Limits...
Coordination between zinc and phosphate homeostasis involves the transcription factor PHR1, the phosphate exporter PHO1, and its homologue PHO1;H3 in Arabidopsis.

Khan GA, Bouraine S, Wege S, Li Y, de Carbonnel M, Berthomieu P, Poirier Y, Rouached H - J. Exp. Bot. (2014)

Bottom Line: This work aimed at examining the effects of Zn deficiency on Pi accumulation in Arabidopsis thaliana and uncovering genes involved in the Zn-Pi synergy.Zn deprivation had a very limited effect on transcript levels of Pi-starvation-responsive genes such as AT4, IPS1, and microRNA399, or on of members of the high-affinity Pi transporter family PHT1.This was, however, not observed in a pho1 pho1;h3 double mutant, suggesting that PHO1;H3 restricts root-to-shoot Pi transfer requiring PHO1 function for Pi homeostasis in response to Zn deficiency.

View Article: PubMed Central - PubMed

Affiliation: Département de Biologie Moléculaire Végétale, Biophore, Université de Lausanne, CH-1015 Lausanne, Switzerland.

ABSTRACT
Interactions between zinc (Zn) and phosphate (Pi) nutrition in plants have long been recognized, but little information is available on their molecular bases and biological significance. This work aimed at examining the effects of Zn deficiency on Pi accumulation in Arabidopsis thaliana and uncovering genes involved in the Zn-Pi synergy. Wild-type plants as well as mutants affected in Pi signalling and transport genes, namely the transcription factor PHR1, the E2-conjugase PHO2, and the Pi exporter PHO1, were examined. Zn deficiency caused an increase in shoot Pi content in the wild type as well as in the pho2 mutant, but not in the phr1 or pho1 mutants. This indicated that PHR1 and PHO1 participate in the coregulation of Zn and Pi homeostasis. Zn deprivation had a very limited effect on transcript levels of Pi-starvation-responsive genes such as AT4, IPS1, and microRNA399, or on of members of the high-affinity Pi transporter family PHT1. Interestingly, one of the PHO1 homologues, PHO1;H3, was upregulated in response to Zn deficiency. The expression pattern of PHO1 and PHO1;H3 were similar, both being expressed in cells of the root vascular cylinder and both localized to the Golgi when expressed transiently in tobacco cells. When grown in Zn-free medium, pho1;h3 mutant plants displayed higher Pi contents in the shoots than wild-type plants. This was, however, not observed in a pho1 pho1;h3 double mutant, suggesting that PHO1;H3 restricts root-to-shoot Pi transfer requiring PHO1 function for Pi homeostasis in response to Zn deficiency.

Show MeSH
mRNA accumulation of the PHO1 gene in response to the availability of Zn in wild-type and pho1;h3 mutant plants. Plants were grown vertically on agar-solidified media containing 1mM Pi and 15 μM Zn (+Pi,+Zn), 15 μM Zn and no Pi (–Pi,+Zn), or 1mM Pi and no Zn (+Pi,–Zn). Roots of 20-d-old plants were separately harvested and mRNA accumulation was quantified by quantitative reverse-transcription PCR. mRNA abundance was normalized to the mRNA abundance of the UBQ10 control gene and expressed as relative values against wild-type plants grown in +Pi,+Zn medium. Individual measurements were obtained from the analysis of roots collected from a pool of at least 10 plants. Error bars correspond to standard deviation from three biological replicates.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC3924728&req=5

Figure 9: mRNA accumulation of the PHO1 gene in response to the availability of Zn in wild-type and pho1;h3 mutant plants. Plants were grown vertically on agar-solidified media containing 1mM Pi and 15 μM Zn (+Pi,+Zn), 15 μM Zn and no Pi (–Pi,+Zn), or 1mM Pi and no Zn (+Pi,–Zn). Roots of 20-d-old plants were separately harvested and mRNA accumulation was quantified by quantitative reverse-transcription PCR. mRNA abundance was normalized to the mRNA abundance of the UBQ10 control gene and expressed as relative values against wild-type plants grown in +Pi,+Zn medium. Individual measurements were obtained from the analysis of roots collected from a pool of at least 10 plants. Error bars correspond to standard deviation from three biological replicates.

Mentions: The PHO1 transcript accumulation level was assessed in wild-type plants and pho1;h3 mutants grown in presence or absence of Zn. The results show that PHO1 transcript level in either the wild type or pho1,h3 mutant was not significantly influenced by the presence or absence of Zn in the growth media (Fig. 9). Furthermore, the PHO1 mRNA accumulation level did not change in the pho1;h3 mutant in comparison to wild-type plants (Fig. 9). These results show that PHO1 is not regulated at the transcriptional level either by the availability of Zn or by the presence of PHO1;H3.


Coordination between zinc and phosphate homeostasis involves the transcription factor PHR1, the phosphate exporter PHO1, and its homologue PHO1;H3 in Arabidopsis.

Khan GA, Bouraine S, Wege S, Li Y, de Carbonnel M, Berthomieu P, Poirier Y, Rouached H - J. Exp. Bot. (2014)

mRNA accumulation of the PHO1 gene in response to the availability of Zn in wild-type and pho1;h3 mutant plants. Plants were grown vertically on agar-solidified media containing 1mM Pi and 15 μM Zn (+Pi,+Zn), 15 μM Zn and no Pi (–Pi,+Zn), or 1mM Pi and no Zn (+Pi,–Zn). Roots of 20-d-old plants were separately harvested and mRNA accumulation was quantified by quantitative reverse-transcription PCR. mRNA abundance was normalized to the mRNA abundance of the UBQ10 control gene and expressed as relative values against wild-type plants grown in +Pi,+Zn medium. Individual measurements were obtained from the analysis of roots collected from a pool of at least 10 plants. Error bars correspond to standard deviation from three biological replicates.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3924728&req=5

Figure 9: mRNA accumulation of the PHO1 gene in response to the availability of Zn in wild-type and pho1;h3 mutant plants. Plants were grown vertically on agar-solidified media containing 1mM Pi and 15 μM Zn (+Pi,+Zn), 15 μM Zn and no Pi (–Pi,+Zn), or 1mM Pi and no Zn (+Pi,–Zn). Roots of 20-d-old plants were separately harvested and mRNA accumulation was quantified by quantitative reverse-transcription PCR. mRNA abundance was normalized to the mRNA abundance of the UBQ10 control gene and expressed as relative values against wild-type plants grown in +Pi,+Zn medium. Individual measurements were obtained from the analysis of roots collected from a pool of at least 10 plants. Error bars correspond to standard deviation from three biological replicates.
Mentions: The PHO1 transcript accumulation level was assessed in wild-type plants and pho1;h3 mutants grown in presence or absence of Zn. The results show that PHO1 transcript level in either the wild type or pho1,h3 mutant was not significantly influenced by the presence or absence of Zn in the growth media (Fig. 9). Furthermore, the PHO1 mRNA accumulation level did not change in the pho1;h3 mutant in comparison to wild-type plants (Fig. 9). These results show that PHO1 is not regulated at the transcriptional level either by the availability of Zn or by the presence of PHO1;H3.

Bottom Line: This work aimed at examining the effects of Zn deficiency on Pi accumulation in Arabidopsis thaliana and uncovering genes involved in the Zn-Pi synergy.Zn deprivation had a very limited effect on transcript levels of Pi-starvation-responsive genes such as AT4, IPS1, and microRNA399, or on of members of the high-affinity Pi transporter family PHT1.This was, however, not observed in a pho1 pho1;h3 double mutant, suggesting that PHO1;H3 restricts root-to-shoot Pi transfer requiring PHO1 function for Pi homeostasis in response to Zn deficiency.

View Article: PubMed Central - PubMed

Affiliation: Département de Biologie Moléculaire Végétale, Biophore, Université de Lausanne, CH-1015 Lausanne, Switzerland.

ABSTRACT
Interactions between zinc (Zn) and phosphate (Pi) nutrition in plants have long been recognized, but little information is available on their molecular bases and biological significance. This work aimed at examining the effects of Zn deficiency on Pi accumulation in Arabidopsis thaliana and uncovering genes involved in the Zn-Pi synergy. Wild-type plants as well as mutants affected in Pi signalling and transport genes, namely the transcription factor PHR1, the E2-conjugase PHO2, and the Pi exporter PHO1, were examined. Zn deficiency caused an increase in shoot Pi content in the wild type as well as in the pho2 mutant, but not in the phr1 or pho1 mutants. This indicated that PHR1 and PHO1 participate in the coregulation of Zn and Pi homeostasis. Zn deprivation had a very limited effect on transcript levels of Pi-starvation-responsive genes such as AT4, IPS1, and microRNA399, or on of members of the high-affinity Pi transporter family PHT1. Interestingly, one of the PHO1 homologues, PHO1;H3, was upregulated in response to Zn deficiency. The expression pattern of PHO1 and PHO1;H3 were similar, both being expressed in cells of the root vascular cylinder and both localized to the Golgi when expressed transiently in tobacco cells. When grown in Zn-free medium, pho1;h3 mutant plants displayed higher Pi contents in the shoots than wild-type plants. This was, however, not observed in a pho1 pho1;h3 double mutant, suggesting that PHO1;H3 restricts root-to-shoot Pi transfer requiring PHO1 function for Pi homeostasis in response to Zn deficiency.

Show MeSH