A REVISION ON THE NUMBER AND STRUCTURES OF LIPOCHITIN OLIGOSACCHARIDES NODULATIONS SIGNALS FROM RHIZOBIUM TROPICI CIAT 899

摘要

Rhizobia are nitrogen-fixing bacteria that are able to invade the roots of leguminous plants and trigger the formation of the nodule that contains the nitrogen-fixing microsymbiont. During the symbiotic process, the host plant roots secrete flavonoids that induce the rhizobial nodulation genes (nod, nol and noe genes). These genes have been shown to be involved in the synthesis and secretion of bacterial nodulation signals called Nod factors or lipo-chitin oligosaccharides (LCOs). The nodulation factors consist of a backbone of three to five GlcNAc residues, bearing an amide-bound fatty acyl residue on the non-reducing terminal GlcN residue. This basic structure has structural variations that determine the host-specificity. We have described the structures of the LCOs produced by Rhizobium tropici CIAT899 [1]. In this paper we identified 16 LCOs having the following structures