Transcriptional patterns identify resource controls on the diazotroph Trichodesmium in the Atlantic and Pacific oceans
Transcriptional patterns identify resource controls on the diazotroph Trichodesmium in the Atlantic and Pacific oceans
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DOI：
10.1038/s41396-018-0087-z
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发表时间：
2018-02
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通讯作者：
Mónica Rouco;K. Frischkorn;S. T. Haley;Harriet Alexander;S. Dyhrman
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文献类型：
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作者：
Mónica Rouco;K. Frischkorn;S. T. Haley;Harriet Alexander;S. Dyhrman
由于这种生物对低营养海洋环流中碳和氮循环的控制，对固氮蓝藻trichodesmiumn进行了深入的研究。虽然铁（Fe）和磷(P)的生物利用度被认为是木霉分布和活动的主要驱动因素，但确定资源控制对木霉具有挑战性，因为铁和磷通常是有机络合的，它们对混合群落中单一物种的生物利用度很难限制。此外，铁和磷的地球化学是通过金属酶的活性联系起来的，比如碱性磷酸酶PhoX和PhoA，它们被微生物用来获取溶解的有机磷（DOP）。本研究发现北大西洋（NASG）和北太平洋副热带环流（NPSG）中entrichodesium特异性转录模式与铁和磷生物地球化学模式之间存在显著相关性，且NPSG中铁胁迫标记相对富集，而北太平洋副热带环流中磷胁迫标记相对富集。我们还观察到NASG中需要铁的PhoX转录本和NPSG中对铁不敏感的PhoA转录本的富集差异，这表明金属酶开关可能用于减轻铁在铁代谢中的限制。这一特性可能是木霉在不同生态系统中成功的基础。
The N2-fixing cyanobacteriumTrichodesmiumis intensely studied because of the control this organism exerts over the cycling of carbon and nitrogen in the low nutrient ocean gyres. Although iron (Fe) and phosphorus (P) bioavailability are thought to be major drivers ofTrichodesmiumdistributions and activities, identifying resource controls onTrichodesmiumis challenging, as Fe and P are often organically complexed and their bioavailability to a single species in a mixed community is difficult to constrain. Further, Fe and P geochemistries are linked through the activities of metalloenzymes, such as the alkaline phosphatases (APs) PhoX and PhoA, which are used by microbes to access dissolved organic P (DOP). Here we identified significant correlations betweenTrichodesmium-specific transcriptional patterns in the North Atlantic (NASG) and North Pacific Subtropical Gyres (NPSG) and patterns in Fe and P biogeochemistry, with the relative enrichment of Fe stress markers in the NPSG, and P stress markers in the NASG. We also observed the differential enrichment of Fe-requiring PhoX transcripts in the NASG and Fe-insensitive PhoA transcripts in the NPSG, suggesting that metalloenzyme switching may be used to mitigate Fe limitation of DOP metabolism inTrichodesmium. This trait may underpinTrichodesmiumsuccess across disparate ecosystems.