|
|
||||||||
|
First published online March 2, 2007; 10.1104/pp.107.095752 Plant Physiology 143:1929-1942 (2007) © 2007 American Society of Plant Biologists An Unusual Posttranscriptional Processing in Two Betaine Aldehyde Dehydrogenase Loci of Cereal Crops Directed by Short, Direct Repeats in Response to Stress Conditions1Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science (X.N., W.Z., W.H., S.W., J.L., Z.T., D.L., Y.L.), and State Key Laboratory of Hydraulics and Mountain River Engineering (Y.L.), Sichuan University, Chengdu 610064, China; Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Fudan University, Shanghai 200433, China (B.-R.L., Y.W.); and Institute of Crop Research, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China (G.R.)
Various abilities to synthesize and accumulate glycine betaine (GB) are crucial for angiosperms to develop salt and drought tolerances. In higher plants, GB is synthesized by a two-step oxidation of choline via an intermediate form of betaine aldehyde, and catalyzed by choline monooxygenase and betaine aldehyde dehydrogenase (BADH). In this study, numerous truncated and/or recombinant transcripts of two BADH homologs resulting from an unusual posttranscriptional processing were detected in rice (Oryza sativa) and other cereal crops, including maize (Zea mays), wheat (Triticum aestivum), and barley (Hordeum vulgare). The observed events took place at the 5' exonic region, and led to the insertion of exogenous gene sequences and a variety of deletions that resulted in the removal of translation initiation codon, loss of functional domain, and frame-shifts with premature termination by introducing stop codon. By contrast, the BADH transcripts from dicotyledonous species, such as spinach (Spinacia oleracea), Arabidopsis (Arabidopsis thaliana), and tomato (Solanum lycopersicum), had correctly processed mRNA. This suggests the differentiation of posttranscriptional processing in BADH genes potentially contributes to the variation of GB-synthesizing capacities among various plant species. In addition, comprehensive sequence analyses demonstrated that extensive sequence similarities (named as short, direct repeats) are of paired presence surrounding the junctions of both the deletion and/or insertion sites in the unusual BADH transcripts. The site selection for the deletion/insertion was altered in response to the stress conditions. This indicates that the sequence elements of short, direct repeats are probably required for the recognition of the deletion/insertion sites.
1 This work was supported by the Chinese Ministry of Science and Technology (973 Program, grant no. 2006CB100205), by the local government of Sichuan Province (application basis project, grant no. 2006Z050039), and by Sichuan University (985 youth talent program, grant no. 0082204127106). 2 These authors contributed equally to the paper. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Yongsheng Liu (liuyongsheng1122{at}yahoo.com.cn). www.plantphysiol.org/cgi/doi/10.1104/pp.107.095752 * Corresponding author; e-mail liuyongsheng1122{at}yahoo.com.cn; fax 862885415300. Received January 10, 2007; accepted February 25, 2007; published March 2, 2007. This article has been cited by other articles:
|
|||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|