Rhizobium nodulation gene inducers

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... 

Peters, N.K. and Long, S.R., Rhizobium meliloti nodulation gene inducers and inhibitors. Plant Physiol, 88, 396, 1988. 

B. G. Rolfe, Flavones induce expression of nodulation genes in Rhizobium, Nature 323 632 (1986). 

Maxwell, C.A. et al., Molecular characterization and expression of isoliquiritigenin 2 -0-methyltransferase, an enzyme specifically involved in the biosynthesis of an inducer of Rhizobium meliloti nodulation genes. Plant J., 4, 971, 1993. 

Peters NK, Frost JW, Long SR. 1986. A plant flavone, luteolin, induces expression of Rhizobium meliloti nodulation genes. Science 233 977-980. 

The formation of root nodules associated with nitrogen fixation in legumes is an area of active study. Hormonal involvement in the developmental modifications needed to establish the nodule, has been reviewed [186]. Studies on the molecular characterization of nodulation have shown that early nodulation genes are induced by auxin transport inhibitors, and inhibitor treated roots produce pseudonodules [187]. Rhizobium species appear to produce lAA by a pathway involving the conversion of tryptophan to indole-... 

Ferret, X., Staehelin, C., William, J.B. (2000) Molecular basis of symbiotic promiscuity. Microbiol Mol Biol R. 64, 180-201 Persson, J. and Nasholm, T. (2001) Amino acid uptake a widespread ability among boreal forest plants. Ecol Lett. 4,434-438 Peters, N.K., Frost, J.W. and Long, S.R. (1986) A plant flavone, luteolin, induces expression of Rhizobium meliloti nodulation genes. Science 233,977-980... 

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