Bacillus solimangrovi is a Gram-positive bacterium, first isolated from mangrove soil in 2014. As a motile bacterium, it possesses flagella that drives cell locomotion. B. solimangrovi is closely related to the model organism B. subtilis, except that it contains a protective protein coat called a surface-layer (S-layer). As part of its evolutionary adaptation to life in the mangroves, B. solimangrovi possesses 13 additional flagellar genes compared to B. subtilis, that we have named S-layer flagellar (sfl) genes: sflA through to sflM. These genes play different roles in the flagellar system. Some of them encode structural proteins for the flagellar apparatus, but others serve as regulatory genes. For instance, structural genes like sflF and sflI, along with hag, are crucial for the construction of the filament in the flagellum respectively, whereas sflD and sflE genes encode alternative RNA polymerase subunits that control structural gene expression. In this study, by combining genetic engineering and advanced microscopy, we aim to study the structure and function of these uncharacterised proteins in B. solimangrovi.