The presence of prtP proteinase gene in natural isolate Lactobacillus plantarum BGSJ3–18

Aims:  The study of proteolytic activity and examination of proteinase gene region organization in proteolytically active Lactobacillus plantarum strains from different natural sources.
Methods and Results:  A set of 37 lactobacilli was distinguished by using multiplex PCR assay. Results showed that 34 strains were Lact. plantarum and three of them were Lact. paraplantarum . The examination of proteolytic activity revealed that 28 Lact.   plantarum and two Lact.   paraplantarum hydrolyse β-casein. Further analyses of all proteolytically active Lact. plantarum with primers specific for different types of CEPs demonstrated that strain BGSJ3–18 has prtP catalytic domain as well as prtP – prtM intergenic region showing more than 95% sequence identity with the same regions present in Lact. paracasei , Lact. casei and L. lactis . No presence of prtB , prtH or prtR proteinase genes was detected in any of tested Lact. plantarum strains.
Conclusions:  One out of 28 analysed Lact. plantarum strains harbours the prtP -like gene. The other proteolytically active Lact. plantarum probably possesses a different type of extracellular proteinase(s).
Significance and Impact of the Study:  It is the first report about the presence of the prtP –like gene in Lact. plantarum , which illustrates the mobility of this gene and its presence in different species.