Comparative study of the pln locus of Lactobacillus plantarum
Navarro, L., Rojo-Bezares, B., Sáenz, Y., Díez, L., Zarazaga, M., RuizLarrea, F., and Torres, C.
Department of Food and Agriculture, University of La Rioja, Av Madre de Dios 51.
26006 Logroño, Spain.
Phone number +34 941299750. e-mail: carmen.torres@unirioja.es
A previous study of our group1 had shown that Lactobacillus plantarum J51, isolated
from a red wine, was a plantaricin producer able to inhibit the growth of a number of
lactic acid bacteria species. In the present study we show the full sequence of the pln
locus, responsible for the production and regulation of plantaricins, of our J51 strain. A
20,667 bp fragment was amplified by PCR and primer-walking strategy, and fully
sequenced. Comparison of sequences with previously characterised pln locus of other
plantaricin producers (L. plantarum C11: GenBank no. X94434; L. plantarum NC8:
AF522077; L. plantarum J23: DQ323671) rendered a very interesting genetic map that
contained: the regulatory plnABCD operon previously described for L. plantarum C11,
two operons that encode plantaricin and immunity proteins and two other operons
related to plantaricin biosynthesis and secretion, that had been described for C11, NC8
and J23 strains. The pln locus of J51 showed a new combination of these previously
described five operons, and additionally it showed a characteristic promoter sequence
followed by three novel orfs encoding two putative peptides that contain the
characteristic double glycine motive of class IIb bacteriocins, and a putative immunity
protein. The comparative study of the four pln locus and the corresponding mechanisms
of plantaricin production regulation, reinforce the hypothesis of high plasticity in
localized genetic regions of L. plantarum that are involved in adaptation and
competition with other bacteria.
1
Navarro, L. et al. 2000. J. Appl. Microbiol. 88: 44-51.