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PubMed1990

A transcript identified by MuA of maize is associated with Mutator activity.

A Mu element, which we designated MuA, was cloned from a maize line with a Mutator background by its homology to the terminal inverted repeats of Mu1. Like other Mu elements, MuA has terminal inverted repeats of approximately 200 bp which are homologous to those of Mu1, but the internal region is different. MuA is unique in several aspects, being approximately 5.5 kb in size and the largest Mu element reported to date. It is flanked by 8 bp duplications instead of the 9 bp duplications found in most other Mu insertions. The internal sequences of MuA hybridize to restriction fragments that cosegregate with Mutator activity in maize lines showing 1:1 segregation for somatic mutability. The most interesting observation is that a transcript of approximately 3.5 kb identified by the internal sequences of MuA is both qualitatively and quantitatively associated with Mutator activity. This transcript is present in maize lines containing germinal Mutator activity but is undetectable in maize inbreds with no known Mutator activity. The amount of the transcript is decreased in lines that have lost germinal Mutator activity. Northern analysis of maize a1-Mum mutant lines that segregate 1:1 for mutability shows that a transcript of the same size is associated with somatic Mutator activity. These data suggest that the 3.5 kb transcript is produced by the autonomous element that confers both germinal and somatic Mutator activity. The possibility that MuA is an autonomous or regulator element of the Mu family is discussed.

Blotting, Northern↗

PubMed1992

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

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

Blotting, Northern↗

PubMed1995

Expression of a cytochrome P450 gene family in maize.

Maize seedlings, like seedlings of many other plants, are rich in cytochrome P450 (P450) enzyme activity. Four P450 genes (CYPzm1-4), isolated from a seedling-specific cDNA library, are characterized by a transient and seedling-specific expression pattern. The maximum steady state mRNA levels are reached at 3 days in root and at 7 days in shoot tissue, respectively. All four genes belong to one gene family and are closely related to the CYP71 family of plant P450 genes, which includes the enzymes of the ripening avocado fruit (CYP71A1) and eggplant hypocotyls (CYP71A2, A3, A4). The expression of these related P450 genes in monocot and dicot plants indicates that these enzymes play a significant role in plants; however, the in vivo enzyme functions are unknown. The divergence of the four members of the maize gene family is sufficiently high to account for different substrate and/or reaction specificity. Although the general expression pattern of the four genes is identical, the maximum steady-state mRNA levels vary in different maize lines. In situ hybridisation reveals the highest mRNA levels in the coleoptile, the first developed leaflets, the ground tissue of the nodular complex, and in the cortex and pith of the region of cell division in the root. The mapping of the maize CYPzm genes shows that, as in animals, P450 genes of the same family can be clustered. The presence of the CYPzm gene cluster in maize argues for generation of distinct plant P450 gene families by gene duplication.

Amino Acid Sequence↗

PubMed1976

Genetically defined peptidases of maize. I. Biochemical characterization of allelic and nonallelic forms.

A number of biochemical properties have been investigated for both allelic and nonallelic forms of maize peptidases. Four aminopeptidases exist in maize (LAP-A, LAP-B, LAP-C, and LAP-D) and are the products of four diallelic loci. The aminopeptidases fall into two biochemical groups on the basis of these studies. LAP-A and LAP-D have comparatively low apparent Km (Kapp) values for arginine-naphthylamide derivatives and high velocities for arginine-naphthyl-amide and lysine-naphthylamide. LAP-B and LAP-C, on the other hand, have lower Kapp values for leucine-naphthylamide and higher velocities for nonpolar amino acid-naphthylamides than for arginine-naphthylamide. LAP-A and LAP-D are also relatively more heat stable than LAP-B and LAP-C and have somewhat higher molecular weights (71,500) than LAP-B and LAP-C (63,500). In determining molecular weights of the peptidases, use was made of their differential substrate specificities toward amino acid-naphthylamides. Some properties of genetically defined maize endopeptidase are also presented. Maize endopeptidase is inhibited by the sulfhydryl reagents N-ethylmaleimide and p-chloromercuribenzoate (pCMB), and by tosyl lysine chloromethyl ketone, Maize aminopeptidase activity is inhibited by N-ethylmaleimide, pCMB, and EDTA (ethylenediamine tetraacetic acid).

Alleles↗

PubMed1995

DNA sequence analysis of a cyclophilin gene from maize: developmental expression and regulation by salicylic acid.

In plants, such as maize, cyclophilin (Cyp) genes are expressed at a basal level in all tissues. Amounts of Cyp mRNA above the basic level are observed in germinating seedlings, in growing tissues/organs such as roots and leaf meristematic tissue of young maize plants, nodes and embryonic female inflorescences of adult plants and also in non-proliferating tissues such as the internodes of adult plants. Salicylic acid (SA) enhances the transcription of maize Cyp genes. The possible involvement of SA in the pathway leading to defense responses induced by abiotic stresses such as mercuric chloride treatment is discussed. A maize Cyp genomic clone isolated using a maize Cyp cDNA probe contains 737 bp of the 5' upstream and the entire coding region. This Cyp gene is not interrupted by intervening sequences. In the 5' upstream region, characteristic transcription signals as well as putative regulatory sequences were identified. Two TATA boxes are found at positions -56 bp and -66 bp with respect to the transcription start site. Two putative heat shock elements were identified in the promoter region; a metal regulatory element and a third heat shock element were localized in the 5' untranslated leader. Several putative polyadenylation signals and (G)T-rich sequence motifs were identified in the 3' untranslated region.

Amino Acid Isomerases↗

PubMed1993

Niacin, thiamin, and pantothenic acid bioavailability to humans from maize bran as affected by milling and particle size.

The objective of the project was to determine the bioavailability of selected B vitamins (niacin, pantothenic acid and thiamin) to humans from wet and dry milled maize brans which were coarsely or finely ground. Using a double cross-over design, the nine subjects were fed laboratory controlled diets containing unsupplemented bread or bread supplemented with finely ground, wet milled maize bran; coarsely ground, wet milled maize bran; finely ground, dry milled corn bran; or coarsely ground, dry milled maize bran. Subjects made complete collections of urine throughout the study which were analyzed for contents of the test vitamins. Although varying somewhat among vitamins, in general, better apparent bioavailability was achieved with the finely ground, dry milled maize bran than with the other test brans.

Adult↗

PubMed1995

The nutritive quality of maize-soybean (70:30) tempe flour.

The nutritive quality of maize-soybean (70:30) tempe flour manufactured by fermentation with Rhizopus oligosporus: Rhizopus orysae (1:1) was determined using weanling rats. Mould fermentation of maize-soybean mixture did not significantly affect its proximate composition. It increased the content of reducing sugars, total acids and aminonitrogen by about 43, 195 and 482 percent, respectively, and decreased phytate content by 46 percent. In vitro iron absorption for maize flour and maize-soybean tempe flour was 2.46 and 5.51 percent, respectively. Protein Efficiency Ratio (PER) and Net Protein Ratio (NPR) for maize-soybean tempe flour and skim-milk diets were 2.71 and 2.96, respectively, for PER, and 3.31 and 3.51, respectively, for NPR. In vivo protein digestibility of the two products was 95.0 and 98.0 percent, respectively.

Animals↗

PubMed1995

Fertility of Fusarium moniliforme from maize and sorghum related to fumonisin production in Italy.

Forty-three strains of Fusarium moniliforme isolated from infected maize and sorghum plants in Italy were assayed for their ability to produce fertile crosses with "A" and "F" mating population tester strains, in relation to their ability to produce fumonisins on maize substrate. Most of the strains isolated from maize (ear and stalk rot and maize-based feed), producing fumonisin B1 (FB1) and B2 (FB2) (up to 4,100 and 855 mg/kg, respectively), belonged to the "A" mating population. All of the strains isolated from sorghum belonged to the "F" mating population and produced little or no FB1 and FB2. This is the first report of the occurrence of mating population "F" in Europe. Our data on strains from Italy are consistent with previous studies from the United States that found significant differences in sexual fertility and fumonisin production between strains from maize and sorghum.

Crosses, Genetic↗

PubMed1992

Differences between the anticoccidial potencies of monensin in maize-based or wheat-based chicken diets.

Experiments were carried out to investigate why the anticoccidial ionophore monensin is more potent against the coccidium Eimeria tenella in chickens fed on a maize-based diet (as in the USA) than in chickens fed on a wheat-based diet (as in the UK). The explanation seems to be that the pathogenicity of E. tenella is lower in maize-fed chickens than in wheat-fed chickens, whether monensin is present in the diet or not. Possible reasons for this are suggested. The better survival of maize-fed birds may be partly due to protective effects of the higher concentrations of vitamins A and E derived from their diet. Furthermore, the higher concentrations of niacin and riboflavin in wheat than in maize may enhance coccidial pathogenicity. These opposing factors might combine to cause equivalent infection levels to produce more severe coccidiosis in chickens fed on a wheat-based diet than on a maize-based diet.

Animal Feed↗

PubMed1996

Binding sites for maize nuclear proteins in the subterminal regions of the transposable element Activator.

Genetic data suggest that transposition of the maize element Activator (Ac) is modulated by host factors. Using gel retardation and DNase I protection assays we identified maize proteins which bind to seven subterminal sites in both ends of Ac. Four DNase I-protected sites contain a GGTAAA sequence, the other three include either GATAAA or GTTAAA. The specificity of the maize protein binding to Ac was verified by using a synthetic fragment containing four GGTAAA motifs as probe and competitor in gel retardation assays. All seven binding sites are located within regions required in cis for transposition. A maize protein binding site with the same sequence has previously been identified in the terminal inverted repeats of the maize Mutator element. Thus, the protein, that recognizes this sequence is a good candidate for a regulatory host factor for Ac transposition.

Base Sequence↗

PubMed2002

Maize introduction into Europe: the history reviewed in the light of molecular data.

The resolution that can be obtained from molecular genetic markers affords new prospects for understanding the dispersion of agricultural species from their primary origin centres. In order to study the introduction and the dispersion of maize in Europe, we have characterised a large and representative set of maize populations of both American and European origins for their variation at 29 restriction fragment length polymorphism loci. Polymorphism was higher for American populations than for European populations (respectively, 12.3 and 9.6 alleles per locus, on average), and only a few alleles were specific to European populations. Investigation of genetic similarity between populations from both continents made it possible to identify various types of American maize introduced into Europe at different times or in different places and which have given rise to distinctive European races. Beyond confirming the importance of Caribbean germplasm, the first maize type to be introduced into Europe, this research revealed that introductions of Northern American flint populations have played a key role in the adaptation of maize to the European climate. According to a detailed historical investigation, the introduction of these populations must have occurred shortly after the discovery of the New World.

Europe↗

PubMed2003

QTL and candidate genes phytoene synthase and zeta-carotene desaturase associated with the accumulation of carotenoids in maize.

Carotenoids are a class of fat-soluble antioxidant vitamin compounds present in maize ( Zea mays L.) that may provide health benefits to animals or humans. Four carotenoid compounds are predominant in maize grain: beta-carotene, beta-cryptoxanthin, zeaxanthin, and lutein. Although beta-carotene has the highest pro-vitamin A activity, it is present in a relatively low concentration in maize kernels. We set out to identify quantitative trait loci (QTL) affecting carotenoid accumulation in maize kernels. Two sets of segregating families were evaluated-a set of F2:3 lines derived from a cross of W64a x A632, and their testcross progeny with AE335. Molecular markers were evaluated on the F2:3 lines and a genetic linkage map created. High-performance liquid chromatography was performed to measure beta-carotene, beta-cryptoxanthin, zeaxanthin, and lutein on both sets of materials. Composite interval mapping identified chromosome regions with QTL for one or more individual carotenoids in the per se and testcross progenies. Notably QTL in the per se population map to regions with candidate genes, yellow 1 and viviparous 9, which may be responsible for quantitative variation in carotenoids. The yellow 1 gene maps to chromosome six and is associated with phytoene synthase, the enzyme catalyzing the first dedicated step in the carotenoid biosynthetic pathway. The viviparous 9 gene maps to chromosome seven and is associated with zeta-carotene desaturase, an enzyme catalyzing an early step in the carotenoid biosynthetic pathway. If the QTL identified in this study are confirmed, particularly those associated with candidates genes, they could be used in an efficient marker-assisted selection program to facilitate increasing levels of carotenoids in maize grain.

Alkyl and Aryl Transferases↗

PubMed2004

The Rxo1/ Rba1 locus of maize controls resistance reactions to pathogenic and non-host bacteria.

Infiltration of different maize lines with a variety of bacterial pathogens of maize, rice and sorghum identified qualitative differences in resistant reactions. Isolates from two bacterial species induced rapid hypersensitive reactions (HR) in some maize lines, but not others. All isolates of the non-host pathogen Xanthomonas oryzae pv. oryzicola (bacterial leaf streak disease of rice) and some isolates of the pathogenic bacterium Burkholderia andropogonis induced HR when infiltrated into maize line B73, but not Mo17. Genetic control of the HR to both bacteria segregated as a single dominant gene. Surprisingly, both phenotypes mapped to the same locus, indicating they are either tightly linked or controlled by the same gene. The locus maps on the short arm of maize chromosome six near several other disease-resistance genes. Results indicate the same type of genes may contribute to both non-host resistance and resistance to pathogens.

Blotting, Northern↗

PubMed2005

Genetic mapping of maize stripe disease resistance from the Mascarene source.

Maize stripe virus (MStV) is a potentially threatening virus disease of maize in the tropics. We mapped quantitative trait loci (QTLs) controlling resistance to MStV in a maize population of 157 F(2:3) families derived from the cross between two maize lines, Rev81 (tropical resistant) and B73 (temperate susceptible). Resistance was evaluated under artificial inoculations in replicated screenhouse trials across different seasons in Réunion Island, France. Composite interval mapping was employed for QTL detection with a linkage map of 143 microsatellite markers. Heritability estimates across seasons were 0.96 and 0.90 for incidence and severity, respectively, demonstrating a high genotypic variability and a good control of the environment. Three regions on chromosomes 2L, 3 and 5, with major effects, and another region on chromosome 2S, with minor effects, provided resistance to MStV in Rev81. In individual seasons, the chr2L QTL explained 60-65% of the phenotypic variation for disease incidence and 21-42% for severity. The chr3 QTL, mainly associated with incidence and located near centromere, explained 42-57% of the phenotypic variation, whereas the chr5 QTL, mainly associated with severity, explained 26-53%. Overall, these QTLs explained 68-73% of the phenotypic variance for incidence and 50-59% for severity. The major QTLs on chr2 and 3 showed additive gene action and were found to be stable over time and across seasons. They also were found to be included in genomic regions with important clusters of resistance genes to diseases and pests. The major QTL on chr5 appeared to be partially dominant in favour of resistance. It was stable over time but showed highly significant QTL x season interactions. Possible implications of these QTLs in different mechanisms of resistance against the virus or the insect vector are discussed. The prospects for transferring these QTLs in susceptible maize cultivars and combining them with other resistances to virus diseases by conventional or marker-assisted breeding are promising.

Chromosome Mapping↗

PubMed2004

Land evaluation for maize based on fuzzy set and interpolation.

The objective of this article is to apply fuzzy set and interpolation techniques for land suitability evaluation for maize in Northern Ghana. Land suitability indices were computed at point observations using the Semantic Import (SI) model, whereas spatial interpolation was carried out by block kriging. Interpolated land suitability shows a high correlation (R2 = 0.87) with observed maize yield at the village level. This indicates that land suitability is closely related to maize yield in the study area. Membership functions were further used to assess the degree of limitation of land characteristics to maize. Sixty percent of the data has membership functions ranging from 0.23 for ECEC to 1.00 for drainage. ECEC, organic C, and clay are the major constraints to maize yield. The use of the fuzzy technique is helpful for land suitability evaluation, especially in applications in which subtle differences in soil quality are of a major interest. Furthermore, the use of kriging that exploits spatial variability of data is useful in producing continuous land suitability maps and in estimating uncertainties associated with predicted land suitability indices.

Agriculture↗

PubMed2006

Nitric oxide enhances salt tolerance in maize seedlings through increasing activities of proton-pump and Na+/H+ antiport in the tonoplast.

Nitric oxide (NO), an endogenous signaling molecule in animals and plants, mediates responses to abiotic and biotic stresses. Our previous work demonstrated that 100 microM sodium nitroprusside (SNP, an NO donor) treatment of maize seedlings increased K(+) accumulation in roots, leaves and sheathes, while decreasing Na(+) accumulation (Zhang et al. in J Plant Physiol Mol Biol 30:455-459, 2004b). Here we investigate how NO regulates Na(+), K(+) ion homeostasis in maize. Pre-treatment with 100 muM SNP for 2 days improved later growth of maize plants under 100 mM NaCl stress, as indicated by increased dry matter accumulation, increased chlorophyll content, and decreased membrane leakage from leaf cells. An NO scavenger, methylene blue (MB-1), blocked the effect of SNP. These results indicated that SNP-derived NO enhanced maize tolerance to salt stress. Further analysis showed that NaCl induced a transient increase in the NO level in maize leaves. Both NO and NaCl treatment stimulated vacuolar H(+)-ATPase and H(+)-PPase activities, resulting in increased H(+)-translocation and Na(+)/H(+) exchange. NaCl-induced H(+)-ATPase and H(+)-PPase activities were diminished by MB-1. 1-Butanol, an inhibitor of phosphatidic acid (PA) production by phospholipase D (PLD), reduced NaCl- and NO-induced H(+)-ATPase activation. In contrast, applied PA stimulated H(+)-ATPase activity. These results suggest that NO acts as a signal molecule in the NaCl response by increasing the activities of vacuolar H(+)-ATPase and H(+)-PPase, which provide the driving force for Na(+)/H(+) exchange. PLD and PA play an important role in this process.

Cell Membrane↗

PubMed2026

Holistic approaches for improvement of maize resistance against lodging stress: current status and future perspective.

Lodging is a major constraint in maize production, causing significant yield losses, reduced grain quality, and harvesting inefficiencies, thereby posing a serious challenge to global food security and climate-resilient agriculture. This review synthesizes current knowledge on the genetic, physiological, and agronomic determinants of maize lodging resistance and evaluates holistic strategies for improving tolerance to lodging stress. Recent advances in quantitative trait locus (QTL) mapping, genome-wide association studies (GWAS), functional gene characterization, genome editing, high-throughput phenotyping, and precision agronomy have provided powerful tools to enhance stalk biomechanics, root anchorage, and adaptive plant architecture. Integrating genomic discovery with advanced phenomics and optimized agronomic management offers a scalable framework for accelerating the development of high-yielding, lodging-resilient maize cultivars. However, critical gaps remain in understanding the genetic coordination between stalk strength and root system architecture, integrating multi-omics approaches to unravel regulatory networks, validating genome-editing interventions across diverse agro-ecologies, and developing environment-responsive predictive breeding models and cost-effective phenotyping tools, particularly for stress-prone regions. Addressing these challenges through coordinated multi-environment trials and integrative molecular-agronomic strategies will facilitate the translation of genomic discoveries into climate-resilient, high-performing maize cultivars. By consolidating molecular insights with applied breeding and management practices, this review provides a comprehensive framework that guides researchers in designing genome-informed and field-validated approaches to improve maize resistance to lodging stress and support sustainable crop production systems.

Zea mays↗

PubMed2002

Characterisation of potyviruses from sugarcane and maize in China.

Sugarcane or maize leaves with mosaic virus symptoms were collected from 13 sites in China. Sequence data showed that all 8 samples from maize contained Sugarcane mosaic virus (SCMV); complete sequences were determined from 2 samples and partial sequences (the CI coding region and the 3'-part of the genome) from the others. The 5 sugarcane samples all contained a virus tentatively described as Sorghum mosaic virus (SrMV) and in three of them SCMV was also detected; 2 SrMV sequences and the 3 SCMV ones were completely determined and partial SrMV sequences were obtained from the remaining 3 samples. The features of the complete sequences of SCMV and SrMV are described for the first time. Sequence comparisons and phylogenetic analysis showed three distinct groups of Chinese SCMV sequences (sugarcane isolates from Zhejiang province, a maize isolate from Guangdong and maize isolates from other provinces). The SrMV sequences were similar to one another (> 93% identical nucleotides); they resembled published sequences in the coat protein but were less similar in the 3'-UTR. The complete sequences of SCMV and SrMV had about 70% nucleotides identical to one another and to Maize dwarf mosaic virus (MDMV). MDMV was not detected in any of the samples.

China↗