© 2007 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
Maize nitrilases have a dual role in auxin homeostasis and β-cyanoalanine hydrolysis
1Lehrstuhl für Genetik, Technische Universität München, Am Hochanger 8, D-85350 Freising, Germany
2Lehrstuhl für Pflanzenphysiologie, Ruhr-Universität, Universitätsstrasse 150, D-44801 Bochum, Germany
3Pioneer Hi-Bred International, 7300 NW 62nd Avenue, Johnston, IA 50131-1004, USA
To whom correspondence should be addressed. E-mail: egl{at}wzw.tum.de
The auxin indole-3-acetic acid (IAA), which is essential for plant growth and development, is suggested to be synthesized via several redundant pathways. In maize (Zea mays), the nitrilase ZmNIT2 is expressed in auxin-synthesizing tissues and efficiently hydrolyses indole-3-acetonitrile to IAA. Zmnit2 transposon insertion mutants were compromised in root growth in young seedlings and sensitivity to indole-3-acetonitrile, and accumulated lower quantities of IAA conjugates in kernels and root tips, suggesting a substantial contribution of ZmNIT2 to total IAA biosynthesis in maize. An additional enzymatic function, turnover of β-cyanoalanine, is acquired when ZmNIT2 forms heteromers with the homologue ZmNIT1. In plants carrying an insertion mutation in either nitrilase gene this activity was strongly reduced. A dual role for ZmNIT2 in auxin biosynthesis and in cyanide detoxification as a heteromer with ZmNIT1 is therefore proposed.
Key words: Auxin, cyanoalanine, IAA, IAN, maize, nitrilase
* Present address: Department of Molecular Biology, BK21 Graduate Program for RNA Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin-si, Gyeonggi-do 448-701, South-Korea.
Received 18 September 2007; Revised 16 October 2007 Accepted 17 October 2007
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Bottcher, L. Westphal, C. Schmotz, E. Prade, D. Scheel, and E. Glawischnig The Multifunctional Enzyme CYP71B15 (PHYTOALEXIN DEFICIENT3) Converts Cysteine-Indole-3-Acetonitrile to Camalexin in the Indole-3-Acetonitrile Metabolic Network of Arabidopsis thaliana PLANT CELL, June 1, 2009; 21(6): 1830 - 1845. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Sanchez-Perez, K. Jorgensen, C. E. Olsen, F. Dicenta, and B. L. Moller Bitterness in Almonds Plant Physiology, March 1, 2008; 146(3): 1040 - 1052. [Abstract] [Full Text] [PDF]
|
|