This sugar occurs both at the cell surfaces of Rhizobium trifolii and at the root hairs of Trifolium -species. They are unable to infect clover or to induce the production of nodules. Rhizobium japonicum is characterized by its exposed galactosyl-residues. Infection Nodule bacteria are mobile. They find the rhizosphere of plants chemotactically.
Phenolic compounds secreted by the roots, e.g. luteolin, serve as signals.
Here, too, both components seem to be necessary for nodulation. They display their effects only in their original species, i.e. they are unable to complement the respective genetic defect of another bacterial species. NodRm-1 seems to elicit root hair deformation directly. The structure of nodRm-1 is new. Three of the four sugar groups are N-acetylated.