BIOFILM FORMATION AND GENETIC DIVERSITY OF LACTOBACILLUS PLANTARUM STRAINS ORIGINATED FROM FRANCE AND UKRAINE

Abstract

Evaluation of Lactobacillus plantarum strains perspective for plant protection or fermentation of food of plant origin should include tests on abilities to attach to plant surfaces and to form biofilms. Comparing RAPD-profiles with these properties and also with geographical origin of the strains is necessary to find out the possibility of rapid selection of the strains and tracking their dissemination. Biofilm formation and RAPD-PCR profiles of 30 strains of L. plantarum isolated from grape must and pickles originated from France and Ukraine were compared. All isolates were able to attach to Lepidium sativum seedlings and form biofilms of different types. Amount of attached cells varied from (7.8 ± 0.2) x 104 to (2.1 ± 0.3) x 103 CFU/cm2. The most developed biofilms were formed on shoots, leaves, seed coat shells. On roots this ability was strain dependent: the majority of French isolates (77.0%) formed separated microcolonies without developed matrix layer. Among Ukrainian isolates, 47.1% of the strains showed the same tendency, and in 41.2% of the strains individual attached cells without formation of microcolonies were observed. The level of initial attachment of bacterial cells to roots did not coincide with the level of subsequent formation of biofilms. Gene plnA was detected in 28.1% of isolates. All plnA possessing strains except the one formed microcolonies or biofilms with developed matrix. Lactobacilli could eliminate the biofilms of Agrobacterium tumefaciens pJZ from tomato roots in 75.0 – 100% of tested samples depending on a strain and method of inoculation. No clear association between the geographical origin of the L. plantarum strains and clustering by RAPD-PCR analysis was found. Two strains with high level of biofilm formation were grouped in one subcluster.