Os06g0308100
OsIBR5 is a putative MKP in rice[1].
Contents
Annotated Information
Function
OsIBR5 is a MKP which was induced by abiotic stresses and decreased tolerance to drought stress in transgenic tobacco plants. OsIBR5 participated in ABA regulating stomatal behavior and might function downstream of this pathway. OsIBR5 could interact with SIPK and WIPK, but not with NTF3 and MEK1[1]
GO assignment(s): GO:0004721,GO:0006470, GO:0008138
Mutation
wild-type and transgenic lines[1]:
- Different stomatal behavior was observed in OsIBR5-overexpressing tobacco plants in response to drought stress when compared with that of the WT plants.
- After 5 days of withholding water, stomata in WT plants were closed, but stomatal apertures in OsIBR5-overexpressing tobacco plants remained partially open.
- Drought-induced stomatal closure was inhibited in OsIBR5-overexpressing tobacco plants. The data indicated that the drought hypersensitivity phenotype of OsIBR5-overexpressing tobacco plants may be caused by reduced stomatal closure.
- Thus, drought and ABA-induced stomatal closure was significantly reduced in OsIBR5-overexpressing tobacco plants compared with controls.
Expression
- Expression of OsIBR5 was induced by PEG6000, abscisic acid (ABA) and hydrogen peroxide (H2O2). Overexpression of OsIBR5 in tobacco plants resulted in hypersensitivity to drought and H2O2 treatments. OsIBR5-overexpressing tobacco plants also exhibited oxidative stress hypersensitivity[1]. Expression of OsMKP1 was rapidly induced after wounding, whereas that of OsIBR5 was induced much later[2].
- The expression level of OsIBR5 increased approximately 4 times under PEG6000 treatment for 3 h and H2O2 treatment for 4 h, after which it decreased in both cases. Meanwhile, the transcription of OsIBR5 increased and reached the peak at 12 h with ABA treatment[1].
- OsIBR5 was found to be upregulated by drought and salt, downregulated by cold, with not obvious response to heat, gibberellin (GA), indoleacetic acis (IAA), kinetin (KT), naphthylacetic acid (NAA) and Zeatin. WIPK activity was impaired in OsIBR5-overexpressing tobacco plants[1].
Subcellular localization
When the construct was transiently expressed in rice protoplast, confocal microscopic examination of the transformed protoplasts revealed strong fluorescent signal in the cytoplasm and nucleus. Cells expressing the control GFP gene showed the typical cytoplasm and nuclear distribution of the GFP signal[1].
Evolution
Figure 1. Phylogenetic tree analysis of rice and Arabidopsis MKPs.(from reference [2]).
- OsIBR5 encodes one of the five potential MAPK phosphatases in the rice genome, which contains a conserved catalytic active site sequence motif (V/I) HCX2GXSRSX5A (Y/F)(L/I) M. By phylogenetic analysis of MKPs, OsIBR5 was grouped with AtIBR5, which is a
well-characterized MKP that modulated phytohormone signal transduction and support a link between auxin and ABA signaling pathways in Arabidopsis[1][3][4].
- As shown in Fig. 1, rice MKPs clearly correspond to MKPs in Arabidopsis. Therefore, Katou et al. designated the rice MKPs as OsMKP1, OsIBR5, OsDsPTP1, OsPHS1a and OsPHS1b, respectively (Fig. 1)[2].
- Katou et al. identified five putative MKPs in rice (Fig. 1), which is fewer than the number of MAPKs (17 members in rice)[2].
Knowledge Extension
- Mitogen-activated protein kinase (MAPK) cascades are universal signal transduction modules in eukaryotes, including yeasts, animals and plants. These protein phosphorylation cascades link extracellular stimuli to a wide range of cellular responses[5].
- In plants, MAPK cascades are involved in responses to various biotic and abiotic stresses, hormones, cell division and developmental processes. Completion of the Arabidopsis genome-sequencing project has revealed the existence of 20 MAPKs, 10 MAPK kinases and 60 MAPK kinase kinases[5].
- Ichimura et al. propose a simplified nomenclature for Arabidopsis MAPKs and MAPK kinases that might also serve as a basis for standard annotation of these gene families in all plants[5].
Labs working on this gene
- Guangdong Key Laboratory of Plant Resources, Key Laboratory of Gene Engineering of Ministry of Education and the State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, PR China
- National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602 Japan
- Program for Promotion of Basic Research Activities for Innovative Biosciences, Minato-ku, Tokyo, 105-0001 Japan
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Li Y, Feng D, Zhang D, et al. Rice MAPK phosphatase IBR5 negatively regulates drought stress tolerance in transgenic Nicotiana tabacum[J]. Plant Science, 2012, 188: 10-18.
- ↑ 2.0 2.1 2.2 2.3 Katou S, Kuroda K, Seo S, et al. A calmodulin-binding mitogen-activated protein kinase phosphatase is induced by wounding and regulates the activities of stress-related mitogen-activated protein kinases in rice[J]. Plant and cell physiology, 2007, 48(2): 332-344.
- ↑ Lee J S, Wang S, Sritubtim S, et al. Arabidopsis mitogen‐activated protein kinase MPK12 interacts with the MAPK phosphatase IBR5 and regulates auxin signaling[J]. The Plant Journal, 2009, 57(6): 975-985.
- ↑ Monroe-Augustus M, Zolman B K, Bartel B. IBR5, a dual-specificity phosphatase-like protein modulating auxin and abscisic acid responsiveness in Arabidopsis[J]. The Plant Cell Online, 2003, 15(12): 2979-2991.
- ↑ 5.0 5.1 5.2 Ichimura K, Shinozaki K, Tena G, et al. Mitogen-activated protein kinase cascades in plants: a new nomenclature[J]. Trends in plant science, 2002, 7(7): 301-308.
