Isolation and characterization of drought-related trehalose 6-phosphate-synthase gene from cultivated cotton (Gossypium hirsutum L.)

Abstract

Due to the important role of cotton drought-tolerant varieties and the reported involvement in this trait of trehalose-6-phosphate-synthase, the respective gene (TPS) was isolated and characterized from cultivated cotton, Gossypium hirsutum (ZETA 2 cultivar), using a chromosome-walking technique. TPS has three exons comprising the coding region. Southern blot analysis indicated that the Gossypium genomes (A and D) contain a single copy of TPS per genome. In addition, the expression of this gene was studied in different plant tissues. Plants of the Australian cotton variety Siokra L23, known for its drought tolerance, were subjected to drought stress (using PEG 6,000 solution, for 4 h during the dark period of the day and for four consecutive days); leaves, stems and roots were collected after the end of the stress period. Total extracted RNA was examined for the presence of transcripts, in the above-mentioned tissues of stressed and well-watered plants, by reverse transcription-polymerase chain reaction (RT-PCR). The expression levels, determined semi-quantitatively, indicated that the gene was expressed in all plant tissues under both water availability conditions. However, increased expression levels of TPS were observed mainly in stressed leaves and roots compared to those of the well-watered control. This finding is in agreement with the fact that TPS participates in trehalose biosynthesis, known for its participation in stress signal transduction in higher plants.

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

“…Trehalose accumulation in response to water stress in wheat was associated with a decrease in trehalase activity (El-Bashiti et al, 2005;Kosmas et al, 2006). However, trehalose levels were still relatively low and unlikely to make much contribution to osmoregulation unless very localized.…”

Plant Drought Stress: Effects, Mechanisms and Management

“…Capacity to produce trehalose, earlier thought to be absent from higher plants, has now been reported to accumulate in high amounts in some drought-tolerant ferns, the resurrection plant Selaginella lepidophylla (Penna, 2003) and desiccation-tolerant angiosperm Myrothamnus flabellifolia (Drennan et al, 1993). The presence of low amounts of trehalose was demonstrated even in tobacco (Goddijn et al, 1997) and many higher plants (Kosmas et al, 2006). Its metabolism may be channelized to enhance drought tolerance in plants ( Pilon-Smits et al, 1998;Penna, 2003).…”

Expression Analysis of Two Genes Coding for Trehalose-6-Phosphate Synthase (TPS), in Sugarcane (<i>Saccharum</i> spp.) under Water Stress

“…This probable high number of isoforms of TPS in sugarcane may be due to the polyploidy and the hybrid condition associated to the Saccharum spp. As well as in sugarcane, transcripts of TPS genes in several plant tissues like in Arabidopsis [8,12], rice [33] and maize [34] were found. The in silico expression indicates a constitutive expression of TPS genes in several tissues and treatment approaches in the hibrid sugarcane plants.…”

“…Arabidopsis thaliana [8][9][10], rice, potato [11] and cotton [12]. Leyman et al [9] found 11 similar TPS genes presumably functional in the genome of Arabidopsis.…”

“…Besides, there is a strong evidence that the TPS enzyme also acts as a signaling molecule [15]. Trehalose is an efficient osmoprotectant in many organisms, however, according to Kosmas et al [12], the enhanced stress resistance in transgenic plants that super-expressed TPS genes, is not assigned to the accumulation of this carbohydrate, since, its concentrations in the plant are unlikely to be sufficient for its osmoprotectant effects. Avonce et al [19] verified that the super-expression of the AtTPS1 gene (class I) in Arabidopsis conferred drought tolerance without causing morphologic changes in the plant.…”