Biotransformation of copper oxide nanoparticles by the pathogenic fungus Botrytis cinerea

The effects of copper (Cu) on microorganisms have been studied for decades due to its strong antimicrobial activity. Nowadays, emerging technologies are developing new antimicrobial compounds such as CuO and Cu nanoparticles (NPs), or products with their inclusions. In this study two plant pathogenic fungi, Alternaria alternata and Botrytis cinerea, were exposed to Cu in either ionic (Cu2+) or microparticle (MP, CuO) or nanoparticle (NP, Cu or CuO) form, in solid and liquid culturing media. B. cinerea proved to be resistant to CuO and Cu NPs and CuO MPs in comparison to A. alternata as shown by pronounced growth and lower levels of lipid peroxidation. B. cinerea grown in the presence of CuO and Cu NPs and CuO MPs on solid medium formed a blue compound at the fungal/ culturing medium interface, followed by a Cu depletion zone. The blue compound was characterized as Cu-oxalate by Cu-K EXAFS. In B. cinerea, pronounced activity of catechol-type siderophores and/or organic acid secretion apparently induces leaching and mobilization of Cu ions from the CuO MPs, CuO and Cu NPs and their further complexation with extracellularly secreted oxalic acid. As such, the pathogenic fungus B. cinerea may be used for copper extraction and/or purification and synthesis of different materials

Can we discover truffle’s true identity?

This study used elemental and stable isotope composition to characterize Slovenian truffles and used multi-variate statistical analysis to classify truffles according to species and geographical origin. Despite the fact that the Slovenian truffles shared some similar characteristics with the samples originating from other countries, differences in the element concentrations suggest that respective truffle species may respond selectively to nutrients from a certain soil type under environmental and soil conditions. Cross-validation resulted in a 77% correct classification rate for determining the geographical origin and a 74% correct classification rate to discriminate between species. The critical parameters for geographical origin discriminations were Sr, Ba, V, Pb, Ni, Cr, Ba/Ca and Sr/Ca ratios, while from stable isotopes δ18O and δ13C values are the most important. The key variables that distinguish T. magnatum from other species are the levels of V and Zn and δ15N values. Tuber aestivum can be separated based on the levels of Ni, Cr, Mn, Mg, As, and Cu. This preliminary study indicates the possibility to differentiate truffles according to their variety and geographical origin and suggests widening the scope to include stable strontium isotope

Magnesium and calcium overaccumulate in the leaves of a schengen3 mutant of Brassica rapa

Magnesium (Mg) and calcium (Ca) are essential mineral nutrients poorly supplied in many human food systems. In grazing livestock, Mg and Ca deficiencies are costly welfare issues. Here, we report a Brassica rapa loss-of-function schengen3 (sgn3) mutant, braA.sgn3.a-1, which accumulates twice as much Mg and a third more Ca in its leaves. We mapped braA.sgn3.a to a single recessive locus using a forward ionomic screen of chemically mutagenized lines with subsequent backcrossing and linked-read sequencing of second back-crossed, second filial generation (BC2F2) segregants. Confocal imaging revealed a disrupted root endodermal diffusion barrier, consistent with SGN3 encoding a receptor-like kinase required for normal formation of Casparian strips, as reported in thale cress (Arabidopsis thaliana). Analysis of the spatial distribution of elements showed elevated extracellular Mg concentrations in leaves of braA.sgn3.a-1, hypothesized to result from preferential export of excessive Mg from cells to ensure suitable cellular concentrations. This work confirms a conserved role of SGN3 in controlling nutrient homeostasis in B. rapa, and reveals mechanisms by which plants are able to deal with perturbed shoot element concentrations resulting from a “leaky” root endodermal barrier. Characterization of variation in leaf Mg and Ca accumulation across a mutagenized population of B. rapa shows promise for using such populations in breeding programs to increase edible concentrations of essential human and animal nutrients

Operando (micro) XAFS analysis

In the talk the principles of XAS methods were presented with practical examples which illustrate the possibilities and advanced approaches for their use in structural analysis of different types of materials. The emphasis will be on to the use of XAS spectroscopy in operando mode and in combination with X-ray microscopy

Development of cold plasma technologies for surface decontamination of seed fungal pathogens

In view of the ever-growing human population and global environmental crisis, new technologies are emerging in all fields of our life. In the last two decades, the development of cold plasma (CP) technology has offered a promising and environmentally friendly solution for addressing global food security problems. Besides many positive effects, such as promoting seed germination, plant growth, and development, CP can also serve as a surface sterilizing agent. It can be considered a method for decontamination of microorganisms on the seed surface alternative to the traditional use of fungicides. This review covers basics of CP technology and its application in seed decontamination. As this is a relatively young field of research, the data are scarce and hard to compare due to various plasma setups and parameters. On the other hand, the rapidly growing research field offers opportunities for novel findings and applications

Elemental composition of wheat, common buckwheat, and tartary buckwheat grains under conventional production

The elemental composition of cereal and pseudocereal grain is believed to significantly affect the portions of the minerals supplied for particular human populations. Therefore, care needs to be taken to improve the availability of the essential elements and to decrease unwanted metal accumulation in edible plant parts. In the present study, we have investigated the element accumulation in the grain of wheat (Triticum aestivum L.), common buckwheat (Fagopyrum esculentum Moench), and tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.), harvested from the same field under conventional grain production. Soil and grain element compositions were analysed using energy dispersive X-ray fluorescence spectrometry and total reflection X-ray fluorescence spectrometry. The wheat grain shows significantly higher (p<0.05) higher element concentrations than both of the buckwheat species tested. The contents of elements in 100 g grain were higher than the concentrations listed in the literature for wheat and buckwheat flours, which indicates significant losses of elements during milling and polishing. Concerns are raised due to the high and unwanted metal accumulation in wheat and buckwheat. The data indicate that both of these buckwheat species accumulate less metal contaminants when compared to wheat