Os02g0830200

Please input one-sentence summary here.

Annotated Information

Function

OsRR3 belongs to thirtten A-type response regulator (RR) genes in the rice genome[1]. The induction of OsRR genes by cytokinin even in the absence of de novo protein synthesis qualifies them to be primary cytokinin response genes[2]. OsRR3 and OsRR5 mainly act as negative regulators of cytokinin signaling, as indicated by the reduced sensitivity of OsRR3 and OsRR5 overexpressors to exogenous cytokinins[3].

Expression

Three A-type RR genes(OsRR4, OsRR9and OsRR10 for O. sativa RR) showed cytokinin-induced expression, and three (OsRR8, OsRR12andOsRR13) showed expression in flower. The transcripts of OsRR genes could be detected by real-time PCR in all organs of the light- and dark-grown rice seedlings/plants, although there were quantitative differences. The steady-state transcript levels of most of the OsRR genes increased rapidly (within 15 min) on exogenous cytokinin application even in the presence of cycloheximide. Moreover, the expression of the OsRR6 gene was enhanced in rice seedlings exposed to salinity, dehydration and low temperature stress.

Evolution

Phylogenetic relationship among type-A response regulator proteins from rice (OsRR), maize (ZmRR), and Arabidopsis (ARR). The unrooted tree was generated using ClustalX program by neighbor-joining method and visualized by Treeview. Scale bar represents 0.1 amino acid substitution per site.

Labs working on this gene

Please input related labs here. 1.Rice seedlings overexpressing OsRR3 and OsRR5 are less sensitive to cytokinin inhibition of root elongation and lateral root formation[3].

Analysis of root elongation and lateral root formation during overexpression of OsRR3 and OsRR5 in transgenic rice and ZH11 (CK) in the presence of exogenous hormones. A., B., C.Seeds were grown on plates supplemented with the specified concentrations of BA, 2,4-D, ABA, or DMSO control, under a 16-h photoperiod at 23°C. Error bars represent SE (N = 30). D. Seeds were grown on plates supplemented with the specified concentrations of BA control under a 16-h photoperiod at 23°C. The total number of lateral roots was determined at 15 days. Error bars represent SE (N= 30). E.Phenotypes of roots for 16-day-old seedlings of (from left to right) ZH11, pACT1:OsRR3, and pACT1:OsRR5 treated with 0.5 μM BA under a 16-h photoperiod.

2.Callus formation of pACT1:OsRR3 and pACT1:OsRR5 is less sensitive to cytokinin[3].

With increasing cytokinin:auxin ratios, larger calli were formed and green shoots were longer (Figure 4A). Both pACT1:OsRR3 and pACT1:OsRR5 formed smaller calli and shorter shoots with concentrations of hormones that were able to induce ZH11 calli (Figure 4B and C). The decrease in sensitivity to hormones of pACT1:OsRR3 and pACT1:OsRR5 in callus and shoot formation showed that both OsRR3 and OsRR5 act as negative regulators of the cytokinin-signaling system.

References

Please input cited references here. 1. Yukihiro Ito;Nori Kurata

 Identification and characterization of cytokinin-signalling gene families in rice
 Gene, 2006, 382(1): 57-65

2. Mukesh Jain;Akhilesh K Tyagi;Jitendra P Khurana

 Molecular characterization and differential expression of cytokinin-responsive type-A response regulators in rice (Oryza sativa)
 BMC Plant Biology, 2006, 6: 1

3. X. Cheng;H. Jiang;J. Zhang;Y. Qian;S. Zhu;B. Cheng

 Overexpression of type-A rice response regulators, OsRR3 and OsRR5, results in lower sensitivity to cytokinins
 Genetics and Molecular Research, 2010, 9(1): 348-359