Plant Metabolites Affect Fusarium proliferatum Metabolism and In Vitro Fumonisin Biosynthesis.

Fusarium proliferatum is a common hemi-biotrophic pathogen that infect a wide range of host plants, often leading to substantial crop loss and yield reduction. F. proliferatum synthesizes various mycotoxins, and fumonisins B are the most prevalent. They act as virulence factors and specific effectors that elicit host resistance. The effects of selected plant metabolites on the metabolism of the F. proliferatum strain were analyzed in this study. Quercetin-3-glucoside (Q-3-Glc) and kaempferol-3-rutinoside (K-3-Rut) induced the pathogen's growth, while DIMBOA, isorhamnetin-3-O-rutinoside (Iso-3-Rut), ferulic acid (FA), protodioscin, and neochlorogenic acid (NClA) inhibited fungal growth. The expression of seven F. proliferatum genes related to primary metabolism and four FUM genes was measured using RT-qPCR upon plant metabolite addition to liquid cultures. The expression of CPR6 and SSC1 genes was induced 24 h after the addition of chlorogenic acid (ClA), while DIMBOA and protodioscin reduced their expression. The transcription of FUM1 on the third day of the experiment was increased by all metabolites except for Q-3-Glc when compared to the control culture. The expression of FUM6 was induced by protodioscin, K-3-Rut, and ClA, while FA and DIMBOA inhibited its expression. FUM19 was induced by all metabolites except FA. The highest concentration of fumonisin B1 (FB1) in control culture was 6.21 µg/mL. Protodioscin did not affect the FB content, while DIMBOA delayed their synthesis/secretion. Flavonoids and phenolic acids displayed similar effects. The results suggest that sole metabolites can have lower impacts on pathogen metabolism and mycotoxin synthesis than when combined with other compounds present in plant extracts. These synergistic effects require additional studies to reveal the mechanisms behind them.

Metabolomic Aspects of Conservative and Resistance-Related Elements of Response to Fusarium culmorum in the Grass Family.

BACKGROUND: Fusarium head blight (FHB) is a serious fungal disease affecting crop plants, causing substantial yield reductions and the production of mycotoxins in the infected grains. Achieving progress in the breeding of crops with increased resistance and maintaining a high yield is not possible without a thorough examination of the molecular basis of plant immunity responses. METHODS: LC-MS-based metabolomics approaches powered by three-way ANOVA and the selec-tion of differentially accumulated metabolites (DAMs) were used for studying plant immunity. A correlation network and functional enrichment analysis were conducted on grains of barley and wheat genotypes that were resistant or susceptible to FHB, as well as on the model grass Brachypodium distachyon (Bd), as this is still poorly understood at the metabolomic level. RESULTS: We selected common and genotype-specific DAMs in response to F. culmorum inoculation. The immunological reaction at the metabolomic level was strongly diversified between resistant and susceptible genotypes. DAMs that were common to all tested species from the porphyrin, flavonoid, and phenylpropanoid metabolic pathways were highly correlated, reflecting con-servativeness in the FHB response in the Poaceae family. Resistance-related DAMs belonged to different structural classes, including tryptophan-derived metabolites, pyrimidines, the amino acids proline and serine, as well as phenylpropanoids and flavonoids. The physiological re-sponse to F. culmorum of Bd was close to that of barley and wheat genotypes; however, metabo-lomic changes were strongly diversified. CONCLUSIONS: Combined targeted and untargeted metabolomics provides comprehensive knowledge about significant elements of plant immuni-ty that have the potential to be molecular biomarkers of enhanced resistance to FHB in the grass family. Thorough examination of the Bd metabolome in juxtaposition with diversified geno-types of barley and wheat facilitated its use as a model grass for plant-microbe interaction.

Geographical Origin Does Not Modulate Pathogenicity or Response to Climatic Variables of Fusarium oxysporum Associated with Vascular Wilt on Asparagus.

Asparagus crop is distributed worldwide, covering very different climatic regions. Among the different diseases that affect asparagus, vascular Fusarium wilt, caused by Fusarium oxysporum f. sp. aparagi (Foa), stands out. It is not only the cause of large economic losses due to a decrease in yield and shortened longevity of the plantation, but also prevents replanting. This work aimed to determine if F. oxysporum isolates associated with vascular wilt on asparagus have adapted differentially to the different agro-environmental conditions. The potential correlation between origin and mycelial growth under different temperatures and humidity conditions was analysed for isolates from asparagus fields cultivated in northern and southern Europe. The genetic and pathogenic variability were also analysed. While a clear effect of water activity on mycelial growth was observed, all isolates responded in a similar way to changes in water activity in the medium, regardless of their geographical origin. The results revealed a low genetic variability of F. oxysporum isolates associated with vascular wilt on asparagus without signs of differentiation correlated to geographical origin. The southernmost isolates of the two cultivated varieties inoculated did not express more pathogenicity than those isolated from the colder region.

Biochar addition reinforces microbial interspecies cooperation in methanation of sugar beet waste (pulp).

Biogas production and microbial community structure were analyzed as an effect of biochar addition to a fermentation sludge containing sugar beet pulp. Positive effects of the treatment including an increase in process efficiency and better biogas quality were noted. The effect of biochar on AD (anaerobic digestion process) microbial communities was investigated after total DNA extraction from biochar-amended fermentation mixtures by PCR amplification of bacterial 16S rRNA gene fragments and Illumina amplicon sequencing. A combination of microbiological and physico-chemical analyses was used to study the mechanism by which biochar influences the process of anaerobic digestion of sugar beep pulp. It was found that the main reason of the changes in biogas production was the reshaping of the microbial communities, in particular enrichment of Bacteroidales and Clostridiales. It was proposed that biochar, in addition to being a conductor for mediating interspecies electron transfer, serves also as a habitat for hydrolytic bacteria. It was elucidated that the main driving force for the preferential colonization of biochar surfaces is its hydrophobicity. The presented research indicates the high potential of biochar to stimulate the methane fermentation process.

The Impacts of Asparagus Extract Fractions on Growth and Fumonisins Biosynthesis in Fusarium Proliferatum.

Asparagus is a genus consisting of over two hundred species of perennial plants. Fusariumproliferatum is a major asparagus pathogen and it biosynthesizes a variety of mycotoxins, of which fumonisins B are prevalent. Our previous studies on F.proliferatum strains indicated that asparagus extract affects the expression of FUM1 gene, encoding polyketide synthase, a key enzyme of the FUM gene cluster governing the biosynthesis of fumonisins. An asparagus-derived F.proliferatum strain increased fumonisin B1 production after extract fractions' addition, reaching the maximum 2 or 24 h after treatment. The cultures yielded between 40 and 520 mg of dry weight of mycelia after 14 days of cultivation. The differences in fungal biomass amounts between the whole extract and its fractions may result from synergistic effect of all bioactive compounds present in asparagus extract. Among extract fractions, the methanolic fraction had the highest effect on the dry weight of the mycelium reaching about a 13-fold increase compared to the control. Furthermore, we measured the relative expression of the FUM1 gene. Due to the possible antifungal activity of tested extract fractions, future research will be focused on the identification of the Asparagus officinalis L. compounds responsible for this activity.

Effect of nitrogen fertilization on the production of biogas from sweet sorghum and maize biomass.

The aim of the study was to determine the biogas productivity from selected cultivars of sorghum (Sorghum bicolor Moench) and maize (Zea mays L.) depending on the dose of mineral fertilization with nitrogen. The topic is novelty in the northern Poland area due to the fact that this crop is not very widespread here. The silage samples were derived from two experiments: (1) two factors experiment with sorghum varieties (Arbatax, KWS Maja, Herkules) and two doses of mineral nitrogen fertilization (0 and 150 kg ha-1 N) in split-plot design. (2) one-factor experiment with fodder maize, variety NK Magitop, and two doses of mineral nitrogen fertilization (0 and 150 kg ha-1 N) in a randomized complete block design. The experiment was performed in four replications in the split-plot design. Methane fermentation was carried out under mesophilic conditions. The temperature of the process was 37°C ± 1°C, while pH 7 ± 0.1. The content of total solids in the bioreactor was 7.0%. The composition of the gas produced was measured once a day with the use of an automatic biogas analyser (GFM 416, GasData). The trial was run in triplicate until the daily yield was less than 1% of the cumulative biogas yield [DIN 38 414-S8. Sediments and sediments. Determination of fermentation characteristics; 1985]. Sorghum was characterized by higher average biogas productivity (about 12%), higher methane content in biogas (about 10%), and higher methane productivity (about 43%). It can, therefore, be stated that sorghum represents as an alternative plant to maize for the purpose of biogas production.

Fusarium-Produced Mycotoxins in Plant-Pathogen Interactions.

Pathogens belonging to the Fusarium genus are causal agents of the most significant crop diseases worldwide. Virtually all Fusarium species synthesize toxic secondary metabolites, known as mycotoxins; however, the roles of mycotoxins are not yet fully understood. To understand how a fungal partner alters its lifestyle to assimilate with the plant host remains a challenge. The review presented the mechanisms of mycotoxin biosynthesis in the Fusarium genus under various environmental conditions, such as pH, temperature, moisture content, and nitrogen source. It also concentrated on plant metabolic pathways and cytogenetic changes that are influenced as a consequence of mycotoxin confrontations. Moreover, we looked through special secondary metabolite production and mycotoxins specific for some significant fungal pathogens-plant host models. Plant strategies of avoiding the Fusarium mycotoxins were also discussed. Finally, we outlined the studies on the potential of plant secondary metabolites in defense reaction to Fusarium infection.

Flammulina velutipes treatment of non-sterile tall wheat grass for enhancing biodegradability and methane production.

In this study fungal pretreatment of non-sterile tall wheat grass via the white rot fungi Flammulina velutipes was studied and the effect on biodegradability of lignocellulosic biomass and methane production, was evaluated. Degradation of lignin, cellulose, hemicellulose, and dry matter in non-sterile tall wheat grass during 28 days of fungal pretreatment using different inoculum ratio (0%-50%) and moisture content (MC) (45% MC, 65% MC, and 75% MC) were assessed via comparison to untreated biomass. Pretreatment with F. velutipes was most effective at 65% MC and 40% inoculum ratio, resulting in 22% lignin removal. The corresponding methane yields were 181.3 Ndm3·kg VS-1, which were 280% higher than for the untreated tall wheat grass.