Root‐nodule Symbiosis: Molecular Basis of Nodule Formation

Abstract

Nutrient availability is a major limitation to plant growth. Legumes have entered into a symbiotic interaction with nitrogen‐fixing rhizobial bacteria that provide the plant with a source of nitrogen. The legume/rhizobial symbiosis is globally important for introducing nitrogen into biological systems. Legume crops are used in sustainable agricultural processes to naturally enrich the soil for nitrogen. Our understanding of the molecular mechanisms that underlie this interaction is expanding and we are beginning to understand the means by which the molecular dialogue occurs between the plant and the bacteria. The signalling pathway in the plant, that is responsible for the recognition of the bacterial signal Nod factor, appears to have evolved in part from a pre‐existing signalling pathway necessary for the establishment of the mycorrhizal symbiosis. Further research in this field may help to apply this symbiosis more broadly in agriculture.

Two shifts in evolutionary lability underlie independent gains and losses of root-nodule symbiosis in a single clade of plants

“…The primary mechanism of C4 gene evolution by gene duplication, non-functionalization, and neofunctionalization 43 established the importance of duplicating preexisting genetic material in generating remarkable trait lability. Despite intensive work to understand the underlying mechanisms of RNS in model legume species, with important results [44][45][46][47] , little is known about how RNS is lost and gained, although polyploidy may have played a role, at least in the case of papilionoid legume nodules 48,49 . Even less is known about the mechanisms controlling RNS outside of legumes.…”

“…The copyright holder for this preprint this version posted August 1, 2022. ; https://doi.org/10.1101/2022.07.31.502231 doi: bioRxiv preprint generating remarkable trait lability. Despite intensive work to understand the underlying mechanisms of RNS in model legume species, with important results [44][45][46][47] , little is known about how RNS is lost and gained, although polyploidy may have played a role, at least in the case of papilionoid legume nodules 48,49 . Even less is known about the mechanisms controlling RNS outside of legumes.…”

Új Medicago truncatula szimbiotikus gének azonosítása és jellemzése és az NSP2 gén két pontmutáns alléljának funkcionális analízise

“…Az NF az első szignálmolekula, amelyet a gazdanövény érzékel különböző receptorai segítségével (2.1. ábra /B) és ez az a jelmolekula, amely beindítja a növényben azokat a változásokat, amelyek alkalmassá teszik a baktérium partner fogadására. Az NF egy rendkívül hatásos szignálmolekula, már 1 pM koncentrációban is képes specifikus növényi válaszreakciók kiváltására (Oldroyd, 2007). A szimbiózis kialakulásának későbbi szakaszában, a növény-baktérium közötti kommunikáció következő szintjét a baktérium felszínén lévő különböző összetételű felszíni poliszacharidok jelentik, melyeket ugyancsak különböző receptorok segítségével érzékel a növény (2.1. ábra /C).…”