Os05g0518600

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Oryza sativa trehalose-6-phosphate synthase (OsTPS1) gene is a member of OsTPS genes in rice, it belongs to Class I[1].

Annotated Information

Function

  • Trehalose-6-phosphate (T6P), an intermediate in the trehalose biosynthesis pathway, is emerging as an important regulator of plant metabolism and development. T6P levels are potentially modulated by a group of trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) homologues[1].
  • OsTPS1 overexpression improved the tolerance of rice seedling to cold, high salinity and drought treatments without other significant phenotypic changes. OsTPS1 may enhance the abiotic stress tolerance of plants by increasing the amount of trehalose and proline, and regulating the expression of stress-related genes, including WSI18, RAB16C, HSP70, and ELIP. Overexpression of some Class II TPSs also enhanced plant tolerance of abiotic stress[2].
  • Rather than playing a role in specific plant organs or stress response, OsTPS1 may instead be involved in general regulation, and have a broader role in plant development and stress signaling,which was similar to AtTPS1 which is expressed ubiquitously in Arabidopsis[2][3].
  • Gel filtration assay showed that there may exist two forms of OsTPS1 (OsTPS1a and OsTPS1b) with different elution profiles in rice. OsTPS1b was particularly cofractionated with OsTPS5 and OsTPS8 in the 360 kDa complex, while OsTPS1a was predominantly incorporated into the complexes larger than 360 kDa. OsTPS family members may form trehalose-6-phosphate synthase complexes and therefore potentially modify T6P levels to regulate plant development.[1].

GO assignment(s): GO:0005992

Mutation

  • yeast tps1[2] and tps2 mutantsmutant[1]:

only OsTPS1 encodes an active TPS enzyme and no OsTPS protein possesses TPP activity.

  • An N-terminal truncation(1–130) deleted construct, and demonstrated that the truncated OsTPS1 (131–985) had higher TPS activity than the full length OsTPS1 in a yeast tps1 mutant using yeast complementation assay[2].
  • five T2 transgenic[2]:
    • 9-5, 25-3, 39-5, 46-3, and 51-6
  • WT (ZH11)
  • three independent homozygous T3 transgenic lines[2].
    • two high expression lines (25-3-9, 51-6-3)
    • a low expression line (39-5-1)
    • They were exposed to low temperature(4°C for 5 days), drought (air dried for 4–5 h), high salinity (150 mM NaCl for 3 days) or osmotic stress (20% PEG for 3 days), and then transferred to normal conditions to restore growth.
    • In lines 25-3-9 and 51-6-3, the levels of OsTPS1 expression were moderately higher than that in the WT, whereas in the other three lines expression was equal to WT level.
    • In the drought tolerance test, the OsTPS1 transgenic lines had higher survival rates than WT plants. The survival rate of OsTPS1 transgenic plants (lines 39-5-1, 25-3-9, and 51-6-3) were 6.25, 39.58, and 35.42%, respectively, whereas WT survival was only 2.08%. Using PEG to simulate drought produced similar results.
    • In the cold tolerance test, OsTPS1 transgenic plants (lines 39-5-1, 25-3-9, and 51-6-3) had survival rates of 12.5, 79.17, and 89.58%, respectively, whereas the WT plants had a survival rate of 4.17%. In the salt stress test, the survival rates of lines 25-3-9 and 51-6-3 were twofold higher than the WT. However, the low expression line (39-5-1) did not show improved salt tolerance.
  • Seven T1 plants of Line 1C-071-05:

Lanes3 and Lanes8 were T-DNA homozygotes, while Lanes1, Lanes2, and Lanes7 were heterozygotes[4].

  • KO Plants[4]:
    • Lanes3
    • Lanes8
    • At certain time point, our knockout plants are more sensitive to cold or drought stress than are the WT.

Expression

  • There was no significant difierence in OsTPS1 expression levels in any of the tissues samples, which suggesting that OsTPS1 is expressed constitutively throughout the plant. The transgenic lines overexpressing OsTPS1 showed significantly increased tolerance to salinity, drought and cold, and the survival rates were associated with elevated OsTPS1 expression levels[2].
  • Proline accumulated in transgenic rice with or without stress treatment. WSI18, RAB16C, HSP70, and ELIP were significantly induced in OsTPS1 overexpressing transgenic lines. Moreover, OsTPP1 and OsTPP2 which transform T-6-P to trehalose, and TRE1 which is involved in the catabolism of trehalose were also up-regulated. Overall, OsTPS1 is expressed throughout the rice plant and under a variety of abiotic stresses[2].
  • Overexpressing Class II OsTPS genes also improves rice tolerance to abiotic stress: OsTPS2, OsTPS4, OsTPS5, OsTPS8, and OsTPS9 improved the tolerance of rice to cold and salinity stress, and some of them improved the drought tolerance of transgenic rice seedlings (data not shown). Class II OsTPS proteins might regulate OsTPS1 activity in protein complexes depending on their phosphorylation status[2].
  • Reverse transcriptase PCR analysis of OsTPS1 showed that OsTPS1 is inducible by drought, salt, cold, and ABA. Furthermore, transgenic rice of UBI::CBF1 had high expression OsTPS1 mRNA, suggesting that OsTPS1 is regulated by the CBF/DREB transcription factor. Therefore, we propose that OsTPS1 plays an important role during the abiotic stress response[4].
  • OsTPS1 expression was rarely detected in the mature leaves, and was only found at basal levels in the flag leaf sheath,which suggesting that the expression of OsTPS1 is organ-specific. Expression of OsTPS1 is up-regulated in transgenic rice expressing CBF1[4].

Evolution

Figure 1. Dendrogram of the 11 OsTPS proteins.(from reference [1]).
  • The TPS proteins have been classified into two distinct groups based on their homology with the yeast TPS1. However, only TPS1 (belongs to Class I) has demonstrated TPS activity[1][5]. The others belong Class II(Figure 1). The role of Class II TPS proteins which do not have TPS activity is still ambiguous[1][2].
  • OsTPS1 is similar to AtTPS1 and SlTPS1[2].
  • The homologies of OsTPSl to DmTPSl (D, melanogaster), OtsA (E. coli) , SITPSl (S, lepidophylla), ScTPSl (S, cerevisiae), AtTPSl and AtTPS9 (A. thaliaNa) are 20%, 22%, 29%, 32%, 30%, and 52%, respectively. Two distinct regions the TPS and TPP portions that are found in most eukaryotes, are also conserved in OsTPS1[4].
  • Based on the putative CRT/DRE sequence present in the OsTPS1 promoter region, as well as the high expression of OsTPS1 in Ubi::CBF1 rice, we can postulate that OsTPS1 might be a target of the rice orthologue of CBF1[4].

Knowledge Extension

  • Trehalose plays an important role in metabolic regulation and abiotic stress tolerance in a variety of organisms. In plants, its biosynthesis is catalyzed by two key enzymes: trehalose-6-phosphate synthase (TPS) and trehalose- 6-phosphate phosphatase (TPP). TPS and TPP proteins constitute a large protein family in higher plants. There are 11 TPS genes in the Arabidopsis and rice genomes[1][2][6] and at least ten TPP genes in Arabidopsis and nine TPP genes in rice[7][8].
  • However, only a few have been shown to possess activity. In rice, OsTPS1, OsTPP1, and OsTPP2[8][9] proteins have established TPS and TPP activity, respectively. However, the functions of the other TPS and TPP proteins in higher plants remain elusive. Members of this large gene family may have diverse roles in the regulation of metabolism.

Labs working on this gene

  • Key Laboratory of Gene Engineering Drug and Biotechnology, Key Laboratory of Cell Proliferation and Regulation of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, People’s Republic of China
  • Department of Life Science, Sogang University, Seoul 121-742, Korea
  • National Research Laboratory of Plant Functional Cenomics, Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, Korea
  • Peking-Yale Joint Center for Plant Molecular Genetics and Agrobiotechnology, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, People’s Republic of China
  • State Key Laboratory of Genetic Engineering, Fudan University, Shanghai 200433, People’s Republic of China
  • Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
  • National Center for Molecular Crop Design, Weiming Kaituo Agriculture Biotech Co., Ltd, Beijing 100085, People’s Republic of China

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Zang B, Li H, Li W, et al. Analysis of trehalose-6-phosphate synthase (TPS) gene family suggests the formation of TPS complexes in rice[J]. Plant molecular biology, 2011, 76(6): 507-522.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Li H W, Zang B S, Deng X W, et al. Overexpression of the trehalose-6-phosphate synthase gene OsTPS1 enhances abiotic stress tolerance in rice[J]. Planta, 2011, 234(5): 1007-1018.
  3. van Dijken A J H, Schluepmann H, Smeekens S C M. Arabidopsis trehalose-6-phosphate synthase 1 is essential for normal vegetative growth and transition to flowering[J]. Plant physiology, 2004, 135(2): 969-977.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 Kim S J, Jeong D H, An G, et al. Characterization of a drought-responsive gene, OsTPS1, identified by the T-DNA gene-trap system in rice[J]. Journal of Plant Biology, 2005, 48(4): 371-379.
  5. Vandesteene L, Ramon M, Le Roy K, et al. A single active trehalose-6-P synthase (TPS) and a family of putative regulatory TPS-like proteins in Arabidopsis[J]. Molecular plant, 2010: ssp114.
  6. Leyman B, Van Dijck P, Thevelein J M. An unexpected plethora of trehalose biosynthesis genes in< i> Arabidopsis thaliana</i>[J]. Trends in plant science, 2001, 6(11): 510-513.
  7. Ramon M, Rolland F. Plant development: introducing trehalose metabolism[J]. Trends in plant science, 2007, 12(5): 185-188.
  8. 8.0 8.1 Pramanik M H R, Imai R. Functional identification of a trehalose 6-phosphate phosphatase gene that is involved in transient induction of trehalose biosynthesis during chilling stress in rice[J]. Plant molecular biology, 2005, 58(6): 751-762.
  9. Shima S, Matsui H, Tahara S, et al. Biochemical characterization of rice trehalose‐6‐phosphate phosphatases supports distinctive functions of these plant enzymes[J]. FEBS Journal, 2007, 274(5): 1192-1201.

Structured Information