Quinolizidine-Based Variations and Antifungal Activity of Eight Lupinus Species Grown under Greenhouse Conditions

Fusarium oxysporum is an aggressive phytopathogen that affects various plant species, resulting in extensive local and global economic losses. Therefore, the search for competent alternatives is a constant pursuit. Quinolizidine alkaloids (QA) are naturally occurring compounds with diverse biological activities. The structural diversity of quinolizidines is mainly contributed by species of the family Fabaceae, particularly the genus Lupinus. This quinolizidine-based chemo diversity can be explored to find antifungals and even mixtures to address concomitant effects on F. oxysporum. Thus, the antifungal activity of quinolizidine-rich extracts (QREs) from the leaves of eight greenhouse-propagated Lupinus species was evaluated to outline promising QA mixtures against F. oxysporum. Thirteen main compounds were identified and quantified using an external standard. Quantitative analysis revealed different contents per quinolizidine depending on the Lupinus plant, ranging from 0.003 to 32.8 mg/g fresh leaves. Bioautography showed that all extracts were active at the maximum concentration (5 µg/µL). They also exhibited >50% mycelium growth inhibition. All QREs were fungistatic except for the fungicidal QRE of L. polyphyllus Lindl. Angustifoline, matrine, 13α-hydroxylupanine, and 17-oxolupanine were ranked to act jointly against the phytopathogen. Our findings constitute reference information to better understand the antifungal activity of naturally afforded QA mixtures from these globally important plants.

The expediency of using a plant protection system using the microbiological fungicide BisolbiSan, W in the cultivation of winter wheat in the Southern natural and agricultural zone of the Rostov region

The authors analyzed the biological effectiveness of the integrated plant protection system formed when the microbiological fungicide BisolbiSan, Zh was included in the classical protection scheme adopted in the farms of the Rostov region. The biological effectiveness of the integrated protection system, including the fungicide BisolbiSan, was analyzed, the impact of the studied protection system on the yield, the quality of the grain obtained, the phytosanitary condition of the crop during the growing season on winter wheat crops of the variety Nakhodka with the use of a plant protection system, including the fungicide BisolbiSan, Zh. The fungicide BisolbiSan, containing a culture of rhizospheric bacteria Bacillus subtilis strain H-13, suppresses the germination of spores and mycelium growth of phytopathogenic fungi due to the multilateral action of bacterial metabolites, without causing the formation of resistance in pathogens. It was found that the protection system used practically does not cause a decrease in grain quality — in terms of the average protein and gluten content, the grain at the experimental site even slightly exceeds the grain obtained from the control site by 16.88% and 27.8%. With the cost of winter wheat grain of 1100 rubles/kg, an increase in the yield in the experiment of 3.8 kg/ha in relation to control and the cost of an experimental protection system in the amount of 3,357 rubles/ha, revenue amounted to 823 rubles/ha.

Superabsorbent Polymer Seed Coating Reduces Leaching of Fungicide but Does Not Alter Their Effectiveness in Suppressing Pathogen Infestation

Superabsorbent polymers (SAPs) applied to soil have been recognized as water reservoirs that allow plants to cope with periods of drought. Their application as a seed coat makes water available directly to the seeds during their germination and early growth phase, but on the other hand, it can affect the efficiency of plant protection substances used in seed dressing. In our experiments, we evaluated the effect of seed coating with SAP on fungicide leaching and changes in their effectiveness in suppressing Fusarium culmorum infestation. Leaching of fungicide from wheat seeds coated with SAP after fungicide dressing, as measured by the inhibition test of mycelium growth under in vitro conditions, was reduced by 14.2–15.8% compared to seeds without SAP coating. Germination of maize seeds and growth of juvenile plants in artificially infected soil did not differ significantly between seeds dressed with fungicide alone and seeds treated with SAP and fungicide. In addition, plants from the seeds coated with SAP alone grew significantly better compared to untreated seeds. Real-time PCR also confirmed this trend by measuring the amount of pathogen DNA in plant tissue. Winter wheat was less tolerant to F. culmorum infection and without fungicide dressing, the seeds were unable to germinate under strong pathogen attack. In the case of milder infection, similar results were observed as in the case of maize seeds.

Pathogenicity of Phytophthora × alni Isolates Obtained from Symptomatic Trees, Soil and Water against Alder

Phytophthora alni complex (P. × alni, P. × multiformis, P. uniformis) are pathogens attacking alder seedlings and trees, causing significant losses in nurseries and natural tree stands. Decay of alder trees has been observed in Poland for over a dozen years. Overall, 25 Polish isolates of P. × alni obtained from symptomatic alder trunks, rhizosphere soil surrounding infected trees, and nearby natural streams were compared with isolates from symptomatic trunks obtained in France, Belgium and Hungary. Morphologic characterization of mycelium, vegetative and generative organs, temperature effect on mycelium growth, and their pathogenicity were studied. The mycelium growth rate of isolates from symptomatic plants was fastest on Carrot Agar (CA) medium, and from soil and water on Vegetable Agar (V8A) medium. The sizes of zoosporangia varied depending on their origin. The isolates that originated from the soil had the largest zoosporangia. The diameter of the oogonia and antheridia did not differ regardless of their origin. The results of pathogenicity tests of P. × alni isolates obtained from different sources showed that the soil isolates were the most aggressive in each test, followed by the isolates from the trunks and water. A simple test of leaf colonization can give an idea of the aggressiveness of the isolate towards the shoots and roots. No morphological or physiological markers of aggressiveness have been found.

Colloidal Silver Hydrogen Peroxide: New Generation Molecule for Management of Phytopathogens

Plant pathogenic fungi and bacteria are a significant threat to global commercial crop production resulting in increased cost of production, reduced crop establishment and productivity. An effort was made to study the antimicrobial activity of silver hydrogen peroxide (SHP) against selected plant pathogenic fungi and bacteria under in vitro conditions. Higher antibacterial activity of SHP was observed against Xanthomonas axonopodis pv. citri (Xac; 39.67 mm), Xanthomonas citri pv. punicae (Xap; 39.00 mm), and Ralstonia solanacearum (Rs; 36.67 mm) at 500 ppm concentration. SHP was superior to streptocycline (500 ppm) against Xac (25.33 mm) and Xcp (22.67 mm) at 100 ppm. The soil-borne fungi viz., Pythium aphanidermatum and Fusarium solani failed to initiate mycelium growth on PDA at the concentration of 5000 ppm and above. The average size of SHP particles was 462 nm in diameter, and 73.40% of particles had the size of 378 nm, which reflects the particles present in SHP solution in the form of colloids. The effective doses (100–5000 ppm) did not show any phytotoxicity symptoms in plants, while leaf necrosis was noticed at 10,000 ppm after four days of application. SHP (≤5000 ppm) can be used to effectively manage both fungal and bacterial plant pathogens by a single application. Further field studies need to be conducted for validation and commercial use of SHP.

Purification, Identification And Characterization of Nag2 N-Acetylglucosaminidase From Trichoderma Virens Strain Mango

Background: N -acetylglucosaminidase (NAGase) could liberate N -acetylglucosamine (GlcNAc) from GlcNAc-containing oligosaccharides. Trichoderma spp. is an important source of chitinase, particularly NAGase for industrial use. nag1 and nag2 genes encoding NAGase , are found in the genome in Trichoderma spp. The deduced Nag1 and Nag2 shares ~55% homology in Trichoderma virens. Most studies were focus on Nag1 and nag1 previously. Results: The native NAGase (TvmNAG2) was purified to homogeneity with molecular mass of ~68 kDa on SDS-PAGE analysis, and identified as Nag2 by MALDI/MS analysis from an isolate T. virens strain mango. RT-PCR analyses revealed that only nag2 gene was expressed in liquid culture of T. virens , while both of nag1 and nag2 were expressed in T. virens cultured on the plates. TvmNAG2 was thermally stable up to 60 o C for 2 h, and the optimal pH and temperature were 5.0 and 60-65 o C, respectively, using p -nitrophenyl- N -acetyl- β -D-glucosaminide ( p NP-NAG) as substrate. Using colloidal chitin as substrate, the end product catalyzed by TvmNAG2 was GlcNAc, based on HPLC and TLC analyses. The optimal temperature for TvmNAG2 to produce GlcNAc was 40 o C. TvmNAG2 possesses antifungal activity, inhibiting the mycelium growth of Sclerotium rolfsii . And it was resistant to the proteolysis by papain and trypsin. Conclusions: The native Nag2, TvmNAG2 was purified and identified from T. virens strain mango, as well as enzymatic properties. To our knowledge, it is the first report with the properties of native Trichoderma Nag2.

The Role of the GSTF11 Gene in Resistance to Powdery Mildew Infection and Cold Stress

Oilseed rape (Brassica napus) is an economically important crop. In a temperate climate, powdery mildew Erysiphe crucifertaum can drastically reduce its yield. Nevertheless, cultivars resistant to this fungal disease have not yet been selected. Glutathione S-transferase GSTF11 is involved in glucosinolate (GSL) biosynthesis and response to stress, including fungal deceases. However, the impact of exogenous GSTF11 gene expression on resistance to powdery mildew has not yet been confirmed and requires further investigation. Transgenic B. napus was generated for this purpose. It demonstrated increased GST activity and a higher GSH:GSSG ratio under normal conditions. Powdery mildew Erysiphe crucifertaum caused 50% mortality in wild type (WT) plants. In most of transgenic plants, mycelium growth was inhibited. The infection contributed to higher GSTF11 expression and increased levels of glutathione (GSH) and oxidized glutathione (GSSG) in both transgenic and WT plants. In contrast, GSTF11 mRNA content, GST activity and GSSG level were lower only in WT plants. In transgenic plants, increased resistance to powdery mildew correlated with a lower GSH:GSSG ratio, indicating a higher content of neutralized toxic molecules. GSTF11 expression was also affected by cold stress, but not drought. At −1 °C, the expression level increased only in transgenic plants. Therefore, GSTF11 appears to be nonspecific and is able to protect plants under several types of stress. This gene could be used as a target in the production of stress tolerant cultivars.

Evaluation of the Potential of Agro-Industrial Waste-Based Composts to Control Botrytis Gray Mold and Soilborne Fungal Diseases in Lettuce

Composts are widely used in horticulture as organic amendments to improve the properties of soils. Composts have also been reported to enhance the disease suppressive potential of soils and, therefore, could be used as a strategy for managing plant diseases. The aim of this study was to test the ability of soils amended with four different agro-industrial waste-based composts (chestnut peels and shells, spent coffee grounds, grape marc, and olive leaves) to inhibit the growth and activity of Botrytis cinerea and several soilborne pathogens. First, the capacity of aqueous compost extracts to inhibit the growth of Botrytis cinerea and five soilborne fungi was evaluated in vitro using a broth macrodilution method. Second, lettuce plants were grown on soils amended with composts and inoculated either with B. cinerea or the soilborne fungus Fusarium oxysporum Schlechtendahl isolated from lamb’s lettuce. The determination of minimal inhibitory concentrations indicated that none of the composts inhibited the mycelium growth of the selected fungal pathogens. However, the pathogens did not cause any damage on plants grown on the chestnut- and olive-based composts. Lettuce yields were also highest for plants grown with composts made from chestnut and olive, irrespective of the amount of compost incorporated into soils (5% or 10%, weight basis). The grape-based compost also exhibited a fertilization effect, although the effect was associated with increased Fusarium wilt severity. Both N immobilization and symbiosis with the compost’s microflora were used to explain the pathogenicity of F. oxysporum Schlechtendahl in response to amendment with composts made from grape and coffee wastes. The beneficial effects of the chestnut- and olive-based composts reported in this study could be exploited in strategies aimed at reducing reliance on synthetic pesticides for the control of fungi in lettuce cultivation.

Effect of common foods as supplements for the mycelium growth of Ganoderma lucidum and Pleurotus ostreatus on solid substrates

The transition from a linear to a circular economy is urgently needed to mitigate environmental impacts and loss of biodiversity. Among the many potential solutions, the development of entirely natural-based materials derived from waste is promising. One such material is mycelium-bound composites obtained from the growth of fungi onto solid lignocellulosic substrates, which find applications such as insulating foams, textiles, packaging, etc. During growth, the fungus degrades and digests the substrate to create a web-like stiff network called mycelium. The development of the mycelium is influenced by several factors, including the substrate composition. As food waste accounts for nearly 44% of total municipal solid waste, incorporating food in the substrate composition could be a means to increase the nutrients absorbed by the fungus. In this paper, we study the effects of the addition of food supplements on the growth of two fungal species, Ganoderma lucidum and Pleurotus ostreatus. The substrates, the food supplements, and the mycelia are characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and optical microscopy. Our results show that addition of barley as a supplement significantly boosts the growth of G. lucidum and P. ostreatus. Using a common food as a nutritious enrichment for the development of mycelium is a simple and straightforward strategy to create waste-based mycelium-bound biocomposites for a large range of applications, on-site, therefore promoting a circular economy.

Cultivation of mycelium of the edible fungus Pleurotus ostreatus (oyster mushroom) with the use of wet sparging grain, the waste of the brewing industry.

Wet sparging grain, a waste product of brewery, was shown to be successfully utilized as a supplement to the nutrient media and substrates for both isolation of the vegetative mycelium of the Pleurotus ostreatus mushroom, as well as for its further recovery and growing the carposomes. We studied the influence of the wet sparging grain on mycelium growth. Cultivation results demonstrated that wet sparging grain is an efficient additional component to the minimal agarized nutrient media for P. ostreatus growth and isolation and to its common fruit body cultivation substrates. Even the depleted agaric media and substrates with addition of the sparging grain allowed intensive growth of the P. ostreatus mycelium and its fructifying. Practical Application: Addition of wet sparging grain to poor cheap substrates increases their quality for rearing the edible oyster mushroom mycelium to the level of reach substrates, and allows utilization of agricultural wastes. The technique is ready for application and patented in the Russian Federation.