Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Energy Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.
Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, 266237, China.
Nat Commun. 2022 Mar 29;13(1):1664. doi: 10.1038/s41467-022-29337-x.
Oleaginous microalgae can produce triacylglycerol (TAG) under stress, yet the underlying mechanism remains largely unknown. Here, we show that, in Nannochloropsis oceanica, a bZIP-family regulator NobZIP77 represses the transcription of a type-2 diacylgycerol acyltransferase encoding gene NoDGAT2B under nitrogen-repletion (N+), while nitrogen-depletion (N-) relieves such inhibition and activates NoDGAT2B expression and synthesis of TAG preferably from C16:1. Intriguingly, NobZIP77 is a sensor of blue light (BL), which reduces binding of NobZIP77 to the NoDGAT2B-promoter, unleashes NoDGAT2B and elevates TAG under N-. Under N+ and white light, NobZIP77 knockout fully preserves cell growth rate and nearly triples TAG productivity. Moreover, exposing the NobZIP77-knockout line to BL under N- can double the peak productivity of TAG. These results underscore the potential of coupling light quality to oil synthesis in feedstock or bioprocess development.
产油微藻在胁迫条件下可以合成三酰基甘油（TAG），但其潜在机制尚不清楚。本研究表明，在海洋拟球藻中，bZIP 家族转录因子 NobZIP77 在氮充足（N+）条件下抑制 2 型二酰基甘油酰基转移酶编码基因 NoDGAT2B 的转录，而氮饥饿（N-）则解除这种抑制，激活 NoDGAT2B 表达，并优先利用 C16:1 合成 TAG。更有趣的是，NobZIP77 是蓝光（BL）的感受器，它降低了 NobZIP77 与 NoDGAT2B 启动子的结合，从而激活 NoDGAT2B，在 N-条件下增加 TAG 的合成。在 N+和白光条件下，NobZIP77 敲除株完全保留了细胞生长速率，并使 TAG 的生产率提高近三倍。此外，在 N-条件下，将 NobZIP77 敲除株暴露于 BL 中可以使 TAG 的峰值生产率提高一倍。这些结果强调了将光质与原料或生物工艺开发中的油脂合成相耦合的潜力。
