Cloning and characterization of a phosphate transporter gene in Dunaliella salina

Abstract

The full-length cDNA of a Na(+) -dependent Pi transport gene (DsSPT1) in Dunaliella salina was cloned by 3' and 5' Rapid Amplification of cDNA Ends (RACE), with an open reading frame (ORF) encoding 716 predicted amino acids, which exhibited 60.5% identity to that of Na(+) -dependent Pi transport 1 (DvSPT1) from Dunaliella viridis. Hydrophobicity and secondary structure prediction revealed 11 conserved transmembrane domains similar to those found in DvSPT1 from D. viridis and PHO89 from Saccharomyces cerevisiae. The result of real-time quantitative PCR showed that expression level of DsSPT1 was enhanced at first and reached its peak at 90 min after salt stress; however, D. salina cells rapidly absorbed extracellular inorganic phosphorus which was determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) during the first 5 min under salt stress. It suggested that D. salina on the absorption of inorganic phosphorus was regulated at DsSPTI posttranslational level.

The Myb‐like transcription factor phosphorus starvation response (PtPSR) controls conditional P acquisition and remodelling in marine microalgae

“…In addition to PtPSR, other TFs are likely involved in regulation of P supply to the cell. Posttranscriptional regulation might also have a role, as shown for the low affinity Na + ‐dependent P i transporter DsSPT1 in the green alga Dunaliella salina (Moseley et al ., ; Li et al ., ).…”

Functional PTB phosphate transporters are present in streptophyte algae and early diverging land plants

“…Plant PiT proteins, which comprise members of both the PTB and PHOSPHATE TRANSPORTER 2 (PHT2) subfamilies, are homologues of the fungal PiT Pi transporters ScPho89 of S. cerevisiae and NcPho4 of Neurospora crassa. The PTB and PHT2 protein subfamilies are distinct phylogenetically (Versaw & Harrison, 2002;Chung et al, 2003;Kobayashi et al, 2003;Zhao et al, 2003;Moseley et al, 2006;Tyra et al, 2007;Djouani-Tahri et al, 2011;Li et al, 2012). Moreover, members of the PHT2 protein subfamily are H + /Pi symporters located at the chloroplast envelope with no role in Pi uptake to the cell (Versaw & Harrison, 2002;Zhao et al, 2003).…”

“…To evaluate the degree of structural and functional conservation between chlorophyte and streptophyte core PTB proteins, we compared their predicted topology, subcellular location and conserved motifs (Tables 1-3). The published core PTB proteins of chlorophytes have 12 transmembrane domains (TMDs) and a large hydrophilic loop between the seventh and eighth TMDs (Chung et al, 2003;Kobayashi et al, 2003;Li et al, 2006Li et al, , 2012. TMPRED hydropathy profile prediction software (Hofmann & Stoffel, 1993) predicted a large hydrophilic loop between the seventh and eighth TMDs in all streptophyte core PTB proteins, as in the chlorophyte core PTB proteins (Table 1).…”

“…Physiological analysis of membrane transport has demonstrated that Pi uptake involves an Na + /Pi symport mechanism in at least four chlorophytes (Dunaliella salina, Ankistrodesmus braunii, Chlorella pyrenoidosa, Hydrodictyon africanum) (Raven, 1984;Weiss et al, 2001). It has been suggested that PHOSPHATE TRANSPORTER B (PTB) proteins, members of the Pi TRANSPORTER (PiT) protein family, are the Na + /Pi symporters involved in chlorophyte Pi uptake because of the sequence conservation and structural similarity of these proteins to the members of two other PiT subfamiliesthe metazoan PiT and fungal PiTknown to be functional plasma membrane Na + /Pi symporters (Chung et al, 2003;Kobayashi et al, 2003;Li et al, 2006Li et al, , 2012Moseley et al, 2006;Guan et al, 2008;Djouani-Tahri et al, 2011). Consistent with the hypothesized Na + /Pi symporter activity is the observation that PTB proteins of the chlorophyte Dunaliella viridis increase the Na + sensitivity of a yeast mutant with no plasma membrane Na + export pumps (Li et al, 2006).…”

Effects of Long Chain Fatty Acid Synthesis and Associated Gene Expression in Microalga Tetraselmis sp.

“…Studies on the expression of BKAS have found an increase of gene expression in Dunaliella salina as a result of salinity shifts from 0.5 to 3.5 M: this corresponded with an increased proportion of longer chain FAs in cell membranes [26]. Bioinformatics analyses decoding the microalgal genome have accelerated the identification of genes participating in the synthesis of molecules involved in microalgal survival mechanisms, such as osmoregulation proteins, as well as FA synthesis [26,27,28,29]. The identification of long-chain desaturases has given researches the ability to characterize and study their function in other organisms, such as yeast and plants [30,31,32].…”