The role of lipochitooligosaccharides in root nodule organogenesis and plant cell growth.

Lipochitooligosaccharides (Nod signals) excreted by rhizobia induce the formation of symbiotic root nodules in leguminous plants. This process is host plant specific, depending on the structural modifications of Nod signals. Rapid responses of plant roots in single cell assays have provided powerful tools in dissecting Nod signal transduction pathways and in elucidating the molecular basis of host specificity. Recent findings indicate that lipochitooligosaccharides, as well as symbiosis-related genes, also function in non legumes, pointing to a general role for these elements in plant morphogenesis.