Genetic engineering of drought-resistant tobacco plants by introducing the trehalose phosphorylase (TP) gene from Pleurotus sajor-caju

Abstract

This study generated transgenic tobacco plants expressing trehalose phosphorylase of Pleurotus sajor-caju (PsTP) constitutively under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Sixteen transgenic lines were selected by genomic Southern blot analysis for further study. Unlike yeast TPS1-transformed or Escherichia coli TPS1-transformed tobacco or potato, all of the PsTP transgenic tobacco lines showed normal growth phenotypes both in the culture tubes and soil mixture. The study measured the trehalose contents of PsTP-transformed tobacco plants as well as the wild type and empty vector-transformed control plants. Results showed that the PsTP transformant contained 6.3 lmol g )1 of plant tissues, while the wild type and the control plants had only minimal levels of trehalose. Because this study detected a significant amount of trehalose in PsTP transgenic tobacco plants, it decided to carry out a bioanalysis of the PsTP transgenic tobacco plants by drought treatment by not watering the plants for over 10 days. A significant difference in drought resistance was observed from the second nonwatering day between the transgenic and the control tobacco plants. The transgenic tobacco plants had normal growth and did not wither, while the wild type and the only empty vector-transformed control plants withered severely. Among all the transgenic lines, line 10-4 showed the strongest resistance to drought stress. It did not wither even after 10 days without watering. In addition, when the drought resistance of PsTP transgenic tobacco plants was tested using detached leaves, most transgenic plants, except one line, showed better capacity to retain water than the empty vector-transformed transgenic plant.

Source/sink interactions underpin crop yield: the case for trehalose 6-phosphate/SnRK1 in improvement of wheat

“…Similarly, transformation of tobacco chloroplasts with yeast TPS1 gene decreased growth rate of To plants but not later generations compared to the wild-type and was considered to confer drought tolerance (Lee et al, 2003). Plants transformed to increase the content of T6P and TRE were more “drought resistant” than the wild-type (Han et al, 2005) but this was stated not to affect growth. Similarly, Karim et al (2007) used constructs which did not to affect growth but did slow water loss.…”

Trehalose and Abiotic Stress in Biological Systems

“…Since trehalose has been found to participate in increasing tolerance to abiotic stresses in other organisms, many attempts have been made to engineer plants with microbial trehalose biosynthetic genes from OtsA-OtsB pathway in order to create stress tolerant plants: tobacco (Holmstrom et al, 1996;Goddijn et al, 1997;Romero et al, 1997;Pilon-Smits et al, 1998;Lee et al, 2003;Han et al, 2005;Karim et al, 2007), rice (Garg et al, 2002;Jang et al, 2003), tomato (Cortina & Culianez-Macia, 2005), potato (Goddijn et al, 1997) and Arabidopsis (Karim et al, 2007;Miranda et al, 2007). The first trials were partially successful, trehalose accumulated, albeit at a low level, the plants were stress tolerant, however they displayed abnormal phenotype characteristics (Goddijn et al, 1997;Romero et al, 1997;Pilon-Smits et al, 1998;Cortina & Culianez-Macia, 2005).…”

“…The first trials were partially successful, trehalose accumulated, albeit at a low level, the plants were stress tolerant, however they displayed abnormal phenotype characteristics (Goddijn et al, 1997;Romero et al, 1997;Pilon-Smits et al, 1998;Cortina & Culianez-Macia, 2005). Nonetheless, subsequent studies solved the phenotype problem by using fused bacterial trehalose biosynthesis genes, directing the gene constructs to chloroplasts (Garg et al, 2002;Jang et al, 2003;Karim et al, 2007;Miranda et al, 2007), or engineering the plants with alternate trehalose biosynthesis genes, as trehalose phosphorylase (TreP), which circumvented the production of trehalose-6-phoaphate (Han et al, 2005). The symbiotic relationship between rhizobia and legumes has a considerable impact not only on the legumes yields but also on the significant amount of the fixed nitrogen that remains in the soil for future crops use.…”

Targeting carbon for crop yield and drought resilience

“…Generally, soluble carbohydrate accumulation will occur in tandem with proline and anthocyanin accumulation, aiding the protection against ROS in the first instance . The disaccharide trehalose has been implicated in drought tolerance processes in several studies . Under drought stress conditions, the accumulation of trehalose potentially aids in the stabilisation of phospholipid membranes, proteins and nucleic acids, although, in most plants, insufficient trehalose accumulates to enable this function.…”