摘要:
This invention provides useful promoters from the R. trifolii nifH gene for the construction of recombinant molecules to regulate foreign genes for expression under desired conditions. In particular, the promoters act to control expression of the foreign genes within root nodules formed by rhizobial bacterial strains in symbiotic combination with host plants.A rhizobium diagnostic segment (RDS) is also provided comprising a DNA segment found at more than one location in rhizobia, the RDS being species-specific, and detectable by DNA hybridization under stringent conditions. A recombinant plasmid comprising a RDS and a bacterial strain containing the plasmid are provided. Methods are provided for identifying species and strains of field isolates of Rhizobium, using RDS's. One RDS exemplified comprises 5' sequences from the R. trifolii nifH gene.
摘要:
The nifD promoter regions of Bradyrhizobium japonicum and Bradyhizobium sp. (Parasponia) have been sequenced and found to be significantly homologous. Recombinant DNA molecules comprising foreign genes under the control of such promoters are provided. Rhizobial species containing such recombinant constructions, either in plasmids or integrated into the genome, are provided. These are especially useful for expressing desired foreign genes within root nodules.
摘要:
The invention includes a consensus nucleotide sequence found in the promoter regions of those Rhizobium and Bradyrhizobium nodulation genes which are activated by chemical inducer(s) in legume exudate. A promoter comprising the consensus sequence is a legume exudate-inducible promoter. A recombinant gene comprising a structural gene and a legume exudate-inducible promoter is selectively expressed in the presence of legume exudate or chemical inducer(s) and a functional nodD gene. The consensus nucleotide sequence isATCCAYNNYGYRGATGNWYKYKATCSAAWCAATCRATTTTACCARWYYKNSRR whereN is A, G, C or TY is C or TR is A or GW is A or TK is G or T andS is C or G.
摘要:
The nifH promoter regions of Bradyrhizobium japonicum and Bradyrhizobium sp. (parasponia) have been sequenced and found to be significantly homologous. Recombinant DNA molecules comprising foreign genes under the control of such promoters are provided. Rhizobial species containing such recombinant constructions, either in plasmids or integrated into the genome, are provided. These are especially useful for expressing desired foreign genes within root nodules.
摘要:
Nodulation gene-inducing factors have been isolated and identified. A number of substituted flavones, some of which are components of exudates and extracts of leguminous plants, have been found to induce expression of certain nodulation genes in Rhizobium strains. Three components of clover extract 7,4'-dihydroxyflavone, 7,4'-dihydroxy-3'methoxyflavone, and 4'-hydroxy-7-methoxyflavone have been identified as nodulation inducers of certain Rhizobium trifolii nod genes. A number of other flavonoids including flavones, flavanones, flavanols and dihydroflavanols, not necessarily found in legume exudates, were also found to induce expression of certain nodulation genes.
摘要:
This invention relates to the use of Nod factors and derivatives thereof for the modulation of blood vessel growth and development as well as compositions for modulating angiogenesis.