Multicellularity drives ecological diversity in a long-term evolution experiment.
Multicellularity drives ecological diversity in a long-term evolution experiment.
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在长期进化实验中，多细胞性驱动了生态多样性。
DOI：
10.1038/s41559-024-02391-y
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发表时间：
2024
影响因子：
16.8
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中科院分区：
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光养代谢，即捕获光以获取能量，是一项关键的生物创新，它极大地增加了生物圈可用的总能量。以叶绿素为基础的光合作用是最熟悉的光营养代谢，但以视黄醛为基础的微生物紫红质通过更简单的机制，传递的光能几乎与叶绿素一样多，并且在更多的分类群中被发现。虽然该系统显然通过水平基因转移广泛传播，但对于具有复杂内膜结构的真核细胞如何水平获得视紫红质基因（在原核生物中具有系统发育起源5,6）或它们提供适应度优势的条件知之甚少。为了解决这一知识差距，我们试图确定酿酒酵母，一种没有已知光养进化史的异养酵母，在获得单一视紫红质基因后是否可以作为兼性光养酵母。我们从黑穗病菌（Ustilago maydis）中插入了一个视紫红质基因，该基因编码位于液泡的质子泵，液泡是一种通常通过v型旋转atp酶酸化的细胞器，允许视紫红质补充异营养代谢。对修饰细胞的生理探针表明，它们可以利用光能使细胞质脱酸，证明了视紫红质改善饥饿和静止影响的能力。此外，我们还发现，在光照条件下，带有酵母的视紫红质获得了一种选择优势，比它们的非光养祖先或在黑暗中培养的带有视紫红质的酵母增殖得更快。这些结果强调，即使在真核生物中，视紫红质也可以轻松地水平转移，提供新的生物学功能，而无需首先进行进化优化。
Phototrophic metabolism, the capture of light for energy, was a pivotal biological innovation that greatly increased the total energy available to the biosphere. Chlorophyll-based photosynthesis is the most familiar phototrophic metabolism, but retinal-based microbial rhodopsins transduce nearly as much light energy as chlorophyll does, 1 via a simpler mechanism, and are found in far more taxonomic groups. Although this system has apparently spread widely via horizontal gene transfer, 2–4 little is known about how rhodopsin genes (with phylogenetic origins within prokaryotes 5, 6) are horizontally acquired by eukaryotic cells with complex internal membrane architectures or the conditions under which they provide a fitness advantage. To address this knowledge gap, we sought to determine whether Saccharomyces cerevisiae, a heterotrophic yeast with no known evolutionary history of phototrophy, can function as a facultative photoheterotroph after acquiring a single rhodopsin gene. We inserted a rhodopsin gene from Ustilago maydis, 7 which encodes a proton pump localized to the vacuole, an organelle normally acidified via a V-type rotary ATPase, allowing the rhodopsin to supplement heterotrophic metabolism. Probes of the physiology of modified cells show that they can deacidify the cytoplasm using light energy, demonstrating the ability of rhodopsins to ameliorate the effects of starvation and quiescence. Further, we show that yeast-bearing rhodopsins gain a selective advantage when illuminated, proliferating more rapidly than their non-phototrophic ancestor or rhodopsin-bearing yeast cultured in the dark. These results underscore the ease with which rhodopsins may be horizontally transferred even in eukaryotes, providing novel biological function without first requiring evolutionary optimization.