Nod gene-inducer

Rao JR, JE Cooper (1994) Rhizobia catabolize nod gene-inducing flavonoids via C-ring fission mechanisms. J Bacterial 176 5409-5413. 

According to Hungria and Stacey (31) more than 4000 flavonoids have been identified within the plant kingdom and some of them have been recognized as nod gene-inducers (Table 1). In addition, root flavonoids have been suggested as molecular signals for the initiation and development of mycorrhizal infection (Chaps. 7 and 9). 

The basic structures of flavanones, flavones, and isoflavones together with coumestrol, an intermediate in the phenylpropane metabolism, are given in Fig. 2. The 3,5,7,3 -tetrahydroxy-4 -methoxyflavanone is a nod gene inducer in Rhizo-bium leguminosarum bv. viciae the 3, 4, 5,7-tetrahydroxyflavone, in Rhizobium ineliloti and 4,7-dihydroxyisoflavone, in Bradyrhizobium japonicum. Coumestrol, an intermediate in phenylpropane metabolism, is only a weak inducer (7). 

M. C. Bolanos-Vasquez and D. Werner, Effects of Rhizohium tropici, R. etii, and R. leguminosarum bv. phaseoU on nod gene-inducing flavonoids in root exudates of Phaseohis vulgaris. Molec. Plant Microbe Interact. 10 229 (1997). 

U. A. Hartwig, C. A. Maxwell, C. M. Joseph, and D. A. Phillips, Interactions among flavonoid nod genes inducers released from alfalfa seeds and roots. Plant Phy.siol 97 1138 (1989). 

Some nod Gene Inducers Released by Different Legumes... 

Hungria, M., Joseph, C.M., and Phillips, D.A., Rhizobium nod gene inducers exuded naturally from roots of common bean Phaseolus vulgaris L.), Plant Physiol, 97, 759, 1991. 

Leon-Barrios, M. et al.. Isolation of Rhizobium meliloti nod gene inducers from alfalfa rhizosphere soil, Appl Environ. Microbiol, 59, 636, 1993. 

Hartwig, U.A. and Phillips D.A., Release and modification of nod-gene-inducing flavonoids from alfalfa seeds. Plant Physiol, 95, 804, 1991. 

Bolanos-Vasquez, M.C. and Werner, D., Effects of Rhizobium tropici, R. etli, and R. legumino-sarum bv. phaseoli on nod gene-inducing flavonoids in root exudates of Phaseolus vulgaris. Mol Plant-Microbe Interact., 10, 339, 1997. 

Gagnon H, Ibrahim RK. Aldonic acids a novel family of nod gene inducers of Mesorhizobium loti, Rhizobium lupini, and Sinorhizobium meliloti. Mol. Plant-Microbe Interact. 1998 11 988-998. 

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