Annotations and Functional Analyses of the Rice Wrky Gene Superfamily Reveal Positive and Negative Regulators of Abscisic Acid Signaling in Aleurone Cells

Authors

Zhen Xie, University of Nevada, Las Vegas
Zhong-Lin Zhang, University of Nevada, Las Vegas
Xiaolu Zou, University of Nevada, Las Vegas
Jie Huang, University of Nevada, Las Vegas
Paul Ruas, University of Nevada, Las Vegas
Daniel Thompson, University of Nevada, Las VegasFollow
Qingxi J. Shen, University of Nevada Las Vegas, School of Life Sciences, MentorFollow

Document Type

Article

Publication Date

1-2005

Publication Title

Plant Physiology

Volume

137

Issue

1

First page number:

176

Last page number:

189

Abstract

The WRKY proteins are a superfamily of regulators that control diverse developmental and physiological processes. This family was believed to be plant specific until the recent identification of WRKY genes in nonphotosynthetic eukaryotes. We have undertaken a comprehensive computational analysis of the rice (Oryza sativa) genomic sequences and predicted the structures of 81 OsWRKYgenes, 48 of which are supported by full-length cDNA sequences. Eleven OsWRKY proteins contain two conserved WRKY domains, while the rest have only one. Phylogenetic analyses of the WRKY domain sequences provide support for the hypothesis that gene duplication of single- and two-domain WRKY genes, and loss of the WRKY domain, occurred in the evolutionary history of this gene family in rice. The phylogeny deduced from the WRKY domain peptide sequences is further supported by the position and phase of the intron in the regions encoding the WRKY domains. Analyses for chromosomal distributions reveal that 26% of the predicted OsWRKY genes are located on chromosome 1. Among the dozen genes tested, OsWRKY24, -51, -71, and -72 are induced by abscisic acid (ABA) in aleurone cells. Using a transient expression system, we have demonstrated that OsWRKY24 and -45 repress ABA induction of the HVA22 promoter-β-glucuronidase construct, while OsWRKY72 and -77 synergistically interact with ABA to activate this reporter construct. This study provides a solid base for functional genomics studies of this important superfamily of regulatory genes in monocotyledonous plants and reveals a novel function for WRKY genes, i.e. mediating plant responses to ABA.

Keywords

Abscisic Acid; Genes; Genetic regulation; Genetic transcription; Plant genetics; Proteins; Rice

Disciplines

Biomedical Engineering and Bioengineering | Genetics and Genomics | Mechanical Engineering | Plant Sciences

Language

English

Permissions

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Repository Citation

Xie, Z., Zhang, Z., Zou, X., Huang, J., Ruas, P., Thompson, D., Shen, Q. J. (2005). Annotations and Functional Analyses of the Rice Wrky Gene Superfamily Reveal Positive and Negative Regulators of Abscisic Acid Signaling in Aleurone Cells. Plant Physiology, 137(1), 176-189.