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. 2014 Jul;65(12):3277-87.
doi: 10.1093/jxb/eru178. Epub 2014 Apr 30.

RAN1 is involved in plant cold resistance and development in rice (Oryza sativa)

Peipei Xu  1 , Weiming Cai  2
Affiliations

RAN1 is involved in plant cold resistance and development in rice (Oryza sativa)

Peipei Xu et al. J Exp Bot. 2014 Jul.

Abstract

Of the diverse abiotic stresses, low temperature is one of the major limiting factors that lead to a series of morphological, physiological, biochemical, and molecular changes in plants. Ran, an evolutionarily conserved small G-protein family, has been shown to be essential for the nuclear translocation of proteins. It also mediates the regulation of cell cycle progression in mammalian cells. However, little is known about Ran function in rice (Oryza sativa). We report here that Ran gene OsRAN1 is essential for the molecular improvement of rice for cold tolerance. Ran also affects plant morphogenesis in transgenic Arabidopsis thaliana. OsRAN1 is ubiquitously expressed in rice tissues with the highest expression in the spike. The levels of mRNA encoding OsRAN1 were greatly increased by cold and indoleacetic acid treatment rather than by addition of salt and polyethylene glycol. Further, OsRAN1 overexpression in Arabidopsis increased tiller number, and altered root development. OsRAN1 overexpression in rice improves cold tolerance. The levels of cellular free Pro and sugar levels were highly increased in transgenic plants under cold stress. Under cold stress, OsRAN1 maintained cell division and cell cycle progression, and also promoted the formation of an intact nuclear envelope. The results suggest that OsRAN1 protein plays an important role in the regulation of cellular mitosis and the auxin signalling pathway.

Keywords: Cold tolerance; OsRAN1; cell division; intact nuclear envelope.; reduced apical dominance.

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Figures

Fig. 1.
Fig. 1.
Phylogenetic analysis of plant Ran GTPase, tissue specific expression of OsRAN1, and its subcellular localization. (A) Phylogenetic tree of plant Ran GTPases. The tree was constructed with the MEGA5.1 software with amino acid sequences of rice OsRAN1, OsRAN1, and other Ran GTPases isolated from wheat (TaRAN1), Arabidopsis (AtRAN1, AtRAN2, AtRAN3), human (RAN/TC4), and mouse (MusRAN). (B) Quantitative real-time PCR quantification of OsRAN1 expression across different rice plant organs. Data are means±SD (n=3–5). Panicles, leaves, stems, and roots were harvested from individual 8–9-week-old wild-type plants. Stem expression was set to 1. (C) Subcellular localization of OsRAN1 in transgenic Arabidopsis root cells and tobacco epidermal cells; (d).Transient expression of OsRAN1:GFP in tobacco epidermal cells; DIC, differential interference contrast, referring to brightfield images of the cells.
Fig. 2.
Fig. 2.
Semi-quantitative RT-PCR analysis of OsRAN1 expression in stress response. (A, B). Time course of OsRAN1 expression during cold treatment (4 °C). (C, D) Time course of OsRAN1 expression during treatment with 150mm NaCl. (E, F) Time course of OsRAN1 expression during treatment with 10% PEG 6000, a mimic for drought stress. (G, H). Time course of OsRAN1 expression during treatment with 1 μM IAA. The rice seedlings were germinated and grew for 10 d before they were treated with cold, salt, drought, and IAA stresses. OsUbiquitin was used as an internal control.
Fig. 3.
Fig. 3.
T2 generation phenotypes of different lines in overexpressed OsRAN1 transgenic Arabidopsis. (A) Rosette leaves of wild-type Arabidopsis grown for 3 weeks. (B) Increased rosette leaves of transgenic Arabidopsis grown for 3 weeks. (C) Apical inflorescence of wild-type Arabidopsis. (D) Apical inflorescence including partial abortion of transgenic Arabidopsis. (E) Normal floral apical dominance of wild-type Arabidopsis. (F) Increased tillery number in 35S-sense OsRAN1 transgenic mature Arabidopsis. (G) Normal phenotype of wild-type Arabidopsis. (H) Two branches with rosette leaves in a transgenic plant. (I) Wild-type and transgenic 6-d-old seedlings with elongated hypocotyl in the light. (J) Wild-type and transgenic 6-d-old seeding’s in the dark. (K) Time curve of development of rosette leaves in wide-type and transgenic Arabidopsis plants. (L) Normal 10-d-old seeding. (M, N) Transgenic Arabidopsis with much fewer lateral roots and shorter main roots. (O) Statistical analysis of wild-type and transgenic lines main root length. (P) Statistical analysis of lateral root number in wild-type and transgenic lines. Asterisk indicates significant difference P<0.01.
Fig. 4.
Fig. 4.
Effect of auxin on root development in transgenic Arabidopsis plants. (A) Effect of IAA (10−9 or 10−7 M) on growth of primary roots in transgenic plants of Arabidopsis. The transgenic plants treated with IAA affected primary root growth compared with wild-type plants. (B) Effect of IAA (10−9 or 10−7 M) on lateral root in transgenic Arabidopsis plant. Results are presented as average values±SE from three experiments. More than ten roots were used in each experiment. Asterisk indicates significant difference P<0.01.
Fig. 6.
Fig. 6.
Cold tolerance analysis of transgenic rice overexpressing OsRAN1. (A) Two-week-old OE transgenic and WT plants (top photographs) were cold stressed at 4 °C for 84h and then transferred back to the normal condition for recovery. (B) Photographs of representative seedlings of WT and three transgenic lines were taken after 14 d of recovery. (C) Real-time RT-PCR analysis of the expression of OsRAN1 in transgenic rice relative to that of actin. Data represent means and SE of three replicates. OE3, OE5, OE7, OE9, OE11, OE13, OE15, OE18, OE23, OE27, OE34, OE38, OE47, OE53, OE55, OE57 represent transgenic lines overexpressing (OE) OsRAN1. (D) Survival analysis of WT and OsRAN1 transgenic plants 14 d after cold treatment. Error bars indicate standard deviation and results are from three independent replications of the same experiment. The phenotype was confirmed by further experiments that were repeated more than three times. Asterisk indicates significant difference P<0.01. (This figure is available in colour at JXB online.)
Fig. 5.
Fig. 5.
Comparison of cell numbers between transgenic plants and wild-type rice. Primary root meristem zone of primary roots of wild-type (A) and transgenic (B) rice stained with propidium iodide. The number of transgenic rice cells in the meristem was increased over those in the wild type. Bar=50 μm. (C) Cell number in primary roots meristem elongation. Results are presented as mean±SE from three experiments (n=5–10). Bar=50 μm. Asterisk indicates significant difference P<0.01. (This figure is available in colour at JXB online.)
Fig. 8.
Fig. 8.
Cell cycle progression and mean root tip mitotic index of wild-type and transgenic rice overexpressing OsRAN1 during cold stress. (A) The wild-type at 28 °C. (B) The wild-type at 4 °C. (C) Overexpressing line 47 (OE47) of OsRAN1 transgenic rice at 28 °C. (D) Overexpressing line 47 at 4 °C. Seedlings 7 d after germination were treated with low temperature (4 °C) or room temperature (control, 28 °C) for 12h. Cell nuclei (10 000) taken from the root apical meristem were stained with DAPI and analysed by flow cytometry. 2C and 4C represent the DAPI signals that correspond to nuclei with different DNA contents. (E) Cell mitotic index in root apical meristem (RAM) in rice. The error bars show SE and are from three independent replications of the same experiment. Six root tips were analysed in every replicate. Asterisk indicates significant difference P<0.01. (This figure is available in colour at JXB online.)
Fig. 7.
Fig. 7.
Contents of soluble sugars and free Pro in transgenic rice plants overexpressing OsRAN1 compared with the wild-type plants under normal and cold stress. Free Pro (A) and soluble sugar (B) contents in the OsRAN1-overexpressing plants under cold stress (4 °C) for 3 d. Values are means±SD (n=4). FW, fresh weight. (C) Expression levels of putative Pro synthesis genes (AK102633 and AK101230) and Pro transporter genes (AK067118 and AK0666298) in cold-stressed (4 °C for 1 d) OsRAN1 transgenic plants by real-time PCR. (D) Expression levels of putative sugar synthesis relative genes (Os01g0205700 and OsSPS1) and sugar putative transporter genes (Os08g0178200 and Os12g0641400) and two putative sugar transporter genes (Os08g0178200 and Os12g0641400) in cold-stressed (4 °C for 1 d) OsRAN1 transgenic plants by real-time PCR. The bars represent three repeats. Asterisk indicates significant difference P<0.01.
Fig. 9.
Fig. 9.
Morphologies changes of the nuclear envelope in the wild type (WT) and transgenic line under cold stress. Nuclear envelope of the WT (A) and OsRAN1-overexpressing line 47 (B) under normal conditions (28 °C); nuclear envelope of the WT (E, F) and OsRAN1-overexpressing line (C, D) after 3h treatment at 4 °C. Six root tips were observed in every condition. The root tips were transversely cut in the meristematic zones. Arrows indicate the nuclear envelope. Bars=500nm.
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References

    1. Abraham E, Rigo G, Szekely G, Nagy R, Koncz C, Szabados L. 2003. Light-dependent induction of proline biosynthesis by abscisic acid and salt stress is inhibited by brassinosteroid in Arabidopsis . Plant Molecular Biology 51, 363–372 - PubMed
    1. Ach RA, Gruissem W. 1994. A small nuclear gtp-binding protein from tomato suppresses a Schizosaccharomyces pombe cell-cycle mutant. Proceedings of the National Academy of Sciences, USA 91, 5863–5867 - PMC - PubMed
    1. Andaya VC, Tai TH. 2006. Fine mapping of the qCTS12 locus, a major QTL for seedling cold tolerance in rice. Theoretical and Applied Genetics 113, 467–475 - PubMed
    1. Berleth T, Mattsson J, Hardtke CS. 2000. Vascular continuity and auxin signals. Trends in Plant Science 5, 387–393 - PubMed
    1. Bischoff FR, Ponstingl H. 1991. Catalysis of guanine-nucleotide exchange on Ran by the mitotic regulator RCC1. Nature 354, 80–82 - PubMed

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