The WRKY6 Transcription Factor ModulatesPHOSPHATE1Expression in Response to Low Pi Stress inArabidopsis   

Abstract

Arabidopsis thaliana WRKY family comprises 74 members and some of them are involved in plant responses to biotic and abiotic stresses. This study demonstrated that WRKY6 is involved in Arabidopsis responses to low-Pi stress through regulating PHOSPHATE1 (PHO1) expression. WRKY6 overexpression lines, similar to the pho1 mutant, were more sensitive to low Pi stress and had lower Pi contents in shoots compared with wild-type seedlings and the wrky6-1 mutant. Immunoprecipitation assays demonstrated that WRKY6 can bind to two W-boxes of the PHO1 promoter. RNA gel blot and b-glucuronidase activity assays showed that PHO1 expression was repressed in WRKY6-overexpressing lines and enhanced in the wrky6-1 mutant. Low Pi treatment reduced WRKY6 binding to the PHO1 promoter, which indicates that PHO1 regulation by WRKY6 is Pi dependent and that low Pi treatment may release inhibition of PHO1 expression. Protein gel blot analysis showed that the decrease in WRKY6 protein induced by low Pi treatment was inhibited by a 26S proteosome inhibitor, MG132, suggesting that low Pi-induced release of PHO1 repression may result from 26S proteosome-mediated proteolysis. In addition, WRKY42 also showed binding to W-boxes of the PHO1 promoter and repressed PHO1 expression. Our results demonstrate that WRKY6 and WRKY42 are involved in Arabidopsis responses to low Pi stress by regulation of PHO1 expression.

The rice transcription factor OsWRKY47 is a positive regulator of the response to water deficit stress

“…However, some interesting examples are available in the literature; AtWRKY18 which is involved in ABA signaling and salt tolerance (Chen et al 2010;Shang et al 2010) binds the sequence (C/A)TTGAC(T/G). AtWRKY6, a negative regulator of the response to low Pi levels and a positive regulator to low brassinosteroid levels (Chen et al 2009;Kasajima et al 2010), binds specifically the sequence GTTGACC, a sequence similar to that bound by OsWRKY47 (Ciolkowski et al 2008). The same cis-element bound by OsWRKY47 is also bound by AtWRKY11 (Ciolkowski et al 2008) which e Cysteine-rich repeat secretory protein (CRRSP) transcript levels in WT and in mutant Osw47-1 plants.…”

Transcriptional responses of tolerant and susceptible soybeans to soybean aphid (Aphis glycines Matsumura) herbivory

“…No differences in gene expression were found in the day 5 time point of the tolerant genotype nor in either time points of the susceptible soybean (Tables 3, 4). In plants, cytochrome P450s, some of which are involved in jasmonic acid (JA)-mediated defense responses (Park et al 2002), have been shown to be induced in aphid-resistant wheat and sorghum in response to Diuraphis noxia and Schizaphis graminum, Early Fe deficiency response (Murgia et al 2011) Glyma18g10330 2.1 0.06 AT4G04450 WRKY family transcription factor (WRKY 6,31,36,42,47) Responses to low-Pi stress (Chen et al 2009) Glyma10g34160 2.0 6.56E-04 AT1G20510 OPC-8:0 CoA ligase1 Acyl-coenzyme A synthetase family (Kienow et al 2008) respectively (Park et al 2005a, b;Boyko et al 2006). Our data generally support these earlier findings.…”

“…AtWRKY42 and WRKY6 are part of the WRKY group II-b family. Several of the WRKY genes that are members of the group II-b are involved in Arabidopsis response to lowPi (phosphate) stress by regulating PHOSPHATE1 (PHO1) expression (Chen et al 2009). Coincidently, Glyma10g04230 coding for a phosphate transporter is significantly enriched in tolerant plants 15 days after aphid introduction.…”

Deciphering the Physalis floridana Double-Layered-Lantern1 Mutant Provides Insights into Functional Divergence of the GLOBOSA Duplicates within the Solanaceae

“…For subcellular localization studies, the ORFs of PFGLO1 and PFGLO2 were cloned into the Super1300 expression vector (Chen et al, 2009) using the XbaI/ KpnI (Roche) restriction sites and fused to GFP. For the BiFC assays, the ORFs of PFGLO1, PFGLO2, and PFDEF were cloned into the pSPYNE-35S and pSPYCE-35S vector pair (Walter et al, 2004) using the XbaI/BamHI (Roche) restriction sites.…”