A distinct, high- affinity, alkaline phosphatase facilitates occupation of P- depleted environments by marine picocyanobacteria

• 成果类型: Article
• 署名作者: Torcello-Requena, Alberto; Murphy, Andrew R. J.; Lidbury, Ian D. E. A.; Pitt, Frances D.; Stark, Richard; Millard, Andrew D.; Puxty, Richard J.; Chen, Yin; Scanlan, David J.
• 署名单位: University of Warwick; University of Sheffield; University of Leicester; University of Birmingham
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15168
• DOI: 10.1073/pnas.2312892121
• 发表日期: 2024-05-14
• 关键词: dissolved organic phosphorus; prochlorococcus ecotypes; acquisition genes; escherichia-coli; synechococcus; genome; cyanobacteria; prediction; SEQUENCES; selection

摘要

Marine picocyanobacteria of the genera Prochlorococcus and Synechococcus , the two most abundant phototrophs on Earth, thrive in oligotrophic oceanic regions. While it is well known that specific lineages are exquisitely adapted to prevailing in situ light and temperature regimes, much less is known of the molecular machinery required to facilitate occupancy of these low - nutrient environments. Here, we describe a hitherto unknown alkaline phosphatase, Psip1, that has a substantially higher affinity for phosphomonoesters than other well - known phosphatases like PhoA, PhoX, or PhoD and is restricted to clade III Synechococcus and a subset of high light I - adapted Prochlorococcus strains, suggesting niche specificity. We demonstrate that Psip1 has undergone convergent evolution with PhoX, requiring both iron and calcium for activity and likely possessing identical key residues around the active site, despite generally very low sequence homology. Interrogation of metagenomes and transcriptomes from TARA oceans and an Atlantic Meridional transect shows that psip1 is abundant and highly expressed in picocyanobacterial populations from the Mediterranean Sea and north Atlantic gyre, regions well recognized to be phosphorus (P) - deplete. Together, this identifies psip1 as an important oligotrophy - specific gene for P recycling in these organisms. Furthermore, psip1 is not restricted to picocyanobacteria and is abundant and highly transcribed in some alpha- proteobacteria and eukaryotic algae, suggesting that such a high - affinity phosphatase is important across the microbial taxonomic world to occupy low - P environments.