Key Laboratory of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, 330022, China.
Key Lab of Bioprocess Engineering of Jiangxi Province, College of life sciences, Jiangxi Science and Technology Normal University, Nanchang, 330013, China.
Appl Microbiol Biotechnol. 2018 Jan;102(1):153-163. doi: 10.1007/s00253-017-8602-0. Epub 2017 Nov 2.
Perylenequinones (PQ) that notably produce reactive oxygen species upon exposure to visible light are a class of photoactivated polyketide mycotoxins produced by fungal plant pathogens such as Shiraia sp. The involvement of Ca/calmodulin (CaM) signalling in PQ biosynthesis was investigated by submerged culturing of Shiraia sp. Slf14, a species that produces hypocrellins HA and HB and elsinochromes EA, EB, and EC. Our results showed that the total content of PQ reached 1894.66 ± 21.93 mg/L under optimal conditions of Ca addition, which represents a 5.8-fold improvement over controls. The addition of pharmacological Ca sensor inhibitors strongly inhibited PQ production, which indicates that Ca/CaM signalling regulates PQ biosynthesis. The expression levels of Ca sensor and PQ biosynthetic genes were downregulated following addition of inhibitors but were upregulated upon addition of Ca. Inhibition was partially released by external Ca supplementation. Fluo-3/AM experiments revealed that similar cytosolic Ca variation occurred under these conditions. These results demonstrated that Ca signalling via the CaM transduction pathway plays a pivotal role in PQ biosynthesis.
倍半萜醌（PQ）在暴露于可见光时会产生活性氧，是一类光激活聚酮类真菌毒素，由真菌植物病原体如竹黄菌属等产生。通过对产生 Hypocrellin HA 和 HB 以及 elsinochrome EA、EB 和 EC 的 Shiraia sp. Slf14 进行深层培养，研究了 Ca/钙调蛋白（CaM）信号在 PQ 生物合成中的作用。结果表明，在添加 Ca 的最佳条件下，PQ 的总量达到 1894.66±21.93mg/L，比对照提高了 5.8 倍。药理 Ca 传感器抑制剂的添加强烈抑制 PQ 的产生，表明 Ca/CaM 信号调节 PQ 的生物合成。抑制剂的添加使 Ca 传感器和 PQ 生物合成基因的表达水平下调，但 Ca 的添加使表达水平上调。外源 Ca 的补充部分释放了抑制作用。Fluo-3/AM 实验表明，在这些条件下，细胞溶质 Ca 发生类似的变化。这些结果表明，通过 CaM 转导途径的 Ca 信号在 PQ 生物合成中起着关键作用。
