Liu Zhengying, Bao Jianying, Yang Huilin, Zhang Zhibin, Yan Riming, Zhu Du
1Key Laboratory of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, 330022 China.
2Key Lab of Bioprocess Engineering of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, 330013 China.
3 Biotech. 2020 May;10(5):190. doi: 10.1007/s13205-020-02181-w. Epub 2020 Apr 3.
Perylenequinones (PQ), a class of naturally occurring polypeptides, are widely used as a clinical drug for treating skin diseases and as a photodynamic therapy against cancers and viruses. In this study, the effects of different carbon sources on PQ biosynthesis by sp. Slf14 were compared, and the underlying molecular mechanism of fructose as the sole carbon to enhance PQ production was investigated by transcriptome analysis. The results indicated that fructose enhanced PQ yield to 1753.64 mg/L, which was 1.73-fold higher than that obtained with glucose. Comparative transcriptome analysis demonstrated that most of the upregulated genes were related to transport systems, energy and central carbon metabolism in sp. Slf14 cultured in fructose. The genes involved in glycolysis and pentose phosphate pathways, and encoding citrate synthase, ATP-citrate lyase, and acetyl-CoA carboxylase were substantially upregulated, resulting in increased overall acetyl-CoA and malonyl-CoA production. However, genes involved in gluconeogenesis, glyoxylate cycle pathway, and fatty acid synthesis were significantly downregulated, resulting in higher acetyl-CoA influx for PQ formation. In particular, the putative PQ biosynthetic cluster was upregulated in sp. Slf14 cultured in fructose, leading to a significant increase in PQ production. The results of real-time qRT-PCR and related enzyme activities were also consistent with those of transcriptome analysis. These findings provide a remarkable insight into the underlying mechanism of PQ biosynthesis and pave the way for improvements in PQ production by sp. Slf14.
苝醌（PQ）是一类天然存在的多肽，被广泛用作治疗皮肤病的临床药物以及对抗癌症和病毒的光动力疗法。在本研究中，比较了不同碳源对菌株Slf14合成PQ的影响，并通过转录组分析研究了以果糖作为唯一碳源提高PQ产量的潜在分子机制。结果表明，果糖将PQ产量提高到1753.64mg/L，比葡萄糖培养时的产量高1.73倍。比较转录组分析表明，在果糖培养的菌株Slf14中，大多数上调基因与转运系统、能量和中心碳代谢有关。参与糖酵解和磷酸戊糖途径以及编码柠檬酸合酶、ATP-柠檬酸裂解酶和乙酰辅酶A羧化酶的基因显著上调，导致乙酰辅酶A和丙二酰辅酶A的总体产量增加。然而，参与糖异生、乙醛酸循环途径和脂肪酸合成的基因显著下调，导致更多的乙酰辅酶A流入用于PQ的形成。特别是，在果糖培养的菌株Slf14中，假定的PQ生物合成簇上调，导致PQ产量显著增加。实时定量RT-PCR和相关酶活性的结果也与转录组分析结果一致。这些发现为PQ生物合成的潜在机制提供了显著的见解，并为提高菌株Slf14的PQ产量铺平了道路。
