Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

BacA is an integral membrane protein, the mutation of which leads to increased resistance to the antimicrobial peptides bleomycin and Bac7(1-35) and a greater sensitivity to SDS and vancomycin in Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli, and Rhizobium etli. The growth of Rhizobium strains on dicarboxylates as a sole carbon source was impaired in bacA mutants but was overcome by elevating the calcium level. While bacA mutants elicited indeterminate nodule formation on peas, which belong to the galegoid tribe of legumes, bacteria lysed after release from infection threads and mature bacteroids were not formed. Microarray analysis revealed almost no change in a bacA mutant of R. leguminosarum bv. viciae in free-living culture. In contrast, 45 genes were more-than 3-fold upregulated in a bacA mutant isolated from pea nodules. Almost half of these genes code for cell membrane components, suggesting that BacA is crucial to alterations that occur in the cell envelope during bacteroid development. In stark contrast, bacA mutants of R. leguminosarum bv. phaseoli and R. etli elicited the formation of normal determinate nodules on their bean host, which belongs to the phaseoloid tribe of legumes. Bacteroids from these nodules were indistinguishable from the wild type in morphology and nitrogen fixation. Thus, while bacA mutants of bacteria that infect galegoid or phaseoloid legumes have similar phenotypes in free-living culture, BacA is essential only for bacteroid development in indeterminate galegoid nodules.

Original publication




Journal article


J Bacteriol

Publication Date





2920 - 2928


Bacterial Proteins, Fabaceae, Gene Expression Regulation, Bacterial, Microbial Sensitivity Tests, Oligonucleotide Array Sequence Analysis, Peas, Rhizobium leguminosarum