Role of phosphate transport system component pstB1 in phosphate internalization by Nostoc punctiforme

Hudek, Lee, Premachandra, Dasun, Webster, Wesley and Brau, Lambert 2016, Role of phosphate transport system component pstB1 in phosphate internalization by Nostoc punctiforme, Applied and environmental microbiology, vol. 82, no. 21, pp. 6344-6356, doi: 10.1128/AEM.01336-16.

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Title Role of phosphate transport system component pstB1 in phosphate internalization by Nostoc punctiforme
Author(s) Hudek, LeeORCID iD for Hudek, Lee
Premachandra, Dasun
Webster, WesleyORCID iD for Webster, Wesley
Brau, LambertORCID iD for Brau, Lambert
Journal name Applied and environmental microbiology
Volume number 82
Issue number 21
Start page 6344
End page 6356
Total pages 13
Publisher American Society for Microbiology
Place of publication Washington, D.C.
Publication date 2016-11
ISSN 1098-5336
Summary In bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacterium Nostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified. pstB1 was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined that pstB1 mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed when pstB2, pstB3, and pstB4 mRNA levels increased, particularly in cells starved of phosphate. The overexpression of pstB1 increased phosphate uptake by N. punctiforme and was shown to functionally complement the loss of PstB in E. coli PstB knockout (PstB(-)) mutants. The knockout of pstB1 in N. punctiforme did not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in the pstB2, pstB3, and pstB4 mRNA levels. This study provides novel in vivo evidence that PstB1 plays a functional role in phosphate uptake in N. punctiforme IMPORTANCE: Cyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons in Nostoc punctiforme and functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genes pstB2, pstB3, and pstB4 show alterations in expression to compensate for the deletion of pstB1 The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria like N. punctiforme, allowing them to thrive in low-phosphate environments.
Language eng
DOI 10.1128/AEM.01336-16
Field of Research 060599 Microbiology not elsewhere classified
MD Multidisciplinary
Socio Economic Objective 970106 Expanding Knowledge in the Biological Sciences
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2016, American Society for Microbiology
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