Mushroom-Derived Novel Selenium Nanocomposites' Effects on Potato Plant Growth and Tuber Germination.

Multicomponent materials, where nanosized selenium (Se) is dispersed in polymer matrices, present as polymer nanocomposites (NCs), namely, selenium polymer nanocomposites (SeNCs). Selenium as an inorganic nanofiller in NCs has been extensively studied for its biological activity. More ecologically safe and beneficial approaches to obtain Se-based products are the current challenge. Biopolymers have attained great attention with perspective multifunctional and high-performance NCs exhibiting low environmental impact with unique properties, being abundantly available, renewable, and eco-friendly. Composites based on polysaccharides, including beta-glucans from edible and medicinal mushrooms, are bioactive, biocompatible, biodegradable, and have exhibited innovative potential. We synthesized SeNCs on the basis of the extracellular polysaccharides of several medicinal mushrooms. The influence of bio-composites from mushrooms on potato plant growth and tuber germination were studied in two potato cultivars: Lukyanovsky and Lugovskoi. Bio-composites based on Grifola umbellata demonstrated the strongest positive effect on the number of leaves and plant height in both cultivars, without negative effect on biomass of the vegetative part. Treatment of the potato tubers with SeNC from Gr. umbellata also significantly increased germ length. Potato plants exposed to Se-bio-composite from Ganoderma lucidum SIE1303 experienced an increase in the potato vegetative biomass by up to 55% versus the control. We found earlier that this bio-composite was the most efficient against biofilm formation by the potato ring rot causative agent Clavibacter sepedonicus (Cms). Bio-composites based on Pleurotus ostreatus promoted increase in the potato root biomass in the Lugovskoi cultivar by up to 79% versus the control. The phytostimulating ability of mushroom-based Se-containing bio-composites, together with their anti-phytopathogenic activity, testifies in favor of the bifunctional mode of action of these Se-biopreparations. The application of stimulatory green SeNCs for growth enhancement could be used to increase crop yield. Thus, by combining myco-nanotechnology with the intrinsic biological activity of selenium, an unexpectedly efficient tool for possible applications of SeNCs could be identified.

Novel Nanobiocomposites Based on Natural Polysaccharides as Universal Trophic Low-Dose Micronutrients.

New promising manganese-containing nanobiocomposites (NCs) based on natural polysaccharides, arabinogalactan (AG), arabinogalactan sulfate (AGS), and κ-carrageenan (κ-CG) were studied to develop novel multi-purpose trophic low-dose organomineral fertilizers. The general toxicological effects of manganese (Mn) on the vegetation of potatoes (Solanum tuberosum L.) was evaluated in this study. The essential physicochemical properties of this trace element in plant tissues, such as its elemental analysis and its spectroscopic parameters in electron paramagnetic resonance (EPR), were determined. Potato plants grown in an NC-containing medium demonstrated better biometric parameters than in the control medium, and no Mn accumulated in plant tissues. In addition, the synthesized NCs demonstrated a pronounced antibacterial effect against the phytopathogenic bacterium Clavibacter sepedonicus (Cms) and were proved to be safe for natural soil microflora.

Selenium Nanocomposites in Natural Matrices as Potato Recovery Agent.

The paper presents a study of the effect of chemically synthesized selenium nanocomposites (Se NCs) in natural polymer matrices arabinogalactan (AG) and starch (ST) on the viability of the potato ring rot pathogen Clavibacter sepedonicus (Cms), potato plants in vitro, and the soil bacterium Rhodococcus erythropolis. It was found that the studied Se NCs have an antibacterial effect against the phytopathogenic Cms, reducing its growth rate and ability to form biofilms. It was revealed that Se NC based on AG (Se/AG NC) stimulated the growth and development of potato plants in vitro as well as their root formation. At the same time, Se did not accumulate in potato tissues after the treatment of plants with Se NCs. The safety of the Se NCs was also confirmed by the absence of a negative effect on the growth and biofilm formation of the soil bacterium R. erythropolis. The obtained results indicate that Se NCs are promising environmentally safe agents for the protection and recovery of cultivated plants from phytopathogenic bacteria.

Pesticides impact on Clavibacter michiganensis ssp. sepedonicus biofilm formation.

The effect of various pesticides on the biofilm formation by the phytopathogenic bacterium Clavibacter michiganensis ssp. sepedonicus (Cms), the potato ring rot causative agent, was explored for the first time. Systemic herbicides: 2,4-D, diuron, glyphosate, clopyralid, fluorodifen, as well as the commercial preparations "Lazurite," "Ridomil Gold," and the mitochondria inhibiting pesticides analog, sodium monoiodoacetate, were studied. These pesticides' effect on the Cms biofilm formation was shown to be distinct and dependent on the agent under question. Cms biofilm formation was reduced when exposed to sodium monoiodoacetate, as well as "Lazurite" preparation, that could be due to the bactericidal effect of these agents. 2,4-D and "Ridomil Gold" preparation stimulated the biofilm formation. Systemic herbicides diuron, glyphosate, clopyralid, fluorodifen did not exert appreciable influence on the process of bacterial biofilm formation.