Mìkrobìologìâ ì Bìotehnologìâ (Mar 2014)
EFFECT OF LACTOBACILLUS PLANTARUM ON TUMOR FORMATION CAUSED BY RHIZOBIUM RADIOBACTER
Abstract
The aim of investigation was to study the effect of Lactobacillus plantarum bacteria and their metabolites on tumor formation in Kalanchoe daigremontiana Mill. plants experimentally inoculated with crown gall agents Rhizobium radiobacter. Methods. Leaves of test plants were inoculated with the cultures of bacteria R. radiobacter С58 and three Lactobacillus plantarum strains or their cell-free supernatants (CFS) with primary low pH (4.1–4.3) and with neutralized pH (6.5) in a ratio 1:1. After 45 days amount of samples with tumors and weight of tumor tissues were evaluated, and formation of necroses were checked out. Results. Lactobacilli and their supernatants effected tumor formation differently depending on the variant of treatment. Inhibiting activity in a case of all three investigated L. plantarum strains was exhibited by CFS with primary pH (4.1–4.3). Lactobacilli injected in plant tissues simultaneously with the pathogen decreased the amount of crown galled samples both in a case of low initial pH of cultural liquid (strain L. plantarum ONU 87 decreased in 86%, strain L. plantarum ONU 206 – in 95%), and in a case of neutralized pH of cultural liquid (strain L. plantarum ONU 87 decreased in 75%, strain L. plantarum ONU 206 – decreased in 94%). Bacteria of the strain L. plantarum ONU 991 didn’t exhibit the inhibiting activity in cases of the treatments with cultures of lactobacilli and with the neutralized supernatant. At the same time, the overnight cultures of all strains showed clear antagonistic activity in vitro. Injecting the cultures of lactobacilli and their supernatants both with low and neutral pH resulted in wide zones of necrosis comparing to that obtained after the injection of tissues with sterile distillated water with the same pH. Conclusion. Lactic acid bacteria L. plantarum differ in the level of inhibition of tumor formation caused by R. radiobacter. Strain L. plantarum 206 was the best antagonist in these investigations: both the amount of infected samples and weight of formed tumors significantly decreased in all variants of the treatments. Inhibiting activity of metabolites from the cultural liquid of lactobacteria probably is explained not only with the action of organic acids, but also with the action of bacteriocins and other products of metabolism.
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