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Sulphation of Rhizobium sp. NGR234 Nod factors is dependent on noeE , a new host‐specificity gene
Author(s) -
Hanin M.,
Jabbouri S.,
QuesadaVincens D.,
Freiberg C.,
Perret X.,
Promé J.C.,
Broughton W. J.,
Fellay R.
Publication year - 1997
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1997.3981777.x
Subject(s) - biology , rhizobium , plasmid , fucose , nod , gene , sulfation , rhizobia , nod factor , biochemistry , acetylation , symbiosis , bacteria , genetics , galactose
Rhizobia secrete specific lipo‐chitooligosaccharide signals (LCOs) called Nod factors that are required for infection and nodulation of legumes. In Rhizobium sp. NGR234, the reducing N ‐acetyl‐ d ‐glucosamine of LCOs is substituted at C 6 with 2‐ O ‐methyl‐ l ‐fucose which can be acetylated or sulphated. We identified a flavonoid‐inducible locus on the symbiotic plasmid pNGR234 a that contains a new nodulation gene, noeE which is required for the sulphation of NGR234 Nod factors (NodNGR). noeE was identified by conjugation into the closely related Rhizobium fredii strain USDA257, which produces fucosylated but non‐sulphated Nod factors (NodUSDA). R. fredii transconjugants producing sulphated LCOs acquire the capacity to nodulate Calopogonium caeruleum . Furthermore, mutation of noeE (NGRΔ noeE ) abolishes the production of sulphated LCOs and prevents nodulation of Pachyrhizus tuberosus . The sulphotransferase activity linked to NoeE is specific for fucose. In contrast, the sulphotransferase NodH of Rhizobium meliloti seems to be less specific than NoeE, because its introduction into NGRΔ noeE leads to the production of a mixture of LCOs that are sulphated on C 6 of the reducing terminus and sulphated on the 2‐ O ‐methylfucose residue. Together, these findings show that noeE is a host‐specificity gene which probably encodes a fucose‐specific sulphotransferase.