Farnesol and geranylgeraniol in plant reproduction: insights from Arabidopsis and beyond

Isoprenoids (also called terpenoids) are a large group of natural chemical compounds. Some isoprenoids are specialized metabolites that give smell and taste to plants and provide protection against herbivores and pathogens. Production of these particular substances is specific to certain species and plant families, and is classified as secondary metabolism. In addition, numerous isoprenoids perform essential cellular functions: for example, chloroplast isoprenoids give rise to photosynthetic pigments, electron transporters, and membrane modifiers in the thylakoid membrane to adjust the correct level of photosynthetic performance and prevent oxidative damage in the chloroplasts. Similarly, some cytoplasmic isoprenoids serve a key role in the primary cell metabolism of all eukaryotic cells, forming membrane microdomains (sterols), serving as lipid anchors for prenylated proteins (geranylgeranyl and farnesyl groups), and as co-factors of protein glycosylation (dolichols). The non-steroid isoprenoids (prenyl groups of proteins and ubiquinone, dolichols) and their role in the plants are far less described than sterols. In this review, we present a summary of the knowledge on protein prenylation, but also farnesol and geranylgeraniol turnover in the cytoplasm in the context of membrane structure, biochemistry, plant physiology, and development in Arabidopsis and other plant species.