Phosphate Homeostasis and Root Development in Arabidopsis Are Synchronized by the Zinc Finger Transcription Factor ZAT6

Abstract

Phosphorus availability is limited in many natural ecosystems. Plants adapt to phosphate (Pi) deficiency by complex molecular processes. There is growing evidence suggesting that transcription factors are key components in the regulation of these processes. In this study, we characterized the function of ZAT6 (zinc finger of Arabidopsis 6), a cysteine-2/histidine-2 zinc finger transcription factor that is responsive to Pi stress. ZAT6 is induced during Pi starvation and localizes to the nucleus. While the RNAi suppression of ZAT6 appeared to be lethal, its overexpression affects root development and retards seedling growth as a result of decreased Pi acquisition. The ZAT6 overexpression also resulted in altered root architecture of older plants, with consequent changes in Pi acquisition. These results indicate that ZAT6 regulates root development independent of the Pi status of the plant, thereby influencing Pi acquisition and homeostasis. In addition, the expression of several Pi starvation-responsive genes was decreased in ZAT6 overexpressing plants, thereby confirming the role of ZAT6 in regulating Pi homeostasis. This study thus indicates that ZAT6 is a repressor of primary root growth and regulates Pi homeostasis through the control of root architecture. To our knowledge, ZAT6 is the first cysteine-2/histidine-2 zinc finger transcription factor reported to regulate root development and nutrient stress responses.

The Dual-Targeted Purple Acid Phosphatase Isozyme AtPAP26 Is Essential for Efficient Acclimation of Arabidopsis to Nutritional Phosphate Deprivation

“…Disruption of genes involved in transcriptional reorganization or hormone-mediated responses to Pi starvation generally causes a shift in root structure architecture in addition to decreased primary root growth. For example, knockout of PSI transcription factors has been reported to reduce primary root growth with concomitant increases in lateral root and root hair development (Devaiah et al, 2007a(Devaiah et al, , 2007b. Similar results have been obtained with genes that mediate signal transduction in 2Pi Arabidopsis, such as phospholipase Dz1 and Dz2, in which a double knockout exhibited reduced phosphatidic acid levels and altered root structure architecture during Pi starvation (Li et al, 2006).…”

“…Pi deprivation induces temporal and tissue-specific expression of PSI APase isozymes (Haran et al, 2000;Wu et al, 2003;Zimmerman et al, 2004;Bozzo et al, 2006) and the concomitant downregulation of other APases (Misson et al, 2005). The transcription factors PHR1, WRKY75, and ZAT6 have been implicated in the control of Arabidopsis PSI APases (Rubio et al, 2001;Devaiah et al, 2007aDevaiah et al, , 2007b, while posttranscriptional mechanisms appear to be essential for the up-regulation of the purple APase (PAP) AtPAP26 during Pi stress (Veljanovski et al, 2006;Tran and Plaxton, 2008;Tran et al, 2010b). In contrast, Pi resupply to 2Pi plants rapidly represses PSI APase genes (del Pozo et al, 1999;Mü ller et al, 2004;Veljanovski et al, 2006) while inducing proteases that target PSI-secreted APases (Bozzo et al, 2004b).…”

Zinc-Finger Transcription Factor ZAT6 Positively Regulates Cadmium Tolerance through the Glutathione-Dependent Pathway in Arabidopsis

“…1E). Taken together, these results suggest that the Cd-tolerant phenotype of xcd2-D might be caused by the estradiol-induced expression of At5g04340, which was previously named as a known gene, ZAT6 (Devaiah et al, 2007).…”

“…ZAT6 expression has been shown to be regulated by phytohormones (Glazebrook et al, 2003). In addition, it was also found that ZAT6 is involved in regulating root development and low Pi stress responses (Devaiah et al, 2007). Recently, ZAT6 was shown to be involved in regulating responses of plants to pathogen infection, salt, drought, and freezing stresses (Shi et al, 2014).…”

Phosphite as phosphorus source to grain yield of common bean plants grown in soils under low or adequate phosphate availability

“…. The literature shows that some previous studies also found harmful effects of phosphite anion on plants grown under low phosphate availability, but no harmful effects have been reported when this anion was applied in plants grown under adequate phosphate availability (TICCONO et al, 2001;VARADARAJAN et al, 2002;LEE et al, 2005;SCHROETTER et al, 2006;DEVAIAH et al, 2007;THAO et al, 2008;MOOR et al, 2009;ÁVILA et al, 2011). However, most of these studies were based in Arabidopsis, vegetables, seedlings, citrus, and some cereals, but there is still little information on the effects of phosphite on leguminous plants, especially on grain yield of leguminous.…”