Growth-Stimulating Activity of Natural Polymer-Based Nanocomposites of Selenium during the Germination of Cultivated Plant Seeds.

The growth-stimulating activity of three selenium nanocomposites (NCs) in various matrices based on arabinogalactan (NC Se/AG, 6.4% Se), starch (NC Se/St, 2% Se), and carrageenan (NC Se/Car, 12% Se) with respect to plants of radish, soybean, and potato was investigated. It was shown that the treatment of plant seeds with NCs stimulated root growth during germination. It was found that the studied NCs affected both the level of lipid peroxidation and the activity of the antioxidant enzyme glutathione peroxidase (GPX). The treatment of radish seeds with NCs stimulated root growth during their germination and reduced the content of diene conjugates (DC) in root tissues. It was shown that soaking seeds in NC Se/AG solution increased the GPX activity in the tissues of the radish root by 40%. Stimulation of soybean root growth under the influence of NC Se/Car may also be associated with the activation of GPX. Furthermore, in potato plants, this NC led to the stimulation of germination; however, this was probably due to the activation of other antioxidant enzymes. The results obtained allow us to consider Se NCs as potential plant growth stimulants.

Selenium Nanocomposites Having Polysaccharid Matrices Stimulate Growth of Potato Plants in Vitro Infected with Ring Rot Pathogen.

The influence of nanocomposites (NC) of selenium in matrices of arabinogalactan (Se/AG) and starch (Se/St) on in vitro vegetation of potato plants, peroxidase activity, and reactive oxygen species has been thoroughly studied. It has been shown that these nanocomposites of selenium have antimicrobial effect to the phytopathogenic bacterium Clavibacter michiganensis ssp. sepedonicus (Cms). In the present investigation, it has been shown that Se/AG NC (6.4% of Se) and Se/St NC (12.0% of Se) have no negative impact on the potato plants healthy and Cms infected, while stimulating their growth, number of leaves and weight of the vegetative part. Se/AG NC has shown a positive effect on potato plants by increasing its immune status by increasing the ROS content and increasing the peroxidase activity. With the use of the element analysis technique, it has been shown that scrutinized nanocomposites are not accumulated in potato plants after the bactericidal processing with the nanocomposites. Se/AG NC and Se/St NC as potential agents used for treatment of potato plants against pathogenic bacteria.

Effect of Selenium-containing Biocomposites from Medicinal Mushrooms on the Potato Ring Rot Causative Agent.

The impact of selenium biocomposites obtained from the medicinal macrobasidiomycetes Ganoderma lucidum, Grifola umbellata, Laetiporus sulphureus, Lentinula edodes, and Pleurotus ostreatus on the viability and biofilm formation capability of the phytopathogenic Gram-positive bacterium Clavibacter michiganensis ssp. sepedonicus (Spieck. et Kotth.) (Cms) was studied. Impairment of bacterial cell viability resulting from their incubation with biocomposites was shown. The decisive role of the composites' selenium component on the biological activity under question was established. The dependence of antimicrobial effect of the selenium-containing specimen on the mushroom systematic position was revealed. The maximal activity was found for the biocomposites based on the extracellular metabolites of L. edodes and G. lucidum. When the biopolymer specimen of fungal origin was added to bacterial suspension, the Cms capability of forming biofilms was found to be distinctly dependent of the biocomposite type, and it was substantially reduced in a number of cases.

Silver-Containing Humic Substance-Based Nanocomposites-Agents for Healing of Potatoes from the Ring Rot.

The influence of silver-containing humic substance (HS)-based nanocomposites (NCs) obtained from mud, shale, and coals of three kinds of deposits in Mongolia on the viability and ability to biofilm formation of a phytopathogenic gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus (Cms), as well as peroxidase activity and potato plant growth in vitro, has been investigated. The maximum reduction of the viability of bacterial cells was found in the case of incubation with HS-mu/Ag NC and HS-coal/Ag NC. It was found that HSs, including HS-mu and HS-sl, and NCs synthesized on the base of these HSs, HS-mud/Ag NC and HS-sl/Ag NC reduce more than twofold the activity of peroxidase in potato tissues. It was also found that HS-co and HS-coal/Ag NC stimulate the potato peroxidase activity, as well as biofilm formation of Cms bacterium. No negative effect of the studied NCs on the growth of potato has been revealed. Moreover, NC HS-mud/Ag based on mud had a stimulating effect on leaf formation in plants.

[Effect of Selenium-Containing Biocomposites Based on Ganoderma Mushroom Isolates Grown in the Presence of Oxopropyl-4-Hydroxycoumarins, on Bacterial Phytopathogens].

Effect of selenium-containing biocomposites obtained from submerged cultures of macrobasidiomycetes Ganoderma applantum, G. cattienensis, G. colossus G. lucidum, G. neojaponicum, and G. valesiacum, on plant pathogenic bacteria Clavibacter michiganensis ssp. sepedonicus (Cms), Micrococcus luteus, Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum, Pseudomonas fluorescens, Pseudomonas viridiflava, and Xanthomonas campestris was studied. Oxopropyl-4-hydroxychromenones were used as components of the fungal nutrient media. The bacteriostatic and bactericidal activity of the Se-containing and Sefree substances of fungal origin against plant pathogenic bacteria was determined using colony-forming units count, the agar well diffusion method, and by turbidity measurements of bacterial suspensions. The composites produced from the extracellular metabolites of G. cattienensis SIE1302 with 4-hydroxy-3-(3-oxo-1,3- diphenyl propyl)-chromen-2-one (S(45)), and of G. lucidum SIE1303 with 4-hydroxy-3-(3-oxo-1-(3-nitrophenyl)- 3-phenylpropyl)-chromen-2-one (S(NO2)) possessed the most pronounced antibacterial action against Cms. The composites produced from the isolates of G. valesiacum 120702 with S(NO2) showed the maximal antibacterial activity against Xanthomonas campestris B-610. High antimicrobial effect of G. lucidum 1315 with S(NO2) against Xanthomonas campestris B-610 and of G. colossus SIE1301 against Pseudomonas fluorescens EL-2.1 was revealed. The pioneering information on the biological activity of coumarin series compounds in their application for producing the substances of fungal origin was obtained.