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1.
J Agric Food Chem ; 67(35): 9772-9781, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31398019

RESUMO

This study aims to investigate the response profiles of vitamin E and carotenoids on transcription and metabolic levels of sweet corn seedlings under temperature stress. The treated temperatures were set as 10 °C (low temperature, LT), 25 °C (control, CK), and 40 °C (high temperature, HT) for sweet corn seedlings. The gene expression profiles of vitamin E and carotenoids biosynthesis pathways were analyzed by real time quantitative polymerase chain reaction (RT-qPCR), and the composition profiles were analyzed by high performance liquid chromatography (HPLC). Results showed that vitamin E gradually accumulated in response to LT stress but was limited by HT stress. The increase of carotenoids was suppressed by LT stress whereas HT stress promoted it. The existing results elaborated the interactive and competitive relationships of vitamin E and carotenoids in sweet corn seedlings to respond to extreme temperature stress at transcriptional and metabolic levels. The present study would improve sweet corn temperature resilience with integrative knowledge in the future.


Assuntos
Carotenoides/metabolismo , Vitamina E/metabolismo , Zea mays/metabolismo , Carotenoides/análise , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plântula/química , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Estresse Fisiológico , Temperatura Ambiente , Vitamina E/análise , Zea mays/química , Zea mays/genética , Zea mays/crescimento & desenvolvimento
2.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2845-2853, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418211

RESUMO

The safety of feed derived from genetically modified (GM) crops is one of the focuses of attention. To evaluate the ecotoxicological effects of transgenic mCry1Ac maize (BT799) on fish, zebrafish (Danio rerio) were fed extruded feeds containing either 20% GM maize (GMF) or its parental control maize (PF), GM maize meal (GMM) or its parental control maize meal (PMM), and a control commercial feed (CF), respectively. The growth performance, histopathology, reproduction, antioxidant enzyme activity and mRNA expression levels of sensitive protein in the liver were investigated over the course of a 98-day feeding trial. The results showed that transgenic mCry1Ac maize had no significant effect on growth, histopathology of the liver, brain and intestinal tract, fecundity, hatching rate of fertilized eggs, superoxide dismutase (SOD), catalase (CAT) activity, mRNA expression levels of SOD and CAT, or heat shock protein 70 (HSP70) and vitellogenin (VTG) in the liver. However, zebrafish fed the commercial feed exhibited significantly greater weight, longer length, and higher specific growth rate than those fed feeds (GMF and PF) and maize meals (GMM and PMM). The hatching rate of zebrafish in the feed groups was significantly lower than that of the maize meal groups and the commercial feed group. The mRNA transcriptional levels of VTG were significantly higher in the liver for the feed groups (3.85±0.76) than that for the maize meal groups (1.60±0.56). These results suggest that transgenic mCry1Ac maize has no ecotoxicological effects on zebrafish. However, the differences in nutrient composition and palatability between the extruded experimental feeds and the commercial feed would lead to significant diffe-rences in some parameters.


Assuntos
Alimentos Geneticamente Modificados , Zea mays/genética , Ração Animal , Animais , Plantas Geneticamente Modificadas , Testes de Toxicidade , Peixe-Zebra/fisiologia
3.
BMC Plant Biol ; 19(1): 346, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31391002

RESUMO

BACKGROUND: The safety assessment and control of stacked transgenic crops is increasingly important due to continuous crop development and is urgently needed in China. The genetic stability of foreign genes and unintended effects are the primary problems encountered in safety assessment. Omics techniques are useful for addressing these problems. The stacked transgenic maize variety 12-5 × IE034, which has insect-resistant and glyphosate-tolerant traits, was developed via a breeding stack using 12-5 and IE034 as parents. Using 12-5 × IE034, its parents (12-5 and IE034), and different maize varieties as materials, we performed proteomic profiling, molecular characterization and a genetic stability analysis. RESULTS: Our results showed that the copy number of foreign genes in 12-5 × IE034 is identical to that of its parents 12-5 and IE034. Foreign genes can be stably inherited over different generations. Proteomic profiling analysis found no newly expressed proteins in 12-5 × IE034, and the differences in protein expression between 12 and 5 × IE034 and its parents were within the range of variation of conventional maize varieties. The expression levels of key enzymes participating in the shikimic acid pathway which is related to glyphosate tolerance of 12-5 × IE034 were not significantly different from those of its parents or five conventional maize varieties, which indicated that without selective pressure by glyphosate, the introduced EPSPS synthase is not has a pronounced impact on the synthesis of aromatic amino acids in maize. CONCLUSIONS: Stacked-trait development via conventional breeding did not have an impact on the genetic stability of T-DNA, and the impact of stacked breeding on the maize proteome was less significant than that of genotypic differences. The results of this study provide a theoretical basis for the development of a safety assessment approach for stacked-trait transgenic crops in China.


Assuntos
Variação Genética , Melhoramento Vegetal , Plantas Geneticamente Modificadas , Zea mays/genética , China , Inocuidade dos Alimentos , Dosagem de Genes , Instabilidade Genômica , Análise de Perigos e Pontos Críticos de Controle , Proteômica
4.
BMC Plant Biol ; 19(1): 351, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412785

RESUMO

BACKGROUND: Rubisco activase (RCA) regulates the activity of Rubisco and is a key enzyme of photosynthesis. RCA expression was widely reported to affect plant photosynthesis and crop yield, but the molecular basis of natural variation in RCA expression in a wide range of maize materials has not been fully elucidated. RESULTS: In this study, correlation analysis in approximately 200 maize inbred lines revealed a significantly positive correlation between the expression of maize RCA gene ZmRCAß and grain yield. A genome-wide association study revealed both cis-expression quantitative trait loci (cis-eQTLs) and trans-eQTLs underlying the expression of ZmRCAß, with the latter playing a more important role. Further allele mining and genetic transformation analysis showed that a 2-bp insertion and a 14-bp insertion in the promoter of ZmRCAß conferred increased gene expression. Because rice is reported to have higher RCA gene expression than does maize, we subsequently compared the genetic factors underlying RCA gene expression between maize and rice. The promoter activity of the rice RCA gene was shown to be stronger than that of the maize RCA gene, suggesting that replacing the maize RCA gene promoter with that of the rice RCA gene would improve the expression of RCA in maize. CONCLUSION: Our results revealed two DNA polymorphisms regulating maize RCA gene ZmRCAß expression, and the RCA gene promoter activity of rice was stronger than that of maize. This work increased understanding of the genetic mechanism that underlies RCA gene expression and identify new targets for both genetic engineering and selection for maize yield improvement.


Assuntos
Oryza/genética , Fotossíntese/genética , Proteínas de Plantas/genética , Zea mays/genética , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Oryza/metabolismo , Oryza/fisiologia , Folhas de Planta , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Regiões Promotoras Genéticas , Locos de Características Quantitativas , Ribulose-Bifosfato Carboxilase , Zea mays/metabolismo , Zea mays/fisiologia
5.
Science ; 365(6454): 640-641, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31416949
6.
J Agric Food Chem ; 67(32): 8905-8918, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31380641

RESUMO

NAC TFs play crucial roles in response to abiotic stresses in plants. Here, ZmNAC071 was identified as a nuclear located transcriptional repressor. Overexpression of ZmNAC071 in Arabidopsis enhanced sensitivity of transgenic plants to ABA and osmotic stress. The expression levels of SODs, PODs, P5CSs, and AtMYB61 were inhibited by ZmNAC071, which results in reduced ROS scavenging and proline content, increased ROS level, and water loss. Besides, the expression levels of some ABA or abiotic stress-related genes, like ABIs, RD29A, DREBs, and LEAs were also significantly inhibited by ZmNAC071. Yeast one-hybrid assay demonstrated that ZmNAC071 specifically bound to the cis-acting elements containing CGT[G/A] core sequences in the promoter of stress-related genes, suggesting that ZmNAC071 may participate in the regulation of transcription of these genes through recognizing the core sequences CGT[G/A]. These results will facilitate further studies concerning the cis-elements and downstream genes targeted by ZmNAC071 in maize.


Assuntos
Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Ácido Ascórbico/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/fisiologia , Fatores de Transcrição/genética , Zea mays/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação para Baixo/efeitos dos fármacos , Pressão Osmótica , Plantas Geneticamente Modificadas/genética , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico , Fatores de Transcrição/metabolismo
7.
BMC Plant Biol ; 19(1): 310, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31307401

RESUMO

BACKGROUND: The hypersensitive defense response (HR) in plants is a fast, localized necrotic response around the point of pathogen ingress. HR is usually triggered by a pathogen recognition event mediated by a nucleotide-binding site, leucine-rich repeat (NLR) protein. The autoactive maize NLR gene Rp1-D21 confers a spontaneous HR response in the absence of pathogen recognition. Previous work identified a set of loci associated with variation in the strength of Rp1-D21-induced HR. A polygalacturonase gene homolog, here termed ZmPGH1, was identified as a possible causal gene at one of these loci on chromosome 7. RESULTS: Expression of ZmPGH1 inhibited the HR-inducing activity of both Rp1-D21 and that of another autoactive NLR, RPM1(D505V), in a Nicotiana benthamiana transient expression assay system. Overexpression of ZmPGH1 in a transposon insertion line of maize was associated with suppression of chemically-induced programmed cell death and with suppression of HR induced by Rp1-D21 in maize plants grown in the field. CONCLUSIONS: ZmPGH1 functions as a suppressor of programmed cell death induced by at least two autoactive NLR proteins and by two chemical inducers. These findings deepen our understanding of the control of the HR in plants.


Assuntos
Apoptose/fisiologia , Proteínas de Plantas/fisiologia , Poligalacturonase/fisiologia , Zea mays/fisiologia , Apoptose/genética , Mapeamento Cromossômico , Cromossomos de Plantas , Genes de Plantas , Leucina , Proteínas de Plantas/química , Proteínas de Plantas/genética , Poligalacturonase/química , Poligalacturonase/genética , Recombinação Genética , Sequências Repetitivas de Aminoácidos , Tabaco/genética , Zea mays/enzimologia , Zea mays/genética , Zea mays/imunologia
8.
BMC Plant Biol ; 19(1): 318, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31311506

RESUMO

BACKGROUND: Single Nucleotide Polymorphism (SNP) array and re-sequencing technologies have different properties (e.g. calling rate, minor allele frequency profile) and drawbacks (e.g. ascertainment bias). This lead us to study their complementarity and the consequences of using them separately or combined in diversity analyses and Genome-Wide Association Studies (GWAS). We performed GWAS on three traits (grain yield, plant height and male flowering time) measured in 22 environments on a panel of 247 F1 hybrids obtained by crossing 247 diverse dent maize inbred lines with a same flint line. The 247 lines were genotyped using three genotyping technologies (Genotyping-By-Sequencing, Illumina Infinium 50 K and Affymetrix Axiom 600 K arrays). RESULTS: The effects of ascertainment bias of the 50 K and 600 K arrays were negligible for deciphering global genetic trends of diversity and for estimating relatedness in this panel. We developed an original approach based on linkage disequilibrium (LD) extent in order to determine whether SNPs significantly associated with a trait and that are physically linked should be considered as a single Quantitative Trait Locus (QTL) or several independent QTLs. Using this approach, we showed that the combination of the three technologies, which have different SNP distributions and densities, allowed us to detect more QTLs (gain in power) and potentially refine the localization of the causal polymorphisms (gain in resolution). CONCLUSIONS: Conceptually different technologies are complementary for detecting QTLs by tagging different haplotypes in association studies. Considering LD, marker density and the combination of different technologies (SNP-arrays and re-sequencing), the genotypic data available were most likely enough to well represent polymorphisms in the centromeric regions, whereas using more markers would be beneficial for telomeric regions.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Técnicas de Genotipagem , Haplótipos , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Zea mays/genética , Alelos , Biodiversidade , Cromossomos de Plantas , Marcadores Genéticos , Genoma de Planta , Desequilíbrio de Ligação , Zea mays/crescimento & desenvolvimento
9.
Gene ; 714: 143984, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31330237

RESUMO

Intrinsically disordered proteins (IDPs) are highly abundant in eukaryotic proteomes and involved in key biological and cellular processes. Although some resources of disordered protein predictions are available from animal and plant proteomes, those related to cereals are largely unknown. Here, we present an overview of IDPomes from Oryza sativa, Zea mays, Sorghum bicolor and Brachypodium distachyon. The work includes a comparative analysis with the model plant Arabidopsis thaliana. The data show that the intrinsic disorder content increases with the proteome size. Gene Ontology analysis reveals that IDPs in the studied species are involved mainly in regulation of cellular and metabolic processes and responses to stimulus. Our findings strongly suggest that higher plants may use common cellular and regulatory mechanisms for adaptation to various environmental constraints.


Assuntos
Grão Comestível/genética , Proteínas Intrinsicamente Desordenadas/genética , Adaptação Biológica/genética , Arabidopsis/genética , Brachypodium/genética , Ontologia Genética , Genômica/métodos , Oryza/genética , Proteínas de Plantas/genética , Proteoma/genética , Sorghum/genética , Zea mays/genética
10.
J Agric Food Chem ; 67(26): 7466-7474, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31184886

RESUMO

The ZMM28 protein encoded by the zmm28 gene is endogenous to maize. DP202216 maize was genetically modified to increase and extend expression of the zmm28 gene relative to native zmm28 gene expression, resulting in plants with enhanced grain yield potential. Evaluation of the history of safe use (HOSU) is one component of the safety assessment framework for a newly expressed protein in a GM crop. The deduced amino acid sequence of the introduced ZMM28 protein in DP202216 maize is identical to the ZMM28 protein in nonmodified conventional maize. The ZMM28 protein has also been found in selected varieties of sweet corn kernels, and closely related proteins are found in other commonly consumed food crops. Concentrations of the ZMM28 protein in event DP202216 maize, conventional maize, and sweet corn are reported. This information supports, in part, the evaluation of HOSU, which can be leveraged in the safety assessment of the ZMM28 protein. Additional studies will be considered in the food and feed safety assessment of the DP202216 maize event.


Assuntos
Proteínas de Plantas/química , Plantas Geneticamente Modificadas/química , Zea mays/química , Sequência de Aminoácidos , Qualidade de Produtos para o Consumidor , Inocuidade dos Alimentos , Alimentos Geneticamente Modificados , Humanos , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Alinhamento de Sequência , Zea mays/genética , Zea mays/metabolismo
11.
BMC Plant Biol ; 19(1): 273, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31234785

RESUMO

BACKGROUND: Heterosis is the superior performance of F1 hybrids relative to their parental lines for a wide range of traits. In this study, expression profiling and heterosis associated genes were analyzed by RNA sequencing (RNA-Seq) in seedlings of the maize hybrid An'nong 591 and its parental lines under control and heat stress conditions. RESULTS: Through performing nine pairwise comparisons, the maximum number of differentially expressed genes (DEGs) was detected between the two parental lines, and the minimum number was identified between the F1 hybrid and the paternal lines under both conditions, which suggested greater genetic contribution of the paternal line to heat stress tolerance. Gene Ontology (GO) enrichment analysis of the 4518 common DEGs indicated that GO terms associated with diverse stress responses and photosynthesis were highly overrepresented in the 76 significant terms of the biological process category. A total of 3970 and 7653 genes exhibited nonadditive expression under control and heat stress, respectively. Among these genes, 2253 (56.8%) genes overlapped, suggesting that nonadditive genes tend to be conserved in expression. In addition, 5400 nonadditive genes were found to be specific for heat stress condition, and further GO analysis indicated that terms associated with stress responses were significantly overrepresented, and 60 genes were assigned to the GO term response to heat. Pathway enrichment analysis indicated that 113 genes were involved in spliceosome metabolic pathways. Nineteen of the 33 overlapping genes assigned to the GO term response to heat showed significantly higher number of alternative splicing (AS) events under heat stress than under control conditions, suggesting that AS of these genes play an important role in response to heat stress. CONCLUSIONS: This study reveals the transcriptomic divergence of the maize F1 hybrid and its parental lines under control and heat stress conditions, and provides insight into the underlying molecular mechanisms of heterosis and the response to heat stress in maize.


Assuntos
Genes de Plantas , Resposta ao Choque Térmico/genética , Zea mays/genética , Genoma de Planta , Vigor Híbrido , Hibridização Genética , Transcriptoma , Zea mays/fisiologia
12.
Nat Commun ; 10(1): 2633, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201330

RESUMO

Long-range chromatin interactions are important for transcriptional regulation of genes, many of which are related to complex agronomics traits. However, the pattern of three-dimensional chromatin interactions remains unclear in plants. Here we report the generation of chromatin interaction analysis by paired-end tag sequencing (ChIA-PET) data and the construction of extensive H3K4me3- and H3K27ac-centered chromatin interaction maps in maize. Results show that the interacting patterns between proximal and distal regulatory regions of genes are highly complex and dynamic. Genes with chromatin interactions have higher expression levels than those without interactions. Genes with proximal-proximal interactions prefer to be transcriptionally coordinated. Tissue-specific proximal-distal interactions are associated with tissue-specific expression of genes. Interactions between proximal and distal regulatory regions further interweave into organized network communities that are enriched in specific biological functions. The high-resolution chromatin interaction maps will help to understand the transcription regulation of genes associated with complex agronomic traits of maize.


Assuntos
Cromatina/metabolismo , Regulação da Expressão Gênica de Plantas , Sequências Reguladoras de Ácido Nucleico/genética , Transcrição Genética/genética , Zea mays/genética , Cromatina/genética , Imunoprecipitação da Cromatina , Mapeamento Cromossômico , Produção Agrícola , Redes Reguladoras de Genes , Estudo de Associação Genômica Ampla , Histonas/genética , Histonas/imunologia , Regiões Promotoras Genéticas , Locos de Características Quantitativas/genética
13.
Nat Commun ; 10(1): 2632, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201335

RESUMO

Chromatin loops connect regulatory elements to their target genes. They serve as bridges between transcriptional regulation and phenotypic variation in mammals. However, spatial organization of regulatory elements and its impact on gene expression in plants remain unclear. Here, we characterize epigenetic features of active promoter proximal regions and candidate distal regulatory elements to construct high-resolution chromatin interaction maps for maize via long-read chromatin interaction analysis by paired-end tag sequencing (ChIA-PET). The maps indicate that chromatin loops are formed between regulatory elements, and that gene pairs between promoter proximal regions tend to be co-expressed. The maps also demonstrated the topological basis of quantitative trait loci which influence gene expression and phenotype. Many promoter proximal regions are involved in chromatin loops with distal regulatory elements, which regulate important agronomic traits. Collectively, these maps provide a high-resolution view of 3D maize genome architecture, and its role in gene expression and phenotypic variation.


Assuntos
Cromatina/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes/genética , Locos de Características Quantitativas/genética , Zea mays/genética , Cromatina/metabolismo , Imunoprecipitação da Cromatina , Mapeamento Cromossômico , Produção Agrícola , Elementos Facilitadores Genéticos/genética , Epigênese Genética , Epigenômica/métodos , Genoma de Planta/genética , Estudo de Associação Genômica Ampla , Mutação , Fenótipo , Regiões Promotoras Genéticas/genética
14.
Plant Dis ; 103(8): 2100-2107, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31215852

RESUMO

Head smut, caused by the fungus Sporisorium reilianum, is a devastating global disease of maize (Zea mays). In the present study, maize seedlings were artificially inoculated with compatible mating-type strains of S. reilianum by needle inoculation of mesocotyls (NIM) or by soaking inoculation of radicles (SIR). After NIM or SIR, Huangzao4 mesocotyls exhibited severe damage with brownish discoloration and necrosis, whereas Mo17 mesocotyls exhibited few lesions. Fluorescence and electron microscopy showed that S. reilianum infected maize within 0.5 day after SIR and mainly colonized the phloem. With longer incubation, the density of S. reilianum hyphae increased in the vascular bundles, concentrated mainly in the phloem. In Mo17, infected cells exhibited apoptosis-like features, and hyphae became sequestered within dead cells. In contrast, in Huangzao4, pathogen invasion resulted in autophagy that failed to prevent hyphal spreading. The growth of S. reilianum hyphae diminished at 6 days after inoculation when expression of the R genes ZmWAK and ZmNL peaked. Thus, 6 days after SIR inoculation might be an important time for inhibiting the progress of S. reilianum infection in maize. The results of this study will provide a basis for further analysis of the mechanisms of maize resistance to S. reilianum.


Assuntos
Resistência à Doença , Regulação da Expressão Gênica de Plantas , Ustilaginales , Zea mays , Resistência à Doença/genética , Hifas , Doenças das Plantas/microbiologia , Ustilaginales/citologia , Zea mays/citologia , Zea mays/genética , Zea mays/microbiologia
15.
Carbohydr Polym ; 219: 172-180, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151514

RESUMO

With respect of the partial molecular degradation of the starch polysaccharides, the impact of the acid-thinning process on the specific starch properties of two corn genotypes was investigated. A high amylose corn (HACS) and a waxy corn (WxCS) starch were hydrolyzed using HCl in the laboratory scale slurry process (40% w/w, 30 °C). The acid concentration (0.3, 0.6 and 0.9 M) as well as the hydrolysis time (4, 10 and 20 h) were graded systematically (experimental design) and the obtained modified starch genotypes characterized comprehensively. As revealed by scanning electron micoscopy (SEM), the supramolecular structure was preserved in general, and the carbohydrate solubilization was limited to about 2-3 %. Molecularly dispersed solutions were characterized by means of size exclusion chromatography-multi angle laser light scattering-differential refractive index detection (SEC-MALS-DRI). Both acid concentration and hydrolysis time reduced the molar mass (MM) of the starch [HACS: 4.4∙106 (native)…1.2∙106 g∙mol-1 (highest degree of degradation); WxCS: 49.7∙106 (native)…6.4∙106 g∙mol-1 (highest degree of degradation)], the amylose (AM) fraction as well as the amylopectin (AP) branch chain length systematically. Perceptible differences in dependence on starch variety were ascertained and discussed. The molecular properties of the investigated acid-thinned genotypes are selectively controllable with the hydrolysis process. The relationship between modification process, starch's molecular state, and resulting functional properties was examined in the second part of the study.


Assuntos
Amilopectina/química , Amilose/química , Amido/química , Zea mays/metabolismo , Análise de Variância , Cromatografia em Gel , Genótipo , Ácido Clorídrico/química , Hidrólise , Concentração Osmolar , Fatores de Tempo , Zea mays/genética
16.
Nat Genet ; 51(6): 1052-1059, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31152161

RESUMO

Maize is one of the most important crops globally, and it shows remarkable genetic diversity. Knowledge of this diversity could help in crop improvement; however, gold-standard genomes have been elucidated only for modern temperate varieties. Here, we present a high-quality reference genome (contig N50 of 15.78 megabases) of the maize small-kernel inbred line, which is derived from a tropical landrace. Using haplotype maps derived from B73, Mo17 and SK, we identified 80,614 polymorphic structural variants across 521 diverse lines. Approximately 22% of these variants could not be detected by traditional single-nucleotide-polymorphism-based approaches, and some of them could affect gene expression and trait performance. To illustrate the utility of the diverse SK line, we used it to perform map-based cloning of a major effect quantitative trait locus controlling kernel weight-a key trait selected during maize improvement. The underlying candidate gene ZmBARELY ANY MERISTEM1d provides a target for increasing crop yields.


Assuntos
Estudos de Associação Genética , Genoma de Planta , Genômica , Fenótipo , Zea mays/genética , Biologia Computacional/métodos , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Endogamia , Anotação de Sequência Molecular , Melhoramento Vegetal , Plantas Geneticamente Modificadas , Polimorfismo de Nucleotídeo Único , Característica Quantitativa Herdável
17.
Plant Physiol Biochem ; 141: 415-422, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229926

RESUMO

This study aimed to investigate the possible alleviating effect of chitosan on salt-induced growth retardation and oxidative stress and to elucidate whether this effect is linked to activation of mitochondrial respiration on the basis of alternative respiration in maize seedlings. Salt stress significantly reduced root length and plant height in comparison to the control, whereas foliar application of chitosan ameliorated the adverse effect of salinity to a certain degree. Moreover, chitosan resulted in plant growth promotion as compared to unstressed seedlings. The separate applications of chitosan and salt had a stimulatory effect on the activities of antioxidant enzymes; however, combined application of chitosan and salt were more effective than that of chitosan or salt alone. Similarly, mitochondrial total respiration rate (Vt) and alternative respiration capacity (Valt) were increased by separate applications of chitosan and salt; however, the combination of chitosan and salt gave the highest values for these parameters. The highest values of Valt/Vt was recorded at seedlings treated with salt plus chitosan. Similarly, cytochrome respiration capacity was also increased by chitosan in both stress-free and stressed conditions. In addition, AOX1, encoding alternative oxidase, was significantly upregulated by chitosan and/or salt. The maximum transcript level was recorded at seedlings treated with salt plus chitosan. Chitosan also significantly decreased superoxide anion and hydrogen peroxide contents and lipid peroxidation level under normal and the stressed conditions. These results suggest that the mitigating effect of chitosan on salt stress is linked to activation of alternative respiration at biochemical and molecular level.


Assuntos
Quitosana/química , Regulação da Expressão Gênica de Plantas , Proteínas Mitocondriais/metabolismo , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Tolerância ao Sal , Plântula/genética , Zea mays/genética , Antioxidantes/metabolismo , Citocromos/metabolismo , Perfilação da Expressão Gênica , Peroxidação de Lipídeos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Estresse Oxidativo , Oxirredutases/genética , Proteínas de Plantas/genética , RNA/metabolismo , Estresse Fisiológico , Zea mays/enzimologia
18.
Nat Plants ; 5(6): 575-580, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31182848

RESUMO

Doubled haploid (DH) breeding based on in vivo haploid induction has led to a new approach for maize breeding1. All modern haploid inducers used in DH breeding are derived from the haploid inducer line Stock6. Two key quantitative trait loci, qhir1 and qhir8, lead to high-frequency haploid induction2. Mutation of the gene MTL/ZmPLA1/NLD in qhir1 could generate a ~2% haploid induction rate (HIR)3-5; nevertheless, this mutation is insufficient for modern haploid inducers whose average HIR is ~10%6. Therefore, cloning of the gene underlying qhir8 is important for illuminating the genetic basis of haploid induction. Here, we present the discovery that mutation of a non-Stock6-originating gene in qhir8, namely, ZmDMP, enhances and triggers haploid induction. ZmDMP was identified by map-based cloning and further verified by CRISPR-Cas9-mediated knockout experiments. A single-nucleotide change in ZmDMP leads to a 2-3-fold increase in the HIR. ZmDMP knockout triggered haploid induction with a HIR of 0.1-0.3% and exhibited a greater ability to increase the HIR by 5-6-fold in the presence of mtl/zmpla1/nld. ZmDMP was highly expressed during the late stage of pollen development and localized to the plasma membrane. These findings provide important approaches for studying the molecular mechanism of haploid induction and improving DH breeding efficiency in maize.


Assuntos
Haploidia , Proteínas de Membrana/genética , Proteínas de Plantas/genética , Zea mays/genética , Mapeamento Cromossômico , Cromossomos de Plantas , Técnicas de Inativação de Genes , Mutação
19.
Plant Physiol Biochem ; 141: 380-387, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31220804

RESUMO

Maize is a critically important staple crop in the whole world, which has contributed to both economic security and food in planting areas. The main target for researchers and breeding is the improvement of maize quality and yield. The use of computational biology methods combined with multi-omics for selecting biomolecules of interest for maize breeding has been receiving more attention. Moreover, the rapid growth of high-throughput sequencing data provides the opportunity to explore biomolecules of interest at the molecular level in maize. Furthermore, we constructed weighted networks for each of the omics and then integrated them into a final fused weighted network based on a nonlinear combination method. We also analyzed the final fused network and mined the orphan nodes, some of which were shown to be transcription factors that played a key role in maize development. This study could help to improve maize production via insights at the multi-omics level and provide a new perspective for maize researchers. All related data have been released at http://lab.malab.cn/∼jj/maize.htm.


Assuntos
Biologia Computacional/métodos , Genômica/métodos , Proteômica/métodos , Zea mays/genética , Algoritmos , Produtos Agrícolas/genética , Bases de Dados Factuais , Estudos de Associação Genética , Variação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Dinâmica não Linear , Proteoma , Transcriptoma
20.
Plant Sci ; 283: 375-384, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128708

RESUMO

High temperature directly affects the yield and quality of crops. Plant Hsfs play vital roles in plant response to heat shock. In the present study, ZmHsf05 was isolated from maize (Zea mays L.) using homologous cloning methods. The sequencing analysis demonstrated that CDS of ZmHsf05 was 1080 bp length and encoded a protein containing 359 amino acids. The putative amino acid sequence of ZmHsf05 contained typical Hsf domains, such as DBD, OD, NLS and AHA motif. Subcellular localization assays displayed that the ZmHsf05 is localized to the nucleus. ZmHsf05 was expressed in many maize tissues and its expression level was increased by heat stress treatment. ZmHsf05 rescued the reduced thermotolerance of the athsfa2 mutant in Arabidopsis seedlings. Arabidopsis seedlings of ZmHsf05-overexpressing increased both the basal and acquired thermotolerances. After heat stress, the ZmHsf05-overexpressing lines showed enhanced survival rate and chlorophyll content compared with WT seedlings. The expression of Hsps was up-regulated in the ZmHsf05-overexpressing Arabidopsis lines after heat stress treatment. These results suggested that ZmHsf05 plays an important role in both basal and acquired thermotolerance in plants.


Assuntos
Fatores de Transcrição de Choque Térmico/fisiologia , Proteínas de Plantas/fisiologia , Termotolerância , Zea mays/fisiologia , Arabidopsis/genética , Fatores de Transcrição de Choque Térmico/genética , Resposta ao Choque Térmico , Mutação , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Reação em Cadeia da Polimerase , Alinhamento de Sequência , Termotolerância/genética , Técnicas do Sistema de Duplo-Híbrido , Zea mays/genética , Zea mays/metabolismo
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