scholarly journals Overexpression of Chalcone Synthase Improves Flavonoid Accumulation and Drought Tolerance in Tobacco

Author(s):  
Ben Hu ◽  
Heng Yao ◽  
Xiaojun Peng ◽  
Ran Wang ◽  
Feng Li ◽  
...  

Flavonoids are major secondary metabolites in plants, which play important roles in maintaining the cellular redox balance in cells. Chalcone synthase (CHS) is the key enzyme in the flavonoids biosynthesis pathway, and has been proved to monitor the changes to drought stress tolerance. In this work, we overexpressed a CHS gene in tobacco (Nicotiana tabacum). The transgenic tobacco plants were more tolerant than the control plants to drought stress. The transcription levels of the key genes involved in the flavonoids pathway and the contents of seven flavonoids were also significantly raised in the transgenic tobacco plants. In addition, overexpression of the CHS gene lead to a lower concentration of the oxidative stress product malondialdehyde. Overall, the NtCHS gene studied in this work was considered as a candidate gene for genetic engineering to enhance drought tolerance of plants and improve response to oxidative stress.

2020 ◽  
Author(s):  
Ben Hu ◽  
Heng Yao ◽  
Yulong Gao ◽  
Ran Wang ◽  
Feng Li ◽  
...  

Abstract Flavonoids are important secondary metabolites in plants that play important roles in maintaining the cellular redox balance of cells. Chalcone synthase (CHS) is the key enzyme in the flavonoid biosynthesis pathway and has been found to monitor changes due to drought stress tolerance. In this study, a CHS gene in tobacco ( Nicotiana tabacum ) was overexpressed. Results revealed that transgenic tobacco plants were more tolerant than control plants to drought stress. Transcription levels of the key genes involved in the flavonoid pathway and the contents of seven flavonoids significantly increased in transgenic tobacco plants ( p < 0.01). Overexpression of the CHS gene led to lower concentrations of the oxidative stress product, malondialdehyde (MDA). Additionally, 11 CHS family genes were mined from the tobacco genome. Based on the phylogenetic tree, these genes split into two groups with eight genes clustered together with the bona fide Arabidopsis CHS gene, suggesting that those tobacco genes are CHS genes. Further phylogenetic analyses indicated that the tobacco CHS genes grouped further into three independent clades with the cloned tobacco CHS gene located within Clade iii. The tobacco CHS family genes exhibited a highly conserved CDS length, pI, and molecular weight of the encoded peptides. All CHS peptides contained two conserved domains, and the genes harbored two or three exons. Based on the results of this study, the NtCHS gene is considered a possible candidate gene for genetically engineering enhanced drought tolerance and improved responses to oxidative stress in plants.


Author(s):  
Ben Hu ◽  
Heng Yao ◽  
Yulong Gao ◽  
Ran Wang ◽  
Feng Li ◽  
...  

Abstract Background: Flavonoids are important secondary metabolites in plants that play important roles in maintaining the cellular redox balance of cells. Chalcone synthase (CHS) is the key enzyme in the flavonoid biosynthesis pathway and has been found to monitor changes due to drought stress tolerance.Results: In this study, a CHS gene in tobacco (Nicotiana tabacum) was overexpressed. Results revealed that transgenic tobacco plants were more tolerant than control plants to drought stress. Transcription levels of the key genes involved in the flavonoid pathway and the contents of seven flavonoids significantly increased in transgenic tobacco plants (p < 0.01). Overexpression of the CHS gene led to lower concentrations of the oxidative stress product, malondialdehyde (MDA). Additionally, 11 CHS family genes were mined from the tobacco genome. Based on the phylogenetic tree, these genes split into two groups with eight genes clustered together with the bona fide Arabidopsis CHS gene, suggesting that those tobacco genes are CHS genes. Further phylogenetic analyses indicated that the tobacco CHS genes grouped further into three independent clades with the cloned tobacco CHS gene located within Clade iii. The tobacco CHS family genes exhibited a highly conserved CDS length, pI, and molecular weight of the encoded peptides. All CHS peptides contained two conserved domains, and the genes harbored two or three exons.Conclusions: Based on the results of this study, the NtCHS gene is considered a possible candidate gene for genetically engineering enhanced drought tolerance and improved responses to oxidative stress in plants.


Author(s):  
Ai-Hua Wang ◽  
Lan Yang ◽  
Xin-Zhuan Yao ◽  
Xiao-Peng Wen

AbstractPhosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.


Author(s):  
L. Slooten ◽  
W. van Camp ◽  
S. Kushnir ◽  
J. Botterman ◽  
M. van Montagu ◽  
...  

2021 ◽  
Author(s):  
Alireza Abbasi ◽  
Meysam Malekpour ◽  
Sajjad Sobhanverdi

Abstract Expansins are cell wall proteins that, due to changes in pH, causing the expansion of the cell walls. In this study, a previously gene construct designed based on a root-specific gene, AtEXPA18, was utilized to assess its potential roles on different morphological, physiological, and cellular levels of generated transgenic tobacco plants in response to moderate and severe drought stress. AtEXPA18 gene was successfully transferred to the tobacco plants through an agrobacterium-mediate transformation system. Upon obtaining the second generation, tobacco transgenic plants were confirmed by conventional polymerase chain reaction (PCR) technique alongside reverse transcription PCR (RT-PCR) using specific primers. Under drought stress, the transgenic lines showed remarkable growth and significantly improved based on morphological traits such as height and stem diameter, leaf area, leaf number, root dry weight, and Abscisic acid (ABA) levels of leaves compared control plants. As a result, the Cytokinin content of transgenic plants has increased under severe stress levels. Notably, the area's expansion for abaxial epidermal cells under the microscope confirmed in transgene cells compared with the -transgene cells. These results, altogether, could support the AtEXPA18 gene implication in cell expansion and improving tolerance capacity of transgenic crops under drought stress.


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