Altered physiology in trehalose-producing transgenic tobacco plants: Enhanced tolerance to drought and salinity stresses

Abstract

Transgenic tobacco (Nicotiana tabacum L. var. SR1) plants that over-express the Escherichia coli trehalose-6-phosphate synthase (TPS) gene (otsA) synthesized small amounts of trehalose (<400 pg gl leaf) while non-transformants produced no detectable trehalose. Some transgenic plants expressing a high level of otsA exhibited stunted growth and morphologically altered leaves. We tested F2 homozygous plants devoid of phenotypic changes to determine their physiological responses to dehydration and salinity stresses. All transgenic plants maintained better leaf turgidity under a limited water supply or after treatment with polyethylene glycol (PEG). Furthermore, fresh weight was maintained at higher levels after either treatment. The initial leaf water potential was higher in transgenic plants than non-transformants, but, in both plant types, was decreased to a comparable degree following dehydration. When grown with 250 mM NaCI, transgenic plants exhibited a significant delay in leaf withering and chlorosis, as well as more efficient seed germination. Our results suggest that either trehalose or trehalose-6-phosphate can act as an osmoprotective molecule without maintaining water potential, in contrast to other osmolytes. Furthermore, both appear to protect young embryos under unfavorable water status to ensure subsequent germination.

Development of transgenic cucumber expressing TPSP gene and morphological alterations

“…Thus, trehalose allows plants to tolerate naturally occurring stress during the period of dehydration and rehydration (Drennan et al 1993). Transgenic tobacco plants expressing TPS or otsA gene were shown the enhancing of dehydration tolerance (Romero et al 1997), and trehalose-producing tobacco plants showed enhanced tolerance to drought and salinity stresses (Jun et al 2005). Similar results were also reported in transgenic rice plants increases trehalose accumulation and abiotic stresses tolerance (Jang et al 2003;Garg et al 2002).…”

Combined effects of drought and CO2 enrichment on foliar metabolites of potato (Solanum tuberosum L.) cultivars

“…proline, inositol, raffinose, galactinol, and trehalose, was also reported (Schafleitner et al, 2007;Vasquez-Robinet et al, 2008;Evers et al, 2010;Legay et al, 2011;Kondrak et al, 2012). The overexpression of genes involved in Pro and trehalose biosynthesis also enhanced drought tolerance in several crops (Garg et al 2002;de Ronde et al 2004;Cortina & Culianez-Macia 2005;Jun et al 2005). Sugars including raffinose are also important in controlling ROS production during drought stress (Pelleschi et al 1997).…”

RNAi-mediated abrogation of trehalase expression does not affect trehalase activity in sugarcane

“…Pleiotropic effects resulting in developmental abnormalities due to constitutive expression of these genes have been reported in tobacco, potato and tomato (Cortina and Culianez-Macia 2005; Jun et al 2005; Yeo et al 2000). T6P may be responsible for these effects because engineering strategies that minimize free T6P concentrations report the absence of negative pleiotropic effects.…”