Polyamines in Microalgae: Something Borrowed, Something New

Abstract

Microalgae of different evolutionary origins are typically found in rivers, lakes, and oceans, providing more than 45% of global primary production. They provide not only a food source for animals, but also affect microbial ecosystems through symbioses with microorganisms or secretion of some metabolites. Derived from amino acids, polyamines are present in almost all types of organisms, where they play important roles in maintaining physiological functions or against stress. Microalgae can produce a variety of distinct polyamines, and the polyamine content is important to meet the physiological needs of microalgae and may also affect other species in the environment. In addition, some polyamines produced by microalgae have medical or nanotechnological applications. Previous studies on several types of microalgae have indicated that the putative polyamine metabolic pathways may be as complicated as the genomes of these organisms, which contain genes originating from plants, animals, and even bacteria. There are also several novel polyamine synthetic routes in microalgae. Understanding the nature of polyamines in microalgae will not only improve our knowledge of microalgal physiology and ecological function, but also provide valuable information for biotechnological applications.

Phytoplankton pangenome reveals extensive prokaryotic horizontal gene transfer of diverse functions

“…S2D). Polyamine is involved in stress re-sponse and cell division control, thereby promoting growth (16). The transfer of these two related gene functions was likely associated with the adaptation of F. cylindrus to cold polar waters.…”

Plant Biostimulants from Cyanobacteria: An Emerging Strategy to Improve Yields and Sustainability in Agriculture

“…Phytohormones such as cytokinins, betaines, and gibberellins in cyanobacterial extracts may play a role in reducing chlorophyll degradation mainly through inhibition of chlorophyllase activity [ 115 , 116 ]. Among substances with hormone-like activity, exogenously applied polyamines can be covalently conjugated to chlorophyll-bound proteins by plastidial transglutaminases, thus improving chlorophyll stability during leaf senescence [ 117 ]. These findings suggest a role for cyanobacterial applications in mitigating the negative effects of abiotic stresses on crops.…”

Enhancing Sustainability by Improving Plant Salt Tolerance through Macro- and Micro-Algal Biostimulants

“…Considerable amounts of polyamines, in particular putrescine and spermidine, were also found in unicellular and multicellular green and red algae (Chlorophyta, Charophyta, and Rhodophyta) [ 85 , 86 ]. Polyamines, aliphatic compounds deriving from two or more amino acids, play multiple roles—for instance, in the regulation of the cell cycle, and in sugar and lipid homeostasis.…”

“…Polyamines, aliphatic compounds deriving from two or more amino acids, play multiple roles—for instance, in the regulation of the cell cycle, and in sugar and lipid homeostasis. Polyamines are also important in plants for their antioxidant capacity and role in osmotic regulation both as osmoprotectants and signaling molecules [ 86 ]. Trehalose, a non-reducing disaccharide that act also as an osmolyte, carbon reserve, and stress protectant [ 87 ], is accumulated in algae such as Chlamydomonas , Chlorella, and Scytonema under salinity [ 88 ].…”