Transcriptional profiles uncover Aspergillus flavus induced resistance in mature maize kernels
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ABSTRACT:
ORGANISM(S): Zea mays
PROVIDER: GSE19883 | GEO | 2010/10/01
SECONDARY ACCESSION(S): PRJNA122021
REPOSITORIES: GEO
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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: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
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.
2014-05-14 | GSE57629 | GEO
Project description:The experiment consisted of a field design containing two maize inbred lines Va35 and Mp313E. Va35 has yellow kernels and is susceptible to kernel infection by Aspergillus flavus (A. flavus). Mp313E is a white dent maize inbred line and was released primarily as a source of resistance to kernel infection by A. flavus. The test ears were inoculated with Aspergillus flavus and collected two days after inoculation. Non-inoculated ears collected 16 days after pollination were also used as a control. The microarray experimental design was a randomized complete block design with three replications. One microarray slide was used for each field plot. Each slide contained the inoculated and non-inoculated sub-treatments. A second slide for one replication of each genotype contained a dye swap for the inoculation treatment and three subsamples (dots) within the slide represented each contig. Keywords: Direct comparison
2007-11-09 | GSE9546 | GEO
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: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: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.
2012-07-30 | GSE34434 | GEO
Project description:Peroxidase (POD) activity was found to be positively correlated with insect resistance in maize kernels. Thus, we purified active PODs from (Zea mays, p84C3) kernels and subjected to LC-MS/MS analyses. To verify the identified putative plant PODs, we produced them by recombinant expression in E. coli. Whereas B4FFK9 did not display in vitro activity, B6T173 (ZmPrx35) was active and also exhibits a heme cofactor. B6T173 accounts for about 80% of the POD activity in the kernel, according to densitometric evaluation.
2015-08-21 | PXD002166 | Pride
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