Restriction of host range by the sym2 allele of Afghan pea is nonspecific for the type of modification at the reducing terminus of nodulation signals

Microbial Biotechnolog

Nod Factors of Rhizobium leguminosarum bv. viciae and Their Fucosylated Derivatives Stimulate a Nod Factor Cleaving Activity in Pea Roots and Are Hydrolyzed In Vitro by Plant Chitinases at Different Rates

Nod factors (NFs) are rhizobial lipo-chitooligosaccharide signals that trigger root nodule development in legumes. Modifications of NF structures influence their biological activity and affect their degradation by plant chitinases. Nodulation of certain pea cultivars by Rhizobium leguminosarum by. viciae requires modification of NFs at the reducing end by either an O-acetyl or a fucosyl group. Fucosylated NFs were produced by an in vitro reaction with NodZ fucosyltransferase and purified. Their biological activity on pea was tested by measuring their capacity to stimulate the activity of a hydrolase that cleaves NFs, Nonmodified and fucosylated NFs displayed this activity at nano- to picomolar concentrations, while a sulfated NF from Sinorhizobium meliloti was inactive. In an additional series of experiments, the stability of non-modified and fucosylated NFs in the presence of purified tobacco chitinases was compared. The presence of the fucosyl group affected the degradation rates and the accessibility of specific cleavage sites on the chitooligosaccharide backbone. These results suggest that the fucosyl group in NFs also weakens the interaction of NFs with certain chitinases or chitinase-related proteins in pea roots.Microbial Biotechnolog

Comparison of characteristics of the nodX genes from various Rhizobium leguminosarum strains

Microbial Biotechnolog

Structure, functions and perspectives of practical application of the signal molecules inducing development of rhizobia-legume symbiosis

Soil bacteria rhizobia establish nitrogen-fixing symbiosis with legume plants. Mutual recognition of symbiotic partners and initiation of nodule formation occur via exchange by molecular signals secreted both by plant and bacteria. This review summarizes recent data about structural diversity, genetic control of biosynthesis and functional role of Nod-factors. The possibilities of practical application of flavonoids and Nod-factors in agriculture are discusse