Can the concentration of elements in wild-growing mushrooms be deduced from the taxonomic rank?

The mineral composition of wild-growing mushroom species is influenced by various environmental factors, particularly the chemical properties of the soil/substrate. We hypothesised that element uptake might also correlate with taxonomic classification, potentially allowing us to predict contamination levels based on mushrooms within the same taxonomic rank. This study compared the mineral composition (Ag, As, Ba, Ca, Cd, Co, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, Se, and Zn) of 16 saprotrophic mushroom species from 11 genera across 4 families and 2 orders. Among these were 13 edible and 3 inedible mushrooms, all collected from natural, wild stands in a forest in central-western Poland between 2017 and 2020. Phallus impudicus exhibited the highest mean content of Ba (together with Phallus hadriani) (6.63 and 8.61 mg kg-1, respectively), Ca (with Paralepista gilva and Stropharia rugosoannulata) (803, 735 and 768 mg kg-1, respectively), Cd (with Lycoperdon perlatum) (3.59 and 3.12 mg kg-1, respectively), Co (0.635 mg kg-1), and Fe (with P. hadriani and S. rugosoannulata) (476, 427 and 477 mg kg-1, respectively), while Macrolepiota mastoidea showed the highest content of Ag (1.96 mg kg-1), As (with Coprinus comatus) (1.56 and 1.62 mg kg-1, respectively) and Cu (with Macrolepiota procera and Chlorophyllum rhacodes) (192, 175 and 180 mg kg-1, respectively). Comparing the content of the analysed elements in the genera represented by at least two species, a similarity was observed, the same as the mean concentration in soil under these species. Soil characteristics could be a superior factor that overshadows the impact of the mushroom genus on the elements accumulation, obscuring its role as a determinant in this process. The results are not definitive evidence that belonging to a particular taxonomic rank is a prerequisite condition affecting the accumulation of all elements. A closer focus on this issue is needed.

The Role of Saccharides in the Mechanisms of Pathogenicity of Fusarium oxysporum f. sp. lupini in Yellow Lupine (Lupinus luteus L.).

The primary aim of this study was to determine the relationship between soluble sugar levels (sucrose, glucose, or fructose) in yellow lupine embryo axes and the pathogenicity of the hemibiotrophic fungus Fusarium oxysporum f. sp. Schlecht lupini. The first step of this study was to determine the effect of exogenous saccharides on the growth and sporulation of F. oxysporum. The second one focused on estimating the levels of ergosterol as a fungal growth indicator in infected embryo axes cultured in vitro on sugar containing-medium or without it. The third aim of this study was to record the levels of the mycotoxin moniliformin as the most characteristic secondary metabolite of F. oxysporum in the infected embryo axes with the high sugar medium and without it. Additionally, morphometric measurements, i.e., the length and fresh weight of embryo axes, were done. The levels of ergosterol were the highest in infected embryo axes with a sugar deficit. At the same time, significant accumulation of the mycotoxin moniliformin was recorded in those tissues. Furthermore, it was found that the presence of sugars in water agar medium inhibited the sporulation of the pathogenic fungus F. oxysporum in relation to the control (sporulation of the pathogen on medium without sugar), the strongest inhibiting effect was observed in the case of glucose. Infection caused by F. oxysporum significantly limited the growth of embryo axes, but this effect was more visible on infected axes cultured under sugar deficiency than on the ones cultured with soluble sugars. The obtained results thus showed that high sugar levels may lead to reduced production of mycotoxins by F. oxysporum, limiting infection development and fusariosis.

Anthropogenic contamination leads to changes in mineral composition of soil- and tree-growing mushroom species: A case study of urban vs. rural environments and dietary implications.

Because wild-growing edible mushroom species are frequently consumed, a knowledge of their mineral composition is essential. The content of elements in mushrooms and their possible beneficial or harmful effect may be influenced by the human-impacted environment. Thus, the aim of the study was to analyse the mineral composition of the soil, trees, and especially soil- and tree-growing mushroom species collected from within a city and from rural areas. Due to potentially higher pollution in urban areas, we assumed that mushrooms from a city environment will contain higher levels of mineral elements than those from rural areas and that the high content will be attributed to greater contamination of city soils. Significantly higher concentrations of several elements in soils (Ca, Ba, Bi, Hg, Pb, Sb, Sr, W and Zr) and trees (Ag, Bi, Ce, Co, Mn, Mo, Nd, Pr, Ta, Tm and W) were observed from the samples collected in the city. Additionally, significantly higher contents of Ag, Fe, Hg, Mn, Mo, Sr, Y and Zn in soil-growing, and Al, As, Ba, Cr, Fe, Hg, Ni, Pb, Sr, Ta and Zn in tree-growing mushroom species were recorded from the urban area. These differences formed the basis for the observation that the content of elements in urban mushrooms is generally higher than in those from rural areas. However, a higher content of several soil elements does not necessarily mean that there will be a significantly higher content in fruit bodies. There was also no real risk of consuming soil-growing mushroom species collected in recent years from the city, suggesting that this practice may still be continued.

Free Radicals, Salicylic Acid and Mycotoxins in Asparagus After Inoculation with Fusarium proliferatum and F. oxysporum.

Electron paramagnetic resonance was used to monitor free radicals and paramagnetic species like Fe, Mn, Cu generation, stability and status in Asparagus officinalis infected by common pathogens Fusarium proliferatum and F. oxysporum. Occurrence of F. proliferatum and F. oxysporum, level of free radicals and other paramagnetic species, as well as salicylic acid and mycotoxins content in roots and stems of seedlings were estimated on the second and fourth week after inoculation. In the first term free and total salicylic acid contents were related to free radicals level in stem (P = 0.010 and P = 0.033, respectively). Concentration of Fe(3+) ions in porphyrin complexes (g = 2.3, g = 2.9) was related to the species of pathogen. There was no significant difference between Mn(2+) concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum.

Phytoextraction of potentially toxic elements by six tree species growing on hazardous mining sludge.

The aim of the study was to compare the phytoextraction abilities of six tree species (Acer platanoides L., Acer pseudoplatanus L., Betula pendula Roth, Quercus robur L., Tilia cordata Miller, Ulmus laevis Pall.), cultivated on mining sludge contaminated with arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), thallium (Tl), and zinc (Zn). All six tree species were able to survive on such an unpromising substrate. However, A. platanoides and T. cordata seedlings grown on the polluted substrate showed significantly lower biomass than control plants (55.5 and 45.6%, respectively). As, Cd, Cu, Pb, and Tl predominantly accumulated in the roots of all the analyzed tree species with the following highest contents: 1616, 268, 2432, 547, and 856 mg kg-1, respectively. Zn was predominantly localized in shoots with the highest content of 5801 and 5732 mg kg-1 for U. laevis and A. platanoides, respectively. A. platanoides was the most effective in Zn phytoextaction, with a bioconcentration factor (BCF) of 8.99 and a translocation factor (TF) of 1.5. Furthermore, with the exception of A. pseudoplatanus, the analyzed tree species showed a BCF > 1 for Tl, with the highest value for A. platanoides (1.41). However, the TF for this metal was lower than 1 in all the analyzed tree species. A. platanoides showed the highest BCF and a low TF and could, therefore, be a promising species for Tl phytostabilization. In the case of the other analyzed tree species, their potential for effective phytoextraction was markedly lower. Further studies on the use of A. platanoides in phytoremediation would be worth conducting.

Fusariotoxins in asparagus - their biosynthesis and migration.

Asparagus is often infected by fungi of the Fusarium genus, a causal agent of crown and root rot, which decreases the quantity and quality of spears. Fusarium oxysporum and Fusarium proliferatum are the most severe asparagus pathogens, well known as mycotoxin producers, mainly fumonisins and moniliformin. The present study was undertaken to estimate fumonisin B1, moniliformin and ergosterol concentrations in asparagus tissue. Moreover, the possibility of toxin transport to the edible asparagus part during the inoculation by F. oxysporum and F. proliferatum of different plant parts (root, crown and stem base) and the potential risk for consumers were assessed. Our studies showed that the highest capability of producing fumonisin B1 and moniliformin was demonstrated from isolates of F. proliferatum. The highest level of fumonisin B1 in edible spears was detected when the asparagus crown was inoculated with F. oxysporum and F. proliferatum. The lowest concentration was found in the case of storage root inoculation, which corresponds with mycelium absence and the long distance from the roots to the stem. Similar results were demonstrated for moniliformin. The mycotoxin content was confirmed even in healthy spears (without disease symptoms and mycelium presence), which might indicate that the transport of mycotoxins is possible from the soil through the root system to the top part of the plants.

Genetic variation of Fusarium oxysporum isolates forming fumonisin B(1) and moniliformin.

Thirty single-spore isolates of a toxigenic fungus, Fusarium oxysporum, were isolated from asparagus spears and identified by species-specific polymerase chain reaction (PCR) and translation elongation factor 1-α (TEF) sequence analysis. In the examined sets of F. oxysporum isolates, the DNA sequences of mating type genes (MAT) were identified. The distribution of MAT idiomorph may suggest that MAT1-2 is a predominant mating type in the F. oxysporum population. F. oxysporum is mainly recognised as a producer of moniliformin-the highly toxic secondary metabolite. Moniliformin content was determined by high-performance liquid chromatography (HPLC) analysis in the range 0.05-1,007.47 µg g(-1) (mean 115.93 µg g(-1)) but, also, fumonisin B(1) was detected, in the concentration range 0.01-0.91 µg g(-1) (mean 0.19 µg g(-1)). There was no association between mating types and the mycotoxins biosynthesis level. Additionally, a significant intra-species genetic diversity was revealed and molecular markers associated with toxins biosynthesis were identified.