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Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.
Author(s) -
Diaz Julia M.,
Steffen Rachel,
Sanders James G.,
Tang Yuanzhi,
Duhamel Solange
Publication year - 2019
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14630
Subject(s) - thalassiosira weissflogii , thalassiosira pseudonana , polyphosphate , phosphorus , phosphate , biology , bioavailability , diatom , phytoplankton , algae , biochemistry , environmental chemistry , nutrient , botany , chemistry , ecology , bioinformatics , organic chemistry
Summary Polyphosphates and phosphomonoesters are dominant components of marine dissolved organic phosphorus (DOP). Collectively, DOP represents an important nutritional phosphorus (P) source for phytoplankton growth in the ocean, but the contribution of specific DOP sources to microbial community P demand is not fully understood. In a prior study, it was reported that inorganic polyphosphate was not bioavailable to the model diatoms Thalassiosira weissflogii and Thalassiosira pseudonana . However, in this study, we show that the previous finding was a misinterpretation based on a technical artefact of media preparation and that inorganic polyphosphate is actually widely bioavailable to Thalassiosira spp. In fact, orthophosphate, inorganic tripolyphosphate (3polyP), adenosine triphosphate (ATP) and adenosine monophosphate supported equivalent growth rates and final growth yields within each of four strains of Thalassiosira spp. However, enzyme activity assays revealed in all cultures that cell‐associated hydrolysis rates of 3polyP were typically more than ~10‐fold higher than degradation of ATP and the model phosphomonoester compound 4‐methylumbelliferyl phosphate. These results build on prior work, which showed the preferential utilization of polyphosphates in the cell‐free exudates of Thalassiosira spp., and suggest that inorganic polyphosphates may be a key bioavailable source of P for marine phytoplankton.