Proteomic analysis of Fusarium graminearum treated by the fungicide JS399-19

Comparative transcriptome analysis of Fusarium graminearum challenged with distinct fungicides and functional analysis of FgICL gene

Fusarium graminearum is an economically important phytopathogenic fungus. Chemical control remains the dominant approach to managing this plant pathogen. In the present study, we performed a comparative transcriptome analysis to understand the effects of four commercially used fungicides on F. graminearum. The results revealed a significant number of differentially expressed genes related to carbohydrate, amino acid, and lipid metabolism, particularly in the carbendazim and phenamacril groups. Central carbon pathways, including the TCA and glyoxylate cycles, were found to play crucial roles across all treatments except tebuconazole. Weighted gene co-expression network analysis reinforced the pivotal role of central carbon pathways based on identified hub genes. Additionally, critical candidates associated with ATP-binding cassette transporters, heat shock proteins, and chitin synthases were identified. The crucial functions of the isocitrate lyase in F. graminearum were also validated. Overall, the study provided comprehensive insights into the mechanisms of how F. graminearum responds to fungicide stress.

Unravelling the effect of control agents on Gnomoniopsis smithogilvyi on a chestnut-based medium by proteomics

BACKGROUND

Gnomoniopsis smithogilvyi is the major chestnut pathogen, responsible for economic losses and recently described as a 3-nitropropionic acid and diplodiatoxin mycotoxin producer. Bacillus amyloliquefaciens QST 713 (Serenade® ASO), B. amyloliquefaciens CIMO-BCA1, and the fungicide Horizon® (tebuconazole) have been shown to reduce the growth of G. smithogilvyi. However, they enhanced mycotoxin production. Proteomics can clarify the mould's physiology and the impact of antifungal agents on the mould's metabolism. Thus, the aim of this study was to assess the impact of Horizon®, Serenade®, and B. amyloliquefaciens CIMO-BCA1 in the proteome of G. smithogilvyi to unveil their modes of action and decipher why the mould responds by increasing the mycotoxin production. For this, the mycelium close to the inhibition zone provoked by antifungals was macroscopically and microscopically observed. Proteins were extracted and analysed using a Q-Exactive plus Orbitrap.

RESULTS

The results did not elucidate specific proteins involved in the mycotoxin biosynthesis, but these agents provoked different kinds of stress on the mould, mainly affecting the cell wall structures and antioxidant response, which points to the mycotoxins overproduction as a defence mechanism. The biocontrol agent CIMO-BCA1 acts similar to tebuconazole. The results revealed different responses on the mould's metabolism when co-cultured with the two B. amyloliquefaciens, showing different modes of action of each bacterium, which opens the possibility of combining both biocontrol strategies.

CONCLUSION

These results unveil different modes of action of the treatments that could help to reduce the use of toxic chemicals to combat plant pathogens worldwide. © 2023 Society of Chemical Industry.

One-pot synthesis of 2D Ag/BiOCl/Bi2O2CO3 S-scheme heterojunction with oxygen vacancy for photocatalytic disinfection of Fusarium graminearum in vitro and in vivo

2D Ag/BiOCl/Bi₂O₂CO₃ S-scheme heterojunction was prepared with oxygen vacancy (OVs) via one-pot hydrothermal method. The XRD and XPS analysis indicated the synthesized sample contained Ag nanoparticles (AgNPs) instead of Ag ions. The SEM and HRTEM pictures showed that BiOCl/Bi₂O₂CO₃ nanosheets were modified with AgNPs. Compared with AgNPs, BiOCl, and Bi₂O₂CO₃, Ag/BiOCl/Bi₂O₂CO₃ exhibited highly photocatalytic inactivation of pathogenic fungi (Fusarium graminearum) due to the wide light absorption range and S-scheme heterojunction structure, which improved the production and transfer of photogenerated carrier, and enhanced the separation of photogenerated e-/h⁺ pairs. In addition, the improved photocatalytic disinfection against Fusarium graminearum of Ag/BiOCl/Bi₂O₂CO₃ was verified in Sedeveria Letizia plant. Furthermore, active species capture assay and ESR experiments disclosed the involvement of OVs, h⁺, ∙O₂^-, ∙OH, and ^-for Fusarium graminearum destruction during photocatalysis process. The S-scheme heterojunction was proved via oxygen vacancy, which was extensively beneficial to increase charge transmission and separation efficiency. Our work proposed Ag/BiOCl/Bi₂O₂CO₃ was an efficient and ecological fungicide to inactive Fusarium graminearum in vitro and vivo for crop disease.

Quantitative multiplexed proteomics analysis reveals reshaping of the lysine 2-hydroxyisobutyrylome in Fusarium graminearum by tebuconazole

Backgrounds

Lysine 2-hydroxyisobutyrylation (Khib) is a newly discovered posttranslational modification (PTM) and has been identified in several prokaryotic and eukaryotic organisms. Fusarium graminearum, a major pathogen of Fusarium head blight (FHB) in cereal crops, can cause considerable yield loss and produce various mycotoxins that threaten human health. The application of chemical fungicides such as tebuconazole (TEC) remains the major method to control this pathogen. However, the distribution of Khib in F. graminearum and whether Khib is remodified in response to fungicide stress remain unknown.

Results

Here, we carried out a proteome-wide analysis of Khib in F. graminearum, identifying the reshaping of the lysine 2-hydroxyisobutyrylome by tebuconazole, using the most recently developed high-resolution LC–MS/MS technique in combination with high-specific affinity enrichment. Specifically, 3501 Khib sites on 1049 proteins were identified, and 1083 Khib sites on 556 modified proteins normalized to the total protein content were changed significantly after TEC treatment. Bioinformatics analysis showed that Khib proteins are involved in a wide range of biological processes and may be involved in virulence and deoxynivalenol (DON) production, as well as sterol biosynthesis, in F. graminearum.

Conclusions

Here, we provided a wealth of resources for further study of the roles of Khib in the fungicide resistance of F. graminearum. The results enhanced our understanding of this PTM in filamentous ascomycete fungi and provided insight into the remodification of Khib sites during azole fungicide challenge in F. graminearum.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08372-4.

Proteomic analysis reveals that naturally produced citral can significantly disturb physiological and metabolic processes in the rice blast fungus Magnaporthe oryzae

Rice blast (Magnaporthe oryzae), a major fungal disease in rice producing areas all over the world as well as in China, seriously affects the safety of rice production. Citral, a mixture of Z/E and trans isomers, is a natural acycloid monoterpene compound with good bacteriostatic effect on rice blast. To further investigate the underlying molecular mechanism, a comparative proteomics analysis was conducted between citral-treated and non-treated M. oryzae spores through two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Our analysis identified 1600-1800 proteins from M. oryzae ZB15, of which 147 were differentially expressed in 100 μg/mL citral-treated samples relative to the control group. Among these differentially expressed proteins (DEPs), 40 proteins showed significantly different expression. GO enrichment and NCBI conserved domains database analysis showed that the main groups of the cellular component were cytoplasm (23.33%), and the major molecular function categories were ion binding (31.37%), and the major categories of biological processes included small molecule metabolic process (22.22%) and transport (13.89%). Further analysis found that down-regulated proteins included the tubulin α chain, ATP synthase subunit β and malate dehydrogenase, while the tubulin β, enolase were upregulated. These DEPs could possibly limit the availability of energy required for many cellular processes and result in various physiological adaptions of M. oryzae. This study represents the first proteomic analysis of M. oryzae treated by citral and will help to uncover the mode-of-action of this biologically active compound against M. oryzae. These findings have practical implications with respect to the use of citral for fungal disease control.

Cinnamaldehyde inhibits the growth of Phytophthora capsici through disturbing metabolic homoeostasis

Background

Phytophthora capsici Leonian (P. capsici) can cause wilting and roots rotting on pepper and other cash crops. The new fungicide cinnamaldehyde (CA) has high activity against this pathogen. However, its potential mechanism is still unknown.

Methods

In order to gain insights into the mechanism, isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomics was used to analyze P. capsici treated with CA. The iTRAQ results were evaluated by parallel reaction monitoring (PRM) analysis and quantitative real-time PCR (qRT-PCR) analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was used to speculate the biochemical pathways that the agent may act on.

Results

The results showed that 1502 differentially expressed proteins were identified, annotated and classified into 209 different terms (like metabolic process, cellular process, single-organism process) based on Gene Ontology (GO) functional enrichment analysis and nine different pathways (glyoxylate and dicarboxylate metabolism, fatty acid metabolism and so on) based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. This study suggested that CA disordered fatty acid metabolism, polysaccharide metabolism and leucine metabolism. Based on PRM analysis, five proteins including CAMK/CAMK1 protein kinase, glucan 1,3-beta-glucosidase, 1,3-beta-glucanosyltransferase, methylcrotonoyl-CoA carboxylase subunit alpha and isovaleryl-CoA dehydrogenase were down-regulated in P. capsici treated with CA. Furthermore, the qRT-PCR analysis showed that the gene expression level of the interested proteins was consistent with the protein expression level, except for CAMK/CAMK1 protein kinase, acetyl-CoA carboxylase and fatty acid synthase subunit alpha.

Conclusions

CA destroyed the metabolic homoeostasisof P. capsici, which led to cell death. This is the first proteomic analysis of P. capsici treated with CA, which may provide an important information for exploring the mechanism of the fungicide CA against P. capsici.

Undefeated-Changing the phenamacril scaffold is not enough to beat resistant Fusarium

Filamentous fungi belonging to the genus Fusarium are notorious plant-pathogens that infect, damage and contaminate a wide variety of important crops. Phenamacril is the first member of a novel class of single-site acting cyanoacrylate fungicides which has proven highly effective against important members of the genus Fusarium. However, the recent emergence of field-resistant strains exhibiting qualitative resistance poses a major obstacle for the continued use of phenamacril. In this study, we synthesized novel cyanoacrylate compounds based on the phenamacril-scaffold to test their growth-inhibitory potential against wild-type Fusarium and phenamacril-resistant strains. Our findings show that most chemical modifications to the phenamacril-scaffold are associated with almost complete loss of fungicidal activity and in vitro inhibition of myosin motor domain ATPase activity.

Proteomic analysis of the inhibitory effect of the butanolic fraction of Jacquinia macrocarpa on Fusarium verticillioides

Jacquinia macrocarpa, a plant native to northwestern Mexico, has an inhibitory effect against phytopathogenic fungi. Previous studies have shown that the butanolic extract of J. macrocarpa causes retardation and atrophy in mycelial growth of Fusarium verticillioides. However, the action mechanism of this extract is unknown. We used a proteomics approach to understand the inhibitory effect of J. macrocarpa butanolic extract, based on differential protein accumulation in F. verticillioides. Proteins were extracted from F. verticillioides cultured in Czapek broth with and without 202.12 μg/mL (IC₅₀) of butanolic extract of J. macrocarpa. Thirty-eight protein spots showing statistically significant changes (ANOVA, p < 0.01) and at least a 2-fold change in abundance between experimental conditions were analyzed by mass spectrometry. Identified proteins were grouped into different biological processes according to Gene Ontology, among them were amino acid metabolism, protein folding and stabilization, protein degradation, protein transport, carbohydrate metabolism, oxidative stress response, and miscellaneous. This work is the first report of changes in the proteomic profile of F. verticillioides exposed to the J. macrocarpa extract. This information provides new insights into the inhibitory mechanism of the extract and represents a starting point for dissection of the fungal response against the J. macrocarpa extract components.

Chemical Compositions of Propolis from China and the United States and their Antimicrobial Activities Against Penicillium notatum

The chemical compositions of ethanol extracts of propolis from China (EEP-C) and the United States (EEP-A) and their antifungal activity against Penicillium notatum were determined. The result showed that a total of 49 compounds were detected by UPLC-Q-TOF-MS, 30 of which were present in samples from two regions. The major compounds of EEP-C and EEP-A were similar, including pinocembrin, pinobanksin-3-O-acetate, galanin, chrysin, pinobanksin, and pinobanksin-methyl ether, and both of them showed antifungal activity against P. notatum with same minimum inhibitory concentration (MIC) value of 0.8 mg·mL-1. In the presence of propolis, the mycelial growth was inhibited, the hyphae became shriveled and wrinkled, the extracellular conductivities were increased, and the activities of succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) were decreased. In addition, iTRAQ-based quantitative proteomic analysis of P. notatum in response to propolis revealed that a total of 341 proteins were differentially expressed, of which 88 (25.8%) were upregulated and 253 (74.2%) were downregulated. Meanwhile, the differentially expressed proteins (DEPs) involved in energy production and conversion, carbohydrate transport and metabolism, and the sterol biosynthetic pathway were identified. This study revealed that propolis could affect respiration, interfere with energy metabolism, and influence steroid biosynthesis to inhibit the growth of P. notatum.

Insights from the proteome profile of Phytophthora capsici in response to the novel fungicide SYP-14288

Phytophthora capsica is a destructive oomycete plant pathogen that causes huge losses to crop production worldwide. However, the novel fungicide SYP-14288 has shown excellent activity against various stages of the oomycete life cycle as well against fungal plant pathogens. The current study utilized isobaric tags for relative and absolute quantitation technology to generate proteome profiles of P. capsici in the presence or absence of SYP-14288 in order to gain a greater understanding of the SYP-14288 mode of action. A total of 1,443 individual proteins were identified during the investigation, of which 599 were considered to have significantly altered expression. Further investigation using Cluster of Orthologous Groups of proteins analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated most of the proteins with altered expression were associated with carbohydrate metabolism, energy metabolism and their downstream biological functions, especially with regard to oxidoreductase activity and subsequent adenosine triphosphate (ATP) production associated pathways. Quantitative expression analysis using qRT-PCR validated the proteomic data. These results seem to indicate that SYP-14288 treatment caused a shift in energy metabolism that resulted in the activation of compensatory mechanisms affecting carbohydrate and lipid metabolism. The study also found evidence that the up-regulation of transmembrane transporters and proteins associated with stress response might also be coopted to compensate for the disrupted proton gradient and other downstream effects. Taken together these results provide strong evidence that SYP-14288 has a similar mode of action to the oxidative phosphorylation uncoupler Fluazinam but further investigation, including molecular studies, is required to completely characterize the SYP-14288 mode of action in P. capsici. However, the proteomic data collected in the current study does provide important insight into the overall effect of SYP-14288 in P. capsici, which could be useful for the registration and application of this novel fungicide.

Insights into the adaptive response of the plant-pathogenic oomycete Phytophthora capsici to the fungicide flumorph

Phytophthora capsici is an important oomycete plant pathogen that causes significant losses worldwide. The carboxylic acid amide fungicide flumorph has shown excellent activity against oomycete plant pathogens. Despite its potential, there remains concern that the sexual reproduction of oomycete pathogens, which results in genetic recombination, could result in the rapid development of resistance to flumorph. The current study utilized an iTRAQ (isobaric tags for relative and absolute quantitation) based method to compare differences between the proteome of the parental P. capsici isolate PCAS1 and its sexual progeny S2-838, which exhibits significant resistance to flumorph. A total of 2396 individual proteins were identified, of these, 181 were considered to be associated with the adaptive response of P. capsici to flumorph. The subsequent bioinformatic analysis revealed that the adaptive response of P. capsici to flumorph was complex and regulated by multiple mechanisms, including utilising carbohydrate from the host environment to compensate for the cell wall stress induced by flumorph, a shift in energy generation, decreased amino acids biosynthesis, and elevated levels of proteins associated with the pathogen's response to stimulus and transmembrane transport. Moreover, the results of the study provided crucial data that could provide the basis for early monitoring of flumorph resistance in field populations of P. capsici.

Proteomic analysis on zoxamide-induced sensitivity changes in Phytophthora cactorum

Zoxamide is an important fungicide for oomycete disease management. In this study, we established the baseline sensitivity of Phytophthora cactorum to zoxamide and assessed the risk of developing resistance to zoxamide using ultraviolet irradiation and fungicide taming methods. All 73 studied isolates were sensitive to zoxamide, with effective concentrations for 50% inhibition of mycelial growth ranging from 0.04 to 0.29 mg/L and mean of 0.15 mg/L. Stable zoxamide-resistant mutants of P. cactorum were not obtained from four arbitrarily selected isolates by either treating mycelial cultures with ultraviolet irradiation or adapting mycelial cultures to the addition of increasing zoxamide concentrations. However, the sensitivity of the isolates to zoxamide could be easily reduced by successive zoxamide treatments. In addition to displaying decreased sensitivity to zoxamide, these isolates also showed decreased sensitivity to the fungicides flumorph and cymoxanil. Proteomic analysis indicated that some proteins involved in antioxidant detoxification, ATP-dependent multidrug resistance, and anti-apoptosis activity, are likely responsible for the induced decrease in the sensitivity of P. cactorum to zoxamide compared to controls. Further semi-quantitative PCR analysis demonstrated that the gene expression profiles of most of above proteins were consistent with the proteomic analysis. Based on the above results, P. cactorum shows low resistance risk to zoxamide; however, the fungicidal effect of zoxamide might be decreased due to induced resistance when this fungicide is continuously applied.

Effects of phenazine-1-carboxylic acid on the biology of the plant-pathogenic bacterium Xanthomonas oryzae pv. oryzae

Xanthomonas oryzae pv. oryzae (Xoo) is the casual agent of bacterial blight, which is one of the most serious diseases of rice. The antibiotic phenazine-1-carboxylic acid (PCA), which is primarily produced by Pseudomonas spp., was found and previously reported very effective against Xoo. However, the biological effects of PCA on Xoo remain unclear. In this study, we found that PCA increased the accumulation of reactive oxygen species (ROS) and reduced the activities of catalase (CAT) and superoxide dismutase (SOD) in Xoo. Xoo was more sensitive to H2O2 than Xanthomonas oryzae pv. oryzicola (Xoc), and had a much lower expression of CAT genes. In addition, proteomic analysis indicated that PCA inhibited carbohydrate metabolism and nutrient uptake in Xoo, and analysis of carbon source utilization further confirmed that carbohydrate metabolism in Xoo was repressed by PCA. In conclusion, PCA acted as a redox-cycling agent that disturbed the redox balance in Xoo and reduced CAT and SOD activities, resulting in higher accumulation of ROS, altered carbohydrate metabolism, and lower energy production and nutrient uptake. Moreover, a deficient antioxidant system in Xoo made it very sensitive to PCA.

Proteomic analysis of zoxamide-induced changes in Phytophthora cactorum

In this study, the global proteomic response of Phytophthora cactorum to zoxamide was evaluated using a two-dimensional gel electrophoresis (2-DE)-based proteomic approach. Among the 21 proteins identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS), four cytoskeleton-related proteins were down-regulated upon addition of zoxamide. Five detoxification metabolism enzymes, seven sugar metabolism proteins and one mitochondria-related protein were up-regulated by more than 2-fold in response to zoxamide. Taken together, these results suggest that zoxamide can decrease the expression of cytoskeleton-related proteins of P. cactorum, resulting in cell death; however, the up-regulation of detoxification metabolism-related enzymes may protect P. cactorum against zoxamide, and the up-regulation of proteins related to sugar metabolism and mitochondria may lead to the generation of more energy for detoxification metabolism. These data also suggest that proteomics may be useful not only in exploring the mode of action of fungicides but also for gaining insight into the resistance mechanisms that pathogens employ against fungicides.

FgFim, a key protein regulating resistance to the fungicide JS399-19, asexual and sexual development, stress responses and virulence in Fusarium graminearum

Fimbrin is an actin-bundling protein found in intestinal microvilli, hair cell stereocilia and fibroblast filopodia. Its homologue Sac6p has been shown to play a critical role in endocytosis and diverse cellular processes in Saccharomyces cerevisiae. FgFim from the wheat scab pathogenic fungus Fusarium graminearum strain Y2021A, which is highly resistant to the fungicide JS399-19, was identified by screening a mutant library generated by HPH-HSV-tk cassette-mediated integration. The functions of FgFim were evaluated by constructing a deletion mutant of FgFim, designated ΔFgFim-15. The deletion mutant exhibited a reduced rate of mycelial growth, reduced conidiation, delayed conidium germination, irregularly shaped hyphae, a lack of sexual reproduction on autoclaved wheat kernels and a dramatic decrease in resistance to JS399-19. ΔFgFim-15 also exhibited increased sensitivity to diverse metal cations, to agents that induce osmotic stress and oxidative stress, and to agents that damage the cell membrane and cell wall. Pathogenicity assays showed that the virulence of the FgFim deletion mutant on flowering wheat heads was impaired, which was consistent with its reduced production of the toxin deoxynivalenol in host tissue. All of these defects were restored by genetic complementation of the mutant with the parental FgFim gene. Quantitative real-time polymerase chain reaction (PCR) assays showed that the basal expression of three Cyp51 genes, which encode sterol 14α-demethylase, was significantly lower in the mutant than in the parental strain. The results of this study indicate that FgFim plays a critical role in the regulation of resistance to JS399-19 and in various cellular processes in F. graminearum.