Ballachanda, Devaiah , Nagarajan, Vinay , Raghothama, Kashchandra G .
Role of ZAT6 in Phosphate Stress Response.
Phosphate (Pi) is one of the least available plant nutrients in soil. Information regarding transcriptional factors regulating adaptive mechanisms triggered by Pi starvation can therefore help in developing Pi-use-efficient plants. This study has characterized Zinc finger of Arabidopsis thaliana 6 (ZAT6), a C2H2 zinc finger transcription factor that is responsive to Pi stress. ZAT6 is induced during Pi starvation and localized to the nucleus irrespective of the Pi status of the plant. Suppression of ZAT6 through RNAi resulted in non-germinating seeds supporting an earlier contention that it may be involved in regulating ovule development. On the other hand, over-expression of ZAT6 resulted in retarded seedling growth, increased anthocyanin content and acid phosphatase (ACP) activity during early stages of seedling development. Further analysis revealed that young ZAT6 over-expressing seedlings had lower Pi uptake and accumulation. However, the ZAT6 over-expressing seedlings recovered through increased ACP activity, a well-documented Pi stress adaptive mechanism. This indicates that ZAT6 plays a pivotal role in regulating Pi homeostasis during early development of seedlings. As the ZAT6 over-expressing seedlings grew older, they had significantly decreased primary root length and lateral root number with longer lateral roots. These alterations in the root architecture resulted in a larger root to shoot ratio in ZAT6 over-expressing seedlings. The Pi uptake in these older seedlings was consequently increased under both Pi sufficient and deficient conditions leading to increased Pi accumulation. Together, these results indicate that ZAT6 is a repressor of primary root growth and regulates Pi homeostasis through the control of root architecture.
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1 - Purdue University, Department of Horticulture and Landscape Architecture, 625 Agriculture Mall Drive, West Lafayette, IN, 47907, USA
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM