Os01g0711600

The rice Os01g0711600 gene expresses protein called OsRTH1, which functionally related with ethylene insensitivity in rice and other species.

Annotated Information

Function

Overexpression of Arabidopsis Reversion-To-ethylene Sensitivity1 (RTE1) results in whole-plant ethylene insensitivity dependent on the ethylene receptor gene Ethylene Response1 (ETR1). There're three types of rice RTE1 homologues (OsRTH genes), results from a cross-species complementation test in Arabidopsis showed that OsRTH1 overexpression complemented the rte1-2 loss-of-function mutation and conferred whole-plant ethylene insensitivity in an ETR1-dependent manner. In contrast, OsRTH2 and OsRTH3 overexpression did not complement rte1-2 or confer ethylene insensitivity. In rice, OsRTH1 overexpression substantially prevented ethylene-induced alterations in growth and development, including leaf senescence, seedling leaf elongation and development, coleoptile elongation or curvature, and adventitious root development. Results of subcellular localizations of OsRTHs, each fused with the green fluorescent protein, in onion epidermal cells suggested that the three OsRTHs were predominantly localized to the Golgi. OsRTH1 may be an RTE1 orthologue of rice and modulate rice ethylene responses.

Expression

1. Cross-species complementation test of OsRTHs in Arabidopsis(fig.1).

Functional analyses of plant RTHs in Arabidopsis. The seedling triple-response phenotype of ethylene-grown wild type (Col-0) and 35S:OsRTH1 transformation lines (A), (ETR1)4LOF and a mutant expressing 35S:OsRTH1 (B), etr1-7 and a mutant expressing 35S:OsRTH1 (C), and etr1-2 rte1-2 and a mutant expressing 35S:OsRTH1 (D). (E) The seedling triple-response phenotype of the wild type (Col-0) expressing 35S:OsRTH2 and 35S:OsRTH3. (F) Seedling triple-response phenotype of etr1-2 rte1-2 expressing 35S:OsRTH2 and OsRTH3. Leaf senescence phenotype of the wild type (Col-0) (G) and ethylene-insensitive etr1-2 (H); phenotype of wild type (Col-0), (ETR1)4LOF (J), etr1-2 rte1-2 (K), and etr1-7 (L) expressing 35S:OsRTH1. Air and ethylene indicate the phenotype of the same plants before and after the treatment, respectively. Chlorophyll a measurement (M) and SAG12 expression (N) of the wild type (Col-0), etr1-2, and 35S:OsRTH1 transformants in the corresponding mutation background as indicated. Error bars indicate the standard error (SE) for the means of five measurements. RT-PCR, analysis of the mRNA level of corresponding transgenes at the translational level. a (air) and b (ethylene) indicate a statistically significant difference (a-0.01) between the wild type and mutant or transformation lines.

                                                             Fig.1 expression in Arabidopsis

2. GFP-fused OsRTHs are associated with the Golgi(fig.2).

                                                             Fig. 2 GFP-fused OsRTHs location

3. OsRTH1 overexpression prevents ethylene-induced riceleaf senescence(fig.3).

                                                              Fig. 3 OsRTH1 overexpression in rice

Evolution

The RTH sequence and gene structure of evolutionarily representative plant species, including Physcomitrella patens, Selaginella moellendorffii, Arabidopsis, and rice were compared (Banks et al., 2011).

In addition to the putative, C-terminal transmembrane domains, these RTHs have two conserved regions (CR1 and CR2) and two non-conserved regions (NCR1 and NCR2). NCR1 may not have a role in RTE1 function because the NCR1-lacking ND49rte1 isoform is still functional in ethylene signalling (Zhou et al., 2007) (Fig. 4A). The structures of AtRTH, OsRTH1 (Os01g0711600), and OsRTH3 (Os03G0799500) are similar to that of RTE1.They have three exons and two introns. The putative start codon is located at the beginning of exon 2 and the stop codon is located at the end of exon 3. PpRTH1 and OsRTH2 (Os05g0539800) are structurally distinct from RTE1 and have three introns and four exons (Fig. 4B). Because of the lack of genomic sequence information, the gene structures for the moss PpRTH2 and lycophyte SmRTH could not be compared. On pairwise sequence alignment of RTHs and RTE1 (http://www.ebi.ac.uk/Tools/psa/emboss_needle/), RTE1 had the highest sequence identity with and similarity to OsRTH1, and the lowest with AtRTH, OsRTH3, and RTHs of lower plants (Fig. 4C).

                                                            Fig. 4

Labs working on this gene

1. National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai), Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

2. Plant Gene Research Center, National Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences.

References

1. Greco M, Chiappetta A, Bruno L, et al. In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning[J]. Journal of experimental botany, 2012, 63(2): 695-709.

2. Wuriyanghan H, Zhang B, Cao W H, et al. The ethylene receptor ETR2 delays floral transition and affects starch accumulation in rice[J]. The Plant Cell Online, 2009, 21(5): 1473-1494.