Introgression of a novel cold and drought regulatory‐protein encoding CORA‐like gene, SbCDR, induced osmotic tolerance in transgenic tobacco

Abstract

A potent cold and drought regulatory-protein encoding gene, SbCDR was cloned from an extreme halophyte Salicornia brachiata. In vitro localisation study, performed with SbCDR::RFP gene-construct revealed that SbCDR is a membrane protein. Overexpression of the SbCDR gene in tobacco plants confirmed tolerance against major environmental constraints such as salinity, drought and cold, as evidenced by improved chlorophyll contents, plant morphology, plant biomass, root length, shoot length and seed germination efficiency. Transgenic lines also exhibited high accumulation of proline, total sugar, reducing sugar, free amino acid and polyphenol, besides the low level of malondialdehyde (MDA) contents. SbCDR transgenic lines showed better relative water contents, membrane stability index and osmotic water potential. Furthermore, higher expression of ROS scavenging genes was observed in transgenic lines under stress. Moreover, microarray analysis revealed that several host genes were upregulated and downregulated under drought and salt stress conditions in SbCDR transgenic line compared with control (WT) plants. The results demonstrated that the overexpression of the halophytic SbCDR gene has intense effects on the abiotic stress tolerance of transgenic tobacco plants. However, the exact mode of action of SbCDR in multiple abiotic stress tolerance of plants is yet to be unveiled. It is believed that the precise role of SbCDR gene will provide additional information to comprehend the abiotic stress tolerance mechanism. Furthermore, it will appear as a promising candidate gene for improving stress tolerance in different crop plants for sustainable agriculture and crop productivity.

Introgression of SbERD4 Gene Encodes an Early-Responsive Dehydration-Stress Protein That Confers Tolerance against Different Types of Abiotic Stresses in Transgenic Tobacco

“…Seeds of SbERD4 overexpressing transgenic lines (L2, L13, L14, L15, and L18), vector control (VC), and wild-type (WT) plants were kept on MS media for germination under control (no additional supplementation) and stress conditions (by supplementing 200 mM NaCl for salinity or 300 mM mannitol for osmotic/drought) for 21 days, and the seed-germination percentage was calculated [ 30 , 31 ]. Different growth parameters, including root (RL) and shoot (SL) length, fresh (Fw) and dry (Dw) weight were calculated and compared with control (WT and VC) plants grown under salinity (200 mM NaCl) and osmotic/drought (300 mM mannitol) stress conditions.…”

“…The fresh weight (Fw) of leaf samples of transgenic and control (WT and VC) plants (treated and untreated) was recorded, and samples were incubated in deionized water for 24 h. After incubation, turgid weight (Tw) was measured, which was followed by dry weight (Dw) measurement at 40 °C. The percentage of relative water content (RWC) was calculated [ 30 ] by the following equation: …”

Overexpression of differentially expressed AhCytb6 gene during plant-microbe interaction improves tolerance to N2 deficit and salt stress in transgenic tobacco

“…A transgenic plant that performed better compared to other lines was selected for the differential transcript expression profiling 62 , 70 . Forty-two days old plant grown under N 2 starvation (21 days) stress condition and a plant (42-days old) subjected to NaCl (150 mM for 24 h) stress were used for microarray analysis along with corresponding control plants.…”

Plants Metabolome Study: Emerging Tools and Techniques

“…Increased levels of the glutathione metabolite, γ-aminobutyric acid (GABA), as well as accumulation of β-cyanoalanine, a byproduct of ethylene biosynthesis, were observed in the DREB1A transgenic lines [45] (Table 2). Nicotiana tabacum NMR Chlorogenic acid, 4-O-caffeoylquinic acid, malic acid, threonine, alanine, glycine, fructose, β-glucose, α-glucose, sucrose, fumaric acid and salicylic acid [49] N. tabacum GC-MS 4-Aminobutanoic acid, asparagine, glutamine, glycine, leucine, phenylalanine, proline, serine, threonine, tryptophan, chlorogenic acid, quininic acid, threonic acid, citric acid, malic acid and ethanolamine [50] Oryza sativa GC-MS Glycerol-3-phosphate, citric acid, linoleic acid, oleic acid, hexadecanoic acid, 2,3-dihydroxypropyl ester, sucrose, 9-octadecenoic acid, 2,3-dihydroxypropyl ester, sucrose, mannitol and glutamic acid [44] O. sativa LC-MS Tryptophan, phytosphingosine, palmitic acid, 5-hydroxy-2-octadenoic acid 9,10,13-trihydroxyoctadec-11-enoic acid and ethanolamine [51] Populus…”

“…Metabolomic profiling also demonstrated that introduction of the cold and drought regulatory-protein encoding CORA-like gene (SbCDR) from S. brachiata into tobacco could enhance salt and drought tolerance by increasing the stress related metabolites such as proline, threonine, valine, glyceric acid, fructose, 4-aminobutanoic acid, asparagine [50]. Overexpression of a native UGPase2 gene induced several metabolites related to amino acid, phenolic glycosides such as asparagine, γ-amino-butyric acid, aspartic acid, glutamine, 5-oxo-proline, 2-methoxyhydroquinone-1-O-glucoside, 2-methoxyhydroquinone-4-O-glucoside, salicylic acid-2-O-glucoside, 2,5-dihydroxybenzoic acid-5-O-glucoside, salicin in transgenic Populus lines [52].…”