Nitric oxide production and signalling in algae

Abstract

Nitric Oxide (NO) was the first identified gaseous messenger and is now well established as a major ubiquitous signalling molecule. The rapid enhancement of our understanding of NO biology in embryophytes came with the partial characterization of the pathways underlying its production and with the decrypting of signalling networks mediating its effects. Notably, the identification of proteins regulated by NO through nitrosation greatly enhanced our perception of NO functions. In comparison, the role of NO in algae has been less investigated. Yet, studies in Chlamydomonas reinhardtii have produced key insights into NO production through the identification of NO-forming nitrite reductase and of S-nitrosated proteins. More intriguingly, in contrast to embryophytes few algal species possess a conserved nitric oxide synthase, the main enzyme catalysing NO synthesis in metazoans. This latter finding paves the way for a deeper characterization of unprecedented members of the NOS family. This notwithstanding, the typical NO/cGMP signalling module transducing NO effects in metazoans is not conserved in algae, nor in embryophytes, highlighting a divergent acquisition of the NO signalling between the green and the animal lineages.

Aerobic Bacteria Produce Nitric Oxide via Denitrification and Trigger Algal Population Collapse

“…Our findings expand current knowledge on the role of NO in microbial ecology. Data from the current work and from previous studies demonstrate that NO is a signaling molecule in algae (17,43,47,56,57). We identified noa genes that likely encode NOA enzymes in E. huxleyi, one of which is up-regulated during algal death and potentially facilitates enhanced NO production (Fig.…”

Cross Talk between Hydrogen Peroxide and Nitric Oxide in the Unicellular Green Algae Cell Cycle: How Does It Work?

“…This latter process could involve the interaction of NR with NO-forming nitrite reductase (NOFNiR) [ 20 ]. It was found that NO plays a role in the regulation of various biochemical and physiological processes, including stress responses [ 21 , 22 , 23 ], developmental processes (leaf expansion and root growth), and phytoalexin production [ 24 ]. Furthermore, some data suggest the influence of NO on plant cell division [ 25 ].…”

“…Another possible means of NO signaling are the cyclic nucleotide GMP (cGMP)-mediated pathways. Although this has so far only been described in animal cells [ 23 ]). There are indications that cGMP is also synthesized in plant cells, and this synthesis is enhanced by NO [ 39 ].…”

“…Thus, the ability of cells to complete cell division, through the strict set of parameters and cell signaling, depends on the efficiency of photosynthetic reactions [ 92 ]. During this time, the chloroplast is the main source of ROS, and the photosynthetic activity is an important component of NO generation via NR and NiR pathway [ 23 ]. Thus, the participation of the ROS and RNS in cell cycle progression occurs in the coordination of chloroplast photosynthetic activity and division of this organelle, together with cell division coordination [ 93 ].…”

Identification of Partner Proteins of the Algae Klebsormidium nitens NO Synthases: Toward a Better Understanding of NO Signaling in Eukaryotic Photosynthetic Organisms

“…Several reports have suggested that algae from different lineages, such as chlorophytes, charophytes, red algae, or diatoms, could produce NO ( Mallick et al, 1999 , 2000 ; Sakihama et al, 2002 ; Tischner et al, 2004 ; Chung et al, 2008 ; Vardi et al, 2008 ; Chow et al, 2013 ), and a review of the relevant literature indicates that NO is involved in various functions in algae ( Kumar et al, 2015 ; Astier et al, 2021 ). Briefly, NO contributes to stress responses, particularly to abiotic ones (e.g., hypoxia, wounding, UV or visible light irradiation, chemicals, heat stress, high concentrations of salt, and metal).…”