Profile comparisons of stored mRNA in dry maize seeds from two closely-related geneotypes varying in aflatoxin accumulation
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ABSTRACT:
ORGANISM(S): Zea mays
PROVIDER: GSE34434 | GEO | 2012/07/30
SECONDARY ACCESSION(S): PRJNA149625
REPOSITORIES: GEO
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Project description:Aflatoxin contamination occurring after infection by Aspergillus flavus is a major concern in maize production both pre- and post-harvest. A recent gene expression study of imbibed kernels highlighted induced resistance and gene regulation in kernels. In the present study, stored mRNA was profiled using oligo-nucleotide array. This comparison of stored mRNAs would enhance our understanding of the difference between resistant and susceptible lines at the kernel storage phase. To minimize the effect of different genetic backgrounds on the differential genes between resistant and susceptible lines, two closely related inbred lines were used. Of the two lines, Eyl25 is aflatoxin-resistant (R), and Eyl31 is –susceptible (S). These were derived from a cross between two resistant lines, 1368 and GT-MASK:gk, in the IITA and USDA- ARS collaborative breeding project. Direct comparisons were designed between Eyl25 and Eyl31. Dry kernels from the two lines were selected randomly into four groups to extract total RNA. Four biological replications were performed in the comparison including two dye-swaps.
2012-07-29 | E-GEOD-34434 | biostudies-arrayexpress
Project description:Aflatoxin contamination caused by the opportunistic pathogen A. flavus is a major concern in maize production prior to harvest and during storage. Previous studies indicate that both constitutive and induced resistance are involved in maize kernel defense against A. flavus infection, little is known about molecular mechanisms of mature kernels in response to fungal infection. The purpose of this study is to determine gene expression differences in maize kernels between resistant and susceptible lines in response to A. flavus challenge. To avoid the environmental effects in the field inoculation, a laboratory based inoculation technique Kernel Screening Assay (KSA) was used to challenge kernels with A. flavus. After 72 hours incubation of inoculated and noninculated mature kernels, gene expression profiles of two Near Isogenic Lines (NIL) of Eyl25 (A. flavus resistant) and Eyl31 (A. flavus susceptible) were compared using oligonucleotide array.
2010-10-01 | GSE19883 | GEO
Project description:Aflatoxin contamination caused by the opportunistic pathogen A. flavus is a major concern in maize production prior to harvest and during storage. Previous studies indicate that both constitutive and induced resistance are involved in maize kernel defense against A. flavus infection, little is known about molecular mechanisms of mature kernels in response to fungal infection. The purpose of this study is to determine gene expression differences in maize kernels between resistant and susceptible lines in response to A. flavus challenge. To avoid the environmental effects in the field inoculation, a laboratory based inoculation technique Kernel Screening Assay (KSA) was used to challenge kernels with A. flavus. After 72 hours incubation of inoculated and noninculated mature kernels, gene expression profiles of two Near Isogenic Lines (NIL) of Eyl25 (A. flavus resistant) and Eyl31 (A. flavus susceptible) were compared using oligonucleotide array. Direct comparisons were designed. The comparisons of NIL Eyl25 and Eyl31 include: Treated/Control, Control/Control and Treated/Treated. After 72 hours incubation under KSA conditions, forty seeds used in each A. flavus inoculated and noninculated group were bulked to extract total RNA. Four technical replications were performed in each comparison including two dye-swaps, total 16 hybridization reactions.
2010-10-01 | E-GEOD-19883 | biostudies-arrayexpress
Project description:Aspergillus flavus is one of the major fungal molds that colonize peanut in the field and during storage. The impact to human and animal health and to economy in agriculture and commerce are significant since this mold produces the most potent natural toxins, aflatoxins, which are carcinogenic, mutagenic, immunosuppressive, and teratogenic. A strain of marine Bacillus megaterium isolated from the Yellow Sea of East China was evaluated for its effect to inhibit aflatoxin formation through down-regulating aflatoxin pathway gene expression in A. flavus as demonstrated by genechip analysis in liquid medium and peanuts. The results showed that aflatoxin accumulation in potato dextrose broth liquid medium and liquid minimal medium was almost totally (more than 98%) inhibited by B. megaterium. The expression of many of the aflatoxin biosynthetic genes in the fungus was confirmed to be turned down. Some of the target genes down-regulated by B. megaterium within the whole genome and within the aflatoxin pathway gene cluster (aflF, aflT, aflS, aflJ, aflL, aflX) were identified. These target genes could be used for controlling aflatoxin contamination in crops such as corn, cotton, and peanut. Importantly, the expression of the regulatory gene aflS was found to be significantly down-regulated. The effect of B. megaterium on aflatoxin biosynthesis and genes expression of pathogen was firstly tested in potato dextrose broth (PDB) and glucose minimal salts medium (MM). The cell suspension of B. megaterium (concentration in PDB and MM was finally adjusted to 108 CFU/ml) or sterile distilled water as a control was added into the 100 ml beaker flask containing 15 ml PDB or MM, respectively. Then 100 M-NM-<l of spore suspension (5 M-CM-^W 106 spores/ml) of A. flavus were added into each beaker flask. After 48 h of incubation at 28M-BM-0C at 200 rpm, mycelia were collected, fresh frozen with liquid nitrogen, ground to a fine powder in liquid nitrogen, and stored at -80M-BM-0C for further analysis. The effect of B. megaterium on aflatoxin biosynthesis and genes expression in the A. flavus fungal pathogen was also tested in two types of peanut kernels, UF 715133-1 and Jinhua 1012, respectively. Peanut kernels were wounded (6 mm diameter and approximately 3 mm deep) using a sterile borer and then 20 M-NM-<l of 1 M-CM-^W 108 CFU/ml cell suspension of B. megaterium was inoculated on wounded peanut kernels respectively. Sterile distilled water was also used for inoculation as control. Two hours after bacterial inoculation, 10 M-NM-<l A. flavus spore suspension was inoculated into each wound at a concentration of 106 spores/ml. The kernels were placed in artificial weather chamber to maintain high humidity (85%) and incubated at 28M-BM-0C for 7 days. Each treatment was replicated three times with 20 peanut kernels in each test. The mycelia on kernels were harvested at day 7 and fresh frozen immediately in liquid nitrogen, ground into powder, and stored at -80M-BM-0C for further analysis.
2013-10-22 | E-GEOD-51469 | biostudies-arrayexpress
Project description:Fusarium verticillioides is a detrimental fungus that can contaminate maize grains with mycotoxins that are harmful to human and animal health. Breeding and growing resistant genotypes is one alternative to reduce contamination and subsequent production of mycotoxins by this fungus. However, little is known about the resistant mechanism relevant to breeding in this pathosystem. Therefore, our aim was to identify genes and metabolites that may be related to Fusarium ear rot resistance using resistant and susceptible maize inbreds. Kernels of the resistant inbred showed significantly reduced disease severity, and reduced levels of total fumonisin and ergosterol content compared with the susceptible one. Gene expression data were obtained from microarray hybridizations using F. verticillioides inoculated and non inoculated maize kernels. Differentially expressed sequences were identified and classified into 36 functional categories. Most of the differentially expressed genes were assigned to the categories “protein, RNA, DNA, stress, transport, signaling and cell metabolism”. These genes encode for PR proteins, detoxification and primary metabolism enzymes. Fungal inoculation did not produce considerable changes in gene expression and metabolites in the resistant L4637 inbred, probably due to a preformed or constitutive resistance mechanism. Defense-related genes were induced or repressed in kernels of the susceptible inbred L4674, responding specifically to the pathogen infection. The qRT-PCR in infected silks showed that glucanase, lipid transfer, xylanase inhibitor, PR1 and 26S proteosome transcripts had higher expression ratios in the susceptible line compared to the resistant one in response to fungal infection. Through this study, a global view of differential genes expressed and metabolites concentration during resistance and susceptibility to F. verticillioides inoculation has been obtained, giving additional information about the mechanisms and pathways conferring resistance to this important disease in maize. Global view of differential genes expressed during resistance and susceptibility to F. verticillioides inoculation. Two maize inbred lines : one resistant (L4637) and one susceptible (L4674) to F. verticillioides infection. Two-condition experiment, Inoculated (I) vs. non-inoculated (NI) lines. Biological replicates: 3 . One replicate per array.
2013-08-17 | E-GEOD-40288 | biostudies-arrayexpress
Project description:We investigate the functional complexity of the Plutella xylostella transcriptome in defending against a Bt toxin using Illumina sequencing technology. Over 2,900 differentially expressed unigenes were obtained in resistant P. xylostella comparison to their susceptible counterpart. All the P. xylostella were maintained on cabbage.The susceptible strain (MM) was cultured without exposure to any Bt toxins.Before the sample collected, Cry1Ac-resistant P. xylostella were treated with 750μg/mL Bt toxin Cry1Ac to eliminate the heterozygous individuals. Then the survivors were collected after 48 hours and designed as the resistant sample (MK and GK). Then fourth-instars larvae midgut tissues of MK,GK and MM were collected, respectively, The RNA was extracted and sequenced using Illunima HiSeq 2000.
2014-05-01 | E-GEOD-46399 | biostudies-arrayexpress
Project description:Triticale was used as a model to recognize new components of molecular mechanism of resistance to Fusarium head blight (FHB) in cereals. Fusarium-damaged kernels of two lines distinct in levels of resistance to FHB were applied into a proteome profiling using two-dimensional gel electrophoresis (2-DE) to create protein maps and mass spectrometry to identify the proteins differentially accumulated between the analyzed lines. The 2-DE analysis indicated a total of 23 spots with clear differences in a protein content between the more resistant and more susceptible triticale lines after infection with F. culmorum. A majority of the proteins were involved in a cell carbohydrate metabolism, stressing the importance of this protein group in a plant response to Fusarium infection. The increased accumulation levels of different isoforms of plant beta-amylase were observed for a more susceptible triticale line after inoculation. The more resistant line was characterized by a higher abundance of alpha-amylase inhibitor CM2 subunit.
2018-10-27 | PXD004464 | Pride
Project description:Fungal resistant and susceptible maize genotypes were subjected to Aspergillus flavus spore inoculation and kernels around the infected area were collected 4 days after inoculation. Uninoculated kernels were also collected at 4 days. Microarray experiment was performed to compare the transcriptional profiles of the different genotypes and interpret the genes involved in the associated resistance of the individual genotype to further characterize them as potential molecular markers for resistance.
2011-09-15 | E-MTAB-766 | biostudies-arrayexpress
Project description:Fusarium verticillioides is a detrimental fungus that can contaminate maize grains with mycotoxins that are harmful to human and animal health. Breeding and growing resistant genotypes is one alternative to reduce contamination and subsequent production of mycotoxins by this fungus. However, little is known about the resistant mechanism relevant to breeding in this pathosystem. Therefore, our aim was to identify genes and metabolites that may be related to Fusarium ear rot resistance using resistant and susceptible maize inbreds. Kernels of the resistant inbred showed significantly reduced disease severity, and reduced levels of total fumonisin and ergosterol content compared with the susceptible one. Gene expression data were obtained from microarray hybridizations using F. verticillioides inoculated and non inoculated maize kernels. Differentially expressed sequences were identified and classified into 36 functional categories. Most of the differentially expressed genes were assigned to the categories “protein, RNA, DNA, stress, transport, signaling and cell metabolism”. These genes encode for PR proteins, detoxification and primary metabolism enzymes. Fungal inoculation did not produce considerable changes in gene expression and metabolites in the resistant L4637 inbred, probably due to a preformed or constitutive resistance mechanism. Defense-related genes were induced or repressed in kernels of the susceptible inbred L4674, responding specifically to the pathogen infection. The qRT-PCR in infected silks showed that glucanase, lipid transfer, xylanase inhibitor, PR1 and 26S proteosome transcripts had higher expression ratios in the susceptible line compared to the resistant one in response to fungal infection. Through this study, a global view of differential genes expressed and metabolites concentration during resistance and susceptibility to F. verticillioides inoculation has been obtained, giving additional information about the mechanisms and pathways conferring resistance to this important disease in maize.
2013-08-17 | GSE40288 | GEO
Project description:Maize kernels are susceptible to infection by the opportunistic pathogen Aspergillus flavus. Infection results in reduction of grain quality and contamination of kernels with the highly carcinogenic mycotoxin, aflatoxin. To understand host response to infection by the fungus, transcription of approximately 9,000 maize genes were monitored during the host-pathogen interaction with a custom-designed Affymetrix GeneChip® DNA array. More than 1,000 maize genes were found differentially expressed at a fold change of 2 or greater. This included the up regulation of defense-related genes and signaling pathways. Transcriptional changes also were observed in primary metabolism genes. Starch biosynthetic genes were down regulated during infection, while genes encoding maize hydrolytic enzymes, presumably involved in the degradation of host reserves, were up regulated. These data indicate that infection of the maize kernel A. flavus induced metabolic changes in the kernel, including the production of a defense response, as well as a disruption in kernel development. Maize kernels were mock inoculated at the blister (R2) or dough (R4) stage or inoculated with A. flavus at the blister (R2), milk (R3), dough (R4), or dent (R5) stage, and harvested 4 days later. Each treatment consisted of three biological replications. For each biological replication, 8 kernels were ground and RNA was isolated and further processed.
2014-05-14 | E-GEOD-57629 | biostudies-arrayexpress