The transcription factor PHR1 plays a key role in the regulation of sulfate shoot-to-root flux upon phosphate starvation in Arabidopsis.
BACKGROUND
Sulfate and phosphate are both vital macronutrients required for plant growth and development. Despite evidence for interaction between sulfate and phosphate homeostasis, no transcriptional factor has yet been identified in higher plants that affects, at the gene expression and physiological levels, the response to both elements. This work was aimed at examining whether PHR1, a transcription factor previously shown to participate in the regulation of genes involved in phosphate homeostasis, also contributed to the regulation and activity of genes involved in sulfate inter-organ transport.


RESULTS
Among the genes implicated in sulfate transport in Arabidopsis thaliana, SULTR1;3 and SULTR3;4 showed up-regulation of transcripts in plants grown under phosphate-deficient conditions. The promoter of SULTR1;3 contains a motif that is potentially recognizable by PHR1. Using the phr1 mutant, we showed that SULTR1;3 up-regulation following phosphate deficiency was dependent on PHR1. Furthermore, transcript up-regulation was found in phosphate-deficient shoots of the phr1 mutant for SULTR2;1 and SULTR3;4, indicating that PHR1 played both a positive and negative role on the expression of genes encoding sulfate transporters. Importantly, both phr1 and sultr1;3 mutants displayed a reduction in their sulfate shoot-to-root transfer capacity compared to wild-type plants under phosphate-deficient conditions.


CONCLUSIONS
This study reveals that PHR1 plays an important role in sulfate inter-organ transport, in particular on the regulation of the SULTR1;3 gene and its impact on shoot-to-root sulfate transport in phosphate-deficient plants. PHR1 thus contributes to the homeostasis of both sulfate and phosphate in plants under phosphate deficiency. Such a function is also conserved in Chlamydomonas reinhardtii via the PHR1 ortholog PSR1.
Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland.
Hatem
H
Rouached
David
D
Secco
Bulak
B
Arpat
Yves
Y
Poirier
D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D004269:DNA, Bacterial / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D016254:Mutagenesis, Insertional / Q000187:drug effects / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010710:Phosphates / Q000172:deficiency* / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism* / Q000494:pharmacology; D013460:Sulfur Isotopes; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; C514695:PHR1 protein, Arabidopsis; D010710:Phosphates; D012333:RNA, Messenger; D013431:Sulfates; D013460:Sulfur Isotopes; C036483:T-DNA; D014157:Transcription Factors
Plant Physiol. 2007 Jan;143(1):156-71
17085508
Physiol Plant. 2009 May;136(1):10-8
19508364
Plant Cell. 2006 Nov;18(11):3235-51
17114350
Biochimie. 2006 Nov;88(11):1767-71
16757083
Plant Cell Environ. 2007 Jan;30(1):85-112
17177879
Plant J. 2000 Jul;23(2):171-82
10929111
Proc Natl Acad Sci U S A. 2005 May 24;102(21):7760-5
15894620
Plant J. 2007 Jun;50(6):982-94
17461783
Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9373-7
7568135
Plant Physiol. 2004 Dec;136(4):4198-204
15531709
Proc Natl Acad Sci U S A. 2005 Aug 16;102(33):11934-9
16085708
Plant Physiol. 2003 Jun;132(2):578-96
12805589
Physiol Plant. 2004 Jan;120(1):63-73
15032878
Plant Physiol. 2010 Oct;154(2):913-26
20702726
Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5732-7
11960029
Plant Cell. 2004 Oct;16(10):2693-704
15367713
Plant Physiol. 2006 Jul;141(3):1000-11
16679417
Planta. 2008 Apr;227(5):1025-36
18094993
Plant Physiol. 2007 Apr;143(4):1789-801
17322336
BMC Plant Biol. 2010 Apr 28;10:78
20426829
Mol Plant. 2009 Jan;2(1):43-58
19529828
Biochim Biophys Acta. 1998 Dec 9;1415(1):205-18
9858733
Planta. 1997 Sep;203(1):67-74
9299791
Curr Opin Plant Biol. 2009 Jun;12(3):328-38
19501015
Plant Physiol. 1991 Nov;97(3):1087-93
16668493
Plant J. 2002 Feb;29(4):465-73
11846879
Mol Cell. 2004 Jun 18;14(6):787-99
15200956
Plant Physiol. 1996 Jan;110(1):105-110
12226174
FEBS Lett. 2007 Sep 18;581(23):4519-22
17765894
Science. 2003 Aug 1;301(5633):653-7
12893945
J Exp Bot. 2004 Aug;55(404):1765-73
15258169
Nucleic Acids Res. 2008 Jan;36(Database issue):D1009-14
17986450
Plant Physiol. 2001 Nov;127(3):963-72
11706178
Nat Protoc. 2008;3(6):1101-8
18546601
Genetics. 2009 Mar;181(3):889-905
19087952
Plant Physiol. 2002 Aug;129(4):1872-9
12177501
Plant J. 2002 Feb;29(4):475-86
11846880
Plant J. 2010 Dec;64(5):775-89
21105925
Mol Plant. 2010 Mar;3(2):314-25
20139159
Plant Physiol. 2003 Apr;131(4):1511-7
12692311
Plant Physiol. 2008 Jun;147(2):732-46
18390805
Plant Physiol. 2009 Dec;151(4):2120-32
19854858
Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18807-12
18003916
Plant Physiol. 2007 Sep;145(1):147-59
17631527
J Exp Bot. 2004 Feb;55(396):285-93
14718495
PLoS Genet. 2010 Sep 09;6(9):e1001102
20838596
Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1950-5
9465123
Plant Physiol. 2006 Jul;141(3):988-99
16679424
Plant J. 2008 Mar;53(5):731-8
17988220
Genes Dev. 2001 Aug 15;15(16):2122-33
11511543
Plant Physiol. 2008 Jun;147(2):897-911
18400935
Plant J. 2010 Jun 1;62(6):1046-57
20374528
Plant J. 2011 Feb;65(4):557-70
21288266
Plant J. 2009 Jan;57(2):313-21
18801012
Plant J. 2008 Oct;56(1):28-39
18564386
Plant Cell Environ. 2007 Dec;30(12):1499-512
17927693
Genetics. 1992 Sep;132(1):63-73
1398064
Mol Biol Cell. 2004 Sep;15(9):4089-104
15240820
Plant Physiol. 2002 Jul;129(3):1232-40
12114577
Biochim Biophys Acta. 2000 May 1;1465(1-2):236-45
10748257