Entry 5
Probiotic science page
Reference genome strain used to define L. plantarum genetics and host interaction mechanisms, with no direct human clinical evidence.

Overview
WCFS1 is the reference strain for L. plantarum research. It was isolated from human saliva. It was the first Lactobacillus to have its full genome sequenced [1]. WCFS1 is mainly a research tool, not a commercial probiotic. Scientists use it as a base for studying lactobacillus genes [7].
Mechanism
The full genome is 3.3 Mb. It has 3,052 predicted protein-coding genes. Many of these are sugar transport and use systems. This shows the strain can use many kinds of sugars [1]. WCFS1 has the plantaricin gene cluster. Plantaricin is a bacteriocin (a bacteria-killing compound) [1]. The strain carries three prophages. These are viral DNA left in the genome by past infections. They add to genome flexibility [1]. Researchers used WCFS1 to map the control networks for stress response, quorum sensing, and biofilm formation [1].
Health Benefits
WCFS1 is mostly a reference strain. Human RCT data are absent. It has been used a lot in lab tests. These tests define how L. plantarum sticks to cells lining the gut, tunes the immune system, and metabolizes nutrients [1]. Evidence level: in vitro (genomics, mechanism). No direct human clinical evidence.
Biology
Originally named Lactobacillus plantarum. It was reclassified as Lactiplantibacillus plantarum in 2020 [2]. It is Gram-positive. It grows with or without oxygen. It does not form spores. It is a rod. It produces lactic acid plus other byproducts. The lactic acid is D- and L-form. It was isolated from human saliva. Genome size is about 3.3 Mb. GC content is about 44.5%. It has three plasmids [1].
Bibliography
Kleerebezem M, Boekhorst J, van Kranenburg R, et al. (2003). Complete genome sequence of Lactobacillus plantarum WCFS1. Proc Natl Acad Sci U S A. 100(4):1990-1995. PMID: 12566566
Zheng J, Wittouck S, Salvetti E, et al. (2020). A taxonomic note on the genus Lactobacillus… Int J Syst Evol Microbiol. 70(4):2782-2858. PMID: 32293557
Leimena MM, Wels M, Bongers RS, et al. (2012). “Comparative analysis of Lactobacillus plantarum WCFS1 transcriptomes by using DNA microarray and next-generation sequencing technologies.” Appl Environ Microbiol. 78(12):4234-4242. PMID: 22492454
Available Products
No commercial probiotic products contain WCFS1. It is available from the Wageningen UR culture collection and academic repositories as a research reference.