Little is known regarding why some strains of rhizobia fail to form successful symbiotic associations with leguminous crop plants. Melino et al. compare incompatible (no N2–fixation) and poorly compatible (reduced N2–fixation) associations between four genotypes of clover (Trifolium spp.) and four strains of Rhizobium leguminosarum bv. trifolii and assess symbiotic effectiveness by a variety of measures. They find three major responses to incompatibility, namely failed bacterial endocytosis from infection threads into plant cortical cells, bacteroid differentiation that aborts prematurely, and a reduced pool of functional bacteroids as a result of premature senescence. Thus poor plant growth responses resulting from nodulation by incompatible strains can now be linked to specific morphological aberrations.
- Next story Origins of determinate growth habit in Phaseolus
- Previous story Fruit load modulates flowering-related gene expression
New in Annals of Botany