NODULE FORMATION BY CLOVER-RHIZOBIUM CARRYING CHROMOSOMAL NOD GENES

Abstract

Plasmid pCINod1 carrying attP of a lysogenic rhizobiophage and the nod genes was constructed. Inoculation of a conjugation mixture of Escherichia coli harbouring pCINod1 and a nodulation-defective Rhizobium leguminosarum biovar trifolii strain resulted in formation of root nodules on white clover. Rhizobium transconjugant strain CNH1 isolated from these nodules had integrated pCINod1 into its chromosome. The light and electron microscopic observation of the nodulation process revealed that the nod genes on the chromosome of strain CNH1 were completely functional.