Abstract The Antarctic endemic brown alga Ascoseira mirabilis is physically and physiologically well adapted to the extreme polar environment. To better understand the molecular strategies associated with stress adaptation, the transcriptome of A. mirabilis was sequenced, and its antioxidant enzyme genes were identified and compared with other algae. A total of 126,576 unigenes with a mean length of 734 bp and N50 of 1174 bp was assembled from the transcriptome data. Phylogenetic analysis revealed that dramatic evolutionary changes had occurred in the brown algal superoxide dismutases (SODs) and class I peroxidases that were not consistent with the phylogeny of the species. Fe/Mn SODs are more prevalent in brown algae than in red and green algae. Two additional Fe-SODs in A. mirabilis were phylogenetically closely related to those of green algae, but not to those in other brown algae. We also identified three A. mirabilis ascorbate peroxidase (APx) genes that had a different origin from other brown algal APxs. The SOD and APx genes specifically identified in A. mirabilis will be crucial for understanding the evolution of the algal antioxidant enzymes that contribute to ecological success under extreme environmental conditions in the Antarctic region.

中文翻译：

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南极地方性褐藻 Ascoseira mirabilis (Ascoseirales, Phaeophyceae) 中的超氧化物歧化酶和抗坏血酸过氧化物酶基因：从头转录组的数据挖掘

摘要 南极特有褐藻Ascoseira mirabilis 在生理和生理上都很好地适应了极端的极地环境。为了更好地了解与应激适应相关的分子策略，对奇异果的转录组进行了测序，并对其抗氧化酶基因进行了鉴定并与其他藻类进行了比较。从转录组数据中组装了总共 126,576 个平均长度为 734 bp 和 N50 为 1174 bp 的 unigenes。系统发育分析表明，褐藻超氧化物歧化酶 (SOD) 和 I 类过氧化物酶发生了显着的进化变化，与物种的系统发育不一致。Fe/Mn SOD 在褐藻中比在红藻和绿藻中更为普遍。A. mirabilis 中的另外两种 Fe-SOD 在系统发育上与绿藻密切相关，但不适用于其他褐藻中的那些。我们还确定了三个奇异果抗坏血酸过氧化物酶 (APx) 基因，它们的起源与其他褐藻 APx 不同。在奇异果中特别鉴定的 SOD 和 APx 基因对于了解有助于南极地区极端环境条件下生态成功的藻类抗氧化酶的进化至关重要。