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The worldwide occurrence of wheat crown rot, predominantly caused by the pathogen Fusarium pseudograminearum, has a serious impact on wheat production. Numerous microorganisms have been employed as biocontrol agents, exhibiting effectiveness in addressing a wide array of plant pathogens through various pathways. The mycelium of the white-rot fungus Phanerochaete chrysosporium effectively inhibits the growth of F. pseudograminearum by tightly attaching to it and forming specialized penetrating structures. This process leads to the release of intracellular inclusions and the eventual disintegration of pathogen cells. Furthermore, volatile organic compounds and fermentation products produced by P. chrysosporium exhibit antifungal properties. A comprehensive understanding of the mechanisms and modalities of action will facilitate the advancement and implementation of this biocontrol fungus. In order to gain a deeper understanding of the mycoparasitic behavior of P. chrysosporium, transcriptome analyses were conducted to examine the interactions between P. chrysosporium and F. pseudograminearum at 36, 48, and 84 h. During mycoparasitism, the up-regulation of differentially expressed genes (DEGs) encoding fungal cell-wall-degrading enzymes (CWDEs), iron ion binding, and mycotoxins were mainly observed. Moreover, pot experiments revealed that P. chrysosporium not only promoted the growth and quality of wheat but also hindered the colonization of F. pseudograminearum in wheat seedlings. This led to a delay in the development of stem base rot, a reduction in disease severity and incidence, and the activation of the plant's self-defense mechanisms. Our study provides important insights into the biocontrol mechanisms employed by P. chrysosporium against wheat crown rot caused by F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum causes destructive crown disease in wheat. The velvet protein family is a crucial regulator in development, virulence, and secondary metabolism of fungi. We conducted a functional analysis of FpVelB using a gene replacement strategy. The deletion of FpVelB decreased radial growth and enhanced conidial production compared to that of wild type. Furthermore, FpVelB modulates the fungal responses to abiotic stress through diverse mechanisms. Significantly, virulence decreased after the deletion of FpVelB in both the stem base and head of wheat. Genome-wide gene expression profiling revealed that the regulation of genes by FpVelB is associated with several processes related to the aforementioned phenotype, including "immune", "membrane", and "antioxidant activity", particularly with regard to secondary metabolites. Most importantly, we demonstrated that FpVelB regulates pathogen virulence by influencing deoxynivalenol production and modulating the expression of the PKS11 gene. In conclusion, FpVelB is crucial for plant growth, asexual development, and abiotic stress response and is essential for full virulence via secondary metabolism in F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR) is an important and devastating disease of wheat (Triticum aestivum) caused by the fungus Fusarium pseudograminearum and related pathogens. Using two distinct susceptible cultivars, we investigated the isolation frequencies of F. pseudograminearum and quantified its biomass accumulation and the levels of the associated toxins deoxynivalenol (DON) and DON-3-glucoside (D3G) in inoculated field-grown wheat plants. We detected F. pseudograminearum in stem, peduncle, rachis, and husk tissues, but not in grains, whereas DON and D3G accumulated in stem, rachis, husk, and grain tissues. Disease severity was positively correlated with the frequency of pathogen isolation, F. pseudograminearum biomass, and mycotoxin levels. The amount of F. pseudograminearum biomass and mycotoxin contents in asymptomatic tissue of diseased plants were associated with the distance of the tissue from the diseased internode and the disease severity of the plant. Thus, apparently healthy tissue may harbor F. pseudograminearum and contain associated mycotoxins. This research helps clarify the relationship between F. pseudograminearum occurrence, F. pseudograminearum biomass, and mycotoxin accumulation in tissues of susceptible wheat cultivars with or without disease symptoms, providing information that can lead to more effective control measures. [ABSTRACT FROM AUTHOR]

ABSTRACT Fusarium pseudograminearum, a soil-borne fungus, is the cause of the devastating wheat disease known as wheat crown rot (WCR). The persistence of this pathogen in the soil and crop residues contributes to the increased occurrence and severity of WCR. Therefore, developing effective strategies to prevent and manage WCR is of great importance. In this study, we isolated a bacterial strain, designated as SR9, from the stem of wheat, that exhibited potent antagonistic effects against F. pseudograminearum, as well as the biocontrol efficacy of SR9 on WCR was quantified at 83.99% ± 0.11%. We identified SR9 as Pseudomonas khavaziana and demonstrated its potential as a plant probiotic. SR9 displayed broad-spectrum antagonism against other fungal pathogens, including Neurospora dictyophora, Botrytis californica, and Botryosphaeria dothidea. Whole-genome sequencing analysis revealed that SR9 harbored genes encoding various cell wall-degrading enzymes, cellulases, and lipases, along with antifungal metabolites, which are responsible for its antagonistic activity. Gene knockout and quantitative PCR analyses reveal that phenazine is the essential factor for antagonism. SR9 possessed genes related to auxin synthesis, flagellar biosynthesis, biofilm adhesion, and the chemotaxis system, which play pivotal roles in plant colonization and growth promotion; we also evaluated the effects of SR9 on plant growth in wheat and Arabidopsis. Our findings strongly suggest that SR9 holds great promise as a biocontrol agent for WCR in sustainable agriculture.IMPORTANCEThe escalating prevalence of wheat crown rot, primarily attributed to Fusarium pseudograminearum, necessitates the development of cost-effective and eco-friendly biocontrol strategies. While plant endophytes are recognized for their biocontrol potential, reports on effective strains targeting wheat crown rot are sparse. This study introduces the Pseudomonas khavaziana SR9 strain as an efficacious antagonist to the wheat crown rot pathogen Fusarium pseudograminearum. Demonstrating a significant reduction in wheat crown rot incidence and notable plant growth promotion, SR9 emerges as a key contributor to plant health and agricultural sustainability. Our study outlines a biological approach to tackle wheat crown rot, establishing a groundwork for innovative sustainable agricultural practices.

Fusarium crown rot (FCR) in wheat is a prevalent soil-borne disease worldwide and poses a significant threat to the production of wheat (Triticum aestivum) in China, with F. pseudograminearum being the dominant pathogen. Currently, there is a shortage of biocontrol resources to control FCR induced by F. pseudograminearum, along with biocontrol mechanisms. In this study, we have identified 37 strains of biocontrol bacteria displaying antagonistic effects against F. pseudograminearum from over 8000 single colonies isolated from soil samples with a high incidence of FCR. Among them, QY43 exhibited remarkable efficacy in controlling FCR. Further analysis identified the isolate QY43 as Pseudomonas aeruginosa, based on its colony morphology and molecular biology. In vitro, QY43 significantly inhibited the growth, conidial germination, and the pathogenicity of F. pseudograminearum. In addition, QY43 exhibited a broad spectrum of antagonistic activities against several plant pathogens. The genomics analysis revealed that there are genes encoding potential biocontrol factors in the genome of QY43. The experimental results confirmed that QY43 secretes biocontrol factor siderophores and pyocyanin. In summary, QY43 exhibits a broad spectrum of antagonistic activities and the capacity to produce diverse biocontrol factors, thereby showing substantial potential for biocontrol applications to plant disease. [ABSTRACT FROM AUTHOR]

In China, Fusarium pseudograminearum has emerged as a major pathogen causing Fusarium crown rot (FCR) and caused significant losses. Studies on the pathogen's properties, especially its mating type and trichothecene chemotypes, are critical with respect to disease epidemiology and food/feed safety. There are currently few available reports on these issues. This study investigated the species composition, mating type idiomorphs, and trichothecene genotypes of Fusarium spp. causing FCR in Henan, China. A significant shift in F. pseudograminearum-induced FCR was found in the present study. Of the 144 purified strains, 143 were F. pseudograminearum, whereas only 1 Fusarium graminearum was identified. Moreover, a significant trichothecene-producing capability of F. pseudograminearum strains from Henan was observed in this work. Among the 143 F. pseudograminearum strains identified, F. pseudograminearum with a 15ADON genotype was found to be predominant (133 isolates), accounting for 92.36% of all strains, followed by F. pseudograminearum with a 3ADON genotype, whereas only one NIV genotype strain was detected. Overall, a relatively well-balanced 1:1 ratio of the F. pseudograminearum population was found in Henan. To the best of our knowledge, this is the first study that has examined the Fusarium populations responsible for FCR across the Henan wheat-growing region. [ABSTRACT FROM AUTHOR]

Abstract Background Fusarium crown rot (FCR) is one of the most significant diseases limiting crop production in the Huanghuai wheat-growing region of China. Prothioconazole, a triazole sterol 14α-demethylation inhibitor (DMI) fungicide developed by the Bayer Crop Protection Company, is mainly registered for the prevention and control of wheat powdery mildew and stripe rust (China Pesticide Information Network). It is known to exhibit high activity against F. pseudograminearum, but further research, particularly regarding the potential for fungicide resistance, is required before it can be registered for the control of FCR in China. Results The current study found that the baseline sensitivity of 67 field isolates of F. pseudograminearum collected between 2019 and 2021 ranged between 0.016–2.974 μg/mL, with an average EC50 value of 1.191 ± 0.720 μg/mL (mean ± SD). Although none of the field isolates exhibited signs of resistance, three highly resistant mutants were produced by repeated exposure to prothioconazole under laboratory conditions. All of the mutants were found to exhibit significantly reduced growth rates on potato dextrose agar (PDA), as well as reduced levels of sporulation, which indicated that there was a fitness cost associated with the resistance. However, inoculation of wounded wheat coleoptiles revealed that the pathogenicity of the resistant mutants was little affected or actually increased. Molecular analysis of the genes corresponding to the prothioconazole target protein, FpCYP51 (FpCYP51A, FpCYP51B, and FpCYP51C), indicated that the resistant mutants contained three conserved substitutions (M63I, A205S, and I246V) that were present in the FpCYP51C sequence of all three mutants, as well as several non-conserved substations in their FpCYP51A and FpCYP51B sequences. Expression analysis revealed that the presence of prothioconazole (0.1 μg/mL) generally resulted in reduced expression of the three FpCYP51 genes, but that the three mutants exhibited more complex patterns of expression that differed in comparison to their parental isolates. The study found no evidence of cross-resistance between prothioconazole and any of the fungicides tested including three DMI fungicides tebuconazole, prochloraz, and flutriafol. Conclusions Taken together these results not only provide new insight into the resistant mechanism and biological characteristics associated with prothioconazole resistance in F. pseudograminearum, but also strong evidence that prothioconazole could provide effective and sustained control of FCR, especially when applied in combination with other fungicides.

The worldwide occurrence of wheat crown rot, predominantly caused by the pathogen Fusarium pseudograminearum, has a serious impact on wheat production. Numerous microorganisms have been employed as biocontrol agents, exhibiting effectiveness in addressing a wide array of plant pathogens through various pathways. The mycelium of the white-rot fungus Phanerochaete chrysosporium effectively inhibits the growth of F. pseudograminearum by tightly attaching to it and forming specialized penetrating structures. This process leads to the release of intracellular inclusions and the eventual disintegration of pathogen cells. Furthermore, volatile organic compounds and fermentation products produced by P. chrysosporium exhibit antifungal properties. A comprehensive understanding of the mechanisms and modalities of action will facilitate the advancement and implementation of this biocontrol fungus. In order to gain a deeper understanding of the mycoparasitic behavior of P. chrysosporium, transcriptome analyses were conducted to examine the interactions between P. chrysosporium and F. pseudograminearum at 36, 48, and 84 h. During mycoparasitism, the up-regulation of differentially expressed genes (DEGs) encoding fungal cell-wall-degrading enzymes (CWDEs), iron ion binding, and mycotoxins were mainly observed. Moreover, pot experiments revealed that P. chrysosporium not only promoted the growth and quality of wheat but also hindered the colonization of F. pseudograminearum in wheat seedlings. This led to a delay in the development of stem base rot, a reduction in disease severity and incidence, and the activation of the plant’s self-defense mechanisms. Our study provides important insights into the biocontrol mechanisms employed by P. chrysosporium against wheat crown rot caused by F. pseudograminearum.

Fusarium crown rot (FCR) caused by Fusarium pseudograminearum is a serious threat to wheat production worldwide. This study aimed to assess the effects of Talaromyces muroii strain TM28 isolated from root of Panax quinquefolius against F. pseudograminearum. The strain of TM28 inhibited mycelial growth of F. pseudograminearum by 87.8% at 72 h, its cell free fermentation filtrate had a strong antagonistic effect on mycelial growth and conidial germination of F. pseudograminearum by destroying the integrity of the cell membrane. In the greenhouse, TM28 significantly increased wheat fresh weight and height in the presence of pathogen Fp, it enhanced the antioxidant defense activity and ameliorated the negative effects of F. pseudograminearum, including disease severity and pathogen abundance in the rhizosphere soil, root and stem base of wheat. RNAseq of F. pseudograminearum under TM28 antagonistic revealed 2,823 differentially expressed genes (DEGs). Most DEGs related to cell wall and cell membrane synthesis were significantly downregulated, the culture filtrate of TM28 affected the pathways of fatty acid synthesis, steroid synthesis, glycolysis, and the citrate acid cycle. T. muroii TM28 appears to have significant potential in controlling wheat Fusarium crown rot caused by F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Background: Fusarium crown rot (FCR) is one of the most significant diseases limiting crop production in the Huanghuai wheat-growing region of China. Prothioconazole, a triazole sterol 14α-demethylation inhibitor (DMI) fungicide developed by the Bayer Crop Protection Company, is mainly registered for the prevention and control of wheat powdery mildew and stripe rust (China Pesticide Information Network). It is known to exhibit high activity against F. pseudograminearum, but further research, particularly regarding the potential for fungicide resistance, is required before it can be registered for the control of FCR in China. Results: The current study found that the baseline sensitivity of 67 field isolates of F. pseudograminearum collected between 2019 and 2021 ranged between 0.016–2.974 μg/mL, with an average EC50 value of 1.191 ± 0.720 μg/mL (mean ± SD). Although none of the field isolates exhibited signs of resistance, three highly resistant mutants were produced by repeated exposure to prothioconazole under laboratory conditions. All of the mutants were found to exhibit significantly reduced growth rates on potato dextrose agar (PDA), as well as reduced levels of sporulation, which indicated that there was a fitness cost associated with the resistance. However, inoculation of wounded wheat coleoptiles revealed that the pathogenicity of the resistant mutants was little affected or actually increased. Molecular analysis of the genes corresponding to the prothioconazole target protein, FpCYP51 (FpCYP51A, FpCYP51B, and FpCYP51C), indicated that the resistant mutants contained three conserved substitutions (M63I, A205S, and I246V) that were present in the FpCYP51C sequence of all three mutants, as well as several non-conserved substations in their FpCYP51A and FpCYP51B sequences. Expression analysis revealed that the presence of prothioconazole (0.1 μg/mL) generally resulted in reduced expression of the three FpCYP51 genes, but that the three mutants exhibited more complex patterns of expression that differed in comparison to their parental isolates. The study found no evidence of cross-resistance between prothioconazole and any of the fungicides tested including three DMI fungicides tebuconazole, prochloraz, and flutriafol. Conclusions: Taken together these results not only provide new insight into the resistant mechanism and biological characteristics associated with prothioconazole resistance in F. pseudograminearum, but also strong evidence that prothioconazole could provide effective and sustained control of FCR, especially when applied in combination with other fungicides. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum causes destructive crown disease in wheat. The velvet protein family is a crucial regulator in development, virulence, and secondary metabolism of fungi. We conducted a functional analysis of FpVelB using a gene replacement strategy. The deletion of FpVelB decreased radial growth and enhanced conidial production compared to that of wild type. Furthermore, FpVelB modulates the fungal responses to abiotic stress through diverse mechanisms. Significantly, virulence decreased after the deletion of FpVelB in both the stem base and head of wheat. Genome-wide gene expression profiling revealed that the regulation of genes by FpVelB is associated with several processes related to the aforementioned phenotype, including “immune”, “membrane”, and “antioxidant activity”, particularly with regard to secondary metabolites. Most importantly, we demonstrated that FpVelB regulates pathogen virulence by influencing deoxynivalenol production and modulating the expression of the PKS11 gene. In conclusion, FpVelB is crucial for plant growth, asexual development, and abiotic stress response and is essential for full virulence via secondary metabolism in F. pseudograminearum.

Fusarium crown rot (FCR) in wheat is a prevalent soil-borne disease worldwide and poses a significant threat to the production of wheat (Triticum aestivum) in China, with F. pseudograminearum being the dominant pathogen. Currently, there is a shortage of biocontrol resources to control FCR induced by F. pseudograminearum, along with biocontrol mechanisms. In this study, we have identified 37 strains of biocontrol bacteria displaying antagonistic effects against F. pseudograminearum from over 8000 single colonies isolated from soil samples with a high incidence of FCR. Among them, QY43 exhibited remarkable efficacy in controlling FCR. Further analysis identified the isolate QY43 as Pseudomonas aeruginosa, based on its colony morphology and molecular biology. In vitro, QY43 significantly inhibited the growth, conidial germination, and the pathogenicity of F. pseudograminearum. In addition, QY43 exhibited a broad spectrum of antagonistic activities against several plant pathogens. The genomics analysis revealed that there are genes encoding potential biocontrol factors in the genome of QY43. The experimental results confirmed that QY43 secretes biocontrol factor siderophores and pyocyanin. In summary, QY43 exhibits a broad spectrum of antagonistic activities and the capacity to produce diverse biocontrol factors, thereby showing substantial potential for biocontrol applications to plant disease.

In China, Fusarium pseudograminearum has emerged as a major pathogen causing Fusarium crown rot (FCR) and caused significant losses. Studies on the pathogen’s properties, especially its mating type and trichothecene chemotypes, are critical with respect to disease epidemiology and food/feed safety. There are currently few available reports on these issues. This study investigated the species composition, mating type idiomorphs, and trichothecene genotypes of Fusarium spp. causing FCR in Henan, China. A significant shift in F. pseudograminearum-induced FCR was found in the present study. Of the 144 purified strains, 143 were F. pseudograminearum, whereas only 1 Fusarium graminearum was identified. Moreover, a significant trichothecene-producing capability of F. pseudograminearum strains from Henan was observed in this work. Among the 143 F. pseudograminearum strains identified, F. pseudograminearum with a 15ADON genotype was found to be predominant (133 isolates), accounting for 92.36% of all strains, followed by F. pseudograminearum with a 3ADON genotype, whereas only one NIV genotype strain was detected. Overall, a relatively well-balanced 1:1 ratio of the F. pseudograminearum population was found in Henan. To the best of our knowledge, this is the first study that has examined the Fusarium populations responsible for FCR across the Henan wheat-growing region.

The soil-borne pathogen Fusarium pseudograminearum is capable of causing a highly destructive crown disease in wheat. The purpose of this study was to characterize the biological functions, such as of virulence and secondary metabolites (SMs), of a putative RNA-Pol II transcription elongation factor, FpRtfA, in F. pseudograminearum. The current study revealed that the deletion of FpRtfA reduced radial growth compared to wild type in F. pseudograminearum. In addition, FpRtfA was found important to conidiation and response to metal ions and oxidative stress. More importantly, the virulence to the wheat stem base or head was decreased when FpRtfA was deleted. Using genome-wide gene expression profiling, FpRtfA was found to regulate several processes related to the above phenotype, such as the carbohydrate metabolic process, and the response to oxidative stress and oxidoreductase activity, especially for SMs. Further, we proved that FpRtfA exerts its regulatory effect on the virulence of pathogens by modulating the expression of the PKS gene, but not the generation of DON. In conclusion, FpRtfA has important roles in growth, asexual development, and the response to metal ions and oxidative stress. More importantly, FpRtfA is required for SMs and full virulence in F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR), mainly caused by Fusarium pseudograminearum, not only seriously threatens the yield and quality of wheat, but also endangers the health and safety of humans and livestock. Piriformospora indica is a root endophytic fungus that colonizes plant roots extensively and can effectively promote plant growth and improve plant resistance to biotic and abiotic stresses. In this study, the mechanism of FCR resistance mediated by P. indica in wheat was revealed from the phenylpropanoid metabolic pathway. The results showed that the colonization of P. indica significantly reduced the progression of wheat disease, the amount of F. pseudograminearum colonization, and the content of deoxynivalenol (DON) in wheat roots. RNA-seq suggested that P. indica colonization could reduce the number of differentially expressed genes (DEGs) in the transcriptome caused by F. pseudograminearum infection. The DEGs induced by the colonization of P. indica were partially enriched in phenylpropanoid biosynthesis. Transcriptome sequencing and qPCR indicated that the colonization of P. indica up-regulated the expression of genes involved in the phenylpropanoid biosynthesis pathway. The metabolome analysis indicated that the colonization of P. indica increased the metabolites' accumulation in the phenylpropanoid biosynthesis. Consistent with transcriptome and metabolomic analysis, microscopic observations showed enhanced lignin accumulation in the roots of the Piri and Piri+Fp lines, most likely contributing to the arrested infection by F. pseudograminearum. These results suggested that P. indica increased resistance to F. pseudograminearum in wheat by inducing the phenylpropanoid pathway. [ABSTRACT FROM AUTHOR]

Wheat crown rot, caused by Fusarium pseudograminearum, is an emerging soil-borne fungal disease and causes serious damage in areas where water is scarce. However, the interactions between plant, microbiome, and pathogen under different watering regimes are rarely known. In our study, we designed three watering patterns, including the early-drought (DR1), late-drought (DR2), and well-watered (WAT) patterns, and sampled at heading and grain filling, to investigate the effect of different watering regimes on the microbial community and disease severity. These findings showed that well-watered pattern at grain filling decreased the disease index compared to other patterns, and the bacterial community in the WAT and DR2 at grain filling showed higher alpha diversity (rhizosphere and root) and more stable structures (root). For the microbial network, irrespective of compartments, bacterial networks in the WAT and DR2 were more complex and connected with a higher average degree and clustering coefficient than DR1 at both periods. Furthermore, several potential beneficial microbes as biomarkers were enriched under good water conditions, specifically during the heading of DR2 and grain filling of WAT, including operational taxonomic units (OTUs) affiliated with the taxa of Arenimonas, Sphingomonas, Pseudoxanthomonas, Devosia, Lysobacter, Chitinophagaceae, and Gaiellales in the rhizosphere and root. Overall, the microbiome reshaped by good moisture or avoiding early drought should be emphasized and further used in controlling Fp-caused wheat crown rot. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR) caused by Fusarium pseudograminearum is one of the most serious soil-borne diseases of wheat. Among 58 bacterial isolates from the rhizosphere soil of winter wheat seedlings, strain YB-1631 was found to have the highest in vitro antagonism to F. pseudograminearum growth. LB cell-free culture filtrates inhibited mycelial growth and conidia germination of F. pseudograminearum by 84.14% and 92.23%, respectively. The culture filtrate caused distortion and disruption of the cells. Using a face-to-face plate assay, volatile substances produced by YB-1631 inhibited F. pseudograminearum growth by 68.16%. In the greenhouse, YB-1631 reduced the incidence of FCR on wheat seedlings by 84.02% and increased root and shoot fresh weights by 20.94% and 9.63%, respectively. YB-1631 was identified as Bacillus siamensis based on the gyrB sequence and average nucleotide identity of the complete genome. The complete genome was 4,090,312 bp with 4357 genes and 45.92% GC content. In the genome, genes were identified for root colonization, including those for chemotaxis and biofilm production, genes for plant growth promotion, including those for phytohormones and nutrient assimilation, and genes for biocontrol activity, including those for siderophores, extracellular hydrolase, volatiles, nonribosomal peptides, polyketide antibiotics, and elicitors of induced systemic resistance. In vitro production of siderophore, β-1, 3-glucanase, amylase, protease, cellulase, phosphorus solubilization, and indole acetic acid were detected. Bacillus siamensis YB-1631 appears to have significant potential in promoting wheat growth and controlling wheat FCR caused by F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Chaetomium globosum is a common plant endophytic fungi that exhibits great biocontrol potential in plant disease. Fusarium crown rot (FCR) is an important disease in wheat that seriously threatens wheat production worldwide. The control effect of C. globosum against wheat FCR remains unclear. In this study, we introduced an identified C. globosum 12XP1-2-3 and tested its biological control potential against wheat FCR. The hypha and fermentation broth exhibited an antagonistic effect against Fusarium pseudograminearum. Results from indoor experiments showed that C. globosum 12XP1-2-3 might delay the onset of symptoms of brown stem base and significantly reduced the disease index (37.3%). Field trials showed that wheat seeds coated with a spore suspension of 12XP1-2-3 grew better than the control seeds, had control effects of 25.9-73.1% on FCR disease, and increased wheat yield by 3.2-11.9%. Analysis of rhizosphere microorganisms revealed that seeds coated with C. globosum ('Cg' treatment) had a greater effect on fungal rather than on bacterial alpha diversity and may improve the health state of rhizosphere microorganisms, as reflected by the significantly increased fungal Shannon index at Feekes 11 and the increased complexity of the bacterial co-occurrence network but decreased complexity of the fungal network. Moreover, the accumulation of beneficial bacteria such as Bacillus and Rhizobium at Feekes 3, and Sphingomonas at Feekes 7 in the 'Cg' treatment may be the important contributions to healthier wheat growth state, significantly reduced relative abundance of Fusarium at Feekes 11, and reduced occurrence of FCR disease. These results provide a basis for further research on the mechanism of action of C. globosum and its application in the biological control of FCR in the field. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum is a major pathogen for the destructive disease Fusarium crown rot (FCR) of wheat (Triticum aestivum). The cytosolic Acetoacetyl-CoA thiolase II (AACT) is the first catalytic enzyme in the mevalonate pathway that biosynthesizes isoprenoids in plants. However, there has been no investigation of wheat cytosolic AACT genes in defense against pathogens including Fusarium pseudograminearum. Herein, we identified a cytosolic AACT-encoding gene from wheat, named TaAACT1, and demonstrated its positively regulatory role in the wheat defense response to F. pseudograminearum. One haplotype of TaAACT1 in analyzed wheat genotypes was associated with wheat resistance to FCR. The TaAACT1 transcript level was elevated after F. pseudograminearum infection, and was higher in FCR-resistant wheat genotypes than in susceptible wheat genotypes. Functional analysis indicated that knock down of TaAACT1 impaired resistance against F. pseudograminearum and reduced the expression of downstream defense genes in wheat. TaAACT1 protein was verified to localize in the cytosol of wheat cells. TaAACT1 and its modulated defense genes were rapidly responsive to exogenous jasmonate treatment. Collectively, TaAACT1 contributes to resistance to F. pseudograminearum through upregulating the expression of defense genes in wheat. This study sheds new light on the molecular mechanisms underlying wheat defense against FCR. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum has been identified as a significant pathogen. It causes Fusarium crown rot (FCR), which occurs in several major wheat-producing areas in China. Chemical control is the primary measure with which to control this disease. In this study, transcriptome sequencing (RNA-Seq) was used to determine the different mechanisms of action of four frequently used fungicides including carbendazim, pyraclostrobin, tebuconazole, and phenamacril on F. pseudograminearum. In brief, 381, 1896, 842, and 814 differentially expressed genes (DEGs) were identified under the carbendazim, pyraclostrobin, tebuconazole, and phenamacril treatments, respectively. After the joint analysis, 67 common DEGs were obtained, and further functional analysis showed that the ABC transported pathway was significantly enriched. Moreover, FPSE_04130 (FER6) and FPSE_11895 (MDR1), two important ABC multidrug transporter genes whose expression levels simultaneously increased, were mined under the different treatments, which unambiguously demonstrated the common effects. In addition, Mfuzz clustering analysis and WGCNA analysis revealed that the core DEGs are involved in several critical pathways in each of the four treatment groups. Taken together, these genes may play a crucial function in the mechanisms of F. pseudograminearum's response to the fungicides stress. [ABSTRACT FROM AUTHOR]

Sharp eyespot and Fusarium crown rot, mainly caused by soil-borne fungi Rhizoctonia cerealis and Fusarium pseudograminearum, are destructive diseases of major cereal crops including wheat (Triticum aestivum). However, the mechanisms underlying wheat-resistant responses to the two pathogens are largely elusive. In this study, we performed a genome-wide analysis of wall-associated kinase (WAK) family in wheat. As a result, a total of 140 TaWAK (not TaWAKL) candidate genes were identified from the wheat genome, each of which contains an N-terminal signal peptide, a galacturonan binding domain, an EGF-like domain, a calcium binding EGF domain (EGF-Ca), a transmembrane domain, and an intracellular Serine/Threonine protein kinase domain. By analyzing the RNA-sequencing data of wheat inoculated with R. cerealis and F. pseudograminearum, we found that transcript abundance of TaWAK-5D600 (TraesCS5D02G268600) on chromosome 5D was significantly upregulated, and that its upregulated transcript levels in response to both pathogens were higher compared with other TaWAK genes. Importantly, knock-down of TaWAK-5D600 transcript impaired wheat resistance against the fungal pathogens R. cerealis and F. pseudograminearum, and significantly repressed expression of defense-related genes in wheat, TaSERK1, TaMPK3, TaPR1, TaChitinase3, and TaChitinase4. Thus, this study proposes TaWAK-5D600 as a promising gene for improving wheat broad resistance to sharp eyespot and Fusarium crown rot (FCR) in wheat. [ABSTRACT FROM AUTHOR]

The cereal disease Fusarium crown rot (FCR), caused by the fungal pathogen Fusarium pseudograminearum (Fp), is a major constraint to cereal production worldwide. Nitrogen (N) fertilizer is estimated to be approximately 30% of the input costs for grain growers in Australia and is the primary driver of yield and grain protein levels. When targeting high yield and protein, generous nitrogen fertilizer applications are thought to result in large biomass production, which exacerbates FCR severity, reducing grain yield and quality. This research was undertaken to investigate the effect of temporal N availability in high-protein bread and durum wheat varieties on FCR severity. Laboratory and controlled environment experiments assessed the relationship between FCR and N at a mechanistic and plant level. An in vitro study demonstrated an increase in Fp mycelial growth under increased N availability, especially when N was supplied as urea compared with ammonium nitrate. Similarly, under controlled environmental conditions, increased soil N availability promoted FCR severity within infected plants. Stem N transfer efficiency was significantly decreased under FCR infection in both bread and durum wheat varieties by 4.5% and 10.2%, respectively. This new research demonstrates that FCR not only decreases yield and grain quality but appears to have previously unrecognised detrimental impacts on nitrogen-use efficiency in wheat. This indicates that the current impact of losses from FCR may also decrease N-use inefficiencies, as well as yield and quality penalties. An improved understanding of the interactions and restrictions of FCR infection may allow growers to better manage the disease through manipulation of the soil's temporal N availability. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR) on wheat is a soil-borne disease that affects the yield and quality of the produce. In 2020, 297 Fusarium pseudograminearum isolates were isolated from diseased FCR wheat samples from eight regional areas across Hebei Province in China. Baseline sensitivity of F. pseudograminearum to fludioxonil (0.0613 ± 0.0347 mg/mL) and tebuconazole (0.2328 ± 0.0840 mg/mL) were constructed based on the in vitro tests of 71 and 83 isolates, respectively. The resistance index analysis showed no resistance isolate to fludioxonil but two low-resistance isolates to tebuconazole in 2020. There was an increased frequency of resistant isolates from 2021 to 2022 based on the baseline sensitivity for tebuconazole. There was no cross-resistance between fludioxonil and tebuconazole. This study provides a significant theoretical and practical basis for monitoring the resistance of F. pseudograminearum to fungicides, especially the control of FCR. [ABSTRACT FROM AUTHOR]

Abstract Introduction Plant‐associated microorganisms are widely explored for their use as bioinoculants in agriculture. However, the rate and ability of introduced microbes to colonise and interact with indigenous soil microbiomes are largely unknown. Materials & Methods In this study, we constructed a bacterial synthetic community (SynCom) using eight plant‐growth‐promoting bacteria isolated from the wheat (Triticum aestivum) rhizosphere, including three Bacillus spp., two Acinebacter spp., an Enterobacter sp., a Xanthomonas sp. and a Burkholderia sp., which all showed multiple plant growth‐promoting effects including indole‐3‐acetic acid and ammonia production and fungal pathogen suppression. We inoculated this SynCom in a soil with reduced microbial diversity, and investigated the ability of the SynCom to colonise wheat plants, and interact with soil microbes in the presence or absence of a soil‐borne pathogen Fusarium pseudograminearum (Fp). Results We found that SynCom significantly increased the wheat plant growth, root development and biomass production. Fp load in soil was significantly reduced and plant survival rates increased following the SynCom inoculation. Soil microbial community structure was altered by the SynCom, and noticeably, relative abundance of Pseudomonas spp. was induced in the soil. Conclusion This study provides novel evidence that colonisation of a beneficial SynCom promotes plant growth and alters soil microbial community.

Fusarium crown rot (FCR) is a major limitation to the wheat (Triticum aestivum L.) industry in the inland Pacific Northwest, United States. Genetic resistance to FCR is poorly understood and major gene resistance is not available in adapted cultivars. Chemical control is ineffective and crop rotations, which disrupt cycles of the disease, are not feasible in the region’s precipitation-limited climate. Cultural control methods are the only realistic option for farmers who struggle to minimize the impact of this disease. It is well established that FCR is favored by moisture-limited environments and an oversupply of plant-available nitrogen in soil. Effects of the supply of phosphorus in soil have not been clearly delineated. We conducted a 2-year FCR experiment at two locations in the low-precipitation zone (

Reliable prediction of the risk of mycotoxin contamination in post-harvest wheat will aid in improvement of the quality and safety. To establish the relationship between Fusarium pseudograminearum mycotoxins and CO2 production, changes in their respective concentrations were monitored for the artificial contamination of wheat under different values of water activities (0.84 aw, 0.92 aw, and 0.97 aw) and temperatures (20 ℃, 25 ℃, and 30 ℃). Water activity played a significant role in all these processes. CO2 concentration together with moisture content and temperature were used as the main parameters to establish DON and ZEN contamination prediction models. The prediction accuracy for DON was 98.15 % (R2 = 0.990) and 90.74 % for ZEN (R2 = 0.982). These models were combined with T/RH/MC/CO2 multi-parameter integrated sensors to form an early warning system, which offers a great prospect to minimise the risk of DON/ZEN contamination in post-harvest wheat.

Fusarium crown rot (FCR) of wheat, an important soil-borne disease, presents a worsening trend year by year, posing a significant threat to wheat production. Fusarium pseudograminearum cv. b was reported to be the dominant pathogen of FCR in China. Peroxisomes are single-membrane organelles in eukaryotes that are involved in many important biochemical metabolic processes, including fatty acid β-oxidation. PEX11 is important proteins in peroxisome proliferation, while less is known in the fungus F. pseudograminearum. The functions of FpPEX11a, FpPEX11b, and FpPEX11c in F. pseudograminearum were studied using reverse genetics, and the results showed that FpPEX11a and FpPEX11b are involved in the regulation of vegetative growth and asexual reproduction. After deleting FpPEX11a and FpPEX11b, cell wall integrity was impaired, cellular metabolism processes including active oxygen metabolism and fatty acid β-oxidation were significantly blocked, and the production ability of deoxynivalenol (DON) decreased. In addition, the deletion of genes of FpPEX11a and FpPEX11b revealed a strongly decreased expression level of peroxisome-proliferation-associated genes and DON-synthesis-related genes. However, deletion of FpPEX11c did not significantly affect these metabolic processes. Deletion of the three protein-coding genes resulted in reduced pathogenicity of F. pseudograminearum. In summary, FpPEX11a and FpPEX11b play crucial roles in the growth and development, asexual reproduction, pathogenicity, active oxygen accumulation, and fatty acid utilization in F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Homeobox transcription factors have been implicated in filamentous growth, conidia formation and virulence in fungal pathogens. However, the presence of the homeobox gene family and their potential influence on pathogenesis in Fusarium pseudograminearum have not been investigated. F. pseudograminearum is an important plant pathogen that causes wheat and barley crown rot. In this study, we performed a genome-wide survey for F. pseudograminearum homeobox genes, and 11 FpHtfs were identified and characterized. Domain analyses revealed that all of these proteins contain a complete homeobox domain that contains three helices. Expression profiles of FpHtf genes at different pathogen stages showed that six FpHtf genes were induced during infection. Further, we generated and characterized FpHtf3 deletion mutants in F. pseudograminearum, showing it was essential for virulence. These results indicated that members of the homeobox gene family are likely involved in F. pseudograminearum pathogenicity. Our work also provides a useful foundation for further studies on the complexity and function of the homeobox gene family in F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum , a soil-borne fungus, is the cause of the devastating wheat disease known as wheat crown rot (WCR). The persistence of this pathogen in the soil and crop residues contributes to the increased occurrence and severity of WCR. Therefore, developing effective strategies to prevent and manage WCR is of great importance. In this study, we isolated a bacterial strain, designated as SR9, from the stem of wheat, that exhibited potent antagonistic effects against F. pseudograminearum , as well as the biocontrol efficacy of SR9 on WCR was quantified at 83.99% ± 0.11%. We identified SR9 as Pseudomonas khavaziana and demonstrated its potential as a plant probiotic. SR9 displayed broad-spectrum antagonism against other fungal pathogens, including Neurospora dictyophora , Botrytis californica , and Botryosphaeria dothidea . Whole-genome sequencing analysis revealed that SR9 harbored genes encoding various cell wall-degrading enzymes, cellulases, and lipases, along with antifungal metabolites, which are responsible for its antagonistic activity. Gene knockout and quantitative PCR analyses reveal that phenazine is the essential factor for antagonism. SR9 possessed genes related to auxin synthesis, flagellar biosynthesis, biofilm adhesion, and the chemotaxis system, which play pivotal roles in plant colonization and growth promotion; we also evaluated the effects of SR9 on plant growth in wheat and Arabidopsis . Our findings strongly suggest that SR9 holds great promise as a biocontrol agent for WCR in sustainable agriculture.IMPORTANCEThe escalating prevalence of wheat crown rot, primarily attributed to Fusarium pseudograminearum , necessitates the development of cost-effective and eco-friendly biocontrol strategies. While plant endophytes are recognized for their biocontrol potential, reports on effective strains targeting wheat crown rot are sparse. This study introduces the Pseudomonas khavaziana SR9 strain as an efficacious antagonist to the wheat crown rot pathogen Fusarium pseudograminearum . Demonstrating a significant reduction in wheat crown rot incidence and notable plant growth promotion, SR9 emerges as a key contributor to plant health and agricultural sustainability. Our study outlines a biological approach to tackle wheat crown rot, establishing a groundwork for innovative sustainable agricultural practices., Competing Interests: The authors declare no conflict of interest.

Fusarium pseudograminearum is one of the major fungal pathogens that cause Fusarium crown rot (FCR) worldwide and can lead to a substantially reduced grain yield and quality. Transcription factors play an important role in regulating growth and pathogenicity in plant pathogens. In this study, we identified a putative Zn(II)2Cys6 fungal-type domain-containing transcription factor and named it FpUme18. The expression of FpUME18 was induced during the infection of wheat by F. pseudograminearum. The ΔFpume18 deletion mutant showed defects in growth, conidial production, and conidial germination. In the responses to the cell wall, salt and oxidative stresses, the ΔFpume18 mutant inhibited the rate of mycelial growth at a higher rate compared with the wild type. The staining of conidia and mycelia with lipophilic dye FM4-64 revealed a delay in endocytosis when FpUME18 was deleted. FpUME18 also positively regulated the expression of phospholipid-related synthesis genes. The deletion of FpUME18 attenuated the pathogenicity of wheat coleoptiles. FpUME18 also participated in the production of the DON toxin by regulating the expression of TRI genes. Collectively, FpUme18 is required for vegetative growth, conidiation, stress response, endocytosis, and full virulence in F. pseudograminearum.

Fusarium crown rot (FCR), mainly caused by Fusarium pseudograminearum, not only seriously threatens the yield and quality of wheat, but also endangers the health and safety of humans and livestock. Piriformospora indica is a root endophytic fungus that colonizes plant roots extensively and can effectively promote plant growth and improve plant resistance to biotic and abiotic stresses. In this study, the mechanism of FCR resistance mediated by P. indica in wheat was revealed from the phenylpropanoid metabolic pathway. The results showed that the colonization of P. indica significantly reduced the progression of wheat disease, the amount of F. pseudograminearum colonization, and the content of deoxynivalenol (DON) in wheat roots. RNA-seq suggested that P. indica colonization could reduce the number of differentially expressed genes (DEGs) in the transcriptome caused by F. pseudograminearum infection. The DEGs induced by the colonization of P. indica were partially enriched in phenylpropanoid biosynthesis. Transcriptome sequencing and qPCR indicated that the colonization of P. indica up-regulated the expression of genes involved in the phenylpropanoid biosynthesis pathway. The metabolome analysis indicated that the colonization of P. indica increased the metabolites’ accumulation in the phenylpropanoid biosynthesis. Consistent with transcriptome and metabolomic analysis, microscopic observations showed enhanced lignin accumulation in the roots of the Piri and Piri+Fp lines, most likely contributing to the arrested infection by F. pseudograminearum. These results suggested that P. indica increased resistance to F. pseudograminearum in wheat by inducing the phenylpropanoid pathway.

Fusarium crown rot (FCR) caused by Fusarium pseudograminearum is one of the most serious soil-borne diseases of wheat. Among 58 bacterial isolates from the rhizosphere soil of winter wheat seedlings, strain YB-1631 was found to have the highest in vitro antagonism to F. pseudograminearum growth. LB cell-free culture filtrates inhibited mycelial growth and conidia germination of F. pseudograminearum by 84.14% and 92.23%, respectively. The culture filtrate caused distortion and disruption of the cells. Using a face-to-face plate assay, volatile substances produced by YB-1631 inhibited F. pseudograminearum growth by 68.16%. In the greenhouse, YB-1631 reduced the incidence of FCR on wheat seedlings by 84.02% and increased root and shoot fresh weights by 20.94% and 9.63%, respectively. YB-1631 was identified as Bacillus siamensis based on the gyrB sequence and average nucleotide identity of the complete genome. The complete genome was 4,090,312 bp with 4357 genes and 45.92% GC content. In the genome, genes were identified for root colonization, including those for chemotaxis and biofilm production, genes for plant growth promotion, including those for phytohormones and nutrient assimilation, and genes for biocontrol activity, including those for siderophores, extracellular hydrolase, volatiles, nonribosomal peptides, polyketide antibiotics, and elicitors of induced systemic resistance. In vitro production of siderophore, β-1, 3-glucanase, amylase, protease, cellulase, phosphorus solubilization, and indole acetic acid were detected. Bacillus siamensis YB-1631 appears to have significant potential in promoting wheat growth and controlling wheat FCR caused by F. pseudograminearum.

Wheat crown rot, caused by Fusarium pseudograminearum, is an emerging soil-borne fungal disease and causes serious damage in areas where water is scarce. However, the interactions between plant, microbiome, and pathogen under different watering regimes are rarely known. In our study, we designed three watering patterns, including the early-drought (DR1), late-drought (DR2), and well-watered (WAT) patterns, and sampled at heading and grain filling, to investigate the effect of different watering regimes on the microbial community and disease severity. These findings showed that well-watered pattern at grain filling decreased the disease index compared to other patterns, and the bacterial community in the WAT and DR2 at grain filling showed higher alpha diversity (rhizosphere and root) and more stable structures (root). For the microbial network, irrespective of compartments, bacterial networks in the WAT and DR2 were more complex and connected with a higher average degree and clustering coefficient than DR1 at both periods. Furthermore, several potential beneficial microbes as biomarkers were enriched under good water conditions, specifically during the heading of DR2 and grain filling of WAT, including operational taxonomic units (OTUs) affiliated with the taxa of Arenimonas, Sphingomonas, Pseudoxanthomonas, Devosia, Lysobacter, Chitinophagaceae, and Gaiellales in the rhizosphere and root. Overall, the microbiome reshaped by good moisture or avoiding early drought should be emphasized and further used in controlling Fp-caused wheat crown rot.

Yield losses are experienced in corn fields due to stalk and ear rot disease. The fungicides used against the disease can not show the desired effect and the problem of resistance arises over time. For this reason, it is necessary to develop new strategies in the control against the disease. In this study, it was aim to determine the inhibitory effects of essential oils of rosemary, black cumin, cumin and sandalwood, and ginger against Fusarium verticillioides and Fusarium pseudograminearum under in vitro conditions. The essential oils were applied in doses of 0.25, 0.5, 1, 2 and 4 µl mL-1. PDA medium free of essential oils was used as negative control and PDA medium containing commercial fungicide (80 g l-1 Triticonazole, 40 g l-1 Pyraclostrobin-BASF company) was used as positive control. The experiment was carried out in a randomized plot design with three replications. In addition, chemical content analysis of essential oils was determined by GC-MS method. As a result of the study, as the dose of rosemary, black cumin, sandalwood and ginger essential oils increased, their inhibitory effects against both pathogens increased, and these effects were found close to each other. While the highest inhibitory effect against F. verticillioides and F. pseudograminearum was detected in the positive control treatment of cumin essential oil, 82.1% and 78.9%, respectively, this effect was found to be 74.6% and 68.3% in 4 µl mL-1 dose, respectively. However, more detailed studies should be carried out with these essential oils under field conditions. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum is a soilborne, hemibiotrophic phytopathogenic fungus that causes Fusarium crown rot and Fusarium head blight in wheat. The basic leucine zipper proteins (bZIPs) are evolutionarily conserved transcription factors that play crucial roles in a range of growth and developmental processes and the responses to biotic and abiotic stresses. However, the roles of bZIP transcription factors remains unknown in F. pseudograminearum. In this study, a bZIP transcription factor Fpkapc was identified to localize to the nucleus in F. pseudograminearum. A mutant strain (Δfpkapc) was constructed to determine the role of Fpkapc in growth and pathogenicity of F. pseudograminearum. Transcriptomic analyses revealed that many genes involved in basic metabolism and oxidation-reduction processes were downregulated, whereas many genes involved in metal iron binding were upregulated in the Δfpkapc strain, compared with the wild type (WT). Correspondingly, the mutant had severe growth defects and displayed abnormal hyphal tips. Conidiation in the Fpkapc mutant was reduced, with more conidia in smaller size and fewer septa than in the WT. Also, relative to WT, the Δfpkapc strain showed greater tolerance to ion stress, but decreased tolerance to H2O2. The mutant caused smaller disease lesions on wheat and barley plants, but significantly increased TRI gene expression, compared with the WT. In summary, Fpkapc plays multiple roles in governing growth, development, stress responses, and virulence in F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Simple Summary: Biological control of plant diseases caused by fungal pathogens using antagonistic microorganisms including Bacilli has been considered to be an effective and safe alternative to chemical fungicides. Fusarium crown rot of wheat is a serious fungal disease affecting yield and grain quality. In this study, a newly isolated strain of Bacillus subtilis YB-15 from soil of wheat rhizosphere significantly inhibited Fusarium crown rot as well as improved growth of wheat seedlings. Multiple potential biocontrol and growth-promoting attributes of Bacillus subtilis YB-15 were determined in vitro and according to the whole genome sequencing analysis. Overall, the results demonstrated that Bacillus subtilis YB-15 has great potential for practical application in controlling plant fungal diseases and improving plant growth. Fusarium crown rot caused by Fusarium pseudograminearum is one of the most devastating diseases of wheat worldwide causing major yield and economic losses. In this study, strain YB-15 was isolated from soil of wheat rhizosphere and classified as Bacillus subtilis by average nucleotide identity analysis. It significantly reduced Fusarium crown rot with a control efficacy of 81.50% and significantly improved the growth of wheat seedlings by increasing root and shoot fresh weight by 11.4% and 4.2%, respectively. Reduced Fusarium crown rot may have been due to direct antagonism by the production of β-1, 3-glucanase, amylase, protease and cellulase, or by the ability of B. subtilis YB-15 to induce defense-related enzyme activities of wheat seedlings, both alone and in seedlings infected with F. pseudograminearum. Improved plant growth may be related to the ability of B. subtilis YB-15 to secrete indole acetic acid and siderophores, as well as to solubilize phosphorus. In addition, the genome of strain YB-15 was determined, resulting in a complete assembled circular genome of 4,233,040 bp with GC content of 43.52% consisting of 4207 protein-encoding genes. Sequencing the B. subtilis YB-15 genome further revealed genes for encoding carbohydrate-active enzymes, biosynthesis of various secondary metabolites, nutrient acquisition, phytohormone production, chemotaxis and motility, which could explain the potential of strain YB-15 to be plant growth-promoting bacteria and biological control agent. B. subtilis YB-15 appears to be a promising biocontrol agent against Fusarium crown rot as well as for wheat growth promotion. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum megabirnavirus 1 (FpgMBV1) was isolated from the hypovirulent strain FC136-2A of F. pseudograminearum as a novel double-stranded RNA mycovirus belonging to the family Megabirnaviridae. Here we examined the effects of FpgMBV1 on colony morphology and pathogenicity of F. pseudograminearum. Through hyphal tip culture, we obtained virus-free progeny of strain FC136-2A, referred to as FC136-2A-V–. FpgMBV1 was transferred horizontally to another virus-free strain, WZ-8A-HygR-V–. The progeny obtained through horizontal transfer was referred to as WZ-8A-HygR-V+. Colony morphology was similar between the FpgMBV1-positive and -negative strains. The ability to penetrate cellophane in vitro was lost, and pathogenicity on wheat plants was reduced significantly in the FpgMBV1-positive strains relative to the FpgMBV1-negative strains. Microscopic observations showed a 6-h delay in the formation of appressoria-like structures in FC136-2A relative to FC136-2A-V–. Mycelium extension was significantly longer in wheat coleoptiles infected by WZ-8A-HygR-V– than in that infected by WZ-8A-HygR-V+ at 12 and 20 h after inoculation (hai). In addition, expression of five genes that encode cell wall-degrading enzymes differed significantly between FpgMBV1-positive and -negative strains at 12 and 20 hai during early infection of wheat cells by conidia. This study provides evidence for the hypovirulence effect of FpgMBV1 on F. pseudograminearum and suggests that the underlying mechanism involves unsuccessful early infection and perhaps cell wall degradation. [ABSTRACT FROM AUTHOR]

Fusarium pseudograminearum causes crown rot in wheat. This study aimed to assess the effects of the bacterial strain QTH8 isolated from Cotinus coggygria rhizosphere soil against F. pseudograminearum. Bacterial strain QTH8 was identified as Bacillus halotolerans in accordance with the phenotypic traits and the phylogenetic analysis of 16S rDNA and gyrB gene sequence. Culture filtrates of bacterial strain QTH8 inhibited the mycelial growth of F. pseudograminearum and resulted in mycelial malformation such as tumor formation, protoplast condensation, and mycelial fracture. In addition, bacterial strain QTH8 also inhibited the mycelial growth of Hainesia lythri, Pestalotiopsis sp., Botrytis cinerea, Curvularia lunata, Phyllosticta theaefolia, Fusarium graminearum, Phytophthora nicotianae, and Sclerotinia sclerotiorum. The active compounds produced by bacterial strain QTH8 were resistant to pH, ultraviolet irradiation, and low temperature, and were relatively sensitive to high temperature. After 4 h exposure, culture filtrates of bacterial strain QTH8—when applied at 5%, 10%, 15%, 20%, 25%, and 30%—significantly reduced conidial germination of F. pseudograminearum. The coleoptile infection assay proved that bacterial strain QTH8 reduced the disease index of wheat crown rot. In vivo application of QTH8 to wheat seedlings decreased the disease index of wheat crown rot and increased root length, plant height, and fresh weight. Iturin, surfactin, and fengycin were detected in the culture extract of bacterial strain QTH8 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Bacterial strain QTH8 was identified for the presence of the ituC, bacA, bmyB, spaS, srfAB, fend, and srfAA genes using the specific polymerase chain reaction primers. B. halotolerans QTH8 has a vital potential for the sustainable biocontrol of wheat crown rot. [ABSTRACT FROM AUTHOR]

Abstract Background Fusarium crown rot is major disease in wheat. However, the wheat defense mechanisms against this disease remain poorly understood. Results Using tandem mass tag (TMT) quantitative proteomics, we evaluated a disease-susceptible (UC1110) and a disease-tolerant (PI610750) wheat cultivar inoculated with Fusarium pseudograminearum WZ-8A. The morphological and physiological results showed that the average root diameter and malondialdehyde content in the roots of PI610750 decreased 3 days post-inoculation (dpi), while the average number of root tips increased. Root vigor was significantly increased in both cultivars, indicating that the morphological, physiological, and biochemical responses of the roots to disease differed between the two cultivars. TMT analysis showed that 366 differentially expressed proteins (DEPs) were identified by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment in the two comparison groups, UC1110_3dpi/UC1110_0dpi (163) and PI610750_3dpi/PI610750_0dpi (203). It may be concluded that phenylpropanoid biosynthesis (8), secondary metabolite biosynthesis (12), linolenic acid metabolites (5), glutathione metabolism (8), plant hormone signal transduction (3), MAPK signaling pathway-plant (4), and photosynthesis (12) contributed to the defense mechanisms in wheat. Protein-protein interaction network analysis showed that the DEPs interacted in both sugar metabolism and photosynthesis pathways. Sixteen genes were validated by real-time quantitative polymerase chain reaction and were found to be consistent with the proteomics data. Conclusion The results provided insight into the molecular mechanisms of the interaction between wheat and F. pseudograminearum.

Sharp eyespot and Fusarium crown rot, mainly caused by soil-borne fungi Rhizoctonia cerealis and Fusarium pseudograminearum, are destructive diseases of major cereal crops including wheat (Triticum aestivum). However, the mechanisms underlying wheat-resistant responses to the two pathogens are largely elusive. In this study, we performed a genome-wide analysis of wall-associated kinase (WAK) family in wheat. As a result, a total of 140 TaWAK (not TaWAKL) candidate genes were identified from the wheat genome, each of which contains an N-terminal signal peptide, a galacturonan binding domain, an EGF-like domain, a calcium binding EGF domain (EGF-Ca), a transmembrane domain, and an intracellular Serine/Threonine protein kinase domain. By analyzing the RNA-sequencing data of wheat inoculated with R. cerealis and F. pseudograminearum, we found that transcript abundance of TaWAK-5D600 (TraesCS5D02G268600) on chromosome 5D was significantly upregulated, and that its upregulated transcript levels in response to both pathogens were higher compared with other TaWAK genes. Importantly, knock-down of TaWAK-5D600 transcript impaired wheat resistance against the fungal pathogens R. cerealis and F. pseudograminearum, and significantly repressed expression of defense-related genes in wheat, TaSERK1, TaMPK3, TaPR1, TaChitinase3, and TaChitinase4. Thus, this study proposes TaWAK-5D600 as a promising gene for improving wheat broad resistance to sharp eyespot and Fusarium crown rot (FCR) in wheat.

Fusarium pseudograminearum is a major pathogen for the destructive disease Fusarium crown rot (FCR) of wheat (Triticum aestivum). The cytosolic Acetoacetyl-CoA thiolase II (AACT) is the first catalytic enzyme in the mevalonate pathway that biosynthesizes isoprenoids in plants. However, there has been no investigation of wheat cytosolic AACT genes in defense against pathogens including Fusarium pseudograminearum. Herein, we identified a cytosolic AACT-encoding gene from wheat, named TaAACT1, and demonstrated its positively regulatory role in the wheat defense response to F. pseudograminearum. One haplotype of TaAACT1 in analyzed wheat genotypes was associated with wheat resistance to FCR. The TaAACT1 transcript level was elevated after F. pseudograminearum infection, and was higher in FCR-resistant wheat genotypes than in susceptible wheat genotypes. Functional analysis indicated that knock down of TaAACT1 impaired resistance against F. pseudograminearum and reduced the expression of downstream defense genes in wheat. TaAACT1 protein was verified to localize in the cytosol of wheat cells. TaAACT1 and its modulated defense genes were rapidly responsive to exogenous jasmonate treatment. Collectively, TaAACT1 contributes to resistance to F. pseudograminearum through upregulating the expression of defense genes in wheat. This study sheds new light on the molecular mechanisms underlying wheat defense against FCR.

Abstract C2H2 zinc finger transcription factors such as FlbC and Msn2, have broad regulatory roles in fungal growth and conidiation. In the present study, we cloned and characterized a C2H2 zinc finger transcription factor gene, FpCzf14, in the wheat pathogen Fusarium pseudograminearum. FpCzf14 was localized to the nuclei. The expression of FpCzf14 was significantly upregulated in conidia, suggesting that FpCzf14 might contribute to conidiation. Further analysis of the fpczf14-deleted mutant (Δfpczf14) demonstrated that it exhibited defect in conidiation, and this defect was restored in the complemented strain Δfpczf14-C expressing FpCzf14, demonstrating that FpCzf14 was essential for conidiation. Moreover, FpCzf14 was required for mycelial growth and pathogenicity of F. pseudograminearum. Microscopic observation results showed that Δfpczf14 produced only very few penetration pegs and invasive hyphae inside host tissues compared with WT and Δfpczf14-C. Additionally, results of reverse transcription quantitative PCR (RT-qPCR) showed that FpCzf14 regulated expression of several conidiation-related genes in F. pseudograminearum. In conclusion, FpCzf14, as a core regulatory gene in conidiation, provides new insights into the mechanism of conidiation in F. pseudograminearum.

The cereal disease Fusarium crown rot (FCR), caused by the fungal pathogen Fusarium pseudograminearum (Fp), is a major constraint to cereal production worldwide. Nitrogen (N) fertilizer is estimated to be approximately 30% of the input costs for grain growers in Australia and is the primary driver of yield and grain protein levels. When targeting high yield and protein, generous nitrogen fertilizer applications are thought to result in large biomass production, which exacerbates FCR severity, reducing grain yield and quality. This research was undertaken to investigate the effect of temporal N availability in high-protein bread and durum wheat varieties on FCR severity. Laboratory and controlled environment experiments assessed the relationship between FCR and N at a mechanistic and plant level. An in vitro study demonstrated an increase in Fp mycelial growth under increased N availability, especially when N was supplied as urea compared with ammonium nitrate. Similarly, under controlled environmental conditions, increased soil N availability promoted FCR severity within infected plants. Stem N transfer efficiency was significantly decreased under FCR infection in both bread and durum wheat varieties by 4.5% and 10.2%, respectively. This new research demonstrates that FCR not only decreases yield and grain quality but appears to have previously unrecognised detrimental impacts on nitrogen-use efficiency in wheat. This indicates that the current impact of losses from FCR may also decrease N-use inefficiencies, as well as yield and quality penalties. An improved understanding of the interactions and restrictions of FCR infection may allow growers to better manage the disease through manipulation of the soil’s temporal N availability.

Fusarium crown rot (FCR) is an important and devastating disease of wheat ( Triticum aestivum ) caused by the fungus Fusarium pseudograminearum and related pathogens. Using two distinct susceptible cultivars, we investigated the isolation frequencies of F. pseudograminearum and quantified its biomass accumulation and the levels of the associated toxins deoxynivalenol (DON) and DON-3-glucoside (D3G) in inoculated field-grown wheat plants. We detected F. pseudograminearum in stem, peduncle, rachis, and husk tissues, but not in grains, whereas DON and D3G accumulated in stem, rachis, husk, and grain tissues. Disease severity was positively correlated with the frequency of pathogen isolation, F. pseudograminearum biomass, and mycotoxin levels. The amount of F. pseudograminearum biomass and mycotoxin contents in asymptomatic tissue of diseased plants were associated with the distance of the tissue from the diseased internode and the disease severity of the plant. Thus, apparently healthy tissue may harbor F. pseudograminearum and contain associated mycotoxins. This research helps clarify the relationship between F. pseudograminearum occurrence, F. pseudograminearum biomass, and mycotoxin accumulation in tissues of susceptible wheat cultivars with or without disease symptoms, providing information that can lead to more effective control measures., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Xu, Shi, Liu, Li, Wang, Han, Liu, Wang, Liu, Fan, Wang, Feng, Song, Zhou and Xu.)

The soil-borne fungi Fusarium pseudograminearum and Rhizoctonia cerealis are the major pathogens for the economically important diseases Fusarium crown rot (FCR) and sharp eyespot of common wheat (Triticum aestivum), respectively. However, there has been no report on the broad resistance of wheat genes against both F. pseudograminearum and R. cerealis. In the current study, we identified TaWAK-6D , a wall-associated kinase (WAK) which is an encoding gene located on chromosome 6D, and demonstrated its broad resistance role in the wheat responses to both F. pseudograminearum and R. cerealis infection. TaWAK-6D transcript induction by F. pseudograminearum and R. cerealis was related to the resistance degree of wheat and the gene expression was significantly induced by exogenous pectin treatment. Silencing of TaWAK-6D compromised wheat resistance to F. pseudograminearum and R. cerealis , and repressed the expression of a serial of wheat defense-related genes. Ectopic expression of TaWAK-6D in Nicotiana benthamiana positively modulated the expression of several defense-related genes. TaWAK-6D protein was determined to localize to the plasma membrane in wheat and N. benthamiana. Collectively, the TaWAK-6D at the plasma membrane mediated the broad resistance responses to both F. pseudograminearum and R. cerealis in wheat at the seedling stage. This study, therefore, concludes that TaWAK-6D is a promising gene for improving wheat broad resistance to FCR and sharp eyespot. [ABSTRACT FROM AUTHOR]

The soil-borne fungi Fusarium pseudograminearum and Rhizoctonia cerealis are the major pathogens for the economically important diseases Fusarium crown rot (FCR) and sharp eyespot of common wheat (Triticum aestivum), respectively. However, there has been no report on the broad resistance of wheat genes against both F. pseudograminearum and R. cerealis. In the current study, we identified TaWAK-6D, a wall-associated kinase (WAK) which is an encoding gene located on chromosome 6D, and demonstrated its broad resistance role in the wheat responses to both F. pseudograminearum and R. cerealis infection. TaWAK-6D transcript induction by F. pseudograminearum and R. cerealis was related to the resistance degree of wheat and the gene expression was significantly induced by exogenous pectin treatment. Silencing of TaWAK-6D compromised wheat resistance to F. pseudograminearum and R. cerealis, and repressed the expression of a serial of wheat defense-related genes. Ectopic expression of TaWAK-6D in Nicotiana benthamiana positively modulated the expression of several defense-related genes. TaWAK-6D protein was determined to localize to the plasma membrane in wheat and N. benthamiana. Collectively, the TaWAK-6D at the plasma membrane mediated the broad resistance responses to both F. pseudograminearum and R. cerealis in wheat at the seedling stage. This study, therefore, concludes that TaWAK-6D is a promising gene for improving wheat broad resistance to FCR and sharp eyespot.

Fusarium crown rot (FCR) of wheat, an important soil-borne disease, presents a worsening trend year by year, posing a significant threat to wheat production. Fusarium pseudograminearum cv. b was reported to be the dominant pathogen of FCR in China. Peroxisomes are single-membrane organelles in eukaryotes that are involved in many important biochemical metabolic processes, including fatty acid β-oxidation. PEX11 is important proteins in peroxisome proliferation, while less is known in the fungus F. pseudograminearum. The functions of FpPEX11a, FpPEX11b, and FpPEX11c in F. pseudograminearum were studied using reverse genetics, and the results showed that FpPEX11a and FpPEX11b are involved in the regulation of vegetative growth and asexual reproduction. After deleting FpPEX11a and FpPEX11b, cell wall integrity was impaired, cellular metabolism processes including active oxygen metabolism and fatty acid β-oxidation were significantly blocked, and the production ability of deoxynivalenol (DON) decreased. In addition, the deletion of genes of FpPEX11a and FpPEX11b revealed a strongly decreased expression level of peroxisome-proliferation-associated genes and DON-synthesis-related genes. However, deletion of FpPEX11c did not significantly affect these metabolic processes. Deletion of the three protein-coding genes resulted in reduced pathogenicity of F. pseudograminearum. In summary, FpPEX11a and FpPEX11b play crucial roles in the growth and development, asexual reproduction, pathogenicity, active oxygen accumulation, and fatty acid utilization in F. pseudograminearum.

Heat shock protein Hsp104, a homolog of the bacterial chaperone ClpB and plant Hsp100, plays an essential part in the response to heat and various chemical agents in Saccharomyces cerevisiae. However, their functions remain largely unknown in plant fungal pathogens. Here, we report the identification and functional characterization of a plausible ortholog of yeast Hsp104 in Fusarium pseudograminearum, which we termed FpHsp104. Deletion mutant of FpHsp104 displayed severe defects in the resistance of heat shock during F. pseudograminearum mycelia and conidia when exposed to extreme heat. We also found that the protein showed dynamic localization to small particles under high temperature. However, no significant differences were detected in osmotic, oxidative, or cell wall stress responses between the wild-type and Δfphsp104 strains. Quantitative real-time PCR analysis showed that FpHsp104 was upregulated in the conidia, and disruption of FpHsp104 gene resulted in defects in conidia production, morphology, and germination. The transcript levels of conidiation-related genes of FpFluG, FpVosA, FpWetA, and FpAbaA were reduced in the Δfphsp104 mutant vs. the wild-type strain, but heat-shocked mRNA splicing repair was not affected in Δfphsp104. Moreover, Δfphsp104 mutant also showed attenuated virulence, but its DON synthesis was normal. These data from the first study of Hsp104 in F. pseudograminearum strongly suggest that FpHsp104 gene is an important element in the heat tolerance, development, and pathogenicity processes of F. pseudograminearum.

Heat shock protein Hsp104, a homolog of the bacterial chaperone ClpB and plant Hsp100, plays an essential part in the response to heat and various chemical agents in Saccharomyces cerevisiae. However, their functions remain largely unknown in plant fungal pathogens. Here, we report the identification and functional characterization of a plausible ortholog of yeast Hsp104 in Fusarium pseudograminearum , which we termed FpHsp104. Deletion mutant of FpHsp104 displayed severe defects in the resistance of heat shock during F. pseudograminearum mycelia and conidia when exposed to extreme heat. We also found that the protein showed dynamic localization to small particles under high temperature. However, no significant differences were detected in osmotic, oxidative, or cell wall stress responses between the wild-type and Δ fphsp104 strains. Quantitative real-time PCR analysis showed that FpHsp104 was upregulated in the conidia, and disruption of FpHsp104 gene resulted in defects in conidia production, morphology, and germination. The transcript levels of conidiation-related genes of FpFluG , FpVosA , FpWetA , and FpAbaA were reduced in the Δ fphsp104 mutant vs. the wild-type strain, but heat-shocked mRNA splicing repair was not affected in Δ fphsp104. Moreover, Δ fphsp104 mutant also showed attenuated virulence, but its DON synthesis was normal. These data from the first study of Hsp104 in F. pseudograminearum strongly suggest that FpHsp104 gene is an important element in the heat tolerance, development, and pathogenicity processes of F. pseudograminearum. [ABSTRACT FROM AUTHOR]

Fusarium crown rot caused by Fusarium pseudograminearum is one of the most devastating diseases of wheat worldwide causing major yield and economic losses. In this study, strain YB-15 was isolated from soil of wheat rhizosphere and classified as Bacillus subtilis by average nucleotide identity analysis. It significantly reduced Fusarium crown rot with a control efficacy of 81.50% and significantly improved the growth of wheat seedlings by increasing root and shoot fresh weight by 11.4% and 4.2%, respectively. Reduced Fusarium crown rot may have been due to direct antagonism by the production of β-1, 3-glucanase, amylase, protease and cellulase, or by the ability of B. subtilis YB-15 to induce defense-related enzyme activities of wheat seedlings, both alone and in seedlings infected with F. pseudograminearum. Improved plant growth may be related to the ability of B. subtilis YB-15 to secrete indole acetic acid and siderophores, as well as to solubilize phosphorus. In addition, the genome of strain YB-15 was determined, resulting in a complete assembled circular genome of 4,233,040 bp with GC content of 43.52% consisting of 4207 protein-encoding genes. Sequencing the B. subtilis YB-15 genome further revealed genes for encoding carbohydrate-active enzymes, biosynthesis of various secondary metabolites, nutrient acquisition, phytohormone production, chemotaxis and motility, which could explain the potential of strain YB-15 to be plant growth-promoting bacteria and biological control agent. B. subtilis YB-15 appears to be a promising biocontrol agent against Fusarium crown rot as well as for wheat growth promotion.