Nodulation nod genes

Other Nod genes provide for modifications that restrict infection to specific species of legumes. For example, nodS encodes a methyltransferase and nodU a carbomoyltransferase.65 NodH is a sulfotransferase.66 NodD is a transcriptional activator that binds to DNA and induces the synthesis of the other Nod factors needed to initiate nodulation.67 When an appropriate Nod factor is recognized, the root hairs on the legume... 

This rhamnan OPS is induced when the bacterium is cultured in the presence of flavonoids (molecules produced by die host legume that induce expression of die rhizobial nod genes) (Reuhs, et al., 2005), and a similar rhamnan was detected in bacteroids obtained from die host legume root nodule (Fraysse, et al., 2002, Jabbouri, et al., 1996). 

As discussed in Section 42.1.1, LCOs play a key role in the first step of symbiotic nitrogen fixation. They are molecular signals which induce NOD gene that regulates formation of nodules in leguminous plants at very low concentrations (Leronge 1990). This bioactivity of chitosan oligomers has also been demonstrated in experiments. 

Nodulating bacteria such as Rhizobium meliloti elaborate secreted nod factors, which are required for the infection and nodulation of appropriate legume plants. These factors are lipooligosaccharides based on pi,4 linked GlcNAc backbone [44]. In the case of R. meliloti, one of the nod genes involved in the elaboration of its nod... 

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