GSE158698
The aureochrome photoreceptor PtAUREO1a is a highly effective blue light switch in diatoms
Aureochromes represent a unique type of blue-light photoreceptors that possess a blue-light sensing flavin-binding LOV-domain and a DNA-binding bZIP domain. Therefore, in contrast to other photoreceptors, aureochromes are considered as light-driven transcription factors. As a member of the essential group of marine primary producers, the pennate diatom Phaeodactylum tricornutum possesses four aureochromes (PtAUREO1a, 1b, 1c, 2). We here show a dramatic change in the global gene expression pattern of P. tricornutum cells after a shift from red to blue light. About 75% of the genes show significantly changed transcript levels already after 10 and 60 min of blue light exposure, which includes genes of major transcription factors as well as other photoreceptors. Very surprisingly, in two independent PtAureo1a knockout lines, this light induced regulation of gene expression is almost completely abolished. Such a massive and fast transcriptional change depending on only one single photoreceptor is so far unprecedented. We hence conclude that PtAUREO1a plays a key role in light regulation. Overall design: Transcriptomes of Phaeodactylum tricornutum wild type (WT) and two independent knock-out mutant clones in PtAUREO1a (1aK8, 1aK9) constantly grown in red light (0min_RL) and shifted for 10 (10min_BL) and 60 min (60min_BL) to blue light (BL). WT samples and 1aK8 samples were sequenced in biological triplicates, 1aK9 samples in biological duplicates. 1aK9 samples were additionally sequenced in two technical replicates.