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

Pea (Pisum sativum) genes involved in symbiosis with nitrogen-fixing bacteria.1.Analysis of the expression of the early nodulin gene ENOD12 using the polymerase chain-reaction

The polymerase chain reaction (PCR) was used to detect the transcription products of the early nodulin gene in the pea. Single-stranded DNA copies were prepared using a primer corresponding to the terminal part of a previously sequenced cDNA clone and a total RNA isolate. The presence of amplification products was detected using Southern hybridization. Expression of the ENOD12 gene was found to occur at the earliest developmental stages of the symbiosis between the pea and nitrogenfixing bacteria, and occurred in root hair cell. Transcription activation required sufficient levels of activity of a limited number of symbiotic bacterial genes, namely nodDABC and nodE. Expression of ENOD12 was inducible by a soluble component excreted into the medium by activated bacteria, and by inhibitors of soluble hormone (auxins) transport. The ENOD12 gene was shown to lack introns

Endophytic Bacteria in Microbial Preparations that Improve Plant Development.

Microbial Biotechnolog

Genetic variability in tolerance to cadmium and accumulation of heavy metals in pea (Pisum sativum L.)

International audienc

Isolation of pea (Pisum sativum) mutants impaired in arbuscular mycorrhiza development, using a direct screening

International audienc