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选择维持了共生蓝藻细菌的光合作用,尽管其与主体的冗余性

Liam Friar¹, Kyle Keepers², Arkadiy I Garber³

¹Department of Geological Sciences, University of Colorado, Boulder, CO, USA.

Molecular biology and evolution

|August 12, 2025

概括

垂直遗传的蓝藻共生体,如阿佐拉中的Trichormus azollae,由于对能量捕获基因的强烈选择,保留了光合作用. 基因丢失正在进行中,但基本功能仍然对共生至关重要.

科学领域:

微生物生态学微生物生态学
进化基因组学进化基因组学
共生系统是共生系统.

背景情况:

垂直遗传的共生生物面临着独特的进化压力,包括减少有效种群大小 (Ne) 和放松的净化选择.
这些因素会随着时间的推移导致基因丢失,改变共生体的遗传构成和功能能力.
进化为光合作用宿主的共生体的亚松托菌蓝藻细菌为研究保留或丢失的祖先特征提供了一个模型,例如光合作用.

研究的目的:

研究垂直遗传的蓝菌共生体Trichormus azollae中保留光合作用的基因组基础.
与自由生活的亲属相比,在T. azollae中识别选择中的基因和丢失的基因.
了解能量捕获和固定在这种共生中长期维持光合作用的作用.

主要方法:

八个T. azollae菌株和自由生活的蓝藻细菌亲属的比较基因组学.
应用分子进化模型来检测遗传漂移和选择的特征.
对基因丢失模式的分析和在不同的功能途径中净化选择压力.

主要成果:

在T. azollae中基因漂移的全基因组标志表明Ne. azollae的长期减少.
参与核糖体功能和光合作用光反应的基因受到强烈的净化选择.
固定和固定碳的基因表现出不同的选择压力,在菌株之间没有观察到光反应基因的损失.

结论:

在T. azollae中,光合作用的保留是由对能量捕获至关重要的基因的强烈净化选择驱动的,这可能支持固化.
持续的基因损失发生,但关键的共生功能保持.
这项研究强调了垂直遗传的共生体的动态进化轨迹以及宿主-共生体共同进化的重要性.

关键词:

阿佐拉阿佐拉 Azolla 阿佐拉阿佐拉这种鱼叫做Trichormus azollae.进行比较的基因组学.遗传漂移是一种遗传漂移.分子进化分子演变.共生基因组减小的共生.

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