Transcriptomics-Aided Dissection of the Intracellular and Extracellular Roles of Microcystin in Microcystis aeruginosa PCC 7806
Transcriptomics-Aided Dissection of the Intracellular and Extracellular Roles of Microcystin in Microcystis aeruginosa PCC 7806
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DOI：
10.1128/aem.02601-14
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发表时间：
2015-01-01
影响因子：
4.4
通讯作者：
Dittmann, Elke
中科院分区：
文献类型：
--
作者：
Makower, A. Katharina;Schuurmans, J. Merijn;Dittmann, Elke
最近的研究已经提供了强有力的肝毒素微囊藻毒素(MC)在蓝藻水华形成中的细胞内和细胞外作用的证据。在这里，我们研究了野生型铜绿假单胞菌PCC7806和微囊藻毒素缺陷型Delta mcyB突变体(MC-LR)在弱光条件下的转录。基因芯片和定量聚合酶链式反应获得的转录数据显示，中枢中间代谢、光合作用和能量代谢基因的相对表达存在显著差异。特别是，这些数据为微囊藻毒素缺失突变体中较低的光系统I(PSI)与光系统II(PSII)比率和更明显的碳限制提供了证据。有趣的是，只有6%的转录差异可以通过外源微囊藻毒素-LR的添加来补充。这种MC信号效应仅见于次生代谢类基因。孤儿聚酮合成酶基因簇IPF38-51在弱光下被外界MC-LR特异性下调。我们的数据表明次生代谢物之间存在分层的、依赖于光的串扰，并支持微囊藻MC在细胞内和细胞外的作用。
Recent studies have provided evidence for both intracellular and extracellular roles of the potent hepatotoxin microcystin (MC) in the bloom-forming cyanobacterium Microcystis. Here, we surveyed transcriptomes of the wild-type strain M. aeruginosa PCC 7806 and the microcystin-deficient Delta mcyB mutant under low light conditions with and without the addition of external MC of the LR variant (MC-LR). Transcriptomic data acquired by microarray and quantitative PCR revealed substantial differences in the relative expression of genes of the central intermediary metabolism, photosynthesis, and energy metabolism. In particular, the data provide evidence for a lower photosystem I (PSI)-to-photosystem II (PSII) ratio and a more pronounced carbon limitation in the microcystin-deficient mutant. Interestingly, only 6% of the transcriptional differences could be complemented by external microcystin-LR addition. This MC signaling effect was seen exclusively for genes of the secondary metabolism category. The orphan polyketide synthase gene cluster IPF38-51 was specifically downregulated in response to external MC-LR under low light. Our data suggest a hierarchical and light-dependent cross talk of secondary metabolites and support both an intracellular and an extracellular role of MC in Microcystis.