Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.
Preferential utilization of inorganic polyphosphate over other bioavailable phosphorus sources by the model diatoms Thalassiosira spp.
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DOI：
10.1111/1462-2920.14630
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发表时间：
2019-07-01
影响因子：
5.1
通讯作者：
Duhamel, Solange
中科院分区：
文献类型：
--
作者：
Diaz, Julia M.;Steffen, Rachel;Duhamel, Solange
多聚磷酸盐和磷酸单酯是海洋溶解有机磷（DOP）的主要组分。总的来说，DOP代表了海洋浮游植物生长的重要营养磷（P）来源，但具体DOP来源对微生物群落P需求的贡献尚未完全了解。在先前的研究中，据报道，无机多磷酸盐对模式硅藻海链藻和海链藻没有生物可利用性。然而，在这项研究中，我们表明，以前的发现是一个误解的基础上的技术人工制品的媒体准备和无机多磷酸盐实际上是广泛的生物利用海链藻种。事实上，正磷酸盐、无机三聚磷酸盐（3 polyP）、三磷酸腺苷（ATP）和单磷酸腺苷支持海链藻属的四种菌株中的每一种的相等生长速率和最终生长产量。然而，酶活性测定显示，在所有的文化，细胞相关的水解率3 polyP通常超过类似的10倍以上的ATP和模型磷酸单酯化合物4-甲基伞形酮磷酸酯的降解。这些结果建立在先前的工作基础上，先前的工作显示了海链藻属物种的无细胞分泌物中多磷酸盐的优先利用，无机多聚磷酸盐可能是海洋浮游植物磷的重要生物有效来源。
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 similar to 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.