Overexpression of the trehalose-6-phosphate synthase gene OsTPS1 enhances abiotic stress tolerance in rice

Abstract

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). The genome of rice (Oryza sativa) contains 11 OsTPS genes, and only OsTPS1 shows TPS activity. To demonstrate the physiological function of OsTPS1, we introduced it into rice and found that OsTPS1 overexpression improved the tolerance of rice seedling to cold, high salinity and drought treatments without other significant phenotypic changes. In transgenic lines overexpressing OsTPS1, trehalose and proline concentrations were higher than in the wild type and some stress-related genes were up-regulated, including WSI18, RAB16C, HSP70, and ELIP. These results demonstrate that 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. Furthermore, we found that overexpression of some Class II TPSs also enhanced plant tolerance of abiotic stress. This work will help to clarify the role of trehalose metabolism in abiotic stress response in higher plants.

A Tale of Two Sugars: Trehalose 6-Phosphate and Sucrose

“…More targeted interventions have generally been more successful strategies; these include (1) limiting expression to specific subcellular compartments or tissues, (2) use of endogenous plant genes, and (3) placing the introduced genes under the control of stressinducible promoters (Garg, et al, 2002;Lee et al, 2003;Avonce et al, 2004;Miranda, et al, 2007;Stiller et al, 2008;Li et al, 2011;Kondrák et al, 2012). However, in most cases the enhanced stress tolerance did not appear to be linked to increased trehalose accumulation.…”

Tackling Drought Stress: RECEPTOR-LIKE KINASES Present New Approaches

“…An increase in stress tolerance is often aimed for by rather general approaches, namely, ectopic overexpression or knockdown of a particular key component of stress signaling pathways (Nelson et al, 2007;Xiao et al, 2007;Castiglioni et al, 2008;Jung et al, 2008;Li et al, 2011;Song et al, 2011;Yan et al, 2011). Ectopic expression of components involved in abiotic stress responses has led to improved stress tolerance, but also reduced plant growth (Flowers, 2004;Bartels and Sunkar, 2005;Umezawa et al, 2006).…”

Overexpression of the Trehalase Gene AtTRE1 Leads to Increased Drought Stress Tolerance in Arabidopsis and Is Involved in Abscisic Acid-Induced Stomatal Closure

“…The undesired abnormalities in these plants were ascribed to altered levels of T6P, perturbing the developmental processes influenced by this important signal metabolite (Eastmond et al, 2003;Schluepmann et al, 2003Schluepmann et al, , 2004. Plants with improved stress tolerance but no obvious morphological defects were obtained by introducing bifunctional TPS-TPP constructs (Garg et al, 2002;Karim et al, 2007;Miranda et al, 2007), by placing the introduced TPS genes under the control of droughtinducible or tissue-specific promoters (Garg et al, 2002;Karim et al, 2007), or by overexpressing the plant endogenous TPS1 in Arabidopsis (Avonce et al, 2004) and rice (Oryza sativa; Li et al, 2011). It seems unlikely that the increased drought tolerance in these transgenic lines could be ascribed to trehalose acting as an osmoprotectant, since the trehalose levels never exceeded 1 mg g 21 fresh weight (Garg et al, 2002;Avonce et al, 2004;Cortina and Culianez-Macia, 2005).…”