Project description:Salicylic acid (SA) is one of the key signal molecules in regulating plant resistance to diverse pathogens. It is predominantly associated with resistance against biotrophic and hemibiotrophic pathogens, and triggering systemic acquired resistance (SAR) in Arabidopsis. However, whether and how SA directly affects Fusarium graminearum and how SA influences the defence efficiency of wheat against fusarium head blight (FHB) are still poorly understood. Previous experiments have shown that the growth of F. graminearum mycelia and the germination of spores were significantly inhibited, and eventually stopped by increasing amounts of SA in both liquid and solid media cultures. Co-inoculation of SA and Fg spores has led to reduced FHB symptoms in the very susceptible Triticum aestivum cultivar ‘Roblin’. To better understand the effect of SA on F. graminearum mycelial growth, we have compared the expression profiles of SA-treated and untreated F. graminearum liquid cultures after 8 and 24 h of treatment, using an F. graminearum custom-commercial microarray. The microarray analysis suggests that F. graminearum can metabolize SA through two pathways, the gentisate and catechol pathways that are present in many fungal species. Additional experiments have confirmed the capacity of F. graminearum to metabolize SA. Our results demonstrate that, although F. graminearum has the capacity to metabolize SA, SA has a significant and direct impact on F. graminearum through a reduction in efficiency of germination and growth at higher concentrations. Untreated and Salicylic Acid (SA) treated liquid cultures of F. graminearum at 8h and 24h collection times. Three biological replicates per time point and treatment, 2 technical replicates (dye flips) per sample.
Project description:Fusarium graminearum and F. verticillioides are devastating cereal pathogens with very different life history and ecological characteristics. F. graminearum is homothallic, and sexual spores are an important component of its life cycle, responsible for disease initiation. F. verticilloides is heterothallic, and produces only modest numbers of fruiting bodies, which are not a significant source of inoculum. To identify corresponding differences in the transcriptional program underlying fruiting body development in the two species, comparative expression was performed, analyzing six developmental stages. To accompany the transcriptional analysis, detailed morphological characterization of F. verticillioides development was performed and compared to a previous morphological analysis of F. graminearum. Morphological development was similar between the two species, except for the observation of possible trichogynes in F. verticillioides ascogonia, which have not been previously reported for any Fusarium species. Expression of over 9000 orthologous genes were measured for the two species. Functional assignments of highly expressed orthologous genes at each time-point revealed the majority of highly expressed genes fell into the M-bM-^@M-^XM-bM-^@M-^Xunclassified proteinsM-bM-^@M-^YM-bM-^@M-^Y category, reflecting the lack of characterization of genes for sexual development in both species. Simultaneous examination of morphological development and stage-specific gene expression suggests that degeneration of the paraphyses during sexual development is an apoptotic process. Expression of mating type genes in the two species differed, possibly reflecting the divergent roles they play in sexual development. Overall, the differences in gene expression reflect the greater role of fruiting bodies in the life cycle and ecology of F. graminearum versus F. verticillioides. mRNA were sampled and compared from six time points across sexual reproduction in two Fusarium species
Project description:Salicylic acid (SA) is one of the key signal molecules in regulating plant resistance to diverse pathogens. It is predominantly associated with resistance against biotrophic and hemibiotrophic pathogens, and triggering systemic acquired resistance (SAR) in Arabidopsis. However, whether and how SA directly affects Fusarium graminearum and how SA influences the defence efficiency of wheat against fusarium head blight (FHB) are still poorly understood. Previous experiments have shown that the growth of F. graminearum mycelia and the germination of spores were significantly inhibited, and eventually stopped by increasing amounts of SA in both liquid and solid media cultures. Co-inoculation of SA and Fg spores has led to reduced FHB symptoms in the very susceptible Triticum aestivum cultivar ‘Roblin’. To better understand the effect of SA on F. graminearum mycelial growth, we have compared the expression profiles of SA-treated and untreated F. graminearum liquid cultures after 8 and 24 h of treatment, using an F. graminearum custom-commercial microarray. The microarray analysis suggests that F. graminearum can metabolize SA through two pathways, the gentisate and catechol pathways that are present in many fungal species. Additional experiments have confirmed the capacity of F. graminearum to metabolize SA. Our results demonstrate that, although F. graminearum has the capacity to metabolize SA, SA has a significant and direct impact on F. graminearum through a reduction in efficiency of germination and growth at higher concentrations.
Project description:Fusarium graminearum and F. verticillioides are devastating cereal pathogens with very different life history and ecological characteristics. F. graminearum is homothallic, and sexual spores are an important component of its life cycle, responsible for disease initiation. F. verticilloides is heterothallic, and produces only modest numbers of fruiting bodies, which are not a significant source of inoculum. To identify corresponding differences in the transcriptional program underlying fruiting body development in the two species, comparative expression was performed, analyzing six developmental stages. To accompany the transcriptional analysis, detailed morphological characterization of F. verticillioides development was performed and compared to a previous morphological analysis of F. graminearum. Morphological development was similar between the two species, except for the observation of possible trichogynes in F. verticillioides ascogonia, which have not been previously reported for any Fusarium species. Expression of over 9000 orthologous genes were measured for the two species. Functional assignments of highly expressed orthologous genes at each time-point revealed the majority of highly expressed genes fell into the ‘‘unclassified proteins’’ category, reflecting the lack of characterization of genes for sexual development in both species. Simultaneous examination of morphological development and stage-specific gene expression suggests that degeneration of the paraphyses during sexual development is an apoptotic process. Expression of mating type genes in the two species differed, possibly reflecting the divergent roles they play in sexual development. Overall, the differences in gene expression reflect the greater role of fruiting bodies in the life cycle and ecology of F. graminearum versus F. verticillioides.
Project description:The plant pathogenic fungus Fusarium graminearum (Fgr) creates economic and health risks in cereals agriculture. Fgr causes head blight (or scab) of wheat and stalk rot of corn, reducing yield, degrading grain quality and polluting downstream food products with mycotoxins. Fungal plant pathogens must secrete proteases to access nutrition and to breakdown the structural protein component of the plant cell wall. Research into the proteolytic activity of Fgr is hindered by the complex nature of the suite of proteases secreted. We used a systems biology approach comprising genome analysis, transcriptomics and label-free quantitative proteomics to characterise the peptidases deployed by Fgr during growth. A combined analysis of published microarray transcriptome datasets revealed seven transcriptional groupings of peptidases based on in vitro growth, in planta growth, and sporulation behaviours. An orbitrap MS/MS proteomics technique defined the extracellular proteases secreted by Fusarium graminearum.
Project description:The plant pathogenic fungus Fusarium graminearum (Fgr) creates economic and health risks in cereals agriculture. Fgr causes head blight (or scab) of wheat and stalk rot of corn, reducing yield, degrading grain quality and polluting downstream food products with mycotoxins. Fungal plant pathogens must secrete proteases to access nutrition and to breakdown the structural protein component of the plant cell wall. Research into the proteolytic activity of Fgr is hindered by the complex nature of the suite of proteases secreted. We used a systems biology approach comprising genome analysis, transcriptomics and label-free quantitative proteomics to characterise the peptidases deployed by Fgr during growth. A combined analysis of published microarray transcriptome datasets revealed seven transcriptional groupings of peptidases based on in vitro growth, in planta growth, and sporulation behaviours. An orbitrap MS/MS proteomics technique defined the extracellular proteases secreted by Fusarium graminearum. This dataset includes the cellular control sample that was analysed with shotgun mass-spec proteomics followed SearchGUI and Peptide shaker searches.
Project description:Bacterial pathogen Burkholderia glumae and fungal pathogen Fusarium graminearum cause similar disease symptoms and are often co-isolated from rice heads, inferring interactions between the two pathogens. F. graminearum is resistant to the bacterial toxin toxoflavin, a strong anti-microbial activity, produced by B. glumae. We isolated a toxoflavin-sensitive mutant from transcription factor deletion mutant library of F. graminearum. To understand genome-wide transcriptional profiling, we performed RNA-seq analyses of F. graminearum wild-type strain GZ03639 and toxoflavin-sensitive mutant strain, ∆GzZC190, under toxoflavin condition.
Project description:Bacterial pathogen Burkholderia glumae and fungal pathogen Fusarium graminearum cause similar disease symptoms and often co-isolated from rice heads, inferring interactions between the two pathogens. F. graminearum is resistant to the bacterial toxin toxoflavin, a strong anti-microbial activity, produced by B. glumae. We isolated toxoflavin-sensitive mutants from transcription factor deletion mutant library of F. graminearum. To understand genome-wide transcriptional profiling, we performed RNA-seq analyses of F. graminearum wild-type strain GZ03639 and toxoflavin-sensitive mutant strains (∆GzZC190, ∆GzC2H008, ∆GzbZIP005) under toxoflavin condition.
Project description:Fusarium head blight (FHB), caused by Fusarium graminearum, is a detrimental disease that affects small grains such as wheat around the world. Management of FHB is difficult, and improved methods of surveillance as well as a better understanding of pathogen aggressiveness are needed for improved control. F. graminearum disease severity varies depending on the resistance of the host genotype. In this study, we used the field pathogenomics method to investigate gene expression and population structure of isolates collected from wheat lines of varying resistance levels (susceptible, intermediate, and resistant) as well as an axenic control. Differential gene expression was found among isolates collected from different host genotypes. Candidate gene sets were identified for both F. graminearum infection of specific host genotypes and general infection to wheat. Population structure of isolates from different resistance level sources was the same, with all isolates belonging to the NA1 population.