Cloning and characterization of TaSnRK2.3, a novel SnRK2 gene in common wheat

Abstract

Environmental stresses such as drought, salinity, and cold are major adverse factors that significantly affect agricultural productivity. Protein phosphorylation/dephosphorylation is a major signalling event induced by osmotic stress in higher plants. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members play essential roles in the response to hyperosmotic stresses in plants. In this study, the TaSnRK2.3 gene, a novel SnRK2 member was cloned, and three copies located on chromosomes 1A, 1B, and 1D were identified in common wheat. TaSnRK2.3 was strongly expressed in leaves, and responded to polyethylene glycol, NaCl, abscisic acid, and cold stresses. To characterize its function, transgenic Arabidopsis overexpressing TaSnRK2.3–GFP controlled by the cauliflower mosaic virus 35S promoter was generated and subjected to severe abiotic stresses. Overexpression of TaSnRK2.3 resulted in an improved root system and significantly enhanced tolerance to drought, salt, and freezing stresses, simultaneously demonstrated by enhanced expression of abiotic stress-responsive genes and ameliorative physiological indices, including a decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and significantly increased osmotic potential and free proline content under normal and/or stressed conditions. These results demonstrate that TaSnRK2.3 is a multifunctional regulator, with potential for utilization in transgenic breeding for improved abiotic stress tolerance in crop plants.

ABA Regulation of the Cold Stress Response in Plants

“…The PYR/PYL/RCAR family of proteins are ABA receptors that can inhibit the activity of the type-2C protein phosphatase PP2C in the presence of ABA, relieving the repression of the SnRK2 kinases activity, which in turn phosphorylates other downstream regulators (Furihata et al 2006;Ma et al 2009;Park et al 2009). Overexpression of TaSnRK2.3 in Arabidopsis results in enhanced root-system architecture and significantly enhances the tolerance of this species to drought, salt, and freezing stresses (Tian et al 2013), whereas downregulation of PP2CA proteins increases ABA sensitivity and accelerates cold acclimation in transgenic plants (Tahtiharju and Palva 2001). Promoter analysis found that some DRE/CRT motif-containing COR genes are induced by cold and dehydration and impaired in ABA-deficient mutants (Thomashow 1999;Shinozaki and YamaguchiShinozaki 2000).…”

Overexpression of ZmMAPK1 enhances drought and heat stress in transgenic Arabidopsis thaliana

“…Environmental stresses often cause physiological changes in plants, so such indices are used to evaluate abiotic stress tolerance and resistance in crops (Tian et al 2013). ROS is the main product of heat stress, and MAPKs are the key players in ROS signaling (Pitzschke and Hirt 2009;Zhang et al 2010).…”

“…Total chlorophyll content was measured with a chlorophyll meter (SPAD 502 Plus; Konica Minolta Sensing) as described previously (Abe et al 2012;Tian et al 2013). Measurements of chlorophyll content under stress conditions were performed after applying a treatment of 37 °C for 3 days.…”

Characterization of genomic sequence of a drought-resistant gene TaSnRK2.7 in wheat species

“…Recently, the AtSnRK2.6 protein was found to mediate the regulation of sucrose metabolism and plant growth in Arabidopsis (Zheng et al 2010). In our previous study, the overexpression of wheat SnRK2s in Arabidopsis resulted in high total soluble sugars and enhanced tolerance to stresses Zhang et al 2011c;Tian et al 2013) It was speculated that soluble sugar accumulation may lower the osmotic potential in the plant sap, maintaining regular cell turgor and avoiding damage to cell membranes that would enhance osmotic stress. In the present study, TaSnRK2.7 transcripts and total soluble sugars increased significantly under PEG treatments (figure 3), indicating that TaSnRK2.7 and sugar metabolism is playing a role in stress tolerance.…”

“…Individual members of SnRK2 have acquired different regulatory properties under stress signaling (Boudsocq et al 2007;Huai et al 2008;Mao et al 2010;Tian et al 2013;Xu et al 2013). Furthermore, SnRK2 kinases are also involved in the regulation of carbon metabolism and energy status in their respective systems, similar to the function of sucrose nonfermenting 1 (SNF1) in yeast, which is activated in response to low cellular glucose levels by directly modulating the * For correspondence.…”