Phaseolus vulgaris is a non-selective host for nodulation

Abstract

A systematic analysis of the symbiotic phenotype on <it>Phaseolus vulgaris</it> of tropical rhizobia isolated from a variety of leguminous plant species and of classified type strains from the genera <it>Rhizobium, Sinorhizobium, Mesorhizobium, Bradyrhizobium</it> and <it>Azorhizobium</it> was performed. Depending on the bean cultivar, between 80 and 90% of the tested rhizobia were able to nodulate. A minority of these nodules were also nitrogen-fixing. A detailed microscopic analysis of the induced nodules or nodular structures revealed that the interaction between these strains and <it>P. vulgaris</it> was arrested at different stages of the interaction. Our results show that <it>P. vulgaris</it> is able to perceive signals for nodulation from many rhizobia although most of the interactions are not effective.