Analysis of the Proteome of the Marine Diatom Phaeodactylum tricornutum Exposed to Aluminum Providing Insights into Aluminum Toxicity Mechanisms

Abstract

Trace aluminum (Al) concentrations can be toxic to marine phytoplankton, the basis of the marine food web, but the fundamental Al toxicity and detoxification mechanisms at the molecular levels are poorly understood. Using an array of proteomic, transcriptomic, and biochemical techniques, we describe in detail the cellular response of the model marine diatom Phaeodactylum tricornutum to a short-term sublethal Al stress (4 h of exposure to 200 μM total initial Al). A total of 2204 proteins were identified and quantified by isobaric tags for relative and absolute quantification (iTRAQ) in response to the Al stress. Among them, 87 and 78 proteins performing various cell functions were up- and down-regulated after Al treatment, respectively. We found that photosynthesis was a key Al toxicity target. The Al-induced decrease in electron transport rates in thylakoid membranes lead to an increase in reactive oxygen species (ROS) production, which cause increased lipid peroxidation. Several ROS-detoxifying proteins were induced to help decrease Al-induced oxidative stress. In parallel, glycolysis and pentose phosphate pathway were up-regulated in order to produce cell energy (NADPH, ATP) and carbon skeleton for cell growth, partially circumventing the Al-induced toxicity effects on photosynthesis. These cellular responses to Al stress were coordinated by the activation of various signal transduction pathways. The identification of Al-responsive proteins in the model marine phytoplankton P. tricornutum provides new insights on Al stress responses as well as a good start for further exploring Al detoxification mechanisms.

Global transcriptomic response ofAnoxybacillussp. SK 3-4 to aluminum exposure

“…Apart from that, when the marine diatom Phaeodactylum tricornutum exposed to aluminum, the abundance of enzyme associated with glycolysis were also found to be up‐regulated. The results suggested that increasing in ATP production is crucial for energy metabolism in the eukaryotic system during aluminum exposure . Interestingly, the gene ldh ( l ‐lactate dehydrogenase) which convert pyruvate into lactate is found to be up‐regulated under aluminum stress.…”

Aluminum effects on marine phytoplankton: implications for a revised Iron Hypothesis (Iron–Aluminum Hypothesis)

“…Aluminum toxicity to marine phytoplankton has only been intentionally tested in 1 recent years (Gillmore et al 2016;Golding et al 2015;Harford et al 2011;Saçan et al 2 2007;Xie et al 2015). The influence of Al on the growth, iron (Fe) uptake and 3 physiology of marine phytoplankton has also been reported in other studies (Liu et al 2018;Santana-Casiano et al 1997;Shi et al 2015;Stoffyn 1979;Vrieling et al 1999;5 Zhou et al 2016).…”

Genome Annotation of a Model Diatom Phaeodactylum tricornutum Using an Integrated Proteogenomic Pipeline

“…The completed P. tricornutum genome is about 27.4 megabases long and is estimated to contain 10 402 genes. Since 2008, many systemlevel studies of P. tricornutum have been conducted, which together have provided valuable information on diatom biology (Chen et al, 2014;Ge et al, 2014;Muhseen et al, 2015;Xie et al, 2015;Graff van Creveld et al, 2016;Longworth et al, 2016). However, a high-quality genome annotation of P. tricornutum is still lacking, and this has been a major obstacle for systematically understanding its molecular and cellular processes.…”