Putative porin of Bradyrhizobium sp. (Lupinus) bacteroids induced by glyphosate.
Application of glyphosate (N-[phosphonomethyl] glycine) to Bradyrhizobium sp. (Lupinus)-nodulated lupin plants caused modifications in the protein pattern of bacteroids. The most significant change was the presence of a 44-kDa polypeptide in bacteroids from plants treated with the higher doses of glyphosate employed (5 and 10 mM). The polypeptide has been characterized by the amino acid sequencing of its N terminus and the isolation and nucleic acid sequencing of its encoding gene. It is putatively encoded by a single gene, and the protein has been identified as a putative porin. Protein modeling revealed the existence of several domains sharing similarity to different porins, such as a transmembrane beta-barrel. The protein has been designated BLpp, for Bradyrhizobium sp. (Lupinus) putative porin, and would be the first porin described in Bradyrhizobium sp. (Lupinus). In addition, a putative conserved domain of porins has been identified which consists of 87 amino acids, located in the BLpp sequence 30 amino acids downstream of the N-terminal region. In bacteroids, mRNA of the BLpp gene shows a basal constitutive expression that increases under glyphosate treatment, and the expression of the gene is seemingly regulated at the transcriptional level. By contrast, in free-living bacteria glyphosate treatment leads to an inhibition of BLpp mRNA accumulation, indicating a different effect of glyphosate on BLpp gene expression in bacteroids and free-living bacteria. The possible role of BLpp in a metabolite interchange between Bradyrhizobium and lupin is discussed.
de María
Nuria
N
Instituto de Recursos Naturales, Centro de Ciencias Medioambientales, CSIC, Serrano, 115-bis, E-28006 Madrid, Spain.
Guevara
Angeles
A
Serra
M Teresa
MT
García-Luque
Isabel
I
González-Sama
Alfonso
A
García de Lacoba
Mario
M
de Felipe
M Rosario
MR
Fernández-Pascual
Mercedes
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D015139:Blotting, Southern; D020369:Bradyrhizobium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D018272:Porins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein; D000097797:Glyphosate
D001426:Bacterial Proteins; D005998:Glycine; D018272:Porins; D012333:RNA, Messenger; D000097797:Glyphosate