Abbreviations are as follows: GlcN, Glucosamine; GlcNAc, N-acetyl-D-glucosamine; MurNAc, CB-5083 price N-acetylmuramic acid. Farnesyl diphosphate (FPP) biosynthesis It is generally known that rhizobia provide ammonia and other amino acids as a nitrogen source to the host [4], while

no other compound is known to be provided. However, the obtained protein profile suggested that FPP might be provided from rhizobia Repotrectinib datasheet to plant root cells. In the quinone biosynthetic pathway, the enzymes necessary to FPP biosynthesis, such as isopentenyl pyrophosphate isomerase (mlr6371) and geranyltransferase (mlr6368), which are located in the rhizobia symbiosis island, were uniquely detected under the symbiotic condition (Figure 4b). These enzymes produce FPP from isopentenyl diphosphate and dimethyl allyl diphosphate. FPP is an intermediate in the mevalonate pathway, which is present in all higher eukaryotes and many bacteria. FPP is used for the biosynthesis of ubiquinone in SB525334 cell line M. loti. However, the enzymes which catalyze the ubiquinone biosynthesis reactions from FPP (shown in asterisks in Figure 4b) were not detected at the protein level. Additionally, the symbiosis island does not include genes encoding octaprenyl-diphosphate synthase (mlr7426) and 4-hydroxybenzoate polyprenyltransferase (mll7442), which are involved in the pathway of ubiquinone biosynthesis. On the other hand, higher plants utilize FPP as the

G protein-coupled receptor kinase intermediate precursor of many secondary metabolites, such as sesquiterpenes, triterpenes, and sterols [30]. It is reasonable to suppose that FPP is provided to the host legume from rhizobia as a source of secondary metabolites because FPP was synthesized only under the symbiotic condition, as the enzymes that metabolize FPP after its production were not detected in M. loti at the protein level. However, the estimation is just based on the obtained protein profile, and further investigation of the migration of FPP will be carried out by using deletion mutants, and by analysis at mRNA and

metabolite levels. Nucleotide sugar metabolism and peptidoglycan biosynthesis On the other hand, the enzymes involved in uridine diphosphate (UDP) sugar metabolism were not produced under the symbiotic condition (Figure 4c), and LPS transporters (mll3197, mll7564, mll7866) were not produced under the symbiotic condition. UDP-N-acetylglucosamine (UDP-MurNAc) is the starting material for LPS biosynthesis. LPS is known as one of the “nod factors,” which is secreted by the rhizobial body when it perceives the root through the flavonoid groups secreted from host legume [2]. The secretion of LPS is likely unnecessary under the symbiotic condition (after infection). In addition, UDP-N-acetylmuramic acid, the end product of this pathway, is the starting material of peptidoglycan biosynthesis. The enzymes of peptidoglycan biosynthesis were uniquely detected under the free-living condition (Figure 4d).