The plant as the genetic determinant of leghaemoglobin production in the legume root nodule

Abstract

1. 1. The question of whether plant or bacterium genetically specifies the type of haemoglobin produced in legume root nodules has been studied. 2. 2. Two dissimilar legumes, yellow lupin ( Lupinus luteus L.) and serradella ( Ornithopus sativus Brot.), were effectively nodulated by the same strain of Rhizobium lupini. The leghaemoglobins were extracted from both types of nodule, and anlysed by chromatography on DEAE-cellulose. Nodules of yellow lupin contained four distinct leghaemoglobins, while serradella nodules contained at least two and probably three leghaemoglobins. 3. 3. The leghaemoglobins from lupin nodules were shown to behave differently from those from serradella nodules during chromatography on DEAE-cellulose and during electrophoresis in polyacrylamide gels. 4. 4. When yellow lupins were nodulated by two different strains of R. lupini, the leghaemoglobin pattern produced was apparently the same for both strains, on the basis of chromatographic and electrophoretic behaviour. 5. 5. When serradella was nodulated by the same two strains of R. lupini, electrophoresis failed to show any differences in the haemoglobin pattern produced by the two different strains. 6. 6. The conclusion is drawn that the genetic specification of haemoglobins in legume root nodules is a property of the plant.