An Ocean of Signals: Intracellular and Extracellular Signaling in Diatoms

Creveld, Shiri Graff van; Mizrachi, Avia; Vardi, Assaf

doi:10.1007/978-3-030-92499-7_22

Cited by 4 publications

(3 citation statements)

References 219 publications

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“…There are several examples of chemically mediated communication in unicellular organisms ( [40]), with some of them having a critical role in dormancy ( [41]). In diatoms, the most studied infochemicals related to intra-and inter-specific communication are compounds belonging to the oxylipin family [42], which include polyunsaturated aldehydes (PUAs) and linear oxygenated fatty acids (LOFAs), both derived from the oxygenation of fatty acids ( [43]). The first step of their synthesis derives from the oxidation of membrane lipids, through several enzymes among which a crucial role is played by lipoxygenases.…”

Section: Chemical Signaling Pathways Related To Oxylipin Productionmentioning

confidence: 99%

Gene expression during the formation of resting spores induced by nitrogen starvation in the marine diatom Chaetoceros socialis

Pelusi¹,

Ambrosino²,

Miralto³

et al. 2023

BMC Genomics

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Background Dormancy is widespread in both multicellular and unicellular organisms. Among diatoms, unicellular microalgae at the base of all aquatic food webs, several species produce dormant cells (spores or resting cells) that can withstand long periods of adverse environmental conditions. Results We present the first gene expression study during the process of spore formation induced by nitrogen depletion in the marine planktonic diatom Chaetoceros socialis. In this condition, genes related to photosynthesis and nitrate assimilation, including high-affinity nitrate transporters (NTRs), were downregulated. While the former result is a common reaction among diatoms under nitrogen stress, the latter seems to be exclusive of the spore-former C. socialis. The upregulation of catabolic pathways, such as tricarboxylic acid cycle, glyoxylate cycle and fatty acid beta-oxidation, suggests that this diatom could use lipids as a source of energy during the process of spore formation. Furthermore, the upregulation of a lipoxygenase and several aldehyde dehydrogenases (ALDHs) advocates the presence of oxylipin-mediated signaling, while the upregulation of genes involved in dormancy-related pathways conserved in other organisms (e.g. serine/threonine-protein kinases TOR and its inhibitor GATOR) provides interesting avenues for future explorations. Conclusions Our results demonstrate that the transition from an active growth phase to a resting one is characterized by marked metabolic changes and provides evidence for the presence of signaling pathways related to intercellular communication.

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Section: Chemical Signaling Pathways Related To Oxylipin Productionmentioning

confidence: 99%

Gene expression during the formation of resting spores induced by nitrogen starvation in the marine diatom Chaetoceros socialis

Pelusi¹,

Ambrosino²,

Miralto³

et al. 2023

BMC Genomics

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“…In algae, there is accumulating evidence for PCD characteristics in response to various stressors, such as nutrient limitation, heat stress, pathogens, high light, various infochemicals and oxidative stress [12][13][14][15][16][17][18][19][20] . Reactive oxygen species (ROS) were shown to play an important role in stress sensing and mediating PCD in algae and across the kingdoms of life [21][22][23][24] . In the diatom Phaeodactylum tricornutum, H2O2 treatment leads to cell mortality with characteristics of PCD, including externalization of phosphatidylserine, DNA laddering, and compromised cell membranes 16 .…”

Section: Introductionmentioning

confidence: 99%

Cathepsin X is a conserved cell death protein involved in algal response to environmental stress

Mizrachi,

Sadeh,

Ben-Dor

et al. 2024

Preprint

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Phytoplankton play a crucial role in global primary production and can form vast blooms in aquatic ecosystems. Bloom demise and the rapid turnover of phytoplankton are suggested to involve programmed cell death (PCD) induced by diverse environmental stressors. However, fundamental knowledge of the PCD molecular components in algae and protists in general remains elusive. Previously, we revealed that early oxidation in the chloroplast predicted subsequent cell death or survival in isogenic subpopulations that emerged following H2O2 treatment in the diatom Phaeodactylum tricornutum. Here, we performed transcriptome analysis of sorted sensitive oxidized cells and resilient reduced cells, to discover genes linked to their contrasting fates. By cross-comparison with a large-scale mutant screen in the green alga Chlamydomonas reinhardtii, we identified functionally relevant conserved PCD gene candidates, including the cysteine protease cathepsin X/Z (CPX). CPX mutants in P. tricornutum CPX1 and C. reinhardtii CEP12 both exhibited profound resilience to oxidative stress, supporting a conserved function in algal PCD. P. tricornutum cpx1 mutants, generated using CRISPR-Cas9, also exhibited resilience to the toxic diatom-derived infochemical cyanogen bromide. Phylogenetic and predictive structural analyses show that CPX is highly conserved in eukaryotes, and algae of the green and red lineages exhibit strong structural similarity to human cathepsin CTSZ. CPX is expressed by diverse algae across the oceans and during toxic Pseudo-nitzschia blooms, supporting its ecological importance. Elucidating PCD components in algae sheds light on the evolutionary origin of PCD in unicellular organisms, and on the cellular strategies employed by the population to cope with stressful conditions.

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“…Néanmoins, les mécanismes épigénétiques, ainsi que les réseaux métaboliques ou de signalisation cellulaire contribuent également aux interactions algues-environnement. Cela a été bien étudié chez les plantes terrestres [14], mais n'a encore été abordé que sur un faible nombre d'espèces de microalgues [9,13,15,16,55].…”

Section: Introductionunclassified

Light-driven processes: key players of the functional biodiversity in microalgae

Falciatore¹,

Bailleul²,

Boulouis³

et al. 2022

Comptes Rendus. Biologies

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Microalgae are prominent aquatic organisms, responsible for about half of the photosynthetic activity on Earth. Over the past two decades, breakthroughs in genomics and ecosystem biology, as well as the development of genetic resources in model species, have redrawn the boundaries of our knowledge on the relevance of these microbes in global ecosystems. However, considering their vast biodiversity and complex evolutionary history, our comprehension of algal biology remains limited. As algae rely on light, both as their main source of energy and for information about their environment, we focus here on photosynthesis, photoperception, and chloroplast biogenesis in the green alga Chlamydomonas reinhardtii and marine diatoms. We describe how the studies of lightdriven processes are key to assessing functional biodiversity in evolutionary distant microalgae. We also emphasize that integration of laboratory and environmental studies, and dialogues between different scientific communities are both timely and essential to understand the life of phototrophs in complex ecosystems and to properly assess the consequences of environmental changes on aquatic environments globally.

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An Ocean of Signals: Intracellular and Extracellular Signaling in Diatoms

Cited by 4 publications

References 219 publications

Gene expression during the formation of resting spores induced by nitrogen starvation in the marine diatom Chaetoceros socialis

Gene expression during the formation of resting spores induced by nitrogen starvation in the marine diatom Chaetoceros socialis

Cathepsin X is a conserved cell death protein involved in algal response to environmental stress

Light-driven processes: key players of the functional biodiversity in microalgae

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