The effect of temperature on Natural Antisense Transcript (NAT) expression in Aspergillus flavus
Ontology highlight
ABSTRACT:
ORGANISM(S): Zea mays Aspergillus flavus
PROVIDER: GSE12594 | GEO | 2009/03/25
SECONDARY ACCESSION(S): PRJNA112843
REPOSITORIES: GEO
Similar Datasets
Project description:Naturally occurring Antisense Transcripts (NATs) compose an emerging group of regulatory RNAs. These regulatory elements appear in all organisms examined, but little is known about global expression of NATs in fungi. Analysis of currently available EST sequences suggests that 352 cis NATs are present in Aspergillus flavus. An Affymetrix GeneChip® microarray containing probes for these cis NATs, as well as all predicted genes in A. flavus, allowed a whole genome expression analysis of these elements in response to two ecologically important temperatures for the fungus. RNA expression analysis showed that 32 NATs and 2709 genes were differentially expressed between 37°C, the optimum temperature for growth, and 28°C, the conducive temperature for the biosynthesis of aflatoxin (AF) and many other secondary metabolites. These NATs correspond to sense genes with diverse functions including transcription initiation, carbohydrate processing and binding, temperature sensitive morphogenesis, and secondary metabolism. This is the first report of a whole genome transcriptional analysis of NAT expression in a fungus and shows that although less than 10% of putative NATs are differentially expressed in response to temperature, some of the NAT-cis gene interactions are likely to be important. Keywords: temperature response 3 samples (reps) for each temperature treatment were analyzed with a total of 6 samples.
2010-06-21 | E-GEOD-12594 | biostudies-arrayexpress
Project description:To better understand the effect of temperature on mycotoxin biosynthesis, RNA-Seq technology was used to profile the Aspergillus flavus transcriptome under different temperature conditions. This approachallowed us to quantify transcript abundance for over 80% of fungal genes including 1,153 genes that were differentially expressed at 30M-BM-0C and 37M-BM-0C. Wleven of the 55 secondary metabolite clusters were up-regulated at the lower temperature, including aflatoxin biosynthesis genes, which were among the most highly up-expressed genes. On average, transcript abundance for the 30 aflatoxin biosynthesis genes was 3,300 times greater at 30M-BM-0C as compared to 37M-BM-0C. The results are consistent with the view that high temperature negatively affects aflatoxin production by turning down transcription of the two key transcriptional regulators, aflR and aflS. Subtle changes in the expression levels of aflS to aflR appear to control transcription activation of the aflatoxin cluster. 2 samples examined: from the fungus grown at 30M-BM-0C and 37M-BM-0C
2011-06-16 | E-GEOD-30031 | biostudies-arrayexpress
Project description:Aspergillus flavus first gained scientific attention for its production of aflatoxin, the most potent naturally occurring toxin and hepatocarcinogenic secondary metabolite. For several decades, The DNA methylation status of A. flavus remains to be controversial. We first applied bisulfite sequencing, the gold standard at present, in conjunction with a biological replicate strategy to investigate the DNA methylation profiling of A. flavus genome. Our results reveal that the DNA methylation level of this fungus turns out to be negligible, comparable to the unmethylated lambda DNA we set as the false positive control of our bisulfite experiments. When comparing the DNA methyltransferase homolog of A. flauvs with that from several selected hypermethylated speices, we find that the DNA methyltransferase homolog of A.flavus as well as the other Aspergillus members groups closely with the RID from Neurospora crassa and Masc1 from Ascobolus immerses, which has been reported as DMT-incapable, but it diverges distantly from the other capable DNA methyltransferases. We observe significant depletion of repeat components within the A. flavus, which may possibly explain the lack of DNA methylation in this fungus. What's more, the RIP-index of the repeat of A. flavus turns out to be higher than the fungi without RID-like enzyme, suggesting this asexual fungus may possibly possess RIP process during the obscure sexual-stage which is very evanescent and may potentially related to DNA methylation. This work contributes to our understanding on the DNA methylation status of A. flavus. Also, it reinforces our views on the DNA methylation in fungal species. What's more, our strategy of applying bisulfite sequencing to DNA methylation detection on species with low DNA methylation may serve as a reference for later scientific investigations on other hypomethylated species. Two replicates were subjected to bisulfite conversion independently, unmethylated lambda DNA as a false positive control is added to both replicates.
2012-03-01 | E-GEOD-32177 | biostudies-arrayexpress
Project description:We systematically identified long noncoding natural antisense transcripts (lncNATs), defined as lncRNAs transcribed from the opposite DNA strand of coding or noncoding genes. We identified in total 37,238 sense-antisense transcript pairs and found 70% mRNAs are associated with antisense transcripts in Arabidopsis. To investigate the role of NATs in response to white light treatment, we designed an Agilent custom array, ATH NAT array, and analyzed WT seedlings grown in the dark (0h) and seedlings undergoing de-etiolation in continuous white light for 1h and 6h. To obtain information on organ-specific transcriptome profiles, we further dissected seedlings into cotyledons, hypocotyls and roots. We examined the abundance of NATs in etiolated seedlings and seedlings undergoing de-etiolation in continuous white light for 1/6h. Seedlings were further dissected into cotyledons, hypocotyls and roots. RNAs from 3 biological replicates of each of the 3 organs were separately hybridized to ATH NAT arrays to profile light-regulated NAT pairs.
2013-12-23 | E-GEOD-49382 | biostudies-arrayexpress
Project description:Aspergillus flavus first gained scientific attention for its production of aflatoxin, the most potent naturally occurring toxin and hepatocarcinogenic secondary metabolite. For several decades, The DNA methylation status of A. flavus remains to be controversial. We first applied bisulfite sequencing, the gold standard at present, in conjunction with a biological replicate strategy to investigate the DNA methylation profiling of A. flavus genome. Our results reveal that the DNA methylation level of this fungus turns out to be negligible, comparable to the unmethylated lambda DNA we set as the false positive control of our bisulfite experiments. When comparing the DNA methyltransferase homolog of A. flauvs with that from several selected hypermethylated speices, we find that the DNA methyltransferase homolog of A.flavus as well as the other Aspergillus members groups closely with the RID from Neurospora crassa and Masc1 from Ascobolus immerses, which has been reported as DMT-incapable, but it diverges distantly from the other capable DNA methyltransferases. We observe significant depletion of repeat components within the A. flavus, which may possibly explain the lack of DNA methylation in this fungus. What's more, the RIP-index of the repeat of A. flavus turns out to be higher than the fungi without RID-like enzyme, suggesting this asexual fungus may possibly possess RIP process during the obscure sexual-stage which is very evanescent and may potentially related to DNA methylation. This work contributes to our understanding on the DNA methylation status of A. flavus. Also, it reinforces our views on the DNA methylation in fungal species. What's more, our strategy of applying bisulfite sequencing to DNA methylation detection on species with low DNA methylation may serve as a reference for later scientific investigations on other hypomethylated species.
2012-03-01 | GSE32177 | GEO
Project description:Protein lysine acetylation is a prevalent post-translational modification that plays pivotal roles in various biological processes in both prokaryotes and eukaryotes. Aspergillus flavus, as a fungus of aflatoxin producer, has attracted tremendous attention due to its health impact on agricultural commodities. Here, we performed the first lysine-acetylome mapping in this filamentous fungus using immune-affinity-based purification integrated with high-resolution mass spectrometry. Overall, we identified 1383 lysine-acetylation sites in 652 acetylated proteins, which account for 5.18% of the total proteins in A. flavus. The acetylated proteins are involved in various cellular processes involving the ribosome, carbon metabolism, antibiotic biosynthesis, secondary metabolites, and the citrate cycle and are distributed in diverse subcellular locations according to bioinformatics analysis. We demonstrated for the first time the acetylation of fatty acid synthase α and β encoded by aflA and aflB involved in the aflatoxin-biosynthesis pathway (cluster 54), as well as backbone enzymes from secondary metabolite clusters 20 and 21 encoded by AFLA_062860 and AFLA_064240, suggesting important roles for acetylation associated with these processes. Our findings illustrating abundant lysine acetylation in A. flavus expanded the understanding of the fungal acetylome and provided insight into the regulatory roles of acetylation in secondary metabolism.
2017-06-12 | PXD004802 | Pride
Project description:Several are the inputs which are able to modulate mycotoxin synthesis. In particular, when a fungus receives an external stimulus reacts by activating, through a quite well-defined signal cascade, an evident switch in its lifestyle. This profound change is also due to the activation of global gene regulators and, in particular, of transcription factors able to switch on the mycotoxin gene clusters expression. Aflatoxins (AF) are harmful carcinogenic compounds produced mainly by Aspergillus flavus and A. parasiticus. AF are produced during the contamination of maize kernels into the field, even if their role in phyto-toxicity is not yet assessed. Nevertheless, AF biosynthesis is tightly regulated by host-derived signals. Recently, the nature of some of these signals have been elucidated. In particular, a role in susceptibility and resistance of maize to A. flavus contamination has been assigned to some plant oxylipins. These findings draw a scenario in which a complex interplay is under way between A. flavus and maize. For uncovering all the implications of this cross-talk we decide to follow a holistic approach. In particular, we designed experimental conditions aimed to mimic the different phases of A. flavus infection cycle on maize and then by performing a microarray analysis on the harvested mycelia. The microarray data set has been processed for performing the differential expression analysis of almost 14000 gene probes, the pathway analysis based on the gene ontology and inter pro annotations, the secondary metabolites cluster co-expression analysis and an identification of groups of co-expressed neighbor genes, possibly associated with production of secondary metabolites. Analysis of 12 microarrays monitoring gene expression of Aspergillus flavus over various growth conditions
2013-09-19 | E-GEOD-28163 | biostudies-arrayexpress
Project description:Aspergillus flavus and A. oryzae represent two unique species predicted to have spent centuries in vastly different environments. A. flavus is an important opportunistic plant pathogen known for contaminating crops with the carcinogenic mycotoxin, aflatoxin and A. oryzae is a domesticated fungus used in food fermentations. Remarkably, the genomes of these two species are still nearly identical. We have used the recently sequenced genomes of A. oryzae RIB40 and A. flavus NRRL3357 along with array based comparative genome hybridization (CGH) as a tool to compare genomes across several strains of these two species. A comparison of three strains from each species by CGH revealed only 42 and 129 genes unique to A. flavus and A. oryzae, respectively. Further, only 709 genes were identified as being polymorphic between the species. Despite the high degree of similarity between these two species, correlation analysis among all data from the CGH arrays for all strains used in this study reveals a species split. However, this view of species demarcation becomes muddled when focused on only those genes for secondary metabolism. CGH comparison between 3 strains of A. flavus and 3 strains of A. oryzae, analyzed at the probe level
2010-04-10 | E-GEOD-15650 | biostudies-arrayexpress
Project description:Aspergillus flavus and A. oryzae represent two unique species predicted to have spent centuries in vastly different environments. A. flavus is an important opportunistic plant pathogen known for contaminating crops with the carcinogenic mycotoxin, aflatoxin and A. oryzae is a domesticated fungus used in food fermentations. Remarkably, the genomes of these two species are still nearly identical. We have used the recently sequenced genomes of A. oryzae RIB40 and A. flavus NRRL3357 along with array based comparative genome hybridization (CGH) as a tool to compare genomes across several strains of these two species. A comparison of three strains from each species by CGH revealed only 42 and 129 genes unique to A. flavus and A. oryzae, respectively. Further, only 709 genes were identified as being polymorphic between the species. Despite the high degree of similarity between these two species, correlation analysis among all data from the CGH arrays for all strains used in this study reveals a species split. However, this view of species demarcation becomes muddled when focused on only those genes for secondary metabolism.
2010-04-10 | GSE15650 | GEO
Project description:To better understand the effect of temperature on mycotoxin biosynthesis, RNA-Seq technology was used to profile the Aspergillus flavus transcriptome under different temperature conditions. This approachallowed us to quantify transcript abundance for over 80% of fungal genes including 1,153 genes that were differentially expressed at 30°C and 37°C. Wleven of the 55 secondary metabolite clusters were up-regulated at the lower temperature, including aflatoxin biosynthesis genes, which were among the most highly up-expressed genes. On average, transcript abundance for the 30 aflatoxin biosynthesis genes was 3,300 times greater at 30°C as compared to 37°C. The results are consistent with the view that high temperature negatively affects aflatoxin production by turning down transcription of the two key transcriptional regulators, aflR and aflS. Subtle changes in the expression levels of aflS to aflR appear to control transcription activation of the aflatoxin cluster.
2011-06-16 | GSE30031 | GEO