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Annotated Information


Schematic diagrams of conserved motifs found in the OsWRKY51 peptide sequences.WRKY motif; zinc finger, zinc finger motif; NLS, putative nuclear localization motif; HARF, conserved motif only found in a subgroup of WRKY proteins; LXXLL, putative co-activator motif; Lx, putative active repressor motif with the LXLXLX consensus sequences; SUMO, putative sumoylation motif; LZ, putative Leu-zipper motif.

The gene symbol is OsWRKY51, and NCBI GeneBank accession number is BK005053, RAP-DB is Os04g0287400 and MSU is LOC_Os04g21950. OsWRKY51 belongs to the WRKY family which encodes transcription factors that are involved in the regulation of various biological processes. OsWRKY51 encodes a group II WRKY protein(but Zhang Yj et al classified it as group Ic and Wu Kun-Lu et al group Ia ) contains one WRKY domain initially defined by a nearly 60 amino acid long motif with a C2H2-type zinc finger motif. Only the C-terminal domain of this motif active in DNA binding. The pattern of potential zinc ligands(C-X4-5-C-X22-23-H-X1-H)is unique among all described zinc-finger-like motifs. Nevertheless, experimental evidence has shown OsWRKY51 can bind sequence specifically to various W box elements (T)(T)TGAC(C/T) containning the invariant TGAC core which is essential for function and WRKY binding. The figure OsWRKY51 CONSTYUCT shows the concrete motifs of OsWRKY51.


OsWRKY51 and 103 share the identical WRKY domains and have a high identity of the corresponding coding nucleotide sequences. These highly similar genes may represent newly duplicated paralogues.


Proposed roles for OsWRKY51 and OsWRKY71 in modulating the cross-talk of giberellin (GA) and abscisic acid (ABA)signaling. Filled ovals represent OsWRKY51 and OsWRKY71; the open oval represents GAMYB. Open squares represent cis-acting elements in the low pI α-amylase promoter: W, W-box; GARE, GA-responsive element. Arrows represent induction and T-bars denote repression.
The dosage experiment was carried out with a constant amount of the reporter construct (Amy32b-GUS) and varied amounts of the effector construct(s) in the presence of 1 lM GA3 for 24 h. The relative amount of effector construct is indicated as a percentage compared to the amount of reporter.

OsWRKY51 is identified as ABA-inducible and gibberellin (GA)-repressible rice WRKY gene, although OsWRKY51 itself does not bind to the Amy32b promoter in vitro.It interacts with OsWRKY71 and enhances the binding affinity of OsWRKY71 to W boxes in the Amy32b promoter. Titration experiments suggest that the ratio of repressors (such as OsWRKY51 and OsWRKY71) to the activator (e.g. OsGAMYB) seems to determine the expression level of the Amy32b promoter. These data demonstrate the synergistic interaction of ABA-inducible WRKY genes in regulating GAMYB-mediated GA signaling in aleurone cells, thereby establishing a novel mechanism for ABA and GA signaling cross talk.A model is proposed for the role of OsWRKY51 and OsWRKY71 in mediating the cross-talk of GA and ABA signaling. The OsWRKY51/OsWRKY71 repressors form a heterotetramer to bind the W-boxes, thus exerting an antagonistic effect against GA induction of Amy32b. In contrast, GA induces GAMYB, but suppresses OsWRKY51 and OsWRKY71. The ratio of OsWRKY51/OsWRKY71 to GAMYB is low, so that GAMYB competes against the inhibitory effect of OsWRKY51 and OsWRKY71, leading to a high level of α-amylase gene expression. Obviously, this is an over-simplified model because it does not consider other activators, such as OsDOF3, RAMY, and OsMYBS1/OsMYBS2, as well as other repressors, such as KGM (for kinase associated with GAMYB; Woodger et al. 2003) and HRT(for Hordeum repressor of transcription; Raventós et al. 1998).Nevertheless, this model gives us new insights about how multiple transcription factors coordinate to fine tune Amy32b expression triggered by different signals. To study the combinatory effect of these two repressors, dosage experiments were performed for OsWRKY51 alone, OsWRKY71 alone, and OsWRKY51 with OsWRKY71(resulta). The results indicated that co-expression of UBI-OsWRKY51 at the 1% (effector/reporter) ratio had no suppression activity on the GA induction of Amy32b-GUS. Co-expression of 1% UBI-OsWRKY71 suppressed the GA induction of Amy32b-GUS to 91% of the control. Interestingly, co-expression of 1% UBI-OsWRKY51 plus 1% UBI-OsWRKY71 strongly reduced the GA induction of Amy32b-GUS to 25% of the control (resultb). It is important to point out that this increased effect is unlikely to be due to twice as much effector DNA in the mixture. In fact, the reporter expression level resulting from 1% UBI-OsWRKY51 plus 1%UBI-OsWRKY71 was even lower than that for 2.5%, 5%, 7.5% or 10% UBI-OsWRKY51 or UBI-OsWRKY71 alone. These results suggest that the effect of OsWRKY51 and OsWRKY71 is not additive, but they synergistically act to suppress the GA induction of Amy32b.


Expression patterns of OsWRKY51 gene in rice aleurone cells
OsWRKY51 is expressed in rice aleurone cells,and is induced the expression by abscisic acid.
The abundant transcripts of OsWRKY51 were enhanced upon ABA treatment. Furthermore,the mRNA levels 
of OsWRKY51 were down regulated in response to exogenous GA3 treatments at 24-and 48-h time points.


Group Ia proteins (red); group Ib proteins (purple); group II proteins(black); group III proteins (green); group IVa proteins (yellow); group IVb proteins (blue)
Deduced evolutionary framework of the OsWRKY gene family
Unrooted phylogenetic tree of the WRKY domains.
Rice WRKY gene (OsWRKY) with suffix -N or -C indicates the N-terminal (NTWD) or the C-terminal WRKY domain (CTWD) in one gene.

The majority rule consensus phylogenetic unrooted tree was reconstructed based on the WRKY domain peptide sequences by the MrBayes 3.0 program(figure: tree). An evolutionary framework of the OsWRKY gene family was deduced based on the phylogenetic analysis and the features of the WRKY domain(figure: OsWRKY gene family). Rectangles designate the N-orC-terminal WRKY domains with a C2H2 or C2HC type of zinc finger motif. Some group II WRKY genes are likely to be evolved from group Ia WRKY genes by losing either the N-or the C-terminal WRKY domain. The replacement of the conserved His residue with a Cys residue in the zinc finger motif might result in the evolution of group IIIWRKY genes. Group Ib WRKY genes might be evolved from group III WRKY genes by duplication of the CHC-type WRKY domain. But Zhang Yj reconstructed the tree from the amino acid sequences using the neighbor-joining program from Phylip 3.57, and classified OsWRKY51 into group Ic. (figure:classify). However, according to Wu Kunlu, OsWRKY51 is classified into group Ia(figure: otherclassify).

Labs working on this gene

1. Corresponding author: Qingxi J.Shen. Department of Plant and Microbial Biology,University of California, Berkeley, CA 94720 and Plant Gene Expression Center, U.S. Department of Agriculture, Albany, CA 94710. 2. Corresponding author: Duk-JuHwang. Bio-Crop Development Division, National Academy of Agricultural Science, Rural Development Administration, Suwon440-707, Republic of Korea. 3. Corresponding author: Yuanji Zhang. Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73402, USA. 4. Corresponding author: Zejian Guo. Biotechnology, China Agricultural University, Beijing 100094, PR China.


1. Seon-Hee Hwang;Se Won Yie;Duk-Ju Hwang Heterologous expression of OsWRKY6 gene in Arabidopsis activates the expression of defense related genes and enhances resistance to pathogens. Plant Science, 2011, 181(3): 316-323. 2. Christian A. Ross;Yue Liu;Qingxi J. Shen The WRKY Gene Family in Rice (Oryza sativa) Journal of Integrative Plant Biology, 2007, 49(6): 827-842. 3. Zhen Xie;Zhong-Lin Zhang;Xiaolu Zou;Guangxiao Yang;Setsuko Komatsu;Qingxi J. Shen Interactions of two abscisic-acid induced WRKY genes in repressing gibberellin signaling in aleurone cells. The Plant Journal, 2006, 46(2): 231-242. 4. Zhen Xie;Zhong-Lin Zhang;Xiaolu Zou;Jie Huang;Paul Ruas;Daniel Thompson;Qingxi J. Shen. Annotations and Functional Analyses of the Rice WRKY Gene Superfamily Reveal Positive and Negative Regulators of Abscisic Acid Signaling in Aleurone Cells Plant Physiology, 2005, 137(1): 176-189. 5. Zhong-Lin Zhang;Zhen Xie;Xiaolu Zou;Jose Casaretto;Tuan-hua David Ho and Qingxi J. Shen. A Rice WRKY Gene Encodes a Transcriptional Repressor of the Gibberellin Signaling Pathway in Aleurone Cells. Plant Physiology, 2004, 134(4): 1500-1513. 6. Kun-Lu Wu, Ze-Jian Guo, Hai-Hua Wang, et al. The WRKY Family of Transcription Factors in Rice and Arabidopsis and Their Origins. DNA Res, 2005, 12(1):9-26. 7.Parinita Agarwal, M.P.Reddy, Jitendra Chikara. WRKY: its structure, evolutionary relationship, DNA-binding selectivity, role in stress tolerance and development of plants. Mol Biol Rep, 2011, 38:3883-3896.

Structured Information