contribution of nfp lysm domains to the recognition of nod factors during the medicago truncatulasinorhizobium meliloti symbiosis临界多边形求解的贡献lysm域点头因素的识别在medicago truncatulasinorhizobium meliloti共生关系.pdf

Contribution of NFP LysM Domains to the Recognition of Nod Factors during the Medicago truncatula/ Sinorhizobium meliloti Symbiosis Sandra Bensmihen1,2*, Franc¸oise de Billy1,2, Clare Gough1,2 1 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Institut National de la Recherche Agronomique, Castanet-Tolosan, France, 2 Laboratoire des Interactions Plantes-Microorganismes (LIPM), Centre National de la Recherche Scientifique, Castanet-Tolosan, France Abstract The root nodule nitrogen fixing symbiosis between legume plants and soil bacteria called rhizobia is of great agronomical and ecological interest since it provides the plant with fixed atmospheric nitrogen. The establishment of this symbiosis is mediated by the recognition by the host plant of lipo-chitooligosaccharides called Nod Factors (NFs), produced by the rhizobia. This recognition is highly specific, as precise NF structures are required depending on the host plant. Here, we study the importance of different LysM domains of a LysM-Receptor Like Kinase (LysM-RLK) from Medicago truncatula called Nod factor perception (NFP) in the recognition of different substitutions of NFs produced by its symbiont Sinorhizobium meliloti. These substitutions are a sulphate group at the reducing end, which is essential for host specificity, and a specific acyl chain at the non-reducing end, that is critical for the infection process. The NFP extracellular domain (ECD) contains 3 LysM domains that are predicted to bind NFs. By swapping the whole ECD or individual LysM domains of NFP for those of its orthologous gene from pea, SYM10 (a legume plant that interacts with another strain of rhizobium producing NFs with different substitutions), we showed that NFP is not directly responsible for specific recognition of the sulphate substitution of S. meliloti NFs, but probably interacts with the acyl sub