Subcellular localization of marine bacterial alkaline phosphatases

Area of Science:

• Marine microbiology
• Biogeochemistry
• Bioinformatics

Background:

• Bacterial alkaline phosphatases (APases) are crucial for organophosphate utilization in marine environments.
• Understanding APase subcellular localization is key to marine ecology but remains largely unknown.
• Metagenomic data offers a powerful resource to investigate marine bacterial enzymes.

Purpose of the Study:

• To identify and classify the subcellular localization of bacterial APases in marine environments using metagenomic data.
• To understand the ecological implications of APase distribution for phosphorus cycling.

Main Methods:

• Development of a bioinformatics pipeline to identify APase sequences (PhoA, PhoD, PhoX) from Global Ocean Sampling Expedition metagenomic data.
• Application of a consensus classification algorithm to predict the subcellular localization of identified APases.
• Analysis of bacterial gene content for dissolved organic phosphorus (DOP) transport and hydrolysis.

Main Results:

• Identification of 3,733 bacterial APase sequences.
• Predominant localization of APases: 41% cytoplasmic, 30% extracellular, 17% periplasmic, 12% outer membrane, and 0.9% inner membrane.
• Prevalence of glycerol phosphate (ugp) transport genes, with only half possessing the hydrolyzing ugpQ gene, supporting a role for cytoplasmic APases.

Conclusions:

• The high abundance of cytoplasmic APases suggests intracellular hydrolysis is a significant mechanism for bacterial phosphorus acquisition in surface oceans.
• Extracellular APases may enhance nutrient availability, potentially boosting marine productivity and biodiversity.
• Specific proteobacterial groups exhibit distinct strategies for DOP utilization.