Review of phenotypic response of diatoms to salinization with biotechnological relevance

Abstract

AbstractSalinization is one of the main global environmental issues of the Anthropocene with various consequences for aquatic ecosystems. To understand diatom ecology and evolution from this perspective without knowing the impact of salinity on their physiological and molecular mechanisms is unimaginable. For this reason, we collected the existing knowledge about the intracellular and morphological changes of diatoms induced by salinity. The available studies revealed that salt stress can significantly affect, among others, their photosynthetic activities, pigment contents, growth rate, metabolism, and toxin synthesis. Acclimation capability of diatoms is apparent: they can adjust turgor pressure and ion homeostasis and produce compatible solutes for osmoprotection applying a number of biochemical pathways and complementary mechanisms. Morphological changes like shape resistance, post-auxospore formation, and several micro- and nano-sized sometimes species-specific variations can also be explained by the increasing salinity. Furthermore, abnormal forms indicate the extreme and complex effect of salinity and collateral stress factors. Their salinity tolerance threshold is species specific, which can be exploited by biotechnology. According to studies collected for this review, it is obvious that diatoms have various phenotypic responses to salinity; however, knowledge about their molecular background and long-term adaptation of the species are completely missing.