RU2800426C1 - Bacillus amyloliquefaciens strain as an agent for combating potato rhizoctoniosis - Google Patents

Abstract

FIELD: biotechnology; agriculture.

SUBSTANCE: bacterial strain Bacillus amyloliquefaciens, which has the ability to suppress the development of rhizoctoniosis on potatoes due to the production of fungicidal substances in the nutrient medium during the cultivation of bacteria, was deposited at the All-Russian Research Institute of Agriculture under the registration number RCAM 05515.

EFFECT: extension of the range of agents for combating potato rhizoctoniosis.

1 cl, 5 tbl, 2 ex

Description

The invention relates to biotechnology and agriculture and represents the use of a new strainBacillus amyloliquefaciens P20 as an agent for the control of rhizoctoniosis on potatoes.

Known patent No. 2527291 for the invention "Fungicidal agent for the treatment of potato tubers" with a priority of 05/14/2013, registered at Schelkovo Agrokhim CJSC, IPC A01N 59/00, published on 08/27/2014.

The invention relates to agriculture and can be used when laying potato tubers for storage, as well as when processing them before planting to combat phytopathogens that cause various diseases. A fungicidal agent for treating potato tubers during storage and before planting contains benzoic acid or its amine salts (monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine and N,N-diethylethanolamine) as an active ingredient at a consumption rate of 0.030-0.6 kg a.m./t. The present invention is an effective and affordable means for treating potato tubers during storage and dressing during planting in the absence of a phytocidal effect.

Known patent No. 2761117 for the invention "Technology for the production of a liquid form of a combined biological product based on Bacillus subtilis and Bacillus megaterium var. phosphaticum" with priority dated 09.12.2020, registered at ECOS LLC, IPC A01N 63/22, C12N 1/20, C12R 1/11, C12R 1/125, published on 06.12.2021.

A technology for the production of a liquid combined biological product based on strains of bacteria of the genus Bacillus is described, including separate, one-time cultivation of bacterial strains Bacillus subtilis VKPM B-13494 and Bacillus megaterium var. Phosphaticum. strain VKPM V-13497 with continuous aeration and stirring at a stirrer speed of 250-300 rpm in a liquid nutrient medium containing mannitol, enzymatic peptone, magnesium sulfate, potassium phosphate monosubstituted, sodium chloride and water in specified quantities and mixed in a ratio of 60:40 to 40:60. At the same time, the seeding of the medium is carried out with a mother culture in the exponential growth phase with a concentration of (2-3)⋅10 ⁹ CFU/ml and cultivation is carried out until a stable level of cell titer in the bacterial suspension is established (2-3)⋅10 ⁹ CFU/ml. Then half of the contents are drained from each fermenter and disposed of, after that the volume of liquid in the fermenters is brought to the initial level with a concentrated nutrient medium, mannitol, enzymatic peptone, magnesium sulfate, monosubstituted potassium phosphate, sodium chloride and water with an increased concentration. First cultivated until the titer is (5-10)⋅10 ⁹ CFU/ml. Then half of the contents of each fermenter is poured into the storage tank, and the remaining contents of the fermenters are brought to the original volume with a concentrated nutrient medium, and the cultivation cycle is repeated. At the end of the cultivation cycle, the resulting contents of the storage tank and fermenters are mixed with each other and poured into containers as a finished product for intended use. The shelf life of the drug is increased to 2 years, its adhesion to the treated surfaces and the uniformity of the treatment of the leaf surface of plants are improved.

Known patent No. 2538157 for the invention "The bacterial strain of Bacillus subtilis B 93 VIZR for protecting potatoes from diseases during storage" with priority dated November 27, 2013, registered at the State Scientific Institution All-Russian Research Institute of Plant Protection of the Russian Academy of Agricultural Sciences, IPC C12N 1/20, A01N 63 /00, C12R 1/125, published 01/10/2015

The strain of Bacillus subtilis - I5-12/23, deposited in the State Collection of Microorganisms of the State Scientific Institution VIZR under the registration number Bacillus subtilis 93 VIZR, has antagonistic activity against phytopathogenic fungi and bacteria. The strain can be used to protect potatoes from diseases during storage. EFFECT: invention allows to increase the safety of tubers.

Known patent No. 2704859 for the invention "A strain of the fungus Beauveria bas-siana, used to produce a biological product against the Colorado potato beetle, fungal pathogens and stimulate the growth of potatoes during the growing season, a biological product based on it and a method for stimulating the growth of potatoes during the growing season, protecting it from the Colorado potato beetle and rhizoctoniosis” with priority dated July 16, 2019, registered on Lelyak A.I., IPC A01N 63/00, C12N 1/14, published on October 31, 2019.

The invention is a strain of the entomopathogenic fungus Beauveria bassiana IC 1530-25-1, a method for pre-planting treatment of potato tubers with a biological product and a biological product. When preplanting treatment of potato tubers, a 1-3% aqueous solution of spore-mycelial biomass of the strain of the entomopathogenic fungus Beauveria bassiana IC 1530-25-1 and nutrient medium components with a titer of at least 10 ⁵ CFU/ml are used as a liquid form of a biological preparation. Processing of potato tubers with the specified aqueous solution of the biological product is carried out once with the consumption of the aqueous solution of the biological product 10 liters per 1 ton of potatoes. When spraying potatoes during the growing season with an aqueous solution of a biological product, it is used as a spore-mycelial biomass of the strain of the entomopathogenic fungus Beauveria bassiana IC 1530-25-1 and components of the nutrient medium with a titer of at least 10 ⁶ CFU / ml and a consumption of an aqueous solution of a biological product of 300 l per 1 ha potato planting area. EFFECT: invention makes it possible to protect potatoes from the Colorado potato beetle, a fungal pathogen Thanatephorus cucumeris (an imperfect stage of the fungus - Rhizoctonia solani), which causes rhizoctonia or black scab of potatoes, and also stimulates the growth of potatoes during the growing season.

Known patent No. 2428008 for the invention "Method of combating black leg, rhizoctoniosis, wrinkled and common mosaic of potatoes" with priority dated 01/27/2010, registered at the State Scientific Institution Yakut Scientific Research Institute of Agricultural Academy of the Russian Agricultural Academy, IPC A01N 63/00, published 09/10/2011 G.

The method includes pre-sowing treatment of potato tubers with a microbial preparation, which is a suspension of an equal combination of bacterial strains of Bacillus subtilis TNP-3 and Bacillus subtilis TNP-5 with a content of 1×10 ⁹ COE/ml in tap water (pH 7.8) for 30 minutes at the rate of 300 ml/kg tubers. The invention allows to increase the yield of potatoes.

Known patent No. 2140138 for a group of inventions "Method of pre-sowing treatment of seeds of vegetable crops and a method of obtaining a preparation for pre-sowing treatment of seeds of vegetable crops" with a priority of 13.11.98.

These methods are carried out using a biofungicidal preparation containing the bacterial strain Bacillus subtilis Ch-13 (deposited under the registration number VNIISKhM D-606), which has a pronounced antibiotic effect on all major phytopathogenic fungi: Fusarium, Rhizoctonium, Verticilla, living in the soil or on the surface seeds. At the same time, the bacteria form spores, which makes it possible to preserve them, the preparation based on them, and the seeds treated with this preparation without loss of bacterial viability for up to 6 months.

EFFECT: inventions make it possible to increase the effectiveness of protection of vegetable crops from phytopathogenic fungi by means of pre-sowing seed treatment.

Known patent No. 2259397 for the invention "Means for protecting grain crops, sunflower, grapes from phytopathogenic microorganisms, and vegetable crops from phytopathogenic bacteria" according to application No. 2003110469 dated April 2, 2003, published on August 17, 2005, IPC: C 12 N 1/20 (C 12 N 1/20, C 12 R 1/25), A 23 K 3/00 (prototype).

In the previously known bacterial strain Bacillus subtilis Ch-13, antagonistic properties with respect to pathogens of agricultural crops were identified and experimentally established. In particular, the effectiveness of the strain against late blight ( Phytophtora infestans ), rhizoctoniosis ( Rhizoctonia solani ), Fusarium wilt ( Fusarium oxysporum ) has been confirmed for potatoes. It was also experimentally shown that the use of the bacterial strain Bacillus subtilis Ch-13, the producer of the biological product Extrasol, leads to an increase in the yield of grain crops and potatoes by an average of 30%.

The objective of the invention is to identify a new strain suitable for use in agriculture as a means to combat rhizoctoniosis on potatoes, as well as to expand the arsenal of such tools.

This problem is solved due to the fact that a new strain of bacteria Bacillus amyloliquefaciens P20 is used as a means to combat rhizoctoniosis on potatoes.

The strain of endophytic spore bacteria " Bacillus amyloliquefaciens P20" was isolated from the internal tissues of potato ( Solanum tuberosum L.), variety "Sudarynya", Leningrad region and deposited on April 7, 2022 in the Network Bioresource Collection in the field of genetic technologies for agriculture (RCAM) in FGBNU VNIIShM under the registration number RCAM 05515. A certificate of deposit of the strain is attached.

The strain is characterized by the following morphological-cultural and physiological-biochemical features.

The cells are shaped like regular rods with rounded ends and a monopolar peritrichous arrangement of flagella. Cell size 1.3 x 2.6 µm. The strain forms spores located in the center of the cell, positively stained by Gram.

On nutrient agar, it forms wrinkled colonies of white color, stretching consistency with uneven jagged edges. The diameter of the colonies is 12-15 mm. The optimum temperature for growth is 36 ⁰ C. At temperatures above 45 ⁰ C and less than 15 ⁰ C, growth is slow. The optimum pH of the medium is 7.3; growth also occurs at a pH of 4.5 to 8.0.

As the only source of carbon, the strain uses glucose, mannitol, galactose, fructose, maltose, sorbitol, arabinose, xylose, glycerol, starch with the formation of alkali, dulcitol with the formation of acid.

The strain uses mineral forms of nitrogen - ammonium salts and nitrates, amino acids and proteins.

The Bacillus amyloliquefaciens P20 bacterium strain is grown on an available nutrient medium consisting of molasses and corn extract, which is an advantage over, for example, the cultivation of Pseudomonas, which requires scarce and expensive nutrient media.

In accordance with the "Guidelines of the Ministry of Health of the USSR" No. 2620-82 and No. 4263-87, it was experimentally determined that the bacterial strain Bacillus amyloliquefaciens P20 is non-virulent, non-toxic and non-toxigenic, belongs to the 4th hazard class.

In the Bacillus amyloliquefaciens P20 bacterium strain, the ability to suppress the development of rhizoctoniosis on potatoes due to the production of fungicidal substances in the nutrient medium during the cultivation of bacteria was revealed and experimentally confirmed.

It has been experimentally established that the strainBacillus amyloliquefaciensP20 has fungicidal action against phytopathogenic fungiFusarium oxysporum, Fusarium graminearum, Fusarium sporotrichioidesAndRhizoctonia solani.

To determine the fungicidal activity of the strain of bacteria Bacillus subtilis Ch-13 (producer of the biological fungicide BisolbiSan, registered against rhizoctoniosis in the Ministry of Agriculture of the Russian Federation) - the prototype and the claimed strain of Bacillus amyloliquefaciens P20, the method of "wells" was used. The following phytopathogenic fungi were selected for testing: Fusarium oxy-sporum, Fusarium graminearum, Fusarium sporotrichioides and Rhizoctonia solani. Potato dextrose agar (PDA, Sigma-Aldrich, USA) heated and cooled to a temperature of 40°C was supplemented with a suspension of spores of one of the above phytopathogenic fungi ( ¹⁰⁵ CFU/ml) at the rate of 1 μl of the suspension per 1 ml of medium. The resulting mixture with each of the mushrooms was poured into a separate Petri dish. After the mixture solidified, 3 even through holes were made in it with a calcined cork drill: 100 μl of a bacterial suspension based on the prototype strain of Bacillus subtilis Ch-13 with a cell titer of 10 ⁸ CFU / ml was poured into one, and a suspension based on the claimed Bacillus strain was poured into the other amyloliquefaciens P20 with the same cell titer, and distilled water was poured into the third hole (control). All cups with "wells" were cultivated for 72-96 hours at t 25 ⁰ C. The fungicidal activity of the strains was determined by the zone of inhibition of fungal growth around the "wells".

The measurement results are presented in Table 1.

Table 1. Zones of inhibition of growth of various phytopathogenic fungi

Experience option with
"wells" Diameter of the fungus growth suppression zone, mm F. oxysporum F. graminearum F.sporotrichioides Rhizoctonia solani Control (water) 0 0 0 0 Bacillus subtilis Ch-13
(prototype) 11.3±0.7 15.9±1.1 7.1±0.5 5.7±0.5 Bacillus amylolique-
faciens P20 (new) 18.3±1.5 34.5±2.3 13.7±1.0 11.5±0.9

From the data given in Table 1 it can be seen that the claimed bacterial strain Bacillus amyloliquefaciens P20 has a stronger fungicidal effect against phytopathogenic fungi Fusarium oxysporum, Fusarium graminearum, Fusarium sporotrichioides and Rhizoctonia solani compared to the prototype strain of Bacillus subtilis Ch-13 (fungicide against rhizoctoniosis and fusarium, registered by the Ministry of Agriculture of the Russian Federation), increasing the diameter of the zone of inhibition of fungal growth by 5.8-18.6 mm.

To determine the fungicidal activity of the prototype strain of Bacillus subtilis Ch-13 and the proposed strain of Bacillus amyloliquefaciens P20, depending on the concentration of their suspensions, the method of "wells" was used. A suspension of spores of the phytopathogenic fungus Phytophthora infestans 1841 with a titer of ¹⁰⁵ CFU/ml was added to potato dextrose agar (PDA, Sigma-Aldrich, USA) heated and cooled to a temperature of 40°C at the rate of 1 μl of the suspension per 1 ml of medium. The resulting mixture was poured into two Petri dishes. In each Petri dish, after the mixture had solidified, 3 through holes were made in it with a calcined cork drill. In one cup, 100 μl of a suspension based on the prototype strain of Bacillus subtilis Ch-13 with a titer of 10 ⁸ CFU/ml in varying degrees of dilution (100%, 10% and 0.5%) was poured into these holes, and in the other cup - 100 μl of a suspension based on the claimed strain of Bacillus amyloliquefaciens P20 with the same cell titer of 10 ⁸ CFU/ml and with the same options for the degree of dilution of the suspension (100%, 10% and 0.5%). Cups with "wells" were cultivated for 72 hours at t 28 ⁰ C.

The fungicidal activity of the prototype strain Bacillus subtilis Ch-13 and the proposed strain Bacillus amyloliquefaciens P20, depending on the concentration of their suspensions, was determined by the size of the zone of inhibition of the growth of the phytopathogenic fungus Phytophthora infestans 1841 around the "wells" with a bacterial suspension of the appropriate concentration.

The measurement results are presented in Table 2.

Table 2. Zone of inhibition of growth of phytopathogenic fungusPhytophthora

infestans 1841 depending on suspension concentration

different strains of bacteria (prototype and claimed)

Experience option with
"wells" Zone of inhibition of growth of phytopathogenic fungus, mm Undiluted suspension (100%) Suspension in dilution 1:10 (10%) Suspension diluted 1:200 (0.5%) Bacillus subtilis Ch-13
(prototype) 11.3±1.1 11.5±1.0 11.5±0.7 Bacillus amylolique-
faciens P20 (new) 19.5±1.3 18.5±1.1 18.5±0.9

From the data given in Table 2, it can be seen that in all variants of dilution of the bacterial suspension, the claimed bacterial strain Bacillus amyloliquefaciens P20 inhibits the growth of the mycelium of the phytopathogenic fungus Phytophthora infestans 1841 much more effectively compared to the prototype strain of Bacillus subtilis Ch-13, increasing the zone oppression by 7.0-8.2 mm.

Below are examples of the manufacture of a microbiological preparation based on the Bacillus amyloliquefaciens P20 strain.

Example 1

A culture of bacteria Bacillus amyloliquefaciens P20 was grown in a liquid sterile nutrient medium containing:

4% wheat bran and 0.3% chalk,

on a shaker or in a fermenter at 34±1°C for 30-42 hours until the culture fluid reaches a titer of at least 10 ⁹ cells/ml and a spore content of at least 95%. Then a liquid form of the microbiological preparation was obtained in the following way: 40% of the culture liquid and 60% of water were mixed (the titer of the preparation was at least 3⋅10 ⁸ cells/ml). The resulting liquid form was kept for 3-5 days at t 20-25°C to obtain a bacterial titer of at least 3⋅10 ⁸ CFU per 1 ml of the drug, after which the drug is ready for use. The liquid preparation was sterilely poured into polyethylene bottles or canisters with a capacity of 0.25; 0.5; 1.0 and 10.0 liters, which were pre-rinsed with alcohol.

Example 2

A culture of bacteria Bacillus amyloliquefaciens P20 was grown in a liquid sterile nutrient medium of the following composition:

Molasses - 25 g/l,

corn extract - 12.5 g/l,

MgSO ₄ x7H ₂ O - 0.25 g / l,

CaCl ₂ x2 H ₂ O - 1 g / l,

MnSO ₄ - 0.1 g / l,

FeSO ₄ - 0.0001 g / l,

CuSO ₄ - 0.0001 g/l

on a shaker or in a fermenter at 34±1°C for 24-42 hours until the culture liquid reaches a titer of at least 3⋅10 ⁹ cells/ml and a spore content of at least 95%. After that, a liquid form of a microbiological preparation was obtained by mixing 20% of the culture liquid and 80% of water (the titer of the preparation was at least 3·10 ⁸ cells/ml). Next, the liquid preparation, ready for use, was poured into polyethylene bottles or canisters with a capacity of 0.25; 0.5; 1.0 and 10.0 liters, which were pre-rinsed with alcohol.

Due to the relatively high biological activity of the strain and its high growth rate, the liquid preparation in production and in the finished form is practically not infected with foreign microflora. Nevertheless, in any variant of obtaining a biological product based on a strain of the bacterium Bacillus amyloliquefaciens P20, constant monitoring of all stages is necessary.

The degree of biological protection of potatoes from rhizoctoniosis was studied in field experiments in the Leningrad region, Volosovsky district, in the fields of AgroInter LLC, when growing seed potatoes of high reproductions of Charoit and Gusar varieties. The experiments were carried out using the BisolbiSan fungicide (biological standard against rhizoctoniosis (“STATE CATALOG OF PESTICIDES AND AGRICULTURAL CHEMICALS”, approved for use on the territory of the Russian Federation, 2022) - a producer of the Bacillus subtilis Ch-13 strain and a preparation based on the claimed Bacillus amyloliquefaciens P20 strain.

Field experiments with potato varieties Charoit and Gusar were carried out under the same conditions, using the following options:

1) in the control variant, no treatment was performed;

2) chemical fungicides and fungicidal disinfectants were used (tuber treatment - Celeste Top, KS + Uniform, consumption 0.4 l/t + 1.2 l/t; vegetation treatment - Infinito, KS, consumption 1.2 l/ha; Rapid Duet, SP, consumption 2.0 kg/ha; Mancozeb, SP, consumption 1.5 kg/ha; Buzzer, SC, consumption 0.3 l/ha; Dry wind, VR + Infinito, SC, consumption 2.0 kg /ha + 1.2 l/ha);

3) treatment was carried out with the microbiological fungicide BisolbiSan - the producer of the strain - the prototype of Bacillus subtilis Ch-13 (treatment of tubers - BisolbiSan, Zh + Cruiser, KS, consumption 15 l / t + 0.2 l / t; treatment for vegetation - BisolbiSan, Zh , consumption 10.0 l/ha - 5 times per season);

4) treatment was carried out with a preparation based on the claimed bacterial strain Bacillus amyloliquefaciens P20 (all types of treatment are the same as in experiment 3) when treated with a biological standard).

Phytopathological records of the results obtained during the period of budding of potato tops were carried out according to generally accepted methods (Guidelines for registration tests of fungicides in agriculture / edited by V.I. Dolzhenko. - St. Petersburg, 2009. - 377 p.).

The results of experiments with potatoes varieties Charoit and Gusar are in Table 3, 4.

Table 3. Results of taking into account the degree of damage to potatoes of the Charoit variety

rhizoctoniosis during budding

Experience Variant Development of the disease, score Biological efficiency,% stems stolons stems stolons Control without processing 1.3 1.5 - - The use of chemical fungicides and fungicidal protectants 1.2 1.13 7.7 24.6 Processing BisolbiSan
(biological standard),
PC. Bacillus subtilis Ch-13 1.2 1.33 7.7 11.3 Treatment with the drug
the basis of a new piece. bacillus
amyloliquefaciens P20 1.06 1.3 18.4 13.3

Table 4. The results of taking into account the degree of damage to the potato variety Gusar

rhizoctoniosis during budding

Variant of experience Development of the disease, score Biological efficiency,% stems stolons stems stolons Control without processing 1.23 2.26 - - The use of fungicides and fungicidal protectants 1.03 2.1 16.3 7.1 Processing BisolbiSun
(biological standard),
pcs . Bacillus subtilis Ch-13 1.1 1.9 10.5 15.9 Treatment with a preparation based on a new piece. Bacillus amyloliquefaciens P20 1.03 1.7 18.4 24.8

From the data given in Tables 3 and 4, it can be seen that the treatment of tubers and plants of potato varieties Charoit and Gusar with a preparation based on the claimed strain of Bacillus amyloliquefaciens P20 is more effective than using the BisolbiSan biological standard based on the prototype strain of Bacillus subtilis Ch-13 and comparable to the effectiveness of using chemical fungicides and protectants.

The impact of the claimed strainBacillus amyloliquefaciens P20 on the yield of potatoes of the Charoit variety was studied during a field experiment in the Leningrad region, Volosovsky district, on the fields of AgroInter LLC. The soil is soddy-podzolic, medium loamy, medium cultivated, with the following agrochemical indicators of the arable layer: pH_Sol.- 6.5, the content of mobile phosphorus P₂ABOUT₅ - 11.4 mg / 100 g, exchangeable K₂O - 11.2 mg/100 g of soil. The content of organic matter is 3.7%. Predecessor - barley, potato crop rotation. The soil preparation system of the experimental plot included the main, or autumn, and pre-planting treatments. After harvesting the previous crop, autumn plowing was carried out to the full depth of the arable layer (18-20 cm). In the spring, when the physical ripeness of the soil occurred, the plowing of the fallow land was carried out to the same depth, and then cultivation with simultaneous harrowing. Mineral fertilizers in the form of azophoska (NPK 16:16:16) were applied at planting at a rate of 300 kg/ha in physical weight (46 kg/ha of a.i.); kalimag (300 kg/ha in physical weight) was applied for cultivation; ammonium sulfate (200 kg / ha in physical weight) - for hilling. Planting care consisted of two pre-emergence and two inter-row (loosening and hilling). Three weeks before harvesting, chemical desiccation with Golden Ring was carried out. Harvesting was carried out manually and with a Grimme DR 1500 potato harvester, after preliminary chemical desiccation of the tops with Golden Ring, BP at a rate of 2.0 l/ha.

The treatment of tubers with chemical and biological disinfectants was carried out stationary, in order to improve the quality of their coating. The dressing unit was manufactured according to an individual project by the Institute of Agroengineering and Environmental Problems of Agricultural Production and is a chamber with nozzles mounted on a potato loader (a branch of the Federal State Budget Scientific Institution "Federal Scientific Agroengineering Center VIM"). The flow rate of the working fluid was 14 l/t of seeds. After processing, potato tubers were placed in nets and taken out into the open air to dry.

In the experiment, we used options for processing potato tubers:

1. Control - without processing.

2. Chemical disinfectant Emesto Silver is a translaminar fungicide against a complex of soil-dwelling fungi that cause rhizoctoniosis, fusarium, silver scab and anthracnose.

3. Processing of BisolbiSan (bioetalon) based on Bacillus subtilis Ch-13 strain and products of its metabolism with a titer of class producer 5 10 ⁸ CFU/ml

(according to the "State Catalog of Pesticides and Agrochemicals Allowed for Use on the Territory of the Russian Federation" is registered for the fight against rhizoctoniosis, late blight and alternariosis on potatoes as a fungicide and disinfectant for planting material).

4. Treatment with a preparation based on the claimed strain of Bacillus amyloliquefaciens P20 and its metabolic products with a cell titer of 5⋅10 ⁸ CFU/ml.

All treatments of potato tubers of the Charoit variety were carried out with a chemical disinfectant and biological preparations in the same way in all variants of the experiment.

The results of the experiment are presented in Table 5.

Table 5. The yield of potatoes of the Charoit variety, depending on the processing

Option Yield, cf. values, t/ha Control Gain T % Control - no processing 20.34 - - Chemical treatment
protectant (Emesto Silver) 17.66
-2.68 -13.7 Processing BisolbiSan
(biological standard),
PC. Bacillus subtilis Ch-13 21.7 +1.36 +6.7 Treatment with a preparation based on pcs. Bacillus amyloliquefaciens P20
(new) 23.66 +3.32 +16.3

From the data given in Table 5 it can be seen that as a result of the use of the drug based on the claimed strain of Bacillus amyloliquefaciens P20, the yield of potato tubers of the Charoit variety increased by an average of 3.32 tons or 16.3% compared with the control and by 1.96 tons or 9.0% compared with the BisolbiSan biological standard based on the prototype strain Bacillus subtilis Ch-13, not to mention the yield indicators when the tubers are treated with a chemical disinfectant (Emesto Silver).

That is, the treatment of potato tubers of the Charoit variety with a preparation based on the Bacillus amyloliquefaciens P20 strain has a better effect not only on suppressing the development of rhizoctoniosis, but also on increasing its yield compared with the chemical disinfectant and BisolbiSan biological standard based on the Bacillus subtilis Ch-13 prototype strain .

Thus, as a result of the experiments, the ability of the bacterial strain Bacillus amyloliquefaciens P20 to inhibit the development of potato rhizoctoniosis and increase the yield of its tubers was revealed and experimentally confirmed.

It is also important that when using this strain in the composition of microbiological preparations, the bacteria Bacillus amyloliquefaciens P20 form spores, which makes it possible to preserve preparations based on them without loss of bacterial viability for a long period, at least 12 months.

The research results allow us to conclude that the titer (the number of viable cells and spores) of the Bacillus amyloliquefaciens P20 bacterium strain for its effective use in the composition of various microbial preparations should be 10 ⁵ -10 ⁹ cells/ml of culture fluid. Since it has been experimentally established that the use of a strain with a titer of less than 10 ⁵ cells / ml leads to a decrease in the effect of inhibition of potato rhizoctoniosis and stimulation of the growth of potato tubers, and an increase in titer over 10 ⁹ cells / ml does not increase the effectiveness of the protective action against rhizoctoniosis and increase productivity potatoes.

Thus, it was experimentally established that a new strain of endophytic spore bacteria Bacillus amyloliquefaciens P20, in which the ability to suppress the development of rhizoctoniosis on potatoes by producing fungicidal substances in the nutrient medium during the cultivation of bacteria, has been identified and experimentally confirmed, is suitable and promising for use in agriculture. as a means to combat potato rhizoctonia and allows you to expand the arsenal of such tools.

Claims (1)

The bacterial strain Bacillus amyloliquefaciens P20, deposited at the Federal State Budgetary Scientific Institution All-Russian Research Institute of Agriculture under the registration number RCAM 05515 as a tool for combating potato rhizoctoniosis, as well as expanding the arsenal of such tools.