Here we report the development of a high-throughput selection protocol using random mutagenesis and live single-cell sorting to isolate cell lines from the algae Dunaliella tertiolecta with reduced chlorophyll content, with the aim to optimise the antenna size for increased photosynthetic efficiency. Two promising cell lines (lca1 and lca2) have been isolated that display a truncated light-harvesting antenna, and hence improved photosynthetic energy conversion efficiency by increasing the light intensity at which photosynthesis becomes saturated (I_s). lca1 and lca2 differ significantly: the lca2 phenotype retains an ability to alter its antenna size in response to varying light intensity, whereas lca1 appears to have lost this ability and is ‘locked’ to a truncated antenna and high-light phenotype. Despite these clear differences, transcriptomic analysis shows that the expression profiles for differentially expressed nuclear-encoded photosynthetic genes is similar in both lca1 and lca2, possibly suggesting underlying mutations in the regulation of photosynthesis are causing the observed changes in phenotype rather than mutations impacting specific components of the photosynthetic apparatus. The combination of approaches presented here offer the capacity to substantially improve photosynthetic efficiency from any microalgal species irrespective of the extent to which it has been characterised genetically or the availability of molecular tools for rational engineering. It thus offers the potential to begin to exploit the huge natural diversity of microalgae for enhanced biomass production.

在这里，我们报告了使用随机诱变和活单细胞分选从藻类杜氏藻中分离出具有低叶绿素含量的高通量选择协议的进展，目的是优化天线尺寸以提高光合效率。已分离出显示截短的光收集天线的两个有希望的细胞系（lca1和lca2），并因此通过增加光合作用达到饱和的光强度（I _s）来提高光合作用的能量转换效率。lca1和lca2明显不同：lca2表型保留了响应于变化的光强度而改变其天线尺寸的能力，而lca1似乎已经失去了这种能力，并被“锁定”到截短的天线和高光表型。尽管存在这些明显的差异，但转录组分析显示，差异表达的核编码光合基因的表达谱在lca1和lca2中相似，可能暗示光合作用调控中的潜在突变正在引起表型的观察到的变化，而不是突变影响光合作用设备的特定组件。这里介绍的方法的组合提供了从任何微藻类物种中大幅提高光合作用效率的能力，而不论其遗传学表征的程度或进行合理工程设计的分子工具的可用性。因此，它提供了开始开发微藻的巨大自然多样性以增强生物量生产的潜力。