Data from: Biochemical evolution in response to intensive harvesting in algae: evolution of quality and quantity

Evolutionary responses to indirect selection pressures imposed by intensive harvesting are increasingly common. While artificial selection has shown that biochemical components can show rapid and dramatic evolution, it remains unclear as to whether intensive harvesting can inadvertently induce changes in the biochemistry of harvested populations. For applications such as algal culture, many of the desirable bioproducts could evolve in response to harvesting, reducing cost-effectiveness, but experimental tests are lacking. We used an experimental evolution approach where we imposed heavy and light harvesting regimes on multiple lines of an alga of commercial interest for twelve cycles of harvesting and then placed all lines in a common garden regime for four cycles. We have previously shown that lines in a heavy harvesting regimes evolve a ‘live fast’ phenotype with higher growth rates relative to light harvesting regimes. Here, we show that algal biochemistry also differs between regimes, though they were temporarily masked by differences in density under those different regimes. Heavy harvesting regimes, evolved lower productivity of desirable bioproducts, particularly fatty acids relative to light harvesting regimes. We suggest that commercial operators wishing to maximise productivity of desirable bioproducts should maintain mother cultures, kept at higher densities (which tend to select for desirable phenotypes), and periodically restart their intensively harvested cultures to minimise the negative consequences of biochemical evolution. Our study shows that the burgeoning algal culture industry should pay careful attention to the role of evolution in intensively harvested crops as these effects are nontrivial if subtle.集约化收获所施加的间接选择压力引发的进化响应正愈发普遍。尽管人工选择研究已证实生物化学成分可发生快速且显著的进化，但目前仍不清楚集约化收获是否会无意间诱导收获种群的生物化学特征发生改变。在藻类培养等应用场景中，诸多目标生物制品可能会随收获操作发生适应性进化，进而降低成本效益，但相关实验验证仍较为匮乏。本研究采用实验进化手段，对多株具有商业价值的藻类品系分别施加高强度与低强度收获处理，历经12轮收获周期后，将所有品系置于同质园（common garden）培养体系中进行4轮培养。此前我们已证实，相较于低强度收获组，高强度收获组的藻类品系进化出了快生活表型（live fast phenotype），生长速率更高。本研究进一步发现，不同收获处理组的藻类生物化学特征同样存在差异，不过该差异在不同处理下的种群密度差异中被暂时掩盖。相较于低强度收获组，高强度收获组的目标生物制品产率更低，尤以脂肪酸类产物最为显著。我们建议，若希望最大化目标生物制品的产率，商业从业者应维持高密度的母代培养体系（该环境通常会筛选出优良表型），并定期重启高强度收获的培养体系，以尽可能降低生物化学进化带来的负面影响。本研究表明，蓬勃发展的藻类培养产业应高度关注集约化收获栽培作物中的进化作用——尽管这些效应看似细微，实则影响不容小觑。