OsWRKY11 is a member of WRKY TF superfamily, which relates to abiotic stress.
- An OsWRKY11 gene, which encodes a transcription factor with the WRKY domain, was identified as one of the genes that was induced by both heat shock and drought stresses in seedlings of rice. OsWRKY11 plays a role in heat and drought stress response and tolerance, and might be useful for improvement of stress tolerance. Introduction of HSP101 promoter::OsWRKY11 might have caused some deleterious effects on plant growth.
- OsWRKY11 induced activation of the genes(Os07g0209100, Os07g0687900) involved in raffinose synthesis and the accumulated raffinose played an important role in the desiccation tolerance of the OsWRKY11-overexpressed plants.
- It is expected that OsWRKY11 binds to the W box sequence and activates the RS gene expression. It is also possible that OsWRKY11 binds to some other genes that activate the RS genes indirectly.
- Wang et al. designated lla mutant gene OsWRKY11. Schematic diagram of T-DNA inserted locus and structures of OsWRKY11 gene were shown in Fig. 1. T-DNA insertion locus was located at the region of two overlapping PAC clones, AP002744 and AP002839 in rice Chromosome 1.
- the flanking sequence was highly homologous to two overlapping PAC clones, AC002744 and AP002839 respectively, in rice chromosome 1. The coding sequence was deduced by rice full-length cDNA (AK10874 and AK108745). T-DNA was inserted in the position of 5′ upstream of a putative WRKY transcript factor gene.
- OsWRKY11 gene would probably regulate culm elongation, leaf development and flowering time, which probably provide additional evidence that WRKY gene participated in plant developmental processes.
OsWRKY11.1 and OsWRKY11.2
- The dlf1 mutation was caused by a T-DNA insertion and the cloned Dlf1 gene was found to encode a WRKY transcription factor (OsWRKY11). Accumulation of Dlf1 mRNA was observed in most tissues, and two splicing forms of Dlf1 cDNAs were obtained (OsWRKY11.1 and OsWRKY11.2). These two proteins showed transactivation activity in yeast cells.
- Enhanced expression of OsWRKY11.2 or its 59 truncated gene showed similar phenotypes to the dlf1 mutant, suggesting that it might function as a negative regulator.
- OsWRKY11.1 encoded the deduced 379-aa Dlf1 protein and the shorter sequence (assigned as OsWRKY11.2) contained a 161 bp deletion in the third exon causing a premature stop of translation. The deduced amino acid sequence of OsWRKY11.2 encodes a protein of 270 residues, which still contains the WRKY domain.
- The OsWRKY11.2 protein also contains the sequence of nuclear localization signal.
GO assignment(s): GO:0003700,GO:0005634, GO:0043565, GO:0045449
- Four independent transgenic lines:
- A transgenic line:
- #g8: contained HSP101 promoter::GUS, was used as a negative control.
- The transgenic lines, #ox2 and #ox3, were identified to have a single copy of T-DNA, and #ox4 contained two copies and #ox5 carried four copies.
- Three types of phenotypes were observed: dwarf with bent leaves, normal plant length with bent leaves and normal plant length with normal leaves.
- Most of the OsWRKY11 transgenic plants show the phenotype of normal plant length with bent leaves; plant length was more than 94 cm. In contrast, #ox4 showed dwarf phenotype; the plant length was less than 85 cm, and the WT plant had a plant length of 110–128 cm. Nontransgenic plants segregating from each primary transformant showed a phenotype of normal plant length with normal leaves.
- Plant length of #ox3 was significantly shorter than that of #ox2, #g8, and WT. Under normal growth conditions, the seed set percentage was 36.7 ± 5.8 for #ox2 and 98.0 ± 0.8 for #ox3.
- Ubi:W11.1 and Ubi:W11.2:
- Most of the OsWRKY11.1 transgenic plants did not show morphological differences to controls. Nevertheless, two RNAi lines with decrease in OsWRKY11 expression showed early flowering under LD conditions. On the other hand, the accumulation of total OsWRKY11 mRNA was extremely high in the lines harboring the Ubi:W11.2 construct, which is 109 aa shorter than Ubi:W11.1 in the C-terminus.
- Interestingly, most of the Ubi:W11.2 and Ubi:W11.2 transgenic plants exhibited dwarf and late flowering phenotypes, similar to the dlf1 mutant. Likely, OsWRKY11.2 retained the transactivation activity and the sequence of nuclear localization signal, which suggesting that the high level of OsWRKY11.2, or its Nterminus truncated protein might function as a negative regulator.
- OsWRKY11 cDNA was fused to the promoter of HSP101 of rice and introduced into a rice cultivar Sasanishiki. Overexpression of OsWRKY11 was induced by heat treatment'. After heat pretreatment, the transgenic lines showed significant heat and drought tolerance, as indicated by the slower leaf-wilting and less impaired survival rate of green parts of plants. They also showed significant desiccation tolerance, as indicated by the slower water loss in detached leaves.
- The relative OsWRKY11 expression level was also investigated using real-time quantitative RT-PCR. The value indicates the relative expression level compared to that of tubulin. The relative OsWRKY11 expression level of #ox2 and #ox3 with no-heat treatment(control condition) was the same as that of WT. In contrast, the values were 3.7 times higher in #ox2 and 3.0 times higher in #ox3 than in WT after the heat pretreatment, which demonstrating that overexpression of WRKY11 was induced by heat treatment, but it was not detectable under unstressed normal conditions.
- Prolonged heat and drought treatment caused all the WT plants to die, while the OsWRKY11 transgenic lines #ox2 and #ox3 survived, which demonstrating that the OsWRKY11 transgenic lines #ox2 and #ox3 gained significant heat and drought tolerance.
- It is considered that the heat pretreatment induced the expression of the introduced OsWRKY11 in addition to induction of endogenous OsWRKY11. Crosstolerance of heat and drought stresses was
implicated even in WT plants.
- Raffinose was shown to accumulate at a significantly higher level in the transgenic plants overexpressing OsWRKY11. Microarray analysis of gene expression profile indicated that the gene expression of Os07g0209100 encoding raffinose synthase and that of Os07g0687900 encoding galactinol synthase were upregulated.
- Interestingly,OsWRKY11(group III) was hormone specific (ABA and GA3), root tissue specific, and IR77298-14-1-2-B-10 specific underboth WDTs, and its expression level was approximately five-fold higher in IR77298-14-1-2-B-10 than in IR77298-14-1-2-B-13 and IR64 with mild stress. However, OsWRKY11 exhibitedlower expression levels in the root of Minghui 63.
- The OsWRKY11 gene was expressed specifically in IR77298-14-1-2-B-10 under both WDTs in the root and under mild stress in the panicle but was not differentially expressed under normal growth con-ditions. Under both WDTs, several genes that were up-regulatedin both the root and panicle overlapped in IR77298-14-1-2-B-10and IR77298-14-1-2-B-13.
- The OsWRKY11 gene from the WRKY family was located in the QTL region, and this gene was up-regulated in the tolerant line compared to the control line. OsWRKY11 was induced in the root and panicle in the tolerant IR77298-14-1-2-B-10 line under both WDTs and following ABA treatment.
- DgWRKY1 was clustered into the II-c subgroup, and was most closely related to OsWRKY11. The DgWRKY1 was structurally similar to OsWRKY11.
- The sequence analysis for 15 M. grisea-inducible OsWRKYs indicated that 5, OsWRKY30, OsWRKY70, OsWRKY82, OsWRKY84, and OsWRKY85, belong to WRKY group I which contains two WRKY domains(Fig. 2)。 Among the WRKY group IIc family, four M. grisea-inducible WRKYs were identified, OsWRKY7, OsWRKY10, OsWRKY11, and OsWRKY67(Fig. 2). The remaining M. grisea-inducible WRKYs were included in four different groups: IIa (OsWRKY62 and OsWRKY76), IIb (OsWRKY32), IId (OsWRKY83), and III (OsWRKY45 and OsWRKY64) (Fig. 2).
- The WRKY TF superfamily consists of 74 and 109 members in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa), respectively.
- The current data point toward the existence of a WRKY-smRNA interactome, where on the one hand, pathogen attack triggers the expression of WRKY genes that regulate cellular smRNA populations, and on the other hand, several differentially regulated smRNAs modulateWRKY TF levels by targeting their transcripts (Fig. 3).
- During pathogen attack, smRNA-generating loci may be under the control of WRKY TFs; at the same time, WRKY abundance may be regulated by smRNAs. RdR, RNA-directed RNA polymerase(Fig. 3).
Labs working on this gene
- Laboratory of Environmental Biotechnology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
- Plant Genome Research Unit Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8602, Japan
- Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku 338-8570, Japan
- Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila 1301, Philippines
- Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Wu X, Shiroto Y, Kishitani S, et al. Enhanced heat and drought tolerance in transgenic rice seedlings overexpressing OsWRKY11 under the control of HSP101 promoter[J]. Plant cell reports, 2009, 28(1): 21-30.
- ↑ 2.0 2.1 2.2 Wu X, Kishitani S, Ito Y, et al. Accumulation of raffinose in rice seedlings overexpressing OsWRKY11 in relation to desiccation tolerance[J]. Plant biotechnology, 2009, 26(4): 431-434.
- ↑ 3.0 3.1 3.2 3.3 3.4 Wang D, Zhang H, Hu G, et al. Genetic analysis and identification of a large leaf angles (lla) mutant in rice[J]. Chinese Science Bulletin, 2005, 50(5): 492-494.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Cai Y, Chen X, Xie K, et al. Dlf1, a WRKY Transcription Factor, Is Involved in the Control of Flowering Time and Plant Height in Rice[J]. PloS one, 2014, 9(7): e102529.
- ↑ 5.0 5.1 5.2 Nuruzzaman M, Sharoni A M, Satoh K, et al. Comparative transcriptome profiles of the WRKY gene family under control, hormone-treated, and drought conditions in near-isogenic rice lines reveal differential, tissue specific gene activation[J]. Journal of plant physiology, 2014, 171(1): 2-13
- ↑ Liu Q L, Xu K D, Pan Y Z, et al. Functional analysis of a novel chrysanthemum WRKY transcription factor gene involved in salt tolerance[J]. Plant Molecular Biology Reporter, 2014, 32(1): 282-289.
- ↑ 7.0 7.1 7.2 Ryu H S, Han M, Lee S K, et al. A comprehensive expression analysis of the WRKY gene superfamily in rice plants during defense response[J]. Plant cell reports, 2006, 25(8): 836-847.
- ↑ 8.0 8.1 8.2 8.3 Pandey S P, Somssich I E. The role of WRKY transcription factors in plant immunity[J]. Plant physiology, 2009, 150(4): 1648-1655.
- ↑ Eulgem T, Somssich I E. Networks of WRKY transcription factors in defense signaling[J]. Current opinion in plant biology, 2007, 10(4): 366-371.
- ↑ Ross C A, Liu Y, Shen Q J. The WRKY gene family in rice (Oryza sativa)[J]. Journal of Integrative Plant Biology, 2007, 49(6): 827-842.