Genomic and phenotypic evolution of Escherichia coli in a novel citrate-only resource environment
Genomic and phenotypic evolution of Escherichia coli in a novel citrate-only resource environment
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DOI：
10.7554/elife.55414
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发表时间：
2020-05-29
期刊：
影响因子：
7.7
通讯作者：
Lenski, Richard E.
中科院分区：
文献类型：
--
作者：
Blount, Zachary D.;Maddamsetti, Rohan;Lenski, Richard E.
进化创新使种群能够殖民新的生态位。我们之前曾报道，在适应含有柠檬酸盐的最低葡萄糖培养基(DM25)的过程中，大肠杆菌种群中对柠檬酸盐(Cit(+))的有氧生长发生了进化。Cit(+)变异体也可以在只含柠檬酸的培养基(DM0)中生长，这是大肠杆菌的一个新环境。为了研究对这个生态位的适应，我们建立了两组Cit(+)种群，并在DM0或DM25中对它们进行了2500代的进化。进化的谱系获得了许多平行的突变，其中许多是由转座元件介导的。一些人还进化出了含有maeA基因的区域的扩增。出乎意料的是，一些进化的种群和克隆人的适应能力明显下降。我们还在Cit(+)克隆中发现了大量细胞死亡的证据。因此，我们的结果证明了性状的快速改进和对新的柠檬酸盐生态位的适应，同时也表明了大肠杆菌生理和柠檬酸盐生长之间的顽固不匹配。
Evolutionary innovations allow populations to colonize new ecological niches. We previously reported that aerobic growth on citrate (Cit(+)) evolved in an Escherichia coli population during adaptation to a minimal glucose medium containing citrate (DM25). Cit(+) variants can also grow in citrate-only medium (DM0), a novel environment for E. coli. To study adaptation to this niche, we founded two sets of Cit(+) populations and evolved them for 2500 generations in DM0 or DM25. The evolved lineages acquired numerous parallel mutations, many mediated by transposable elements. Several also evolved amplifications of regions containing the maeA gene. Unexpectedly, some evolved populations and clones show apparent declines in fitness. We also found evidence of substantial cell death in Cit(+) clones. Our results thus demonstrate rapid trait refinement and adaptation to the new citrate niche, while also suggesting a recalcitrant mismatch between E. coli physiology and growth on citrate.