Anderson Hanna S, Frischkorn Kyle R, Haley Sheean T, Dyhrman Sonya T
Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, United States.
Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States.
ISME J. 2025 Jan 2;19(1). doi: 10.1093/ismejo/wraf120.
The diazotroph Trichodesmium is an important contributor to marine dinitrogen fixation, supplying nitrogen to phytoplankton in typically nitrogen-limited ocean regions. Identifying how iron and phosphorus influence Trichodesmium activity and biogeography is an ongoing area of study, where predicting patterns of resource stress is complicated by the uncertain bioavailability of organically complexed iron and phosphorus. Here, a comparison of 26 metaproteomes from picked Trichodesmium colonies identified significantly different patterns between three ocean regions: the western tropical South Pacific, the western North Atlantic, and the North Pacific Subtropical Gyre. Trichodesmium KEGG submodule signals differed significantly across regions, and vector fitting showed that dissolved iron, dissolved inorganic phosphorus, and temperature significantly correlated with regional metaproteome patterns. Patterns of iron and phosphorus stress marker proteins previously validated in culture studies showed significant enrichment of a phosphorus stress signal in the western North Atlantic and an iron stress signal in the North Pacific. Populations in the western tropical South Pacific appeared to modulate their proteomes in response to both dissolved iron and dissolved inorganic phosphorus bioavailability, with significant enrichment of iron and phosphorus stress marker proteins, concomitant proteome restructuring, and significant decreases in the relative abundance of the dinitrogen fixation protein, NifH. These signals recapitulate established regional patterns of resource stress on phytoplankton communities released from nitrogen stress. Evaluating community stress patterns may therefore predict resource controls on diazotroph biogeography. These data highlight how Trichodesmium modulates its metabolism in the field and provide an opportunity to more accurately constrain controls on Trichodesmium biogeography and dinitrogen fixation.
固氮蓝藻束毛藻是海洋中氮固定的重要贡献者，在通常氮受限的海洋区域为浮游植物提供氮。确定铁和磷如何影响束毛藻的活性和生物地理学是一个正在进行的研究领域，由于有机络合铁和磷的生物可利用性不确定，预测资源压力模式变得复杂。在此，对从挑选的束毛藻群体中获得的26个元蛋白质组进行比较，发现三个海洋区域（西热带南太平洋、北大西洋西部和北太平洋亚热带环流）之间存在显著不同的模式。束毛藻的KEGG子模块信号在不同区域间存在显著差异，向量拟合表明溶解铁、溶解无机磷和温度与区域元蛋白质组模式显著相关。先前在培养研究中验证的铁和磷胁迫标记蛋白的模式表明北大西洋西部存在显著的磷胁迫信号富集，北太平洋存在铁胁迫信号富集。西热带南太平洋的群体似乎根据溶解铁和溶解无机磷的生物可利用性调节其蛋白质组，铁和磷胁迫标记蛋白显著富集，伴随蛋白质组重组，固氮蛋白NifH的相对丰度显著下降。这些信号概括了从氮胁迫中释放出来的浮游植物群落上已确立的区域资源胁迫模式。因此，评估群落胁迫模式可能预测对固氮蓝藻生物地理学的资源控制。这些数据突出了束毛藻在自然环境中如何调节其代谢，并为更准确地限制对束毛藻生物地理学和氮固定的控制提供了机会。
