Nodulation gene products

A. Nodulation genes—production of nod factors Flavonoids Rhizobium spp. 90,91.92... 

Table 2 Biochemical Function of Nodulation Gene Products Involved in Nod Fiictor Synthesis and Transport...

Z. Banfalvi and A. Kondorosi, Production of root hair deformation factors by Rhizohium meliloti nodulation genes in Escherichia coli H.mD (NocM) is involved in the plant host-specific modification of the NodABS-factor. Plant Mol. Biol. 13 1 (1989). 

Nevertheless, cereal plants can interact with endosymbionts, capable of nitrogen fixation in other species, and be stimulated in their productivity. The odds of soil life are balanced for some bacteria by their interactivity at rhizosphere level, and a realm of exchanged signals dictates entry into hormonally reprogrammed root sites. Specificity for partner plant species is part of a fine speciation process that actively involves the bacterial nodulation genes, and continues to drive their variation dynamics. 

Recently, a new polyketide biosynthetic pathway in bacteria that parallels the well studied plant PKSs has been discovered that can assemble small aromatic metabolites.8,9 These type III PKSs10 are members of the chalcone synthase (CHS) and stilbene synthase (STS) family of PKSs previously thought to be restricted to plants.11 The best studied type III PKS is CHS. Physiologically, CHS catalyzes the biosynthesis of 4,2, 4, 6 -tetrahydroxychalcone (chalcone). Moreover, in some organisms CHS works in concert with chalcone reductase (CHR) to produce 4,2 ,4 -trihydroxychalcone (deoxychalcone) (Fig. 12.1). Both natural products constitute plant secondary metabolites that are used as precursors for the biosynthesis of anthocyanin pigments, anti-microbial phytoalexins, and chemical inducers of Rhizobium nodulation genes.12... 

Horvath B., Bachem, C.W.B., Schell, J. Kondorosi, A. (1987). Host-specific regulation of nodulation genes in Rhizobium is mediated by a plant-signal interacting with the nodD gene product. The EM BO Journal 6, 841-8. 

P. Mavingui, T. Laeremans, M. Flores, D. Romero, E. Martinez-Romero, and R. Palacios, Genes es.sential for nod factor production and nodulation are located on a symbiotic amplicon (AMP/ rrCEN299pc60) in Rhizobium tropici. J. Bacteriol. 180 2866-2874 (1998). 

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