić

2017-01-01

Full Text Available We performed QTL mapping in testcrosses of maize population IBMSyn4 for three grain quality traits: oil and protein contents and test weight. 191 phenotyped and genotyped lines were used as a training set while 85 genotyped only lines comprised a validation set used to calculate best linear unbiased predictions (BLUP, making a total of 276 phenotypes for the QTL analysis. 92000 filtered Genotyping-By-Sequencing (GBS SNP markers were used to calculate BLUPs, while a set of 2178 genetically mapped SSRs was used in QTL analysis. By simple QTL scan, we scored several minor effect QTLs: one for oil content (chromosome 1, one for protein content (chromosome 10 and four for test weight (chromosomes 1, 3, 5 and 10. QTLs associated with test weight were found to be additive, and 18.25% of phenotypic variance was explained by their joint effect. Only one QTL for test weight was found to be significant in composite interval mapping and it was mapped on chromosome 5. This QTL accounted for 9.97% of phenotypic variance. QTLs detected in this study represent monitoring of commercially most successful elite maize germplasm for grain quality traits.

Aflatoxins and fumonisin contamination of marketed maize, maize ...

African Journals Online (AJOL)

Aflatoxins and fumonisin contamination of marketed maize, maize bran and maize used as animal feed in northern ... PROMOTING ACCESS TO AFRICAN RESEARCH ... African Journal of Food, Agriculture, Nutrition and Development.

Chemical and nutritional values of maize and maize products ...

African Journals Online (AJOL)

Maize and maize products in selected grain markets within Kaduna, Nigeria, were obtained and investigated for proximate and mineral composition analysis using Atomic Absorption Spectrophotometer (AAS) and flame photometer. Proximate composition of maize and maize products were in the range of 11.6- 20 .0% ...

Characterization and expression of the maize β-carbonic anhydrase gene repeat regions.

Science.gov (United States)

Tems, Ursula; Burnell, James N

2010-12-01

In maize, carbonic anhydrase (CA; EC 4.2.1.1) catalyzes the first reaction of the C(4) photosynthetic pathway; it catalyzes the hydration of CO(2) to bicarbonate and provides an inorganic carbon source for the primary carboxylation reaction catalyzed by phosphoenolpyruvate (PEP) carboxylase. The β-CA isozymes from maize, as well as other agronomically important NADP-malic enzyme (NADP-ME) type C(4) crops, have remained relatively uncharacterized but differ significantly from the β-CAs of other C(4) monocot species primarily due to transcript length and the presence of repeat sequences. This research confirmed earlier findings of repeat sequences in maize CA transcripts, and demonstrated that the gene encoding these transcripts is also composed of repeat sequences. One of the maize CA genes was sequenced and found to encode two domains, with distinct groups of exons corresponding to the repeat regions of the transcript. We have also shown that expression of a single repeat region of the CA transcript produced active enzyme that associated as a dimer and was composed primarily of α-helices, consistent with that observed for other plant CAs. As the presence of repeat regions in the CA gene is unique to NADP-ME type C(4) monocot species, the implications of these findings in the context of the evolution of the location and function of this C(4) pathway enzyme are strongly suggestive of CA gene duplication resulting in an evolutionary advantage and a higher photosynthetic efficiency. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Development of maizeSNP3072, a high-throughput compatible SNP array, for DNA fingerprinting identification of Chinese maize varieties.

Science.gov (United States)

Tian, Hong-Li; Wang, Feng-Ge; Zhao, Jiu-Ran; Yi, Hong-Mei; Wang, Lu; Wang, Rui; Yang, Yang; Song, Wei

2015-01-01

Single nucleotide polymorphisms (SNPs) are abundant and evenly distributed throughout the maize ( Zea mays L.) genome. SNPs have several advantages over simple sequence repeats, such as ease of data comparison and integration, high-throughput processing of loci, and identification of associated phenotypes. SNPs are thus ideal for DNA fingerprinting, genetic diversity analysis, and marker-assisted breeding. Here, we developed a high-throughput and compatible SNP array, maizeSNP3072, containing 3072 SNPs developed from the maizeSNP50 array. To improve genotyping efficiency, a high-quality cluster file, maizeSNP3072_GT.egt, was constructed. All 3072 SNP loci were localized within different genes, where they were distributed in exons (43 %), promoters (21 %), 3' untranslated regions (UTRs; 22 %), 5' UTRs (9 %), and introns (5 %). The average genotyping failure rate using these SNPs was only 6 %, or 3 % using the cluster file to call genotypes. The genotype consistency of repeat sample analysis on Illumina GoldenGate versus Infinium platforms exceeded 96.4 %. The minor allele frequency (MAF) of the SNPs averaged 0.37 based on data from 309 inbred lines. The 3072 SNPs were highly effective for distinguishing among 276 examined hybrids. Comparative analysis using Chinese varieties revealed that the 3072SNP array showed a better marker success rate and higher average MAF values, evaluation scores, and variety-distinguishing efficiency than the maizeSNP50K array. The maizeSNP3072 array thus can be successfully used in DNA fingerprinting identification of Chinese maize varieties and shows potential as a useful tool for germplasm resource evaluation and molecular marker-assisted breeding.

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

Variability of geographically distinct isolates of maize rayado fino virus in Latin America.

Science.gov (United States)

Hammond, R W; Kogel, R; Ramirez, P

1997-12-01

We have examined the molecular epidemiology of the leafhopper-borne maize rayado fino virus (MRFV) in Latin America. The coat protein gene and 3' non-translated region of 14 isolates of MRFV collected from Latin America and the United States were sequenced and phylogenetic relationships examined. The nucleotide sequence revealed remarkable conservation, with a sequence similarity of 88-99%. Phylogenetic analysis of sequence data obtained from a 633 bp fragment showed that MRFV has diverged into three main clusters, i.e. the geographically distinct northern and southern isolates and the Colombian isolates. Significant differences between the isolates collected from Colombia, previously named maize rayado colombiana virus, based upon differences in symptomatology and serological relationships to MRFV, and the other MRFV isolates, provides additional evidence supporting its designation as a unique strain of MRFV.

Zebrafish ( Danio rerio) as a model for investigating the safety of GM feed ingredients (soya and maize); performance, stress response and uptake of dietary DNA sequences.

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Sissener, Nini H; Johannessen, Lene E; Hevrøy, Ernst M; Wiik-Nielsen, Christer R; Berdal, Knut G; Nordgreen, Andreas; Hemre, Gro-Ingunn

2010-01-01

A 20-d zebrafish (Danio rerio) feeding trial, in which a near doubling of fish weight was achieved, was conducted with GM feed ingredients to evaluate feed intake, growth, stress response and uptake of dietary DNA. A partial aim of the study was to assess zebrafish as a model organism in GM safety assessments. Roundup Ready soya (RRS), YieldGard Bt maize (MON810) and their non-modified, maternal, near-isogenic lines were used in a 2 x 2 factorial design. Soya variety and maize variety were the main factors, both with two levels; non-GM and GM. Compared with fish fed non-GM maize, those fed GM maize exhibited significantly better growth, had lower mRNA transcription levels of superoxide dismutase (SOD)-1 and a tendency (non-significant) towards lower transcription of heat shock protein 70 in liver. Sex of the fish and soya variety had significant interaction effects on total RNA yield from the whole liver and transcription of SOD-1, suggesting that some diet component affecting males and females differently was present in different levels in the GM and the non-GM soya used in the present study. Dietary DNA sequences were detected in all of the organs analysed, but not all of the samples. Soya and maize rubisco (non-transgenic, multicopy genes) were most frequently detected, while MON810 transgenic DNA fragments were detected in some samples and RRS fragments were not detected. In conclusion, zebrafish shows promise as a model for this application.

Detection of genetically modified maize in processed foods sold commercially in iran by qualitative PCR.

Science.gov (United States)

Rabiei, Maryam; Mehdizadeh, Mehrangiz; Rastegar, Hossein; Vahidi, Hossein; Alebouyeh, Mahmoud

2013-01-01

Detection of genetically modified organisms (GMOs) in food is an important issue for all the subjects involved in food control and customer's right. Due to the increasing number of GMOs imported to Iran during the past few years, it has become necessary to screen the products in order to determine the identity of the consumed daily foodstuffs. In this study, following the extraction of genomic DNA from processed foods sold commercially in Iran, qualitative PCR was performed to detect genetically modified maize. The recombinant DNA target sequences were detected with primers highly specific for each investigated transgene such as CaMV35s gene, Bt-11, MON810 and Bt-176 separately. Based on the gel electrophoresis results, Bt- 11 and MON810 events were detected in some maize samples, while, in none of them Bt- 176 modified gene was detected. For the first time, the results demonstrate the presence of genetically modified maize in Iranian food products, reinforcing the need for the development of labeling system and valid quantitative methods in routine analyses.

Resistance of maize varieties to the maize weevil Sitophilus zeamais

African Journals Online (AJOL)

This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize ...

Intercropping Maize With Legumes for Sustainable Highland Maize Production

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Adirek Punyalue

2018-02-01

Full Text Available Residue burning to prepare soil for maize growing deprives the soil of both protective cover and organic matter, and it exacerbates environmental issues such as Southeast Asia's haze problem. This paper reports on a study that evaluated the effectiveness of maize/legume intercropping as an alternative to maize cultivation with residue burning. Cowpea (Vigna unguiculata, mung bean (V. radiata, rice bean (V. umbellata, and lablab (Lablab purpureus were sown into a standing maize crop 30 days before harvest, and the results were compared with a maize crop grown using residue burning as the method for land preparation at Pang Da Agricultural Station in Chiang Mai, Thailand, in a replicated trial conducted over 3 growing seasons from 2012 to 2014. Intercropping increased maize grain yield by 31–53% and left 70–170% more residue containing 113–230% more nitrogen than the maize sown after residue burning, depending on the legume, and decreased weed dry weight by two-thirds after 2 seasons. Soil biodiversity was enriched by the intercrops, with a doubling in the spore density of arbuscular mycorrhizal fungi in the root-zone soil and increased abundance, diversity (Shannon index, and richness of the soil macrofauna. The abundance of soil animals increased with crop residue dry weight (r = 0.90, P < 0.05 and nitrogen content (r = 0.98, P < 0.01. The effect of intercropping on maize grain yield and accumulation of residue and nitrogen were then confirmed in a participatory experiment involving farmers in 2 highland villages in the Phrao and Chiang Dao districts of Chiang Mai Province with maize and rice bean in 2015. The effects of maize/legume intercropping—increased nitrogen accumulation and crop residue, enhanced soil biodiversity, suppression of weeds, and protection of the soil surface, which enabled the maize to be sown without land clearing with fire—should all contribute to sustainable highland maize production.

Genetic diversity among yellow maize with pro-vitamin A content

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Mercy Oluremi Olowolafe

2016-06-01

Full Text Available An improvement in the concentration of vitamin A in adapted yellow maize varieties grown in Africa can have a positive impact on the dietary intakes in regions where maize is a staple food. The present study was designed to identify heterotic groups and divergent parents for developing new pro-vitamin A enriched maize lines. Ten Simple Sequence Repeats (SSR markers were used to generate DNA profiles among thirteen commonly grown yellow maize lines across south western Nigeria and three high pro-vitamin A lines from International Institute of Tropical Agriculture (IITA, Ibadan. The result obtained estimated 100% polymorphism among the ten SSR markers with polymorphic information content that ranged from 0.28 to 0.71 on an average of 0.50. Genetic similarity coefficients among the 16 maize lines varied from 0.28 to 0.92 GS with an average of 0.63 GS. Four well defined groups were identified at 0.65 GS with an IITA line, PVA8, solely, formed a group. The study identified PVA8 and its most three distant relatives as potential divergent parents that could serve as important genetic resources for broadening the genetic base of the presently assessed IAR&T maize collections and also to develop new maize lines with higher level of pro-vitamin A content.

Display of a Maize cDNA library on baculovirus infected insect cells

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Jones Ian M

2008-08-01

Full Text Available Abstract Background Maize is a good model system for cereal crop genetics and development because of its rich genetic heritage and well-characterized morphology. The sequencing of its genome is well advanced, and new technologies for efficient proteomic analysis are needed. Baculovirus expression systems have been used for the last twenty years to express in insect cells a wide variety of eukaryotic proteins that require complex folding or extensive posttranslational modification. More recently, baculovirus display technologies based on the expression of foreign sequences on the surface of Autographa californica (AcMNPV have been developed. We investigated the potential of a display methodology for a cDNA library of maize young seedlings. Results We constructed a full-length cDNA library of young maize etiolated seedlings in the transfer vector pAcTMVSVG. The library contained a total of 2.5 × 105 independent clones. Expression of two known maize proteins, calreticulin and auxin binding protein (ABP1, was shown by western blot analysis of protein extracts from insect cells infected with the cDNA library. Display of the two proteins in infected insect cells was shown by selective biopanning using magnetic cell sorting and demonstrated proof of concept that the baculovirus maize cDNA display library could be used to identify and isolate proteins. Conclusion The maize cDNA library constructed in this study relies on the novel technology of baculovirus display and is unique in currently published cDNA libraries. Produced to demonstrate proof of principle, it opens the way for the development of a eukaryotic in vivo display tool which would be ideally suited for rapid screening of the maize proteome for binding partners, such as proteins involved in hormone regulation or defence.

Analysis of DNA methylation of maize in response to osmotic and salt stress based on methylation-sensitive amplified polymorphism.

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Tan, Ming-pu

2010-01-01

Water stress is known to alter cytosine methylation, which generally represses transcription. However, little is known about the role of methylation alteration in maize under osmotic stress. Here, methylation-sensitive amplified polymorphism (MSAP) was used to screen PEG- or NaCl-induced methylation alteration in maize seedlings. The sequences of 25 differentially amplified fragments relevant to stress were successfully obtained. Two stress-specific fragments from leaves, LP166 and LPS911, shown to be homologous to retrotransposon Gag-Pol protein genes, suggested that osmotic stress-induced methylation of retrotransposons. Three MSAP fragments, representing drought-induced or salt-induced methylation in leaves, were homologous to a maize aluminum-induced transporter. Besides these, heat shock protein HSP82, Poly [ADP-ribose] polymerase 2, Lipoxygenase, casein kinase (CK2), and dehydration-responsive element-binding (DREB) factor were also homologs of MSAP sequences from salt-treated roots. One MSAP fragment amplified from salt-treated roots, designated RS39, was homologous to the first intron of maize protein phosphatase 2C (zmPP2C), whereas - LS103, absent from salt-treated leaves, was homologous to maize glutathione S-transferases (zmGST). Expression analysis showed that salt-induced intron methylation of root zmPP2C significantly downregulated its expression, while salt-induced demethylation of leaf zmGST weakly upregulated its expression. The results suggested that salinity-induced methylation downregulated zmPP2C expression, a negative regulator of the stress response, while salinity-induced demethylation upregulated zmGST expression, a positive effecter of the stress response. Altered methylation, in response to stress, might also be involved in stress acclimation. Copyright 2009 Elsevier Masson SAS. All rights reserved.

Determinants of technical inefficiency among maize-based farming ...

African Journals Online (AJOL)

Examining the level of farm-specific technical inefficiency of maize-based farming households in Niger state of Nigeria, this study fitted cross-sectional data into a Cobb- Douglass production frontier. Data used for this study were obtained using structured questionnaire administered to 108 randomly selected maize-based ...

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identify novel genes expressed during vegetative, infectious, and reproductive growth

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Kema Gert HJ

2008-11-01

Full Text Available Abstract Background The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs from C. zeae-maydis and evaluate their expression during vegetative, infectious, and reproductive growth. Results A total of 27,551 ESTs was obtained from five cDNA libraries constructed from vegetative and sporulating cultures of C. zeae-maydis. The ESTs, grouped into 4088 clusters and 531 singlets, represented 4619 putative unique genes. Of these, 36% encoded proteins similar (E value ≤ 10-05 to characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions and biological processes based on Gene Ontology (GO classification. We identified numerous, previously undescribed genes with potential roles in photoreception, pathogenesis, and the regulation of development as well as Zephyr, a novel, actively transcribed transposable element. Differential expression of selected genes was demonstrated by real-time PCR, supporting their proposed roles in vegetative, infectious, and reproductive growth. Conclusion Novel genes that are potentially involved in regulating growth, development, and pathogenesis were identified in C. zeae-maydis, providing specific targets for characterization by molecular genetics and functional genomics. The EST data establish a foundation for future studies in evolutionary and comparative genomics among species of Cercospora and other groups of plant pathogenic fungi.

Molecular design of sequence specific DNA alkylating agents.

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Minoshima, Masafumi; Bando, Toshikazu; Shinohara, Ken-ichi; Sugiyama, Hiroshi

2009-01-01

Sequence-specific DNA alkylating agents have great interest for novel approach to cancer chemotherapy. We designed the conjugates between pyrrole (Py)-imidazole (Im) polyamides and DNA alkylating chlorambucil moiety possessing at different positions. The sequence-specific DNA alkylation by conjugates was investigated by using high-resolution denaturing polyacrylamide gel electrophoresis (PAGE). The results showed that polyamide chlorambucil conjugates alkylate DNA at flanking adenines in recognition sequences of Py-Im polyamides, however, the reactivities and alkylation sites were influenced by the positions of conjugation. In addition, we synthesized conjugate between Py-Im polyamide and another alkylating agent, 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI). DNA alkylation reactivies by both alkylating polyamides were almost comparable. In contrast, cytotoxicities against cell lines differed greatly. These comparative studies would promote development of appropriate sequence-specific DNA alkylating polyamides against specific cancer cells.

Testing potential effects of maize expressing the Bacillus thuringiensis Cry1Ab endotoxin (Bt maize) on mycorrhizal fungal communities via DNA- and RNA-based pyrosequencing and molecular fingerprinting.

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Verbruggen, Erik; Kuramae, Eiko E; Hillekens, Remy; de Hollander, Mattias; Kiers, E Toby; Röling, Wilfred F M; Kowalchuk, George A; van der Heijden, Marcel G A

2012-10-01

The cultivation of genetically modified (GM) crops has increased significantly over the last decades. However, concerns have been raised that some GM traits may negatively affect beneficial soil biota, such as arbuscular mycorrhizal fungi (AMF), potentially leading to alterations in soil functioning. Here, we test two maize varieties expressing the Bacillus thuringiensis Cry1Ab endotoxin (Bt maize) for their effects on soil AM fungal communities. We target both fungal DNA and RNA, which is new for AM fungi, and we use two strategies as an inclusive and robust way of detecting community differences: (i) 454 pyrosequencing using general fungal rRNA gene-directed primers and (ii) terminal restriction fragment length polymorphism (T-RFLP) profiling using AM fungus-specific markers. Potential GM-induced effects were compared to the normal natural variation of AM fungal communities across 15 different agricultural fields. AM fungi were found to be abundant in the experiment, accounting for 8% and 21% of total recovered DNA- and RNA-derived fungal sequences, respectively, after 104 days of plant growth. RNA- and DNA-based sequence analyses yielded most of the same AM fungal lineages. Our research yielded three major conclusions. First, no consistent differences were detected between AM fungal communities associated with GM plants and non-GM plants. Second, temporal variation in AMF community composition (between two measured time points) was bigger than GM trait-induced variation. Third, natural variation of AMF communities across 15 agricultural fields in The Netherlands, as well as within-field temporal variation, was much higher than GM-induced variation. In conclusion, we found no indication that Bt maize cultivation poses a risk for AMF.

[Contamination with genetically modified maize MON863 of processed foods on the market].

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Ohgiya, Yoko; Sakai, Masaaki; Miyashita, Taeko; Yano, Koichi

2009-06-01

Genetically modified maize MON863 (MON863), which has passed a safety examination in Japan, is commercially cultivated in the United States as a food and a resource for fuel. Maize is an anemophilous flower, which easily hybridizes. However, an official method for quantifying the content of MON863 has not been provided yet in Japan. We here examined MON863 contamination in maize-processed foods that had no labeling indicating of the use of genetically modified maize.From March 2006 to July 2008, we purchased 20 frozen maize products, 8 maize powder products, 7 canned maize products and 4 other maize processed foods. Three primer pairs named MON 863 primer, MON863-1, and M3/M4 for MON863-specific integrated cassette were used for qualitative polymerase chain reaction (PCR). A primer pair "SSIIb-3" for starch synthase gene was used to confirm the quality of extracted DNA. The starch synthase gene was detected in all samples. In qualitative tests, the MON863-specific fragments were detected in 7 (18%) maize powder products out of the 39 processed foods with all the three primer pairs.We concluded that various maize processed foods on the market were contaminated with MON863. It is important to accumulate further information on MON863 contamination in maize-processed foods that have no label indication of the use of genetically modified maize.

Status and prospects of maize research in Nepal

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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.

The sequence specificity of UV-induced DNA damage in a systematically altered DNA sequence.

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Khoe, Clairine V; Chung, Long H; Murray, Vincent

2018-06-01

The sequence specificity of UV-induced DNA damage was investigated in a specifically designed DNA plasmid using two procedures: end-labelling and linear amplification. Absorption of UV photons by DNA leads to dimerisation of pyrimidine bases and produces two major photoproducts, cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). A previous study had determined that two hexanucleotide sequences, 5'-GCTC*AC and 5'-TATT*AA, were high intensity UV-induced DNA damage sites. The UV clone plasmid was constructed by systematically altering each nucleotide of these two hexanucleotide sequences. One of the main goals of this study was to determine the influence of single nucleotide alterations on the intensity of UV-induced DNA damage. The sequence 5'-GCTC*AC was designed to examine the sequence specificity of 6-4PPs and the highest intensity 6-4PP damage sites were found at 5'-GTTC*CC nucleotides. The sequence 5'-TATT*AA was devised to investigate the sequence specificity of CPDs and the highest intensity CPD damage sites were found at 5'-TTTT*CG nucleotides. It was proposed that the tetranucleotide DNA sequence, 5'-YTC*Y (where Y is T or C), was the consensus sequence for the highest intensity UV-induced 6-4PP adduct sites; while it was 5'-YTT*C for the highest intensity UV-induced CPD damage sites. These consensus tetranucleotides are composed entirely of consecutive pyrimidines and must have a DNA conformation that is highly productive for the absorption of UV photons. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Assessment of genetic diversity among maize accessions using inter ...

African Journals Online (AJOL)

Assessment of genetic diversity among maize accessions using inter simple sequence repeats (ISSR) markers. AT do Amaral Júnior, EC de Oliveira, LSA Gonçalves, CA Scapim, LS Candido, TR da Conceição Silva, C Vittorazzi, KS da Cunha ...

Strategies for narrowing the maize yield gap of household farms through precision fertigation under irrigated conditions using CERES-Maize model.

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Liu, Jiangang; Wang, Guangyao; Chu, Qingquan; Chen, Fu

2017-07-01

Nitrogen (N) application significantly increases maize yield; however, the unreasonable use of N fertilizer is common in China. The analysis of crop yield gaps can reveal the limiting factors for yield improvement, but there is a lack of practical strategies for narrowing yield gaps of household farms. The objectives of this study were to assess the yield gap of summer maize using an integrative method and to develop strategies for narrowing the maize yield gap through precise N fertilization. The results indicated that there was a significant difference in maize yield among fields, with a low level of variation. Additionally, significant differences in N application rate were observed among fields, with high variability. Based on long-term simulation results, the optimal N application rate was 193 kg ha -1 , with a corresponding maximum attainable yield (AY max ) of 10 318 kg ha -1 . A considerable difference between farmers' yields and AY max was observed. Low agronomic efficiency of applied N fertilizer (AE N ) in farmers' fields was exhibited. The integrative method lays a foundation for exploring the specific factors constraining crop yield gaps at the field scale and for developing strategies for rapid site-specific N management. Optimization strategies to narrow the maize yield gap include increasing N application rates and adjusting the N application schedule. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Assessment of SCAR markers to design real-time PCR primers for rhizosphere quantification of Azospirillum brasilense phytostimulatory inoculants of maize.

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Couillerot, O; Poirier, M-A; Prigent-Combaret, C; Mavingui, P; Caballero-Mellado, J; Moënne-Loccoz, Y

2010-08-01

To assess the applicability of sequence characterized amplified region (SCAR) markers obtained from BOX, ERIC and RAPD fragments to design primers for real-time PCR quantification of the phytostimulatory maize inoculants Azospirillum brasilense UAP-154 and CFN-535 in the rhizosphere. Primers were designed based on strain-specific SCAR markers and were screened for successful amplification of target strain and absence of cross-reaction with other Azospirillum strains. The specificity of primers thus selected was verified under real-time PCR conditions using genomic DNA from strain collection and DNA from rhizosphere samples. The detection limit was 60 fg DNA with pure cultures and 4 x 10(3) (for UAP-154) and 4 x 10(4) CFU g(-1) (for CFN-535) in the maize rhizosphere. Inoculant quantification was effective from 10(4) to 10(8) CFU g(-1) soil. BOX-based SCAR markers were useful to find primers for strain-specific real-time PCR quantification of each A. brasilense inoculant in the maize rhizosphere. Effective root colonization is a prerequisite for successful Azospirillum phytostimulation, but cultivation-independent monitoring methods were lacking. The real-time PCR methods developed here will help understand the effect of environmental conditions on root colonization and phytostimulation by A. brasilense UAP-154 and CFN-535.

Sequence-specific DNA alkylation by tandem Py-Im polyamide conjugates.

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Taylor, Rhys Dylan; Kawamoto, Yusuke; Hashiya, Kaori; Bando, Toshikazu; Sugiyama, Hiroshi

2014-09-01

Tandem N-methylpyrrole-N-methylimidazole (Py-Im) polyamides with good sequence-specific DNA-alkylating activities have been designed and synthesized. Three alkylating tandem Py-Im polyamides with different linkers, which each contained the same moiety for the recognition of a 10 bp DNA sequence, were evaluated for their reactivity and selectivity by DNA alkylation, using high-resolution denaturing gel electrophoresis. All three conjugates displayed high reactivities for the target sequence. In particular, polyamide 1, which contained a β-alanine linker, displayed the most-selective sequence-specific alkylation towards the target 10 bp DNA sequence. The tandem Py-Im polyamide conjugates displayed greater sequence-specific DNA alkylation than conventional hairpin Py-Im polyamide conjugates (4 and 5). For further research, the design of tandem Py-Im polyamide conjugates could play an important role in targeting specific gene sequences. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Common histone modification code on C4 genes in maize and its conservation in Sorghum and Setaria italica.

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Heimann, Louisa; Horst, Ina; Perduns, Renke; Dreesen, Björn; Offermann, Sascha; Peterhansel, Christoph

2013-05-01

C4 photosynthesis evolved more than 60 times independently in different plant lineages. Each time, multiple genes were recruited into C4 metabolism. The corresponding promoters acquired new regulatory features such as high expression, light induction, or cell type-specific expression in mesophyll or bundle sheath cells. We have previously shown that histone modifications contribute to the regulation of the model C4 phosphoenolpyruvate carboxylase (C4-Pepc) promoter in maize (Zea mays). We here tested the light- and cell type-specific responses of three selected histone acetylations and two histone methylations on five additional C4 genes (C4-Ca, C4-Ppdk, C4-Me, C4-Pepck, and C4-RbcS2) in maize. Histone acetylation and nucleosome occupancy assays indicated extended promoter regions with regulatory upstream regions more than 1,000 bp from the transcription initiation site for most of these genes. Despite any detectable homology of the promoters on the primary sequence level, histone modification patterns were highly coregulated. Specifically, H3K9ac was regulated by illumination, whereas H3K4me3 was regulated in a cell type-specific manner. We further compared histone modifications on the C4-Pepc and C4-Me genes from maize and the homologous genes from sorghum (Sorghum bicolor) and Setaria italica. Whereas sorghum and maize share a common C4 origin, C4 metabolism evolved independently in S. italica. The distribution of histone modifications over the promoters differed between the species, but differential regulation of light-induced histone acetylation and cell type-specific histone methylation were evident in all three species. We propose that a preexisting histone code was recruited into C4 promoter control during the evolution of C4 metabolism.

Genome-wide identification of VQ motif-containing proteins and their expression profiles under abiotic stresses in maize

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Weibin eSong

2016-01-01

Full Text Available VQ motif-containing proteins play crucial roles in abiotic stress responses in plants. Recent studies have shown that some VQ proteins physically interact with WRKY transcription factors to activate downstream genes. In the present study, we identified and characterized genes encoding VQ motif-containing proteins using the most recent version of the maize genome sequence. In total, 61VQ genes were identified. In a cluster analysis, these genes clustered into nine groups together with their homologous genes in rice and Arabidopsis. Most of the VQ genes (57 out of 61 numbers identified in maize were found to be single-copy genes. Analyses of RNA-seq data obtained using seedlings under long-term drought treatment showed that the expression levels of most ZmVQ genes (41 out of 61 members changed during the drought stress response. Quantitative real-time PCR analyses showed that most of the ZmVQ genes were responsive to NaCl treatment. Also, approximately half of the ZmVQ genes were co-expressed with ZmWRKY genes. The identification of these VQ genes in the maize genome and knowledge of their expression profiles under drought and osmotic stresses will provide a solid foundation for exploring their specific functions in the abiotic stress responses of maize.

Genetic diversity of maize genotypes on the basis of morpho ...

African Journals Online (AJOL)

Genetic diversity of maize genotypes on the basis of morpho-physiological and simple sequence repeat (SSR) markers. Ashish Kumar, Arunita Rakshit, Naresh K Mangilipelli, Y Varalaxmi, T Vijayalakshmi, Jainender M Vanaja, SK Yadav, B Venkateswarlu, M Maheswari ...

Campbell's monkeys concatenate vocalizations into context-specific call sequences

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Ouattara, Karim; Lemasson, Alban; Zuberbühler, Klaus

2009-01-01

Primate vocal behavior is often considered irrelevant in modeling human language evolution, mainly because of the caller's limited vocal control and apparent lack of intentional signaling. Here, we present the results of a long-term study on Campbell's monkeys, which has revealed an unrivaled degree of vocal complexity. Adult males produced six different loud call types, which they combined into various sequences in highly context-specific ways. We found stereotyped sequences that were strongly associated with cohesion and travel, falling trees, neighboring groups, nonpredatory animals, unspecific predatory threat, and specific predator classes. Within the responses to predators, we found that crowned eagles triggered four and leopards three different sequences, depending on how the caller learned about their presence. Callers followed a number of principles when concatenating sequences, such as nonrandom transition probabilities of call types, addition of specific calls into an existing sequence to form a different one, or recombination of two sequences to form a third one. We conclude that these primates have overcome some of the constraints of limited vocal control by combinatorial organization. As the different sequences were so tightly linked to specific external events, the Campbell's monkey call system may be the most complex example of ‘proto-syntax’ in animal communication known to date. PMID:20007377

Genomic resources for gene discovery, functional genome annotation, and evolutionary studies of maize and its close relatives.

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Wang, Chao; Shi, Xue; Liu, Lin; Li, Haiyan; Ammiraju, Jetty S S; Kudrna, David A; Xiong, Wentao; Wang, Hao; Dai, Zhaozhao; Zheng, Yonglian; Lai, Jinsheng; Jin, Weiwei; Messing, Joachim; Bennetzen, Jeffrey L; Wing, Rod A; Luo, Meizhong

2013-11-01

Maize is one of the most important food crops and a key model for genetics and developmental biology. A genetically anchored and high-quality draft genome sequence of maize inbred B73 has been obtained to serve as a reference sequence. To facilitate evolutionary studies in maize and its close relatives, much like the Oryza Map Alignment Project (OMAP) (www.OMAP.org) bacterial artificial chromosome (BAC) resource did for the rice community, we constructed BAC libraries for maize inbred lines Zheng58, Chang7-2, and Mo17 and maize wild relatives Zea mays ssp. parviglumis and Tripsacum dactyloides. Furthermore, to extend functional genomic studies to maize and sorghum, we also constructed binary BAC (BIBAC) libraries for the maize inbred B73 and the sorghum landrace Nengsi-1. The BAC/BIBAC vectors facilitate transfer of large intact DNA inserts from BAC clones to the BIBAC vector and functional complementation of large DNA fragments. These seven Zea Map Alignment Project (ZMAP) BAC/BIBAC libraries have average insert sizes ranging from 92 to 148 kb, organellar DNA from 0.17 to 2.3%, empty vector rates between 0.35 and 5.56%, and genome equivalents of 4.7- to 8.4-fold. The usefulness of the Parviglumis and Tripsacum BAC libraries was demonstrated by mapping clones to the reference genome. Novel genes and alleles present in these ZMAP libraries can now be used for functional complementation studies and positional or homology-based cloning of genes for translational genomics.

Characterization and comparative analysis of the genome of Puccinia sorghi Schwein, the causal agent of maize common rust.

Science.gov (United States)

Rochi, Lucia; Diéguez, María José; Burguener, Germán; Darino, Martín Alejandro; Pergolesi, María Fernanda; Ingala, Lorena Romina; Cuyeu, Alba Romina; Turjanski, Adrián; Kreff, Enrique Domingo; Sacco, Francisco

2018-03-01

Rust fungi are one of the most devastating pathogens of crop plants. The biotrophic fungus Puccinia sorghi Schwein (Ps) is responsible for maize common rust, an endemic disease of maize (Zea mays L.) in Argentina that causes significant yield losses in corn production. In spite of this, the Ps genomic sequence was not available. We used Illumina sequencing to rapidly produce the 99.6Mbdraft genome sequence of Ps race RO10H11247, derived from a single-uredinial isolate from infected maize leaves collected in the Argentine Corn Belt Region during 2010. High quality reads were obtained from 200bppaired-end and 5000bpmate-paired libraries and assembled in 15,722 scaffolds. A pipeline which combined an ab initio program with homology-based models and homology to in planta enriched ESTs from four cereal pathogenic fungus (the three sequenced wheat rusts and Ustilago maydis) was used to identify 21,087 putative coding sequences, of which 1599 might be part of the Ps RO10H11247 secretome. Among the 458 highly conserved protein families from the euKaryotic Orthologous Groups (KOG) that occur in a wide range of eukaryotic organisms, 97.5% have at least one member with high homology in the Ps assembly (TBlastN, E-value⩽e-10) covering more than 50% of the length of the KOG protein. Comparative studies with the three sequenced wheat rust fungus, and microsynteny analysis involving Puccinia striiformis f. sp. tritici (Pst, wheat stripe rust fungus), support the quality achieved. The results presented here show the effectiveness of the Illumina strategy for sequencing dikaryotic genomes of non-model organisms and provides reliable DNA sequence information for genomic studies, including pathogenic mechanisms of this maize fungus and molecular marker design. Copyright © 2016 Elsevier Inc. All rights reserved.

An extended sequence specificity for UV-induced DNA damage.

Science.gov (United States)

Chung, Long H; Murray, Vincent

2018-01-01

The sequence specificity of UV-induced DNA damage was determined with a higher precision and accuracy than previously reported. UV light induces two major damage adducts: cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6-4)pyrimidone photoproducts (6-4PPs). Employing capillary electrophoresis with laser-induced fluorescence and taking advantages of the distinct properties of the CPDs and 6-4PPs, we studied the sequence specificity of UV-induced DNA damage in a purified DNA sequence using two approaches: end-labelling and a polymerase stop/linear amplification assay. A mitochondrial DNA sequence that contained a random nucleotide composition was employed as the target DNA sequence. With previous methodology, the UV sequence specificity was determined at a dinucleotide or trinucleotide level; however, in this paper, we have extended the UV sequence specificity to a hexanucleotide level. With the end-labelling technique (for 6-4PPs), the consensus sequence was found to be 5'-GCTC*AC (where C* is the breakage site); while with the linear amplification procedure, it was 5'-TCTT*AC. With end-labelling, the dinucleotide frequency of occurrence was highest for 5'-TC*, 5'-TT* and 5'-CC*; whereas it was 5'-TT* for linear amplification. The influence of neighbouring nucleotides on the degree of UV-induced DNA damage was also examined. The core sequences consisted of pyrimidine nucleotides 5'-CTC* and 5'-CTT* while an A at position "1" and C at position "2" enhanced UV-induced DNA damage. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Decomposition and fertilizing effects of maize stover and chromolaena odorata on maize yield

International Nuclear Information System (INIS)

Tetteh, F.M.; Safo, E.Y.; Quansah, C.

2008-01-01

The quality, rates of decomposition and the fertilizing effect of chromolaena odorata, and maize stover were determined in field experiments as surface application or buried in litter bags. Studies on the effect of plant materials of contrasting qualities (maize stover and C. odorata) applied sole (10 Mg ha -1 ) and mixed, on maize grain and biomass yield were also conducted on the Asuansi (Ferric Acrisol) soil series. Total nitrogen content of the residues ranged from 0.85% in maize stover to 3.50% in C. odorata. Organic carbon ranged from 34.90% in C. odorata to 48.50% in maize stover. Phosphorus ranged from 0.10% in maize stover to 0.76% in C. odorata. In the wet season, the decomposition rate constants (k) were 0.0319 day -1 for C. odorata, and 0.0081 for maize stover. In the dry season, the k values were 0.0083 for C. odorata, and 0.0072 day -1 for maize stover. Burying of the plant materials reduced the half-life (t 50 ) periods from 18 to 10 days for C. odorata, and 45 to 20 days for maize stover. Maize grain yield of 2556 kg ha -1 was obtained in sole C. odorata (10 Mg ha -1 ) compared with 2167 kg ha -1 for maize stover. Mixing of maize stover and C. odorata residues improved the nutrient content as well as nutrient release by the mixtures resulting in greater maize grain yields in the mixtures than the sole maize stover treatment. It is recommended that C. odorata be used as green manure, mulching or composting material to improve fertility. (au)

Classification of maize kernels using NIR hyperspectral imaging

DEFF Research Database (Denmark)

Williams, Paul; Kucheryavskiy, Sergey V.

2016-01-01

NIR hyperspectral imaging was evaluated to classify maize kernels of three hardness categories: hard, medium and soft. Two approaches, pixel-wise and object-wise, were investigated to group kernels according to hardness. The pixel-wise classification assigned a class to every pixel from individual...... and specificity of 0.95 and 0.93). Both feature extraction methods can be recommended for classification of maize kernels on production scale....

Advances in Maize Transformation Technologies and Development of Transgenic Maize.

Science.gov (United States)

Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K

2016-01-01

Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium -mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area.

Assessment of Genetic Diversity in Quality Protein Maize (QPM ...

African Journals Online (AJOL)

sriram

maize (QPM) lines using simple sequence repeat (SSR) markers. MSR Krishna1, S. Sokka Reddy2 and V. Chinna Babu Naik3. 1Department of Biotechnology, KL University, Vijayawada, AP, India. 2Institute of Biotechnology, College of Agriculture, Rajendranagar, Hyderabad, AP, India. 3Central Institute of Cotton Research ...

A Public Platform for the Verification of the Phenotypic Effect of Candidate Genes for Resistance to Aflatoxin Accumulation and Aspergillus flavus Infection in Maize

Directory of Open Access Journals (Sweden)

Xueyan Shan

2011-06-01

Full Text Available A public candidate gene testing pipeline for resistance to aflatoxin accumulation or Aspergillus flavus infection in maize is presented here. The pipeline consists of steps for identifying, testing, and verifying the association of selected maize gene sequences with resistance under field conditions. Resources include a database of genetic and protein sequences associated with the reduction in aflatoxin contamination from previous studies; eight diverse inbred maize lines for polymorphism identification within any maize gene sequence; four Quantitative Trait Loci (QTL mapping populations and one association mapping panel, all phenotyped for aflatoxin accumulation resistance and associated phenotypes; and capacity for Insertion/Deletion (InDel and SNP genotyping in the population(s for mapping. To date, ten genes have been identified as possible candidate genes and put through the candidate gene testing pipeline, and results are presented here to demonstrate the utility of the pipeline.

Detection of DNA of genetically modified maize by a silicon nanowire field-effect transistor

International Nuclear Information System (INIS)

Pham, Van Binh; Tung Pham, Xuan Thanh; Duong Dang, Ngoc Thuy; Tuyen Le, Thi Thanh; Tran, Phu Duy; Nguyen, Thanh Chien; Nguyen, Van Quoc; Dang, Mau Chien; Tong, Duy Hien; Van Rijn, Cees J M

2011-01-01

A silicon nanowire field-effect transistor based sensor (SiNW-FET) has been proved to be the most sensitive and powerful device for bio-detection applications. In this paper, SiNWs were first fabricated by using our recently developed deposition and etching under angle technique (DEA), then used to build up the complete SiNW device based biosensor. The fabricated SiNW biosensor was used to detect DNA of genetically modified maize. As the DNA of the genetically modified maize has particular DNA sequences of 35S promoter, we therefore designed 21 mer DNA oligonucleotides, which are used as a receptor to capture the transferred DNA of maize. In our work, the SiNW biosensor could detect DNA of genetically modified maize with concentrations down to about 200 pM

Hydroxylation of recombinant human collagen type I alpha 1 in transgenic maize co-expressed with a recombinant human prolyl 4-hydroxylase

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Pappu Kameshwari M

2011-06-01

Full Text Available Abstract Background Collagens require the hydroxylation of proline (Pro residues in their triple-helical domain repeating sequence Xaa-Pro-Gly to function properly as a main structural component of the extracellular matrix in animals at physiologically relevant conditions. The regioselective proline hydroxylation is catalyzed by a specific prolyl 4-hydroxylase (P4H as a posttranslational processing step. Results A recombinant human collagen type I α-1 (rCIα1 with high percentage of hydroxylated prolines (Hyp was produced in transgenic maize seeds when co-expressed with both the α- and β- subunits of a recombinant human P4H (rP4H. Germ-specific expression of rCIα1 using maize globulin-1 gene promoter resulted in an average yield of 12 mg/kg seed for the full-length rCIα1 in seeds without co-expression of rP4H and 4 mg/kg seed for the rCIα1 (rCIα1-OH in seeds with co-expression of rP4H. High-resolution mass spectrometry (HRMS analysis revealed that nearly half of the collagenous repeating triplets in rCIα1 isolated from rP4H co-expressing maize line had the Pro residues changed to Hyp residues. The HRMS analysis determined the Hyp content of maize-derived rCIα1-OH as 18.11%, which is comparable to the Hyp level of yeast-derived rCIα1-OH (17.47% and the native human CIa1 (14.59%, respectively. The increased Hyp percentage was correlated with a markedly enhanced thermal stability of maize-derived rCIα1-OH when compared to the non-hydroxylated rCIα1. Conclusions This work shows that maize has potential to produce adequately modified exogenous proteins with mammalian-like post-translational modifications that may be require for their use as pharmaceutical and industrial products.

Sequence-specific procedural learning deficits in children with specific language impairment.

Science.gov (United States)

Hsu, Hsinjen Julie; Bishop, Dorothy V M

2014-05-01

This study tested the procedural deficit hypothesis of specific language impairment (SLI) by comparing children's performance in two motor procedural learning tasks and an implicit verbal sequence learning task. Participants were 7- to 11-year-old children with SLI (n = 48), typically developing age-matched children (n = 20) and younger typically developing children matched for receptive grammar (n = 28). In a serial reaction time task, the children with SLI performed at the same level as the grammar-matched children, but poorer than age-matched controls in learning motor sequences. When tested with a motor procedural learning task that did not involve learning sequential relationships between discrete elements (i.e. pursuit rotor), the children with SLI performed comparably with age-matched children and better than younger grammar-matched controls. In addition, poor implicit learning of word sequences in a verbal memory task (the Hebb effect) was found in the children with SLI. Together, these findings suggest that SLI might be characterized by deficits in learning sequence-specific information, rather than generally weak procedural learning. © 2014 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

Net Farm Income Analysis of Maize Production in Gwagwalada Area ...

African Journals Online (AJOL)

Net Farm Income Analysis of Maize Production in Gwagwalada Area Council of Federal Capital Territory, Nigeria. OO Alabi, AAA Coker, ME Idegbesor. Abstract. This study examined net farm income of maize production in Gwagwalada Area Council of Federal Capital Territory. The specific objectives are to: identify the ...

Comparison of species composition and fumonisin production in Aspergillus section Nigri populations in maize kernels from USA and Italy.

Science.gov (United States)

Susca, Antonia; Moretti, Antonio; Stea, Gaetano; Villani, Alessandra; Haidukowski, Miriam; Logrieco, Antonio; Munkvold, Gary

2014-10-01

Fumonisin contamination of maize is considered a serious problem in most maize-growing regions of the world, due to the widespread occurrence of these mycotoxins and their association with toxicosis in livestock and humans. Fumonisins are produced primarily by species of Fusarium that are common in maize grain, but also by some species of Aspergillus sect. Nigri, which can also occur on maize kernels as opportunistic pathogens. Understanding the origin of fumonisin contamination in maize is a key component in developing effective management strategies. Although some fungi in Aspergillus sect. Nigri are known to produce fumonisins, little is known about the species which are common in maize and whether they make a measurable contribution to fumonisin contamination of maize grain. In this work, we evaluated populations of Aspergillus sect. Nigri isolated from maize in USA and Italy, focusing on analysis of housekeeping genes, the fum8 gene and in vitro capability of producing fumonisins. DNA sequencing was used to identify Aspergillus strains belonging to sect. Nigri, in order to compare species composition between the two populations, which might influence specific mycotoxicological risks. Combined beta-tubulin/calmodulin sequences were used to genetically characterize 300 strains (199 from Italy and 101 from USA) which grouped into 4 clades: Aspergillus welwitschiae (syn. Aspergillus awamori, 14.7%), Aspergillus tubingensis (37.0%) and Aspergillus niger group 1 (6.7%) and group 2 (41.3%). Only one strain was identified as Aspergillus carbonarius. Species composition differed between the two populations; A. niger predominated among the USA isolates (69%), but comprised a smaller percentage (38%) of Italian isolates. Conversely, A. tubingensis and A. welwitschiae occurred at higher frequencies in the Italian population (42% and 20%, respectively) than in the USA population (27% and 5%). The evaluation of FB2 production on CY20S agar revealed 118 FB2 producing and 84

Coordination of the maize transcriptome by a conserved circadian clock

Directory of Open Access Journals (Sweden)

Harmon Frank G

2010-06-01

Full Text Available Abstract Background The plant circadian clock orchestrates 24-hour rhythms in internal physiological processes to coordinate these activities with daily and seasonal changes in the environment. The circadian clock has a profound impact on many aspects of plant growth and development, including biomass accumulation and flowering time. Despite recent advances in understanding the circadian system of the model plant Arabidopsis thaliana, the contribution of the circadian oscillator to important agronomic traits in Zea mays and other cereals remains poorly defined. To address this deficit, this study investigated the transcriptional landscape of the maize circadian system. Results Since transcriptional regulation is a fundamental aspect of circadian systems, genes exhibiting circadian expression were identified in the sequenced maize inbred B73. Of the over 13,000 transcripts examined, approximately 10 percent displayed circadian expression patterns. The majority of cycling genes had peak expression at subjective dawn and dusk, similar to other plant circadian systems. The maize circadian clock organized co-regulation of genes participating in fundamental physiological processes, including photosynthesis, carbohydrate metabolism, cell wall biogenesis, and phytohormone biosynthesis pathways. Conclusions Circadian regulation of the maize genome was widespread and key genes in several major metabolic pathways had circadian expression waveforms. The maize circadian clock coordinated transcription to be coincident with oncoming day or night, which was consistent with the circadian oscillator acting to prepare the plant for these major recurring environmental changes. These findings highlighted the multiple processes in maize plants under circadian regulation and, as a result, provided insight into the important contribution this regulatory system makes to agronomic traits in maize and potentially other C4 plant species.

Sequence analysis of cereal sucrose synthase genes and isolation ...

African Journals Online (AJOL)

SERVER

2007-10-18

Oct 18, 2007 ... sequencing of sucrose synthase gene fragment from sor- ghum using primers designed at their conserved exons. MATERIALS AND METHODS. Multiple sequence alignment. Sucrose synthase gene sequences of various cereals like rice, maize, and barley were accessed from NCBI Genbank database.

Maize kernel evolution:From teosinte to maize

Science.gov (United States)

Maize is the most productive and highest value commodity in the US and around the world: over 1 billion tons were produced each year in 2013 and 2014. Together, maize, rice and wheat comprise over 60% of the world’s caloric intake, with wide regional variability in the importance of each crop. The i...

Incorporating a water-logging routine into CERES-Maize, and some ...

African Journals Online (AJOL)

The inability of CERES-Maize v3.0 to simulate a fluctuating water table has been identified as a major constraint in using this particular model in South Africa and in Kenya. Information regarding fluctuating water tables under specific conditions, and their influence on maize production, has been presented in South African ...

TCUP: A novel hAT transposon active in maize tissue culture

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Alan eSmith

2012-01-01

Full Text Available Transposable elements are capable of inducing heritable de novo genetic variation. The sequences capable of reactivation, and environmental factors that induce mobilization, remain poorly defined even in well-studied genomes such as maize. We treated maize tissue culture with the demethylating agent 5-aza-2-deoxcytidine and examined long-term tissue culture lines to discover silenced transposable elements that have the potential to induce heritable genetic variation. Through these screens we have identified a novel low copy number hAT transposon, Tissue Culture Up-Regulated (TCUP, which is transcribed at high levels in long-term maize Black Mexican Sweet (BMS tissue culture and up-regulated in response to treatment with 5-aza-2-deoxycytidine. Analysis of the TIGR Maize Gene Index revealed that this element is the most frequently represented EST from the BMS cell culture library and is not represented in other tissue libraries, which is the basis for its name. A full-length sequence was assembled in inbred B73 that contains the putative functional motifs required for autonomous movement of a hAT transposon. Transposon display detected movement of TCUP in two long-term tissue cultured cell lines of the genotype Hi-II AxB and BMS. This research implicates TCUP as a transposon that is capable of reactivation and which may also be particularly sensitive to the stress of the tissue culture environment. Our findings are consistent with the hypothesis that epigenetic alterations potentiate genomic responses to stress during clonal propagation of plants.

Harnessing maize biodiversity

Science.gov (United States)

Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

A Common Histone Modification Code on C4 Genes in Maize and Its Conservation in Sorghum and Setaria italica1[W][OA

Science.gov (United States)

Heimann, Louisa; Horst, Ina; Perduns, Renke; Dreesen, Björn; Offermann, Sascha; Peterhansel, Christoph

2013-01-01

C4 photosynthesis evolved more than 60 times independently in different plant lineages. Each time, multiple genes were recruited into C4 metabolism. The corresponding promoters acquired new regulatory features such as high expression, light induction, or cell type-specific expression in mesophyll or bundle sheath cells. We have previously shown that histone modifications contribute to the regulation of the model C4 phosphoenolpyruvate carboxylase (C4-Pepc) promoter in maize (Zea mays). We here tested the light- and cell type-specific responses of three selected histone acetylations and two histone methylations on five additional C4 genes (C4-Ca, C4-Ppdk, C4-Me, C4-Pepck, and C4-RbcS2) in maize. Histone acetylation and nucleosome occupancy assays indicated extended promoter regions with regulatory upstream regions more than 1,000 bp from the transcription initiation site for most of these genes. Despite any detectable homology of the promoters on the primary sequence level, histone modification patterns were highly coregulated. Specifically, H3K9ac was regulated by illumination, whereas H3K4me3 was regulated in a cell type-specific manner. We further compared histone modifications on the C4-Pepc and C4-Me genes from maize and the homologous genes from sorghum (Sorghum bicolor) and Setaria italica. Whereas sorghum and maize share a common C4 origin, C4 metabolism evolved independently in S. italica. The distribution of histone modifications over the promoters differed between the species, but differential regulation of light-induced histone acetylation and cell type-specific histone methylation were evident in all three species. We propose that a preexisting histone code was recruited into C4 promoter control during the evolution of C4 metabolism. PMID:23564230

Multiple Pesticides Detoxification Function of Maize (Zea mays) GST34.

Science.gov (United States)

Li, Dongzhi; Xu, Li; Pang, Sen; Liu, Zhiqian; Zhao, Weisong; Wang, Chengju

2017-03-08

ZmGST34 is a maize Tau class GST gene and was found to be differently expressed between two maize cultivars differing in tolerance to herbicide metolachlor. To explore the possible role of ZmGST34 in maize development, the expression pattern and substrate specificity of ZmGST34 were characterized by quantitative RT-PCR and heterologous expression system, respectively. The results indicated that the expression level of ZmGST34 was increased ∼2-5-fold per day during the second-leaf stage of maize seedling. Chloroacetanilide herbicides or phytohormone treatments had no influence on the expression level of ZmGST34, suggesting that ZmGST34 is a constitutively expressed gene in maize seedling. Heterologous expression in Escherichia coli and in Arabidopsis thaliana proved that ZmGST34 can metabolize most chloroacetanilide herbicides and increase tolerance to these herbicides in transgenic Arabidopsis thaliana. The constitutive expression pattern and broad substrate activity of ZmGST34 suggested that this gene may play an important role in maize development in addition to the detoxification of pesticides.

Predicting tissue-specific expressions based on sequence characteristics

KAUST Repository

Paik, Hyojung; Ryu, Tae Woo; Heo, Hyoungsam; Seo, Seungwon; Lee, Doheon; Hur, Cheolgoo

2011-01-01

In multicellular organisms, including humans, understanding expression specificity at the tissue level is essential for interpreting protein function, such as tissue differentiation. We developed a prediction approach via generated sequence features from overrepresented patterns in housekeeping (HK) and tissue-specific (TS) genes to classify TS expression in humans. Using TS domains and transcriptional factor binding sites (TFBSs), sequence characteristics were used as indices of expressed tissues in a Random Forest algorithm by scoring exclusive patterns considering the biological intuition; TFBSs regulate gene expression, and the domains reflect the functional specificity of a TS gene. Our proposed approach displayed better performance than previous attempts and was validated using computational and experimental methods.

Predicting tissue-specific expressions based on sequence characteristics

KAUST Repository

Paik, Hyojung

2011-04-30

In multicellular organisms, including humans, understanding expression specificity at the tissue level is essential for interpreting protein function, such as tissue differentiation. We developed a prediction approach via generated sequence features from overrepresented patterns in housekeeping (HK) and tissue-specific (TS) genes to classify TS expression in humans. Using TS domains and transcriptional factor binding sites (TFBSs), sequence characteristics were used as indices of expressed tissues in a Random Forest algorithm by scoring exclusive patterns considering the biological intuition; TFBSs regulate gene expression, and the domains reflect the functional specificity of a TS gene. Our proposed approach displayed better performance than previous attempts and was validated using computational and experimental methods.

Diversification, phylogeny and evolution of auxin response factor (ARF) family: insights gained from analyzing maize ARF genes.

Science.gov (United States)

Wang, Yijun; Deng, Dexiang; Shi, Yating; Miao, Nan; Bian, Yunlong; Yin, Zhitong

2012-03-01

Auxin response factors (ARFs), member of the plant-specific B3 DNA binding superfamily, target specifically to auxin response elements (AuxREs) in promoters of primary auxin-responsive genes and heterodimerize with Aux/IAA proteins in auxin signaling transduction cascade. In previous research, we have isolated and characterized maize Aux/IAA genes in whole-genome scale. Here, we report the comprehensive analysis of ARF genes in maize. A total of 36 ARF genes were identified and validated from the B73 maize genome through an iterative strategy. Thirty-six maize ARF genes are distributed in all maize chromosomes except chromosome 7. Maize ARF genes expansion is mainly due to recent segmental duplications. Maize ARF proteins share one B3 DNA binding domain which consists of seven-stranded β sheets and two short α helixes. Twelve maize ARFs with glutamine-rich middle regions could be as activators in modulating expression of auxin-responsive genes. Eleven maize ARF proteins are lack of homo- and heterodimerization domains. Putative cis-elements involved in phytohormones and light signaling responses, biotic and abiotic stress adaption locate in promoters of maize ARF genes. Expression patterns vary greatly between clades and sister pairs of maize ARF genes. The B3 DNA binding and auxin response factor domains of maize ARF proteins are primarily subjected to negative selection during selective sweep. The mixed selective forces drive the diversification and evolution of genomic regions outside of B3 and ARF domains. Additionally, the dicot-specific proliferation of ARF genes was detected. Comparative genomics analysis indicated that maize, sorghum and rice duplicate chromosomal blocks containing ARF homologs are highly syntenic. This study provides insights into the distribution, phylogeny and evolution of ARF gene family.

Improved evidence-based genome-scale metabolic models for maize leaf, embryo, and endosperm

Energy Technology Data Exchange (ETDEWEB)

Seaver, Samuel M. D.; Bradbury, Louis M. T.; Frelin, Océane; 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.

Genome-wide identification, classification and expression profiling of nicotianamine synthase (NAS) gene family in maize

OpenAIRE

Zhou, Xiaojin; Li, Suzhen; Zhao, Qianqian; Liu, Xiaoqing; Zhang, Shaojun; Sun, Cheng; Fan, Yunliu; Zhang, Chunyi; Chen, Rumei

2013-01-01

Background Nicotianamine (NA), a ubiquitous molecule in plants, is an important metal ion chelator and the main precursor for phytosiderophores biosynthesis. Considerable progress has been achieved in cloning and characterizing the functions of nicotianamine synthase (NAS) in plants including barley, Arabidopsis and rice. Maize is not only an important cereal crop, but also a model plant for genetics and evolutionary study. The genome sequencing of maize was completed, and many gene families ...

Characterization of genetic diversity and linkage disequilibrium of ZmLOX4 and ZmLOX5 loci in maize.

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Gerald N De La Fuente

Full Text Available Maize (Zea mays L. lipoxygenases (ZmLOXs are well recognized as important players in plant defense against pathogens, especially in cross kingdom lipid communication with pathogenic fungi. This study is among the first to investigate genetic diversity at important gene paralogs ZmLOX4 and ZmLOX5. Sequencing of these genes in 400 diverse maize lines showed little genetic diversity and low linkage disequilibrium in the two genes. Importantly, we identified one inbred line in which ZmLOX5 has a disrupted open reading frame, a line missing ZmLOX5, and five lines with a duplication of ZmLOX5. Tajima's D test suggests that both ZmLOX4 and ZmLOX5 have been under neutral selection. Further investigation of haplotype data revealed that within the ZmLOX family members only ZmLOX12, a monocot specific ZmLOX, showed strong linkage disequilibrium that extends further than expected in maize. Linkage disequilibrium patterns at these loci of interest are crucial for future candidate gene association mapping studies. ZmLOX4 and ZmLOX5 mutations and copy number variants are under further investigation for crop improvement.

Biological and molecular characterization of a putative new sobemovirus infecting Imperata cylindrica and maize in Africa.

Science.gov (United States)

Sérémé, Drissa; Lacombe, Séverine; Konaté, Moumouni; Pinel-Galzi, Agnès; Traoré, Valentin Stanislas Edgar; Hébrard, Eugénie; Traoré, Oumar; Brugidou, Christophe; Fargette, Denis; Konaté, Gnissa

2008-01-01

A new virus was isolated from both the grass Imperata cylindrica and maize plants that had yellow mottle symptoms in Burkina Faso, West Africa. The virus has isometric particles ca. 32 nm in diameter. The experimental host range was restricted to Rottboellia exaltata. Virions were isolated from leaves of systemically infected maize plants. Koch's postulates were completed by mechanically inoculating uninfected Imperata or maize with either purified virus or sap from infected Imperata plants. Virion preparations were used to produce a specific polyclonal antiserum, and an enzyme-linked immunosorbent assay test was set up. The full genome of the virus was sequenced, and it comprised 4,547 nucleotides. Phylogenetic studies indicated that the virus is closely related to rice yellow mottle virus, a sobemovirus that infects monocotyledons in Africa, and is more distantly related to cocksfoot mottle virus, another sobemovirus that infects monocotyledons. Although the virus can infect R. exaltata experimentally, it differs from Rottboellia yellow mottle virus, a member of a tentative species of the genus Sobemovirus that also infects monocotyledons in Africa. Particle morphology, serological properties, genomic organization, and phylogenetic analysis are all consistent with assignment of the new virus to the genus Sobemovirus. The name Imperata yellow mottle virus is proposed.

Propiconazole is a specific and accessible brassinosteroid (BR) biosynthesis inhibitor for Arabidopsis and maize.

Science.gov (United States)

Hartwig, Thomas; Corvalan, Claudia; Best, Norman B; Budka, Joshua S; Zhu, Jia-Ying; Choe, Sunghwa; Schulz, Burkhard

2012-01-01

Brassinosteroids (BRs) are steroidal hormones that play pivotal roles during plant development. In addition to the characterization of BR deficient mutants, specific BR biosynthesis inhibitors played an essential role in the elucidation of BR function in plants. However, high costs and limited availability of common BR biosynthetic inhibitors constrain their key advantage as a species-independent tool to investigate BR function. We studied propiconazole (Pcz) as an alternative to the BR inhibitor brassinazole (Brz). Arabidopsis seedlings treated with Pcz phenocopied BR biosynthetic mutants. The steady state mRNA levels of BR, but not gibberellic acid (GA), regulated genes increased proportional to the concentrations of Pcz. Moreover, root inhibition and Pcz-induced expression of BR biosynthetic genes were rescued by 24epi-brassinolide, but not by GA(3) co-applications. Maize seedlings treated with Pcz showed impaired mesocotyl, coleoptile, and true leaf elongation. Interestingly, the genetic background strongly impacted the tissue specific sensitivity towards Pcz. Based on these findings we conclude that Pcz is a potent and specific inhibitor of BR biosynthesis and an alternative to Brz. The reduced cost and increased availability of Pcz, compared to Brz, opens new possibilities to study BR function in larger crop species.

A maize resistance gene functions against bacterial streak disease in rice.

Science.gov (United States)

Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

2005-10-25

Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, which causes bacterial streak disease. Bacterial streak is an important disease of rice in Asia, and no simply inherited sources of resistance have been identified in rice. Although X. o. pv. oryzicola does not cause disease on maize, we identified a maize gene, Rxo1, that conditions a resistance reaction to a diverse collection of pathogen strains. Surprisingly, Rxo1 also controls resistance to the unrelated pathogen Burkholderia andropogonis, which causes bacterial stripe of sorghum and maize. The same gene thus controls resistance reactions to both pathogens and nonpathogens of maize. Rxo1 has a nucleotide-binding site-leucine-rich repeat structure, similar to many previously identified R genes. Most importantly, Rxo1 functions after transfer as a transgene to rice, demonstrating the feasibility of nonhost R gene transfer between cereals and providing a valuable tool for controlling bacterial streak disease.

Species of Cercospora associated with grey leaf spot of maize

NARCIS (Netherlands)

Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

Species of Cercospora associated with grey leaf spot of maize.

NARCIS (Netherlands)

Crous, P.W.; Groenewald, J.Z.; Groenewald, M.; Caldwell, P.; Braun, U.; Harrington, T.C.

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the

The effect of Zn, N and P application on nutrient uptake in wheat-maize sequence using isotopic techniques

International Nuclear Information System (INIS)

Tehrani, M.M.; Sachdev, P.; Sachdev, M.S.

2006-01-01

A pot experiment was conducted at the Nuclear Research Laboratory , Indian Agricultural Research Institute, New Delhi in 2000-2001. The experiment was 3x3x3 factorial in Completely Randomized Design (CRD) with three replications. Fertilizers were applied as three levels of zinc 0. 2.5 and 5 mg Zn kg -1 as ZnSO 4 , three levels of phosphorus 0, 7.5 and 15 mg P kg -1 through KH 2 PO 4 and three levels of nitrogen 30, 60 and 90 mg N kg -1 as urea. Zn fertilizer was not applied for the second crop in sequence. The amount of available Zn in soil decreased by the application of P and N, but increased by the Zn application. The P application increased the available pool of P in soil, but the zinc levels had no effect on it. Data revealed that the P application decreased the Zn concentration in plant tissue for both the crops. The per cent N utilization decreased drastically with increasing rate of N application from N 30 to N 90 in wheat. The highest level of P application resulted in least total Zn uptake, per cent Zndff, fertilizer Zn uptake and per cent Zn utilized from fertilizer. The no zinc application showed the highest value of Zn application to the wheat crop. The highest values of total P uptake, per cent Pdff, fertilizer uptake and per cent P utilized from fertilizer in the succeeding crop of maize were observed with residual effect of Zn 5 among three levels of Zn application to the first crop of maize. (author)

Maize MeJA-responsive proteins identified by high-resolution 2-DE PAGE

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Yuliang Zhang

2015-12-01

Full Text Available Exogenous methyl jasmonate (MeJA is well-known to induce plant defense mechanisms effective against a wide variety of insect and microbial pests. High-resolution 2-DE gel electrophoresis was used to discover changes in the leaf proteome of maize exposed to MeJA. We sequenced 62 MeJA-responsive proteins by tandem mass spectroscopy, and deposited the mass spectra and identities in the EMBL-EBI PRIDE repository under reference number PXD001793. An analysis and discussion of the identified proteins in relation to maize defense against Asian corn borer is published by Zhang et al. (2015 [1].

Sporophytic control of pollen tube growth and guidance in maize

Science.gov (United States)

Lausser, Andreas; Kliwer, Irina; Srilunchang, Kanok-orn; Dresselhaus, Thomas

2010-01-01

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 μm 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. PMID:19926683

Dynamic epigenetic states of maize centromeres

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Yalin eLiu

2015-10-01

Full Text Available The centromere is a specialized chromosomal region identified as the major constriction, upon which the kinetochore complex is formed, ensuring accurate chromosome orientation and segregation during cell division. The rapid evolution of centromere DNA sequence and the conserved centromere function are two contradictory aspects of centromere biology. Indeed, the sole presence of genetic sequence is not sufficient for centromere formation. Various dicentric chromosomes with one inactive centromere have been recognized. It has also been found that de novo centromere formation is common on fragments in which centromeric DNA sequences are lost. Epigenetic factors play important roles in centromeric chromatin assembly and maintenance. Nondisjunction of the supernumerary B chromosome early prophase of meiosis I requires an active centromere. This review discusses recent studies in maize about genetic and epigenetic elements regulating formation and maintenance of centromere chromatin, as well as centromere behavior in meiosis.

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...

Risk Adjusted Production Efficiency of Maize Farmers in Ethiopia: Implication for Improved Maize Varieties Adoption

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Sisay Diriba Lemessa

2017-09-01

Full Text Available This study analyzes the technical efficiency and production risk of 862 maize farmers in major maize producing regions of Ethiopia. It employs the stochastic frontier approach (SFA to estimate the level of technical efficiencies of stallholder farmers. The stochastic frontier approach (SFA uses flexible risk properties to account for production risk. Thus, maize production variability is assessed from two perspectives, the production risk and the technical efficiency. The study also attempts to determine the socio-economic and farm characteristics that influence technical efficiency of maize production in the study area. The findings of the study showed the existence of both production risk and technical inefficiency in maize production process. Input variables (amounts per hectare such as fertilizer and labor positively influence maize output. The findings also show that farms in the study area exhibit decreasing returns to scale. Fertilizer and ox plough days reduce output risk while labor and improved seed increase output risk. The mean technical efficiency for maize farms is 48 percent. This study concludes that production risk and technical inefficiency prevents the maize farmers from realizing their frontier output. The best factors that improve the efficiency of the maize farmers in the study area include: frequency of extension contact, access to credit and use of intercropping. It was also realized that altitude and terracing in maize farms had influence on farmer efficiency.

NS maize hybrids in production regions of Serbia

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Stojaković Milisav

2010-01-01

Full Text Available Fifteen NS maize hybrids of FAO 300-700 maturity groups were evaluated in strip trials (plot size 1,120 m2 at 30 locations in Serbia. In all locations including all production regions, the most yielding hybrid was NS 6030 with average yield of 10.9 t ha-1. The additive Main Effects and Multiplicative Interaction (AMMI and the sites regression (SREG models were used to study basic structure of G x E interactions and the possible existence of different mega-environments in Serbian maize growing regions in 2009. The results of the 15 hybrids x 10 locations for grain yield in maize showed by biplot technique indicate several specific location-hybrid deviations (the AMMI biplot, and possible existence of at least one mega-environment (the GGE biplot. .

Sequence-specific bias correction for RNA-seq data using recurrent neural networks.

Science.gov (United States)

Zhang, Yao-Zhong; Yamaguchi, Rui; Imoto, Seiya; Miyano, Satoru

2017-01-25

The recent success of deep learning techniques in machine learning and artificial intelligence has stimulated a great deal of interest among bioinformaticians, who now wish to bring the power of deep learning to bare on a host of bioinformatical problems. Deep learning is ideally suited for biological problems that require automatic or hierarchical feature representation for biological data when prior knowledge is limited. In this work, we address the sequence-specific bias correction problem for RNA-seq data redusing Recurrent Neural Networks (RNNs) to model nucleotide sequences without pre-determining sequence structures. The sequence-specific bias of a read is then calculated based on the sequence probabilities estimated by RNNs, and used in the estimation of gene abundance. We explore the application of two popular RNN recurrent units for this task and demonstrate that RNN-based approaches provide a flexible way to model nucleotide sequences without knowledge of predetermined sequence structures. Our experiments show that training a RNN-based nucleotide sequence model is efficient and RNN-based bias correction methods compare well with the-state-of-the-art sequence-specific bias correction method on the commonly used MAQC-III data set. RNNs provides an alternative and flexible way to calculate sequence-specific bias without explicitly pre-determining sequence structures.

From many, one: genetic control of prolificacy during maize domestication.

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David M Wills

2013-06-01

Full Text Available A reduction in number and an increase in size of inflorescences is a common aspect of plant domestication. When maize was domesticated from teosinte, the number and arrangement of ears changed dramatically. Teosinte has long lateral branches that bear multiple small ears at their nodes and tassels at their tips. Maize has much shorter lateral branches that are tipped by a single large ear with no additional ears at the branch nodes. To investigate the genetic basis of this difference in prolificacy (the number of ears on a plant, we performed a genome-wide QTL scan. A large effect QTL for prolificacy (prol1.1 was detected on the short arm of chromosome 1 in a location that has previously been shown to influence multiple domestication traits. We fine-mapped prol1.1 to a 2.7 kb "causative region" upstream of the grassy tillers1 (gt1 gene, which encodes a homeodomain leucine zipper transcription factor. Tissue in situ hybridizations reveal that the maize allele of prol1.1 is associated with up-regulation of gt1 expression in the nodal plexus. Given that maize does not initiate secondary ear buds, the expression of gt1 in the nodal plexus in maize may suppress their initiation. Population genetic analyses indicate positive selection on the maize allele of prol1.1, causing a partial sweep that fixed the maize allele throughout most of domesticated maize. This work shows how a subtle cis-regulatory change in tissue specific gene expression altered plant architecture in a way that improved the harvestability of maize.

Finding the joker among the maize endogenous reference genes for genetically modified organism (GMO) detection.

Science.gov (United States)

Paternò, Annalisa; Marchesi, Ugo; Gatto, Francesco; Verginelli, Daniela; Quarchioni, Cinzia; Fusco, Cristiana; Zepparoni, Alessia; Amaddeo, Demetrio; Ciabatti, Ilaria

2009-12-09

The comparison of five real-time polymerase chain reaction (PCR) methods targeted at maize ( Zea mays ) endogenous sequences is reported. PCR targets were the alcohol dehydrogenase (adh) gene for three methods and high-mobility group (hmg) gene for the other two. The five real-time PCR methods have been checked under repeatability conditions at several dilution levels on both pooled DNA template from several genetically modified (GM) maize certified reference materials (CRMs) and single CRM DNA extracts. Slopes and R(2) coefficients of all of the curves obtained from the adopted regression model were compared within the same method and among all of the five methods, and the limit of detection and limit of quantitation were analyzed for each PCR system. Furthermore, method equivalency was evaluated on the basis of the ability to estimate the target haploid genome copy number at each concentration level. Results indicated that, among the five methods tested, one of the hmg-targeted PCR systems can be considered equivalent to the others but shows the best regression parameters and a higher repeteability along the dilution range. Thereby, it is proposed as a valid module to be coupled to different event-specific real-time PCR for maize genetically modified organism (GMO) quantitation. The resulting practicability improvement on the analytical control of GMOs is discussed.

Construction and functional analysis of Trichoderma harzianum mutants that modulate maize resistance to the pathogen Curvularia lunata.

Science.gov (United States)

Fan, Lili; Fu, Kehe; Yu, Chuanjin; Ma, Jia; Li, Yaqian; Chen, Jie

2014-01-01

Agrobacterium tumefaciens-mediated transformation (ATMT) was used to generate an insertional mutant library of the mycelial fungus Trichoderma harzianum. From a total of 450 mutants, six mutants that showed significant influence on maize resistance to C. lunata were analyzed in detail. Maize coated with these mutants was more susceptible to C. lunata compared with those coated with a wild-type (WT) strain. Similar to other fungal ATMT libraries, all six mutants were single copy integrations, which occurred preferentially in noncoding regions (except two mutants) and were frequently accompanied by the loss of border sequences. Two mutants (T66 and T312) that were linked to resistance were characterized further. Maize seeds coated with T66 and T312 were more susceptible to C. lunata than those treated with WT. Moreover, the mutants affected the resistance of maize to C. lunata by enhancing jasmonate-responsive gene expression. T66 and T312 induced maize resistance to C. lunata infection through a jasmonic acid-dependent pathway.

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.

Quality characteristics of bread produced from wheat, rice and maize flours.

Science.gov (United States)

Rai, Sweta; Kaur, Amarjeet; Singh, Baljit; Minhas, K S

2012-12-01

Rice (Oryza sativa) flour and maize (Zea mays) meal substitution in wheat (Triticum aestivum) flour, from 0 to 100% each, for the production of bread was investigated. The proximate analysis, pasting properties, bread making qualities of raw materials and sensory evaluation of the bread samples were determined. The pasting temperature increased with increased percentage of rice flour and maize meal. But the other pasting characters decreased with the higher proportion of rice flour. The baking absorption was observed to increase with higher level of maize meal but it decreased when level of rice flour was increased. Loaf weight (g) decreased with progressive increase in the proportion of maize meal but increased when rice flour incorporation was increased. Loaf volume, loaf height and specific volume decreased for progressively higher level of maize meal and rice flour. The sensory evaluation revealed that 25% replacement of wheat flour was found to be more acceptable than control sample.

Expression and characterization of a recombinant maize CK-2 alpha subunit

DEFF Research Database (Denmark)

Boldyreff, B; Meggio, F; Dobrowolska, G

1993-01-01

to support the immunological data also by biochemical and biophysical experiments the availability of a recombinant CK-2 alpha from maize was a prerequisite. A maize cDNA clone of maize CK-2 alpha was expressed in the bacterial strain BL21 (DE3). The recombinant protein was purified to homogeneity; its......CKIIB, one of the CK-2 like enzymes which have been isolated from maize, has been shown to be a monomeric enzyme that cross-reacts with anti CK-2 alpha specific antibodies suggesting a possible relationship between the two proteins (Dobrowolska et al. (1992) Eur. J. Biochem. 204, 299-303). In order...... molecular mass on one-dimensional SDS PAGE was estimated to be 36.5 kDa. The calculated molecular mass according to the amino acid composition is 39,228 Da (332 amino acids). The recombinant maize CK-2 alpha (rmCK-2 alpha) exhibited mostly the same properties as the recombinant human CK-2 alpha (rhCK-2...

Isolation, structural analysis, and expression characteristics of the maize nuclear factor Y gene families

International Nuclear Information System (INIS)

Zhang, Zhongbao; Li, Xianglong; Zhang, Chun; Zou, Huawen; Wu, Zhongyi

2016-01-01

NUCLEAR FACTOR-Y (NF-Y) has been shown to play an important role in growth, development, and response to environmental stress. A NF-Y complex, which consists of three subunits, NF-YA, NF-YB, and, NF-YC, binds to CCAAT sequences in a promoter to control the expression of target genes. Although NF-Y proteins have been reported in Arabidopsis and rice, a comprehensive and systematic analysis of ZmNF-Y genes has not yet been performed. To examine the functions of ZmNF-Y genes in this family, we isolated and characterized 50 ZmNF-Y (14 ZmNF-YA, 18 ZmNF-YB, and 18 ZmNF-YC) genes in an analysis of the maize genome. The 50 ZmNF-Y genes were distributed on all 10 maize chromosomes, and 12 paralogs were identified. Multiple alignments showed that maize ZmNF-Y family proteins had conserved regions and relatively variable N-terminal or C-terminal domains. The comparative syntenic map illustrated 40 paralogous NF-Y gene pairs among the 10 maize chromosomes. Microarray data showed that the ZmNF-Y genes had tissue-specific expression patterns in various maize developmental stages and in response to biotic and abiotic stresses. The results suggested that ZmNF-YB2, 4, 8, 10, 13, and 16 and ZmNF-YC6, 8, and 15 were induced, while ZmNF-YA1, 3, 4, 6, 7, 10, 12, and 13, ZmNF-YB15, and ZmNF-YC3 and 9 were suppressed by drought stress. ZmNF-YA3, ZmNF-YA8 and ZmNF-YA12 were upregulated after infection by the three pathogens, while ZmNF-YA1 and ZmNF-YB2 were suppressed. These results indicate that the ZmNF-Ys may have significant roles in the response to abiotic and biotic stresses. - Highlights: • We indicated a total of 50 members of ZmNF-Y gene family in maize genome. • We analyzed gene structure, protein architecture of ZmNF-Y genes. • Evolution pattern and phylogenic relationships were analyzed among 50 ZmNF-Y genes. • Expression pattern of ZmNF-Ys were detected in various maize tissues. • Transcript levels of ZmNF-Ys were measured under various abiotic and biotic stresses.

Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

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Jason D Thompson

Full Text Available Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

Winnowing DNA for rare sequences: highly specific sequence and methylation based enrichment.

Science.gov (United States)

Thompson, Jason D; Shibahara, Gosuke; Rajan, Sweta; Pel, Joel; Marziali, Andre

2012-01-01

Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue.

Design of Protein Multi-specificity Using an Independent Sequence Search Reduces the Barrier to Low Energy Sequences.

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Alexander M Sevy

2015-07-01

Full Text Available Computational protein design has found great success in engineering proteins for thermodynamic stability, binding specificity, or enzymatic activity in a 'single state' design (SSD paradigm. Multi-specificity design (MSD, on the other hand, involves considering the stability of multiple protein states simultaneously. We have developed a novel MSD algorithm, which we refer to as REstrained CONvergence in multi-specificity design (RECON. The algorithm allows each state to adopt its own sequence throughout the design process rather than enforcing a single sequence on all states. Convergence to a single sequence is encouraged through an incrementally increasing convergence restraint for corresponding positions. Compared to MSD algorithms that enforce (constrain an identical sequence on all states the energy landscape is simplified, which accelerates the search drastically. As a result, RECON can readily be used in simulations with a flexible protein backbone. We have benchmarked RECON on two design tasks. First, we designed antibodies derived from a common germline gene against their diverse targets to assess recovery of the germline, polyspecific sequence. Second, we design "promiscuous", polyspecific proteins against all binding partners and measure recovery of the native sequence. We show that RECON is able to efficiently recover native-like, biologically relevant sequences in this diverse set of protein complexes.

Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky) in storage condition

OpenAIRE

Ram B Paneru; Resham B Thapa

2017-01-01

The maize weevil (Sitophilus zeamais Motschulsky) is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD) with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C). The fin...

Mutations in the maize zeta-carotene desaturase gene lead to viviparous kernel.

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Yan Chen

Full Text Available Preharvest sprouting reduces the maize quality and causes a significant yield loss in maize production. vp-wl2 is a Mutator (Mu-induced viviparous mutant in maize, causing white or pale yellow kernels, dramatically reduced carotenoid and ABA content, and a high level of zeta-carotene accumulation. Here, we reported the cloning of the vp-wl2 gene using a modified digestion-ligation-amplification method (DLA. The results showed that an insertion of Mu9 in the first intron of the zeta-carotene desaturase (ZDS gene results in the vp-wl2 mutation. Previous studies have suggested that ZDS is likely the structural gene of the viviparous9 (vp9 locus. Therefore, we performed an allelic test using vp-wl2 and three vp9 mutants. The results showed that vp-wl2 is a novel allele of the vp9 locus. In addition, the sequences of ZDS gene were identified in these three vp9 alleles. The vp-wl2 mutant gene was subsequently introgressed into four maize inbred lines, and a viviparous phenotype was observed with yield losses from 7.69% to 13.33%.

Quantification of Pseudomonas fluorescens strains F113, CHA0 and Pf153 in the rhizosphere of maize by strain-specific real-time PCR unaffected by the variability of DNA extraction efficiency.

Science.gov (United States)

Von Felten, Andreas; Défago, Geneviève; Maurhofer, Monika

2010-05-01

Pseudomonas fluorescens strains F113 and CHA0 are well-known plant growth-promoting rhizobacteria (PGPR) often used as model strains in biocontrol experiments. To monitor their persistence in large scale field experiments, culture-independent methods are needed. In this study, a strain-specific real-time PCR quantification tool was developed based on sequence-characterized amplified regions (SCAR) for P. fluorescens strains F113, CHA0 and Pf153. Differences in DNA extraction efficiencies from rhizosphere samples were circumvented using plasmid APA9 as internal standard to normalize C(T) values after real-time amplification. The detection limits of the real-time PCR assays for all three strains were approximately 10 cells for genomic DNA and 10(4)cells/g rhizosphere for maize samples grown in different natural soils. Population sizes of the three strains in the rhizosphere of maize measured by the new real-time PCR approaches were similar to those measured by most probable number (MPN)-PCR. A persistence study of the three strains indicated that the strains persisted differently over a period of 5weeks. In conclusion the newly developed real-time PCR approach is a fast and resource efficient method for monitoring individual biocontrol strains in natural soil, which makes it an apt quantification tool for future large-scale field experiments. Copyright 2010 Elsevier B.V. All rights reserved.

Occurrence of toxigenic fungi in maize and maize-gluten meal from Pakistan

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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%.

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. © 2014 New York Academy of Sciences. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Aflatoxin levels in maize and maize products during the 2004 food ...

African Journals Online (AJOL)

Aflatoxin levels in maize and maize products during the 2004 food poisoning ... district were received at the National Public Health Laboratory Services (NPHLS). On analysis, they were found to be highly contaminated with aflatoxin B1.

Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields.

Science.gov (United States)

Sebők, Flóra; Dobolyi, Csaba; Zágoni, Dóra; Risa, Anita; Krifaton, Csilla; Hartman, Mátyás; Cserháti, Mátyás; Szoboszlay, Sándor; Kriszt, Balázs

2016-12-01

Due to the climate change, aflatoxigenic Aspergillus species and strains have appeared in several European countries, contaminating different agricultural commodities with aflatoxin. Our aim was to screen the presence of aflatoxigenic fungi in maize fields throughout the seven geographic regions of Hungary. Fungi belonging to Aspergillus section Flavi were isolated in the ratio of 26.9% and 42.3% from soil and maize samples in 2013, and these ratios decreased to 16.1% and 34.7% in 2014. Based on morphological characteristics and the sequence analysis of the partial calmodulin gene, all isolates proved to be Aspergillus flavus, except four strains, which were identified as Aspergillus parasiticus. About half of the A. flavus strains and all the A. parasiticus strains were able to synthesize aflatoxins. Aflatoxigenic Aspergillus strains were isolated from all the seven regions of Hungary. A. parasiticus strains were found in the soil of the regions Southern Great Plain and Southern Transdanubia and in a maize sample of the region Western Transdanubia. In spite of the fact that aflatoxins have rarely been detected in feeds and foods in Hungary, aflatoxigenic A. flavus and A. parasiticus strains are present in the maize culture throughout Hungary posing a potential threat to food safety.

Influence of maize flour particle size on gluten-free breadmaking.

Science.gov (United States)

de la Hera, Esther; Talegón, María; Caballero, Pedro; Gómez, Manuel

2013-03-15

Maize, one of the suitable grains for coeliac consumption, is, together with rice, the most cultivated cereal in the world. However, the inclusion of maize flour in gluten-free bread is a minority and studies are scarce. This paper analyses the influence of different maize flour types and their particle sizes on the quality of two types of bread without gluten (80% and 110% water in the formulation) obtained from them. We also analysed the microstructure of the dough and its behaviour during the fermentation. Finer flours had a lower dough development during fermentation in all cases. Among the different types of flour, those whose microstructure revealed compact particles were those which had higher specific bread volume, especially when the particle size was greater. Among the formulations, the dough with more water gave breads with higher specific volume, an effect that was more important in more compact flours. The higher volume breads had lower values of hardness and resilience. The type of corn flour and mainly its particle size influence significantly the dough development of gluten-free bread during fermentation and therefore the final volume and texture of the breads obtained. The flours having coarser particle size are the most suitable for making gluten-free maize bread. © 2012 Society of Chemical Industry.

Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003–2004)

Science.gov (United States)

Ortiz-García, S.; Ezcurra, E.; Schoel, B.; Acevedo, F.; Soberón, J.; Snow, A. A.

2005-01-01

In 2000, transgenes were detected in local maize varieties (landraces) in the mountains of Oaxaca, Mexico [Quist, D. & Chapela, I. H. (2001) Nature 414, 541–543]. This region is part of the Mesoamerican center of origin for maize (Zea mays L.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. The presence of transgenes in landraces was significant because transgenic maize has never been approved for cultivation in Mexico. Here we provide a systematic survey of the frequency of transgenes in currently grown landraces. We sampled maize seeds from 870 plants in 125 fields and 18 localities in the state of Oaxaca during 2003 and 2004. We then screened 153,746 sampled seeds for the presence of two transgene elements from the 35S promoter of the cauliflower mosaic virus and the nopaline synthase gene (nopaline synthase terminator) from Agrobacterium tumefaciens. One or both of these transgene elements are present in all transgenic commercial varieties of maize. No transgenic sequences were detected with highly sensitive PCR-based markers, appropriate positive and negative controls, and duplicate samples for DNA extraction. We conclude that transgenic maize seeds were absent or extremely rare in the sampled fields. This study provides a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico. PMID:16093316

Detection of Genes that Determine Maize Grain Quality Characteristics and Resistance to Stress Factors

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Markovskyi, O.V.

2014-01-01

Full Text Available 200 experimental maize samples (Maize Company were examined for the presence of genes that determine the quality characteristics of grain (wx and fl-2 genes, herbicide (bar (pat, epsps genes and insect (cry-genes resistance. The total DNA was extracted from maize living plant tissue. Primers to detect wx, fl-2, bar (pat, mepsps, CP4 epsps, cry1A(b, cry1F, cry1A.105, mcry3A, cry2Ab2, cry3Bb1, cry34Ab1, cry35Ab1 genes were designed and selected. Multiplex and Touchdown PCR were worked out. PCR amplification of certain sequences was carried out. No transgenes (bar (pat, mepsps, CP4 epsps, cry1A(b, cry1F, cry1A.105, mcry3A, cry2Ab2, cry3Bb1, cry34Ab1, cry35Ab1 were found among 200 analyzed experimental maize samples. At the same time, fl-2 gene was found in 41 samples, wx gene was found in 192 analyzed samples.

BUCKWHEAT AS A GLUTEN-FREE CEREAL IN COMBINATION WITH MAIZE FLOUR

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Stanislav Kráčmar

2012-02-01

Full Text Available Celiac disease is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages. Symptoms include chronic diarrhoea, and fatigue. The only treatment is long life diet with absence of gluten. Many researches concerning gluten-free nutrition have been done but it is still a big challenge. The main aim of this work was to observe changes in gluten-free breads quality made from maize-buckwheat mixtures depending on ratio of maize and buckwheat flour. To obtain samples, bread baking test was applied and these were provided to analyses (dough and pastry yield, baking loss, specific volume and texture analysis. The results showed that rising amount of maize flour in mixtures improved texture characteristics such as chewiness and gumminess, concerning specific volume of breads no significant differences were found and it was proved, that all texture parameters deteriorate with staling time.

Zinc solubilizing Bacillus spp. potential candidates for biofortification in maize.

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Mumtaz, Muhammad Zahid; Ahmad, Maqshoof; Jamil, Moazzam; Hussain, Tanveer

2017-09-01

Bioaugmentation of Zn solubilizing rhizobacteria could be a sustainable intervention to increase bioavailability of Zn in soil which can be helpful in mitigation of yield loss and malnutrition of zinc. In present study, a number of pure rhizobacterial colonies were isolated from maize rhizosphere and screened for their ability to solubilize zinc oxide. These isolates were screened on the basis of zinc and phosphate solubilization, IAA production, protease production, catalase activity and starch hydrolysis. All the selected isolates were also positive for oxidase activity (except ZM22), HCN production (except ZM27) and utilization of citrate. More than 70% of isolates produces ammonia, hydrogen cyanide, siderophores, exopolysaccharides and cellulase. More than half of isolates also showed potential for urease activity and production of lipase. The ZM31 and S10 were the only isolates which showed the chitinase activity. All these isolates were evaluated in a jar trial for their ability to promote growth of maize under axenic conditions. Results revealed that inoculation of selected zinc solubilizing rhizobacterial isolates improved the growth of maize. In comparison, isolates ZM20, ZM31, ZM63 and S10 were best compared to other tested isolates in stimulating the growth attributes of maize like shoot length, root length, plant fresh and dry biomass. These strains were identified as Bacillus sp. (ZM20), Bacillus aryabhattai (ZM31 and S10) and Bacillus subtilis (ZM63) through 16S rRNA sequencing. This study indicated that inoculation of Zn solubilizing strains have potential to promote growth and can be the potential bio-inoculants for biofortification of maize to overcome the problems of malnutrition. Copyright © 2017 Elsevier GmbH. All rights reserved.

Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky in storage condition

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Ram B Paneru

2017-12-01

Full Text Available The maize weevil (Sitophilus zeamais Motschulsky is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C. The findings showed that the maize genotypes had different response to maize weevil damage ranging from susceptible to tolerance. The genotypes Manakamana-3, Lumle White POP Corn and Ganesh-2 showed their tolerance to S. zeamais as evidenced by lower number of weevil emerged/attracted, lower amount of grain debris release and lower proportion of bored grains, while the genotype ZM-627 was the most susceptible to weevil damage in both tests. The other remaining genotypes were intermediate types. This information is useful to improve grain protection in storage and varietal improvement/release program.

Exploiting CRISPR-Cas nucleases to produce sequence-specific antimicrobials.

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Bikard, David; Euler, Chad W; Jiang, Wenyan; Nussenzweig, Philip M; Goldberg, Gregory W; Duportet, Xavier; Fischetti, Vincent A; Marraffini, Luciano A

2014-11-01

Antibiotics target conserved bacterial cellular pathways or growth functions and therefore cannot selectively kill specific members of a complex microbial population. Here, we develop programmable, sequence-specific antimicrobials using the RNA-guided nuclease Cas9 (refs.1,2) delivered by a bacteriophage. We show that Cas9, reprogrammed to target virulence genes, kills virulent, but not avirulent, Staphylococcus aureus. Reprogramming the nuclease to target antibiotic resistance genes destroys staphylococcal plasmids that harbor antibiotic resistance genes and immunizes avirulent staphylococci to prevent the spread of plasmid-borne resistance genes. We also show that CRISPR-Cas9 antimicrobials function in vivo to kill S. aureus in a mouse skin colonization model. This technology creates opportunities to manipulate complex bacterial populations in a sequence-specific manner.

The efficacy of high-throughput sequencing and target enrichment on charred archaeobotanical remains

DEFF Research Database (Denmark)

Nistelberger, H. M.; Smith, O.; Wales, Nathan

2016-01-01

. It has been suggested that high-throughput sequencing (HTS) technologies coupled with DNA enrichment techniques may overcome some of these limitations. Here we report the findings of HTS and target enrichment on four important archaeological crops (barley, grape, maize and rice) performed in three...... lightly-charred maize cob. Even with target enrichment, this sample failed to yield adequate data required to address fundamental questions in archaeology and biology. We further reanalysed part of an existing dataset on charred plant material, and found all purported endogenous DNA sequences were likely...

Survey of Candidate Genes for Maize Resistance to Infection by Aspergillus flavus and/or Aflatoxin Contamination

Science.gov (United States)

Hawkins, Leigh K.; Tang, Juliet D.; Tomashek, John; Alves Oliveira, Dafne; Ogunola, Oluwaseun F.; Smith, J. Spencer; Williams, W. Paul

2018-01-01

Many projects have identified candidate genes for resistance to aflatoxin accumulation or Aspergillus flavus infection and growth in maize using genetic mapping, genomics, transcriptomics and/or proteomics studies. However, only a small percentage of these candidates have been validated in field conditions, and their relative contribution to resistance, if any, is unknown. This study presents a consolidated list of candidate genes identified in past studies or in-house studies, with descriptive data including genetic location, gene annotation, known protein identifiers, and associated pathway information, if known. A candidate gene pipeline to test the phenotypic effect of any maize DNA sequence on aflatoxin accumulation resistance was used in this study to determine any measurable effect on polymorphisms within or linked to the candidate gene sequences, and the results are published here. PMID:29385107

Survey of Candidate Genes for Maize Resistance to Infection by Aspergillus flavus and/or Aflatoxin Contamination

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Leigh K. Hawkins

2018-01-01

Full Text Available Many projects have identified candidate genes for resistance to aflatoxin accumulation or Aspergillus flavus infection and growth in maize using genetic mapping, genomics, transcriptomics and/or proteomics studies. However, only a small percentage of these candidates have been validated in field conditions, and their relative contribution to resistance, if any, is unknown. This study presents a consolidated list of candidate genes identified in past studies or in-house studies, with descriptive data including genetic location, gene annotation, known protein identifiers, and associated pathway information, if known. A candidate gene pipeline to test the phenotypic effect of any maize DNA sequence on aflatoxin accumulation resistance was used in this study to determine any measurable effect on polymorphisms within or linked to the candidate gene sequences, and the results are published here.

Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain.

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García-Carneros, A B; Girón, I; Molinero-Ruiz, L

2012-01-01

Late wilt of maize, caused by the vascular and soilborne pathogen Cephalosporium maydis, was identified in the Iberian Peninsula in 2008. During the last years the incidence and economical impact of the disease has importantly increased both in Portugal and Spain. Varieties of maize displaying tolerance to the pathogen are available, but the effectiveness can be dependent on the virulence of the fungus (i.e. ability to cause disease on a specific genotype). On the other hand, strains of crop pathogens from different geographic origins can differ with regard to the degree of disease caused on a specific genotype (i.e. aggressiveness). Our working hypothesis was that isolates of C. maydis from different maize growing areas may differ in aggressiveness towards maize plants. Seven fungal strains were isolated in 2009 from diseased plants collected in the most important maize growing regions of Spain and used to inoculate two susceptible maize varieties grown in shadehouse from March to July 2010. The experimental unit consisted of two 4-day-old seedlings planted in an 8-liter pot filled with sand/silt previously infested with 200 g of wheat grains colonized by the fungi. Non colonized wheat grains were used for the control treatments. Six replications (pots) were established for each variety/isolate combination according to a complete randomized 2 x 8 factorial design. The percentage of necrotic and dry aboveground tissues was recorded 14 weeks after inoculation and thereafter weekly until physiological senescence of the control plants. At the end of the experiment, weights of roots and aboveground parts of the plants were recorded. Initial occurrence of symptoms in the plants was significantly dependent on the isolate of C. maydis and on the maize variety. However, final severity of aboveground symptoms (leaf necroses and drying up) was only dependent on the fungal isolate. All the isolates significantly reduced the root weight of both varieties of maize. The highest

The HAP Complex Governs Fumonisin Biosynthesis and Maize Kernel Pathogenesis in Fusarium verticillioides.

Science.gov (United States)

Ridenour, John B; Smith, Jonathon E; Bluhm, Burton H

2016-09-01

Contamination of maize ( Zea mays ) with fumonisins produced by the fungus Fusarium verticillioides is a global concern for food safety. Fumonisins are a group of polyketide-derived secondary metabolites linked to esophageal cancer and neural tube birth defects in humans and numerous toxicoses in livestock. Despite the importance of fumonisins in global maize production, the regulation of fumonisin biosynthesis during kernel pathogenesis is poorly understood. The HAP complex is a conserved, heterotrimeric transcriptional regulator that binds the consensus sequence CCAAT to modulate gene expression. Recently, functional characterization of the Hap3 subunit linked the HAP complex to the regulation of secondary metabolism and stalk rot pathogenesis in F. verticillioides . Here, we determine the involvement of HAP3 in fumonisin biosynthesis and kernel pathogenesis. Deletion of HAP3 suppressed fumonisin biosynthesis on both nonviable and live maize kernels and impaired pathogenesis in living kernels. Transcriptional profiling via RNA sequencing indicated that the HAP complex regulates at least 1,223 genes in F. verticillioides , representing nearly 10% of all predicted genes. Disruption of the HAP complex caused the misregulation of biosynthetic gene clusters underlying the production of secondary metabolites, including fusarins. Taken together, these results reveal that the HAP complex is a central regulator of fumonisin biosynthesis and kernel pathogenesis and works as both a positive and negative regulator of secondary metabolism in F. verticillioides .

Consumer preferences for maize products in urban Kenya.

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De Groote, Hugo; Kimenju, Simon Chege

2012-06-01

New maize varieties have been biofortified with provitamin A, mainly a-carotene, which renders the grain yellow or orange. Unfortunately, many African consumers prefer white maize. The maize consumption patterns in Africa are, however, not known. To determine which maize products African consumers prefer to purchase and which maize preparations they prefer to eat. A survey of 600 consumers was conducted in Nairobi, Kenya, at three types of maize outlets: posho mills (small hammer mills), kiosks, and supermarkets. Clients of posho mills had lower incomes and less education than those of kiosks and supermarkets. The preferred maize product of the posho-mill clients was artisanal maize meal; the preferred product of the others was industrial maize meal. Maize is the preferred staple for lunch and dinner, eaten as a stiff porridge (ugali), followed by boiled maize and beans (githeri), regardless of socioeconomic background. For breakfast, only half the consumers prefer maize, mostly as a soft porridge (uji). This proportion is higher in low-income groups. Consumers show a strong preference for white maize over yellow, mostly for its organoleptic characteristics, and show less interest in biofortified maize. Maize is the major food staple in Nairobi, mostly eaten in a few distinct preparations. For biofortified yellow maize to be accepted, a strong public awareness campaign to inform consumers is needed, based on a sensory evaluation and the mass media, in particular on radio in the local language.

Co-expression network analysis of duplicate genes in maize (Zea mays L.) reveals no subgenome bias.

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Li, Lin; Briskine, Roman; Schaefer, Robert; Schnable, Patrick S; Myers, Chad L; Flagel, Lex E; Springer, Nathan M; Muehlbauer, Gary J

2016-11-04

Gene duplication is prevalent in many species and can result in coding and regulatory divergence. Gene duplications can be classified as whole genome duplication (WGD), tandem and inserted (non-syntenic). In maize, WGD resulted in the subgenomes maize1 and maize2, of which maize1 is considered the dominant subgenome. However, the landscape of co-expression network divergence of duplicate genes in maize is still largely uncharacterized. To address the consequence of gene duplication on co-expression network divergence, we developed a gene co-expression network from RNA-seq data derived from 64 different tissues/stages of the maize reference inbred-B73. WGD, tandem and inserted gene duplications exhibited distinct regulatory divergence. Inserted duplicate genes were more likely to be singletons in the co-expression networks, while WGD duplicate genes were likely to be co-expressed with other genes. Tandem duplicate genes were enriched in the co-expression pattern where co-expressed genes were nearly identical for the duplicates in the network. Older gene duplications exhibit more extensive co-expression variation than younger duplications. Overall, non-syntenic genes primarily from inserted duplications show more co-expression divergence. Also, such enlarged co-expression divergence is significantly related to duplication age. Moreover, subgenome dominance was not observed in the co-expression networks - maize1 and maize2 exhibit similar levels of intra subgenome correlations. Intriguingly, the level of inter subgenome co-expression was similar to the level of intra subgenome correlations, and genes from specific subgenomes were not likely to be the enriched in co-expression network modules and the hub genes were not predominantly from any specific subgenomes in maize. Our work provides a comprehensive analysis of maize co-expression network divergence for three different types of gene duplications and identifies potential relationships between duplication types

Identification of small secreted peptides (SSPs) in maize and expression analysis of partial SSP genes in reproductive tissues.

Science.gov (United States)

Li, Ye Long; Dai, Xin Ren; Yue, Xun; Gao, Xin-Qi; Zhang, Xian Sheng

2014-10-01

Maize 1,491 small secreted peptides were identified, which were classified according to the character of peptide sequences. Partial SSP gene expressions in reproductive tissues were determined by qRT-PCR. Small secreted peptides (SSPs) are important cell-cell communication messengers in plants. Most information on plant SSPs come from Arabidopsis thaliana and Oryza sativa, while little is known about the SSPs of other grass species such as maize (Zea mays). In this study, we identified 1,491 SSP genes from maize genomic sequences. These putative SSP genes were distributed throughout the ten maize chromosomes. Among them, 611 SSPs were classified into 198 superfamilies according to their conserved domains, and 725 SSPs with four or more cysteines at their C-termini shared similar cysteine arrangements with their counterparts in other plant species. Moreover, the SSPs requiring post-translational modification, as well as defensin-like (DEFL) proteins, were identified. Further, the expression levels of 110 SSP genes were analyzed in reproductive tissues, including male flower, pollen, silk, and ovary. Most of the genes encoding basal-layer antifungal peptide-like, small coat proteins-like, thioredoxin-like proteins, γ-thionins-like, and DEFL proteins showed high expression levels in the ovary and male flower compared with their levels in silk and mature pollen. The rapid alkalinization factor-like genes were highly expressed only in the mature ovary and mature pollen, and pollen Ole e 1-like genes showed low expression in silk. The results of this study provide basic information for further analysis of SSP functions in the reproductive process of maize.

Omethoate treatment mitigates high salt stress inhibited maize seed germination.

Science.gov (United States)

Yang, Kejun; Zhang, Yifei; Zhu, Lianhua; Li, Zuotong; Deng, Benliang

2018-01-01

Omethoate (OM) is a highly toxic organophophate insecticide, which is resistant to biodegradation in the environment and is widely used for pest control in agriculture. The effect of OM on maize seed germination was evaluated under salt stress. Salt (800mM) greatly reduced germination of maize seed and this could be reversed by OM. Additionally, H 2 O 2 treatment further improved the effect of OM on seed germination. Higher H 2 O 2 content was measured in OM treated seed compared to those with salt stress alone. Dimethylthiourea (DTMU), a specific scavenger of reactive oxygen species (ROS), inhibited the effect of OM on seed germination, as did IMZ (imidazole), an inhibitor of NADPH oxidase. Abscisic acid (ABA) inhibited the effect of OM on seed germination, whereas fluridone, a specific inhibitor of ABA biosynthesis, enhanced the effect of OM. Taken together, these findings suggest a role of ROS and ABA in the promotion of maize seed germination by OM under salt stress. Copyright © 2017 Elsevier Inc. All rights reserved.

Spatial and temporal activity of the foxtail millet (Setaria italica) seed-specific promoter pF128.

Science.gov (United States)

Pan, Yanlin; Ma, Xin; Liang, Hanwen; Zhao, Qian; Zhu, Dengyun; Yu, Jingjuan

2015-01-01

pF128 drives GUS specifically expressed in transgenic seeds of foxtail millet and Zea mays with higher activity than the constitutive CaMV35S promoter and the maize seed-specific 19Z promoter. Foxtail millet (Setaria italica), a member of the Poaceae family, is an important food and fodder crop in arid regions. Foxtail millet is an excellent C4 crop model owing to its small genome (~490 Mb), self-pollination and availability of a complete genome sequence. F128 was isolated from a cDNA library of foxtail millet immature seeds. Real-time PCR analysis revealed that F128 mRNA was specifically expressed in immature and mature seeds. The highest F128 mRNA level was observed 5 days after pollination and gradually decreased as the seed matured. Sequence analysis suggested that the protein encoded by F128 is likely a protease inhibitor/seed storage protein/lipid-transfer protein. The 1,053 bp 5' flanking sequence of F128 (pF128) was isolated and fused to the GUS reporter gene. The corresponding vector was then transformed into Arabidopsis thaliana, foxtail millet and Zea mays. GUS analysis revealed that pF128 drove GUS expression efficiently and specifically in the seeds of transgenic Arabidopsis, foxtail millet and Zea mays. GUS activity was also detected in Arabidopsis cotyledons. Activity of pF128 was higher than that observed for the constitutive CaMV35S promoter and the maize seed-specific 19 Zein (19Z) promoter. These results indicate that pF128 is a seed-specific promoter. Its application is expected to be of considerable value in plant genetic engineering.

Correlation of Aquaporins and Transmembrane Solute Transporters Revealed by Genome-Wide Analysis in Developing Maize Leaf

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Xun Yue

2012-01-01

Full Text Available Aquaporins are multifunctional membrane channels that facilitate the transmembrane transport of water and solutes. When transmembrane mineral nutrient transporters exhibit the same expression patterns as aquaporins under diverse temporal and physiological conditions, there is a greater probability that they interact. In this study, genome-wide temporal profiling of transcripts analysis and coexpression network-based approaches are used to examine the significant specificity correlation of aquaporins and transmembrane solute transporters in developing maize leaf. The results indicate that specific maize aquaporins are related to specific transmembrane solute transporters. The analysis demonstrates a systems-level correlation between aquaporins, nutrient transporters, and the homeostasis of mineral nutrients in developing maize leaf. Our results provide a resource for further studies into the physiological function of these aquaporins.

The B73 maize genome: complexity, diversity, and dynamics.

Science.gov (United States)

Schnable, Patrick S; Ware, Doreen; Fulton, Robert S; Stein, Joshua C; Wei, Fusheng; Pasternak, Shiran; Liang, Chengzhi; Zhang, Jianwei; Fulton, Lucinda; Graves, Tina A; Minx, Patrick; Reily, Amy Denise; Courtney, Laura; Kruchowski, Scott S; Tomlinson, Chad; Strong, Cindy; Delehaunty, Kim; Fronick, Catrina; Courtney, Bill; Rock, Susan M; Belter, Eddie; Du, Feiyu; Kim, Kyung; Abbott, Rachel M; Cotton, Marc; Levy, Andy; Marchetto, Pamela; Ochoa, Kerri; Jackson, Stephanie M; Gillam, Barbara; Chen, Weizu; Yan, Le; Higginbotham, Jamey; Cardenas, Marco; Waligorski, Jason; Applebaum, Elizabeth; Phelps, Lindsey; Falcone, Jason; Kanchi, Krishna; Thane, Thynn; Scimone, Adam; Thane, Nay; Henke, Jessica; Wang, Tom; Ruppert, Jessica; Shah, Neha; Rotter, Kelsi; Hodges, Jennifer; Ingenthron, Elizabeth; Cordes, Matt; Kohlberg, Sara; Sgro, Jennifer; Delgado, Brandon; Mead, Kelly; Chinwalla, Asif; Leonard, Shawn; Crouse, Kevin; Collura, Kristi; Kudrna, Dave; Currie, Jennifer; He, Ruifeng; Angelova, Angelina; Rajasekar, Shanmugam; Mueller, Teri; Lomeli, Rene; Scara, Gabriel; Ko, Ara; Delaney, Krista; Wissotski, Marina; Lopez, Georgina; Campos, David; Braidotti, Michele; Ashley, Elizabeth; Golser, Wolfgang; Kim, HyeRan; Lee, Seunghee; Lin, Jinke; Dujmic, Zeljko; Kim, Woojin; Talag, Jayson; Zuccolo, Andrea; Fan, Chuanzhu; Sebastian, Aswathy; Kramer, Melissa; Spiegel, Lori; Nascimento, Lidia; Zutavern, Theresa; Miller, Beth; Ambroise, Claude; Muller, Stephanie; Spooner, Will; Narechania, Apurva; Ren, Liya; Wei, Sharon; Kumari, Sunita; Faga, Ben; Levy, Michael J; McMahan, Linda; Van Buren, Peter; Vaughn, Matthew W; Ying, Kai; Yeh, Cheng-Ting; Emrich, Scott J; Jia, Yi; Kalyanaraman, Ananth; Hsia, An-Ping; Barbazuk, W Brad; Baucom, Regina S; Brutnell, Thomas P; Carpita, Nicholas C; Chaparro, Cristian; Chia, Jer-Ming; Deragon, Jean-Marc; Estill, James C; Fu, Yan; Jeddeloh, Jeffrey A; Han, Yujun; Lee, Hyeran; Li, Pinghua; Lisch, Damon R; Liu, Sanzhen; Liu, Zhijie; Nagel, Dawn Holligan; McCann, Maureen C; SanMiguel, Phillip; Myers, Alan M; Nettleton, Dan; Nguyen, John; Penning, Bryan W; Ponnala, Lalit; Schneider, Kevin L; Schwartz, David C; Sharma, Anupma; Soderlund, Carol; Springer, Nathan M; Sun, Qi; Wang, Hao; Waterman, Michael; Westerman, Richard; Wolfgruber, Thomas K; Yang, Lixing; Yu, Yeisoo; Zhang, Lifang; Zhou, Shiguo; Zhu, Qihui; Bennetzen, Jeffrey L; Dawe, R Kelly; Jiang, Jiming; Jiang, Ning; Presting, Gernot G; Wessler, Susan R; Aluru, Srinivas; Martienssen, Robert A; Clifton, Sandra W; McCombie, W Richard; Wing, Rod A; Wilson, Richard K

2009-11-20

We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well as how uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. These analyses inform and set the stage for further investigations to improve our understanding of the domestication and agricultural improvements of maize.

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

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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.

Predicting weed problems in maize cropping by species distribution modelling

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Bürger, Jana

2014-02-01

Full Text Available Increasing maize cultivation and changed cropping practices promote the selection of typical maize weeds that may also profit strongly from climate change. Predicting potential weed problems is of high interest for plant production. Within the project KLIFF, experiments were combined with species distribution modelling for this task in the region of Lower Saxony, Germany. For our study, we modelled ecological and damage niches of nine weed species that are significant and wide spread in maize cropping in a number of European countries. Species distribution models describe the ecological niche of a species, these are the environmental conditions under which a species can maintain a vital population. It is also possible to estimate a damage niche, i.e. the conditions under which a species causes damage in agricultural crops. For this, we combined occurrence data of European national data bases with high resolution climate, soil and land use data. Models were also projected to simulated climate conditions for the time horizon 2070 - 2100 in order to estimate climate change effects. Modelling results indicate favourable conditions for typical maize weed occurrence virtually all over the study region, but only a few species are important in maize cropping. This is in good accordance with the findings of an earlier maize weed monitoring. Reaction to changing climate conditions is species-specific, for some species neutral (E. crus-galli, other species may gain (Polygonum persicaria or loose (Viola arvensis large areas of suitable habitats. All species with damage potential under present conditions will remain important in maize cropping, some more species will gain regional importance (Calystegia sepium, Setara viridis.

Transcription and somatic transposition of the maize En/Spm transposon system in rice

NARCIS (Netherlands)

Greco, R.; Ouwerkerk, P.B.F.; Taal, A.J.C.; Sallaud, C.; Guiderdoni, E.; Meijer, A.H.; Hoge, J.H.C.; Pereira, A.B.

2004-01-01

Transposition of the maize En/Spm system in rice was investigated using a two-component construct consisting of an immobilised transposase source driven by the CaMV 35S-promoter, and a modified I/dSpm transposon. Mobilization of I/dSpm in somatic sectors was demonstrated by sequencing of excision

MaizeGDB: The Maize Model Organism Database for Basic, Translational, and Applied Research

OpenAIRE

Lawrence, Carolyn J.; Harper, Lisa C.; Schaeffer, Mary L.; Sen, Taner Z.; Seigfried, Trent E.; Campbell, Darwin A.

2008-01-01

In 2001 maize became the number one production crop in the world with the Food and Agriculture Organization of the United Nations reporting over 614 million tonnes produced. Its success is due to the high productivity per acre in tandem with a wide variety of commercial uses. Not only is maize an excellent source of food, feed, and fuel, but also its by-products are used in the production of various commercial products. Maize's unparalleled success in agriculture stems from basic research, th...

Genetic resources in maize breeding

Directory of Open Access Journals (Sweden)

Anđelković Violeta

2017-01-01

Full Text Available Maize, wheat and rice are the most important cereals grown in the world. It is predicted that by 2025 maize is likely to become the crop with the greatest production globally. Conservation of maize germplasm provides the main resources for increased food and feed production. Conservation in gene banks (ex-situ is dominant strategy for maize conservation. More than 130 000 maize accessions, e.g. about 40% of total number, are stored in ten largest gene banks worldwide and Maize Research Institute Zemun Polje (MRIZP gene bank, with about 6000 accessions, is among them. Organized collecting missions started in 1961. in the former Yugoslavian territory, and up today, more than 2000 local maize landraces were stored. Pre-breeding activities that refer to identification of desirable traits from unadapted germplasm within genebank, result in materials expected to be included in breeding programs. Successful examples are LAMP, GEM and GENRES projects. At the end of XX century, at MRIZP genebank two pre-breeding activities were undertaken: eco-core and elite-core collections were created and landraces fulfilled particular criteria were chosen. In the last decade, MRIZP genebank collection was used for identification of sources for drought tolerance and improved grain quality. According to agronomic traits and general combining ability, two mini-core collections were created and included in commercial breeding programs.

Exceptional diversity, non-random distribution, and rapid evolution of retroelements in the B73 maize genome.

Directory of Open Access Journals (Sweden)

Regina S Baucom

2009-11-01

Full Text Available Recent comprehensive sequence analysis of the maize genome now permits detailed discovery and description of all transposable elements (TEs in this complex nuclear environment. Reiteratively optimized structural and homology criteria were used in the computer-assisted search for retroelements, TEs that transpose by reverse transcription of an RNA intermediate, with the final results verified by manual inspection. Retroelements were found to occupy the majority (>75% of the nuclear genome in maize inbred B73. Unprecedented genetic diversity was discovered in the long terminal repeat (LTR retrotransposon class of retroelements, with >400 families (>350 newly discovered contributing >31,000 intact elements. The two other classes of retroelements, SINEs (four families and LINEs (at least 30 families, were observed to contribute 1,991 and approximately 35,000 copies, respectively, or a combined approximately 1% of the B73 nuclear genome. With regard to fully intact elements, median copy numbers for all retroelement families in maize was 2 because >250 LTR retrotransposon families contained only one or two intact members that could be detected in the B73 draft sequence. The majority, perhaps all, of the investigated retroelement families exhibited non-random dispersal across the maize genome, with LINEs, SINEs, and many low-copy-number LTR retrotransposons exhibiting a bias for accumulation in gene-rich regions. In contrast, most (but not all medium- and high-copy-number LTR retrotransposons were found to preferentially accumulate in gene-poor regions like pericentromeric heterochromatin, while a few high-copy-number families exhibited the opposite bias. Regions of the genome with the highest LTR retrotransposon density contained the lowest LTR retrotransposon diversity. These results indicate that the maize genome provides a great number of different niches for the survival and procreation of a great variety of retroelements that have evolved to

Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

Science.gov (United States)

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

Putting the Function in Maize Genomics

Directory of Open Access Journals (Sweden)

Stephen P. Moose

2009-07-01

Full Text Available The 51st Maize Genetics Conference was held March 12–15, 2009 at Pheasant Run Resort in St. Charles, Illinois. Nearly 500 attendees participated in a scientific program (available at covering a wide range of topics which integrate the rich biology of maize with recent discoveries in our understanding of the highly dynamic maize genome. Among the many research themes highlighted at the conference, the historical emphasis on studying the tremendous phenotypic diversity of maize now serves as the foundation for maize as a leading experimental system to characterize the mechanisms that generate variation in complex plant genomes and associate evolutionary change with phenotypes of interest.

Carbon turnover in two soils with contrasting mineralogy under long-term maize and pasture

International Nuclear Information System (INIS)

Parfitt, R.L.; Parshotam, A.; Salt, G.J.

2002-01-01

Total organic carbon (C) and natural 13 C abundance were measured in adjacent allophanic soils (Andisols) and non-allophanic soils (Inceptisols) under maize (Zea mays L.) and ryegrass pasture (Lolium perenne L.) to assess the C turnover rate in soils of contrasting mineralogy and specific surface area. The allophanic soil contained more total C than the non-allophanic soil (139v.101t C/ha in the upper 0-35 cm) but neither soil showed a significant difference in C content between pasture and maize, provided maize residue was retained and incorporated. The gross annual inputs under maize and pasture were both estimated to be about 9 t C/ha, consistent with the similar soil total C contents. Since the soil total C content did not appear to change with time, the gross C mineralisation was about 9 t C/ha each year. The proportion of old pasture C remaining in the soil after maize cropping for 25 years was about 78% in the allophanic soils and about 69% in the non-allophanic soils, reflecting the influence of both Al and allophane, with its high specific surface area, on the retention of old C. The maize C retained in 25 years was similar in both the allophanic soil and the non-allophanic soil (29 t/ha). Therefore, the higher total C content of the allophanic soil would appear to arise from stabilisation of old pasture and forest C by Al and allophane. Copyright (2002) CSIRO Publishing

Species of Cercospora associated with grey leaf spot of maize.

Science.gov (United States)

Crous, Pedro W; Groenewald, Johannes Z; Groenewald, Marizeth; Caldwell, Pat; Braun, Uwe; Harrington, Thomas C

2006-01-01

Grey leaf spot is a serious yield-reducing disease of maize (Zea mays) in many parts of the world where this crop is cultivated. The causal organism associated with the disease is Cercospora zeae-maydis. Two potential sibling species have been recognized as Groups I and II. The DNA sequences for the internal transcribed spacers (ITS1 & ITS2), the 5.8S rRNA gene, elongation factor 1-alpha, histone H3, actin and calmodulin gene regions suggest that Groups I and II are two distinct species. Furthermore, Cercospora zeae-maydis (Group I) can be distinguished from C. zeina sp. nov. (Group II) by its faster growth rate on artificial media, the ability to produce cercosporin, longer conidiophores, and broadly fusiform conidia. A PCR-based test that distinguishes the two species was developed using species-specific primers designed from the histone H3 gene.

Subchronic feeding study of DAS-59122-7 maize grain in Sprague-Dawley rats.

Science.gov (United States)

Malley, Linda A; Everds, Nancy E; Reynolds, Julia; Mann, Peter C; Lamb, Ian; Rood, Tracy; Schmidt, Jean; Layton, Raymond J; Prochaska, Lee M; Hinds, Mark; Locke, Mary; Chui, Chok-Fun; Claussen, Fred; Mattsson, Joel L; Delaney, Bryan

2007-07-01

59122 is a transgenic maize line containing event DAS-59122-7 that expresses the corn rootworm (CRW) specific pesticidal Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis (Bt) Berliner strain PS149B1 and the phosphinothricin-N-acetyltransferase (PAT) protein from Streptomyces viridochromogenes for tolerance to the herbicidal ingredient glufosinate-ammonium. For the current study, 59122 maize grain, non-transgenic near-isogenic maize grain (091), and a commercially available non-transgenic reference maize grain (33R77) were grown under conditions simulating commercial farming practices. Adult Sprague-Dawley rats (12/sex/group) were fed diets formulated with 35% maize grain from either 59122, 091, or 33R77, or one of two separate lots of commercially available rodent chow prepared with commercially available corn (35%) in accordance with the standards of Purina Mills Labdiet 5002 for approximately 90 days. All diets possessed similar nutritional and contaminant profiles. The transgenic proteins were detected only in diets prepared with 59122 maize grain and were stable over the course of the study. Compared to control groups, no adverse diet-related differences were observed in rats fed diets formulated with 59122 maize grain with respect to body weight/gain, food consumption/efficiency, clinical signs of toxicity, mortality, ophthalmology, neurobehavioral (FOB and motor activity) assessments, clinical pathology (hematology, clinical chemistry, coagulation, and urinalysis), and pathology (organ weights and gross and microscopic pathology). Results from this study indicate that 59122 maize grain is nutritionally equivalent to and as safe as conventional maize grain.

Transcriptional analyses of natural leaf senescence in maize.

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Wei Yang Zhang

Full Text Available Leaf senescence is an important biological process that contributes to grain yield in crops. To study the molecular mechanisms underlying natural leaf senescence, we harvested three different developmental ear leaves of maize, mature leaves (ML, early senescent leaves (ESL, and later senescent leaves (LSL, and analyzed transcriptional changes using RNA-sequencing. Three sets of data, ESL vs. ML, LSL vs. ML, and LSL vs. ESL, were compared, respectively. In total, 4,552 genes were identified as differentially expressed. Functional classification placed these genes into 18 categories including protein metabolism, transporters, and signal transduction. At the early stage of leaf senescence, genes involved in aromatic amino acids (AAAs biosynthetic process and transport, cellular polysaccharide biosynthetic process, and the cell wall macromolecule catabolic process, were up-regulated. Whereas, genes involved in amino acid metabolism, transport, apoptosis, and response to stimulus were up-regulated at the late stage of leaf senescence. Further analyses reveals that the transport-related genes at the early stage of leaf senescence potentially take part in enzyme and amino acid transport and the genes upregulated at the late stage are involved in sugar transport, indicating nutrient recycling mainly takes place at the late stage of leaf senescence. Comparison between the data of natural leaf senescence in this study and previously reported data for Arabidopsis implies that the mechanisms of leaf senescence in maize are basically similar to those in Arabidopsis. A comparison of natural and induced leaf senescence in maize was performed. Athough many basic biological processes involved in senescence occur in both types of leaf senescence, 78.07% of differentially expressed genes in natural leaf senescence were not identifiable in induced leaf senescence, suggesting that differences in gene regulatory network may exist between these two leaf senescence

Phylloplane bacteria of Jatropha curcas: diversity, metabolic characteristics, and growth-promoting attributes towards vigor of maize seedling.

Science.gov (United States)

Dubey, Garima; Kollah, Bharati; Ahirwar, Usha; Mandal, Asit; Thakur, Jyoti Kumar; Patra, Ashok Kumar; Mohanty, Santosh Ranjan

2017-10-01

The complex role of phylloplane microorganisms is less understood than that of rhizospheric microorganisms in lieu of their pivotal role in plant's sustainability. This experiment aims to study the diversity of the culturable phylloplane bacteria of Jatropha curcas and evaluate their growth-promoting activities towards maize seedling vigor. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequences of the 16S rRNA gene were very similar to those of species belonging to the classes Bacillales (50%), Gammaproteobacteria (21.8%), Betaproteobacteria (15.6%), and Alphaproteobacteria (12.5%). The phylloplane bacteria preferred to utilize alcohol rather than monosaccharides and polysaccharides as a carbon source. Isolates exhibited ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, phosphatase, potassium solubilization, and indole acetic acid (IAA) production activities. The phosphate-solubilizing capacity (mg of PO 4 solubilized by 10 8 cells) varied from 0.04 to 0.21. The IAA production potential (μg IAA produced by 10 8 cells in 48 h) of the isolates varied from 0.41 to 9.29. Inoculation of the isolates to maize seed significantly increased shoot and root lengths of maize seedlings. A linear regression model of the plant-growth-promoting activities significantly correlated (p < 0.01) with the growth parameters. Similarly, a correspondence analysis categorized ACC deaminase and IAA production as the major factors contributing 41% and 13.8% variation, respectively, to the growth of maize seedlings.

Identification of resistance to Maize rayado fino virus in maize inbred lines

Science.gov (United States)

Maize rayado fino virus (MRFV) is one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in populations, but few inbred lines have been identifie...

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.

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

Whole-crop maize silage as forage in diets of finishing cattle can promote high intakes and thus, enhances animal performance. In the present study we evaluated the effect of whole-crop maize maturity at harvest and the proportion of maize-silage in diets of finishing bulls, on feed intake...... 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...... distillers’ grain plus soluble; cold-pressed rapeseed cake) in a 40% proportion on DM basis. All animals were slaughtered at a target body weight of 630 kg. Bulls fed on diets containing maize silage as sole forage achieved higher live-weight gain (P

Aggressiveness of Cephalosporium maydis causing late wilt of maize in Spain

OpenAIRE

García-Carneros, Ana B.; Girón, I.; Molinero-Ruiz, Leire

2012-01-01

Late wilt of maize, caused by the vascular and soilborne pathogen Cephalosporium maydis, was identified in the Iberian Peninsula in 2008. During the last years the incidence and economical impact of the disease has importantly increased both in Portugal and Spain. Varieties of maize displaying tolerance to the pathogen are available, but the effectiveness can be dependent on the virulence of the fungus (i.e. ability to cause disease on a specific genotype). On the other hand, strains of crop ...

Evaluation of maize inbred lines for resistance to pre-harvest aflatoxin and fumonisin contamination in the field

Science.gov (United States)

Two important mycotoxins, aflatoxin and fumonisin, are among the most potent naturally occurring carcinogens, contaminating maize (Zea mays L.) and affecting the crop yield and quality. Resistance of maize to pre-harvest mycotoxin contamination, specifically aflatoxin produced by Aspergillus flavus ...

Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identity novel genes expressed during vegetative infectious, and repoductive growth

NARCIS (Netherlands)

Bluhm, B.H.; Lindquist, E.; Kema, G.H.J.; Goodwin, S.B.; Dunkle, L.D.

2008-01-01

The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The

Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation

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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.

Overexpression of a modiifed AM79 aroA gene in transgenic maize confers high tolerance to glyphosate

Institute of Scientific and Technical Information of China (English)

REN Zhen-jing; CAO Gao-yi; ZHANG Yu-wen; LIU Yan; LIU Yun-jun

2015-01-01

It has previously been shown that a bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) encoding gene AM79 aroA can be a candidate gene to develop glyphosate-tolerant transgenic crops (Cao et al. 2012). In this study, AM79 aroA was redesigned using the plant biased codons and eliminating the motifs which would lead to the instability of mRNA, to create a synthetic gene that would be expressed highly in plant cel s. The redesigned and artiifcial y synthesized gene, named as mAM79, was cloned into plant expression vector pM3301UbiSpAM79, where mAM79 is fused with signal peptide sequence of pea rib-1,5-bisphospate carboxylase (rbcS) smal subunit and control ed by ubiquitin promoter. The plasmid was transformed into maize (Zea mays) immature embryos using Agrobacterium-mediated transformation method. Total 74 regenerated plants were obtained and PCR analysis showed that these transgenic plants had the integration of mAM79. Southern blot analysis was performed on the genomic DNA from four transgenic lines, and the result showed that one or two copies of mAM79 were integrated into maize genome. RT-PCR analysis result indicated that mAM79 was highly transcribed in transgenic maize plants. When sprayed with glyphosate, transgenic maize line AM85 and AM72 could tolerate 4-fold of commercial usage of glyphosate;however, al the non-transgenic maize plants were kil ed by glyphosate. The results in this study conifrmed that mAM79 could be used to develop glyphosate-tolerant maize, and the obtained transgenic maize lines could be used for the breeding of glyphosate-tolerant maize.

Some aspects of cultivation and utilization of waxy maize (Zea mays L. ssp. ceratina

Directory of Open Access Journals (Sweden)

Agnieszka Klimek-Kopyra

2012-10-01

Full Text Available This paper is a review of available literature on Zea mays L.ssp.ceratina. It contains information on the origin, cul- tivation and utilization of waxy maize in the world and can be a contribution to the development of new research on maize cultivation and starch processing technology. Maize, as an old and economically important cereal, played an enormous role in the ancient civilisations of the New World. Among the maize subspecies compared, Z. mays ssp. indurata and Z. mays ssp. indentata are now the most important in Poland. The subspecies Z. mays ssp. saccharata has a marginal role, while Z. mays ssp. ceratina has not been hitherto cultivated. Decisions to introduce the subspecies Z. mays ssp. ceratina into cultivation are based on different grounds, taking into account both agro-climatic conditions and industrial uses of grain processing products. The growing demand for maize grain, stimulated by the increased demand for maize starch and oil in the global market as raw materials that are important in food production, is an impulse for the development of agrobiological research. The development of the starch industry, associated with the demand for industrial starch, will probably contribute to increased interest in this subspecies in Central Europe, also including Poland. Waxy maize grain can be a major ingredient of high-energy feeds for livestock, replacing in this role the type of maize that has been grown for this purpose until now. A great advantage of waxy maize is its specific structure of starch, due to its unique and high amylopectin content (95-98%, which creates unlimited possibilities of industrial use. Currently, waxy maize acreage in Europe does not exceed 2% of the maize crop area in this continent.

Rhizosphere acidification of faba bean, soybean and maize

Energy Technology Data Exchange (ETDEWEB)

Zhou, L.L. [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China); Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100094 (China); Cao, J. [School of Life Science, Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000 (China); Zhang, F.S. [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China); Li, L., E-mail: lilong@cau.edu.cn [College of Resources and Environmental Sciences, China Agricultural University, Key Laboratory of Plant and Soil Interactions, Ministry of Education, Beijing, 100094 (China)

2009-07-01

Interspecific facilitation on phosphorus uptake was observed in faba bean/maize intercropping systems in previous studies. The mechanism behind this, however, remained unknown. Under nitrate supply, the difference in rhizosphere acidification potential was studied by directly measuring pH of the solution and by visualizing and quantifying proton efflux of roots between faba bean (Vicia faba L. cv. Lincan No.5), soybean (Glycine max L. cv. Zhonghuang No. 17) and maize (Zea mays L. cv. Zhongdan No.2) in monoculture and intercrop, supplied without or with 0.2 mmol L{sup -1} P as KH{sub 2}PO{sub 4}. The pH of the nutrient solution grown faba bean was lower than initial pH of 6.0 from day 1 to day 22 under P deficiency, whereas the pH of the solution with maize was declined from day 13 after treatment. Growing soybean increased solution pH irrespective of P supply. Under P deficiency, the proton efflux of faba bean both total (315.25 nmol h{sup -1} plant{sup -1}) and specific proton efflux (0.47 nmol h{sup -1} cm{sup -1}) was greater than that those of soybean (21.80 nmol h{sup -1} plant{sup -1} and 0.05 nmol h{sup -1} cm{sup -1}, respectively). Faba bean had much more ability of rhizosphere acidification than soybean and maize. The result can explain partly why faba bean utilizes sparingly soluble P more effectively than soybean and maize do, and has an important implication in understanding the mechanism behind interspecific facilitation on P uptake by intercropped species.

Cell type-specific termination of transcription by transposable element sequences.

Science.gov (United States)

Conley, Andrew B; Jordan, I King

2012-09-30

Transposable elements (TEs) encode sequences necessary for their own transposition, including signals required for the termination of transcription. TE sequences within the introns of human genes show an antisense orientation bias, which has been proposed to reflect selection against TE sequences in the sense orientation owing to their ability to terminate the transcription of host gene transcripts. While there is evidence in support of this model for some elements, the extent to which TE sequences actually terminate transcription of human gene across the genome remains an open question. Using high-throughput sequencing data, we have characterized over 9,000 distinct TE-derived sequences that provide transcription termination sites for 5,747 human genes across eight different cell types. Rarefaction curve analysis suggests that there may be twice as many TE-derived termination sites (TE-TTS) genome-wide among all human cell types. The local chromatin environment for these TE-TTS is similar to that seen for 3' UTR canonical TTS and distinct from the chromatin environment of other intragenic TE sequences. However, those TE-TTS located within the introns of human genes were found to be far more cell type-specific than the canonical TTS. TE-TTS were much more likely to be found in the sense orientation than other intragenic TE sequences of the same TE family and TE-TTS in the sense orientation terminate transcription more efficiently than those found in the antisense orientation. Alu sequences were found to provide a large number of relatively weak TTS, whereas LTR elements provided a smaller number of much stronger TTS. TE sequences provide numerous termination sites to human genes, and TE-derived TTS are particularly cell type-specific. Thus, TE sequences provide a powerful mechanism for the diversification of transcriptional profiles between cell types and among evolutionary lineages, since most TE-TTS are evolutionarily young. The extent of transcription

Integrated database for identifying candidate genes for Aspergillus flavus resistance in maize.

Science.gov (United States)

Kelley, Rowena Y; Gresham, Cathy; Harper, Jonathan; Bridges, Susan M; Warburton, Marilyn L; Hawkins, Leigh K; Pechanova, Olga; Peethambaran, Bela; Pechan, Tibor; Luthe, Dawn S; Mylroie, J E; Ankala, Arunkanth; Ozkan, Seval; Henry, W B; Williams, W P

2010-10-07

Aspergillus flavus Link:Fr, an opportunistic fungus that produces aflatoxin, is pathogenic to maize and other oilseed crops. Aflatoxin is a potent carcinogen, and its presence markedly reduces the value of grain. Understanding and enhancing host resistance to A. flavus infection and/or subsequent aflatoxin accumulation is generally considered an efficient means of reducing grain losses to aflatoxin. Different proteomic, genomic and genetic studies of maize (Zea mays L.) have generated large data sets with the goal of identifying genes responsible for conferring resistance to A. flavus, or aflatoxin. In order to maximize the usage of different data sets in new studies, including association mapping, we have constructed a relational database with web interface integrating the results of gene expression, proteomic (both gel-based and shotgun), Quantitative Trait Loci (QTL) genetic mapping studies, and sequence data from the literature to facilitate selection of candidate genes for continued investigation. The Corn Fungal Resistance Associated Sequences Database (CFRAS-DB) (http://agbase.msstate.edu/) was created with the main goal of identifying genes important to aflatoxin resistance. CFRAS-DB is implemented using MySQL as the relational database management system running on a Linux server, using an Apache web server, and Perl CGI scripts as the web interface. The database and the associated web-based interface allow researchers to examine many lines of evidence (e.g. microarray, proteomics, QTL studies, SNP data) to assess the potential role of a gene or group of genes in the response of different maize lines to A. flavus infection and subsequent production of aflatoxin by the fungus. CFRAS-DB provides the first opportunity to integrate data pertaining to the problem of A. flavus and aflatoxin resistance in maize in one resource and to support queries across different datasets. The web-based interface gives researchers different query options for mining the database

Provitamin A-biofortified maize consumption increases serum xanthophylls and 13C-natural abundance of retinol in Zambian children.

Science.gov (United States)

Sheftel, Jesse; Gannon, Bryan M; Davis, Christopher R; Tanumihardjo, Sherry A

2017-09-01

Plants that undergo C 4 photosynthesis, such as maize, are enriched in the stable isotope of carbon ( 13 C) compared with other dietary plants and foods. Consumption of maize that has been biofortified to contain elevated levels of provitamin A carotenoids (orange maize) increased the abundance of 13 C in serum retinol of Mongolian gerbils. We evaluated this method in humans to determine if it has potential for further use in intervention effectiveness studies. A random subset of samples from a two-month randomized controlled feeding trial of rural three- to five-year old Zambian children were used to determine the impact of orange maize intake on serum carotenoid concentrations ( n = 88) and 13 C-natural abundance in serum retinol ( n = 77). Concentrations of β-cryptoxanthin (a xanthophyll provitamin A carotenoid) and the dihydroxy xanthophylls lutein and zeaxanthin, which do not have vitamin A activity, were elevated in children consuming orange maize compared with those consuming a white maize control ( P  0.3). Furthermore, 13 C natural abundance was higher after two months' intervention in the orange maize group compared with the white maize group ( P = 0.049). Predictions made from equations developed in the aforementioned gerbil study estimated that maize provided 11% (2-21%, 95% confidence interval) of the recent dietary vitamin A to these children. These results demonstrate that orange maize is efficacious at providing retinol to the vitamin A pool in children through provitamin A carotenoids, as monitored by the change in 13 C enrichment, which was not reflected in serum β-carotene concentrations. Further effectiveness studies in countries who have adopted orange maize should consider determining differences in retinol 13 C-enrichment among target groups in addition to profiling serum xanthophyll carotenoids with specific emphasis on zeaxanthin. Impact statement Maize biofortified with provitamin A carotenoids (orange) has been released

Root-type-specific plasticity in response to localized high nitrate supply in maize (Zea mays).

Science.gov (United States)

Yu, Peng; Hochholdinger, Frank; Li, Chunjian

2015-10-01

Shoot-borne roots contribute to most of the nutrient uptake throughout the life cycle of maize (Zea mays). Compared with numerous studies with embryonic roots, detailed information on the phenotypic plasticity of shoot-borne roots in response to a heterogeneous nitrogen supply is scarce. The present study therefore provides a comprehensive profile of fine-scale plastic responses of distinct root types to localized high nitrate supply. Seedlings of the maize inbred line B73 were grown in split-root systems. The anatomy and morphological plasticity of the primary root and the roots initiated from the 2nd, 5th and 7th shoot nodes, and their lateral roots, were studied in response to local high nitrate supply to one side of the root system. In contrast to the insensitivity of axial roots, local high nitrate supply increased the length of 1st-order lateral roots on the primary root and the three whorls of shoot-borne roots at different growth stages, and increased the density of 1st-order lateral roots on the 7th shoot-borne root after silking. The length and density of 2nd-order lateral roots on the three whorls of shoot-borne roots displayed a more flexible response to local high nitrate than 1st-order lateral roots. Root diameter and number, and total area and diameter of metaxylem vessels increased from the primary root to early and then later developed shoot-borne roots, which showed a positive relationship with shoot growth and N accumulation. Maize axial roots and lateral roots responded differently to local high nitrate, and this was related to their function. The extent of morphological plasticity of lateral roots in response to local high nitrate depended on the initiation time of the shoot-borne roots on which the lateral roots developed. Morphological plasticity was higher on 2nd-order than on 1st-order lateral roots. The results suggest that higher order lateral root branching might be a potential target for genetic improvement in future maize breeding. �

"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...

Comparative Analysis of CDPK Family in Maize, Arabidopsis, Rice, and Sorghum Revealed Potential Targets for Drought Tolerance Improvement

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Shikha Mittal

2017-12-01

Full Text Available Calcium dependent protein kinases (CDPKs play significant role in regulation of plant growth and development in response to various stresses including drought. A set of 32 CDPK genes identified in maize were further used for searching of orthologs in the model plant Arabidopsis (72 and major food crops such as rice (78 and sorghum (91. We comprehensively studied the phylogenetic relationship, annotations, gene duplications, gene structure, divergence time, 3-D protein structures and tissue-specific drought induced expression of CDPK genes in all four species. Variation in intron frequency in the studied species was one of the reasons for the functional diversity of CDPK genes to various stress responses. Protein kinase and protein kinase C phosphorylation site domains were the most conserved motifs identified in all species. Four groups were identified from the sequence-based phylogenetic analysis, in which maize CDPKs were clustered in group III. Expression data showed that the CDPK genes were highly expressed in leaf of maize, rice, and sorghum whereas in Arabidopsis the maximum expression was observed in root. The expression assay showed 5, 6, 11, and 9 were the commonly and differentially expressed drought-related orthologous genes in maize, Arabidopsis, rice, and sorghum, respectively. 3-D protein structure were predicted for the nine genes (Arabidopsis: 2, maize: 2, rice: 3, and sorghum: 2 showing differential expression in at least three species. The predicted 3-D structures were further evaluated and validated by Ramachandran plot, ANOLEA, ProSA, and Verify-3D. The superimposed 3-D structure of drought-related orthologous proteins retained similar folding pattern owing to their conserved nature. Functional annotation revealed the involvement of CDPK genes in various pathways such as osmotic homeostasis, cell protection, and root growth. The interactions of CDPK genes in various pathways play crucial role in imparting drought tolerance

Exploring the Bacterial Microbiota of Colombian Fermented Maize Dough "Masa Agria" (Maiz Añejo).

Science.gov (United States)

Chaves-Lopez, Clemencia; Serio, Annalisa; Delgado-Ospina, Johannes; Rossi, Chiara; Grande-Tovar, Carlos D; Paparella, Antonello

2016-01-01

Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 log CFU/g of presumptive lactic acid bacteria, 5.4 log cfu/g for presumptive acetic bacteria and 5.6 og CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1-3.7) registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella, and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by L. fermentum, L. vaccinostercus, and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favor microbial biodiversity characterized by a useful technological potential.

Extreme Weather Impacts on Maize Yield: The Case of Shanxi Province in China

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Taoyuan Wei

2016-12-01

Full Text Available Extreme weather can have negative impacts on crop production. In this study, we statistically estimate the impacts of dry days, heat waves, and cold days on maize yield based on household survey data from 1993 to 2011 in ten villages of Shanxi province, China. Our results show that dry days, heat waves, and cold days have negative effects on maize yield, although these effects are marginal if these extreme events do not increase dramatically. Specifically, a one percent increase in extreme-heat-degree-days and consecutive-dry-days results in a maize yield declines of 0.2% and 0.07%, respectively. Maize yield also is reduced by 0.3% for cold days occurring during the growing season from May to September. However, these extreme events can increase dramatically in a warmer world and result in considerable reduction in maize yields. If all the historical temperatures in the villages are shifted up by 2 degrees Celsius, total impacts of these extreme events would lead to a reduction of maize yield by over 30 percent. The impacts may be underestimated since we did not exclude the offset effect of adaptation measures adopted by farmers to combat these extreme events.

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

Comparative analysis of CDPK family in maize, Arabidopsis, rice and sorghum revealed potential targets for drought tolerance improvement

Science.gov (United States)

Mittal, Shikha; Mallikarjuna, Mallana Gowdra; Rao, Atmakuri R.; Jain, Prashant A.; Dash, Prasanta K.; Thirunavukkarasu, Nepolean

2017-12-01

Calcium dependent protein kinases (CDPKs) play major role in regulation of plant growth and development in response to various stresses including drought. A set of 32 CDPK genes identified in maize were further used for searching of orthologs in the model plant Arabidopsis (72) and major food crops such as rice (78) and sorghum (91). We comprehensively investigated the phylogenetic relationship, annotations, gene duplications, gene structure, divergence time, 3-D protein structures and tissue-specific drought induced expression of CDPK genes in all four species. Variation in intron frequency among these species likely contributed to the functional diversity of CDPK genes to various stress responses. Protein kinase and protein kinase C phosphorylation site domains were the most conserved motifs identified in all species. Four groups were identified from the sequence-based phylogenetic analysis, in which maize CDPKs were clustered in group III. The time of divergence (Ka/Ks) analysis revealed that the CDPKs were evolved through stabilizing selection. Expression data showed that the CDPK genes were highly expressed in leaf of maize, rice, and sorghum whereas in Arabidopsis the maximum expression was observed in root. 3-D protein structure were predicted for the nine genes (Arabidopsis: 2, maize: 2, rice: 3 and sorghum: 2) showing differential expression in at least three species. The predicted 3-D structures were further evaluated and validated by Ramachandran plot, ANOLEA, ProSA and Verify-3D. The superimposed 3-D structure of drought-related orthologous proteins retained similar folding pattern owing to their conserved nature. Functional annotation revealed the involvement of CDPK genes in various pathways such as osmotic homeostasis, cell protection and root growth. The interactions of CDPK genes in various pathways play crucial role in imparting drought tolerance through different ABA and MAPK signalling cascades. Our studies suggest that these selected candidate

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

It is expected that the ongoing anthropogenic climate change will drive changes in agricultural production and its geographic distribution. Here, we assess the extent to which climate change is already driving spatiotemporal dynamics in maize production in Denmark. We use advanced spatial...... regression modeling with multi-model averaging to assess the extent to which the recent spatiotemporal dynamics of the maize area in Denmark are driven by climate (temperature as represented by maize heating units [MHU] and growing-season precipitation), climate change and non-climatic factors (cattle...... cultivation and cattle farming, probably reflecting a change to a more favorable climate for maize cultivation: in the beginning of the study period, northern areas were mostly too cold for maize cultivation, irrespective of cattle density, but this limitation has been diminishing as climate has warmed...

Tracking maize pollen development by the Leaf Collar Method.

Science.gov (United States)

Begcy, Kevin; Dresselhaus, Thomas

2017-12-01

An easy and highly reproducible nondestructive method named the Leaf Collar Method is described to identify and characterize the different stages of pollen development in maize. In plants, many cellular events such as meiosis, asymmetric cell division, cell cycle regulation, cell fate determination, nucleus movement, vacuole formation, chromatin condensation and epigenetic modifications take place during pollen development. In maize, pollen development occurs in tassels that are confined within the internal stalk of the plant. Hence, identification of the different pollen developmental stages as a tool to investigate above biological processes is impossible without dissecting the entire plant. Therefore, an efficient and reproducible method is necessary to isolate homogeneous cell populations at individual stages throughout pollen development without destroying the plant. Here, we describe a method to identify the various stages of pollen development in maize. Using the Leaf Collar Method in the maize inbreed line B73, we have determined the duration of each stage from pollen mother cells before meiosis to mature tricellular pollen. Anther and tassel size as well as percentage of pollen stages were correlated with vegetative stages, which are easily recognized. The identification of stage-specific genes indicates the reproducibility of the method. In summary, we present an easy and highly reproducible nondestructive method to identify and characterize the different stages of pollen development in maize. This method now opens the way for many subsequent physiological, morphological and molecular analyses to study, for instance, transcriptomics, metabolomics, DNA methylation and chromatin patterns during normal and stressful conditions throughout pollen development in one of the economically most important grass species.

The effect of feeding Bt MON810 maize to pigs for 110 days on intestinal microbiota.

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Stefan G Buzoianu

Full Text Available OBJECTIVE: To assess the effects of feeding Bt MON810 maize to pigs for 110 days on the intestinal microbiota. METHODOLOGY/PRINCIPAL FINDINGS: Forty male pigs (∼40 days old were blocked by weight and litter ancestry and assigned to one of four treatments; 1 Isogenic maize-based diet for 110 days (Isogenic; 2 Bt maize-based diet (MON810 for 110 days (Bt; 3 Isogenic maize-based diet for 30 days followed by a Bt maize-based diet for 80 days (Isogenic/Bt; 4 Bt maize-based diet for 30 days followed by an isogenic maize-based diet for 80 days (Bt/Isogenic. Enterobacteriaceae, Lactobacillus and total anaerobes were enumerated in the feces using culture-based methods on days 0, 30, 60 and 100 of the study and in ileal and cecal digesta on day 110. No differences were found between treatments for any of these counts at any time point. The relative abundance of cecal bacteria was also determined using high-throughput 16 S rRNA gene sequencing. No differences were observed in any bacterial taxa between treatments, with the exception of the genus Holdemania which was more abundant in the cecum of pigs fed the isogenic/Bt treatment compared to pigs fed the Bt treatment (0.012 vs 0.003%; P≤0.05. CONCLUSIONS/SIGNIFICANCE: Feeding pigs a Bt maize-based diet for 110 days did not affect counts of any of the culturable bacteria enumerated in the feces, ileum or cecum. Neither did it influence the composition of the cecal microbiota, with the exception of a minor increase in the genus Holdemania. As the role of Holdemania in the intestine is still under investigation and no health abnormalities were observed, this change is not likely to be of clinical significance. These results indicate that feeding Bt maize to pigs in the context of its influence on the porcine intestinal microbiota is safe.

TasselNet: counting maize tassels in the wild via local counts regression network.

Science.gov (United States)

Lu, Hao; Cao, Zhiguo; Xiao, Yang; Zhuang, Bohan; Shen, Chunhua

2017-01-01

performance, with a mean absolute error of 6.6 and a mean squared error of 9.6 averaged over 8 test sequences. TasselNet can achieve robust in-field counting of maize tassels with a relatively high degree of accuracy. Our experimental evaluations also suggest several good practices for practitioners working on maize-tassel-like counting problems. It is worth noting that, though the counting errors have been greatly reduced by TasselNet, in-field counting of maize tassels remains an open and unsolved problem.

TasselNet: counting maize tassels in the wild via local counts regression network

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Hao Lu

2017-11-01

margins and achieves the overall best counting performance, with a mean absolute error of 6.6 and a mean squared error of 9.6 averaged over 8 test sequences. Conclusions TasselNet can achieve robust in-field counting of maize tassels with a relatively high degree of accuracy. Our experimental evaluations also suggest several good practices for practitioners working on maize-tassel-like counting problems. It is worth noting that, though the counting errors have been greatly reduced by TasselNet, in-field counting of maize tassels remains an open and unsolved problem.

Identification and expression profiling analysis of TCP family genes involved in growth and development in maize.

Science.gov (United States)

Chai, Wenbo; Jiang, Pengfei; Huang, Guoyu; Jiang, Haiyang; Li, Xiaoyu

2017-10-01

The TCP family is a group of plant-specific transcription factors. TCP genes encode proteins harboring bHLH structure, which is implicated in DNA binding and protein-protein interactions and known as the TCP domain. TCP genes play important roles in plant development and have been evolutionarily and functionally elaborated in various plants, however, no overall phylogenetic analysis or expression profiling of TCP genes in Zea mays has been reported. In the present study, a systematic analysis of molecular evolution and functional prediction of TCP family genes in maize ( Z . mays L.) has been conducted. We performed a genome-wide survey of TCP genes in maize, revealing the gene structure, chromosomal location and phylogenetic relationship of family members. Microsynteny between grass species and tissue-specific expression profiles were also investigated. In total, 29 TCP genes were identified in the maize genome, unevenly distributed on the 10 maize chromosomes. Additionally, ZmTCP genes were categorized into nine classes based on phylogeny and purifying selection may largely be responsible for maintaining the functions of maize TCP genes. What's more, microsynteny analysis suggested that TCP genes have been conserved during evolution. Finally, expression analysis revealed that most TCP genes are expressed in the stem and ear, which suggests that ZmTCP genes influence stem and ear growth. This result is consistent with the previous finding that maize TCP genes represses the growth of axillary organs and enables the formation of female inflorescences. Altogether, this study presents a thorough overview of TCP family in maize and provides a new perspective on the evolution of this gene family. The results also indicate that TCP family genes may be involved in development stage in plant growing conditions. Additionally, our results will be useful for further functional analysis of the TCP gene family in maize.

Weed diversity identification on growth phases of twelve maize varieties

Science.gov (United States)

Rahayu, M.; Yudono, P.; Indradewa, D.; Hanudin, E.

2018-03-01

Weed is one of the factors that disturb maize cultivation. Each maize variety has specific characteristics which will lead to weeds diversity in particular farm. This study aimed to identify the effect of maize variety on weed diversity on maize’s growth phases. The research was conducted from March to July 2016 in Banguntapan, Bantul, Yogyakarta, Indonesia. The field research was arranged by using Randomised Complete Block Design with three replications. The treatments were maize varieties, consist of 12 levels: ‘Bisi 18’, ‘Bisi 2’, ‘Pertiwi 3’, ‘NK 22’, ‘NK 33’, ‘DK 959’, ‘P23’, ‘DK 771’, ‘DK 95’, ‘Bima 19 Uri’, ‘Bisma’, and ‘Sukmaraga’. The results showed that at four weeks after planting (WAP) the most of weeds were growing on varieties ‘Bisi 18’, ‘NK 33’, ‘P 23’, and ‘DK 95’, there were 14 species. Bulbostylispuberula and Cyperusrotundus were growing on all maize varieties with the highest SDR on ‘Sukmaraga’ and ‘DK 959’. At six WAP, weeds that grew, most consists of four species of sedges, six species of grasses and 24 species of broadleaf. While at the age of eight WAP, the weeds that grow at least on ‘NK 33’ that were 13 species and the most on ‘P23’ that were 21 species. Dactyloctenium aeghypthium having highest SDR in all maize varieties except Bisi 18. The highest SDR value on Bisi 18 was Boerhaavia erecta about 16.23%.

Sequence-specific RNA Photocleavage by Single-stranded DNA in Presence of Riboflavin

Science.gov (United States)

Zhao, Yongyun; Chen, Gangyi; Yuan, Yi; Li, Na; Dong, Juan; Huang, Xin; Cui, Xin; Tang, Zhuo

2015-10-01

Constant efforts have been made to develop new method to realize sequence-specific RNA degradation, which could cause inhibition of the expression of targeted gene. Herein, by using an unmodified short DNA oligonucleotide for sequence recognition and endogenic small molecue, vitamin B2 (riboflavin) as photosensitizer, we report a simple strategy to realize the sequence-specific photocleavage of targeted RNA. The DNA strand is complimentary to the target sequence to form DNA/RNA duplex containing a G•U wobble in the middle. The cleavage reaction goes through oxidative elimination mechanism at the nucleoside downstream of U of the G•U wobble in duplex to obtain unnatural RNA terminal, and the whole process is under tight control by using light as switch, which means the cleavage could be carried out according to specific spatial and temporal requirements. The biocompatibility of this method makes the DNA strand in combination with riboflavin a promising molecular tool for RNA manipulation.

Discrimination of the Lactobacillus acidophilus group using sequencing, species-specific PCR and SNaPshot mini-sequencing technology based on the recA gene.

Science.gov (United States)

Huang, Chien-Hsun; Chang, Mu-Tzu; Huang, Mu-Chiou; Wang, Li-Tin; Huang, Lina; Lee, Fwu-Ling

2012-10-01

To clearly identify specific species and subspecies of the Lactobacillus acidophilus group using phenotypic and genotypic (16S rDNA sequence analysis) techniques alone is difficult. The aim of this study was to use the recA gene for species discrimination in the L. acidophilus group, as well as to develop a species-specific primer and single nucleotide polymorphism primer based on the recA gene sequence for species and subspecies identification. The average sequence similarity for the recA gene among type strains was 80.0%, and most members of the L. acidophilus group could be clearly distinguished. The species-specific primer was designed according to the recA gene sequencing, which was employed for polymerase chain reaction with the template DNA of Lactobacillus strains. A single 231-bp species-specific band was found only in L. delbrueckii. A SNaPshot mini-sequencing assay using recA as a target gene was also developed. The specificity of the mini-sequencing assay was evaluated using 31 strains of L. delbrueckii species and was able to unambiguously discriminate strains belonging to the subspecies L. delbrueckii subsp. bulgaricus. The phylogenetic relationships of most strains in the L. acidophilus group can be resolved using recA gene sequencing, and a novel method to identify the species and subspecies of the L. delbrueckii and L. delbrueckii subsp. bulgaricus was developed by species-specific polymerase chain reaction combined with SNaPshot mini-sequencing. Copyright © 2012 Society of Chemical Industry.

Infecção mista pelo Sugarcane mosaic virus e Maize rayado fino virus provoca danos na cultura do milho no estado de São Paulo Mixed infection by Sugarcane mosaic virus and Maize rayado fino virus causing breaking yields in maize in São Paulo state

Directory of Open Access Journals (Sweden)

Marcos César Gonçalves

2007-12-01

Full Text Available Os dois principais vírus que infectam o milho no Brasil são o Sugarcane mosaic virus (SCMV e o Maize rayado fino virus (MRFV, cujos principais vetores são o afídeo Rhopalosiphum maidis e a cigarrinha Dalbulus maidis, respectivamente. O MRFV é freqüentemente encontrado em infecções mistas com fitoplasmas e espiroplasmas, causando as doenças denominadas enfezamentos do milho. Em uma lavoura de milho próxima a Santo Antonio da Posse, SP, cercada por campos de cana-de-açúcar, foi encontrada alta incidência de plantas apresentando mosaico, riscas, nanismo e espigas com falhas no enchimento de grãos. Análises serológicas com anti-soros específicos detectaram a presença do SCMV e MRFV nessas plantas. A infecção pelo SCMV também foi confirmada por RT-PCR com primers específicos e análise de seqüências. Em observações de preparações contrastadas negativamente em TEM, partículas flexuosas (ca.770 nm e isométricas (ca.30 nm foram detectadas. Em cortes ultrafinos, inclusões citoplasmáticas, típicas de Potyviridae, foram observadas; não foi encontrada a presença de espiroplasmas nem de fitoplasmas. Esses resultados mostram que a infecção conjunta por SCMV e MRFV pode ser responsável pelos danos encontrados nessa lavoura.The two main viruses infecting maize in Brazil are Sugarcane mosaic virus (SCMV and Maize rayado fino virus (MRFV, whose main vectors are the aphid Rhopalosiphum maidis and the leafhopper Dalbulus maidis, respectively. MRFV is frequently found in mixed infections with phytoplasms and spiroplasms causing the so-called corn stunting diseases. In a maize commercial field close to Santo Antonio da Posse, São Paulo state, surrounded by sugarcane fields, it was found a high incidence of plants showing mosaic, striping, stunting and cobs with decreased number of grains. Serological analysis with specific antisera detected the presence of SCMV and MRFV in these plants. SCMV infection was also confirmed by RT

Past and prospects of forage maize breeding in Europe. II. History, germplasm evolution and correlative agronomic changes

NARCIS (Netherlands)

Barriere, Y.; Alber, D.; Dolstra, O.; Lapierre, C.; Motto, M.; Ordas, A.; Waes, Van J.; Vlasminkel, L.; Welcker, C.; Monod, J.P.

2006-01-01

Although maize was early recognized as an excellent forage plant soon after its introduction in Europe, during a long time it was only bred for grain traits. However, the first recommendations of maize varieties for specific forage use are probably those given in the French VILMORIN-ANDRIEUX

Identification and phylogenetic analysis of a novel starch synthase in maize

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Hanmei eLiu

2015-11-01

Full Text Available Starch is an important reserve of carbon and energy in plants, providing the majority of calories in the human diet and animal feed. Its synthesis is orchestrated by several key enzymes, and the amount and structure of starch, affecting crop yield and quality, are determined mainly by starch synthase (SS activity. To date, five SS isoforms, including SSI-IV and Granule Bound Starch Synthase (GBSS have been identified and their physiological functions have been well characterized. Here, we report the identification of a new SS isoform in maize, designated SSV. By searching sequenced genomes, SSV has been found in all green plants with conserved sequences and gene structures. Our phylogenetic analysis based on 780 base pairs has suggested that SSIV and SSV resulted from a gene duplication event, which may have occurred before the algae formation. An expression profile analysis of SSV in maize has indicated that ZmSSV is mainly transcribed in the kernel and ear leaf during the grain filling stage, which is partly similar to other SS isoforms. Therefore, it is likely that SSV may play an important role in starch biosynthesis. Subsequent analysis of SSV function may facilitate understanding the mechanism of starch granules formation, number and structure.

Rapid Cycling Genomic Selection in a Multiparental Tropical Maize Population.

Science.gov (United States)

Zhang, Xuecai; Pérez-Rodríguez, Paulino; Burgueño, Juan; Olsen, Michael; Buckler, Edward; Atlin, Gary; Prasanna, Boddupalli M; Vargas, Mateo; San Vicente, Félix; Crossa, José

2017-07-05

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 the first to show realized genetic gains of rapid cycling genomic selection (RCGS) for four recombination cycles in a multi-parental tropical maize population. Eighteen elite tropical maize lines were intercrossed twice, and self-pollinated once, to form the cycle 0 (C 0 ) training population. A total of 1000 ear-to-row C 0 families was genotyped with 955,690 genotyping-by-sequencing SNP markers; their testcrosses were phenotyped at four optimal locations in Mexico to form the training population. Individuals from families with the best plant types, maturity, and grain yield were selected and intermated to form RCGS cycle 1 (C 1 ). Predictions of the genotyped individuals forming cycle C 1 were made, and the best predicted grain yielders were selected as parents of C 2 ; this was repeated for more cycles (C 2 , C 3 , and C 4 ), thereby achieving two cycles per year. Multi-environment trials of individuals from populations C 0, C 1 , C 2 , C 3 , and C 4 , together with four benchmark checks were evaluated at two locations in Mexico. Results indicated that realized grain yield from C 1 to C 4 reached 0.225 ton ha -1 per cycle, which is equivalent to 0.100 ton ha -1  yr -1 over a 4.5-yr breeding period from the initial cross to the last cycle. Compared with the original 18 parents used to form cycle 0 (C 0 ), genetic diversity narrowed only slightly during the last GS cycles (C 3 and C 4 ). Results indicate that, in tropical maize multi-parental breeding populations, RCGS can be an effective breeding strategy for simultaneously conserving genetic diversity and achieving high genetic gains in a short period of time. Copyright © 2017 Zhang et al.

Cell type-specific termination of transcription by transposable element sequences

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Conley Andrew B

2012-09-01

Full Text Available Abstract Background Transposable elements (TEs encode sequences necessary for their own transposition, including signals required for the termination of transcription. TE sequences within the introns of human genes show an antisense orientation bias, which has been proposed to reflect selection against TE sequences in the sense orientation owing to their ability to terminate the transcription of host gene transcripts. While there is evidence in support of this model for some elements, the extent to which TE sequences actually terminate transcription of human gene across the genome remains an open question. Results Using high-throughput sequencing data, we have characterized over 9,000 distinct TE-derived sequences that provide transcription termination sites for 5,747 human genes across eight different cell types. Rarefaction curve analysis suggests that there may be twice as many TE-derived termination sites (TE-TTS genome-wide among all human cell types. The local chromatin environment for these TE-TTS is similar to that seen for 3′ UTR canonical TTS and distinct from the chromatin environment of other intragenic TE sequences. However, those TE-TTS located within the introns of human genes were found to be far more cell type-specific than the canonical TTS. TE-TTS were much more likely to be found in the sense orientation than other intragenic TE sequences of the same TE family and TE-TTS in the sense orientation terminate transcription more efficiently than those found in the antisense orientation. Alu sequences were found to provide a large number of relatively weak TTS, whereas LTR elements provided a smaller number of much stronger TTS. Conclusions TE sequences provide numerous termination sites to human genes, and TE-derived TTS are particularly cell type-specific. Thus, TE sequences provide a powerful mechanism for the diversification of transcriptional profiles between cell types and among evolutionary lineages, since most TE-TTS are

Whole-genome in-silico subtractive hybridization (WISH - using massive sequencing for the identification of unique and repetitive sex-specific sequences: the example of Schistosoma mansoni

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Parrinello Hugues

2010-06-01

Full Text Available Abstract Background Emerging methods of massive sequencing that allow for rapid re-sequencing of entire genomes at comparably low cost are changing the way biological questions are addressed in many domains. Here we propose a novel method to compare two genomes (genome-to-genome comparison. We used this method to identify sex-specific sequences of the human blood fluke Schistosoma mansoni. Results Genomic DNA was extracted from male and female (heterogametic S. mansoni adults and sequenced with a Genome Analyzer (Illumina. Sequences are available at the NCBI sequence read archive http://www.ncbi.nlm.nih.gov/Traces/sra/ under study accession number SRA012151.6. Sequencing reads were aligned to the genome, and a pseudogenome composed of known repeats. Straightforward comparative bioinformatics analysis was performed to compare male and female schistosome genomes and identify female-specific sequences. We found that the S. mansoni female W chromosome contains only few specific unique sequences (950 Kb i.e. about 0.2% of the genome. The majority of W-specific sequences are repeats (10.5 Mb i.e. about 2.5% of the genome. Arbitrarily selected W-specific sequences were confirmed by PCR. Primers designed for unique and repetitive sequences allowed to reliably identify the sex of both larval and adult stages of the parasite. Conclusion Our genome-to-genome comparison method that we call "whole-genome in-silico subtractive hybridization" (WISH allows for rapid identification of sequences that are specific for a certain genotype (e.g. the heterogametic sex. It can in principle be used for the detection of any sequence differences between isolates (e.g. strains, pathovars or even closely related species.

Nostoc PCC7524, a cyanobacterium which contains five sequence-specific deoxyribonucleases

NARCIS (Netherlands)

Reaston, J.; Duybesteyn, M.G.C.; Waard, Adrian de

1982-01-01

Five nucleotide sequence-specific deoxyribonucleases present in cell-free extracts of the filamentous cyanobacterium Nostoc PCC7524 have been purified and characterized. One of these enzymes, designated Nsp(7524)I cleaves at a new kind of nucleotide sequence i.e. 5'-PuCATG λ Py-3'. The other four

Specific Deficit in Implicit Motor Sequence Learning following Spinal Cord Injury.

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Ayala Bloch

Full Text Available Physical and psychosocial rehabilitation following spinal cord injury (SCI leans heavily on learning and practicing new skills. However, despite research relating motor sequence learning to spinal cord activity and clinical observations of impeded skill-learning after SCI, implicit procedural learning following spinal cord damage has not been examined.To test the hypothesis that spinal cord injury (SCI in the absence of concomitant brain injury is associated with a specific implicit motor sequence learning deficit that cannot be explained by depression or impairments in other cognitive measures.Ten participants with SCI in T1-T11, unharmed upper limb motor and sensory functioning, and no concomitant brain injury were compared to ten matched control participants on measures derived from the serial reaction time (SRT task, which was used to assess implicit motor sequence learning. Explicit generation of the SRT sequence, depression, and additional measures of learning, memory, and intelligence were included to explore the source and specificity of potential learning deficits.There was no between-group difference in baseline reaction time, indicating that potential differences between the learning curves of the two groups could not be attributed to an overall reduction in response speed in the SCI group. Unlike controls, the SCI group showed no decline in reaction time over the first six blocks of the SRT task and no advantage for the initially presented sequence over the novel interference sequence. Meanwhile, no group differences were found in explicit learning, depression, or any additional cognitive measures.The dissociation between impaired implicit learning and intact declarative memory represents novel empirical evidence of a specific implicit procedural learning deficit following SCI, with broad implications for rehabilitation and adjustment.

First-order and higher order sequence learning in specific language impairment.

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Clark, Gillian M; Lum, Jarrad A G

2017-02-01

A core claim of the procedural deficit hypothesis of specific language impairment (SLI) is that the disorder is associated with poor implicit sequence learning. This study investigated whether implicit sequence learning problems in SLI are present for first-order conditional (FOC) and higher order conditional (HOC) sequences. Twenty-five children with SLI and 27 age-matched, nonlanguage-impaired children completed 2 serial reaction time tasks. On 1 version, the sequence to be implicitly learnt comprised a FOC sequence and on the other a HOC sequence. Results showed that the SLI group learned the HOC sequence (η p ² = .285, p = .005) but not the FOC sequence (η p ² = .099, p = .118). The control group learned both sequences (FOC η p ² = .497, HOC η p 2= .465, ps < .001). The SLI group's difficulty learning the FOC sequence is consistent with the procedural deficit hypothesis. However, the study provides new evidence that multiple mechanisms may underpin the learning of FOC and HOC sequences. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Pollen-Mediated Gene Flow in Maize: Implications for Isolation Requirements and Coexistence in Mexico, the Center of Origin of Maize.

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Baltazar, Baltazar M; Castro Espinoza, Luciano; Espinoza Banda, Armando; de la Fuente Martínez, Juan Manuel; Garzón Tiznado, José Antonio; González García, Juvencio; Gutiérrez, Marco Antonio; Guzmán Rodríguez, José Luis; Heredia Díaz, Oscar; Horak, Michael J; Madueño Martínez, Jesús Ignacio; Schapaugh, Adam W; Stojšin, Duška; Uribe Montes, Hugo Raúl; Zavala García, Francisco

2015-01-01

Mexico, the center of origin of maize (Zea mays L.), has taken actions to preserve the identity and diversity of maize landraces and wild relatives. Historically, spatial isolation has been used in seed production to maintain seed purity. Spatial isolation can also be a key component for a strategy to minimize pollen-mediated gene flow in Mexico between transgenic maize and sexually compatible plants of maize conventional hybrids, landraces, and wild relatives. The objective of this research was to generate field maize-to-maize outcrossing data to help guide coexistence discussions in Mexico. In this study, outcrossing rates were determined and modeled from eight locations in six northern states, which represent the most economically important areas for the cultivation of hybrid maize in Mexico. At each site, pollen source plots were planted with a yellow-kernel maize hybrid and surrounded by plots with a white-kernel conventional maize hybrid (pollen recipient) of the same maturity. Outcrossing rates were then quantified by assessing the number of yellow kernels harvested from white-kernel hybrid plots. The highest outcrossing values were observed near the pollen source (12.9% at 1 m distance). The outcrossing levels declined sharply to 4.6, 2.7, 1.4, 1.0, 0.9, 0.5, and 0.5% as the distance from the pollen source increased to 2, 4, 8, 12, 16, 20, and 25 m, respectively. At distances beyond 20 m outcrossing values at all locations were below 1%. These trends are consistent with studies conducted in other world regions. The results suggest that coexistence measures that have been implemented in other geographies, such as spatial isolation, would be successful in Mexico to minimize transgenic maize pollen flow to conventional maize hybrids, landraces and wild relatives.

Effect of different irrigation systems on root growth of maize and cowpea plants in sandy soil

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Noha A. Mahgoub

2017-10-01

Full Text Available A field experiment was conducted at the Experimental Farm, Faculty of Agriculture, Suez Canal University to study the influence of different irrigation systems on root length density and specific root length of maize and cowpea plants cultivated in sandy soil. Three irrigation systems (Surface, drip and sprinkler irrigation were used in this study. The NPK fertilizers were applied as recommended doses for maize and cowpea. Root samples were collected from the soil profile below one plant (maize and cowpea which was irrigated by the three irrigation systems by using an iron box (30 cm× 20 cm which is divided into 24 small boxes each box is (5× 5 × 5 cm. At surface irrigation, root length density of cowpea reached to soil depth 30-40cm with lateral distances 5-10 cm and 15-20 cm. Vertical distribution of root length density of maize was increased with soil depth till 20-25 cm, and then it decreased till soil depth 35-40cm. Under drip irrigation, root length density of cowpea increased horizontally from 0-5cm to 10-15cm then it decreased till soil depth 25-30 cm and below this depth root length density disappeared. For the root length density and specific root length of maize under drip irrigation, the data showed that root length density and specific root length decreased with increasing in soil depth. The root length density of cowpea under sprinkler irrigation at 0-5cm disappeared from horizontal distance at 25-30 cm. The data showed that root length density of maize under sprinkler irrigation was higher at the soil top layers 0-5 cm and 5-10 cm than other layers from 10-40 cm.

Green Gram Rotation Effects on Maize Growth Parameters and Soil Quality in Myanmar

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Myo Kywe

2008-10-01

Full Text Available At present maize–green gram crop rotations are not widely practiced among farmers in Myanmar. However, this cropping system might become more popular in the future given raising prices for green gram and maize grain and scarcity of mineral nitrogen (N fertilizers in this Asian country. The results of a cropping systems experiment with continuous maize versus a green gram-maize rotation, manure application (0 and 2 t ha−1 and phosphorus (P fertilization (0 and 15 kg P ha−1 in each of five consecutive seasons revealed a strong decline in total dry matter and grains yields for both crops irrespective of the treatment. Treatment effects on yield components, nutrient concentrations, mycorrhizal infection and nematode infestation were small or negligible. The data show that in addition to manure used at 2 t ha−1, application of mineral N fertilizers is essential to maintain particularly maize yields. A comparison of different green gram cultivars did not indicate genotype specific effects on maize growth. The incorporation of legume residues, unless they are used as animal feed, is recommended to increase the recycling of N and to balance N fluxes when green gram is cultivated for seed.

Core Promoter Plasticity Between Maize Tissues and Genotypes Contrasts with Predominance of Sharp Transcription Initiation Sites.

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Mejía-Guerra, María Katherine; Li, Wei; Galeano, Narmer F; Vidal, Mabel; Gray, John; Doseff, Andrea I; Grotewold, Erich

2015-12-01

Core promoters are crucial for gene regulation, providing blueprints for the assembly of transcriptional machinery at transcription start sites (TSSs). Empirically, TSSs define the coordinates of core promoters and other regulatory sequences. Thus, experimental TSS identification provides an essential step in the characterization of promoters and their features. Here, we describe the application of CAGE (cap analysis of gene expression) to identify genome-wide TSSs used in root and shoot tissues of two maize (Zea mays) inbred lines (B73 and Mo17). Our studies indicate that most TSS clusters are sharp in maize, similar to mice, but distinct from Arabidopsis thaliana, Drosophila melanogaster, or zebra fish, in which a majority of genes have broad-shaped TSS clusters. We established that ∼38% of maize promoters are characterized by a broader TATA-motif consensus, and this motif is significantly enriched in genes with sharp TSSs. A noteworthy plasticity in TSS usage between tissues and inbreds was uncovered, with ∼1500 genes showing significantly different dominant TSSs, sometimes affecting protein sequence by providing alternate translation initiation codons. We experimentally characterized instances in which this differential TSS utilization results in protein isoforms with additional domains or targeted to distinct subcellular compartments. These results provide important insights into TSS selection and gene expression in an agronomically important crop. © 2015 American Society of Plant Biologists. All rights reserved.

Polymorphisms in O-methyltransferase genes are associated with stover cell wall digestibility in European maize (Zea mays L.)

DEFF Research Database (Denmark)

Brenner, Everton A; Zein, Imad; Chen, Yongsheng

2010-01-01

Background OMT (O-methyltransferase) genes are involved in lignin biosynthesis, which relates to stover cell wall digestibility. Reduced lignin content is an important determinant of both forage quality and ethanol conversion efficiency of maize stover. Results Variation in genomic sequences codi...

Selection of Suitable DNA Extraction Methods for Genetically Modified Maize 3272, and Development and Evaluation of an Event-Specific Quantitative PCR Method for 3272.

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Takabatake, Reona; Masubuchi, Tomoko; Futo, Satoshi; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Teshima, Reiko; Kurashima, Takeyo; Mano, Junichi; Kitta, Kazumi

2016-01-01

A novel real-time PCR-based analytical method was developed for the event-specific quantification of a genetically modified (GM) maize, 3272. We first attempted to obtain genome DNA from this maize using a DNeasy Plant Maxi kit and a DNeasy Plant Mini kit, which have been widely utilized in our previous studies, but DNA extraction yields from 3272 were markedly lower than those from non-GM maize seeds. However, lowering of DNA extraction yields was not observed with GM quicker or Genomic-tip 20/G. We chose GM quicker for evaluation of the quantitative method. We prepared a standard plasmid for 3272 quantification. The conversion factor (Cf), which is required to calculate the amount of a genetically modified organism (GMO), was experimentally determined for two real-time PCR instruments, the Applied Biosystems 7900HT (the ABI 7900) and the Applied Biosystems 7500 (the ABI7500). The determined Cf values were 0.60 and 0.59 for the ABI 7900 and the ABI 7500, respectively. To evaluate the developed method, a blind test was conducted as part of an interlaboratory study. The trueness and precision were evaluated as the bias and reproducibility of the relative standard deviation (RSDr). The determined values were similar to those in our previous validation studies. The limit of quantitation for the method was estimated to be 0.5% or less, and we concluded that the developed method would be suitable and practical for detection and quantification of 3272.

Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

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Nengyi Zhang

2010-04-01

Full Text Available Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system.We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication.Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

No adjuvant effect of Bacillus thuringiensis-maize on allergic responses in mice.

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Daniela Reiner

Full Text Available Genetically modified (GM foods are evaluated carefully for their ability to induce allergic disease. However, few studies have tested the capacity of a GM food to act as an adjuvant, i.e. influencing allergic responses to other unrelated allergens at acute onset and in individuals with pre-existing allergy. We sought to evaluate the effect of short-term feeding of GM Bacillus thuringiensis (Bt-maize (MON810 on the initiation and relapse of allergic asthma in mice. BALB/c mice were provided a diet containing 33% GM or non-GM maize for up to 34 days either before ovalbumin (OVA-induced experimental allergic asthma or disease relapse in mice with pre-existing allergy. We observed that GM-maize feeding did not affect OVA-induced eosinophilic airway and lung inflammation, mucus hypersecretion or OVA-specific antibody production at initiation or relapse of allergic asthma. There was no adjuvant effect upon GM-maize consumption on the onset or severity of allergic responses in a mouse model of allergic asthma.

Regulatory elements in vivo in the promoter of the abscisic acid responsive gene rab17 from maize.

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Busk, P K; Jensen, A B; Pagès, M

1997-06-01

The rab17 gene from maize is transcribed in late embryonic development and is responsive to abscisic acid and water stress in embryo and vegetative tissues. In vivo footprinting and transient transformation of rab17 were performed in embryos and vegetative tissues to characterize the cis-elements involved in regulation of the gene. By in vivo footprinting, protein binding was observed to nine elements in the promoter, which correspond to five putative ABREs (abscisic acid responsive elements) and four other sequences. The footprints indicated that distinct proteins interact with these elements in the two developmental stages. In transient transformation, six of the elements were important for high level expression of the rab17 promoter in embryos, whereas only three elements were important in leaves. The cis-acting sequences can be divided in embryo-specific, ABA-specific and leaf-specific elements on the basis of protein binding and the ability to confer expression of rab17. We found one positive, new element, called GRA, with the sequence CACTGGCCGCCC. This element was important for transcription in leaves but not in embryos. Two other non-ABRE elements that stimulated transcription from the rab17 promoter resemble previously described abscisic acid and drought-inducible elements. There were differences in protein binding and function of the five ABREs in the rab17 promoter. The possible reasons for these differences are discussed. The in vivo data obtained suggest that an embryo-specific pathway regulates transcription of the rab genes during development, whereas another pathway is responsible for induction in response to ABA and drought in vegetative tissues.

The maize CorA/MRS2/MGT-type Mg transporter, ZmMGT10, responses to magnesium deficiency and confers low magnesium tolerance in transgenic Arabidopsis.

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Li, Hongyou; Wang, Ning; Ding, Jianzhou; Liu, Chan; Du, Hanmei; Huang, Kaifeng; Cao, Moju; Lu, Yanli; Gao, Shibin; Zhang, Suzhi

2017-10-01

ZmMGT10 was specifically expressed in maize roots and induced by a deficiency of magnesium. Overexpression of ZmMGT10 restored growth deficiency of the Salmonella typhimurium MM281 strain and enhanced the tolerance in Arabidopsis to stress induced by low magnesium levels by increasing uptake of Mg 2+ via roots. CorA/MRS2/MGT-type Mg 2+ transporters play a significant role in maintaining magnesium (Mg) homeostasis in plants. Although the maize CorA/MRS2/MGT family comprises of 12 members, currently no member has been functionally characterized. Here, we report the isolation and functional characterization of ZmMGT10 from the maize MRS2/MGT gene family. ZmMGT10 has a typical structure feature which includes two conserved TMs near the C-terminal end and an altered AMN tripeptide motif. The high sequence similarity and close phylogenetic relationship indicates that ZmMGT10 is probably the counterpart of Arabidopsis AtMGT6. The complementation of the Salmonella typhimurium mutated MM281 strain indicates that ZmMGT10 possesses the ability to transport Mg 2+ . ZmMGT10 was specifically expressed in the plant roots and it can be stimulated by a deficiency of Mg. Transgenic Arabidopsis plants which overexpressed ZmMGT10 grew more vigorously than wild-type plants under low Mg conditions, exhibited by longer root length, higher plant fresh weight and chlorophyll content, suggesting ZmMGT10 was essential for plant growth and development under low Mg conditions. Further investigations found that high accumulation of Mg 2+ occurred in transgenic plants attributed to improved Mg 2+ uptake and thereby enhanced tolerance to Mg deficiency. Results from this investigation illustrate that ZmMGT10 is a Mg transporter of maize which can enhance the tolerance to Mg deficient conditions by improving Mg 2+ uptake in the transgenic plants of Arabidopsis.

Effects of INH, DNP, 2, 4-D and CMU on the sugar content of the barley and maize leaves

International Nuclear Information System (INIS)

Fernandez, J.; Sancho, P.

1979-01-01

1 ppm of the chemicals in nutritive solution was absorbed by barley and maize roots during 24 and 48 hours in dark or light conditioners in order to determine the best conditions for the obtention of labelled sugars with high specific activity. Results show that the highest specific activity was obtained in maize plants treated with DNP for 24 hours in dark conditions. (Author) 51 refs

Automated sequence-specific protein NMR assignment using the memetic algorithm MATCH

International Nuclear Information System (INIS)

Volk, Jochen; Herrmann, Torsten; Wuethrich, Kurt

2008-01-01

MATCH (Memetic Algorithm and Combinatorial Optimization Heuristics) is a new memetic algorithm for automated sequence-specific polypeptide backbone NMR assignment of proteins. MATCH employs local optimization for tracing partial sequence-specific assignments within a global, population-based search environment, where the simultaneous application of local and global optimization heuristics guarantees high efficiency and robustness. MATCH thus makes combined use of the two predominant concepts in use for automated NMR assignment of proteins. Dynamic transition and inherent mutation are new techniques that enable automatic adaptation to variable quality of the experimental input data. The concept of dynamic transition is incorporated in all major building blocks of the algorithm, where it enables switching between local and global optimization heuristics at any time during the assignment process. Inherent mutation restricts the intrinsically required randomness of the evolutionary algorithm to those regions of the conformation space that are compatible with the experimental input data. Using intact and artificially deteriorated APSY-NMR input data of proteins, MATCH performed sequence-specific resonance assignment with high efficiency and robustness

Maize, tropical (Zea mays L.).

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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.

Association and linkage analysis of aluminum tolerance genes in maize.

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Allison M Krill

Full Text Available BACKGROUND: Aluminum (Al toxicity is a major worldwide constraint to crop productivity on acidic soils. Al becomes soluble at low pH, inhibiting root growth and severely reducing yields. Maize is an important staple food and commodity crop in acidic soil regions, especially in South America and Africa where these soils are very common. Al exclusion and intracellular tolerance have been suggested as two important mechanisms for Al tolerance in maize, but little is known about the underlying genetics. METHODOLOGY: An association panel of 282 diverse maize inbred lines and three F2 linkage populations with approximately 200 individuals each were used to study genetic variation in this complex trait. Al tolerance was measured as net root growth in nutrient solution under Al stress, which exhibited a wide range of variation between lines. Comparative and physiological genomics-based approaches were used to select 21 candidate genes for evaluation by association analysis. CONCLUSIONS: Six candidate genes had significant results from association analysis, but only four were confirmed by linkage analysis as putatively contributing to Al tolerance: Zea mays AltSB like (ZmASL, Zea mays aluminum-activated malate transporter2 (ALMT2, S-adenosyl-L-homocysteinase (SAHH, and Malic Enzyme (ME. These four candidate genes are high priority subjects for follow-up biochemical and physiological studies on the mechanisms of Al tolerance in maize. Immediately, elite haplotype-specific molecular markers can be developed for these four genes and used for efficient marker-assisted selection of superior alleles in Al tolerance maize breeding programs.

Adsorption, immobilization and activity of cellulase in soil: the impacts of maize straw and its humification

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Ali Akbar Safari Sinegani

2013-12-01

Full Text Available The present work aimed to study some aspects of sorption and immobilization of cellulase molecules on soil components by the analysis of the reactions of cellulase in a soil treated with different levels of maize residue and incubated for 90 days. The analysis of variance showed that the effects of the treatments of maize straw, incubation time and their interaction on cellulase adsorption, desorption and immobilization were statistically significant. The adsorption and immobilization capacities of soil by application of maize straw increased significantly. However they decreased with decreasing the soil organic matter (SOM after 45 days of incubation. The desorption of adsorbed cellulase molecules from the soil by washing with distilled water depended on the SOM contents and its humification. The binding strength of cellulase molecule with fresh miaze straw was significantly stronger than that with humified maize straw. The immobilized cellulase activity, particularly its specific activity increased significantly by increasing the OC contents in the soil treated with maize straw.

Effect of Bambara nut and cowpea intercropped with maize at different times on nutritive quality of maize for ruminant feeding

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Olanite, J. A.

2017-06-01

Full Text Available Effects of Bambara nut and cowpea planted with maize at different times on nutritive quality of maize forage were investigated. The study was laid out in a Completely Randomized Design and the treatments were combination of crop types (Bambara nut-maize (MB and Cowpea-maize (MC and planting times of legumes (2 wks before planting maize, 2WBPM and 2 wks after planting maize, 2WAPM, and sole maize (as control. An experimental field measuring 19 m � 11 m was divided into 3 replicates; each replicate was sub-divided into 5 plots of dimension 3 m2 each, with 1 m and 2 m inter-plots and inter-blocks spacing respectively. Maize forage samples were harvested on each plot at 10 wks after planting, oven-dried, milled and analyzed to evaluate the chemical composition, mineral composition, in vitro gas production and post-incubation characteristics. Results revealed significant differences (P<0.05 among treatments with the highest (95.00% and least DM (92.12% values were recorded for MB 2WBPM and MC 2WAPM, respectively. CP values ranged from 10.36% in MB 2WBPM to 15.67% in MC 2WBPM but not significantly different from 14.19 % recorded for sole maize. Ash ranged from 7.00% in MB 2WAPM to 10.00% in sole maize. MC 2WBPM and sole maize had the highest (50.63% and least (38.40% in ADF content (P<0.05. ADL value (7.25% observed in MB 2WBPM was the highest, compared to the least (5.00% in sole maize. Sole maize recorded the least (40.40% and highest (25.91% cellulose and hemicellulose contents, respectively while MC 2WAPM had the highest (50.88% and lowest (15.80% values for cellulose and hemicellulose, respectively. Ca content (4.55g/kg of MB 2WAPM was lower than the other treatments. P content ranged from 3.54 g/kg in MB 2WAPM to 12.02 g/kg in MC 2WAPM. Gas production rates only varied (P<0.05 at the 3rd, 6th, 24th and 48th hours of incubation. MB 2WBPM yielded highest values of short chain fatty acids (0.09 �mol and metabolizable energy (3.08 MJ/kg while MB

CaMV-35S promoter sequence-specific DNA methylation in lettuce.

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Okumura, Azusa; Shimada, Asahi; Yamasaki, Satoshi; Horino, Takuya; Iwata, Yuji; Koizumi, Nozomu; Nishihara, Masahiro; Mishiba, Kei-ichiro

2016-01-01

We found 35S promoter sequence-specific DNA methylation in lettuce. Additionally, transgenic lettuce plants having a modified 35S promoter lost methylation, suggesting the modified sequence is subjected to the methylation machinery. We previously reported that cauliflower mosaic virus 35S promoter-specific DNA methylation in transgenic gentian (Gentiana triflora × G. scabra) plants occurs irrespective of the copy number and the genomic location of T-DNA, and causes strong gene silencing. To confirm whether 35S-specific methylation can occur in other plant species, transgenic lettuce (Lactuca sativa L.) plants with a single copy of the 35S promoter-driven sGFP gene were produced and analyzed. Among 10 lines of transgenic plants, 3, 4, and 3 lines showed strong, weak, and no expression of sGFP mRNA, respectively. Bisulfite genomic sequencing of the 35S promoter region showed hypermethylation at CpG and CpWpG (where W is A or T) sites in 9 of 10 lines. Gentian-type de novo methylation pattern, consisting of methylated cytosines at CpHpH (where H is A, C, or T) sites, was also observed in the transgenic lettuce lines, suggesting that lettuce and gentian share similar methylation machinery. Four of five transgenic lettuce lines having a single copy of a modified 35S promoter, which was modified in the proposed core target of de novo methylation in gentian, exhibited 35S hypomethylation, indicating that the modified sequence may be the target of the 35S-specific methylation machinery.

Sequence specificity and biological consequences of drugs that bind covalently in the minor groove of DNA

International Nuclear Information System (INIS)

Hurley, L.H.; Needham-VanDevanter, D.R.

1986-01-01

DNA ligands which bind within the minor groove of DNA exhibit varying degrees of sequence selectivity. Factors which contribute to nucleotide sequence recognition by minor groove ligands have been extensively investigated. Electrostatic interactions, ligand and DNA dehydration energies, hydrophobic interactions and steric factors all play significant roles in sequence selectivity in the minor groove. Interestingly, ligand recognition of nucleotide sequence in the minor groove does not involve significant hydrogen bonding. This is in sharp contrast to cellular enzyme and protein recognition of nucleotide sequence, which is achieved in the major groove via specific hydrogen bond formation between individual bases and the ligand. The ability to read nucleotide sequence via hydrogen bonding allows precise binding of proteins to specific DNA sequences. Minor groove ligands examined to date exhibit a much lower sequence specificity, generally binding to a subset of possible sequences, rather than a single sequence. 19 refs., 7 figs

Screening of different insecticides against maize shoot fly atherigona soccata (Rond.) and maize borer. chilo partellus (swinh.)

International Nuclear Information System (INIS)

Shahid, M.A.; Rana, Z.A.; Haq, I.; Tariq, H.

2010-01-01

Field studies were carried out in the research area of the Ayub Agricultural Research Institute, Faisalabad to determine the most effective maize seed treatment against maize shoot fly Atherigona soccata (Rond.) and insecticide against maize borer Chilo partellus (Swinh.) Trials were conducted following RCBD and replicated three times during 2005-2006. Two seed treatments Confider (imidacloprid) 70 WS and pensidor 72% WP (5 and 7 mg/kg seed) along with Confider (imidaclorid) 200 SC at the rate 40 ml/acre in the trial against maize shoot fly whereas, flubendiamide 48%, emamection 1.9 EC, spinosad 240 EC. carbofuran 3 G, indoxacarb 150 SC, alphacypermethrine 20 EC, monomehypo 5 G, bifenthrin 10 EC, cartap 4G, cyhalothrine 2.5 EC, cypermethrin 10 EC at the rate 20 ml, 150 ml, 40 ml, 8 kg, 150 ml, 200 ml, 5 kg, 150 ml, 6 kg. 250 ml and 300 ml per acre against maize borer were treated keeping one plo ast untreated check. Treatments were repeated as borer infestation reached above 5% level. All the seed treatments showed significant control of maize shoot fly in spite of dose 5 or 7 mg/kg seed along with foliar spray of confider 200 SC. The insecticides viz. flubendiamide 48% SC. emamectin 1.9 EC, spinosad 240 EC and carbofuran 3 G. indoxacarb 150 SC. alpha cypermethrin 20 EC, not only responded highest yield 5765, 5294, 5289, 5215, 5168 and 5025 kg/ha respectively but also manage the maize borer below ETL. (author)

A(maize)ing attraction: gravid Anopheles arabiensis are attracted and oviposit in response to maize pollen odours.

Science.gov (United States)

Wondwosen, Betelehem; Hill, Sharon R; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Ignell, Rickard

2017-01-23

Maize cultivation contributes to the prevalence of malaria mosquitoes and exacerbates malaria transmission in sub-Saharan Africa. The pollen from maize serves as an important larval food source for Anopheles mosquitoes, and females that are able to detect breeding sites where maize pollen is abundant may provide their offspring with selective advantages. Anopheles mosquitoes are hypothesized to locate, discriminate among, and select such sites using olfactory cues, and that synthetic volatile blends can mimic these olfactory-guided behaviours. Two-port olfactometer and two-choice oviposition assays were used to assess the attraction and oviposition preference of gravid Anopheles arabiensis to the headspace of the pollen from two maize cultivars (BH-660 and ZM-521). Bioactive compounds were identified using combined gas chromatography and electroantennographic detection from the headspace of the cultivar found to be most attractive (BH-660). Synthetic blends of the volatile compounds were then assessed for attraction and oviposition preference of gravid An. arabiensis, as above. Here the collected headspace volatiles from the pollen of two maize cultivars was shown to differentially attract and stimulate oviposition in gravid An. arabiensis. Furthermore, a five-component synthetic maize pollen odour blend was identified, which elicited the full oviposition behavioural repertoire of the gravid mosquitoes. The cues identified from maize pollen provide important substrates for the development of novel control measures that modulate gravid female behaviour. Such measures are irrespective of indoor or outdoor feeding and resting patterns, thus providing a much-needed addition to the arsenal of tools that currently target indoor biting mosquitoes.

Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

Science.gov (United States)

Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

2002-07-01

Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

Development and validation of an event-specific quantitative PCR method for genetically modified maize MIR162.

Science.gov (United States)

Takabatake, Reona; Masubuchi, Tomoko; Futo, Satoshi; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Teshima, Reiko; Kurashima, Takeyo; Mano, Junichi; Kitta, Kazumi

2014-01-01

A novel real-time PCR-based analytical method was developed for the event-specific quantification of a genetically modified (GM) maize event, MIR162. We first prepared a standard plasmid for MIR162 quantification. The conversion factor (Cf) required to calculate the genetically modified organism (GMO) amount was empirically determined for two real-time PCR instruments, the Applied Biosystems 7900HT (ABI7900) and the Applied Biosystems 7500 (ABI7500) for which the determined Cf values were 0.697 and 0.635, respectively. To validate the developed method, a blind test was carried out in an interlaboratory study. The trueness and precision were evaluated as the bias and reproducibility of relative standard deviation (RSDr). The determined biases were less than 25% and the RSDr values were less than 20% at all evaluated concentrations. These results suggested that the limit of quantitation of the method was 0.5%, and that the developed method would thus be suitable for practical analyses for the detection and quantification of MIR162.

Applying CSM-CERES-Maize to define a sowing window for irrigated maize crop - The Riacho´s Farm case study

Directory of Open Access Journals (Sweden)

Denise Freitas Silva

2011-08-01

Full Text Available Irrigation use constitutes an alternative to improve maize production in Central Minas Gerais State, Brazil. However, even under adequate water supply conditions, other environmental factors may influence maize crop growth and development and may, ultimately, affect grain yield. This study aimed to establish a sowing window for irrigated maize crop, based on simulation results obtained with the decision support model CSM-CERES-Maize. Simulations were made for crop management conditions of Riacho´s Farm, located in Matozinhos, Minas Gerais State, Brazil. It was employed the model´s seasonal tool, along with a data set containing 46 years of weather data records, to simulate maize yield for weekly sowing scenarios, starting on August 1st and ending on July 24th of each year. One defined an irrigated maize sowing window, taking into account the yield break risk that a farmer would be willing to take. The model proved to be an interesting tool to assist in decision making, regarding crop and irrigation management, for an irrigated maize production system. Assuming a 10% yield break in the expected average maximum maize yield, it was defined as sowing window, the period from January 23rd to March 6th, with February 20th as the best sowing date. Other sowing windows may be established according to the risk that the farmer would be willing to take.

Dynamic Maize Responses to Aphid Feeding Are Revealed by a Time Series of Transcriptomic and Metabolomic Assays1[OPEN

Science.gov (United States)

Tzin, Vered; Fernandez-Pozo, Noe; Richter, Annett; Schmelz, Eric A.; Schoettner, Matthias; Schäfer, Martin; Ahern, Kevin R.; Meihls, Lisa N.; Kaur, Harleen; Huffaker, Alisa; Mori, Naoki; Degenhardt, Joerg; Mueller, Lukas A.; Jander, Georg

2015-01-01

As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphid (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with corn leaf aphids for 2 to 96 h. Analysis of infested maize leaves showed two distinct response phases, with the most significant transcriptional and metabolic changes occurring in the first few hours after the initiation of aphid feeding. After 4 d, both gene expression and metabolite profiles of aphid-infested maize reverted to being more similar to those of control plants. Although there was a predominant effect of salicylic acid regulation, gene expression changes also indicated prolonged induction of oxylipins, although not necessarily jasmonic acid, in aphid-infested maize. The role of specific metabolic pathways was confirmed using Dissociator transposon insertions in maize inbred line W22. Mutations in three benzoxazinoid biosynthesis genes, Bx1, Bx2, and Bx6, increased aphid reproduction. In contrast, progeny production was greatly decreased by a transposon insertion in the single W22 homolog of the previously uncharacterized B73 terpene synthases TPS2 and TPS3. Together, these results show that maize leaves shift to implementation of physical and chemical defenses within hours after the initiation of aphid feeding and that the production of specific metabolites can have major effects in maize-aphid interactions. PMID:26378100

Cellular specificity of HIV-1 replication can be controlled by LTR sequences

International Nuclear Information System (INIS)

Reed-Inderbitzin, Edward; Maury, Wendy

2003-01-01

Two well-established determinants of retroviral tropism are envelope sequences that regulate entry and LTR sequences that can regulate viral expression in a cell-specific manner. Studies with human immunodeficiency virus-1 (HIV-1) have demonstrated that tropism of this virus maps primarily to variable envelope sequences. Studies have demonstrated that T cell and macrophage-specific transcription factor binding motifs exist in the upstream region of the LTR U3; however, the ability of the core enhancer/promoter proximal elements (two NF-κB and three Sp1 sites) to function well in macrophages and T cells have led many to conclude that HIV LTR sequences are not primary determinants of HIV tropism. To determine if cellular specificity could be imparted to HIV by the core enhancer elements, the enhancer/promoter proximal region of the HIV LTR was substituted with motifs that control gene expression in a myeloid-specific manner. The enhancer region from equine infectious anemia virus (EIAV) when substituted for the HIV enhancer/promoter proximal region was found to drive expression in a macrophage-specific manner and was responsive to HIV Tat. The addition of a 5' methylation-dependent binding site (MDBP) and a promoter proximal Sp1 motif increased expression without altering cellular specificity. Spacing between the promoter proximal region and the TATA box was also found to influence LTR activity. Infectivity studies using chimeric LTRs within the context of a dual-tropic infectious molecular clone established that these LTRs directed HIV replication and production of infectious virions in macrophages but not primary T cells or T cell lines. This investigation demonstrates that cellular specificity can be imparted onto HIV-1 replication at the level of viral transcription and not entry

Sorghum as an alternative of cultivation to maize; Sorghumhirse als Anbaualternative zum Mais

Energy Technology Data Exchange (ETDEWEB)

Jaekel, Kerstin; Theiss, Markus; Poetzschke, Karen [Saechsisches Landesamt fuer Umwelt, Landwirtschaft und Geologie (LfULG), Dresden (Germany)] [and others

2013-10-01

Due to their high dry matter yield potential Sorghum bicolor and Sorghum bicolor x sudanense are well fitted as feedstock for biogas production. Similar to maize, both species show a high efficiency in their use of water (C4-plants). However, Sorghum has a higher drought tolerance in comparison with maize but is more sensitive to low temperatures. Hence a cultivation of Sorghum is recommendable especially in dry and relatively warm regions, including recultivated areas and even on loess soil, provided that the required temperatures are given. Due to the fact that Sorghum is not affected by the corn root worm, it also could gain relevance in regions were the cultivation of maize is restricted. Furthermore, Sorghum is usable as a catch crop as well as a main crop because of its variable sowing time. Catch crop cultivation, however, yields a significantly lower amount of dry matter and -quality which is a result of its shorter vegetation period. Owing to its higher crude fiber concentration Sorghum achieves a lower theoretically attainable specific methane yield (Weissbach) than maize. Thus only on rare occasions Sorghum does achieve methane yields per hectare that are comparable to maize. Eventually, the competitiveness of Sorghum greatly depends on provision of enhanced cultivars achieved through genetic improvement. (orig.)

Energy productivity and efficiency of maize accounting for the choice of growing season and environmental factors: An empirical analysis from Bangladesh

International Nuclear Information System (INIS)

Rahman, Sanzidur; Rahman, Md. Sayedur

2013-01-01

The paper evaluates sustainability of maize cultivation in Bangladesh in terms of energy use while taking into account factors affecting choice of the growing season and farmers' production environment using a sample selection framework applied to stochastic frontier models. Results reveal that the probability of growing winter maize is influenced positively by gross return, irrigation, subsistence pressure, soil suitability and temperature variability whereas extension contact influences choice negatively. Significant differences exist between winter and summer maize regarding yield, specific energy, net energy balance, energy use efficiency and technical energy efficiency although both systems are highly sustainable and efficient. The energy output from winter maize is 199,585 MJ/ha which is 53.9% higher than the summer maize output of 129,701 MJ/ha. Also, energy input use of winter maize is 110.6% higher than the summer maize. Energy inputs from mechanical power, seeds, fertilizers and organic manures significantly increase energy productivity of winter maize whereas only mechanical power influences summer maize productivity. However, temperature variation and rainfall significantly reduce energy productivity of summer maize. Policy implications include investments in soil conservation and irrigation, development of weather resistant varieties and raising maize price will boost maize cultivation in Bangladesh, a highly sustainable production technology. -- Highlights: ► Maize energy productivity is evaluated subject to season and environmental factors. ► Maize farming for both seasons is highly sustainable in terms of energy use. ► Socio-economic and environmental factors influence choice of growing winter maize. ► Mechanical power, rainfall and temperature influence summer maize productivity. ► Maize farmers of both seasons are highly technically efficient.

The mechanisms of root exudates of maize in improvement of iron nutrition of peanut in peanut/maize intercropping system by 14C tracer technique

International Nuclear Information System (INIS)

Zuo Yuanmei; Chen Qing; Zhang Fusuo

2004-01-01

The related mechanisms of root exudates of maize in improvement iron nutrition of peanut intercropped with maize was investigated by 14 C tracer technique. Neighboring roots between maize and peanut were separated by a 30 μm nylon net, the iron nutrition of peanut was also improved just like normal intercropping of maize and peanut. The results proved that root exudates of maize played an important role in improvement iron nutrition of peanut. The photosynthesis carbohydrate of maize could exuded into the rhizosphere of peanut and transfer into shoot and root of peanut in intercropping system. Root exudates of maize could increased efficiency of iron in soil and improved iron utilization of peanut

Selection for drought tolerance in two tropical maize populations ...

African Journals Online (AJOL)

Drought is a major factor limiting maize (Zea mays L.) yield in much of the world. The need to breed maize cultivars with improved drought tolerance is apparent. This study compared two maize populations, ZM601 and ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant.

Flanking sequence determination and specific PCR identification of transgenic wheat B102-1-2.

Science.gov (United States)

Cao, Jijuan; Xu, Junyi; Zhao, Tongtong; Cao, Dongmei; Huang, Xin; Zhang, Piqiao; Luan, Fengxia

2014-01-01

The exogenous fragment sequence and flanking sequence between the exogenous fragment and recombinant chromosome of transgenic wheat B102-1-2 were successfully acquired using genome walking technology. The newly acquired exogenous fragment encoded the full-length sequence of transformed genes with transformed plasmid and corresponding functional genes including ubi, vector pBANF-bar, vector pUbiGUSPlus, vector HSP, reporter vector pUbiGUSPlus, promoter ubiquitin, and coli DH1. A specific polymerase chain reaction (PCR) identification method for transgenic wheat B102-1-2 was established on the basis of designed primers according to flanking sequence. This established specific PCR strategy was validated by using transgenic wheat, transgenic corn, transgenic soybean, transgenic rice, and non-transgenic wheat. A specifically amplified target band was observed only in transgenic wheat B102-1-2. Therefore, this method is characterized by high specificity, high reproducibility, rapid identification, and excellent accuracy for the identification of transgenic wheat B102-1-2.

Effects of maize planting patterns on the performance of cassava ...

African Journals Online (AJOL)

sola

The design was a split-plot arrangement, laid out in a randomized ... significant differences (P<0.05) between the treatments in the growth and yield parameters of maize. The mean effects of companion crops on maize leaf area were 0.61, 0.60, 0.60 and 0.52 m2/plant for sole maize, maize / melon, maize / cassava and.

Developing Inset Resistant Maize Varieties for Food Security in Kenya

International Nuclear Information System (INIS)

Mugo, S.

2002-01-01

The Insect Resistant Maize for Africa (IRMA) project aims at increasing maize production and food security through development and deployment of stem borer resistant maize germplasm developed using conventional and through biotechnology methods such as Bt maize. Bt maize offers farmers an effective and practical option for controlling stem borers. It was recognized that the development and routine use of Bt maize will require addressing relevant bio-safety, environmental, and community concerns and research and information gathering activities are in place to address these concerns and research and information gathering activities are in place to address these concerns. Suitable Bt gene have been acquired or synthesized and back-crossed into elite maize germplasm at CIMMYT-Mexico, and the effective Cry-proteins against the major maize stem borers in Kenya were identified to better target pests. Stem borer resistant maize germplasm is being developed through conventional breeding, using locally adapted and exotic germplasm. for safe and effective deployment of Bt maize,studies on its impacts on target and non-target arthropods as well as studies on the effects of Bt maize on key non-target arthropods as well as studies on gene flow are underway. Insect resistance management strategies are being developed through quantifying the effectiveness, ???. Socioeconomic impact studies are revealing factors in the society that may influence the adoption of Bt maize in Kenya. Also, baseline data, essential for the monitoring and evaluation of the Bt maize technology in Kenya, has been established. Technology transfer and capacity building, creating awareness and communications have received attention in the project. This paper describes the major research activities as they relate to development of the stem bore resistant maize germplasm

Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding.

Science.gov (United States)

Santiago, Rogelio; Cao, Ana; Butrón, Ana

2015-08-20

Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects.

OPTIMAS-DW: A comprehensive transcriptomics, metabolomics, ionomics, proteomics and phenomics data resource for maize

Directory of Open Access Journals (Sweden)

Colmsee Christian

2012-12-01

Full Text Available Abstract Background Maize is a major crop plant, grown for human and animal nutrition, as well as a renewable resource for bioenergy. When looking at the problems of limited fossil fuels, the growth of the world’s population or the world’s climate change, it is important to find ways to increase the yield and biomass of maize and to study how it reacts to specific abiotic and biotic stress situations. Within the OPTIMAS systems biology project maize plants were grown under a large set of controlled stress conditions, phenotypically characterised and plant material was harvested to analyse the effect of specific environmental conditions or developmental stages. Transcriptomic, metabolomic, ionomic and proteomic parameters were measured from the same plant material allowing the comparison of results across different omics domains. A data warehouse was developed to store experimental data as well as analysis results of the performed experiments. Description The OPTIMAS Data Warehouse (OPTIMAS-DW is a comprehensive data collection for maize and integrates data from different data domains such as transcriptomics, metabolomics, ionomics, proteomics and phenomics. Within the OPTIMAS project, a 44K oligo chip was designed and annotated to describe the functions of the selected unigenes. Several treatment- and plant growth stage experiments were performed and measured data were filled into data templates and imported into the data warehouse by a Java based import tool. A web interface allows users to browse through all stored experiment data in OPTIMAS-DW including all data domains. Furthermore, the user can filter the data to extract information of particular interest. All data can be exported into different file formats for further data analysis and visualisation. The data analysis integrates data from different data domains and enables the user to find answers to different systems biology questions. Finally, maize specific pathway information is

RESPONSIVENESS OF SPATIAL PRICE VOLATILITY TO INCREASED GOVERNMENT PARTICIPATION IN MAIZE GRAIN AND MAIZE MEAL MARKETING IN ZAMBIA

OpenAIRE

Syampaku, E.M; Mafimisebi, Taiwo Ejiola

2014-01-01

The study analyzed the responsiveness of maize grain and maize meal spatial price volatilities to increased government participation in maize grain marketing in Zambia using descriptive statistics and vector auto-regression (VAR). This was achieved by comparing spatial price volatility means and spatial price means for the period under increased government participation with respective means for periods under limited government participation. Also, spatial price volatilities were regressed ag...

Exploring the Bacterial Microbiota of Colombian Fermented Maize Dough “Masa Agria” (Maiz Añejo)

Science.gov (United States)

Chaves-Lopez, Clemencia; Serio, Annalisa; Delgado-Ospina, Johannes; Rossi, Chiara; Grande-Tovar, Carlos D.; Paparella, Antonello

2016-01-01

Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 log CFU/g of presumptive lactic acid bacteria, 5.4 log cfu/g for presumptive acetic bacteria and 5.6 og CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1–3.7) registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella, and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by L. fermentum, L. vaccinostercus, and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favor microbial biodiversity characterized by a useful technological potential. PMID:27524979

Exploring the bacterial microbiota of Colombian fermented maize dough “Masa Agria” (Maiz Añejo

Directory of Open Access Journals (Sweden)

Clemencia Chaves

2016-07-01

Full Text Available Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 Log CFU/g of presumptive lactic acid bacteria (LAB, 5.4 Log cfu/g for presumptive acetic bacteria and 5.6 Log CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1-3.7 registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by Lb. fermentum, Lb. vaccinostercus and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favour microbial biodiversity characterized by a useful technological potential.

Carbaryl residues in maize products

International Nuclear Information System (INIS)

Zayed, S.M.A.D.; Mansour, S.A.; Mostafa, I.Y.; Hassan, A.

1976-01-01

The 14 C-labelled insecticide carbaryl was synthesized from [1- 14 C]-1-naphthol at a specific activity of 3.18mCig -1 . Maize plants were treated with the labelled insecticide under simulated conditions of agricultural practice. Mature plants were harvested and studied for distribution of total residues in untreated grains as popularly roasted and consumed, and in the corn oil and corn germ products. Total residues found under these conditions in the respective products were 0.2, 0.1, 0.45 and 0.16ppm. (author)

A model of a successful utilization of a high genetic potential of maize yield

Directory of Open Access Journals (Sweden)

Pavlov Milovan

2008-01-01

Full Text Available The principle of a system, defined as a ZP system, implying corresponding relationship among research, seed production and seed marketing, is that each segment within the system has its tasks and responsibilities, as well as, a clear interest. This system was established at the Maize Research Institute, Zemun Polje, almost half a century ago. The crucial characteristic is that this system encompasses obtained results of scientific accomplishments (patent - a released hybrid, optimal utilisation of the environmental conditions, facilities for seed drying, processing and packing, staff and transport capacities. The ZP system provides the economic interest of all participants in studies and the maize seed production. The fundamental base of the quality seed production within the ZP system is a multidisciplinary programme on maize breeding, as well as, 535 released hybrids with standard and specific traits. According to regulations in foreign countries, approximately 100 ZP maize hybrids have been released abroad. Agroecological conditions in Serbia are favorable for the development of the best genotypes and the production of basic and certified maize seed. There 10 processing plants that apply recent technologies in the maize seed processing procedure. Several generations of experts have been trained and gained experience within the maize seed production. Three seed testing laboratories have been accredited by the International Seed Testing Association. According to regulations in Serbia, monitoring of seed production under field conditions, and further on, during the processing practice is done only by designate authorities. This study presents one of successful systems of the seed production organization applicable in countries with similar conditions.

Screening for genetically modified organisms sequences in food ...

African Journals Online (AJOL)

We used the Allin 2.0 GMO screening system from Biosmart, Switzerland to screen for the presence of genetically modified food sequences in maize meal samples, fresh fruit and vegetables from some retailers around Gaborone, Botswana. The Allin 2.0 is a multiplex PCR system for the detection of genetically modified ...

Maize (Zea mays L.).

Science.gov (United States)

Frame, Bronwyn; Warnberg, Katey; Main, Marcy; Wang, Kan

2015-01-01

Agrobacterium tumefaciens-mediated transformation is an effective method for introducing genes into maize. In this chapter, we describe a detailed protocol for genetic transformation of the maize genotype Hi II. Our starting plant material is immature embryos cocultivated with an Agrobacterium strain carrying a standard binary vector. In addition to step-by-step laboratory transformation procedures, we include extensive details in growing donor plants and caring for transgenic plants in the greenhouse.

Nutritive value of brewers’ grain and maize silage for fattening rabbits

Directory of Open Access Journals (Sweden)

H. Guermah

2016-09-01

Full Text Available Specific knowledge of the nutritive value of raw materials is fundamental to formulate balanced diets for rabbits and allows greater use of by-products and non-conventional feedstuffs. This paper examines the feeding value of sun-dried brewers’ grain and maize silage (whole plant for fattening rabbits. Twenty-four individually caged 8-wk-old rabbits were used to determine the digestibility. Both wet products were sun-dried and ground before being incorporated into a basal diet. The inclusion level at the expense of all basal ingredients amounted to 30%. Basal diet and both experimental diets were fed ad libitum to 8 rabbits during the 4-d balance trial. The determined digestibility of protein, fat, crude fibre and neutral detergent fibre digestibility amounted to 76.2 and 77.2%; 86.5 and 99.1%; 8.1 and 8.3% and 28.0 and 13.5%, respectively, for brewers’ grain and maize silage. The digestible energy content amounted to 11.66 MJ/kg dry matter (DM (brewers’ grain and 11.10 MJ/kg DM (maize silage. Both by-products have potential as alternative feedstuff in rabbit diets. However, further experiments are necessary to determine the effect of ensilaging the whole maize plant, as a significantly lower (P<0.001 feed intake was observed.

Measuring Maize Seedling Drought Response in Search of Tolerant Germplasm

Directory of Open Access Journals (Sweden)

Dirk Hays

2013-02-01

Full Text Available To identify and develop drought tolerant maize (Zea mays L., high-throughput and cost-effective screening methods are needed. In dicot crops, measuring survival and recovery of seedlings has been successful in predicting drought tolerance but has not been reported in C4 grasses such as maize. Seedlings of sixty-two diverse maize inbred lines and their hybrid testcross progeny were evaluated for germination, survival and recovery after a series of drought cycles. Genotypic differences among inbred lines and hybrid testcrosses were best explained approximately 13 and 18 days after planting, respectively. Genotypic effects were significant and explained over 6% of experimental variance. Specifically three inbred lines had significant survival, and 14 hybrids had significant recovery. However, no significant correlation was observed between hybrids and inbreds (R2 = 0.03, indicating seedling stress response is more useful as a secondary screening parameter in hybrids than in inbred lines per se. Field yield data under full and limited irrigation indicated that seedling drought mechanisms were independent of drought responses at flowering in this study.

Effects Of Agricultural Extension On Cassava And Maize Production ...

African Journals Online (AJOL)

This study was carried out to assess the effects of agricultural extension on food production in Abak Agricultural zone of Akwa Ibom state. Specifically, the effect was measured using the productivity of small-scale maize and cassava farmers between the years 2004 and 2005. Data for the study were collected from 108 ...

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: Adopters, Zea ... Africa, efficient and profitable production of maize is severely constrained by ..... gap by understanding its source. African. Journal of ...

Infectious Maize rayado fino virus from Cloned cDNA.

Science.gov (United States)

Edwards, Michael C; Weiland, John J; Todd, Jane; Stewart, Lucy R

2015-06-01

A full-length cDNA clone was produced from a U.S. isolate of Maize rayado fino virus (MRFV), the type member of the genus Marafivirus within the family Tymoviridae. Infectivity of transcripts derived from cDNA clones was demonstrated by infection of maize plants and protoplasts, as well as by transmission via the known leafhopper vectors Dalbulus maidis and Graminella nigrifrons that transmit the virus in a persistent-propagative manner. Infection of maize plants through vascular puncture inoculation of seed with transcript RNA resulted in the induction of fine stipple stripe symptoms typical of those produced by wild-type MRFV and a frequency of infection comparable with that of the wild type. Northern and Western blotting confirmed the production of MRFV-specific RNAs and proteins in infected plants and protoplasts. An unanticipated increase in subgenomic RNA synthesis over levels in infected plants was observed in protoplasts infected with either wild-type or cloned virus. A conserved cleavage site motif previously demonstrated to function in both Oat blue dwarf virus capsid protein and tymoviral nonstructural protein processing was identified near the amino terminus of the MRFV replicase polyprotein, suggesting that cleavage at this site also may occur.

Integrated analysis of RNA-binding protein complexes using in vitro selection and high-throughput sequencing and sequence specificity landscapes (SEQRS).

Science.gov (United States)

Lou, Tzu-Fang; Weidmann, Chase A; Killingsworth, Jordan; Tanaka Hall, Traci M; Goldstrohm, Aaron C; Campbell, Zachary T

2017-04-15

RNA-binding proteins (RBPs) collaborate to control virtually every aspect of RNA function. Tremendous progress has been made in the area of global assessment of RBP specificity using next-generation sequencing approaches both in vivo and in vitro. Understanding how protein-protein interactions enable precise combinatorial regulation of RNA remains a significant problem. Addressing this challenge requires tools that can quantitatively determine the specificities of both individual proteins and multimeric complexes in an unbiased and comprehensive way. One approach utilizes in vitro selection, high-throughput sequencing, and sequence-specificity landscapes (SEQRS). We outline a SEQRS experiment focused on obtaining the specificity of a multi-protein complex between Drosophila RBPs Pumilio (Pum) and Nanos (Nos). We discuss the necessary controls in this type of experiment and examine how the resulting data can be complemented with structural and cell-based reporter assays. Additionally, SEQRS data can be integrated with functional genomics data to uncover biological function. Finally, we propose extensions of the technique that will enhance our understanding of multi-protein regulatory complexes assembled onto RNA. Copyright © 2016 Elsevier Inc. All rights reserved.

Growth performance and carcass characteristics of Tanzania Shorthorn Zebu cattle finished on molasses or maize grain with rice or maize by-products

DEFF Research Database (Denmark)

Asimwe, I.; Kimambo, A. E.; Laswai, G. H.

2015-01-01

Forty five steers (2.5–3.0 years of age and 200±5 (SEM) kg body weight) were allotted randomly into five diets to assess the effects of finishing Tanzania Shorthorn Zebu (TSZ) cattle in feedlot using diets based on either molasses or maize grain combined with maize or rice by-products. The diets...... were hay and concentrate mixtures of hominy feed with molasses (HFMO), rice polishing with molasses (RPMO), hominy feed with maize meal (HFMM), rice polishing with maize meal (RPMM) and a control of maize meal with molasses (MMMO). All concentrate mixtures contained cotton seed cake, mineral mixture.......35 for HFMO) than in maize grain based diets (6.94, 6.73 and 6.19 for RPMM, MMMO and HFMM, respectively). Energy intake was highest (P

Comparative QTL mapping of resistance to sugarcane mosaic virus in maize based on bioinformatics

Institute of Scientific and Technical Information of China (English)

Xiangling L(U); Xinhai LI; Chuanxiao XIE; Zhuanfang HAO; Hailian JI; Liyu SHI; Shihuang ZHANG

2008-01-01

The development of genomics and bioinfor-matics offers new tools for comparative gene mapping. In this paper, an integrated QTL map for sugarcane mosaic virus (SCMV) resistance in maize was constructed by compiling a total of 81 QTL loci available, using the Genetic Map IBM2 2005 Neighbors as reference. These 81 QTL loci were scattered on 7 chromosomes of maize, and most of them were clustered on chromosomes 3 and 6. By using the method of meta-analysis, we identified one "consensus QTL" on chromosome 3 covering a genetic distance of 6.44 cM, and two on chromosome 6 covering genetic distances of 16 cM and 27.48 cM, respectively. Four positional candidate resistant genes were identified within the "consensus QTL" on chromosome 3 via the strategy of comparative genomics. These results suggest that application of a combination of meta-analysis within a species with sequence homology comparison in a related model plant is an efficient approach to identify the major QTL and its candidate gene(s) for the target traits. The results of this study provide useful information for iden-tifying and cloning the major gene(s) conferring resistance to SCMV in maize.

Templated Chemistry for Sequence-Specific Fluorogenic Detection of Duplex DNA

Science.gov (United States)

Li, Hao; Franzini, Raphael M.; Bruner, Christopher; Kool, Eric T.

2015-01-01

We describe the development of templated fluorogenic chemistry for detection of specific sequences of duplex DNA in solution. In this approach, two modified homopyrimidine oligodeoxynucleotide probes are designed to bind by triple helix formation at adjacent positions on a specific purine-rich target sequence of duplex DNA. One fluorescein-labeled probe contains an α-azidoether linker to a fluorescence quencher; the second (trigger) probe carries a triarylphosphine, designed to reduce the azide and cleave the linker. The data showed that at pH 5.6 these probes yielded a strong fluorescence signal within minutes on addition to a complementary homopurine duplex DNA target. The signal increased by a factor of ca. 60, and was completely dependent on the presence of the target DNA. Replacement of cytosine in the probes with pseudoisocytosine allowed the templated chemistry to proceed readily at pH 7. Single nucleotide mismatches in the target oligonucleotide slowed the templated reaction considerably, demonstrating high sequence selectivity. The use of templated fluorogenic chemistry for detection of duplex DNAs has not been previously reported and may allow detection of double stranded DNA, at least for homopurine-homopyrimidine target sites, under native, non-disturbing conditions. PMID:20859985

Modulation of energy homeostasis in maize and Arabidopsis to develop lines tolerant to drought, genotoxic and oxidative stresses

Directory of Open Access Journals (Sweden)

Elizabeth Njuguna

2018-02-01

Full Text Available Abiotic stresses cause crop losses worldwide that reduce the average yield by more than 50%. Due to the high energy consumed to enhance the respiration rates, the excessive reactive oxygen species release provokes cell death and, ultimately, whole plant decay. A metabolic engineering approach in maize (Zea mays altered the expression of two poly(ADP-ribosylation metabolic pathway proteins, poly(ADP-ribose polymerase (PARP and ADP-ribose-specifIc Nudix hydrolase (NUDX genes that play a role in the maintenance of the energy homeostasis during stresses. By means of RNAi hairpin silencing and CRISPR/Cas9 gene editing strategies, the PARP expression in maize was downregulated or knocked down. The Arabidopsis NUDX7 gene and its two maize homologs, ZmNUDX2 and ZmNUDX8, were overexpressed in maize and Arabidopsis. Novel phenotypes were observed, such as significant tolerance to oxidative stress and improved yield in Arabidopsis and a trend of tolerance to mild drought stress in maize and in Arabidopsis. Key words: poly(ADP-ribose polymerase, Nudix hydrolase, CRISPR/Cas9, maize, oxidative stress, drought stress

Structural, functional and evolutionary characterization of major drought transcription factors families in maize

Science.gov (United States)

Mittal, Shikha; Banduni, Pooja; Mallikarjuna, Mallana G.; Rao, Atmakuri R.; Jain, Prashant A.; Dash, Prasanta K.; Thirunavukkarasu, Nepolean

2018-05-01

Drought is one of the major threats to maize production. In order to improve the production and to breed tolerant hybrids, understanding the genes and regulatory mechanisms during drought stress is important. Transcription factors (TFs) play a major role in gene regulation and many TFs have been identified in response to drought stress. In our experiment, a set of 15 major TF families comprising 1436 genes was structurally and functionally characterized using in-silico tools and a gene expression assay. All 1436 genes were mapped on 10 chromosome of maize. The functional annotation indicated the involvement of these genes in ABA signaling, ROS scavenging, photosynthesis, stomatal regulation, and sucrose metabolism. Duplication was identified as the primary force in divergence and expansion of TF families. Phylogenetic relationship was developed individually for each TF family as well as combined TF families. Phylogenetic analysis grouped the TF family of genes into TF-specific and mixed groups. Phylogenetic analysis of genes belonging to various TF families suggested that the origin of TFs occurred in the lineage of maize evolution. Gene structure analysis revealed that more number of genes were intron-rich as compared to intronless genes. Drought-responsive CRE’s such as ABREA, ABREB, DRE1 and DRECRTCOREAT have been identified. Expression and interaction analyses identified leaf-specific bZIP TF, GRMZM2G140355, as a potential contributor toward drought tolerance in maize. We also analyzed protein-protein interaction network of 269 drought-responsive genes belonging to different drought-related TFs. The information generated on structural and functional characteristics, expression and interaction of the drought-related TF families will be useful to decipher the drought tolerance mechanisms and to derive drought-tolerant genotypes in maize.

CERES-Maize model-based simulation of climate change impacts on maize yields and potential adaptive measures in Heilongjiang Province, China.

Science.gov (United States)

Lin, Yumei; Wu, Wenxiang; Ge, Quansheng

2015-11-01

Climate change would cause negative impacts on future agricultural production and food security. Adaptive measures should be taken to mitigate the adverse effects. The objectives of this study were to simulate the potential effects of climate change on maize yields in Heilongjiang Province and to evaluate two selected typical household-level autonomous adaptive measures (cultivar changes and planting time adjustments) for mitigating the risks of climate change based on the CERES-Maize model. The results showed that flowering duration and maturity duration of maize would be shortened in the future climate and thus maize yield would reduce by 11-46% during 2011-2099 relative to 1981-2010. Increased CO2 concentration would not benefit maize production significantly. However, substituting local cultivars with later-maturing ones and delaying the planting date could increase yields as the climate changes. The results provide insight regarding the likely impacts of climate change on maize yields and the efficacy of selected adaptive measures by presenting evidence-based implications and mitigation strategies for the potential negative impacts of future climate change. © 2014 Society of Chemical Industry.

Compatibility in the Ustilago maydis-maize interaction requires inhibition of host cysteine proteases by the fungal effector Pit2.

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André N Mueller

2013-02-01

Full Text Available The basidiomycete Ustilago maydis causes smut disease in maize, with large plant tumors being formed as the most prominent disease symptoms. During all steps of infection, U. maydis depends on a biotrophic interaction, which requires an efficient suppression of plant immunity. In a previous study, we identified the secreted effector protein Pit2, which is essential for maintenance of biotrophy and induction of tumors. Deletion mutants for pit2 successfully penetrate host cells but elicit various defense responses, which stops further fungal proliferation. We now show that Pit2 functions as an inhibitor of a set of apoplastic maize cysteine proteases, whose activity is directly linked with salicylic-acid-associated plant defenses. Consequently, protease inhibition by Pit2 is required for U. maydis virulence. Sequence comparisons with Pit2 orthologs from related smut fungi identified a conserved sequence motif. Mutation of this sequence caused loss of Pit2 function. Consequently, expression of the mutated protein in U. maydis could not restore virulence of the pit2 deletion mutant, indicating that the protease inhibition by Pit2 is essential for fungal virulence. Moreover, synthetic peptides of the conserved sequence motif showed full activity as protease inhibitor, which identifies this domain as a new, minimal protease inhibitor domain in plant-pathogenic fungi.

Independent introductions and admixtures have contributed to adaptation of European maize and its American counterparts.

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Jean-Tristan Brandenburg

2017-03-01

Full Text Available Through the local selection of landraces, humans have guided the adaptation of crops to a vast range of climatic and ecological conditions. This is particularly true of maize, which was domesticated in a restricted area of Mexico but now displays one of the broadest cultivated ranges worldwide. Here, we sequenced 67 genomes with an average sequencing depth of 18x to document routes of introduction, admixture and selective history of European maize and its American counterparts. To avoid the confounding effects of recent breeding, we targeted germplasm (lines directly derived from landraces. Among our lines, we discovered 22,294,769 SNPs and between 0.9% to 4.1% residual heterozygosity. Using a segmentation method, we identified 6,978 segments of unexpectedly high rate of heterozygosity. These segments point to genes potentially involved in inbreeding depression, and to a lesser extent to the presence of structural variants. Genetic structuring and inferences of historical splits revealed 5 genetic groups and two independent European introductions, with modest bottleneck signatures. Our results further revealed admixtures between distinct sources that have contributed to the establishment of 3 groups at intermediate latitudes in North America and Europe. We combined differentiation- and diversity-based statistics to identify both genes and gene networks displaying strong signals of selection. These include genes/gene networks involved in flowering time, drought and cold tolerance, plant defense and starch properties. Overall, our results provide novel insights into the evolutionary history of European maize and highlight a major role of admixture in environmental adaptation, paralleling recent findings in humans.

Comparative Advantage of Maize- and Grass-Silage Based Feedstock for Biogas Production with Respect to Greenhouse Gas Mitigation

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Andreas Meyer-Aurich

2016-06-01

Full Text Available This paper analyses the comparative advantage of using silage maize or grass as feedstock for anaerobic digestion to biogas from a greenhouse gas (GHG mitigation point of view, taking into account site-specific yield potentials, management options, and land-use change effects. GHG emissions due to the production of biogas were calculated using a life-cycle assessment approach for three different site conditions with specific yield potentials and adjusted management options. While for the use of silage maize, GHG emissions per energy unit were the same for different yield potentials, and the emissions varied substantially for different grassland systems. Without land-use change effects, silage maize-based biogas had lower GHG emissions per energy unit compared to grass-based biogas. Taking land-use change into account, results in a comparative advantage of biogas production from grass-based feedstock produced on arable land compared to silage maize-based feedstock. However, under current frame conditions, it is quite unrealistic that grass production systems would be established on arable land at larger scale.

The effects of improved maize technology on household welfare in Buruku, Benue State, Nigeria

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Victoria I. Audu

2014-12-01

Full Text Available This study was carried out to determine the welfare effects of improved maize technology in Buruku Local Government Area of Benue State, Nigeria. The study also examined the determinants of the adoption of improved maize technology. Structured questionnaires were used in collecting the primary data for the study. A multi-stage random technique was used in selecting 125 farm households for the study. The Logit and ordinary least square (OLS models were used in analyzing the data. The OLS results show that adoption of improved maize varieties is positively and significantly related to household welfare and thus has contributed to moving farm households out of poverty. Other variables found to be statistically significant in explaining household welfare are education, household size, and landholding. The Logit results show that age, household size, off-farm income, and education were found to be significant in influencing farmers’ adoption decisions. Some robustness checks were performed with different specifications of the Logit and OLS models as well as re-estimation with propensity matching score approach. Overall, the results are robust to different specifications.

The cis-regulatory element CCACGTGG is involved in ABA and water-stress responses of the maize gene rab28.

Science.gov (United States)

Pla, M; Vilardell, J; Guiltinan, M J; Marcotte, W R; Niogret, M F; Quatrano, R S; Pagès, M

1993-01-01

The maize gene rab28 has been identified as ABA-inducible in embryos and vegetative tissues. It is also induced by water stress in young leaves. The proximal promoter region contains the conserved cis-acting element CCACGTGG (ABRE) reported for ABA induction in other plant genes. Transient expression assays in rice protoplasts indicate that a 134 bp fragment (-194 to -60 containing the ABRE) fused to a truncated cauliflower mosaic virus promoter (35S) is sufficient to confer ABA-responsiveness upon the GUS reporter gene. Gel retardation experiments indicate that nuclear proteins from tissues in which the rab28 gene is expressed can interact specifically with this 134 bp DNA fragment. Nuclear protein extracts from embryo and water-stressed leaves generate specific complexes of different electrophoretic mobility which are stable in the presence of detergent and high salt. However, by DMS footprinting the same guanine-specific contacts with the ABRE in both the embryo and leaf binding activities were detected. These results indicate that the rab28 promoter sequence CCACGTGG is a functional ABA-responsive element, and suggest that distinct regulatory factors with apparent similar affinity for the ABRE sequence may be involved in the hormone action during embryo development and in vegetative tissues subjected to osmotic stress.

Genome-wide identification of microRNA and siRNA responsive to endophytic beneficial diazotrophic bacteria in maize.

Science.gov (United States)

Thiebaut, Flávia; Rojas, Cristian A; Grativol, Clícia; Motta, Mariana Romeiro; Vieira, Tauan; Regulski, Michael; Martienssen, Robert A; Farinelli, Laurent; Hemerly, Adriana S; Ferreira, Paulo C G

2014-09-06

Small RNA (sRNA) has been described as a regulator of gene expression. In order to understand the role of maize sRNA (Zea mays-hybrid UENF 506-8) during association with endophytic nitrogen-fixing bacteria, we analyzed the sRNA regulated by its association with two diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. Deep sequencing analysis was done with RNA extracted from plants inoculated with H. seropedicae, allowing the identification of miRNA and siRNA. A total of 25 conserved miRNA families and 15 novel miRNAs were identified. A dynamic regulation in response to inoculation was also observed. A hypothetical model involving copper-miRNA is proposed, emphasizing the fact that the up-regulation of miR397, miR398, miR408 and miR528, which is followed by inhibition of their targets, can facilitate association with diazotrophic bacteria. Similar expression patterns were observed in samples inoculated with A. brasilense. Moreover, novel miRNA and siRNA were classified in the Transposable Elements (TE) database, and an enrichment of siRNA aligned with TE was observed in the inoculated samples. In addition, an increase in 24-nt siRNA mapping to genes was observed, which was correlated with an increase in methylation of the coding regions and a subsequent reduction in transcription. Our results show that maize has RNA-based silencing mechanisms that can trigger specific responses when plants interact with beneficial endophytic diazotrophic bacteria. Our findings suggest important roles for sRNA regulation in maize, and probably in other plants, during association with diazotrophic bacteria, emphasizing the up-regulation of Cu-miRNA.

Targeting and tracing of specific DNA sequences with dTALEs in living cells

Science.gov (United States)

Thanisch, Katharina; Schneider, Katrin; Morbitzer, Robert; Solovei, Irina; Lahaye, Thomas; Bultmann, Sebastian; Leonhardt, Heinrich

2014-01-01

Epigenetic regulation of gene expression involves, besides DNA and histone modifications, the relative positioning of DNA sequences within the nucleus. To trace specific DNA sequences in living cells, we used programmable sequence-specific DNA binding of designer transcription activator-like effectors (dTALEs). We designed a recombinant dTALE (msTALE) with variable repeat domains to specifically bind a 19-bp target sequence of major satellite DNA. The msTALE was fused with green fluorescent protein (GFP) and stably expressed in mouse embryonic stem cells. Hybridization with a major satellite probe (3D-fluorescent in situ hybridization) and co-staining for known cellular structures confirmed in vivo binding of the GFP-msTALE to major satellite DNA present at nuclear chromocenters. Dual tracing of major satellite DNA and the replication machinery throughout S-phase showed co-localization during mid to late S-phase, directly demonstrating the late replication timing of major satellite DNA. Fluorescence bleaching experiments indicated a relatively stable but still dynamic binding, with mean residence times in the range of minutes. Fluorescently labeled dTALEs open new perspectives to target and trace DNA sequences and to monitor dynamic changes in subnuclear positioning as well as interactions with functional nuclear structures during cell cycle progression and cellular differentiation. PMID:24371265

Targeting and tracing of specific DNA sequences with dTALEs in living cells.

Science.gov (United States)

Thanisch, Katharina; Schneider, Katrin; Morbitzer, Robert; Solovei, Irina; Lahaye, Thomas; Bultmann, Sebastian; Leonhardt, Heinrich

2014-04-01

Epigenetic regulation of gene expression involves, besides DNA and histone modifications, the relative positioning of DNA sequences within the nucleus. To trace specific DNA sequences in living cells, we used programmable sequence-specific DNA binding of designer transcription activator-like effectors (dTALEs). We designed a recombinant dTALE (msTALE) with variable repeat domains to specifically bind a 19-bp target sequence of major satellite DNA. The msTALE was fused with green fluorescent protein (GFP) and stably expressed in mouse embryonic stem cells. Hybridization with a major satellite probe (3D-fluorescent in situ hybridization) and co-staining for known cellular structures confirmed in vivo binding of the GFP-msTALE to major satellite DNA present at nuclear chromocenters. Dual tracing of major satellite DNA and the replication machinery throughout S-phase showed co-localization during mid to late S-phase, directly demonstrating the late replication timing of major satellite DNA. Fluorescence bleaching experiments indicated a relatively stable but still dynamic binding, with mean residence times in the range of minutes. Fluorescently labeled dTALEs open new perspectives to target and trace DNA sequences and to monitor dynamic changes in subnuclear positioning as well as interactions with functional nuclear structures during cell cycle progression and cellular differentiation.

quixotic coupling between irrigation system and maize-cowpea

African Journals Online (AJOL)

ACSS

number row-1 and maize grain yield, respectively. The ridge ... Key Words: Furrow irrigation, water use efficiency, Zea mays. RÉSUMÉ ... important in arid and semi-arid regions, with ... as maize) canopy is not able to intercept all the solar radiation during the growth period. ... Intercropping maize and legumes considerably ...

Cross-fertilization between genetically modified and non-genetically modified maize crops in Uruguay.

Science.gov (United States)

Galeano, Pablo; Debat, Claudio Martínez; Ruibal, Fabiana; Fraguas, Laura Franco; Galván, Guillermo A

2010-01-01

The cultivation of genetically modified (GM) Bt maize (Zea mays L.) events MON810 and Bt11 is permitted in Uruguay. Local regulations specify that 10% of the crop should be a non-GM cultivar as refuge area for biodiversity, and the distance from other non-GM maize crops should be more than 250 m in order to avoid cross-pollination. However, the degree of cross-fertilization between maize crops in Uruguay is unknown. The level of adventitious presence of GM material in non-GM crops is a relevant issue for organic farming, in situ conservation of genetic resources and seed production. In the research reported here, the occurrence and frequency of cross-fertilization between commercial GM and non-GM maize crops in Uruguay was assessed. The methodology comprised field sampling and detection using DAS-ELISA and PCR. Five field-pair cases where GM maize crops were grown near non-GM maize crops were identified. These cases had the potential to cross-fertilize considering the distance between crops and the similarity of the sowing dates. Adventitious presence of GM material in the offspring of non-GM crops was found in three of the five cases. Adventitious presence of event MON810 or Bt11 in non-GM maize, which were distinguished using specific primers, matched the events in the putative sources of transgenic pollen. Percentages of transgenic seedlings in the offspring of the non-GM crops were estimated as 0.56%, 0.83% and 0.13% for three sampling sites with distances of respectively 40, 100 and 330 m from the GM crops. This is a first indication that adventitious presence of transgenes in non-GM maize crops will occur in Uruguay if isolation by distance and/or time is not provided. These findings contribute to the evaluation of the applicability of the "regulated coexistence policy" in Uruguay. © ISBR, EDP Sciences, 2011.

Biological Control of Fusarium Stalk Rot of Maize Using Bacillus spp

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Joon-Hee Han

2015-12-01

Full Text Available Maize (Zea mays L. is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08 were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

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....

Maize forage aptitude: Combining ability of inbred lines and stability of hybrids

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Luis Máximo Bertoia

2014-12-01

Full Text Available Breeding of forage maize should combine improvement achieved for grain with the specific needs of forage hybrids. Production stability is important when maize is used for silage if the planting area is not in the ideal agronomic environment. The objectives of the present research were: (i to quantify environmental and genetic and their interaction effects on maize silage traits; (ii to identify possible heterotic groups for forage aptitude and suggest the formation of potential heterotic patterns, and (iii to identify suitable inbred line combinations for producing hybrids with forage aptitude. Forty-five hybrids derived from diallelic crosses (without reciprocals among ten inbred lines of maize were evaluated in this study. Combined ANOVA over environments showed differences between genotypes (G, environments (E, and their interactions (GEI. Heritability (H2, and genotypic and phenotypic correlations were estimated to evaluate the variation in and relationships between forage traits. Postdictive and predictive AMMI models were fitted to determine the importance of each source of variation, G, E, and GEI, and to select genotypes simultaneously on yield, quality and stability. A predominance of additive effects was found in the evaluated traits. The heterotic pattern Reid-BSSS × Argentine flint was confirmed for ear yield (EY and harvest index (HI. High and broad genetic variation was found for stover and whole plant traits. Some inbred lines had genes with differential breeding aptitude for ear and stover. Stover and ear yield should be the main breeding objectives in maize forage breeding.

Water transfer in an alfalfa/maize association

International Nuclear Information System (INIS)

Corak, S.J.; Blevins, D.G.; Pallardy, S.G.

1987-01-01

The authors investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the -/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (-/-), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (-*). Predawn leaf water potential of maize in the -/+ treatment fell to -1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near -1.9 megapascals. Leaf water potentials of maize in the -/- and -* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3 H 2 O was injected into the bottom -/+ tube at day 70 or later. Maize in the -/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots

Monitoring of Sesamia nonagrioides resistance to MON 810 maize in the European Union: lessons from a long-term harmonized plan.

Science.gov (United States)

Farinós, Gema P; Hernández-Crespo, Pedro; Ortego, Félix; Castañera, Pedro

2018-03-01

Use of MON 810 maize (Zea mays), which expresses the insecticidal protein Cry1Ab from Bacillus thuringiensis (Bt maize), is a highly effective method to control Sesamia nonagrioides (Lefèbvre), a key maize pest in Mediterranean countries. Monitoring programs to assess the potential development of resistance of target pests to Bt maize are mandatory in the European Union (EU). Here we report the results of the S. nonagrioides resistance monitoring plan implemented for MON 810 maize in the EU between 2004 and 2015 and reassess the different components of this long-term harmonized plan. No major shifts in the susceptibility of S. nonagrioides to the Cry1Ab protein have occurred over time. The reassessment of this long-term program has identified some practical and technical constraints, allowing us to provide specific recommendations for improvement: use reference strains instead of susceptibility baselines as comparators for field-collected populations; shift from dose-response bioassays to diagnostic concentrations; and focus monitoring on areas with high adoption rates, such as the Ebro basin in Spain. There are no signs of field resistance of S. nonagrioides to the Cry1Ab protein of MON 810 maize. Specific recommendations for improvement are provided, based on the knowledge and experience accumulated through the implementation of this unique EU-wide harmonized plan. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Sub-Saharan African maize-based foods

NARCIS (Netherlands)

Ekpa, Onu; Palacios-Rojas, Natalia; Kruseman, Gideon; Fogliano, Vincenzo; Linnemann, Anita R.

2018-01-01

The demand for maize in Sub-Saharan Africa will triple by 2050 due to rapid population growth, while challenges from climate change will threaten agricultural productivity. Most maize breeding programmes have focused on improving agronomic properties and have paid relatively little attention to

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective

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Olga Pechanova

2015-11-01

Full Text Available Maize (Zea mays L. is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective.

Science.gov (United States)

Pechanova, Olga; Pechan, Tibor

2015-11-30

Maize (Zea mays L.) is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

Differential resistance reaction of maize genotypes to maize stem borer (Chilo partellus Swinhoe at Chitwan, Nepal

Directory of Open Access Journals (Sweden)

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.

Whole transcriptome profiling of maize during early somatic embryogenesis reveals altered expression of stress factors and embryogenesis-related genes.

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Stella A G D Salvo

Full Text Available Embryogenic tissue culture systems are utilized in propagation and genetic engineering of crop plants, but applications are limited by genotype-dependent culture response. To date, few genes necessary for embryogenic callus formation have been identified or characterized. The goal of this research was to enhance our understanding of gene expression during maize embryogenic tissue culture initiation. In this study, we highlight the expression of candidate genes that have been previously regarded in the literature as having important roles in somatic embryogenesis. We utilized RNA based sequencing (RNA-seq to characterize the transcriptome of immature embryo explants of the highly embryogenic and regenerable maize genotype A188 at 0, 24, 36, 48, and 72 hours after placement of explants on tissue culture initiation medium. Genes annotated as functioning in stress response, such as glutathione-S-transferases and germin-like proteins, and genes involved with hormone transport, such as PINFORMED, increased in expression over 8-fold in the study. Maize genes with high sequence similarity to genes previously described in the initiation of embryogenic cultures, such as transcription factors BABY BOOM, LEAFY COTYLEDON, and AGAMOUS, and important receptor-like kinases such as SOMATIC EMBRYOGENESIS RECEPTOR LIKE KINASES and CLAVATA, were also expressed in this time course study. By combining results from whole genome transcriptome analysis with an in depth review of key genes that play a role in the onset of embryogenesis, we propose a model of coordinated expression of somatic embryogenesis-related genes, providing an improved understanding of genomic factors involved in the early steps of embryogenic culture initiation in maize and other plant species.

Fungal Diversity of Maize (Zea Mays L. Grains

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Gulbis Kaspars

2016-06-01

Full Text Available Maize is becoming more and more important crop for dairy farming as forage and as substrate for biogas production. The mycotoxin producing fungi can spoil feed, reduce cattle productivity and cause health problems. The aim of this research was to study the mycoflora of maize grains in order to clarify the fungal composition and verify the presence of potential mycotoxin producing fungi. The grain samples were collected from different maize hybrid performance trial in Research and Study farm “Vecauce” of Latvia University of Agriculture in 2014. The fungi from 14 genera were isolated from surface sterilized grains. The most abundant were Alternaria, Fusarium and Penicillium spp. Mycotoxin producing fungi are present in maize grain mycoflora, and there is a risk that maize production can contain mycotoxins.

Maize Bioactive Peptides against Cancer

Science.gov (United States)

Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

2017-06-01

Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

Expression of a truncated ATHB17 protein in maize increases ear weight at silking.

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Elena A Rice

Full Text Available ATHB17 (AT2G01430 is an Arabidopsis gene encoding a member of the α-subclass of the homeodomain leucine zipper class II (HD-Zip II family of transcription factors. The ATHB17 monomer contains four domains common to all class II HD-Zip proteins: a putative repression domain adjacent to a homeodomain, leucine zipper, and carboxy terminal domain. However, it also possesses a unique N-terminus not present in other members of the family. In this study we demonstrate that the unique 73 amino acid N-terminus is involved in regulation of cellular localization of ATHB17. The ATHB17 protein is shown to function as a transcriptional repressor and an EAR-like motif is identified within the putative repression domain of ATHB17. Transformation of maize with an ATHB17 expression construct leads to the expression of ATHB17Δ113, a truncated protein lacking the first 113 amino acids which encodes a significant portion of the repression domain. Because ATHB17Δ113 lacks the repression domain, the protein cannot directly affect the transcription of its target genes. ATHB17Δ113 can homodimerize, form heterodimers with maize endogenous HD-Zip II proteins, and bind to target DNA sequences; thus, ATHB17Δ113 may interfere with HD-Zip II mediated transcriptional activity via a dominant negative mechanism. We provide evidence that maize HD-Zip II proteins function as transcriptional repressors and that ATHB17Δ113 relieves this HD-Zip II mediated transcriptional repression activity. Expression of ATHB17Δ113 in maize leads to increased ear size at silking and, therefore, may enhance sink potential. We hypothesize that this phenotype could be a result of modulation of endogenous HD-Zip II pathways in maize.

Expression of a truncated ATHB17 protein in maize increases ear weight at silking.

Science.gov (United States)

Rice, Elena A; Khandelwal, Abha; Creelman, Robert A; Griffith, Cara; Ahrens, Jeffrey E; Taylor, J Philip; Murphy, Lesley R; Manjunath, Siva; Thompson, Rebecca L; Lingard, Matthew J; Back, Stephanie L; Larue, Huachun; Brayton, Bonnie R; Burek, Amanda J; Tiwari, Shiv; Adam, Luc; Morrell, James A; Caldo, Rico A; Huai, Qing; Kouadio, Jean-Louis K; Kuehn, Rosemarie; Sant, Anagha M; Wingbermuehle, William J; Sala, Rodrigo; Foster, Matt; Kinser, Josh D; Mohanty, Radha; Jiang, Dongming; Ziegler, Todd E; Huang, Mingya G; Kuriakose, Saritha V; Skottke, Kyle; Repetti, Peter P; Reuber, T Lynne; Ruff, Thomas G; Petracek, Marie E; Loida, Paul J

2014-01-01

ATHB17 (AT2G01430) is an Arabidopsis gene encoding a member of the α-subclass of the homeodomain leucine zipper class II (HD-Zip II) family of transcription factors. The ATHB17 monomer contains four domains common to all class II HD-Zip proteins: a putative repression domain adjacent to a homeodomain, leucine zipper, and carboxy terminal domain. However, it also possesses a unique N-terminus not present in other members of the family. In this study we demonstrate that the unique 73 amino acid N-terminus is involved in regulation of cellular localization of ATHB17. The ATHB17 protein is shown to function as a transcriptional repressor and an EAR-like motif is identified within the putative repression domain of ATHB17. Transformation of maize with an ATHB17 expression construct leads to the expression of ATHB17Δ113, a truncated protein lacking the first 113 amino acids which encodes a significant portion of the repression domain. Because ATHB17Δ113 lacks the repression domain, the protein cannot directly affect the transcription of its target genes. ATHB17Δ113 can homodimerize, form heterodimers with maize endogenous HD-Zip II proteins, and bind to target DNA sequences; thus, ATHB17Δ113 may interfere with HD-Zip II mediated transcriptional activity via a dominant negative mechanism. We provide evidence that maize HD-Zip II proteins function as transcriptional repressors and that ATHB17Δ113 relieves this HD-Zip II mediated transcriptional repression activity. Expression of ATHB17Δ113 in maize leads to increased ear size at silking and, therefore, may enhance sink potential. We hypothesize that this phenotype could be a result of modulation of endogenous HD-Zip II pathways in maize.

Expression of a Truncated ATHB17 Protein in Maize Increases Ear Weight at Silking

Science.gov (United States)

Creelman, Robert A.; Griffith, Cara; Ahrens, Jeffrey E.; Taylor, J. Philip; Murphy, Lesley R.; Manjunath, Siva; Thompson, Rebecca L.; Lingard, Matthew J.; Back, Stephanie L.; Larue, Huachun; Brayton, Bonnie R.; Burek, Amanda J.; Tiwari, Shiv; Adam, Luc; Morrell, James A.; Caldo, Rico A.; Huai, Qing; Kouadio, Jean-Louis K.; Kuehn, Rosemarie; Sant, Anagha M.; Wingbermuehle, William J.; Sala, Rodrigo; Foster, Matt; Kinser, Josh D.; Mohanty, Radha; Jiang, Dongming; Ziegler, Todd E.; Huang, Mingya G.; Kuriakose, Saritha V.; Skottke, Kyle; Repetti, Peter P.; Reuber, T. Lynne; Ruff, Thomas G.; Petracek, Marie E.; Loida, Paul J.

2014-01-01

ATHB17 (AT2G01430) is an Arabidopsis gene encoding a member of the α-subclass of the homeodomain leucine zipper class II (HD-Zip II) family of transcription factors. The ATHB17 monomer contains four domains common to all class II HD-Zip proteins: a putative repression domain adjacent to a homeodomain, leucine zipper, and carboxy terminal domain. However, it also possesses a unique N-terminus not present in other members of the family. In this study we demonstrate that the unique 73 amino acid N-terminus is involved in regulation of cellular localization of ATHB17. The ATHB17 protein is shown to function as a transcriptional repressor and an EAR-like motif is identified within the putative repression domain of ATHB17. Transformation of maize with an ATHB17 expression construct leads to the expression of ATHB17Δ113, a truncated protein lacking the first 113 amino acids which encodes a significant portion of the repression domain. Because ATHB17Δ113 lacks the repression domain, the protein cannot directly affect the transcription of its target genes. ATHB17Δ113 can homodimerize, form heterodimers with maize endogenous HD-Zip II proteins, and bind to target DNA sequences; thus, ATHB17Δ113 may interfere with HD-Zip II mediated transcriptional activity via a dominant negative mechanism. We provide evidence that maize HD-Zip II proteins function as transcriptional repressors and that ATHB17Δ113 relieves this HD-Zip II mediated transcriptional repression activity. Expression of ATHB17Δ113 in maize leads to increased ear size at silking and, therefore, may enhance sink potential. We hypothesize that this phenotype could be a result of modulation of endogenous HD-Zip II pathways in maize. PMID:24736658

Effects of INH, DNP, 2, 4-D and CMU on the sugar content of the barley and maize leaves; Efecto de cuatro inhibidores metabolicos (INH, DNP, 2, 3-D y CMU) sobre el contenido en azucares de hohas de cebada (Hordeum vulgare L.) y Maiz (Zea mais L.)

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J; Sancho, P

1979-07-01

1 ppm of the chemicals in nutritive solution was absorbed by barley and maize roots during 24 and 48 hours in dark or light conditioners in order to determine the best conditions. for the obtention of labelled sugars with high specific activity. Results show that the highest specific activity was obtained In maize plants treated with DNP for 24 hours in dark conditions. (Author) 51 refs.

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.

Effect of different seed treatments on maize seed germination parameters under optimal and suboptimal temperature conditions

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Vujošević Bojana

2017-01-01

Full Text Available The aim of this study was to determine the effect of different seed treatments on germination parameters of three maize genotypes under optimal and suboptimal temperature conditions. Seed was treated with recommended doses of three commercial pesticide formulations: metalaxyl-m 10 g/L + fludioxonil 25 g/L, metalaxyl 20 g/kg + prothioconazole 100 g/kg and thiacloprid 400 g/L. Testing was conducted at 25°C and 15°C. Results of the study indicate that there are differences in response of maize genotypes to applied seed treatments, as well as to a specific treatment at optimal and suboptimal temperatures. Some treatments, depending on the mixing partner and temperature conditions, can affect final germination. In other cases, germination rate can be accelerated or prolonged, but with no effect on final germination. In order to provide fast and uniform emergence under different temperature conditions, further examination of the response of maize genotypes to specific seed treatments would be beneficial.

Organism-specific rRNA capture system for application in next-generation sequencing.

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Sai-Kam Li

Full Text Available RNA-sequencing is a powerful tool in studying RNomics. However, the highly abundance of ribosomal RNAs (rRNA and transfer RNA (tRNA have predominated in the sequencing reads, thereby hindering the study of lowly expressed genes. Therefore, rRNA depletion prior to sequencing is often performed in order to preserve the subtle alteration in gene expression especially those at relatively low expression levels. One of the commercially available methods is to use DNA or RNA probes to hybridize to the target RNAs. However, there is always a concern with the non-specific binding and unintended removal of messenger RNA (mRNA when the same set of probes is applied to different organisms. The degree of such unintended mRNA removal varies among organisms due to organism-specific genomic variation. We developed a computer-based method to design probes to deplete rRNA in an organism-specific manner. Based on the computation results, biotinylated-RNA-probes were produced by in vitro transcription and were used to perform rRNA depletion with subtractive hybridization. We demonstrated that the designed probes of 16S rRNAs and 23S rRNAs can efficiently remove rRNAs from Mycobacterium smegmatis. In comparison with a commercial subtractive hybridization-based rRNA removal kit, using organism-specific probes is better in preserving the RNA integrity and abundance. We believe the computer-based design approach can be used as a generic method in preparing RNA of any organisms for next-generation sequencing, particularly for the transcriptome analysis of microbes.

Genomic variation in recently collected maize landraces from Mexico

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María Clara Arteaga

2016-03-01

Full Text Available The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (HE = 0.234 to 0.318 (mean 0.311, while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (HE = 0.262 and 0.234, respectively. The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law. Keywords: Maize, Teosinte, Maize SNP50K BeadChip, Mexican landraces, Proyecto Global de Maíces Nativos

Incomplete dominance of deleterious alleles contributes substantially to trait variation and heterosis in maize.

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Jinliang Yang

2017-09-01

Full Text Available Deleterious alleles have long been proposed to play an important role in patterning phenotypic variation and are central to commonly held ideas explaining the hybrid vigor observed in the offspring of a cross between two inbred parents. We test these ideas using evolutionary measures of sequence conservation to ask whether incorporating information about putatively deleterious alleles can inform genomic selection (GS models and improve phenotypic prediction. We measured a number of agronomic traits in both the inbred parents and hybrids of an elite maize partial diallel population and re-sequenced the parents of the population. Inbred elite maize lines vary for more than 350,000 putatively deleterious sites, but show a lower burden of such sites than a comparable set of traditional landraces. Our modeling reveals widespread evidence for incomplete dominance at these loci, and supports theoretical models that more damaging variants are usually more recessive. We identify haplotype blocks using an identity-by-decent (IBD analysis and perform genomic prediction analyses in which we weigh blocks on the basis of complementation for segregating putatively deleterious variants. Cross-validation results show that incorporating sequence conservation in genomic selection improves prediction accuracy for grain yield and other fitness-related traits as well as heterosis for those traits. Our results provide empirical support for an important role for incomplete dominance of deleterious alleles in explaining heterosis and demonstrate the utility of incorporating functional annotation in phenotypic prediction and plant breeding.

Incomplete dominance of deleterious alleles contributes substantially to trait variation and heterosis in maize.

Science.gov (United States)

Yang, Jinliang; Mezmouk, Sofiane; Baumgarten, Andy; Buckler, Edward S; Guill, Katherine E; McMullen, Michael D; Mumm, Rita H; Ross-Ibarra, Jeffrey

2017-09-01

Deleterious alleles have long been proposed to play an important role in patterning phenotypic variation and are central to commonly held ideas explaining the hybrid vigor observed in the offspring of a cross between two inbred parents. We test these ideas using evolutionary measures of sequence conservation to ask whether incorporating information about putatively deleterious alleles can inform genomic selection (GS) models and improve phenotypic prediction. We measured a number of agronomic traits in both the inbred parents and hybrids of an elite maize partial diallel population and re-sequenced the parents of the population. Inbred elite maize lines vary for more than 350,000 putatively deleterious sites, but show a lower burden of such sites than a comparable set of traditional landraces. Our modeling reveals widespread evidence for incomplete dominance at these loci, and supports theoretical models that more damaging variants are usually more recessive. We identify haplotype blocks using an identity-by-decent (IBD) analysis and perform genomic prediction analyses in which we weigh blocks on the basis of complementation for segregating putatively deleterious variants. Cross-validation results show that incorporating sequence conservation in genomic selection improves prediction accuracy for grain yield and other fitness-related traits as well as heterosis for those traits. Our results provide empirical support for an important role for incomplete dominance of deleterious alleles in explaining heterosis and demonstrate the utility of incorporating functional annotation in phenotypic prediction and plant breeding.

A simple ssr analysis for genetic diversity estimation of maize landraces

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Ignjatovic-Micic Dragana

2015-01-01

Full Text Available collection of 2217 landraces from western Balkan (former Yugoslavia is maintained at Maize Research Institute Zemun Polje gene bank. Nine flint and nine dent accessions from six agro-ecological groups (races, chosen on the basis of diverse pedigrees, were analyzed for genetic relatedness using phenotypic and simple sequence repeat (SSR markers. One of the aims was to establish a reliable set of SSR markers for a rapid diversity analysis using polyacrilamide gels and ethidium bromide staining. In the principal component analysis (PCA the first three principal components accounted for 80.86% of total variation and separated most of the flint from dent landraces. Ten SSR primers revealed a total of 56 and 63 alleles in flint and dent landraces, respectively, with low stuttering and good allele resolution on the gels. High average PIC value (0.822 also supports informativeness and utility of the markers used in this study. Higher genetic variation was observed among flint genotypes, as genetic distances between flint landraces covered a larger range of values (0.11- 0.38 than between dent (0.22 - 0.33 genotypes. Both phenotypic and SSR analyses distinguished flint and dent landraces, but neither of them could abstract agro-ecological groups. The SSR method used gave clear, easy to read band patterns that could be used for reliable allele frequency determination. Genetic diversity revealed for both markers indicated that the landraces were highly adapted to specific environmental conditions and purposes and could be valuable sources of genetic variability. [Projekat Ministarstva nauke Republike Srbije, br. TR31028: Exploitation of maize diversity to improve grain quality and drought tolerance

Increased sequence diversity coverage improves detection of HIV-Specific T cell responses

DEFF Research Database (Denmark)

Frahm, N.; Kaufmann, D.E.; Yusim, K.

2007-01-01

The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss res...

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...

Storage of Maize in Purdue Improved Crop Storage (PICS) Bags.

Science.gov (United States)

Williams, Scott B; Murdock, Larry L; Baributsa, Dieudonne

2017-01-01

Interest in using hermetic technologies as a pest management solution for stored grain has risen in recent years. One hermetic approach, Purdue Improved Crop Storage (PICS) bags, has proven successful in controlling the postharvest pests of cowpea. This success encouraged farmers to use of PICS bags for storing other crops including maize. To assess whether maize can be safely stored in PICS bags without loss of quality, we carried out laboratory studies of maize grain infested with Sitophilus zeamais (Motshulsky) and stored in PICS triple bags or in woven polypropylene bags. Over an eight month observation period, temperatures in the bags correlated with ambient temperature for all treatments. Relative humidity inside PICS bags remained constant over this period despite the large changes that occurred in the surrounding environment. Relative humidity in the woven bags followed ambient humidity closely. PICS bags containing S. zeamais-infested grain saw a significant decline in oxygen compared to the other treatments. Grain moisture content declined in woven bags, but remained high in PICS bags. Seed germination was not significantly affected over the first six months in all treatments, but declined after eight months of storage when infested grain was held in woven bags. Relative damage was low across treatments and not significantly different between treatments. Overall, maize showed no signs of deterioration in PICS bags versus the woven bags and PICS bags were superior to woven bags in terms of specific metrics of grain quality.

Carbon Dioxide Mediates the Response to Temperature and Water Activity Levels in Aspergillus flavus during Infection of Maize Kernels

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Matthew K. Gilbert

2017-12-01

Full Text Available Aspergillus flavus is a saprophytic fungus that may colonize several important crops, including cotton, maize, peanuts and tree nuts. Concomitant with A. flavus colonization is its potential to secrete mycotoxins, of which the most prominent is aflatoxin. Temperature, water activity (aw and carbon dioxide (CO2 are three environmental factors shown to influence the fungus-plant interaction, which are predicted to undergo significant changes in the next century. In this study, we used RNA sequencing to better understand the transcriptomic response of the fungus to aw, temperature, and elevated CO2 levels. We demonstrate that aflatoxin (AFB1 production on maize grain was altered by water availability, temperature and CO2. RNA-Sequencing data indicated that several genes, and in particular those involved in the biosynthesis of secondary metabolites, exhibit different responses to water availability or temperature stress depending on the atmospheric CO2 content. Other gene categories affected by CO2 levels alone (350 ppm vs. 1000 ppm at 30 °C/0.99 aw, included amino acid metabolism and folate biosynthesis. Finally, we identified two gene networks significantly influenced by changes in CO2 levels that contain several genes related to cellular replication and transcription. These results demonstrate that changes in atmospheric CO2 under climate change scenarios greatly influences the response of A. flavus to water and temperature when colonizing maize grain.

Chromatin accessibility data sets show bias due to sequence specificity of the DNase I enzyme.

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Hashem Koohy

Full Text Available DNase I is an enzyme which cuts duplex DNA at a rate that depends strongly upon its chromatin environment. In combination with high-throughput sequencing (HTS technology, it can be used to infer genome-wide landscapes of open chromatin regions. Using this technology, systematic identification of hundreds of thousands of DNase I hypersensitive sites (DHS per cell type has been possible, and this in turn has helped to precisely delineate genomic regulatory compartments. However, to date there has been relatively little investigation into possible biases affecting this data.We report a significant degree of sequence preference spanning sites cut by DNase I in a number of published data sets. The two major protocols in current use each show a different pattern, but for a given protocol the pattern of sequence specificity seems to be quite consistent. The patterns are substantially different from biases seen in other types of HTS data sets, and in some cases the most constrained position lies outside the sequenced fragment, implying that this constraint must relate to the digestion process rather than events occurring during library preparation or sequencing.DNase I is a sequence-specific enzyme, with a specificity that may depend on experimental conditions. This sequence specificity is not taken into account by existing pipelines for identifying open chromatin regions. Care must be taken when interpreting DNase I results, especially when looking at the precise locations of the reads. Future studies may be able to improve the sensitivity and precision of chromatin state measurement by compensating for sequence bias.

The hydrophobic core of twin-arginine signal sequences orchestrates specific binding to Tat-pathway related chaperones.

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Anitha Shanmugham

Full Text Available Redox enzyme maturation proteins (REMPs bind pre-proteins destined for translocation across the bacterial cytoplasmic membrane via the twin-arginine translocation system and enable the enzymatic incorporation of complex cofactors. Most REMPs recognize one specific pre-protein. The recognition site usually resides in the N-terminal signal sequence. REMP binding protects signal peptides against degradation by proteases. REMPs are also believed to prevent binding of immature pre-proteins to the translocon. The main aim of this work was to better understand the interaction between REMPs and substrate signal sequences. Two REMPs were investigated: DmsD (specific for dimethylsulfoxide reductase, DmsA and TorD (specific for trimethylamine N-oxide reductase, TorA. Green fluorescent protein (GFP was genetically fused behind the signal sequences of TorA and DmsA. This ensures native behavior of the respective signal sequence and excludes any effects mediated by the mature domain of the pre-protein. Surface plasmon resonance analysis revealed that these chimeric pre-proteins specifically bind to the cognate REMP. Furthermore, the region of the signal sequence that is responsible for specific binding to the corresponding REMP was identified by creating region-swapped chimeric signal sequences, containing parts of both the TorA and DmsA signal sequences. Surprisingly, specificity is not encoded in the highly variable positively charged N-terminal region of the signal sequence, but in the more similar hydrophobic C-terminal parts. Interestingly, binding of DmsD to its model substrate reduced membrane binding of the pre-protein. This property could link REMP-signal peptide binding to its reported proofreading function.

Maize production in mid hills of Nepal: from food to feed security

OpenAIRE

Krishna Prasad Timsina; Yuga Nath Ghimire; Jeevan Lamichhane

2016-01-01

This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize productio...

Vulnerability of Maize Yields to Droughts in Uganda

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Terence Epule Epule

2017-03-01

Full Text Available Climate projections in Sub-Saharan Africa (SSA forecast an increase in the intensity and frequency of droughts with implications for maize production. While studies have examined how maize might be affected at the continental level, there have been few national or sub-national studies of vulnerability. We develop a vulnerability index that combines sensitivity, exposure and adaptive capacity and that integrates agroecological, climatic and socio-economic variables to evaluate the national and spatial pattern of maize yield vulnerability to droughts in Uganda. The results show that maize yields in the north of Uganda are more vulnerable to droughts than in the south and nationally. Adaptive capacity is higher in the south of the country than in the north. Maize yields also record higher levels of sensitivity and exposure in the north of Uganda than in the south. Latitudinally, it is observed that maize yields in Uganda tend to record higher levels of vulnerability, exposure and sensitivity towards higher latitudes, while in contrast, the adaptive capacity of maize yields is higher towards the lower latitudes. In addition to lower precipitation levels in the north of the country, these observations can also be explained by poor soil quality in most of the north and socio-economic proxies, such as, higher poverty and lower literacy rates in the north of Uganda.

Rhythmic diel pattern of gene expression in juvenile maize leaf.

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Maciej Jończyk

Full Text Available BACKGROUND: Numerous biochemical and physiological parameters of living organisms follow a circadian rhythm. Although such rhythmic behavior is particularly pronounced in plants, which are strictly dependent on the daily photoperiod, data on the molecular aspects of the diurnal cycle in plants is scarce and mostly concerns the model species Arabidopsis thaliana. Here we studied the leaf transcriptome in seedlings of maize, an important C4 crop only distantly related to A. thaliana, throughout a cycle of 10 h darkness and 14 h light to look for rhythmic patterns of gene expression. RESULTS: Using DNA microarrays comprising ca. 43,000 maize-specific probes we found that ca. 12% of all genes showed clear-cut diel rhythms of expression. Cluster analysis identified 35 groups containing from four to ca. 1,000 genes, each comprising genes of similar expression patterns. Perhaps unexpectedly, the most pronounced and most common (concerning the highest number of genes expression maxima were observed towards and during the dark phase. Using Gene Ontology classification several meaningful functional associations were found among genes showing similar diel expression patterns, including massive induction of expression of genes related to gene expression, translation, protein modification and folding at dusk and night. Additionally, we found a clear-cut tendency among genes belonging to individual clusters to share defined transcription factor-binding sequences. CONCLUSIONS: Co-expressed genes belonging to individual clusters are likely to be regulated by common mechanisms. The nocturnal phase of the diurnal cycle involves gross induction of fundamental biochemical processes and should be studied more thoroughly than was appreciated in most earlier physiological studies. Although some general mechanisms responsible for the diel regulation of gene expression might be shared among plants, details of the diurnal regulation of gene expression seem to differ

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

In vitro utilization of amylopectin and high-amylose maize (Amylomaize) starch granules by human colonic bacteria.

Science.gov (United States)

Wang, X; Conway, P L; Brown, I L; Evans, A J

1999-11-01

It has been well established that a certain amount of ingested starch can escape digestion in the human small intestine and consequently enters the large intestine, where it may serve as a carbon source for bacterial fermentation. Thirty-eight types of human colonic bacteria were screened for their capacity to utilize soluble starch, gelatinized amylopectin maize starch, and high-amylose maize starch granules by measuring the clear zones on starch agar plates. The six cultures which produced clear zones on amylopectin maize starch- containing plates were selected for further studies for utilization of amylopectin maize starch and high-amylose maize starch granules A (amylose; Sigma) and B (Culture Pro 958N). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to detect bacterial starch-degrading enzymes. It was demonstrated that Bifidobacterium spp., Bacteroides spp., Fusobacterium spp., and strains of Eubacterium, Clostridium, Streptococcus, and Propionibacterium could hydrolyze the gelatinized amylopectin maize starch, while only Bifidobacterium spp. and Clostridium butyricum could efficiently utilize high-amylose maize starch granules. In fact, C. butyricum and Bifidobacterium spp. had higher specific growth rates in the autoclaved medium containing high-amylose maize starch granules and hydrolyzed 80 and 40% of the amylose, respectively. Starch-degrading enzymes were cell bound on Bifidobacterium and Bacteroides cells and were extracellular for C. butyricum. Active staining for starch-degrading enzymes on SDS-PAGE gels showed that the Bifidobacterium cells produced several starch-degrading enzymes with high relative molecular (M(r)) weights (>160,000), medium-sized relative molecular weights (>66,000), and low relative molecular weights (spp. and C. butyricum degraded and utilized granules of amylomaize starch.

The Mechanisms of Maize Resistance to Fusarium verticillioides by comprehensive analysis of RNA-seq Data

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Yanping Wang

2016-11-01

Full Text Available Fusarium verticillioides is the most commonly reported fungal species responsible for ear rot of maize which substantially reduces grain yield. It also results in a substantial accumulation of mycotoxins that give rise to toxic response when ingested by animals and humans. For inefficient control by chemical and agronomic measures, it thus becomes more desirable to select more resistant varieties. However, the molecular mechanisms underlying the infection process remain poorly understood, which hampers the application of quantitative resistance in breeding programs. Here, we reveal the disease-resistance mechanism of the maize inbred line of BT-1 which displays high resistance to ear rot using RNA high throughput sequencing. By analyzing RNA-seq data from the BT-1 kernels before and after F. verticillioides inoculation, we found that transcript levels of genes associated with key pathways are dramatically changed compared with the control treatment. Differential gene expression in ear rot resistant and susceptible maize was confirmed by RNA microarray and qRT-PCR analyses. Further investigation suggests that the small heat shock protein family, some secondary metabolites, and the signaling pathways of abscisic acid (ABA, jasmonic acid (JA or salicylic acids (SA may be involved in the pathogen-associated molecular pattern-triggered immunity against F. verticillioides. These data will not only provide new insights into the molecular resistant mechanisms against fungi invading, but may also result in the identification of key molecular factors associated with ear rot resistance in maize.

Effect of simultaneously induced environmental stimuli on electrical signalling and gas exchange in maize plants.

Science.gov (United States)

Vuralhan-Eckert, Jasmin; Lautner, Silke; Fromm, Jörg

2018-04-01

Electrical signalling in response to environmental stimuli is a well-known phenomenon in higher plants. For example, in maize, different stimuli, such as wounding or re-irrigation after drought, incite characteristic electrical signals which have quite particular effects on gas exchange. What is less well understood is how plants (specifically maize) respond when two different environmental stimuli are applied simultaneously. To explore this, a three-stage experiment was designed. In the first stage, drought conditions were simulated by decreasing the soil water content to 30-40 % of field capacity. In these conditions, and in contrast to well-watered plants, the maize exhibited only 60-70% of the original level of stomatal conductance and 50-60 % of the original photosynthesis rate. In the second stage of the experiment the plants were re-irrigated and heat stimulated separately. Re-irrigation led to specific electrical signals followed by a gradual increase of gas exchange. In contrast, after heat stimulation of a leaf an electrical signal was evoked that reduced the net CO 2 -uptake rate as well as stomatal conductance. In the third stage, to elucidate how plants process simultaneous re-irrigation and heat stimulation, the drought-stressed maize plants were re-watered and heat-stimulated at the same time. Results showed a two phase response. In the first phase there was a rapid decrease in both the CO 2 uptake rate and the stomatal conductance, while in the second phase each of these parameters increased gradually. Thus, the results strongly support the view that the responses from both stimuli were combined, indicating that maize plants can process simultaneously applied stimuli. Copyright © 2018 Elsevier GmbH. All rights reserved.

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.

Social limitations of maize farmers' adaptation to neoliberal policy reform in Mexico

NARCIS (Netherlands)

Groenewald, S.F.; Niehof, A.

2015-01-01

This article highlights the interfaces between micro-level livelihoods, social networks, and macroeconomic trends and policies. Specifically, it analyzes the role of farmer groups in livelihood adaptation of smallholder maize producers in southern Mexico. We show how neoliberal market changes have

Intercropping maize with cassava or cowpea in Ghana | Ennin ...

African Journals Online (AJOL)

Maize/cassava and maize/cowpea intercrops were evaluated in southern Ghana, over a 5-year period to determine the optimum combination of component crop varieties and component plant population densities to optimize productivity of maize-based intercropping systems. Results indicated that some cowpea varieties ...

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...

Systemic virus-induced gene silencing allows functional characterization of maize genes during biotrophic interaction with Ustilago maydis.

Science.gov (United States)

van der Linde, Karina; Kastner, Christine; Kumlehn, Jochen; Kahmann, Regine; Doehlemann, Gunther

2011-01-01

Infection of maize (Zea mays) plants with the corn smut fungus Ustilago maydis leads to the formation of large tumors on the stem, leaves and inflorescences. In this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed massive and stage-specific changes in host gene expression during disease progression. To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a virus-induced gene silencing (VIGS) system based on the brome mosaic virus (BMV) for maize. Conditions were established that allowed successful U. maydis infection of BMV-preinfected maize plants. This set-up enabled quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (qRT-PCR)-based readout. In proof-of-principle experiments, an U. maydis-induced terpene synthase was shown to negatively regulate disease development while a protein involved in cell death inhibition was required for full virulence of U. maydis. The results suggest that this system is a versatile tool for the rapid identification of maize genes that determine compatibility with U. maydis. © (2010) Max Planck Society. Journal compilation © New Phytologist Trust (2010).

Inter- and intraspecific variation in leaf economic traits in wheat and maize.

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Martin, Adam R; Hale, Christine E; Cerabolini, Bruno E L; Cornelissen, Johannes H C; Craine, Joseph; Gough, William A; Kattge, Jens; Tirona, Cairan K F

2018-02-01

Leaf Economics Spectrum (LES) trait variation underpins multiple agroecological processes and many prominent crop yield models. While there are numerous independent studies assessing trait variation in crops, to date there have been no comprehensive assessments of intraspecific trait variation (ITV) in LES traits for wheat and maize: the world's most widespread crops. Using trait databases and peer-reviewed literature, we compiled over 700 records of specific leaf area (SLA), maximum photosynthetic rates ( A max ) and leaf nitrogen (N) concentrations, for wheat and maize. We evaluated intraspecific LES trait variation, and intraspecific trait-environment relationships. While wheat and maize occupy the upper 90th percentile of LES trait values observed across a global species pool, ITV ranged widely across the LES in wheat and maize. Fertilization treatments had strong impacts on leaf N, while plant developmental stage (here standardized as the number of days since planting) had strong impacts on A max ; days since planting, N fertilization and irrigation all influenced SLA. When controlling for these factors, intraspecific responses to temperature and precipitation explained 39.4 and 43.7 % of the variation in A max and SLA, respectively, but only 5.4 % of the variation in leaf N. Despite a long history of domestication in these species, ITV in wheat and maize among and within cultivars remains large. Intraspecific trait variation is a critical consideration to refine regional to global models of agroecosystem structure, function and food security. Considerable opportunities and benefits exist for consolidating a crop trait database for a wider range of domesticated plant species.

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense

Science.gov (United States)

Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J.; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

Metabolic profiling of two maize (Zea mays L. inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

Directory of Open Access Journals (Sweden)

Liziane Cristina Brusamarello-Santos

Full Text Available Maize roots can be colonized by free-living atmospheric nitrogen (N2-fixing bacteria (diazotrophs. However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2, already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+. The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts

Metabolic profiling of two maize (Zea mays L.) inbred lines inoculated with the nitrogen fixing plant-interacting bacteria Herbaspirillum seropedicae and Azospirillum brasilense.

Science.gov (United States)

Brusamarello-Santos, Liziane Cristina; Gilard, Françoise; Brulé, Lenaïg; Quilleré, Isabelle; Gourion, Benjamin; Ratet, Pascal; Maltempi de Souza, Emanuel; Lea, Peter J; Hirel, Bertrand

2017-01-01

Maize roots can be colonized by free-living atmospheric nitrogen (N2)-fixing bacteria (diazotrophs). However, the agronomic potential of non-symbiotic N2-fixation in such an economically important species as maize, has still not been fully exploited. A preliminary approach to improve our understanding of the mechanisms controlling the establishment of such N2-fixing associations has been developed, using two maize inbred lines exhibiting different physiological characteristics. The bacterial-plant interaction has been characterized by means of a metabolomic approach. Two established model strains of Nif+ diazotrophic bacteria, Herbaspirillum seropedicae and Azospirillum brasilense and their Nif- couterparts defficient in nitrogenase activity, were used to evaluate the impact of the bacterial inoculation and of N2 fixation on the root and leaf metabolic profiles. The two N2-fixing bacteria have been used to inoculate two genetically distant maize lines (FV252 and FV2), already characterized for their contrasting physiological properties. Using a well-controlled gnotobiotic experimental system that allows inoculation of maize plants with the two diazotrophs in a N-free medium, we demonstrated that both maize lines were efficiently colonized by the two bacterial species. We also showed that in the early stages of plant development, both bacterial strains were able to reduce acetylene, suggesting that they contain functional nitrogenase activity and are able to efficiently fix atmospheric N2 (Fix+). The metabolomic approach allowed the identification of metabolites in the two maize lines that were representative of the N2 fixing plant-bacterial interaction, these included mannitol and to a lesser extend trehalose and isocitrate. Whilst other metabolites such as asparagine, although only exhibiting a small increase in maize roots following bacterial infection, were specific for the two Fix+ bacterial strains, in comparison to their Fix- counterparts. Moreover, a number

Identification of Bacillus anthracis specific chromosomal sequences by suppressive subtractive hybridization

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Redkar Rajendra

2004-02-01

Full Text Available Abstract Background Bacillus anthracis, Bacillus thuringiensis and Bacillus cereus are closely related members of the B. cereus-group of bacilli. Suppressive subtractive hybridization (SSH was used to identify specific chromosomal sequences unique to B. anthracis. Results Two SSH libraries were generated. Genomic DNA from plasmid-cured B. anthracis was used as the tester DNA in both libraries, while genomic DNA from either B. cereus or B. thuringiensis served as the driver DNA. Progressive screening of the libraries by colony filter and Southern blot analyses identified 29 different clones that were specific for the B. anthracis chromosome relative not only to the respective driver DNAs, but also to seven other different strains of B. cereus and B. thuringiensis included in the process. The nucleotide sequences of the clones were compared with those found in genomic databases, revealing that over half of the clones were located into 2 regions on the B. anthracis chromosome. Conclusions Genes encoding potential cell wall synthesis proteins dominated one region, while bacteriophage-related sequences dominated the other region. The latter supports the hypothesis that acquisition of these bacteriophage sequences occurred during or after speciation of B. anthracis relative to B. cereus and B. thuringiensis. This study provides insight into the chromosomal differences between B. anthracis and its closest phylogenetic relatives.

A novel beta-glucosidase from the cell wall of maize (Zea mays L.): rapid purification and partial characterization

Science.gov (United States)

Nematollahi, W. P.; Roux, S. J.

1999-01-01

Plants have a variety of glycosidic conjugates of hormones, defense compounds, and other molecules that are hydrolyzed by beta-glucosidases (beta-D-glucoside glucohydrolases, E.C. 3.2.1.21). Workers have reported several beta-glucosidases from maize (Zea mays L.; Poaceae), but have localized them mostly by indirect means. We have purified and partly characterized a 58-Ku beta-glucosidase from maize, which we conclude from a partial sequence analysis, from kinetic data, and from its localization is not identical to any of those already reported. A monoclonal antibody, mWP 19, binds this enzyme, and localizes it in the cell walls of maize coleoptiles. An earlier report showed that mWP19 inhibits peroxidase activity in crude cell wall extracts and can immunoprecipitate peroxidase activity from these extracts, yet purified preparations of the 58 Ku protein had little or no peroxidase activity. The level of sequence similarity between beta-glucosidases and peroxidases makes it unlikely that these enzymes share epitopes in common. Contrary to a previous conclusion, these results suggest that the enzyme recognized by mWP19 is not a peroxidase, but there is a wall peroxidase closely associated with the 58 Ku beta-glucosidase in crude preparations. Other workers also have co-purified distinct proteins with beta-glucosidases. We found no significant charge in the level of immunodetectable beta-glucosidase in mesocotyls or coleoptiles that precedes the red light-induced changes in the growth rate of these tissues.

Maize production in mid hills of Nepal: from food to feed security

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Krishna Prasad Timsina

2016-12-01

Full Text Available This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize production. The results revealed that 60%, 25% and 3% of the grain were used for animal feed, food and seed respectively in hill districts. Whereas the remaining amount of the maize (12% was sold to the different buyers. The proportion of maize feed supply to different animals in the study area was varying. Result shows that at least 1.5 million tons of maize is required only to the feed industries affiliated with national feed industry association in Nepal. Similarly, out of total maize used in feed production, 87% of the maize was imported from India each year by feed industries. Analysis shows negative correlation between scale of feed production and use of domestic maize due to unavailability of required quantity of maize in time. The major pre-condition of feed industries for maize buying was moisture content which must be equal or less than 14%. Very little or no inert materials and physical injury, free from fungal attack and bigger size were also the criteria for maize buying. However, some of the feed industries were also thinking about protein and amino acid contents. Result shows 13% and 8.5% increasing demand of poultry feed and animal feed, respectively over the last five year in Nepal. Most likely, maize is known as a means of food security in Nepal, however, in the context of changing utilization patterns at the farm level and also tremendous increasing demand of maize at the industry level suggest to give more focus on development and dissemination of

A model-based approach to preplanting risk assessment for gray leaf spot of maize.

Science.gov (United States)

Paul, P A; Munkvold, G P

2004-12-01

ABSTRACT Risk assessment models for gray leaf spot of maize, caused by Cercospora zeae-maydis, were developed using preplanting site and maize genotype data as predictors. Disease severity at the dough/dent plant growth stage was categorized into classes and used as the response variable. Logistic regression and classification and regression tree (CART) modeling approaches were used to predict severity classes as a function of planting date (PD), amount of maize soil surface residue (SR), cropping sequence, genotype maturity and gray leaf spot resistance (GLSR) ratings, and longitude (LON). Models were development using 332 cases collected between 1998 and 2001. Thirty cases collected in 2002 were used to validate the models. Preplanting data showed a strong relationship with late-season gray leaf spot severity classes. The most important predictors were SR, PD, GLSR, and LON. Logistic regression models correctly classified 60 to 70% of the validation cases, whereas the CART models correctly classified 57 to 77% of these cases. Cases misclassified by the CART models were mostly due to overestimation, whereas the logistic regression models tended to misclassify cases by underestimation. Both the CART and logistic regression models have potential as management decision-making tools. Early quantitative assessment of gray leaf spot risk would allow for more sound management decisions being made when warranted.

Maize flour fortification in Africa: markets, feasibility, coverage, and costs.

Science.gov (United States)

Fiedler, John L; Afidra, Ronald; Mugambi, Gladys; Tehinse, John; Kabaghe, Gladys; Zulu, Rodah; Lividini, Keith; Smitz, Marc-Francois; Jallier, Vincent; Guyondet, Christophe; Bermudez, Odilia

2014-04-01

The economic feasibility of maize flour and maize meal fortification in Kenya, Uganda, and Zambia is assessed using information about the maize milling industry, households' purchases and consumption levels of maize flour, and the incremental cost and estimated price impacts of fortification. Premix costs comprise the overwhelming share of incremental fortification costs and vary by 50% in Kenya and by more than 100% across the three countries. The estimated incremental cost of maize flour fortification per metric ton varies from $3.19 in Zambia to $4.41 in Uganda. Assuming all incremental costs are passed onto the consumer, fortification in Zambia would result in at most a 0.9% increase in the price of maize flour, and would increase annual outlays of the average maize flour-consuming household by 0.2%. The increases for Kenyans and Ugandans would be even less. Although the coverage of maize flour fortification is not likely to be as high as some advocates have predicted, fortification is economically feasible, and would reduce deficiencies of multiple micronutrients, which are significant public health problems in each of these countries. © 2013 New York Academy of Sciences.

Mixture design of rice flour, maize starch and wheat starch for optimization of gluten free bread quality.

Science.gov (United States)

Mancebo, Camino M; Merino, Cristina; Martínez, Mario M; Gómez, Manuel

2015-10-01

Gluten-free bread production requires gluten-free flours or starches. Rice flour and maize starch are two of the most commonly used raw materials. Over recent years, gluten-free wheat starch is available on the market. The aim of this research was to optimize mixtures of rice flour, maize starch and wheat starch using an experimental mixture design. For this purpose, dough rheology and its fermentation behaviour were studied. Quality bread parameters such as specific volume, texture, cell structure, colour and acceptability were also analysed. Generally, starch incorporation reduced G* and increased the bread specific volume and cell density, but the breads obtained were paler than the rice flour breads. Comparing the starches, wheat starch breads had better overall acceptability and had a greater volume than maize-starch bread. The highest value for sensorial acceptability corresponded to the bread produced with a mixture of rice flour (59 g/100 g) and wheat starch (41 g/100 g).

Flanking sequence determination and event-specific detection of genetically modified wheat B73-6-1.

Science.gov (United States)

Xu, Junyi; Cao, Jijuan; Cao, Dongmei; Zhao, Tongtong; Huang, Xin; Zhang, Piqiao; Luan, Fengxia

2013-05-01

In order to establish a specific identification method for genetically modified (GM) wheat, exogenous insert DNA and flanking sequence between exogenous fragment and recombinant chromosome of GM wheat B73-6-1 were successfully acquired by means of conventional polymerase chain reaction (PCR) and thermal asymmetric interlaced (TAIL)-PCR strategies. Newly acquired exogenous fragment covered the full-length sequence of transformed genes such as transformed plasmid and corresponding functional genes including marker uidA, herbicide-resistant bar, ubiquitin promoter, and high-molecular-weight gluten subunit. The flanking sequence between insert DNA revealed high similarity with Triticum turgidum A gene (GenBank: AY494981.1). A specific PCR detection method for GM wheat B73-6-1 was established on the basis of primers designed according to the flanking sequence. This specific PCR method was validated by GM wheat, GM corn, GM soybean, GM rice, and non-GM wheat. The specifically amplified target band was observed only in GM wheat B73-6-1. This method is of high specificity, high reproducibility, rapid identification, and excellent accuracy for the identification of GM wheat B73-6-1.

Detection of the 35S promoter in transgenic maize via various isothermal amplification techniques: a practical approach.

Science.gov (United States)

Zahradnik, Celine; Kolm, Claudia; Martzy, Roland; Mach, Robert L; Krska, Rudolf; Farnleitner, Andreas H; Brunner, Kurt

2014-11-01

In 2003 the European Commission introduced a 0.9% threshold for food and feed products containing genetically modified organism (GMO)-derived components. For commodities containing GMO contents higher than this threshold, labelling is mandatory. To provide a DNA-based rapid and simple detection method suitable for high-throughput screening of GMOs, several isothermal amplification approaches for the 35S promoter were tested: strand displacement amplification, nicking-enzyme amplification reaction, rolling circle amplification, loop-mediated isothermal amplification (LAMP) and helicase-dependent amplification (HDA). The assays developed were tested for specificity in order to distinguish between samples containing genetically modified (GM) maize and non-GM maize. For those assays capable of this discrimination, tests were performed to determine the lower limit of detection. A false-negative rate was determined to rule out whether GMO-positive samples were incorrectly classified as GMO-negative. A robustness test was performed to show reliable detection independent from the instrument used for amplification. The analysis of three GM maize lines showed that only LAMP and HDA were able to differentiate between the GMOs MON810, NK603, and Bt11 and non-GM maize. Furthermore, with the HDA assay it was possible to realize a detection limit as low as 0.5%. A false-negative rate of only 5% for 1% GM maize for all three maize lines shows that HDA has the potential to be used as an alternative strategy for the detection of transgenic maize. All results obtained with the LAMP and HDA assays were compared with the results obtained with a previously reported real-time PCR assay for the 35S promoter in transgenic maize. This study presents two new screening assays for detection of the 35S promoter in transgenic maize by applying the isothermal amplification approaches HDA and LAMP.

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.

Structural basis for sequence-specific recognition of DNA by TAL effectors

KAUST Repository

Deng, Dong; Yan, Chuangye; Pan, Xiaojing; Mahfouz, Magdy M.; Wang, Jiawei; Zhu, Jiankang; Shi, Yi Gong; Yan, Nieng

2012-01-01

TAL (transcription activator-like) effectors, secreted by phytopathogenic bacteria, recognize host DNA sequences through a central domain of tandem repeats. Each repeat comprises 33 to 35 conserved amino acids and targets a specific base pair

Analysis of B Cell Repertoire Dynamics Following Hepatitis B Vaccination in Humans, and Enrichment of Vaccine-specific Antibody Sequences.

Science.gov (United States)

Galson, Jacob D; Trück, Johannes; Fowler, Anna; Clutterbuck, Elizabeth A; Münz, Márton; Cerundolo, Vincenzo; Reinhard, Claudia; van der Most, Robbert; Pollard, Andrew J; Lunter, Gerton; Kelly, Dominic F

2015-12-01

Generating a diverse B cell immunoglobulin repertoire is essential for protection against infection. The repertoire in humans can now be comprehensively measured by high-throughput sequencing. Using hepatitis B vaccination as a model, we determined how the total immunoglobulin sequence repertoire changes following antigen exposure in humans, and compared this to sequences from vaccine-specific sorted cells. Clonal sequence expansions were seen 7 days after vaccination, which correlated with vaccine-specific plasma cell numbers. These expansions caused an increase in mutation, and a decrease in diversity and complementarity-determining region 3 sequence length in the repertoire. We also saw an increase in sequence convergence between participants 14 and 21 days after vaccination, coinciding with an increase of vaccine-specific memory cells. These features allowed development of a model for in silico enrichment of vaccine-specific sequences from the total repertoire. Identifying antigen-specific sequences from total repertoire data could aid our understanding B cell driven immunity, and be used for disease diagnostics and vaccine evaluation.

MaizeGDB: enabling access to basic, translational, and applied research information

Science.gov (United States)

MaizeGDB is the Maize Genetics and Genomics Database (available online at http://www.maizegdb.org). The MaizeGDB project is not simply an online database and website but rather an information service to maize researchers that supports customized data access and analysis needs to individual research...

"Omics" of maize stress response for sustainable food production: opportunities and challenges.

Science.gov (United States)

Gong, Fangping; Yang, Le; Tai, Fuju; Hu, Xiuli; Wang, Wei

2014-12-01

Maize originated in the highlands of Mexico approximately 8700 years ago and is one of the most commonly grown cereal crops worldwide, followed by wheat and rice. Abiotic stresses (primarily drought, salinity, and high and low temperatures), together with biotic stresses (primarily fungi, viruses, and pests), negatively affect maize growth, development, and eventually production. To understand the response of maize to abiotic and biotic stresses and its mechanism of stress tolerance, high-throughput omics approaches have been used in maize stress studies. Integrated omics approaches are crucial for dissecting the temporal and spatial system-level changes that occur in maize under various stresses. In this comprehensive analysis, we review the primary types of stresses that threaten sustainable maize production; underscore the recent advances in maize stress omics, especially proteomics; and discuss the opportunities, challenges, and future directions of maize stress omics, with a view to sustainable food production. The knowledge gained from studying maize stress omics is instrumental for improving maize to cope with various stresses and to meet the food demands of the exponentially growing global population. Omics systems science offers actionable potential solutions for sustainable food production, and we present maize as a notable case study.

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

Maize and the Malnutrition Conundrum in South Africa | BOOYENS ...

African Journals Online (AJOL)

In this paper, the author gives an overview of the factors leading to maize becoming a staple food among black people in South Africa. The purported relationship between maize consumption and malnutrition, proposals as well as experimental and practical efforts to correct the dietary deficiencies of maize are briefly ...

The effect of frequency-specific sound signals on the germination of maize seeds.

Science.gov (United States)

Vicient, Carlos M

2017-07-25

The effects of sound treatments on the germination of maize seeds were determined. White noise and bass sounds (300 Hz) had a positive effect on the germination rate. Only 3 h treatment produced an increase of about 8%, and 5 h increased germination in about 10%. Fast-green staining shows that at least part of the effects of sound are due to a physical alteration in the integrity of the pericarp, increasing the porosity of the pericarp and facilitating oxygen availability and water and oxygen uptake. Accordingly, by removing the pericarp from the seeds the positive effect of the sound on the germination disappeared.

Specific versus non-specific immune responses in an invertebrate species evidenced by a comparative de novo sequencing study.

Directory of Open Access Journals (Sweden)

Emeline Deleury

Full Text Available Our present understanding of the functioning and evolutionary history of invertebrate innate immunity derives mostly from studies on a few model species belonging to ecdysozoa. In particular, the characterization of signaling pathways dedicated to specific responses towards fungi and Gram-positive or Gram-negative bacteria in Drosophila melanogaster challenged our original view of a non-specific immunity in invertebrates. However, much remains to be elucidated from lophotrochozoan species. To investigate the global specificity of the immune response in the fresh-water snail Biomphalaria glabrata, we used massive Illumina sequencing of 5'-end cDNAs to compare expression profiles after challenge by Gram-positive or Gram-negative bacteria or after a yeast challenge. 5'-end cDNA sequencing of the libraries yielded over 12 millions high quality reads. To link these short reads to expressed genes, we prepared a reference transcriptomic database through automatic assembly and annotation of the 758,510 redundant sequences (ESTs, mRNAs of B. glabrata available in public databases. Computational analysis of Illumina reads followed by multivariate analyses allowed identification of 1685 candidate transcripts differentially expressed after an immune challenge, with a two fold ratio between transcripts showing a challenge-specific expression versus a lower or non-specific differential expression. Differential expression has been validated using quantitative PCR for a subset of randomly selected candidates. Predicted functions of annotated candidates (approx. 700 unisequences belonged to a large extend to similar functional categories or protein types. This work significantly expands upon previous gene discovery and expression studies on B. glabrata and suggests that responses to various pathogens may involve similar immune processes or signaling pathways but different genes belonging to multigenic families. These results raise the question of the importance

Chromosome-specific sequencing reveals an extensive dispensable genome component in wheat

Czech Academy of Sciences Publication Activity Database

Liu, M.; Stiller, J.; Holušová, Kateřina; Vrána, Jan; Liu, D.; Doležel, Jaroslav; Liu, C.

2016-01-01

Roč. 6, NOV 8 (2016), č. článku 36398. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GBP501/12/G090 Institutional support: RVO:61389030 Keywords : triticum-aestivum l. * fusarium crown rot * pan-genome * hexaploid wheat * bread wheat * draft genome * rna-seq * maize * transcriptome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.259, year: 2016

Review: Maize research and production in Nigeria | Iken | African ...

African Journals Online (AJOL)

Maize (Zea mays) is a major important cereal being cultivated in the rainforest and the derived Savannah zones of Nigeria. Land races, improved high yielding and pest and diseases resistant varieties of maize have been developed. Key words: Maize, Zea mays, Nigeria. African Journal of Biotechnology Vol.3(6) 2004: 302- ...

Making better maize plants for sustainable grain production in a changing climate.

Science.gov (United States)

Gong, Fangping; Wu, Xiaolin; Zhang, Huiyong; Chen, Yanhui; Wang, Wei

2015-01-01

Achieving grain supply security with limited arable land is a major challenge in the twenty-first century, owing to the changing climate and increasing global population. Maize plays an increasingly vital role in global grain production. As a C4 plant, maize has a high yield potential. Maize is predicted to become the number one cereal in the world by 2020. However, maize production has plateaued in many countries, and hybrid and production technologies have been fully exploited. Thus, there is an urgent need to shape maize traits and architectures for increased stress tolerance and higher yield in a changing climate. Recent achievements in genomics, proteomics, and metabolomics have provided an unprecedented opportunity to make better maize. In this paper, we discuss the current challenges and potential of maize production, particularly in China. We also highlight the need for enhancing maize tolerance to drought and heat waves, summarize the elite shoot and root traits and phenotypes, and propose an ideotype for sustainable maize production in a changing climate. This will facilitate targeted maize improvement through a conventional breeding program combined with molecular techniques.

The Combining Ability of Maize Inbred Lines for Grain Yield and ...

African Journals Online (AJOL)

The Combining Ability of Maize Inbred Lines for Grain Yield and Reaction to Grey ... East African Journal of Sciences ... (GLS) to maize production, the national maize research program of Ethiopia ... The information from this study will be useful for the development of high-yielding and GLS disease-resistant maize varieties.

Sequence motifs in MADS transcription factors responsible for specificity and diversification of protein-protein interaction.

Directory of Open Access Journals (Sweden)

Aalt D J van Dijk

Full Text Available Protein sequences encompass tertiary structures and contain information about specific molecular interactions, which in turn determine biological functions of proteins. Knowledge about how protein sequences define interaction specificity is largely missing, in particular for paralogous protein families with high sequence similarity, such as the plant MADS domain transcription factor family. In comparison to the situation in mammalian species, this important family of transcription regulators has expanded enormously in plant species and contains over 100 members in the model plant species Arabidopsis thaliana. Here, we provide insight into the mechanisms that determine protein-protein interaction specificity for the Arabidopsis MADS domain transcription factor family, using an integrated computational and experimental approach. Plant MADS proteins have highly similar amino acid sequences, but their dimerization patterns vary substantially. Our computational analysis uncovered small sequence regions that explain observed differences in dimerization patterns with reasonable accuracy. Furthermore, we show the usefulness of the method for prediction of MADS domain transcription factor interaction networks in other plant species. Introduction of mutations in the predicted interaction motifs demonstrated that single amino acid mutations can have a large effect and lead to loss or gain of specific interactions. In addition, various performed bioinformatics analyses shed light on the way evolution has shaped MADS domain transcription factor interaction specificity. Identified protein-protein interaction motifs appeared to be strongly conserved among orthologs, indicating their evolutionary importance. We also provide evidence that mutations in these motifs can be a source for sub- or neo-functionalization. The analyses presented here take us a step forward in understanding protein-protein interactions and the interplay between protein sequences and

Agrobacterium tumefaciens-MEDIATED IN-PLANTA TRANSFORMATION OF INDONESIAN MAIZE USING pIG121Hm-Cs PLASMID CONTAINING nptII AND hpt GENES

Directory of Open Access Journals (Sweden)

Edy Listanto

2017-05-01

Full Text Available Maize (Zea mays L. productivity in Indonesia is challenged to be increased using genetic engineering. Recent advances in Agrobacterium tumefaciens-mediated in-planta transforma-tion makes it possible to transform maize with low cost, and simple method. This study aimed to confirm pIG121Hm-Cs plasmid in A. tumefaciens, and to estimate the efficiency level of  A. tumefaciens-mediated in-planta transformation of Indonesian maize by using pIG121Hm-Cs plasmid containing nptII and hpt genes. A series of studies were conducted including confirmation of gene construct of pIG121Hm-Cs plasmid in A. tumefaciens, transformation of four maize lines through A. tumefaciens-mediated in-planta technique, acclimatization of transformant plants and molecular analysis of selected plants using polymerase chain reaction (PCR. The pIG121Hm-Cs plasmid was confirmed via PCR analysis using specific primers of nptII and hpt genes and resulted 700 bp and 500 bp for fragments of nptII and hpt, respectively. After selection, acclimatization and molecular analysis steps, the efficiency levels of transformation of four maize lines were low, ranging from 3.8% to 12.8%. The level of transformation efficiency of ST-27 line was the highest accounting for 12.8% of 45 planted embryos on selection medium based on PCR analysis using specific primer for nptII gene. Overall, A. tumefaciens-mediated in planta transformation on maize floral pistil in this study proved to be successful and rapid. Therefore, this enhanced transformation method will be beneficial for Indonesian maize genetic engineering.

Field-evolved resistance to Cry1Ab maize by Spodoptera frugiperda in Brazil.

Science.gov (United States)

Omoto, Celso; Bernardi, Oderlei; Salmeron, Eloisa; Sorgatto, Rodrigo J; Dourado, Patrick M; Crivellari, Augusto; Carvalho, Renato A; Willse, Alan; Martinelli, Samuel; Head, Graham P

2016-09-01

The first Bt maize in Brazil was launched in 2008 and contained the MON 810 event, which expresses Cry1Ab protein. Although the Cry1Ab dose in MON 810 is not high against fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), MON 810 provided commercial levels of control. To support insect resistance management in Brazil, the baseline and ongoing susceptibility of FAW was examined using protein bioassays, and the level of control and life history parameters of FAW were evaluated on MON 810 maize. Baseline diet overlay assays with Cry1Ab (16 µg cm(-2) ) caused 76.3% mortality to field FAW populations sampled in 2009. Moderate mortality (48.8%) and significant growth inhibition (88.4%) were verified in leaf-disc bioassays. In greenhouse trials, MON 810 had significantly less damage than non-Bt maize. The surviving FAW larvae on MON 810 (22.4%) had a 5.5 day increase in life cycle time and a 24% reduction in population growth rate. Resistance monitoring (2010-2015) showed a significant reduction in Cry1Ab susceptibility of FAW over time. Additionally, a significant reduction in the field efficacy of MON 810 maize against FAW was observed in different regions from crop season 2009 to 2013. The decrease in susceptibility to Cry1Ab was expected, but the specific contributions to this resistance by MON 810 maize cannot be distinguished from cross-resistance to Cry1Ab caused by exposure to Cry1F maize. Technologies combining multiple novel insecticidal traits with no cross-resistance to the current Cry1 proteins and high activity against the same target pests should be pursued in Brazil and similar environments. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Extraction and characterization of natural cellulose fibers from maize tassel

CSIR Research Space (South Africa)

Maepa, CE

2015-04-01

Full Text Available This article reports on the extraction and characterization of novel natural cellulose fibers obtained from the maize (tassel) plant. Cellulose was extracted from the agricultural residue (waste biomaterial) of maize tassel. The maize tassel fibers...

Usage of γ-ray treatment for productivity increasing of maize

International Nuclear Information System (INIS)

Ilieva, V.; Dimov, K.

2003-01-01

The aim of this study is to determine the influence of γ irradiation on phosphorus nutrition and maize productivity increasing. The vegetation experiment with irradiated and non-irradiated maize seeds in controlled conditions (moisture and temperature) for determination of phosphorus and phosphorus-gypsum absorption was carried out. The influence of γ irradiation on maize growth, export of mineral elements in maize, phosphorus fertilizing and dry biomass of maize plants are presented. The effect of the moisture of γ irradiated maize seeds (sort 'Knezha' - 3L - 621) on dry substance and yield of green mass is also discussed. Based on the presented experimental data the following conclusion have been made: the maize seeds (sort 'Knezha, hybrid H-708) simulation is useful; in all variants of phosphorus-gypsum absorption the increasing of plant mass yield (absolutely dry) is observed; the absorbed phosphates reserve is enhanced twice; the efficiency of 32 P use in stimulated seeds is higher than in non-stimulated seeds; the phosphorus content in maize (sort 'Knezha' - 2L - 611) is increasing mainly in leaves after X-ray irradiation (750 - 1500 R); γ irradiation (7.5 Gy) stimulate the root system (18%) and side roots development and drying up overcome

Biofuel, land and water: maize, switchgrass or Miscanthus?

International Nuclear Information System (INIS)

Zhuang Qianlai; Qin Zhangcai; Chen Min

2013-01-01

The productive cellulosic crops switchgrass and Miscanthus are considered as viable biofuel sources. To meet the 2022 national biofuel target mandate, actions must be taken, e.g., maize cultivation must be intensified and expanded, and other biofuel crops (switchgrass and Miscanthus) must be cultivated. This raises questions on the use efficiencies of land and water; to date, the demand on these resources to meet the national biofuel target has rarely been analyzed. Here, we present a data-model assimilation analysis, assuming that maize, switchgrass and Miscanthus will be grown on currently available croplands in the US. Model simulations suggest that maize can produce 3.0–5.4 kiloliters (kl) of ethanol for every hectare of land, depending on the feedstock to ethanol conversion efficiency; Miscanthus has more than twice the biofuel production capacity relative to maize, and switchgrass is the least productive of the three potential sources of ethanol. To meet the biofuel target, about 26.5 million hectares of land and over 90 km 3 of water (of evapotranspiration) are needed if maize grain alone is used. If Miscanthus was substituted for maize, the process would save half of the land and one third of the water. With more advanced biofuel conversion technology for Miscanthus, only nine million hectares of land and 45 km 3 of water would probably meet the national target. Miscanthus could be a good alternative biofuel crop to maize due to its significantly lower demand for land and water on a per unit of ethanol basis. (letter)

Assimilate unloading from maize (Zea mays L.) pedicel tissues

International Nuclear Information System (INIS)

Porter, G.A.; Knievel, D.P.; Shannon, J.C.

1987-01-01

Sugar and 14 C-assimilate release from the pedicel tissue of attached maize (Zea mays L.) kernels was studied following treatment with solute concentrations of up to 800 millimolal. Exposure and collection times ranged from 3 to 6 hours. Sugar and 14 C-assimilate unloading and collection in agar traps was reduced by 25 and 43%, respectively, following exposure to 800 millimolal mannitol. Inhibition of unloading was not specific to mannitol, since similar concentrations of glucose, fructose, or equimolar glucose plus fructose resulted in comparable inhibition. Ethylene glycol, a rapidly permeating solute which should not greatly influence cell turgor, did not inhibit 14 C-assimilate unloading. Based on these results, they suggest that inhibition of unloading by high concentrations of sugar or mannitol was due to reduced pedicel cell turgor. Changes in pedicel cell turgor may play a role in the regulation of assimilate transfer within the maize kernel

P1 epigenetic regulation in leaves of high altitude maize landraces: effect of UV-B radiation

Directory of Open Access Journals (Sweden)

Sebastian Pablo Rius

2016-04-01

Full Text Available P1 is a R2R3-MYB transcription factor that regulates the accumulation of a specific group of flavonoids in maize floral tissues, such as flavones and phlobaphenes. P1 is also highly expressed in leaves of maize landraces adapted to high altitudes and higher levels of UV-B radiation. In this work, we analyzed the epigenetic regulation of the P1 gene by UV-B in leaves of different maize landraces. Our results demonstrate that DNA methylation in the P1 proximal promoter, intron1 and intron2 is decreased by UV-B in all lines analyzed; however, the basal DNA methylation levels are lower in the landraces than in B73, a low altitude inbred line. DNA demethylation by UV-B is accompanied by a decrease in H3 methylation at Lys 9 and 27, and by an increase in H3 acetylation. smRNAs complementary to specific regions of the proximal promoter and of intron 2 3' end are also decreased by UV-B; interestingly, P1 smRNA levels are lower in the landraces than in B73 both under control conditions and after UV-B exposure, suggesting that smRNAs regulate P1 expression by UV-B in maize leaves. Finally, we investigated if different P1 targets in flower tissues are also regulated by this transcription factor in response to UV-B. Some targets analyzed show an induction in maize landraces in response to UV-B, with higher basal expression levels in the landraces than in B73; however, not all the transcripts analyzed were found to be regulated by UV-B in leaves.

14C-incorporation into sugars and organic acids of water-stressed maize leaves

International Nuclear Information System (INIS)

Becker, T.; Fock, H.

1986-01-01

The incorporation of 14 C into sugars and some organic acids of maize leaves has been studied in relation to the leaf water potential by feeding 14 CO 2 (370 ppm) for 1,2 and 4 min during steady state photosynthesis at 25 0 C (PAR = 800 μmol m -2 s -1 ). The relative specific radioactivity (RSA) of the sugars was low (0.2% after 4 min) at -0.62 MPa (control) and decreased by about 50% when psi dropped to -0.95 MPa. The authors conclude that the low rate of photosynthetic sugar synthesis in maize leaves decreased during water stress. The RSA of malate was extremely low at -0.62 MPa (0.02%). This result may be the consequence of the large pool size of malate in maize leaves. The authors presume that there are two malate pools present in maize leaves, a small metabolic pool and a larger storage pool. The RSA of malate decreased during the stress period. This is consistent with the decline in net CO 2 uptake during water stress. The pool sizes of citrate and isocitrate increased when psi dropped to -0.95 MPa. As practically no radioactivity was detected in these organic acids, they conclude that these compounds are synthesized from unlabelled precursors during water stress

Production of high-amylose maize lines using RNA interference in ...

African Journals Online (AJOL)

amylose maize lines with a low T-DNA copy number, demonstrating that RNAi is an efficient method for the production of high-amylose maize lines. Key words: Maize, high-amylose, RNA interference, starch branching enzyme gene sbe2a.

Development of an event-specific hydrolysis probe quantitative real-time polymerase chain reaction assay for Embrapa 5.1 genetically modified common bean (Phaseolus vulgaris).

Science.gov (United States)

Treml, Diana; Venturelli, Gustavo L; Brod, Fábio C A; Faria, Josias C; Arisi, Ana C M

2014-12-10

A genetically modified (GM) common bean event, namely Embrapa 5.1, resistant to the bean golden mosaic virus (BGMV), was approved for commercialization in Brazil. Brazilian regulation for genetically modified organism (GMO) labeling requires that any food containing more than 1% GMO be labeled. The event-specific polymerase chain reaction (PCR) method has been the primary trend for GMO identification and quantitation because of its high specificity based on the flanking sequence. This work reports the development of an event-specific assay, named FGM, for Embrapa 5.1 detection and quantitation by use of SYBR Green or hydrolysis probe. The FGM assay specificity was tested for Embrapa 2.3 event (a noncommercial GM common bean also resistant to BGMV), 46 non-GM common bean varieties, and other crop species including maize, GM maize, soybean, and GM soybean. The FGM assay showed high specificity to detect the Embrapa 5.1 event. Standard curves for the FGM assay presented a mean efficiency of 95% and a limit of detection (LOD) of 100 genome copies in the presence of background DNA. The primers and probe developed are suitable for the detection and quantitation of Embrapa 5.1.

A survey of the sequence-specific interaction of damaging agents with DNA: emphasis on antitumor agents.

Science.gov (United States)

Murray, V

1999-01-01

This article reviews the literature concerning the sequence specificity of DNA-damaging agents. DNA-damaging agents are widely used in cancer chemotherapy. It is important to understand fully the determinants of DNA sequence specificity so that more effective DNA-damaging agents can be developed as antitumor drugs. There are five main methods of DNA sequence specificity analysis: cleavage of end-labeled fragments, linear amplification with Taq DNA polymerase, ligation-mediated polymerase chain reaction (PCR), single-strand ligation PCR, and footprinting. The DNA sequence specificity in purified DNA and in intact mammalian cells is reviewed for several classes of DNA-damaging agent. These include agents that form covalent adducts with DNA, free radical generators, topoisomerase inhibitors, intercalators and minor groove binders, enzymes, and electromagnetic radiation. The main sites of adduct formation are at the N-7 of guanine in the major groove of DNA and the N-3 of adenine in the minor groove, whereas free radical generators abstract hydrogen from the deoxyribose sugar and topoisomerase inhibitors cause enzyme-DNA cross-links to form. Several issues involved in the determination of the DNA sequence specificity are discussed. The future directions of the field, with respect to cancer chemotherapy, are also examined.

Iron and manganese oxides modified maize straw to remove tylosin from aqueous solutions.

Science.gov (United States)

Yin, Yongyuan; Guo, Xuetao; Peng, Dan

2018-08-01

Maize straw modified by iron and manganese oxides was synthesized via a simple and environmentally friendly method. Three maize straw materials, the original maize straw, maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides, were detected by SEM, BET, XPS, XRD and FTIR. The results showed that maize straw was successfully modified and maize straw modified by iron and manganese oxides has a larger surface area than MS. According to the experimental data, the sorption trend could conform to the pseudo-second-order kinetic model well, and the sorption ability of tylosin on sorbents followed the order of original maize straw oxides iron and manganese oxides. The study indicated that manganese oxides and iron-manganese oxides could significantly enhance the sorption capacity of original maize straw. The sorption isotherm data of tylosin on original maize straw fit a linear model well, while Freundlich models were more suitable for maize straw modified by manganese oxides and maize straw modified by iron and manganese oxides. The pH, ionic strength and temperature can affect the sorption process. The sorption mechanisms of tylosin on iron and manganese oxides modified maize straw were attribute to the surface complexes, electrostatic interactions, H bonding and hydrophobic interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Analysis of B Cell Repertoire Dynamics Following Hepatitis B Vaccination in Humans, and Enrichment of Vaccine-specific Antibody Sequences

Directory of Open Access Journals (Sweden)

Jacob D. Galson

2015-12-01

Full Text Available Generating a diverse B cell immunoglobulin repertoire is essential for protection against infection. The repertoire in humans can now be comprehensively measured by high-throughput sequencing. Using hepatitis B vaccination as a model, we determined how the total immunoglobulin sequence repertoire changes following antigen exposure in humans, and compared this to sequences from vaccine-specific sorted cells. Clonal sequence expansions were seen 7 days after vaccination, which correlated with vaccine-specific plasma cell numbers. These expansions caused an increase in mutation, and a decrease in diversity and complementarity-determining region 3 sequence length in the repertoire. We also saw an increase in sequence convergence between participants 14 and 21 days after vaccination, coinciding with an increase of vaccine-specific memory cells. These features allowed development of a model for in silico enrichment of vaccine-specific sequences from the total repertoire. Identifying antigen-specific sequences from total repertoire data could aid our understanding B cell driven immunity, and be used for disease diagnostics and vaccine evaluation.

(SSR) markers for drought tolerance in maize

African Journals Online (AJOL)

Maize is moderately sensitive to drought. Drought affects virtually all aspects of maize growth in varying degrees at all stages, from germination to maturity. Tolerance to drought is genetically and physiologically complicated and inherited quantitatively. Application of molecular-marker aided selection technique for ...

[Development of specific and degenerated primers to CesA genes encoding flax (Linum usitatissimum L.) cellulose synthase].

Science.gov (United States)

Grushetskaia, Z E; Lemesh, V A; Khotyleva, L V

2010-01-01

Cellulose synthase catalytic subunit genes, CesA, have been discovered in several higher plant species, and it has been shown that the CesA gene family has multiple members. HVR2 fragment of these genes determine the class specificity of the CESA protein and its participation in the primary or secondary cell wall synthesis. The aim of this study was development of specific and degenerated primers to flax CesA gene fragments leading to obtaining the class specific HVR2 region of the gene. Two pairs of specific primers to the certain fragments of CesA-1 and CesA-6 genes and one pair of degenerated primers to HVR2 region of all flax CesA genes were developed basing on comparison of six CesA EST sequences of flax and full cDNA sequences of Arabidopsis, poplar, maize and cotton plants, obtained from GenBank. After amplification of flax cDNA, the bands of expected size were detected (201 and 300 b.p. for the CesA-1 and CesA-6, and 600 b.p. for the HVR2 region of CesA respectively). The developed markers can be used for cloning and sequencing of flax CesA genes, identifying their number in flax genome, tissue and stage specificity.

Transcriptomic Analysis of Intestinal Tissues from Two 90-Day Feeding Studies in Rats Using Genetically Modified MON810 Maize Varieties.

Science.gov (United States)

Sharbati, Jutta; Bohmer, Marc; Bohmer, Nils; Keller, Andreas; Backes, Christina; Franke, Andre; Steinberg, Pablo; Zeljenková, Dagmar; Einspanier, Ralf

2017-01-01

Background: Global as well as specific expression profiles of selected rat tissues were characterized to assess the safety of genetically modified (GM) maize MON810 containing the insecticidal protein Cry1Ab. Gene expression was evaluated by use of Next Generation Sequencing (NGS) as well as RT-qPCR within rat intestinal tissues based on mandatory 90-day rodent feeding studies. In parallel to two 90-day feeding studies, the transcriptional response of rat tissues was assessed as another endpoint to enhance the mechanistic interpretation of GM feeding studies and/or to facilitate the generation of a targeted hypothesis. Rats received diets containing 33% GM maize (MON810) or near-isogenic control maize. As a site of massive exposure to ingested feed the transcriptomic response of ileal and colonic tissue was profiled via RT-qPCR arrays targeting apoptosis, DNA-damage/repair, unfolded protein response (UPR). For global RNA profiling of rat ileal tissue, we applied NGS. Results: No biological response to the GM-diet was observed in male and in female rat tissues. Transcriptome wide analysis of gene expression by RNA-seq confirmed these findings. Nevertheless, gene ontology (GO) analysis clearly associated a set of distinctly regulated transcripts with circadian rhythms. We confirmed differential expression of circadian clock genes using RT-qPCR and immunoassays for selected factors, thereby indicating physiological effects caused by the time point of sampling. Conclusion: Prediction of potential unintended effects of GM-food/feed by transcriptome based profiling of intestinal tissue presents a novel approach to complement classical toxicological testing procedures. Including the detection of alterations in signaling pathways in toxicity testing procedures may enhance the confidence in outcomes of toxicological trials. In this study, no significant GM-related changes in intestinal expression profiles were found in rats fed GM-maize MON810. Relevant alterations of

Cercospora zeina from Maize in South Africa Exhibits High Genetic Diversity and Lack of Regional Population Differentiation.

Science.gov (United States)

Muller, Mischa F; Barnes, Irene; Kunene, Ncobile T; Crampton, Bridget G; Bluhm, Burton H; Phillips, Sonia M; Olivier, Nicholas A; Berger, Dave K

2016-10-01

South Africa is one of the leading maize-producing countries in sub-Saharan Africa. Since the 1980s, Cercospora zeina, a causal agent of gray leaf spot of maize, has become endemic in South Africa, and is responsible for substantial yield reductions. To assess genetic diversity and population structure of C. zeina in South Africa, 369 isolates were collected from commercial maize farms in three provinces (KwaZulu-Natal, Mpumalanga, and North West). These isolates were evaluated with 14 microsatellite markers and species-specific mating type markers that were designed from draft genome sequences of C. zeina isolates from Africa (CMW 25467) and the United States (USPA-4). Sixty alleles were identified across 14 loci, and gene diversity values within each province ranged from 0.18 to 0.35. High levels of gene flow were observed (Nm = 5.51), and in a few cases, identical multilocus haplotypes were found in different provinces. Overall, 242 unique multilocus haplotypes were identified with a low clonal fraction of 34%. No distinct population clusters were identified using STRUCTURE, principal coordinate analysis, or Weir's theta θ statistic. The lack of population differentiation was supported by analysis of molecular variance tests, which indicated that only 2% of the variation was attributed to variability between populations from each province. Mating type ratios of MAT1-1 and MAT1-2 idiomorphs from 335 isolates were not significantly different from a 1:1 ratio in all provinces, which provided evidence for sexual reproduction. The draft genome of C. zeina CMW 25467 exhibited a complete genomic copy of the MAT1-1 idiomorph as well as exonic fragments of MAT genes from both idiomorphs. The high level of gene diversity, shared haplotypes at different geographical locations within South Africa, and presence of both MAT idiomorphs at all sites indicates widespread dispersal of C. zeina between maize fields in the country as well as evidence for sexual recombination. The

A maize resistance gene functions against bacterial streak disease in rice

OpenAIRE

Zhao, Bingyu; Lin, Xinghua; Poland, Jesse; Trick, Harold; Leach, Jan; Hulbert, Scot

2005-01-01

Although cereal crops all belong to the grass family (Poacea), most of their diseases are specific to a particular species. Thus, a given cereal species is typically resistant to diseases of other grasses, and this nonhost resistance is generally stable. To determine the feasibility of transferring nonhost resistance genes (R genes) between distantly related grasses to control specific diseases, we identified a maize R gene that recognizes a rice pathogen, Xanthomonas oryzae pv. oryzicola, wh...

A comparative study on infestation of three varieties of maize ( Zea ...

African Journals Online (AJOL)

A study was carried out to study the infestation of three maize varieties (Maize suwan I–Y, Maize T2 USR – White single cross and Maize suwan 123) by Sitophilus zeamais Motsch. Infestation was assessed by counting the numbers of alive and dead adults and the number of infested and uninfested seeds. It was found out ...

Nitrogen assimilation system in maize is regulated by developmental and tissue-specific mechanisms

KAUST Repository

Plett, Darren

2016-08-10

Key message: We found metabolites, enzyme activities and enzyme transcript abundances vary significantly across the maize lifecycle, but weak correlation exists between the three groups. We identified putative genes regulating nitrate assimilation. Abstract: Progress in improving nitrogen (N) use efficiency (NUE) of crop plants has been hampered by the complexity of the N uptake and utilisation systems. To understand this complexity we measured the activities of seven enzymes and ten metabolites related to N metabolism in the leaf and root tissues of Gaspe Flint maize plants grown in 0.5 or 2.5 mM NO3 − throughout the lifecycle. The amino acids had remarkably similar profiles across the lifecycle except for transient responses, which only appeared in the leaves for aspartate or in the roots for asparagine, serine and glycine. The activities of the enzymes for N assimilation were also coordinated to a certain degree, most noticeably with a peak in root activity late in the lifecycle, but with wide variation in the activity levels over the course of development. We analysed the transcriptional data for gene sets encoding the measured enzymes and found that, unlike the enzyme activities, transcript levels of the corresponding genes did not exhibit the same coordination across the lifecycle and were only weakly correlated with the levels of various amino acids or individual enzyme activities. We identified gene sets which were correlated with the enzyme activity profiles, including seven genes located within previously known quantitative trait loci for enzyme activities and hypothesise that these genes are important for the regulation of enzyme activities. This work provides insights into the complexity of the N assimilation system throughout development and identifies candidate regulatory genes, which warrant further investigation in efforts to improve NUE in crop plants. © 2016, Springer Science+Business Media Dordrecht.

Nitrogen assimilation system in maize is regulated by developmental and tissue-specific mechanisms

KAUST Repository

Plett, Darren; Holtham, Luke; Baumann, Ute; Kalashyan, Elena; Francis, Karen; Enju, Akiko; Toubia, John; Roessner, Ute; Bacic, Antony; Rafalski, Antoni; Dhugga, Kanwarpal S.; Tester, Mark A.; Garnett, Trevor; Kaiser, Brent N.

2016-01-01

Key message: We found metabolites, enzyme activities and enzyme transcript abundances vary significantly across the maize lifecycle, but weak correlation exists between the three groups. We identified putative genes regulating nitrate assimilation. Abstract: Progress in improving nitrogen (N) use efficiency (NUE) of crop plants has been hampered by the complexity of the N uptake and utilisation systems. To understand this complexity we measured the activities of seven enzymes and ten metabolites related to N metabolism in the leaf and root tissues of Gaspe Flint maize plants grown in 0.5 or 2.5 mM NO3 − throughout the lifecycle. The amino acids had remarkably similar profiles across the lifecycle except for transient responses, which only appeared in the leaves for aspartate or in the roots for asparagine, serine and glycine. The activities of the enzymes for N assimilation were also coordinated to a certain degree, most noticeably with a peak in root activity late in the lifecycle, but with wide variation in the activity levels over the course of development. We analysed the transcriptional data for gene sets encoding the measured enzymes and found that, unlike the enzyme activities, transcript levels of the corresponding genes did not exhibit the same coordination across the lifecycle and were only weakly correlated with the levels of various amino acids or individual enzyme activities. We identified gene sets which were correlated with the enzyme activity profiles, including seven genes located within previously known quantitative trait loci for enzyme activities and hypothesise that these genes are important for the regulation of enzyme activities. This work provides insights into the complexity of the N assimilation system throughout development and identifies candidate regulatory genes, which warrant further investigation in efforts to improve NUE in crop plants. © 2016, Springer Science+Business Media Dordrecht.

Effects of temperature changes on maize production in Mozambique

Science.gov (United States)

Harrison, L.; Michaelsen, J.; Funk, Chris; Husak, G.

2011-01-01

We examined intraseasonal changes in maize phenology and heat stress exposure over the 1979-2008 period, using Mozambique meteorological station data and maize growth requirements in a growing degree-day model. Identifying historical effects of warming on maize growth is particularly important in Mozambique because national food security is highly dependent on domestic food production, most of which is grown in already warm to hot environments. Warming temperatures speed plant development, shortening the length of growth periods necessary for optimum plant and grain size. This faster phenological development also alters the timing of maximum plant water demand. In hot growing environments, temperature increases during maize pollination threaten to make midseason crop failure the norm. In addition to creating a harsher thermal environment, we find that early season temperature increases have caused the maize reproductive period to start earlier, increasing the risk of heat and water stress. Declines in time to maize maturation suggest that, independent of effects to water availability, yield potential is becoming increasingly limited by warming itself. Regional variations in effects are a function of the timing and magnitude of temperature increases and growing season characteristics. Continuation of current climatic trends could induce substantial yield losses in some locations. Farmers could avoid some losses through simple changes to planting dates and maize varietal types.

Seed treatments enhance photosynthesis in maize seedlings by reducing infection with Fusarium spp. and consequent disease development in maize

Science.gov (United States)

The effects of a seed treatment on early season growth, seedling disease development, incidence Fusarium spp. infection, and photosynthetic performance of maize were evaluated at two locations in Iowa in 2007. Maize seed was either treated with Cruiser 2Extreme 250 ® (fludioxonil + azoxystrobin + me...

PERFORMANCE OF MAIZE (ZEA MAYS) CULTIVARS AS ...

African Journals Online (AJOL)

IBUKUN

reported to have low remobilisation efficiency and reduced plasticity of seed weight to assimilate availability ... have indicated that the use of organo-mineral fertiliser in maize and melon gave high relative .... The soil physical and chemical characteristics of ..... yield in maize by examining genetic improvement and heterosis.

Fate of Transgenic DNA from Orally Administered Bt MON810 Maize and Effects on Immune Response and Growth in Pigs

Science.gov (United States)

Walsh, Maria C.; Buzoianu, Stefan G.; Gardiner, Gillian E.; Rea, Mary C.; Gelencsér, Eva; Jánosi, Anna; Epstein, Michelle M.; Ross, R. Paul; Lawlor, Peadar G.

2011-01-01

We assessed the effect of short-term feeding of genetically modified (GM: Bt MON810) maize on immune responses and growth in weanling pigs and determined the fate of the transgenic DNA and protein in-vivo. Pigs were fed a diet containing 38.9% GM or non-GM isogenic parent line maize for 31 days. We observed that IL-12 and IFNγ production from mitogenic stimulated peripheral blood mononuclear cells decreased (PGM maize exposure. While Cry1Ab-specific IgG and IgA were not detected in the plasma of GM maize-fed pigs, the detection of the cry1Ab gene and protein was limited to the gastrointestinal digesta and was not found in the kidneys, liver, spleen, muscle, heart or blood. Feeding GM maize to weanling pigs had no effect on growth performance or body weight. IL-6 and IL-4 production from isolated splenocytes were increased (PGM maize while the proportion of CD4+ T cells in the spleen decreased. In the ileum, the proportion of B cells and macrophages decreased while the proportion of CD4+ T cells increased in GM maize-fed pigs. IL-8 and IL-4 production from isolated intraepithelial and lamina propria lymphocytes were also increased (PGM maize. In conclusion, there was no evidence of cry1Ab gene or protein translocation to the organs and blood of weaning pigs. The growth of pigs was not affected by feeding GM maize. Alterations in immune responses were detected; however, their biologic relevance is questionable. PMID:22132091

Deregulation of Lesotho's maize market

OpenAIRE

van Schalkwyk, Herman D.; van Zyl, Johan; Botha, P.W.; Bayley, B.

1997-01-01

During the past year, there have been major policy reforms in Lesotho and South Africa with respect to maize pricing and marketing. In Lesotho the impact of deregulation on producers, consumers and government revenues was substantially lower than it should have been, and as a result Lesotho was not able to reap the full benefits of these changes. This is partly because information on the changes to the maize marketing system did not reach the potential beneficiaries of the new system. Free an...

Molecular phylogenetic and expression analysis of the complete WRKY transcription factor family in maize.

Science.gov (United States)

Wei, Kai-Fa; Chen, Juan; Chen, Yan-Feng; Wu, Ling-Juan; Xie, Dao-Xin

2012-04-01

The WRKY transcription factors function in plant growth and development, and response to the biotic and abiotic stresses. Although many studies have focused on the functional identification of the WRKY transcription factors, much less is known about molecular phylogenetic and global expression analysis of the complete WRKY family in maize. In this study, we identified 136 WRKY proteins coded by 119 genes in the B73 inbred line from the complete genome and named them in an orderly manner. Then, a comprehensive phylogenetic analysis of five species was performed to explore the origin and evolutionary patterns of these WRKY genes, and the result showed that gene duplication is the major driving force for the origin of new groups and subgroups and functional divergence during evolution. Chromosomal location analysis of maize WRKY genes indicated that 20 gene clusters are distributed unevenly in the genome. Microarray-based expression analysis has revealed that 131 WRKY transcripts encoded by 116 genes may participate in the regulation of maize growth and development. Among them, 102 transcripts are stably expressed with a coefficient of variation (CV) value of WRKY genes with the CV value of >15% are further analysed to discover new organ- or tissue-specific genes. In addition, microarray analyses of transcriptional responses to drought stress and fungal infection showed that maize WRKY proteins are involved in stress responses. All these results contribute to a deep probing into the roles of WRKY transcription factors in maize growth and development and stress tolerance.

Growing sensitivity of maize to water scarcity under climate change.

Science.gov (United States)

Meng, Qingfeng; Chen, Xinping; Lobell, David B; Cui, Zhenling; Zhang, Yi; Yang, Haishun; Zhang, Fusuo

2016-01-25

Climate change can reduce crop yields and thereby threaten food security. The current measures used to adapt to climate change involve avoiding crops yield decrease, however, the limitations of such measures due to water and other resources scarcity have not been well understood. Here, we quantify how the sensitivity of maize to water availability has increased because of the shift toward longer-maturing varieties during last three decades in the Chinese Maize Belt (CMB). We report that modern, longer-maturing varieties have extended the growing period by an average of 8 days and have significantly offset the negative impacts of climate change on yield. However, the sensitivity of maize production to water has increased: maize yield across the CMB was 5% lower with rainfed than with irrigated maize in the 1980s and was 10% lower (and even >20% lower in some areas) in the 2000s because of both warming and the increased requirement for water by the longer-maturing varieties. Of the maize area in China, 40% now fails to receive the precipitation required to attain the full yield potential. Opportunities for water saving in maize systems exist, but water scarcity in China remains a serious problem.

Effect and fate of lindane in maize plant

International Nuclear Information System (INIS)

Bennaceur, M.; Ghezal, F.; Klaa, K.

1992-10-01

The fate and effect of lindane in maize plant, soil and predators were studied following insecticide application under field conditions. Respectively 84,2% and 93,3% of lindane residues were lost after 2 and 4 months in soil after treatment. About 90% of the insecticide was lost after one month in maize plant. Lindane residues were present in maize grains (0,205ppm). Lindane decreases the density of many predators in soils such as species of collembola, coccinellidae, formicidae, coleoptera

Combining Maize Base Germplasm for Cold Tolerance Breeding

OpenAIRE

Rodríguez Graña, Víctor Manuel; Butrón Gómez, Ana María; Sandoya Miranda, Germán; Ordás Pérez, Amando; Revilla Temiño, Pedro

2007-01-01

Early planting can contribute to increased grain yield of maize (Zea mays L.), but it requires cold tolerance. A limited number of cold-tolerant maize genotypes have been reported. The objectives of this study were to test a new strategy to improve cold tolerance in maize searching for broad x narrow genetic combinations that may be useful as base populations for breeding programs, to compare genotype performance under cold-controlled and field conditions, and to establish the major genetic e...

Status and prospects of maize research in Nepal

OpenAIRE

Govind KC; Tika B. Karki; Jiban Shrestha; Buddhi B. Achhami

2015-01-01

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 ar...

Utilizing virus-induced gene silencing for the functional characterization of maize genes during infection with the fungal pathogen Ustilago maydis.

Science.gov (United States)

van der Linde, Karina; Doehlemann, Gunther

2013-01-01

While in dicotyledonous plants virus-induced gene silencing (VIGS) is well established to study plant-pathogen interaction, in monocots only few examples of efficient VIGS have been reported so far. One of the available systems is based on the brome mosaic virus (BMV) which allows gene silencing in different cereals including barley (Hordeum vulgare), wheat (Triticum aestivum), and maize (Zea mays).Infection of maize plants by the corn smut fungus Ustilago maydis leads to the formation of large tumors on stem, leaves, and inflorescences. During this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed comprehensive and stage-specific changes in host gene expression during disease progression.To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a VIGS system based on the Brome mosaic virus (BMV) to maize at conditions that allow successful U. maydis infection of BMV pre-infected maize plants. This setup enables quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (q(RT)-PCR)-based readout.

Genomic variation in recently collected maize landraces from Mexico

Science.gov (United States)

Arteaga, María Clara; Moreno-Letelier, Alejandra; Mastretta-Yanes, Alicia; Vázquez-Lobo, Alejandra; Breña-Ochoa, Alejandra; Moreno-Estrada, Andrés; Eguiarte, Luis E.; Piñero, Daniel

2015-01-01

The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (HE = 0.234 to 0.318 (mean 0.311), while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (HE = 0.262 and 0.234, respectively). The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law. PMID:26981357

Flooding tolerance in interspecific introgression lines containing chromosome segments from teosinte (Zea nicaraguensis) in maize (Zea mays subsp. mays)

Science.gov (United States)

Mano, Y.; Omori, F.

2013-01-01

Background and Aims Nicaraguan teosinte (Zea nicaraguensis), a species found in frequently flooded areas, provides useful germplasm for breeding flooding-tolerant maize (Z. mays subsp. mays). The objective of this study was to select flooding-tolerant lines using a library of introgression lines (ILs), each containing a chromosome segment from Z. nicaraguensis in the maize inbred line Mi29. Methods To produce the ILs, a single F1 plant derived from a cross between maize Mi29 and Z. nicaraguensis was backcrossed to Mi29 three times, self-pollinated four times and genotyped using simple sequence repeat markers. Flooding tolerance was evaluated at the seedling stage under reducing soil conditions. Key Results By backcrossing and selfing, a series of 45 ILs were developed covering nearly the entire maize genome. Five flooding-tolerant lines were identified from among the ILs by evaluating leaf injury. Among these, line IL#18, containing a Z. nicaraguensis chromosome segment on the long arm of chromosome 4, showed the greatest tolerance to flooding, suggesting the presence of a major quantitative trait locus (QTL) in that region. The presence of the QTL was verified by examining flooding tolerance in a population segregating for the candidate region of chromosome 4. There was no significant relationship between the capacity to form constitutive aerenchyma and flooding tolerance in the ILs, indicating the presence of other factors related to flooding tolerance under reducing soil conditions. Conclusions A flooding-tolerant genotype, IL#18, was identified; this genotype should be useful for maize breeding. In addition, because the chromosome segments of Z. nicaraguensis in the ILs cover nearly the entire genome and Z. nicaraguensis possesses several unique traits related to flooding tolerance, the ILs should be valuable material for additional QTL detection and the development of flooding-tolerant maize lines. PMID:23877074

Flooding tolerance in interspecific introgression lines containing chromosome segments from teosinte (Zea nicaraguensis) in maize (Zea mays subsp. mays).

Science.gov (United States)

Mano, Y; Omori, F

2013-10-01

Nicaraguan teosinte (Zea nicaraguensis), a species found in frequently flooded areas, provides useful germplasm for breeding flooding-tolerant maize (Z. mays subsp. mays). The objective of this study was to select flooding-tolerant lines using a library of introgression lines (ILs), each containing a chromosome segment from Z. nicaraguensis in the maize inbred line Mi29. To produce the ILs, a single F1 plant derived from a cross between maize Mi29 and Z. nicaraguensis was backcrossed to Mi29 three times, self-pollinated four times and genotyped using simple sequence repeat markers. Flooding tolerance was evaluated at the seedling stage under reducing soil conditions. By backcrossing and selfing, a series of 45 ILs were developed covering nearly the entire maize genome. Five flooding-tolerant lines were identified from among the ILs by evaluating leaf injury. Among these, line IL#18, containing a Z. nicaraguensis chromosome segment on the long arm of chromosome 4, showed the greatest tolerance to flooding, suggesting the presence of a major quantitative trait locus (QTL) in that region. The presence of the QTL was verified by examining flooding tolerance in a population segregating for the candidate region of chromosome 4. There was no significant relationship between the capacity to form constitutive aerenchyma and flooding tolerance in the ILs, indicating the presence of other factors related to flooding tolerance under reducing soil conditions. A flooding-tolerant genotype, IL#18, was identified; this genotype should be useful for maize breeding. In addition, because the chromosome segments of Z. nicaraguensis in the ILs cover nearly the entire genome and Z. nicaraguensis possesses several unique traits related to flooding tolerance, the ILs should be valuable material for additional QTL detection and the development of flooding-tolerant maize lines.

Assessment of the potential for gene flow from transgenic maize (Zea mays L.) to eastern gamagrass (Tripsacum dactyloides L.).

Science.gov (United States)

Lee, Moon-Sub; Anderson, Eric K; Stojšin, Duška; McPherson, Marc A; Baltazar, Baltazar; Horak, Michael J; de la Fuente, Juan Manuel; Wu, Kunsheng; Crowley, James H; Rayburn, A Lane; Lee, D K

2017-08-01

Eastern gamagrass (Tripsacum dactyloides L.) belongs to the same tribe of the Poaceae family as maize (Zea mays L.) and grows naturally in the same region where maize is commercially produced in the USA. Although no evidence exists of gene flow from maize to eastern gamagrass in nature, experimental crosses between the two species were produced using specific techniques. As part of environmental risk assessment, the possibility of transgene flow from maize to eastern gamagrass populations in nature was evaluated with the objectives: (1) to assess the seeds of eastern gamagrass populations naturally growing near commercial maize fields for the presence of a transgenic glyphosate-tolerance gene (cp4 epsps) that would indicate cross-pollination between the two species, and (2) to evaluate the possibility of interspecific hybridization between transgenic maize used as male parent and eastern gamagrass used as female parent. A total of 46,643 seeds from 54 eastern gamagrass populations collected in proximity of maize fields in Illinois, USA were planted in a field in 2014 and 2015. Emerged seedlings were treated with glyphosate herbicide and assessed for survival. An additional 48,000 seeds from the same 54 eastern gamagrass populations were tested for the presence of the cp4 epsps transgene markers using TaqMan ® PCR method. The results from these trials showed that no seedlings survived the herbicide treatment and no seed indicated presence of the herbicide tolerant cp4 epsps transgene, even though these eastern gamagrass populations were exposed to glyphosate-tolerant maize pollen for years. Furthermore, no interspecific hybrid seeds were produced from 135 hand-pollination attempts involving 1529 eastern gamagrass spikelets exposed to maize pollen. Together, these results indicate that there is no evidence of gene flow from maize to eastern gamagrass in natural habitats. The outcome of this study should be taken in consideration when assessing for environmental

Net energy value of maize ethanol as a response to different climate and soil conditions in the southeastern USA

Energy Technology Data Exchange (ETDEWEB)

Persson, Tomas; Garcia y Garcia, Axel; Paz, Joel O.; Hoogenboom, Gerrit [Department of Biological and Agricultural Engineering, 1109 Experiment Street, The University of Georgia, Griffin, GA 30223 (United States); Jones, James W. [Department of Agricultural and Biological Engineering, Frazier Rogers Hall, University of Florida, Gainesville, FL 32611 (United States)

2009-08-15

A recent increase in the demand for bio-ethanol has sparked maize production in the USA and other countries across the world. The net energy value (NEV), i.e. the energy output in ethanol and co-products after accounting for energy input requirements in the production chain of ethanol, is a measure of its sustainability. Grain yield of maize, which varies substantially across different climate and soil conditions, greatly impacts the ethanol NEV. The objectives of this study were to determine i) the NEV of ethanol produced from maize grown in four production regions in the southeastern USA and, ii) the specific impact of local soil variability under the same climate conditions within the four regions on the NEV of maize-ethanol. Maize yield was simulated with the Cropping System Model (CSM)-CERES-Maize model for soil and weather conditions, and management practices representing Bulloch, Floyd, Laurens and Mitchell counties, Georgia, USA. The calculation of ethanol NEV took into account the energy inputs and outputs of the entire ethanol production chain, and was based on the crop simulations. There were statistically significant differences in ethanol NEV among the counties, and within counties due to local soil variability. Differences in ethanol NEV among counties were partially due to different transportation distances. Based on the results of this study, it was concluded that maize-ethanol NEV can be increased by accounting for the soil and climate factors in the feedstock production and by locating ethanol-processing facilities in regions with soil and climate conditions that are favorable for ethanol-maize production. (author)

Is Investment in Maize Research Balanced and Justified? An Empirical Study

Directory of Open Access Journals (Sweden)

Hari Krishna Shrestha

2016-12-01

Full Text Available The objective of this study was to investigate whether the investment in maize research was adequate and balanced in Nepalese context. Resource use in maize research was empirically studied with standard congruency analysis by using Full Time Equivalent (FTE of researchers as a proxy measure of investment. The number of researchers involved in maize was 61 but it was only 21.25 on FTE basis, indicating that full time researchers were very few as compared to the cultivated area of maize in the country. Statistical analysis revealed that the investment in maize research was higher in Tarai and lower in the Hills. Congruency index on actual production basis was found low across the eco-zones and even lower across the geographical regions indicating that the investment in maize research was a mismatch and not justified. While adjusted with the equity factor and the research progress factor in the analysis substantial difference was not found in congruency index. This study recommends that substantial increase in investment in maize research is needed with balanced and justified manner across the eco-zones and the geographical regions. Hills need special attention to increase the investment as maize output value is higher in this eco-zone. Eastern and western regions also need increased investment in maize according to their contribution in the output value.

Developing a database for maize variety in Nigeria | Daniel | Moor ...

African Journals Online (AJOL)

Performance data of maize varieties at different locations needs to be accurate and accessible to stimulate the improvement of the Nigerian maize seed system. This paper describes a database model to implement a simple computerized information system for maize varieties and their performance at various locations in ...

Rapid detection and purification of sequence specific DNA binding proteins using magnetic separation

Directory of Open Access Journals (Sweden)

TIJANA SAVIC

2006-02-01

Full Text Available In this paper, a method for the rapid identification and purification of sequence specific DNA binding proteins based on magnetic separation is presented. This method was applied to confirm the binding of the human recombinant USF1 protein to its putative binding site (E-box within the human SOX3 protomer. It has been shown that biotinylated DNA attached to streptavidin magnetic particles specifically binds the USF1 protein in the presence of competitor DNA. It has also been demonstrated that the protein could be successfully eluted from the beads, in high yield and with restored DNA binding activity. The advantage of these procedures is that they could be applied for the identification and purification of any high-affinity sequence-specific DNA binding protein with only minor modifications.

Global maize trade and food security: implications from a social network model.

Science.gov (United States)

Wu, Felicia; Guclu, Hasan

2013-12-01

In this study, we developed a social network model of the global trade of maize: one of the most important food, feed, and industrial crops worldwide, and critical to food security. We used this model to analyze patterns of maize trade among nations, and to determine where vulnerabilities in food security might arise if maize availability was decreased due to factors such as diversion to nonfood uses, climatic factors, or plant diseases. Using data on imports and exports from the U.N. Commodity Trade Statistics Database for each year from 2000 to 2009 inclusive, we summarized statistics on volumes of maize trade between pairs of nations for 217 nations. There is evidence of market segregation among clusters of nations; with three prominent clusters representing Europe, Brazil and Argentina, and the United States. The United States is by far the largest exporter of maize worldwide, whereas Japan and the Republic of Korea are the largest maize importers. In particular, the star-shaped cluster of the network that represents U.S. maize trade to other nations indicates the potential for food security risks because of the lack of trade these other nations conduct with other maize exporters. If a scenario arose in which U.S. maize could not be exported in as large quantities, maize supplies in many nations could be jeopardized. We discuss this in the context of recent maize ethanol production and its attendant impacts on food prices elsewhere worldwide. © 2013 Society for Risk Analysis.

Studies on the traditional methods of production of maize tuwo (a ...

African Journals Online (AJOL)

African Journal of Food, Agriculture, Nutrition and Development ... on the quality characteristics of maize tuwo (a Nigerian nonfermented maize dumpling) ... The sequential mixing of flour and water during maize tuwo preparation should also ...

Sequence specific electronic conduction through polyion-stabilized double-stranded DNA in nanoscale break junctions

International Nuclear Information System (INIS)

Mahapatro, Ajit K; Jeong, Kyung J; Lee, Gil U; Janes, David B

2007-01-01

This paper presents a study of sequence specific electronic conduction through short (15-base-pair) double-stranded (ds) DNA molecules, measured by immobilizing 3 ' -thiol-derivatized DNAs in nanometre scale gaps between gold electrodes. The polycation spermidine was used to stabilize the ds-DNA structure, allowing electrical measurements to be performed in a dry state. For specific sequences, the conductivity was observed to scale with the surface density of immobilized DNA, which can be controlled by the buffer concentration. A series of 15-base DNA oligonucleotide pairs, in which the centre sequence of five base pairs was changed from G:C to A:T pairs, has been studied. The conductivity per molecule is observed to decrease exponentially with the number of adjacent A:T pairs replacing G:C pairs, consistent with a barrier at the A:T sites. Conductance-based devices for short DNA sequences could provide sensing approaches with direct electrical readout, as well as label-free detection

Micropatterning stretched and aligned DNA for sequence-specific nanolithography

Science.gov (United States)

Petit, Cecilia Anna Paulette

Techniques for fabricating nanostructured materials can be categorized as either "top-down" or "bottom-up". Top-down techniques use lithography and contact printing to create patterned surfaces and microfluidic channels that can corral and organize nanoscale structures, such as molecules and nanorods in contrast; bottom-up techniques use self-assembly or molecular recognition to direct the organization of materials. A central goal in nanotechnology is the integration of bottom-up and top-down assembly strategies for materials development, device design; and process integration. With this goal in mind, we have developed strategies that will allow this integration by using DNA as a template for nanofabrication; two top-down approaches allow the placement of these templates, while the bottom-up technique uses the specific sequence of bases to pattern materials along each strand of DNA. Our first top-down approach, termed combing of molecules in microchannels (COMMIC), produces microscopic patterns of stretched and aligned molecules of DNA on surfaces. This process consists of passing an air-water interface over end adsorbed molecules inside microfabricated channels. The geometry of the microchannel directs the placement of the DNA molecules, while the geometry of the airwater interface directs the local orientation and curvature of the molecules. We developed another top-down strategy for creating micropatterns of stretched and aligned DNA using surface chemistry. Because DNA stretching occurs on hydrophobic surfaces, this technique uses photolithography to pattern vinyl-terminated silanes on glass When these surface-, are immersed in DNA solution, molecules adhere preferentially to the silanized areas. This approach has also proven useful in patterning protein for cell adhesion studies. Finally, we describe the use of these stretched and aligned molecules of DNA as templates for the subsequent bottom-up construction of hetero-structures through hybridization

Nitrogen effects on maize yield following groundnut in rotation on ...

African Journals Online (AJOL)

Rotating maize (Zea mays L.) with groundnut (Arachis hypogaea L.) has been proposed as a way to maintain soil fertility and prevent maize productivity declines in the smallholder cropping systems of sub-humid Zimbabwe. Field experiments with fertilizer-N on maize in rotation with groundnut were conducted at three ...

Quantitative trait loci for resistance to Maize rayado fino virus

Science.gov (United States)

Maize rayado fino virus (MRFV) causes one of the most important virus diseases of maize in regions of Mexico, Central and South America, where it causes moderate to severe yield losses. The virus is found from the southern United States. to northern Argentina where its vector, the maize leafhopper D...

Effects of feeding Bt maize to sows during gestation and lactation on maternal and offspring immunity and fate of transgenic material.

Directory of Open Access Journals (Sweden)

Stefan G Buzoianu

Full Text Available BACKGROUND: We aimed to determine the effect of feeding transgenic maize to sows during gestation and lactation on maternal and offspring immunity and to assess the fate of transgenic material. METHODOLOGY/PRINCIPAL FINDINGS: On the day of insemination, sows were assigned to one of two treatments (n = 12/treatment; 1 non-Bt control maize diet or 2 Bt-MON810 maize diet, which were fed for ~143 days throughout gestation and lactation. Immune function was assessed by leukocyte phenotyping, haematology and Cry1Ab-specific antibody presence in blood on days 0, 28 and 110 of gestation and at the end of lactation. Peripheral-blood mononuclear cell cytokine production was investigated on days 28 and 110 of gestation. Haematological analysis was performed on offspring at birth (n = 12/treatment. Presence of the cry1Ab transgene was assessed in sows' blood and faeces on day 110 of gestation and in blood and tissues of offspring at birth. Cry1Ab protein presence was assessed in sows' blood during gestation and lactation and in tissues of offspring at birth. Blood monocyte count and percentage were higher (P<0.05, while granulocyte percentage was lower (P<0.05 in Bt maize-fed sows on day 110 of gestation. Leukocyte count and granulocyte count and percentage were lower (P<0.05, while lymphocyte percentage was higher (P<0.05 in offspring of Bt maize-fed sows. Bt maize-fed sows had a lower percentage of monocytes on day 28 of lactation and of CD4(+CD8(+ lymphocytes on day 110 of gestation, day 28 of lactation and overall (P<0.05. Cytokine production was similar between treatments. Transgenic material or Cry1Ab-specific antibodies were not detected in sows or offspring. CONCLUSIONS/SIGNIFICANCE: Treatment differences observed following feeding of Bt maize to sows did not indicate inflammation or allergy and are unlikely to be of major importance. These results provide additional data for Bt maize safety assessment.

Effect of endosperm mutants on maize seed germination

Directory of Open Access Journals (Sweden)

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.

An upstream open reading frame represses expression of Lc, a member of the R/B family of maize transcriptional activators

Energy Technology Data Exchange (ETDEWEB)

Damiani, R.D. Jr.; Wessler, S.R. (Univ. of Georgia, Athens, GA (United States))

1993-09-01

The R/B genes of maize encode a family of basic helix-loop-helix proteins that determine where and when the anthocyanin-pigment pathway will be expressed in the plant. Previous studies showed that allelic diversity among family members reflects differences in gene expression, specifically in transcription initiation. The authors present evidence that the R gene Lc is under translational control. They demonstrate that the 235-nt transcript leader of Lc represses expression 25- to 30-fold in an in vivo assay. Repression is mediated by the presence in cis of a 38-codon upstream open reading frame. Furthermore, the coding capacity of the upstream open reading frame influences the magnitude of repression. It is proposed that translational control does not contribute to tissue specificity but prevents overexpression of the Lc protein. The diversity of promoter and 5' untranslated leader sequences among the R/B genes provides an opportunity to study the coevolution of transcriptional and translational mechanisms of gene regulation. 36 refs., 5 figs.

Exploring cost-effective maize integrated weed management ...

African Journals Online (AJOL)

Several production constraints have led to low yields (< 2.5 t ha-1) in maize (Zea mays L.) inUganda, among which are weeds. This study investigated the most cost-effective integrated weedmanagement (IWM) approach in maize in eastern Uganda. An experiment was conducted atIkulwe station, Mayuge in 2011 and 2012 ...

Assessment of Climate Suitability of Maize in South Korea

Science.gov (United States)

Hyun, S.; Choi, D.; Seo, B.

2017-12-01

Assessing suitable areas for crops would be useful to design alternate cropping systems as an adaptation option to climate change adaptation. Although suitable areas could be identified by using a crop growth model, it would require a number of input parameters including cultivar and soil. Instead, a simple climate suitability model, e.g., EcoCrop model, could be used for an assessment of climate suitability for a major grain crop. The objective of this study was to assess of climate suitability for maize using the EcoCrop model under climate change conditions in Korea. A long term climate data from 2000 - 2100 were compiled from weather data source. The EcoCrop model implemented in R was used to determine climate suitability index at each grid cell. Overall, the EcoCrop model tended to identify suitable areas for maize production near the coastal areas whereas the actual major production areas located in inland areas. It is likely that the discrepancy between assessed and actual crop production areas would result from the socioeconomic aspects of maize production. Because the price of maize is considerably low, maize has been grown in an area where moisture and temperature conditions would be less than optimum. In part, a simple algorithm to predict climate suitability for maize would caused a relatively large error in climate suitability assessment under the present climate conditions. In 2050s, the climate suitability for maize increased in a large areas in southern and western part of Korea. In particular, the plain areas near the coastal region had considerably greater suitability index in the future compared with mountainous areas. The expansion of suitable areas for maize would help crop production policy making such as the allocation of rice production area for other crops due to considerably less demand for the rice in Korea.

A Comprehensive Analysis of Alternative Splicing in Paleopolyploid Maize

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Wenbin Mei

2017-05-01

Full Text Available Identifying and characterizing alternative splicing (AS enables our understanding of the biological role of transcript isoform diversity. This study describes the use of publicly available RNA-Seq data to identify and characterize the global diversity of AS isoforms in maize using the inbred lines B73 and Mo17, and a related species, sorghum. Identification and characterization of AS within maize tissues revealed that genes expressed in seed exhibit the largest differential AS relative to other tissues examined. Additionally, differences in AS between the two genotypes B73 and Mo17 are greatest within genes expressed in seed. We demonstrate that changes in the level of alternatively spliced transcripts (intron retention and exon skipping do not solely reflect differences in total transcript abundance, and we present evidence that intron retention may act to fine-tune gene expression across seed development stages. Furthermore, we have identified temperature sensitive AS in maize and demonstrate that drought-induced changes in AS involve distinct sets of genes in reproductive and vegetative tissues. Examining our identified AS isoforms within B73 × Mo17 recombinant inbred lines (RILs identified splicing QTL (sQTL. The 43.3% of cis-sQTL regulated junctions are actually identified as alternatively spliced junctions in our analysis, while 10 Mb windows on each side of 48.2% of trans-sQTLs overlap with splicing related genes. Using sorghum as an out-group enabled direct examination of loss or conservation of AS between homeologous genes representing the two subgenomes of maize. We identify several instances where AS isoforms that are conserved between one maize homeolog and its sorghum ortholog are absent from the second maize homeolog, suggesting that these AS isoforms may have been lost after the maize whole genome duplication event. This comprehensive analysis provides new insights into the complexity of AS in maize.

Studies on maize inbred lines susceptibility to herbicides

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Stefanović Lidija

2010-01-01

Full Text Available This paper presents the analysis of results obtained during long- term studies on the response of maize inbred lines to herbicides. Under the agroecological conditions of Zemun Polje the response (reaction of maize inbred lines to herbicides of different classes was investigated. Biological tests were performed and some agronomic, morphological, physiological and biochemical parameters were determined when the response of maize inbred lines to herbicides was estimated. The use of active ingredients of herbicides from triazine, acetanilide, thiocarbamate to new chemical groups (sulfonylurea etc., have been resulted in changes in weed suppression and susceptibility of inbred lines. Obtained results show that effects of herbicides on susceptible maize genotypes can be different: they can slowdown the growth and development and affect the plant height; they can also affect the stages of the tassel and ear development and at the end they can reduced grain yield of the tested inbreds. Numerous studies confirmed the existence of differences in susceptibility level of maize genotypes in relation to herbicides. According to gained results the recommendations for growers are made on the possibility of the application of new herbicides in the hybrid seed production.

Ethylene Contributes to maize insect resistance1-Mediated Maize Defense against the Phloem Sap-Sucking Corn Leaf Aphid1[OPEN

Science.gov (United States)

Louis, Joe; Basu, Saumik; Varsani, Suresh; Castano-Duque, Lina; Jiang, Victoria; Williams, W. Paul; Felton, Gary W.; Luthe, Dawn S.

2015-01-01

Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack. Previously, it was reported that the synergistic combination of ethylene (ET) and jasmonic acid (JA) was required for accumulation of the maize insect resistance1 (mir1) gene product, a cysteine (Cys) proteinase that is a key defensive protein against chewing insect pests in maize (Zea mays). However, this study suggests that mir1-mediated resistance to corn leaf aphid (CLA; Rhopalosiphum maidis), a phloem sap-sucking insect pest, is independent of JA but regulated by the ET-signaling pathway. Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype, Mp708. Furthermore, Mp708 provided elevated levels of antibiosis (limits aphid population)- and antixenosis (deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines. Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA. Furthermore, foliar feeding by CLA rapidly sends defensive signal(s) to the roots that trigger belowground accumulation of the mir1, signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects. Collectively, our data indicate that ET-regulated mir1 transcript accumulation, uncoupled from JA, contributed to heightened resistance to CLA in maize. In addition, our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores. PMID:26253737

The economic implication of substituting cocoa pod husk for maize ...

African Journals Online (AJOL)

This saving was found to bridge the deficit between demand and supply as given by supplementation done by importing maize. The study concluded that by utilizing CPH in compounding various livestock feed rations, the high price of maize arising from excessive demand can be reduced. The limiting role of maize in ...

Performance of laying hens fed diets containing DAS-59122-7 maize grain compared with diets containing nontransgenic maize grain.

Science.gov (United States)

Jacobs, C M; Utterback, P L; Parsons, C M; Rice, D; Smith, B; Hinds, M; Liebergesell, M; Sauber, T

2008-03-01

An experiment using 216 Hy-Line W-36 pullets was conducted to evaluate transgenic maize grain containing the cry34Ab1 and cry35Ab1 genes from a Bacillus thuringiensis (Bt) strain and the phosphinothricin ace-tyltransferase (pat) gene from Streptomyces viridochromogenes. Expression of the cry34Ab1 and cry35Ab1 genes confers resistance to corn rootworms, and the pat gene confers tolerance to herbicides containing glufosinate-ammonium. Pullets (20 wk of age) were placed in cage lots (3 hens/cage, 2 cages/lot) and were randomly assigned to 1 of 3 corn-soybean meal dietary treatments (12 lots/treatment) formulated with the following maize grains: near-isogenic control (control), conventional maize, and transgenic test corn line 59122 containing event DAS-59122-7. Differences between 59122 and control group means were evaluated with statistical significance at P < 0.05. Body weight and gain, egg production, egg mass, and feed efficiency for hens fed the 59122 corn were not significantly different from the respective values for hens fed diets formulated with control maize grain. Egg component weights, Haugh unit measures, and egg weight class distribution were similar regardless of the corn source. This research indicates that performance of hens fed diets containing 59122 maize grain, as measured by egg production and egg quality, was similar to that of hens fed diets formulated with near-isogenic corn grain.

Physicochemical composition and glycemic index of whole grain bread produced from composite flours of quality protein maize and wheat

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C. T. Akanbi

2016-01-01

Full Text Available This study entails quality assessment of whole grain bread produced from composite flours of quality protein maize and wheat. Quality protein maize and wheat were processed into flours and mixed at various ratios for bread production. The proximate compositions, physical properties, glycemic response, functional and sensory properties of the samples were evaluated using standard methods. The result showed no significant difference (p<0.05 in the proximate composition parameters of the bread samples. The loaf height (2.50 - 3.95 cm, volume (291.00 - 415.00 cm3 and specific volume(1.72 - 2.42 cm3/g decreased significantly with increasing level of quality protein maize, however, loaf length was not affected by the substitution of quality protein maize. The result of the functional properties showed that final viscosity, water absorption and swelling capacity increased with increasing level of quality protein maize. The result of the glycemic response showed that the inclusion of quality protein maize resulted in decline in the blood glucose content (glycemic index of the products. The bread samples were generally acceptable however; bread with 100% wheat was the most preferred. The result of the sensory properties showed that there was significant difference (p<0.05 in the texture and taste of 100% wheat bread and the other samples. The study concluded that substitution of quality protein maize with wheat produced acceptable whole grain loaves that have positive effect on the reduction of blood glucose level.

A review on important maize diseases and their management in Nepal

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Subash Subedi

2015-12-01

Full Text Available In Nepal, maize ranks second after rice both in area and production. In recent years, maize area and production has shown a steady increase, but productivity has been low (2.46 t/ha. The major maize producing regions in Nepal are mid hill (72.85%, terai (17.36% and high hill (9.79% respectively. A literature review was carried out to explore major maize diseases and their management in Nepal. The omnipresent incidence of diseases at the pre harvest stage has been an important bottleneck in increasing production. Till now, a total of 78 (75 fungal and 3 bacterial species are pathogenic to maize crop in Nepal. The major and economically important maize diseases reported are Gray leaf spot, Northern leaf blight, Southern leaf Blight, Banded leaf and sheath blight, Ear rot, Stalk rot, Head smut, Common rust, Downy mildew and Brown spot. Information on bacterial and virus diseases, nematodes and yield loss assessment is also given. Description of the major maize diseases, their causal organisms, distribution, time and intensity of disease incidence, symptoms, survival, spreads, environmental factors for disease development, yield losses and various disease management strategies corresponded to important maize diseases of Nepal are gathered and compiled thoroughly from the available publications. Concerted efforts of NARC commodity programs, divisions, ARS and RARS involving research on maize pathology and their important outcomes are mentioned. The use of disease management methods focused on host resistance has also been highlighted.

Gibberellin-induced changes in the populations of translatable mRNAs and accumulated polypeptides in dwarfs of maize and pea

International Nuclear Information System (INIS)

Chory, J.; Voytas, D.F.; Olszewski, N.E.; Ausubel, F.M.

1987-01-01

Two-dimensional gel electrophoresis was used to characterize the molecular mechanism of gibberellin-induced stem elongation in maize and pea. Dwarf mutants of maize and pea lack endogenous gibberellin (GA 1 ) but become phenotypically normal with exogenous applications of this hormone. Sections from either etiolated maize or green pea seedlings were incubated in the presence of [ 35 S] methionine for 3 hours with or without gibberellin. Labeled proteins from soluble and particulate fractions were analyzed by two-dimensional gel electrophoresis and specific changes in the patterns of protein synthesis were observed upon treatment with gibberellin. Polyadenylated mRNAs from etiolated or green maize shoots and green pea epicotyls treated or not with gibberellin (a 0.5 to 16 hour time course) were assayed by translation in a rabbit reticulocyte extract and separation of products by two-dimensional gel electrophoresis. Both increases and decreases in the levels of specific polypeptides were seen for pea and corn, and these changes were observed within 30 minutes of treatment with gibberellin. Together, these data indicate that gibberellin induces changes in the expression of a subset of gene products within elongating dwarfs. This may be due to changes in transcription rate, mRNA stability, or increased efficiency of translation of certain mRNAs

High-specificity detection of rare alleles with Paired-End Low Error Sequencing (PELE-Seq).

Science.gov (United States)

Preston, Jessica L; Royall, Ariel E; Randel, Melissa A; Sikkink, Kristin L; Phillips, Patrick C; Johnson, Eric A

2016-06-14

Polymorphic loci exist throughout the genomes of a population and provide the raw genetic material needed for a species to adapt to changes in the environment. The minor allele frequencies of rare Single Nucleotide Polymorphisms (SNPs) within a population have been difficult to track with Next-Generation Sequencing (NGS), due to the high error rate of standard methods such as Illumina sequencing. We have developed a wet-lab protocol and variant-calling method that identifies both sequencing and PCR errors, called Paired-End Low Error Sequencing (PELE-Seq). To test the specificity and sensitivity of the PELE-Seq method, we sequenced control E. coli DNA libraries containing known rare alleles present at frequencies ranging from 0.2-0.4 % of the total reads. PELE-Seq had higher specificity and sensitivity than standard libraries. We then used PELE-Seq to characterize rare alleles in a Caenorhabditis remanei nematode worm population before and after laboratory adaptation, and found that minor and rare alleles can undergo large changes in frequency during lab-adaptation. We have developed a method of rare allele detection that mitigates both sequencing and PCR errors, called PELE-Seq. PELE-Seq was evaluated using control E. coli populations and was then used to compare a wild C. remanei population to a lab-adapted population. The PELE-Seq method is ideal for investigating the dynamics of rare alleles in a broad range of reduced-representation sequencing methods, including targeted amplicon sequencing, RAD-Seq, ddRAD, and GBS. PELE-Seq is also well-suited for whole genome sequencing of mitochondria and viruses, and for high-throughput rare mutation screens.

Field-Evolved Resistance to Bt Maize by Western Corn Rootworm

Science.gov (United States)

Gassmann, Aaron J.; Petzold-Maxwell, Jennifer L.; Keweshan, Ryan S.; Dunbar, Mike W.

2011-01-01

Background Crops engineered to produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt) are planted on millions of hectares annually, reducing the use of conventional insecticides and suppressing pests. However, the evolution of resistance could cut short these benefits. A primary pest targeted by Bt maize in the United States is the western corn rootworm Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Methodology/Principal Findings We report that fields identified by farmers as having severe rootworm feeding injury to Bt maize contained populations of western corn rootworm that displayed significantly higher survival on Cry3Bb1 maize in laboratory bioassays than did western corn rootworm from fields not associated with such feeding injury. In all cases, fields experiencing severe rootworm feeding contained Cry3Bb1 maize. Interviews with farmers indicated that Cry3Bb1 maize had been grown in those fields for at least three consecutive years. There was a significant positive correlation between the number of years Cry3Bb1 maize had been grown in a field and the survival of rootworm populations on Cry3Bb1 maize in bioassays. However, there was no significant correlation among populations for survival on Cry34/35Ab1 maize and Cry3Bb1 maize, suggesting a lack of cross resistance between these Bt toxins. Conclusions/Significance This is the first report of field-evolved resistance to a Bt toxin by the western corn rootworm and by any species of Coleoptera. Insufficient planting of refuges and non-recessive inheritance of resistance may have contributed to resistance. These results suggest that improvements in resistance management and a more integrated approach to the use of Bt crops may be necessary. PMID:21829470

Sequence specific motor performance gains after memory consolidation in children and adolescents.

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Shoshi Dorfberger

Full Text Available Memory consolidation for a trained sequence of finger opposition movements, in 9- and 12-year-old children, was recently found to be significantly less susceptible to interference by a subsequent training experience, compared to that of 17-year-olds. It was suggested that, in children, the experience of training on any sequence of finger movements may affect the performance of the sequence elements, component movements, rather than the sequence as a unit; the latter has been implicated in the learning of the task by adults. This hypothesis implied a possible childhood advantage in the ability to transfer the gains from a trained to the reversed, untrained, sequence of movements. Here we report the results of transfer tests undertaken to test this proposal in 9-, 12-, and 17-year-olds after training in the finger-to-thumb opposition sequence (FOS learning task. Our results show that the performance gains in the trained sequence partially transferred from the left, trained hand, to the untrained hand at 48-hours after a single training session in the three age-groups tested. However, there was very little transfer of the gains from the trained to the untrained, reversed, sequence performed by either hand. The results indicate sequence specific post-training gains in FOS performance, as opposed to a general improvement in performance of the individual, component, movements that comprised both the trained and untrained sequences. These results do not support the proposal that the reduced susceptibility to interference, in children before adolescence, reflects a difference in movement syntax representation after training.

Sequence specific motor performance gains after memory consolidation in children and adolescents.

Science.gov (United States)

Dorfberger, Shoshi; Adi-Japha, Esther; Karni, Avi

2012-01-01

Memory consolidation for a trained sequence of finger opposition movements, in 9- and 12-year-old children, was recently found to be significantly less susceptible to interference by a subsequent training experience, compared to that of 17-year-olds. It was suggested that, in children, the experience of training on any sequence of finger movements may affect the performance of the sequence elements, component movements, rather than the sequence as a unit; the latter has been implicated in the learning of the task by adults. This hypothesis implied a possible childhood advantage in the ability to transfer the gains from a trained to the reversed, untrained, sequence of movements. Here we report the results of transfer tests undertaken to test this proposal in 9-, 12-, and 17-year-olds after training in the finger-to-thumb opposition sequence (FOS) learning task. Our results show that the performance gains in the trained sequence partially transferred from the left, trained hand, to the untrained hand at 48-hours after a single training session in the three age-groups tested. However, there was very little transfer of the gains from the trained to the untrained, reversed, sequence performed by either hand. The results indicate sequence specific post-training gains in FOS performance, as opposed to a general improvement in performance of the individual, component, movements that comprised both the trained and untrained sequences. These results do not support the proposal that the reduced susceptibility to interference, in children before adolescence, reflects a difference in movement syntax representation after training.

Diversity in global maize germplasm: Characterization and utilization

Indian Academy of Sciences (India)

2012-10-15

Oct 15, 2012 ... maize farmers as well as to the scientific community are depicted in figure 1, and ..... best practices for maintaining the original genetic diversity of the gene bank ..... maize; in Studies in the neolithic and urban revolution: V.

Climate Change and Maize Production: Empirical Evidence from ...

African Journals Online (AJOL)

Michael Madukwe

Time series data on aggregate maize production, fertilizer use, .... The maize response model (eqn 3) was estimated using the time series data for ... The R. 2 value obtained from the equation is 0.534. This further indicates that aggregate total.

Response of archaeal communities in the rhizosphere of maize and soybean to elevated atmospheric CO2 concentrations.

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David M Nelson

Full Text Available BACKGROUND: Archaea are important to the carbon and nitrogen cycles, but it remains uncertain how rising atmospheric carbon dioxide concentrations ([CO(2] will influence the structure and function of soil archaeal communities. METHODOLOGY/PRINCIPAL FINDINGS: We measured abundances of archaeal and bacterial 16S rRNA and amoA genes, phylogenies of archaeal 16S rRNA and amoA genes, concentrations of KCl-extractable soil ammonium and nitrite, and potential ammonia oxidation rates in rhizosphere soil samples from maize and soybean exposed to ambient (∼385 ppm and elevated (550 ppm [CO(2] in a replicated and field-based study. There was no influence of elevated [CO(2] on copy numbers of archaeal or bacterial 16S rRNA or amoA genes, archaeal community composition, KCl-extractable soil ammonium or nitrite, or potential ammonia oxidation rates for samples from maize, a model C(4 plant. Phylogenetic evidence indicated decreased relative abundance of crenarchaeal sequences in the rhizosphere of soybean, a model leguminous-C(3 plant, at elevated [CO(2], whereas quantitative PCR data indicated no changes in the absolute abundance of archaea. There were no changes in potential ammonia oxidation rates at elevated [CO(2] for soybean. Ammonia oxidation rates were lower in the rhizosphere of maize than soybean, likely because of lower soil pH and/or abundance of archaea. KCl-extractable ammonium and nitrite concentrations were lower at elevated than ambient [CO(2] for soybean. CONCLUSION: Plant-driven shifts in soil biogeochemical processes in response to elevated [CO(2] affected archaeal community composition, but not copy numbers of archaeal genes, in the rhizosphere of soybean. The lack of a treatment effect for maize is consistent with the fact that the photosynthesis and productivity of maize are not stimulated by elevated [CO(2] in the absence of drought.

29 CFR 1926.752 - Site layout, site-specific erection plan and construction sequence.

Science.gov (United States)

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Site layout, site-specific erection plan and construction... Steel Erection § 1926.752 Site layout, site-specific erection plan and construction sequence. (a... strength or sufficient strength to support the loads imposed during steel erection. (c) Site layout. The...

Genomic features shaping the landscape of meiotic double-strand-break hotspots in maize.

Science.gov (United States)

He, Yan; Wang, Minghui; Dukowic-Schulze, Stefanie; Zhou, Adele; Tiang, Choon-Lin; Shilo, Shay; Sidhu, Gaganpreet K; Eichten, Steven; Bradbury, Peter; Springer, Nathan M; Buckler, Edward S; Levy, Avraham A; Sun, Qi; Pillardy, Jaroslaw; Kianian, Penny M A; Kianian, Shahryar F; Chen, Changbin; Pawlowski, Wojciech P

2017-11-14

Meiotic recombination is the most important source of genetic variation in higher eukaryotes. It is initiated by formation of double-strand breaks (DSBs) in chromosomal DNA in early meiotic prophase. The DSBs are subsequently repaired, resulting in crossovers (COs) and noncrossovers (NCOs). Recombination events are not distributed evenly along chromosomes but cluster at recombination hotspots. How specific sites become hotspots is poorly understood. Studies in yeast and mammals linked initiation of meiotic recombination to active chromatin features present upstream from genes, such as absence of nucleosomes and presence of trimethylation of lysine 4 in histone H3 (H3K4me3). Core recombination components are conserved among eukaryotes, but it is unclear whether this conservation results in universal characteristics of recombination landscapes shared by a wide range of species. To address this question, we mapped meiotic DSBs in maize, a higher eukaryote with a large genome that is rich in repetitive DNA. We found DSBs in maize to be frequent in all chromosome regions, including sites lacking COs, such as centromeres and pericentromeric regions. Furthermore, most DSBs are formed in repetitive DNA, predominantly Gypsy retrotransposons, and only one-quarter of DSB hotspots are near genes. Genic and nongenic hotspots differ in several characteristics, and only genic DSBs contribute to crossover formation. Maize hotspots overlap regions of low nucleosome occupancy but show only limited association with H3K4me3 sites. Overall, maize DSB hotspots exhibit distribution patterns and characteristics not reported previously in other species. Understanding recombination patterns in maize will shed light on mechanisms affecting dynamics of the plant genome.

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 1005.10...

The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

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Renata Calixto Campos

Full Text Available Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h, a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

The Importance of Maize Management on Dung Beetle Communities in Atlantic Forest Fragments.

Science.gov (United States)

Campos, Renata Calixto; Hernández, Malva Isabel Medina

2015-01-01

Dung beetle community structures changes due to the effects of destruction, fragmentation, isolation and decrease in tropical forest area, and therefore are considered ecological indicators. In order to assess the influence of type of maize cultivated and associated maize management on dung beetle communities in Atlantic Forest fragments surrounded by conventional and transgenic maize were evaluated 40 Atlantic Forest fragments of different sizes, 20 surrounded by GM maize and 20 surrounded by conventional maize, in February 2013 and 2014 in Southern Brazil. After applying a sampling protocol in each fragment (10 pitfall traps baited with human feces or carrion exposed for 48 h), a total of 3454 individuals from 44 species were captured: 1142 individuals from 38 species in GM maize surrounded fragments, and 2312 from 42 species in conventional maize surrounded fragments. Differences in dung beetle communities were found between GM and conventional maize communities. As expected for fragmented areas, the covariance analysis showed a greater species richness in larger fragments under both conditions; however species richness was greater in fragments surrounded by conventional maize. Dung beetle structure in the forest fragments was explained by environmental variables, fragment area, spatial distance and also type of maize (transgenic or conventional) associated with maize management techniques. In Southern Brazil's scenario, the use of GM maize combined with associated agricultural management may be accelerating the loss of diversity in Atlantic Forest areas, and consequently, important ecosystem services provided by dung beetles may be lost.

Isolation and characterization of subgenomic DNAs encapsidated in 'single' T = 1 isometric particles of Maize streak virus

International Nuclear Information System (INIS)

Casado, Carolina G.; Javier Ortiz, G.; Padron, Eric; Bean, Samantha J.; McKenna, Robert; Agbandje-McKenna, Mavis; Boulton, Margaret I.

2004-01-01

'Single' T = 1 isometric particles of Maize streak virus (MSV) have been isolated from infected maize leaves. Biochemical and genetic characterizations show that these particles contain subgenomic (sg) MSV DNA encapsidated by the MSV coat protein. The largest sg DNA is 1.56 kb, slightly larger than half genome size, although sg DNAs as small as 0.2 kb were also cloned. The sg DNAs are not infectious, and they do not appear to play a role in the pathogenicity of MSV. This is the first report of sg DNAs for MSV and, to our knowledge, the first time that encapsidated sg DNAs have been characterized at the sequence level for any geminivirus. These data will assist in our investigations into the role of genomic DNA in the formation of the unique geminate capsid architecture of the Geminiviridae

Meiotic transmission of an in vitro-assembled autonomous maize minichromosome.

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Shawn R Carlson

2007-10-01

Full Text Available Autonomous chromosomes are generated in yeast (yeast artificial chromosomes and human fibrosarcoma cells (human artificial chromosomes by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes. As a step toward improving transgenic crop production, we report the development of autonomous maize minichromosomes (MMCs. We constructed circular MMCs by combining DsRed and nptII marker genes with 7-190 kb of genomic maize DNA fragments containing satellites, retroelements, and/or other repeats commonly found in centromeres and using particle bombardment to deliver these constructs into embryogenic maize tissue. We selected transformed cells, regenerated plants, and propagated their progeny for multiple generations in the absence of selection. Fluorescent in situ hybridization and segregation analysis demonstrated that autonomous MMCs can be mitotically and meiotically maintained. The MMC described here showed meiotic segregation ratios approaching Mendelian inheritance: 93% transmission as a disome (100% expected, 39% transmission as a monosome crossed to wild type (50% expected, and 59% transmission in self crosses (75% expected. The fluorescent DsRed reporter gene on the MMC was expressed through four generations, and Southern blot analysis indicated the encoded genes were intact. This novel approach for plant transformation can facilitate crop biotechnology by (i combining several trait genes on a single DNA fragment, (ii arranging genes in a defined

Molecular Evolution and Genetic Variation of G2-Like Transcription Factor Genes in Maize.

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Fang Liu

Full Text Available The productivity of maize (Zea mays L. depends on the development of chloroplasts, and G2-like transcription factors play a central role in regulating chloroplast development. In this study, we identified 59 G2-like genes in the B73 maize genome and systematically analyzed these genes at the molecular and evolutionary levels. Based on gene structure character, motif compositions and phylogenetic analysis, maize G2-like genes (ZmG1- ZmG59 were divided into seven groups (I-VII. By synteny analysis, 18 collinear gene pairs and strongly conserved microsyntny among regions hosting G2-like genes across maize and sorghum were found. Here, we showed that the vast majority of ZmG gene duplications resulted from whole genome duplication events rather than tandem duplications. After gene duplication events, some ZmG genes were silenced. The functions of G2-like genes were multifarious and most genes that are expressed in green tissues may relate to maize photosynthesis. The qRT-PCR showed that the expression of these genes was sensitive to low temperature and drought. Furthermore, we analyzed differences of ZmGs specific to cultivars in temperate and tropical regions at the population level. Interestingly, the single nucleotide polymorphism (SNP analysis revealed that nucleotide polymorphism associated with different temperature zones. Above all, G2-like genes were highly conserved during evolution, but polymorphism could be caused due to a different geographical location. Moreover, G2-like genes might be related to cold and drought stresses.