Plant and Cell Physiology Advance Access originally published online on February 9, 2007
Plant and Cell Physiology 2007 48(3):523-539; doi:10.1093/pcp/pcm022
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Overexpression of a Type-A Response Regulator Alters Rice Morphology and Cytokinin Metabolism
RIKEN Plant Science Center, 1-7-22, Suehiro, Tsurumi, Yokohama, 230-0045 Japan
*Corresponding author: E-mail, sakaki{at}riken.jp; Fax, +81-45-503-9609
 |
Abstract |
|---|
Genome-wide analyses of rice (Oryza sativa L.) cytokinin (CK)-responsive genes using the Affymetrix GeneChip® rice genome array were conducted to define the spectrum of genes subject to regulation by CK in monocotyledonous plants. Application of trans-zeatin modulated the expression of a wide variety of genes including those involved in hormone signaling and metabolism, transcriptional regulation, macronutrient transport and protein synthesis. To understand further the function of CK in rice plants, we examined the effects of in planta manipulation of a putative CK signaling factor on morphology, CK metabolism and expression of CK-responsive genes. Overexpression of the CK-inducible type-A response regulator OsRR6 abolished shoot regeneration, suggesting that OsRR6 acts as a negative regulator of CK signaling. Transgenic lines overexpressing OsRR6 (OsRR6-ox) had dwarf phenotypes with poorly developed root systems and panicles. Increased content of trans-zeatin-type CKs in OsRR6-ox lines indicates that homeostatic control of CK levels is regulated by OsRR6 signaling. Expression of genes encoding CK oxidase/dehydrogenase decreased in OsRR6-ox plants, possibly accounting for elevated CK levels in transgenic lines. Expression of a number of stress response genes was also altered in OsRR6-ox plants.
Keywords: Cytokinin - Gene chip - Microarray - Oryza sativa - Response regulator
Abbreviations: ACC, 1-aminocyclopropane-1-carboxylate; AMT, ammonium transporter; AP2/EREBP, APETALA2/ethylene-responsive element binding protein; ARF, auxin response factor; AUX/IAA, auxin/indole-3-acetic acid; bHLH, basic helix–loop–helix; CaMV, cauliflower mosaic virus; CK, cytokinin; CKX, CK oxidase/dehydrogenase; DMSO, dimethylsulfoxide; GA, gibberellin; GFP, green fluorescent protein; HK, His protein kinase; HP, His-containing phosphotransfer protein; IPT, adenosine phosphate-isopentenyltransferase; PHT, phosphate transporter; PUP, purine permease; RR, response regulator; RT–PCR, reverse transcription–PCR; SULTR, sulfate transporter; tZ, trans-zeatin; tZR, tZ riboside; tZRMP, tZR 5'-monophosphate
(Received December 3, 2006; Accepted February 4, 2007)
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Yuan, D. Chen, Y. Ren, X. Zhang, and J. Zhao Characteristic and Expression Analysis of a Metallothionein Gene, OsMT2b, Down-Regulated by Cytokinin Suggests Functions in Root Development and Seed Embryo Germination of Rice Plant Physiology, April 1, 2008; 146(4): 1637 - 1650. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Hirose, K. Takei, T. Kuroha, T. Kamada-Nobusada, H. Hayashi, and H. Sakakibara Regulation of cytokinin biosynthesis, compartmentalization and translocation J. Exp. Bot., January 1, 2008; 59(1): 75 - 83. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P.C. To, J. Deruere, B. B. Maxwell, V. F. Morris, C. E. Hutchison, F. J. Ferreira, G. E. Schaller, and J. J. Kieber Cytokinin Regulates Type-A Arabidopsis Response Regulator Activity and Protein Stability via Two-Component Phosphorelay PLANT CELL, December 1, 2007; 19(12): 3901 - 3914. [Abstract] [Full Text] [PDF]
|
|