Results of in vitro study of thymol, a natural chemosensitizer, as a potential agent for overcoming of difenoconazole resistance of Parastagonospora nodorum causing glume and leaf blotch of wheat are first reported. The level of difenoconazole resistance of a natural mutant PNm1 strain with low sensitivity to the Dividend fungicide (a.i. difenoconazole) was determined by the cultivation of this isolate on potato dextrose agar in the presence of the fungicide at sub-lethal and lethal (in relation to the initial fungicide-sensitive strain) concentrations. A principal possibility of the thymol use to overcome resistance of P. nodorum to DMI (demethylation inhibitors) fungicides is shown. Co-application of this compound with Dividend SC, 3 % resulted in a significant reduction of resistance of the mutant strain and enhancement of its sensitivity to difenoconazole up to the level corresponding to the initial non-resistant isolate.

Chitosan hydrolyzate containing low-molecular-weight chitosan (≤24 kDa) and its oligomers (≤1.2 kDa) has been obtained via chemical depolimerization of high-molecular-weight chitosan by nitric acid. The fractions of the obtained chitosan hydrolyzate have been characterized by high performance gel permeation chromatography and proton magnetic resonance. The test performed on detached leaves of wheat has shown that the hydrolyzate completely inhibits the development of Stagonospora nodorum, a casual agent of the septoria leaf blotch, at a concentration of 200 μg/mL. A similar test with detached tobacco leaves has shown that the hydrolyzate at a concentration of 100 μg/mL also inhibits the development of Alternaria longipes, which causes brown spot of tobacco, by 75%.

В обзоре процесс диссоциации рассматривается как один из важных факторов, создающих гетерогенность популяции бактерий. Частота диссоциативных переходов составляет 10-10 на одно клеточное деление. Подчеркивается, что существуют строгие коррелятивные зависимости между генетическими, физиолого-биохимическими и морфологическими различиями диссоциантов, причем первичные фенотипические изменения происходят в их клеточных оболочках (в размере и химическом строении капсулы, клеточной стенки и цитоплазматической мембраны), что определяет различия в морфологии клеток и колоний, скорости роста, устойчивости к внешнему воздействию, способности к синтезу биологически активных веществ. Даны некоторые практические советы для прогнозирования и управления гетерогенным составом популяции, создаваемым процессом диссоциации, для стабилизации выхода синтезируемых клетками практически ценных веществ.

Garlic (Allium sativum L., family Amaryllidaceae) plants are usually used because of bioactive compounds in their leaves and bulbs. Compounds extracted from this plant are often able to protect against some diseases. There is not enough information about infusions garlic extracts that can be used for plant pathogen control. Creating effective biologicals to protect plants against various diseases is an urgent task to improve crop yields. In this work, the bioactive compounds possessing activity against some phytopathogens were isolated from garlic plant bulbs Allium sativum L. A complex of lectin-allinase and peptide with molecular weight of 4392 Da was obtained from A. sativum bulbs. This complex described in literature before is consisted of allinase enzyme (molecular weight 54 kDa) and mannose-specific garlic lectin (ASA) with molecular weight of 6.4 kDa, and is formed when the bulb tissues are ground. Since, to our knowledge, no data on the biological action of this complex were reported before, we studied its activity against the pathogen of rice blast Magnaporthe grisea. This study showed that the lectin-allinaza complex had no suppressive effect on the pathogen spore germination (spore germination both in control and under treatment was at the 80-90 % level), but reduced the number of necrosis on treated leaves of rice (the percentage of uninfected leaves increased from 15 % in control to 75 %). Thus, the complex did not affect M. grisea directly, but protected plants upon their infection by this pathogenic fungus. These findings suggest that lectinallinaza complex isolated from garlic bulbs is able to induce resistance to M. grisea, probably by activation of plant defense responses. The ability of obtained peptide not described in literature before to inhibit action of B. sorokiniana, the causative agent of Helminthosporium root rot and barley leaf blotch, at concentration corresponding to 10-11 mg protein/ml, was shown on wheat and barley leaves. Since the peptide 4392 Da did not inhibit the growth of B. sorokiniana colonies in vitro, it can be assumed that the peptide is capable of activating the protective functions of the plant during the pathogen infection. When evaluating the effect of the peptide 4392 Da on seed germination and growth stimulation in peas, cucumber, mustard, sunflower and garlic, the germination of garlic seeds increased by 13.6 % (р < 0.01), while 65.5 % (р < 0.01) increase in the length of its stems and a four-fold increase of the root length were observed, but the peptide had no effect on seeds and sprouts of the other crops tested. Thus, the resulting substances do not possess phytotoxicity, and due to its high activity at low concentrations show very low discharge at its application. Moreover, by virtue of its origin they are absolutely harmless for humans and animals and are environmentally safe technology of plant protection, which is especially important in modern agriculture.

Garlic (Allium sativum L., family Amaryllidaceae) plants are usually used because of bioactive compounds in their leaves and bulbs.Compounds extracted from this plant are often able to protect against some diseases.There is not enough information about infusions garlic extracts that can be used for plant pathogen control.Creating effective biologicals to protect plants against various diseases is an urgent task to improve crop yields.In this work, the bioactive compounds possessing activity against some phytopathogens were isolated from garlic plant bulbs Allium sativum L. A complex of lectin-allinase and peptide with molecular weight of 4392 Da was obtained from A. sativum bulbs.This complex described in literature before is consisted of allinase enzyme (molecular weight 54 kDa) and mannose-specific garlic lectin (ASA) with molecular weight of 6.4 kDa, and is formed when the bulb tissues are ground.Since, to our knowledge, no data on the biological action of this complex were reported before, we studied its activity against the pathogen of rice blast Magnaporthe grisea.This study showed that the lectin-allinaza complex had no suppressive effect on the pathogen spore germination (spore germination both in control and under treatment was at the 80-90 % level), but reduced the number of necrosis on treated leaves of rice (the percentage of uninfected leaves increased from 15 % in control to 75 %).Thus, the complex did not affect M. grisea directly, but protected plants upon their infection by this pathogenic fungus.These findings suggest that lectinallinaza complex isolated from garlic bulbs is able to induce resistance to M. grisea, probably by activation of plant defense responses.The ability of obtained peptide not described in literature before to inhibit action of B. sorokiniana, the causative agent of Helminthosporium root rot and barley leaf blotch, at concentration corresponding to 10-11 mg protein/ml, was shown on wheat and barley leaves.Since the peptide 4392 Da did not inhibit the growth of B. sorokiniana colonies in vitro, it can be assumed that the peptide is capable of activating the protective functions of the plant during the pathogen infection.When evaluating the effect of the peptide 4392 Da on seed germination and growth stimulation in peas, cucumber, mustard, sunflower and garlic, the germination of garlic seeds increased by 13.6 % (р < 0.01), while 65.5 % (р < 0.01) increase in the length of its stems and a four-fold increase of the root length were observed, but the peptide had no effect on seeds and sprouts of the other crops tested.Thus, the resulting substances do not possess phytotoxicity, and due to its high activity at low concentrations show very low discharge at its application.Moreover, by virtue of its origin they are absolutely harmless for humans and animals and are environmentally safe technology of plant protection, which is especially important in modern agriculture.

Use of natural compounds against phytopathogenic microorganisms instead of chemicals is regarded as the safer approach to protect environment, consumers and the staff. Previously in the laboratory tests, the Pravastatin, an inhibitor of sterol biosynthesis, was shown to prevent development of helminthosporium root rot, caused by Bipolaris sorokiniana, in spring barley seedlings. Further to this, we studied the protective effect of Pravastatin against B. sorokiniana in test field (Moscow Province). Before sowing, the spring barley (variety Zazerskii 85) seeds, naturally infected with B. sorokiniana, were treated with Pravastatin (0.05, 0.075 e 0.1 % for 24 hours). The pre-sowing examination of untreated naturally infected seeds showed the plant damage by helminthospor ium root rot at 8.9 % and the disease severity at 36.8 %. Small-plot field trials showed that treatments of spring barley seeds with soaking in 0.075 or 0.1 % Pravastatin solutions for 24 hours before their sowing decreased the number of plans damaged by B. sorokiniana, as well as reduced the disease severity. The maximal protective effect was produced by Pravastatin at the concentration of 0.1 %. It Ðen. 3. Aeeia iaacaiiie e iiacaiiie ÷anoe (A) e eonoenoinou (A) o ðanoaiee y÷iaiy (Hordeum vulgare L.) niðoa Cacaðneee 85 â eiioa oacu eouaiey (oaca 29) iinea iðaaiinaâiie iaðaaioee naiyi ðanoâiðii iðaâanoaoeia â ðaciuo eiioaioðaoeyo: a — noaaee; a — eiðie (Iineiâneay iae., 2009 aia).

Use of natural compounds against phytopathogenic microorganisms instead of chemicals is regarded as the safer approach to protect environment, consumers and the staff. Previously in the laboratory tests, the Pravastatin, an inhibitor of sterol biosynthesis, was shown to prevent development of helminthosporium root rot, caused by Bipolaris sorokiniana, in spring barley seedlings. Further to this, we studied the protective effect of Pravastatin against B. sorokiniana in test field (Moscow Province). Before sowing, the spring barley (variety Zazerskii 85) seeds, naturally infected with B. sorokiniana, were treated with Pravastatin (0.05, 0.075 и 0.1 % for 24 hours). The pre-sowing examination of untreated naturally infected seeds showed the plant damage by helminthosporium root rot at 8.9 % and the disease severity at 36.8 %. Small-plot field trials showed that treatments of spring barley seeds with soaking in 0.075 or 0.1 % Pravastatin solutions for 24 hours before their sowing decreased the number of plans damaged by B. sorokiniana, as well as reduced the disease severity. The maximal protective effect was produced by Pravastatin at the concentration of 0.1 %. It was also found that seed treatments with Pravastatin at all tested concentrations did not influence negatively on the seed germinating capacity or density of planting at the tillering stage (phase 29). In addition, seed soaking in a 0.1 % Pravastatin solution resulted in increase of productive stem number at the stage of milky-wax ripeness (phase 83).

Influence of pravastatin, a product of secondary methabolism of actinomycete Streptomyces carbophilus, on Helminthosporium root rot (causal agent Bipolaris sorokiniana) was studied. Preinoculation treatment of spring barley seeds (cv. Zazersky 85) with pravastatin was shown to reduce both the number of diseased seedlings and the disease severity.