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Role of nodl and nodj in lipo‐chitooligosaccharide secretion in Azorhizobium caulinodans and Escherichia coli
Author(s) -
FernándezLópez Manuel,
D'Haeze Wim,
Mergaert Peter,
Verplancke Christa,
Prome JeanClaude,
Montagu Marc,
Holsters Marcelle
Publication year - 1996
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 - 10.1111/j.1365-2958.1996.tb02540.x
Subject(s) - biology , complementation , mutant , escherichia coli , secretion , microbiology and biotechnology , rhizobia , nod , plasmid , strain (injury) , gene , nod factor , bacteria , symbiosis , biochemistry , genetics , anatomy
Summary Lipo‐chitooligosaccharide (LCO) Nod factors are produced and secreted by rhizobia and trigger nodule development in leguminous host plants. The products of the bacterial nodlJ genes are related to transporters of capsular polysaccharides and were proposed to be involved in LCO transport. We have studied nodlJ of Azorhizobium caulinodans ORS571 by analysis of cell‐associated and secreted radioactively labelled Nod factors in wild‐type ORS571, a nodJ mutant and a complemented strain. Secretion was strongly reduced in the nodJ mutant, and restored to wild‐type levels after complementation. Constructs were made for expression of combinations of different nod genes in Escherichia coli DH5a. The strain DH5α(pUCNABCSU) synthesized LCOs, but they were only secreted when a plasmid containing both nodl and nodJ was supplied in trans, nodi or nodJ alone was not sufficient. In E . coli as well as in Azorhizobium , the nod/J‐encoded transporter showed a specificity for more hydrophilic LCOs.