Functional redundancy of genes for sulphate activation enzymes in Rhizobium sp. BR816

A study was conducted on the isolation of the nodPQ genes from Rhizobium sp BR816, a broad-host-range bacterium related to Sinorhizobium meliloti. Plant inoculation analysis did not indicate differences between the mutant strain and the wild-type. Moreover, it appears that a third, functionally homologous locus complements mutations in the Nod factor sulphation genes. Southern blot analysis also indicates that this locus has genes necessary for the sulphation of amino acids.