中温红藻 Giordanoi 光合器官的驯化

Acclimation of photosynthetic apparatus in the mesophilic red alga Dixoniella giordanoi

 

 

 

Keywords:Algal metabolism; electron transport capacity; lutein cycle
关键词:藻类代谢;电子传输能力;叶黄素循环

非哺乳动物:原生生物
作者:Fattore N, Savio S, Vera-Vives AM, Battistuzzi M, Moro I, La Rocca N, Morosinotto T
出版期刊:《Physiologia Plantarum》 2021/6/25

 

Abstract:

Eukaryotic algae are photosynthetic organisms capable of exploiting sunlight to fix carbon dioxide into biomass with highly variable genetic and metabolic features. Information on algae metabolism from different species is inhomogeneous and, while green algae are, in general, more characterized, information on red algae is relatively scarce despite their relevant position in eukaryotic algae diversity. Within red algae, the best-known species are extremophiles or multicellular, while information on mesophilic unicellular organisms is still lacunose. Here, we investigate the photosynthetic properties of a recently isolated seawater unicellular mesophilic red alga, Dixoniella giordanoi. Upon exposure to different illuminations, D. giordanoi shows the ability to acclimate, modulate chlorophyll content, and re-organize thylakoid membranes. Phycobilisome content is also largely regulated, leading to almost complete disassembly of this antenna system in cells grown under intense illumination. Despite the absence of a light-induced xanthophyll cycle, cells accumulate zeaxanthin upon prolonged exposure to strong light, likely contributing to photoprotection. D. giordanoi cells show the ability to perform cyclic electron transport that is enhanced under strong illumination, likely contributing to the protection of Photosystem I from over-reduction and enabling cells to survive PSII photoinhibition without negative impact on growth.

 

文章摘要:

真核藻类是能够利用阳光将二氧化碳固定到具有高度可变的遗传和代谢特征的生物质中的光合生物。来自不同物种的藻类代谢的信息是不均匀的,虽然绿藻通常更具特征性,但红藻的信息相对稀少,尽管它们在真核藻类多样性中具有相关地位。在红藻中,最知名的物种是极端微生物或多细胞生物,而有关嗜温单细胞生物的信息仍然是缺糖。在这里,我们研究了最近分离的海水单细胞嗜温红藻 Dixoniella giordanoi 的光合特性。在暴露于不同的光照下,D. giordanoi 显示出适应、调节叶绿素含量和重组类囊体膜的能力。藻胆体的含量也在很大程度上受到调节,导致在强光照下生长的细胞中这种天线系统几乎完全分解。尽管没有光诱导的叶黄素循环,但细胞在长时间暴露于强光下会积累玉米黄质,这可能有助于光保护。 D. giordanoi 细胞表现出在强光照下增强的循环电子传输能力,这可能有助于保护光系统 I 免于过度还原,并使细胞能够在 PSII 光抑制下存活,而不会对生长产生负面影响。

 


点击链接即可查看和下载文章:https://onlinelibrary.wiley.com/doi/10.1111/ppl.13489
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