The effect of pH on the nodulation of Sinorhizobium fredii and Bradyrhizobium japonicum was examined by analy- zing the indigent soybean rhizobia,predominant indigent rhizobia,and specific rhizobia,respectively.The re...The effect of pH on the nodulation of Sinorhizobium fredii and Bradyrhizobium japonicum was examined by analy- zing the indigent soybean rhizobia,predominant indigent rhizobia,and specific rhizobia,respectively.The results showed that very acid and very alkaline environment could retard the nodulation and inhibit the growth of the rhizobia.Sinorhizohium fredii could endure environment more strongly than Bradyrhizobium japonicum,and had a high competitive nodulation capacity.Bradyhizobium japonicum could endure acid environment more strongly than Sinorhizobium fredii.In very acid and very alkaline environment,the nodulation capacity of S.fredii and B.japonicum was mainly determined by their physiological characteristics.展开更多
The symbiotic matching for nodulation of Bradyrhizobium japonicum strains is a synergy of multi-proteins and plays a key role in symbiotic nitrogen fixation in nature. Studies on mechanism of symbiotic matching are si...The symbiotic matching for nodulation of Bradyrhizobium japonicum strains is a synergy of multi-proteins and plays a key role in symbiotic nitrogen fixation in nature. Studies on mechanism of symbiotic matching are significant in both theory and practice. In this paper, B. japonicum USDA110-A with high symbiotic matching with high-oil content soybean cultivar Suinong 20 and B. japonicum 2178 with low symbiotic matching were selected for proteomic to reveal mechanism of different symbiotic nodulation. The results showed that the amount and categories of proteins identified in this test were different when the two strains were treated by symbiotic nodulation. There were 10 up-regulated proteins and 5 down-regulated proteins with significant difference for B. japonicum USDA110-A. Proteins associated with nodulation and metabolism of energy and material, which were propitious to symbiotic nodulation, were all up-regulated, such as PHDPS synthase, metal-dependent phosphohydrolase, glycosyl transferase family. In contrast, only 5 up-regulated and 7 down-regulated differential proteins were detected in B. japonicum 2178. Molecular chaperones and defensive proteins, which influence the folding of nascent polypeptide chains and the active of azotase were down-regulated. To a certain extent, the different responses of B. japonicum to daidzein were one of the most important reasons that cause varieties in symbiotic matching ability.展开更多
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
Bacterial strain RV9 recovered from greengram nodules tolerated 2400 μg/mL of hexaconazole and was identified by 16 S rDNA sequence analysis as Bradyrhizobium japonicum(KY940048). Strain RV9 produced IAA(61.6 μg/mL)...Bacterial strain RV9 recovered from greengram nodules tolerated 2400 μg/mL of hexaconazole and was identified by 16 S rDNA sequence analysis as Bradyrhizobium japonicum(KY940048). Strain RV9 produced IAA(61.6 μg/mL), ACC deaminase(51.7 mg/(protein·hr)), solubilized TCP(105 μg/mL), secreted 337.6 μg/mL EPS, and produced SA(52.2 μg/mL) and 2,3-DHBA(28.3 μg/mL). Exopolysaccharides produced by strain RV9 was quantified and characterized by SEM, AFM, EDX and FTIR. Beyond tolerance limit,hexaconazole caused cellular impairment and reduced the viability of strain RV9 revealed by SEM and CLSM. Hexaconazole distorted the root tips and altered nodule structure leading thereby to reduction in the performance of greengram. Also, the level of antioxidant enzymes, proline, TBARS, ROS and cell death was increased in hexaconazole treated plants.CLSM images revealed a concentration dependent increase in the characteristic green and blue fluorescence of hexaconazole treated roots. The application of B. japonicum strain RV9 alleviated the fungicide toxicity and improved the measured plant characteristics. Also,rhizobial cells were localized inside tissues as revealed by CLSM. Colonization of B.japonicum strain RV9 decreased the levels of CAT, POD, APX, GPX and TBARS by 80%, 5%,13%, 13% and 19%, respectively over plants grown at 80 μg/(hexaconazole·kg) soil. The ability to detoxify hexaconazole, colonize plant tissues, secrete PGP bioactive molecules even under fungicide pressure and its unique ability to diminish oxidative stress make B.japonicum an attractive choice for remediation of fungicide polluted soils and to concurrently enhance greengram production under stressed environment.展开更多
Protein fusion with the Escherichia coli alkaline phosphatase is used extensively for the analysis of the topology of membrane protein. Agrobacterium strain A6007 was mutagenized with E. coli strain mm294A plasmid pRK...Protein fusion with the Escherichia coli alkaline phosphatase is used extensively for the analysis of the topology of membrane protein. Agrobacterium strain A6007 was mutagenized with E. coli strain mm294A plasmid pRK609 having TnphoA to obtain mutants defective in virulence. Because alkaline phosphatase activity is only detected when the PhoA gene product from the transposon is secreted out of the protoplasm, the virulence mutants are located in genes that code for transmembrane or periplasmic proteins. Attempts were made to obtain the sequences adjacent to the TnphoA inserts through several different approaches including Inverse PCR, Cloning, and Tail PCR. Transposon-adjacent sequence was obtained from one membrane anchor subunit in Bradyrhizobium japonicum i.e. succinate dehydrogenase which has enhanced transformation efficiency.展开更多
The current study describes the molecular characterization of a clone which can restore the ability of bdh A mutant strains NGRPA2 and Rm11107 to utilize 3-hydroxybutyrate as a sole carbon source (Hbu+ ). This clone w...The current study describes the molecular characterization of a clone which can restore the ability of bdh A mutant strains NGRPA2 and Rm11107 to utilize 3-hydroxybutyrate as a sole carbon source (Hbu+ ). This clone was screened out by complementation experiment from Bradyrhizobium japonicum US-DAI 10 genomic library, and the presence of bdhA gene in the clone was verified by Bdh assay and Southern blot analysis. Furthermore, the entire sequence of bdhA. gene was sequenced and the sequence was deposited in GenBank database under the accession number AY077581. bdhA gene comprises 789 base pairs and encodes Bdh with 262 amino acid of MW 27.59 kDa. Interposon JlKm was inserted into the bdhA ORF at EcoR I site and the bdhA mutant was constructed in B .japonicum by homologous recombination. Plant assay result did not show obvious effects of mutation of bdhA gene on nodulation and nitrogen-fixation.展开更多
文摘The effect of pH on the nodulation of Sinorhizobium fredii and Bradyrhizobium japonicum was examined by analy- zing the indigent soybean rhizobia,predominant indigent rhizobia,and specific rhizobia,respectively.The results showed that very acid and very alkaline environment could retard the nodulation and inhibit the growth of the rhizobia.Sinorhizohium fredii could endure environment more strongly than Bradyrhizobium japonicum,and had a high competitive nodulation capacity.Bradyhizobium japonicum could endure acid environment more strongly than Sinorhizobium fredii.In very acid and very alkaline environment,the nodulation capacity of S.fredii and B.japonicum was mainly determined by their physiological characteristics.
基金supported by the National 863 Program of China (2010AA10A203)the Basic Scientific and Business Fund and Central Public Research Project, China (202-10)the Special Fund for Establishment of Modern Agri-cultural R&D System, Ministry of Agriculture, China(nycytx-004)
文摘The symbiotic matching for nodulation of Bradyrhizobium japonicum strains is a synergy of multi-proteins and plays a key role in symbiotic nitrogen fixation in nature. Studies on mechanism of symbiotic matching are significant in both theory and practice. In this paper, B. japonicum USDA110-A with high symbiotic matching with high-oil content soybean cultivar Suinong 20 and B. japonicum 2178 with low symbiotic matching were selected for proteomic to reveal mechanism of different symbiotic nodulation. The results showed that the amount and categories of proteins identified in this test were different when the two strains were treated by symbiotic nodulation. There were 10 up-regulated proteins and 5 down-regulated proteins with significant difference for B. japonicum USDA110-A. Proteins associated with nodulation and metabolism of energy and material, which were propitious to symbiotic nodulation, were all up-regulated, such as PHDPS synthase, metal-dependent phosphohydrolase, glycosyl transferase family. In contrast, only 5 up-regulated and 7 down-regulated differential proteins were detected in B. japonicum 2178. Molecular chaperones and defensive proteins, which influence the folding of nascent polypeptide chains and the active of azotase were down-regulated. To a certain extent, the different responses of B. japonicum to daidzein were one of the most important reasons that cause varieties in symbiotic matching ability.
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).
基金the financial support received in the form of UGC NonNET fellowship granted by University Grants Commission (D. O.No.F.1993/2006 (CU) dated 01.02.2007), New Delhi
文摘Bacterial strain RV9 recovered from greengram nodules tolerated 2400 μg/mL of hexaconazole and was identified by 16 S rDNA sequence analysis as Bradyrhizobium japonicum(KY940048). Strain RV9 produced IAA(61.6 μg/mL), ACC deaminase(51.7 mg/(protein·hr)), solubilized TCP(105 μg/mL), secreted 337.6 μg/mL EPS, and produced SA(52.2 μg/mL) and 2,3-DHBA(28.3 μg/mL). Exopolysaccharides produced by strain RV9 was quantified and characterized by SEM, AFM, EDX and FTIR. Beyond tolerance limit,hexaconazole caused cellular impairment and reduced the viability of strain RV9 revealed by SEM and CLSM. Hexaconazole distorted the root tips and altered nodule structure leading thereby to reduction in the performance of greengram. Also, the level of antioxidant enzymes, proline, TBARS, ROS and cell death was increased in hexaconazole treated plants.CLSM images revealed a concentration dependent increase in the characteristic green and blue fluorescence of hexaconazole treated roots. The application of B. japonicum strain RV9 alleviated the fungicide toxicity and improved the measured plant characteristics. Also,rhizobial cells were localized inside tissues as revealed by CLSM. Colonization of B.japonicum strain RV9 decreased the levels of CAT, POD, APX, GPX and TBARS by 80%, 5%,13%, 13% and 19%, respectively over plants grown at 80 μg/(hexaconazole·kg) soil. The ability to detoxify hexaconazole, colonize plant tissues, secrete PGP bioactive molecules even under fungicide pressure and its unique ability to diminish oxidative stress make B.japonicum an attractive choice for remediation of fungicide polluted soils and to concurrently enhance greengram production under stressed environment.
文摘Protein fusion with the Escherichia coli alkaline phosphatase is used extensively for the analysis of the topology of membrane protein. Agrobacterium strain A6007 was mutagenized with E. coli strain mm294A plasmid pRK609 having TnphoA to obtain mutants defective in virulence. Because alkaline phosphatase activity is only detected when the PhoA gene product from the transposon is secreted out of the protoplasm, the virulence mutants are located in genes that code for transmembrane or periplasmic proteins. Attempts were made to obtain the sequences adjacent to the TnphoA inserts through several different approaches including Inverse PCR, Cloning, and Tail PCR. Transposon-adjacent sequence was obtained from one membrane anchor subunit in Bradyrhizobium japonicum i.e. succinate dehydrogenase which has enhanced transformation efficiency.
文摘The current study describes the molecular characterization of a clone which can restore the ability of bdh A mutant strains NGRPA2 and Rm11107 to utilize 3-hydroxybutyrate as a sole carbon source (Hbu+ ). This clone was screened out by complementation experiment from Bradyrhizobium japonicum US-DAI 10 genomic library, and the presence of bdhA gene in the clone was verified by Bdh assay and Southern blot analysis. Furthermore, the entire sequence of bdhA. gene was sequenced and the sequence was deposited in GenBank database under the accession number AY077581. bdhA gene comprises 789 base pairs and encodes Bdh with 262 amino acid of MW 27.59 kDa. Interposon JlKm was inserted into the bdhA ORF at EcoR I site and the bdhA mutant was constructed in B .japonicum by homologous recombination. Plant assay result did not show obvious effects of mutation of bdhA gene on nodulation and nitrogen-fixation.
