Cyanobacteria have evolved various strategies to sense and adapt to biotic and abiotic stresses including active movement. Motility in cyanobacteria utilizing the type IV pili (TFP) is useful to cope with changing environmental conditions. The model cyanobacterium Synechocystis sp. PCC 6803 (hereafter named Synechocystis) exhibits motility via TFP called thick pili, and uses it to seek out favorable light/nutrition or escape from unfavorable conditions. Recently, a number of studies on Synechocystis thick pili have been undertaken. Molecular approaches support the role of the pilin in motility, cell adhesion, metal utilization, and natural competence in Synechocystis. This review summarizes the most recent studies on the function of thick pili as well as their formation and regulation in this cyanobacterium.

Monogalactosyldiacylglycerol (MGDG) is the most abundant polar lipid in thylakoid membrane, wherein it plays critical roles related to thylakoid membrane assembly and function in diatoms. However, diatom MGDG biosynthesis has not been fully characterized. In this study, we investigated the role of a novel MGDG synthase (ptMGD2), which is one of the key enzymes for MGDG biosynthesis, in the model diatom Phaeodactylum tricornutum. An analysis of subcellular localization demonstrated that the ptMGD2 is mainly localized in plastids. Gene disruption by gene editing of ptMGD2 resulted in delayed growth, decrease in oxygen evolution rate, reduced MGDG and digalactosyldiacylglycerol (using MGDG as the substrate) content as well as lipid remodeling. Considered together, these observations provide novel insights into the importance of ptMGD2 for regulating MGDG biosynthesis and its potential roles in biotechnical application of Phaeodactylum.