The main goal of our research work is to search for nodule bacteria of local soybean varieties and to identify and study their nodule-forming properties. In the present study, soil samples from fields in the Tashkent,...The main goal of our research work is to search for nodule bacteria of local soybean varieties and to identify and study their nodule-forming properties. In the present study, soil samples from fields in the Tashkent, Andijan, Bukhara, Jizzakh, Kashkadarya, Navoi, Namangan, Samarkand, Surkhandarya, Syrdarya, Fergana, and Khorezm regions of Uzbekistan were studied for the formation of symbiotic nodules in local soybean varieties. Nodules formed only in the soils of the Tashkent region in the root systems of local soybean varieties (Madad, Sevinch, Dostlik, Parvoz, Gavkhar, Khasildar, Baraka, Tashkent, Uzbekistan-6, Tumaris, Nafis, Orzu) were formed from 22 to 40 nodule. Forty-one bacterial species belonging to the genus Bradyrhizobium were isolated from the nodules of the different varieties. The specificity, virulence, and symbiotic efficacy of 12 active nodule bacteria were compared in the local Madad, Sevinch, Dostlik, and Parvoz varieties. The root systems of these varieties formed from 2 to 14 symbiotic pink nodules 0.5 - 10 mm in size. Inoculation of the Madad and Dostlik varieties with their specific M5-1 and D24-1 nodule bacteria resulted in a symbiotic efficiency 46.6% - 54.4% higher than in uninoculated control plants. Notably, the foreign inoculum “Rizovit” (Kazakhstan), created on the basis of Bradyrhizobium japonicum, did not form any nodules on the roots of the local Uzbekistan varieties. The main reason for this may be the difference in the genetic origin of foreign soybean varieties and domestic Uzbekistan varieties. The nucleotide sequences of 16S rRNA genes of nodule bacteria M5-1, S7-2, D24-1, and P12-1 showed 97.07% similarity with the 16S rRNA genes of Bradyrhizobium japonicum PRY65 (AF239848.2) and 98.98% similarity with Bradyrhizobium japonicum PRY62 (AF239847.2).展开更多
In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing...In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.展开更多
文摘The main goal of our research work is to search for nodule bacteria of local soybean varieties and to identify and study their nodule-forming properties. In the present study, soil samples from fields in the Tashkent, Andijan, Bukhara, Jizzakh, Kashkadarya, Navoi, Namangan, Samarkand, Surkhandarya, Syrdarya, Fergana, and Khorezm regions of Uzbekistan were studied for the formation of symbiotic nodules in local soybean varieties. Nodules formed only in the soils of the Tashkent region in the root systems of local soybean varieties (Madad, Sevinch, Dostlik, Parvoz, Gavkhar, Khasildar, Baraka, Tashkent, Uzbekistan-6, Tumaris, Nafis, Orzu) were formed from 22 to 40 nodule. Forty-one bacterial species belonging to the genus Bradyrhizobium were isolated from the nodules of the different varieties. The specificity, virulence, and symbiotic efficacy of 12 active nodule bacteria were compared in the local Madad, Sevinch, Dostlik, and Parvoz varieties. The root systems of these varieties formed from 2 to 14 symbiotic pink nodules 0.5 - 10 mm in size. Inoculation of the Madad and Dostlik varieties with their specific M5-1 and D24-1 nodule bacteria resulted in a symbiotic efficiency 46.6% - 54.4% higher than in uninoculated control plants. Notably, the foreign inoculum “Rizovit” (Kazakhstan), created on the basis of Bradyrhizobium japonicum, did not form any nodules on the roots of the local Uzbekistan varieties. The main reason for this may be the difference in the genetic origin of foreign soybean varieties and domestic Uzbekistan varieties. The nucleotide sequences of 16S rRNA genes of nodule bacteria M5-1, S7-2, D24-1, and P12-1 showed 97.07% similarity with the 16S rRNA genes of Bradyrhizobium japonicum PRY65 (AF239848.2) and 98.98% similarity with Bradyrhizobium japonicum PRY62 (AF239847.2).
文摘In this work, local strains of phosphate-solubilizing microorganisms were isolated and identified from the wheat rhizosphere and exogenous acid phosphatase enzymes of locally active phosphate- and potassium-mobilizing rhizobacteria belonging to the genera Escherichia, Rahnella, Bacillus, Enterobacter, Pseudomonas, and Pantoea were studied. The efficiency of the physiological properties of rhizobacteria is determined by the production of soluble phosphorus, and the amount of phosphorus depends on the activity and biomass of bacteria that secrete phosphorus. This is done by phosphate solubilizing bacteria, and the habitat ecosystem is enriched with beneficial micronutrients. In these studies, active rhizobacteria activity of acid phosphatase in nutrient liquid was studied at different temperatures. Optimum pH activity index and temperature variability of enzymes were determined. It should be noted that in the most active phosphate-solubilizing strains the maximum enzymatic activity was observed in the culture fluid of R. aquatilis strain 17, which produced 1.086 μmol p-nitrophenol μmol/min/ml. P. agglomerans 22, P. agglomerans 20 and Ps. kilonensis 32 cultures phosphatase activity was 0.143 - 0.680 p-nitrophenol μmol/min/ml. It should be noted that the phosphatase activity of bacteria belonging to the same genus and species was very different from each other. That is, the enzyme activity of Rahnella aquatilis strain 17 was 9 times higher than the enzyme activity of Rahnella aquatilis strain 9. The pH optimum of sour phosphatase enzymes in Rahnella aquatilis strain 16 was 6.0. The optimum temperature of acid phosphatase activity was 45˚C and 50˚C. The reason for this may be that the strains were isolated in different soil and climate conditions. When the acid phosphatase activity of R. aquatilis 3, 9, E. cloacae 8 and P. agglomerans 22 cultures was determined at a temperature of 45˚C, it was observed that the enzyme activity increased by 2 - 4 times. Es. hermannii 1, Ps. kilonensis 26 and B. simplex 28 bacteria acid phosphatase activity was not significantly affected by temperature rise.
