Inorganic carbon limitation and light control the expression of transcripts related to the CO2-concentrating mechanism in the cyanobacterium Synechocystis sp strain PCC6803
Inorganic carbon limitation and light control the expression of transcripts related to the CO2-concentrating mechanism in the cyanobacterium Synechocystis sp strain PCC6803
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DOI：
10.1104/pp.102.019349
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发表时间：
2003-05-01
期刊：
影响因子：
7.4
通讯作者：
Badger, MR
中科院分区：
文献类型：
--
作者：
McGinn, PJ;Price, GD;Badger, MR
蓝细菌集胞藻菌株PCC 6803具有三种无机碳（Ci）吸收模式，其在Ci胁迫下是可诱导的，并且显著增强CO2浓缩机制（CCM）的效率。CI限制的影响，这些诱导型摄取系统的mRNA转录丰度和CCM的生理表达进行了详细研究，在这个蓝藻。用半定量和实时逆转录-聚合酶链反应技术评估转录丰度。细胞在光照下用无CO2空气通气30分钟，但在黑暗中不通气，将总[Ci]消耗至接近零的水平。在这些条件下，CCM的完全生理表达在2 h内是明显的。三种诱导型Ci摄取系统ndhF 3、sbtA和cmPA的转录物在Ci限制下在15分钟时显示出接近最大丰度。转录调节因子cmpR和ndhR的表达更为适度，而rbcLXS和ccmK-N操纵子以及ndhF 4/ndhD 4/chpX和ccaA基因对低Ci处理不敏感。使用实时逆转录-聚合酶链反应研究了几种CCM相关转录物表达的低Ci和光的组合要求。CmpA，ndhF 3，和sbtA强烈表达的光，但不是在黑暗中，在低Ci条件下。我们没有发现在高CO2条件下通过强光处理诱导这些或其他CCM相关基因的证据。这为单独的强光胁迫不能触发集胞藻PCC 6803中CCM相关转录本的表达提供了证据。触发诱导的CCM的高亲和力状态的潜在信号进行了讨论。
The cyanobacterium Synechocystis sp. strain PCC6803 possesses three modes of inorganic carbon (Ci) uptake that are inducible under Ci stress and that dramatically enhance the efficiency of the CO2-concentrating mechanism (CCM). The effects of Ci limitation on the mRNA transcript abundance of these inducible uptake systems and on the physiological expression of the CCM were investigated in detail in this cyanobacterium. Transcript abundance was assessed with semiquantitative and real-time reverse transcriptase-polymerase chain reaction techniques. Cells aerated with CO2-free air for 30 min in the light, but not in the dark, depleted the total [Ci] to near zero levels. Under these conditions, the full physiological expression of the CCM was apparent within 2 h. Transcripts for the three inducible Ci uptake systems, ndhF3, sbtA, and cmpA, showed near-maximal abundance at 15 min under Ci limitation. The transcriptional regulators, cmpR and ndhR, were more moderately expressed, whereas the rbcLXS and ccmK-N operons and ndhF4/ndhD4/chpX and ccaA genes were insensitive to the low-Ci treatment. The combined requirement of low Ci and light for the expression of several CCM-related transcripts was examined using real-time reverse transcriptase-polymerase chain reaction. CmpA, ndhF3, and sbtA were strongly expressed in the light, but not in the dark, under low-Ci conditions. We could find no evidence for induction of these or other CCM-related genes by a high-light treatment under high-CO2 conditions. This provided evidence that high-light stress alone could not trigger the expression of CCM-related transcripts in Synechocystis sp. PCC6803. Potential signals triggering induction of the high-affinity state of the CCM are discussed.