Overexpression of plasma membrane Na+/H+ antiporter OsSOS1 gene improves salt tolerance in transgenic rice plants

2020 ◽  
Vol 57 (4) ◽  
pp. 277-287
Author(s):  
Sushma M Awaji ◽  
Prashantkumar S Hanjagi ◽  
Pushpa BN ◽  
Sashidhar VR

Crop productivity is greatly affected by soil salinity; therefore, improvement in salinity tolerance of crops is a major goal in salt-tolerant breeding. The Salt Overly Sensitive (SOS) signal-transduction pathway plays a key role in ion homeostasis and salt tolerance in plants. In plants pumping of Na+ from the root cells is mediated by the plasma membrane Na+/H+ antiporter (SOS1) which plays important role in preventing the accumulation of toxic levels of Na+ in cytosol. In the present study, OsSOS1 (NHX7), gene was overexpressed in rice (var-Vikas) by Agrobacterium mediated In Planta transformation technique. To screen putative T1 plants for salt tolerance, stringent salt screening test was followed and root and shoot growth of transformants were used as selection criterion. Some of the putative transgenics showed significantly higher root growth compared to wild type. To confirm the presence of transgene in putative T1 transgenic plants, PCR based approach was followed using genomic DNA. The result showed that 16 % of the selected seedlings from the stringent salt screening test were PCR positives. Five selected lines were positive for RT-PCR analysis. Physiological studies such as chlorophyll content, membrane permeability, cell viability and sodium /potassium content analysis were also conducted to assess their levels of tolerance. Some of the T1 transformants showed lower percent reduction in chlorophyll content and less membrane leakage, higher cell viability and maintained higher K/Na ratio after NaCl treatment compared to wild type. These results clearly demonstrate that transgenic rice plants overexpressing OsSOS1 have better salt-tolerance. This could be attributed to extrusion of excess Na+ from cytosol into the apoplast and thereby reducing the toxic effects of Na+in the cell.

Author(s):  
Yuji Suzuki ◽  
Keiki Ishiyama ◽  
Misaki Sugawara ◽  
Yuka Suzuki ◽  
Eri Kondo ◽  
...  

Abstract Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) limits the regeneration of ribulose 1,5-bisphosphate (RuBP) in the Calvin–Benson cycle. However, it does not always limit the rate of CO2 assimilation. In the present study, the effects of overproduction of GAPDH on the rate of CO2 assimilation under elevated [CO2] conditions, where the capacity for RuBP regeneration limits photosynthesis, were examined in transgenic rice (Oryza sativa). GAPDH activity was increased to 3.2- and 4.5-fold of the wild-type levels by co-overexpression of the GAPDH genes, GAPA and GAPB, respectively. In the transgenic rice plants, the rate of CO2 assimilation under elevated [CO2] conditions increased by approximately 10%, whereas that under normal and low [CO2] conditions was not affected. These results indicate that overproduction of GAPDH is effective in improving photosynthesis under elevated [CO2] conditions, although its magnitude is relatively small. By contrast, biomass production of the transgenic rice plants was not greater than that of wild-type plants under elevated [CO2] conditions, although starch content tended to increase marginally.


2007 ◽  
Vol 34 (9) ◽  
pp. 822 ◽  
Author(s):  
Lingling Feng ◽  
Yujun Han ◽  
Gai Liu ◽  
Baoguang An ◽  
Jing Yang ◽  
...  

Activity of the Calvin cycle enzyme sedoheptulose-1,7-bisphosphatase (SBPase; EC3.1.3.37) was increased in the transgenic rice cultivar zhonghua11 (Oryza sativa L. ssp. japonica) by overexpressing OsSbp cDNA from the rice cultivar 9311 (Oryza sativa ssp. indica). This genetic engineering enabled the transgenic plants to accumulate SBPase in chloroplasts and resulted in enhanced tolerance of transgenic rice plants to salt stress at the young seedlings stage. Moreover, CO2 assimilation in transgenic rice plants was significantly more tolerant to salt stress than in wild-type plants. The analysis of chlorophyll fluorescence and the activity of SBPase indicated that the enhancement of photosynthesis in salt stress was not related to the function of PSII but to the activity of SBPase. Western-blot analysis showed that salt stress led to the association of SBPase with the thylakoid membranes from the stroma fractions. However, this association was much more prominent in wild-type plants than in transgenic plants. Results suggested that under salt stress, SBPase maintained the activation of ribulose-1,5-bisphosphate carboxylase-oxygenase by providing more regeneration of the acceptor molecule ribulose-1,5-bisphosphate in the soluble stroma and by preventing the sequestration of Rubisco activase to the thylakoid membrane from the soluble stroma, and, thus, enhanced the tolerance of photosynthesis to salt stress. Results suggested that overexpression of SBPase was an effective method for enhanncing salt tolerance in rice.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1075
Author(s):  
Ok Jin Hwang ◽  
Kyoungwhan Back

We investigated the relationship between the blue-light photoreceptor cryptochrome (CRY) and melatonin biosynthesis by generating RNA interference (RNAi) transgenic rice plants that suppress the cryptochrome 1b gene (CRY1b). The resulting CRY1b RNAi rice lines expressed less CRY1b mRNA, but not CRY1a or CRY2 mRNA, suggesting that the suppression is specific to CRY1b. The growth of CRY1b RNAi rice seedlings was enhanced under blue light compared to wild-type growth, providing phenotypic evidence for impaired CRY function. When these CRY1b RNAi rice plants were challenged with cadmium to induce melatonin, wild-type plants produced 100 ng/g fresh weight (FW) melatonin, whereas CRY1b RNAi lines produced 60 ng/g FW melatonin on average, indicating that melatonin biosynthesis requires the CRY photoreceptor. Due to possible feedback regulation, the expression of melatonin biosynthesis genes such as T5H, SNAT1, SNAT2, and COMT was elevated in the CRY1b RNAi lines compared to the wild-type plants. In addition, laminar angles decreased in the CRY1b RNAi lines via the suppression of brassinosteroid (BR) biosynthesis genes such as DWARF. The main cause of the BR decrease in the CRY1b RNAi lines seems to be the suppression of CRY rather than decreased melatonin because the melatonin decrease suppressed DWARF4 rather than DWARF.


2019 ◽  
Vol 61 (1) ◽  
pp. 88-104 ◽  
Author(s):  
Li Hua Cui ◽  
Mi Young Byun ◽  
Hyeong Geun Oh ◽  
Sung Jin Kim ◽  
Jungeun Lee ◽  
...  

Abstract Deschampsia antarctica is a Poaceae grass that has adapted to and colonized Antarctica. When D. antarctica plants were subjected to cold and dehydration stress both in the Antarctic field and in laboratory experiments, galactinol, a precursor of raffinose family oligosaccharides (RFOs) and raffinose were highly accumulated, which was accompanied by upregulation of galactinol synthase (GolS). The Poaceae monocots have a small family of GolS genes, which are divided into two distinct groups called types I and II. Type II GolSs are highly expanded in cold-adapted monocot plants. Transgenic rice plants, in which type II D. antarctica GolS2 (DaGolS2) and rice GolS2 (OsGolS2) were constitutively expressed, were markedly tolerant to cold and drought stress as compared to the wild-type rice plants. The RFO contents and GolS enzyme activities were higher in the DaGolS2- and OsGolS2-overexpressing progeny than in the wild-type plants under both normal and stress conditions. DaGolS2 and OsGolS2 overexpressors contained reduced levels of reactive oxygen species (ROS) relative to the wild-type plants after cold and drought treatments. Overall, these results suggest that Poaceae type II GolS2s play a conserved role in D. antarctica and rice in response to drought and cold stress by inducing the accumulation of RFO and decreasing ROS levels.


2011 ◽  
Vol 21 (4) ◽  
pp. 785-795 ◽  
Author(s):  
Shu-Ye Jiang ◽  
Ritu Bhalla ◽  
Rengasamy Ramamoorthy ◽  
Hong-Fen Luan ◽  
Prasanna Nori Venkatesh ◽  
...  

2014 ◽  
Vol 40 (7) ◽  
pp. 1190
Author(s):  
Yun-Peng WANG ◽  
Jing-Yong MA ◽  
Rui MA ◽  
Jian MA ◽  
Wen-Guo LIU

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