Down-Regulation of Zeaxanthin Epoxidation in Vascular Plant Leaves Under Normal and Photooxidative Stress Conditions

β-Cyclocitral (β-CC) is a volatile compound deriving from1O2oxidation of β-carotene in plant leaves. β-CC elicits a retrograde signaling, modulating1O2-responsive genes and enhancing tolerance to photooxidative stress. Here, we show that β-CC is largely converted into β-cyclocitric acid (β-CCA) in leaves and that this metabolite is a signal involved in stress tolerance. Treatment of Arabidopsis plants with β-CCA markedly enhanced plant tolerance to drought by a mechanism different from known responses such as stomatal closure, changes in osmotic potential and jasmonate signaling. Furthermore, we show that the response to β-CCA does not fully overlap with the β-CC-dependent signaling, indicating that β-CCA induces only a branch of the β-CC signaling pathway. In addition, the protective effect of β-CCA is a conserved mechanism, being observed in a variety of plant species. This study provides a new bioactive agent with promising agronomic applications for protecting plants against drought.

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Short-term down-regulation of zeaxanthin epoxidation in Arabidopsis thaliana in response to photo-oxidative stress conditions

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/j.bbabio.2008.03.002 ◽

2008 ◽

Vol 1777 (5) ◽

pp. 462-469 ◽

Cited By ~ 36

Author(s):

Clemens Reinhold ◽

Sylvia Niczyporuk ◽

Karl Christian Beran ◽

Peter Jahns

Keyword(s):

Oxidative Stress ◽

Arabidopsis Thaliana ◽

Stress Conditions ◽

Short Term ◽

Down Regulation

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Rationale: Photosynthesis of Vascular Plants in Dim Light

Frontiers in Plant Science ◽

10.3389/fpls.2020.573881 ◽

2020 ◽

Vol 11 ◽

Author(s):

Xiaolin Wang ◽

Yong Wang ◽

Aifeng Ling ◽

Zhen Guo ◽

Muhammad Asim ◽

...

Keyword(s):

Vascular Plants ◽

Energy Demand ◽

Vascular Plant ◽

Terrestrial Ecosystems ◽

Carbon Accounting ◽

Plant Leaves ◽

Physiological Processes ◽

Research Gap ◽

Dim Light ◽

Earth’S Climate

Light dominates the earth’s climate and ecosystems via photosynthesis, and fine changes of that might cause extensive material and energy alternation. Dim light (typically less than 5 μmol photons m–2 s–1) occurs widely in terrestrial ecosystems, while the frequency, duration, and extent of that are increasing because of climate change and urbanization. Dim light is important for the microorganism in the photosynthetic process, but omitted or unconsidered in the vascular plant, because the photosynthesis in the high-light adapted vascular leaves was almost impossible. In this review, we propose limitations of photosynthesis in vascular plant leaves, then elucidate the possibility and evidence of photosynthesis in terms of energy demand, stomatal opening, photosynthetic induction, and photosynthesis-related physiological processes in dim light. This article highlights the potential and noteworthy influence of dim light on photosynthesis in vascular plant leaves, and the research gap of dim light in model application and carbon accounting.

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Distribution of the Water-Soluble Astaxanthin Binding Carotenoprotein (AstaP) in Scenedesmaceae

Marine Drugs ◽

10.3390/md19060349 ◽

2021 ◽

Vol 19 (6) ◽

pp. 349

Author(s):

Hiroki Toyoshima ◽

Ami Miyata ◽

Risako Yoshida ◽

Taichiro Ishige ◽

Shinichi Takaichi ◽

...

Keyword(s):

Water Soluble ◽

Stress Conditions ◽

Soluble Form ◽

Light Conditions ◽

Photooxidative Stress ◽

Gene Encoding ◽

Chlorella Variabilis ◽

Cell Extracts ◽

The Family ◽

Genes Encoding

Photooxidative stress-inducible water-soluble astaxanthin-binding proteins, designated as AstaP, were identified in two Scenedesmaceae strains, Coelastrella astaxanthina Ki-4 and Scenedesmus obtusus Oki-4N; both strains were isolated under high light conditions. These AstaPs are classified as a novel family of carotenoprotein and are useful for providing valuable astaxanthin in water-soluble form; however, the distribution of AstaP orthologs in other microalgae remains unknown. Here, we examined the distribution of AstaP orthologs in the family Scenedesmaceae with two model microalgae, Chlamydomonas reinhardtii and Chlorella variabilis. The expression of AstaP orthologs under photooxidative stress conditions was detected in cell extracts of Scenedesmaceae strains, but not in model algal strains. Aqueous orange proteins produced by Scenedesmaceae strains were shown to bind astaxanthin. The protein from Scenedesmus costatus SAG 46.88 was purified. It was named ScosAstaP and found to bind astaxanthin. The deduced amino acid sequence from a gene encoding ScosAstaP showed 62% identity to Ki-4 AstaP. The expression of the genes encoding AstaP orthologs was shown to be inducible under photooxidative stress conditions; however, the production amounts of AstaP orthologs were estimated to be approximately 5 to 10 times lower than that of Ki-4 and Oki-4N.

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