Chen Yuanyuan, Yin Jiaojiao, Wei Jin, Zhang Xuezhen
Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt, Ministry of Education, College of Fisheries, Huazhong Agricultural University, Shizishan street 1, Wuhan 430070, China.
College of Life Science, Jianghan University, Wuhan 430070, China.
Microorganisms. 2020 Jun 1;8(6):832. doi: 10.3390/microorganisms8060832.
Massive blooms of cyanobacteria frequently occur with microcystin (MC) production. Cyanobacteria are exposed to copper stresses such as copper algaecides which are often used to remove cyanobacterial blooms. However, copper increased the MC production of cyanobacteria, and the underlying mechanism remains unclear. The present study investigated the relationship between copper exposure (0.5 and 3 µM) and MC synthesis in PCC 7806. The study concluded that the content of intracellular MCs increased by nearly two times both in 0.5 and 3 µM copper. High-throughput RNA sequencing (RNA-seq) provided evidence that copper mainly attacked Fe-S clusters, with evidence of changes in iron, sulfur, iron uptake regulators (fur), glutaredoxins and dehydratase genes. The transcription of numbers of genes implicated in iron uptake, MC synthesis and was also evaluated with quantitative real-time PCR (qRT-PCR). In these three Cu treatment groups, the amount of MCs increased as copper elevated. As the expression of gene was directly regulated by FurA and copper ions affected the expression of the FurA-related genes, we believed that MC synthesis genes were controlled by copper. This study has made a further understanding of the mechanism of the increase in MC synthesis of PCC 7806 treated with copper-based algaecides. We aimed to understand the mechanism of copper ion influencing the synthesis of MCs.
蓝藻大量繁殖时常常会产生微囊藻毒素（MC）。蓝藻会受到铜胁迫，例如常用的用于去除蓝藻水华的铜基除藻剂。然而，铜会增加蓝藻的微囊藻毒素产量，其潜在机制仍不清楚。本研究调查了铜暴露（0.5和3 μM）与集胞藻PCC 7806中微囊藻毒素合成之间的关系。研究得出结论，在0.5 μM和3 μM铜浓度下，细胞内微囊藻毒素的含量均增加了近两倍。高通量RNA测序（RNA-seq）提供了证据，表明铜主要攻击铁硫簇，有铁、硫、铁摄取调节因子（fur）、谷氧还蛋白和脱水酶基因变化的证据。还通过定量实时PCR（qRT-PCR）评估了与铁摄取、微囊藻毒素合成相关的多个基因的转录情况。在这三个铜处理组中，微囊藻毒素的量随着铜浓度的升高而增加。由于基因的表达直接受FurA调控，且铜离子影响FurA相关基因的表达，我们认为微囊藻毒素合成基因受铜的控制。本研究进一步了解了用铜基除藻剂处理后集胞藻PCC 7806微囊藻毒素合成增加的机制。我们旨在了解铜离子影响微囊藻毒素合成的机制。
