Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogen...Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.展开更多
GA-treated and non-treated G2 pea cDNAs were compared using a newly developed method called cDNA representational difference analysis (cDNA-RDA), and several GA-suppressed mRNAs were found. After cloning of the larger...GA-treated and non-treated G2 pea cDNAs were compared using a newly developed method called cDNA representational difference analysis (cDNA-RDA), and several GA-suppressed mRNAs were found. After cloning of the larger fragments PGAS1-3 ( pea GA-suppressed cDNA 1-3), they were demonstrated to be expressed only in pea tissue not treated with GA3 through Northern analysis. Compared with subtractive hybridization and differ-ential display techniques, this method not only can be easily manipulated but also has a relatively low rate of false posi-tive and is highly repetitive. It is the major progress in molecular cloning techniques.展开更多
Lectins and leghemoglobins in legumes play the important roles, respectively, in recognition of host plants to their own rhizobia, and lowering the oxygen partial pressure surround the bacteroids and protecting nitrog...Lectins and leghemoglobins in legumes play the important roles, respectively, in recognition of host plants to their own rhizobia, and lowering the oxygen partial pressure surround the bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen_fixing nodules.In order to investigate the non_leguminous recognition of rhizobial bacteria relating to nitrogen fixation, plant expression vectors containing pea lectin gene ( pl ) and Parasponia hemoglobin gene ( phb ) have been, respectively, constructed in a plasmid and the plasmid has been introduced into tobacco ( Nicotiana tabacum L.) using Agrobacterium tumefaciens (Smith et Townsend) Conn as a vehicle for transformation. PCR and Southern blot demonstrated that the two genes were integrated into the genome of the tobacco plants. Histochemical staining for GUS activity, Western blotting,and in situ hybridization of pea lectin showed that they were expressed at translational level in the plants. These results may provide a clue for exploring whether Rhizobium leguminosarum bv. viciae could extend its host range and make the transgenic tobacco plants have the possibility of being symbiotic, or associative to nitrogen fixation.展开更多
A major challenge for the management of gene banks is the maintenance of good seed health in the collections.Large germplasm collections >10 000 accessions often have been acquired from different sources over a ran...A major challenge for the management of gene banks is the maintenance of good seed health in the collections.Large germplasm collections >10 000 accessions often have been acquired from different sources over a range of dates,may differ in germination at time of deposition in the gene bank,and may have genetic differences in seed longevity.The major storage variables affecting seed longevity are temperature and seed moisture content.Two varieties of each pea(Pisum sativus L.),lentil(Lens culinaris Medikus subsp.culinaris),and chickpea(Cicer arietinum L.),were stored at three temperatures;40,20,and 2°C,each with three seed moisture levels of 10.9–13.8%(high),7.9–10.3%(medium),and 7–7.8%(low),in the Australian Temperate Field Crops Collection gene bank.Seed longevity at a given storage period was estimated by the corresponding germination percentage for each treatment.This paper is an interim report on seed viability decline in the first seven years of this seed longevity study,in which viability decline towards zero was almost completed in the three seed moisture treatments at 40°C and the 20°C high seed moisture treatment,but had not declined in the other treatments.Seed longevity positively responded to a reduction in temperature and then to a reduction in seed moisture.The number of days in storage for seed germination decline to 85%(p85),and to 50%(p50) for mean seed viability,are reported by storage/varietal treatment.Both p85 and p50 showed significant inverse linear responses with seed moisture at 40°C for pea and lentil varieties,with intra-specific variation for pea.This long term trial aims to provide informed timing of seed regeneration for accessions in a gene bank.展开更多
文摘Lectin and leghemoglobin in legumes play the important roles, respectively, in recognition of host plants to their rhizobial bacteria, and lowering the oxygen partial pressure around bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen-fixing nodules. In order to extend the host range of the rhizobial bacteria and to make them fix nitrogen in non-legumes, pea lectin gene (pl) and Parasponia hemoglobin gene ( phl,) have been constructed into a plant expression vector (pCBHUL) and the vector pCBHUL was introduced into rice calli from immature young embryos by particle bombardment. After the calli were regenerated into plantlets on the resistant-selecting media containing hygromycin, they were identified by PCR and Southern blot hybridization. It was indicated that the pi and phb genes were integrated into nucleic genome of the transformed rice plants. GUS activity and the product of the pi gene were determined by GUS staining, Western blot and in situ hybridization at translational level. Eighteen out of 40 plants resistant to hygromycin were positively identified by PCR analysis with the rate of 45%. The pi gene was expressed in 3 out of 18 plants with 17% and 7.5% in 40 plants. The results may provide a clue for exploring whether Rhizobium leguminosarum by. viceae could extend its host range and make the transgenic rice plants have the possibility of being symbiotic, or associative to nitrogen fixation.
文摘GA-treated and non-treated G2 pea cDNAs were compared using a newly developed method called cDNA representational difference analysis (cDNA-RDA), and several GA-suppressed mRNAs were found. After cloning of the larger fragments PGAS1-3 ( pea GA-suppressed cDNA 1-3), they were demonstrated to be expressed only in pea tissue not treated with GA3 through Northern analysis. Compared with subtractive hybridization and differ-ential display techniques, this method not only can be easily manipulated but also has a relatively low rate of false posi-tive and is highly repetitive. It is the major progress in molecular cloning techniques.
文摘Lectins and leghemoglobins in legumes play the important roles, respectively, in recognition of host plants to their own rhizobia, and lowering the oxygen partial pressure surround the bacteroids and protecting nitrogenase from oxygen in symbiotic nitrogen_fixing nodules.In order to investigate the non_leguminous recognition of rhizobial bacteria relating to nitrogen fixation, plant expression vectors containing pea lectin gene ( pl ) and Parasponia hemoglobin gene ( phb ) have been, respectively, constructed in a plasmid and the plasmid has been introduced into tobacco ( Nicotiana tabacum L.) using Agrobacterium tumefaciens (Smith et Townsend) Conn as a vehicle for transformation. PCR and Southern blot demonstrated that the two genes were integrated into the genome of the tobacco plants. Histochemical staining for GUS activity, Western blotting,and in situ hybridization of pea lectin showed that they were expressed at translational level in the plants. These results may provide a clue for exploring whether Rhizobium leguminosarum bv. viciae could extend its host range and make the transgenic tobacco plants have the possibility of being symbiotic, or associative to nitrogen fixation.
基金supported by the core budget for Australian Temperate Field Crops Collection(ATFCC)operationsjointly funded by the Government of Victoria and the Grains Research and Development Corporation of Australia
文摘A major challenge for the management of gene banks is the maintenance of good seed health in the collections.Large germplasm collections >10 000 accessions often have been acquired from different sources over a range of dates,may differ in germination at time of deposition in the gene bank,and may have genetic differences in seed longevity.The major storage variables affecting seed longevity are temperature and seed moisture content.Two varieties of each pea(Pisum sativus L.),lentil(Lens culinaris Medikus subsp.culinaris),and chickpea(Cicer arietinum L.),were stored at three temperatures;40,20,and 2°C,each with three seed moisture levels of 10.9–13.8%(high),7.9–10.3%(medium),and 7–7.8%(low),in the Australian Temperate Field Crops Collection gene bank.Seed longevity at a given storage period was estimated by the corresponding germination percentage for each treatment.This paper is an interim report on seed viability decline in the first seven years of this seed longevity study,in which viability decline towards zero was almost completed in the three seed moisture treatments at 40°C and the 20°C high seed moisture treatment,but had not declined in the other treatments.Seed longevity positively responded to a reduction in temperature and then to a reduction in seed moisture.The number of days in storage for seed germination decline to 85%(p85),and to 50%(p50) for mean seed viability,are reported by storage/varietal treatment.Both p85 and p50 showed significant inverse linear responses with seed moisture at 40°C for pea and lentil varieties,with intra-specific variation for pea.This long term trial aims to provide informed timing of seed regeneration for accessions in a gene bank.
