Editing Nod factor (section)

== Nodulation ==
Rhizobia bind to host specific lectins present in root hairs which together with Nod factors lead to the formation of nodulation. Nod factors are recognized by a specific class of [[Receptor (biochemistry)|receptor]] [[kinase]]s that have  [[LysM domain]]s in their extracellular domains. The two LysM (lysin motif) receptor kinases ([[NFR1]] and [[NFR5]]) that appear to make up the Nod factor receptor were first isolated in the [[model organism|model]] legume ''[[Lotus japonicus]]'' in 2003. They now have been isolated also from [[soybean]] and the model legume ''[[Medicago truncatula]]''. NFR5 lacks the classical [[activation loop]] in the [[kinase]] domain. The ''NFR5'' gene lacks [[intron]]s. First the cell membrane is depolarized and the root hairs start to swell and cell division stops. Nod factor cause the fragmentation and rearrangement of actin network, which coupled with the reinstitution of cell growth lead to the [[Root hair curling|curling of the root hair]] around the bacteria. This is followed by the localized breakdown of the cell wall and the invagination of the plant cell membrane, allowing the bacterium to form an infection thread. As the infection thread grows the rhizobia travel down its length towards the site of the nodule. During this process the pericycle cells in plants become activated and cells in the inner cortex start growing and become the nodule primordium where the rhizobia infect and differentiate into bacteroids and fix nitrogen. Activation of adjacent middle cortex cells leads to the formation of nodule meristem.<ref name=":0" />