Spontaneous and SDS-induced Phenotype and Plasmid Alterations in Starter Cultures of Lactobacillus plantarum

Abstract

Summary Starter cultures of Lactobacillus plantarum, unable to grow beyond a micro-colony stage on nutritionallydeficient media, spontaneously adapt by forming macro-colony variants after 5–14 days of incubation. Twenty-eight percent of the variants remained stable; some of them with altered ability to utilize various carbohydrates. Eighteen percent of the stable variants showed plasmid changes, but there was no obvious participation of plasmids in the variant formation. Restriction endonuclease analysis indicated that DNA rearrangement had occurred in the variant strain studied. SDS-treatment resulted in approximately half of the population reverting to the micro-colony phenotype. Depending on the cultivation media, high-frequency-spontaneous-mutation (HFSM) in Lactobacillus plantarum showed frequencies up to 10-5 mutants per cells inoculated on a plate.