Open AccessSinorhizobium meliloti genes involved in tolerance to the antimicrobial peptide protamine
Author(s) -
Nogales Joaquina,
Muñoz Socorro,
Olivares José,
Sanjuán Juan
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00445.x
Subject(s) - sinorhizobium meliloti , biology , mutant , protamine , transposable element , microbiology and biotechnology , antimicrobial , gene , antimicrobial peptides , beta defensin , biochemistry , peptide , genetics , heparin
The innate resistance of plants and animals to microbial infection is mediated in part by small cationic peptides with antimicrobial activity. We assessed the susceptibility of the alfalfa symbiont Sinorhizobium meliloti to the model antimicrobial peptide protamine. Twenty‐one Tn 5 ‐induced mutants showing increased sensitivity to protamine were isolated, and nine were further characterized in detail. These nine mutants carried distinct transposon insertions that affected a total of seven different genes. Three of these genes are involved in exopolysaccharide and β‐(1,2)‐glucan biosynthesis ( exoT , exoU and ndvB ), three other genes are implicated in nitrogen metabolism, such as a putative dyhidropyrimidinase, hutU and ureF , and the last gene exhibited similarity to the ATP binding cassette family of membrane transporters. Symbiotic defects ranging from severe to moderate were displayed by some of the protamine‐hypersensitive mutants suggesting that S. meliloti possess active mechanisms to counteract hypothetical cationic peptides that may be produced by its host plant.