Expression data from dormant and germinating conidia from Aspergillus niger.
Ontology highlight
ABSTRACT: Conidia of Aspergillus niger are characterized by a dormant state and are moderate stress-resistant. Upon contact with a moist substrate, germination of conidia occurs by changing from a dormant stabilized state towards a growing vegetative cell. The RNA expression levels of dormant conidia and conidia that were in various stages of germination were studied. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. This indicates that the distinct morphological changes that occur during germination are not correlated with the highest change in the transcriptome.
ORGANISM(S): Aspergillus niger Aspergillus niger CBS 513.88
Project description:Conidia of Aspergillus niger are characterized by a dormant state and are moderate stress-resistant. Upon contact with a moist substrate, germination of conidia occurs by changing from a dormant stabilized state towards a growing vegetative cell. The RNA expression levels of dormant conidia and conidia that were in various stages of germination were studied. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. This indicates that the distinct morphological changes that occur during germination are not correlated with the highest change in the transcriptome. Samples of germinating conidia of Aspergillus niger N402 were taken in triple at 0h (dormant), 2h, 4h, 6h and 8h after inoculation in CM.
Project description:Genome-wide analysis was performed to assess the transcriptional landscape of germinating A. niger conidia using GeneChips. The metabolism of storage compounds during conidial germination was also examined and compared to the transcript levels from associated genes. The transcriptome of dormant conidia was shown to be highly differentiated from that of germinating conidia and major changes in response to environmental shift occurred within the first hour of germination. The breaking of dormancy was associated with increased transcript levels of genes involved in the biosynthesis of proteins, RNA turnover and respiratory metabolism. Increased transcript levels of genes involved in metabolism of nitrate and proline at the onset of germination implies their use as sources of nitrogen. Dormant conidia contained transcripts of genes involved in fermentation, gluconeogenesis and the glyoxylate cycle. The presence of such transcripts in dormant conidia may indicate the generation of energy from non-carbohydrate substrates during starvation-induced conidiation or for maintenance purposes during dormancy. The immediate onset of metabolism of internal storage compounds after the onset of germination, and the presence of transcripts of relevant genes, suggest that conidia are primed for the onset of germination.
Project description:Genome-wide analysis was performed to assess the transcriptional landscape of germinating A. niger conidia using GeneChips. The metabolism of storage compounds during conidial germination was also examined and compared to the transcript levels from associated genes. The transcriptome of dormant conidia was shown to be highly differentiated from that of germinating conidia and major changes in response to environmental shift occurred within the first hour of germination. The breaking of dormancy was associated with increased transcript levels of genes involved in the biosynthesis of proteins, RNA turnover and respiratory metabolism. Increased transcript levels of genes involved in metabolism of nitrate and proline at the onset of germination implies their use as sources of nitrogen. Dormant conidia contained transcripts of genes involved in fermentation, gluconeogenesis and the glyoxylate cycle. The presence of such transcripts in dormant conidia may indicate the generation of energy from non-carbohydrate substrates during starvation-induced conidiation or for maintenance purposes during dormancy. The immediate onset of metabolism of internal storage compounds after the onset of germination, and the presence of transcripts of relevant genes, suggest that conidia are primed for the onset of germination. one biological replicate for each sample, each sample contained pooled RNA from three independent replicates
Project description:The impact of natamycin on Aspergillus niger was analysed during 8 h of germination of conidia. Polarization, germ tube formation, and mitosis were inhibited in the presence of 3 M-BM-5M and 10 M-BM-5M of the anti fungal compound natamycin, while at 10 M-BM-5M also isotropic growth was affected. Natamycin did not have an effect on the decrease of internal microviscosity and the concomitant reduction on mannitol and trehalose levels. However, it did abolish the increase of intracellular levels of glycerol and glucose during the 8 h period of germination. Natamycin hardly affected the changes that occur in the RNA profile during the first 2 h of germination. During this time period, genes related to transcription, protein synthesis, energy and cell cycle and DNA processing were particularly up regulated. On the other hand, when 8 h old germlings were compared, genes involved in ergosterol biosynthesis were down regulated while genes related to endocytosis and metabolism of compatible solutes, and genes encoding protective proteins were up regulated. Samples of germinating conidia of Aspergillus niger N402 were taken in triplo at 0h (dormant), 2h, and 8h after inoculation in CM. These were compared with conidia that germinated in the presence of either 3 M-BM-5M or 10 M-BM-5M natamycin.
Project description:The early stages of development of Aspergillus niger conidia during outgrowth were explored by combining genome-wide gene expression analysis (RNAseq), proteomics, Warburg manometry and uptake studies. Resting conidia were shown to be metabolically active as low levels of oxygen uptake and the generation of carbon dioxide were detected, suggesting that low-level respiratory metabolism occurs in conidia for maintenance. Upon triggering of spore germination, generation of CO2 started immediately. For a short period, which coincided with mobilisation of the intracellular polyol, trehalose, there was no increase in uptake of O2 indicating that trehalose was metabolised by fermentation. Data from genome-wide mRNA profiling showed the presence of transcripts associated with fermentative and respiratory metabolism in resting conidia. Following triggering of conidial outgrowth, there was a clear switch to respiration after 25 min, confirmed by cyanide inhibition. No effect of SHAM on respiration suggests electron flow via cytochrome c oxidase. Glucose entry into spores was not detectable before 1 h after triggering germination. Sub-inhibitory levels of sorbic acid delayed both the turnover of trehalose and the uptake of glucose. Oxygen uptake was also then inhibited, delaying the onset of respiration and extending the period of fermentation.
Project description:Genome-wide analysis was performed to assess the transcriptional landscape of germinating A. niger conidia for first hour using next generation RNA-sequencing. The transcriptome of dormant conidia was shown to be highly differentiated from that of germinating conidia. The breaking of dormancy was associated with increased transcript levels of genes involved in the biosynthesis of proteins, RNA turnover and respiratory metabolism. Increased transcript levels of genes involved in metabolism of nitrate and proline at the onset of germination implies their use as sources of nitrogen. The transcriptome of dormant conidia contained a significant component of antisense transcripts that changed during germination. Dormant conidia contained transcripts of genes involved in fermentation, gluconeogenesis and the glyoxylate cycle. The presence of such transcripts in dormant conidia may indicate the generation of energy from non-carbohydrate substrates during starvation-induced conidiation or for maintenance purposes during dormancy. The immediate onset of metabolism of internal storage compounds after the onset of germination, and the presence of transcripts of relevant genes, suggest that conidia are primed for the onset of germination. For some genes, antisense transcription is regulated in the transition from resting conidia to fully active germinants.
Project description:Genome-wide analysis was performed to assess the transcriptional landscape of germinating A. niger conidia for first hour using next generation RNA-sequencing. The transcriptome of dormant conidia was shown to be highly differentiated from that of germinating conidia. The breaking of dormancy was associated with increased transcript levels of genes involved in the biosynthesis of proteins, RNA turnover and respiratory metabolism. Increased transcript levels of genes involved in metabolism of nitrate and proline at the onset of germination implies their use as sources of nitrogen. The transcriptome of dormant conidia contained a significant component of antisense transcripts that changed during germination. Dormant conidia contained transcripts of genes involved in fermentation, gluconeogenesis and the glyoxylate cycle. The presence of such transcripts in dormant conidia may indicate the generation of energy from non-carbohydrate substrates during starvation-induced conidiation or for maintenance purposes during dormancy. The immediate onset of metabolism of internal storage compounds after the onset of germination, and the presence of transcripts of relevant genes, suggest that conidia are primed for the onset of germination. For some genes, antisense transcription is regulated in the transition from resting conidia to fully active germinants. Duplicate samples from each time point: dormant conidia T0 (DA 21 + DA 22) and conidia germinated for one hour T1 (DA 23 + DA 24)
Project description:The impact of natamycin on Aspergillus niger was analysed during 8 h of germination of conidia. Polarization, germ tube formation, and mitosis were inhibited in the presence of 3 µM and 10 µM of the anti fungal compound natamycin, while at 10 µM also isotropic growth was affected. Natamycin did not have an effect on the decrease of internal microviscosity and the concomitant reduction on mannitol and trehalose levels. However, it did abolish the increase of intracellular levels of glycerol and glucose during the 8 h period of germination. Natamycin hardly affected the changes that occur in the RNA profile during the first 2 h of germination. During this time period, genes related to transcription, protein synthesis, energy and cell cycle and DNA processing were particularly up regulated. On the other hand, when 8 h old germlings were compared, genes involved in ergosterol biosynthesis were down regulated while genes related to endocytosis and metabolism of compatible solutes, and genes encoding protective proteins were up regulated.
Project description:An Aspergillus niger colony can produce a few billion conidia. Formation of conidia producing conidiophores starts in the centre of the colony and moves outwards ending a few millimetres from the edge of the radial extending mycelium. As a result, the conidia within the colony centre are older than those in the intermediate and sub-peripheral zones. Here, it was assessed whether this results in heterogeneity of conidia within the colony. Conidia were harvested from conidiophores of cultures resulting from a confluent inoculated plate. A total number of 645-2421 genes were differentially expressed (fold change ≥ 2) when expression profiles of 2-, 5-, and 8-day-old conidia freshly harvested from conidiophores were compared. Genes without a PFAM or KEGG annotation were enriched in the up-regulated genes.
Project description:To establish the basis for understanding molecular mechanism of seed germination response to temperature, we analyzed transcriptomes in freshly harvested dormant and dry stored after-ripened seeds. The after-ripened seeds started to show visible germination from 36h after the start of imbibition, and almost all the seeds germinated after 3 days. The freshly harvested seeds stayed dormant by imbibition at 26°C, and germination of the after-ripened seeds was almost completely inhibited at 34°C. Total RNA was prepared from 0 (dry), 6 and 24h imbibed seeds to find regulatory genes of seed dormancy and germination.