scholarly journals Overexpression of TaCOMT Improves Melatonin Production and Enhances Drought Tolerance in Transgenic Arabidopsis

2019 ◽  
Vol 20 (3) ◽  
pp. 652 ◽  
Author(s):  
Wen-Jing Yang ◽  
Yong-Tao Du ◽  
Yong-Bin Zhou ◽  
Jun Chen ◽  
Zhao-Shi Xu ◽  
...  

Melatonin (N-acetyl-5-methoxytryptamine) is involved in many developmental processes and responses to various abiotic stresses in plants. Most of the studies on melatonin focus on its functions and physiological responses in plants, while its regulation mechanism remains unknown. Caffeic acid 3-O-methyltransferase (COMT) functions at a key step of the biosynthesis process of melatonin. In this study, a COMT-like gene, TaCOMT (Traes_1AL_D9035D5E0.1) was identified in common wheat (Triticum aestivum L.). Transient transformation in wheat protoplasts determined that TaCOMT is localized in cytoplasm. TaCOMT in wheat was induced by drought stress, gibberellin (GA)3 and 3-Indoleacetic acid (IAA), but not by ABA. In TaCOMT transgenic Arabidopsis, melatonin contents were higher than that in wild type (WT) plants. Under D-Mannitol treatment, the fresh weight of the transgenic Arabidopsis was significantly higher than WT, and transgenic lines had a stronger root system compared to WT. Drought tolerance assays in pots showed that the survival rate of TaCOMT-overexpression lines was significantly higher than that of WT lines. this phenotype was similar to that the WT lines treated with melatonin under drought condition. In addition, the TaCOMT transgenic lines had higher proline content and lower malondialdehyde (MDA) content compared to WT lines after drought treatment. These results indicated that overexpression of the wheat TaCOMT gene enhances drought tolerance and increases the content of melatonin in transgenic Arabidopsis. It could be one of the potential genes for agricultural applications.

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 161 ◽  
Author(s):  
Muhammad Junaid Rao ◽  
Yuantao Xu ◽  
Xiaomei Tang ◽  
Yue Huang ◽  
Jihong Liu ◽  
...  

CYTOCHROME P450s genes are a large gene family in the plant kingdom. Our earlier transcriptome data revealed that a CYTOCHROME P450 gene of Citrus sinensis (CsCYT75B1) was associated with flavonoid metabolism and was highly induced after drought stress. Here, we characterized the function of CsCYT75B1 in drought tolerance by overexpressing it in Arabidopsis thaliana. Our results demonstrated that the overexpression of the CsCYT75B1 gene significantly enhanced the total flavonoid contents with increased antioxidant activity in transgenic Arabidopsis. The gene expression results showed that several genes that are responsible for the biosynthesis of antioxidant flavonoids were induced by 2–12 fold in transgenic Arabidopsis lines. After 14 days of drought stress, all transgenic lines displayed an enhanced tolerance to drought stress along with accumulating antioxidant flavonoids with lower superoxide radicals and reactive oxygen species (ROS) than wild type plants. In addition, drought-stressed transgenic lines possessed higher antioxidant enzymatic activities than wild type transgenic lines. Moreover, the stressed transgenic lines had significantly lower levels of electrolytic leakage than wild type transgenic lines. These results demonstrate that the CsCYT75B1 gene of sweet orange functions in the metabolism of antioxidant flavonoid and contributes to drought tolerance by elevating ROS scavenging activities.


2012 ◽  
Vol 137 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Cong Li ◽  
Lie-Bao Han ◽  
Xunzhong Zhang

Drought stress is one of the major limiting factors for plant growth and development. The mechanism of drought tolerance has not been well understood. This study was designed to investigate proline and antioxidant metabolism associated with drought tolerance in transgenic tobacco (Nicotiana tabacum) plants overexpressing the OjERF gene relative to wild-type (WT) plants. The OjERF gene was isolated from mondo grass (Ophiopogon japonicus). The OjERF gene, driven by the CaMV35S promoter, was introduced into tobacco through agrobacterium (Agrobacterium tumefaciens)-mediated transformation. Five transgenic lines were regenerated, of which transgenic Line 5 (GT5) and Line 6 (GT6) were used to examine drought tolerance in comparison with WT plants in a growth chamber. Drought stress caused an increase in leaf malondialdehyde (MDA) and electrolyte leakage (EL), proline content, superoxide dismutase (SOD), and catalase (CAT) activity in both transgenic lines and WT plants. However, the transgenic lines had lower MDA content and EL and higher proline content, SOD and CAT activity relative to WT under drought stress. The activities of SOD and CAT were also greater in the transgenic lines relative to WT plants under well-watered conditions (Day 0). The OjERF activated the expression of stress-relative genes, including NtERD10B, NtERD10C, NtERF5, NtSOD, and NtCAT1 in tobacco plants. The results of this study suggest that the OjERF gene may confer drought stress tolerance through upregulating proline and antioxidant metabolism.


2019 ◽  
Vol 20 (14) ◽  
pp. 3573 ◽  
Author(s):  
Zhenghua He ◽  
Jinfeng Wu ◽  
Xiaopeng Sun ◽  
Mingqiu Dai

As the core components of abscisic acid (ABA) signal pathway, Clade A PP2C (PP2C-A) phosphatases in ABA-dependent stress responses have been well studied in Arabidopsis. However, the roles and natural variations of maize PP2C-A in stress responses remain largely unknown. In this study, we investigated the expression patterns of ZmPP2C-As treated with multiple stresses and generated transgenic Arabidopsis plants overexpressing most of the ZmPP2C-A genes. The results showed that the expression of most ZmPP2C-As were dramatically induced by multiple stresses (drought, salt, and ABA), indicating that these genes may have important roles in response to these stresses. Compared with wild-type plants, ZmPP2C-A1, ZmPP2C-A2, and ZmPP2C-A6 overexpression plants had higher germination rates after ABA and NaCl treatments. ZmPP2C-A2 and ZmPP2C-A6 negatively regulated drought responses as the plants overexpressing these genes had lower survival rates, higher leaf water loss rates, and lower proline accumulation compared to wild type plants. The natural variations of ZmPP2C-As associated with drought tolerance were also analyzed and favorable alleles were detected. We widely studied the roles of ZmPP2C-A genes in stress responses and the natural variations detected in these genes have the potential to be used as molecular markers in genetic improvement of maize drought tolerance.


2020 ◽  
Vol 21 (3) ◽  
pp. 996 ◽  
Author(s):  
Fuai Sun ◽  
Haoqiang Yu ◽  
Jingtao Qu ◽  
Yang Cao ◽  
Lei Ding ◽  
...  

The BRI1-EMS suppressor 1 (BES1)/brassinazole-resistant 1 (BZR1) transcription factors, key components in the brassinosteroid signaling pathway, play pivotal roles in plant growth and development. However, the function of BES1/BZR1 in crops during stress response remains poorly understood. In the present study, we characterized ZmBES1/BZR1-5 from maize, which was localized to the nucleus and was responsive to abscisic acid (ABA), salt and drought stresses. Heterologous expression of ZmBES1/BZR1-5 in transgenic Arabidopsis resulted in decreased ABA sensitivity, facilitated shoot growth and root development, and enhanced salt and drought tolerance with lower malondialdehyde (MDA) content and relative electrolyte leakage (REL) under osmotic stress. The RNA sequencing (RNA-seq) analysis revealed that 84 common differentially expressed genes (DEGs) were regulated by ZmBES1/BZR1-5 in transgenic Arabidopsis. Subsequently, gene ontology and KEGG pathway enrichment analyses showed that the DEGs were enriched in response to stress, secondary metabolism and metabolic pathways. Furthermore, 30 DEGs were assigned to stress response and possessed 2–15 E-box elements in their promoters, which could be potentially recognized and bound by ZmBES1/BZR1-5. Taken together, our results reveal that the ZmBES1/BZR1-5 transcription factor positively regulates salt and drought tolerance by binding to E-box to induce the expression of downstream stress-related genes. Therefore, our study contributes to the better understanding of BES1/BZR1 function in the stress response of plants.


2021 ◽  
Author(s):  
Luhua Li ◽  
Chang An ◽  
Zhongni Wang ◽  
Fumin Xiong ◽  
Yingxi Wang ◽  
...  

Abstract Anthocyanidin synthase (ANS) is involved in the synthesis of anthocyanins, which are important phytonutrients because of their beneficial effects on human health. Here, we identified ANS-6D of purple-colored Triticum aestivum L. cv. Guizi 1 (Gz) that is involved in leaf senescence through the abscisic acid (ABA) mediated chlorophyll degradation pathway in tobacco. After characterizing the leaf-senescence phenotype in GzANS-6D overexpression (OxGzANS-6D) lines, we found that the increased anthocyanin accumulation and decreased chlorophyll content in OxGzANS-6D lines were closely correlated with the expression levels of anthocyanin synthesis-related structural genes and senescence marker genes, as well as the accumulation of reactive oxygen species. The endogenous ABA content increased and ethylene content decreased in OxGzANS-6D transgenic lines compared with wild type. Additionally, the levels of the abscisic acid-responsive transcription factors ABF1 and ABF2, as well as those of chlorophyll degradation-related genes (PAO, NYC, SGR and CHL), were significantly higher in OxGzANS-6D transgenic lines than in wild type. Furthermore, we found that GzABF1 and NtABF1 binds to the promoter of GzANS-6D, and NtABF2 binds to the promoter of NtSGR. Thus, GzANS-6D participated in leaf senescence through ABA-mediated chlorophyll degradation, and ABF1/2 play important role in GzANS-6D functions.


2020 ◽  
Author(s):  
Shumin Li ◽  
Nan Chen ◽  
Fangfang Li ◽  
Fangming Mei ◽  
Zhongxue Wang ◽  
...  

Abstract Background: Many studies in Arabidopsis and rice have demonstrated that HD-Zip transcription factors play important roles in plant development and responses to abiotic stresses. Although common wheat (Triticum aestivum L.) is one of the most widely cultivated and consumed food crops in the world, the function of the HD-Zip proteins in wheat is still largely unknown. Results: To explore the potential biological functions of HD-Zip genes in wheat, we performed a bioinformatics and gene expression analysis of the HD-Zip family. We identified 113 HD-Zip members from wheat and classified them into four subfamilies (I-IV) based on phylogenic analysis against proteins from Arabidopsis, rice, and maize. Most HD-Zip genes are represented by two to three homeoalleles in wheat, which are named as TaHDZX_ZA, TaHDZX_ZB, or TaHDZX_ZD, where X denotes the gene number and Z the wheat chromosome on which it is located. TaHDZs in the same subfamily have similar protein motifs and intron/exon structures. The expression profiles of TaHDZ genes were analysed in different tissues, at different stages of vegetative growth, during seed development, and under drought stress. We found that most TaHDZ genes, especially those in subfamilies I and II, were induced by drought stress, suggesting the potential importance of subfamily I and II TaHDZ members in the responses to abiotic stress. Compared with wild-type (WT) plants, transgenic Arabidopsis plants overexpressing TaHDZ5-6A displayed enhanced drought tolerance, lower water loss rates, higher survival rates, and higher proline content under drought conditions. Additionally, the transcriptome analysis identified a number of differentially expressed genes between 35S::TaHDZ5-6A transgenic and wild-type plants, many of which are involved in stress response. Conclusions: Our results will facilitate further functional analysis of wheat HD-Zip genes, and also indicate that TaHDZ5-6A may participate in regulating the plant response to drought stress. Our experiments show that TaHDZ5-6A holds great potential for genetic improvement of abiotic stress tolerance in crops.


2021 ◽  
Author(s):  
nikang ◽  
bang

Abstract Phospholipase D (PLD) is a crucial enzyme participated in membrane phospholipid catabolism. In this study, to explore the function of CbPLDγ in drought stress, a CbPLDγ gene, which is a part of CbPLD gene family and from Chorispora bungeana (C. bungeana) was cloned and encoded a protein of 859 amino acids with a calculated molecular weight of 96.3 kDa and with a PI(Isoionic Point) of 7.88. Real-time quantitative PCR (RT-qPCR) and Beta-glucuronidase (GUS) assay showed that CbPLDγ was accumulated dominantly in roots and hypocotyls. Compared with the control, CbPLDγ was positively responsed to the low temperature, salt, mannitol, and exogenous ABA. Subcellular localization analysis showed that the CbPLDγ was localized in the cell membrane. CbPLDγ-overexpression Arabidopsis under drought stress showed higher relative expression of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as highe content of proline, soluble proteion and soluble sugar. However, H2O2, malonaldehyde (MDA) content and electrolyte leakage (EL) were lower than wild-type Arabidopsis. These indicated that CbPLDγ was involved in the drought tolerance, and overexpression of CbPLDγ enhanced the drought tolerance in Arabidopsis. This is the first report about cloning and characterizing the gene of CbPLDγ from C. bungeana. It laid a foundation for further research and improvement of the PLD gene family of C. bungeana.


2019 ◽  
Author(s):  
Shumin Li ◽  
Nan Chen ◽  
Fangfang Li ◽  
Fangming Mei ◽  
Zhongxue Wang ◽  
...  

Abstract Abstract Background: Many studies in Arabidopsis and rice have demonstrated that HD-Zip transcription factors play important roles in plant development and responses to abiotic stresses. Although common wheat (Triticum aestivum L.) is one of the most widely cultivated and consumed food crops in the world, the function of the HD-Zip proteins in wheat is still largely unknown. Results: To explore the potential biological functions of HD-Zip genes in wheat, we performed a bioinformatics and gene expression analysis of the HD-Zip family. We identified 113 HD-Zip members from wheat and classified them into four subfamilies (I-IV) based on phylogenic analysis against proteins from Arabidopsis, rice, and maize. Most HD-Zip genes are represented by two to three homeoalleles in wheat, which are named as TaHDZX_ZA, TaHDZX_ZB, or TaHDZX_ZD, where X denotes the gene number and Z the wheat chromosome on which it is located. TaHDZs in the same subfamily have similar protein motifs and intron/exon structures. The expression profiles of TaHDZ genes were analysed in different tissues, at different stages of vegetative growth, during seed development, and under drought stress. We found that most TaHDZ genes, especially those in subfamilies I and II, were induced by drought stress, suggesting the potential importance of subfamily I and II TaHDZ members in the responses to abiotic stress. Compared with wild-type (WT) plants, transgenic Arabidopsis plants overexpressing TaHDZ5-6A displayed enhanced drought tolerance, lower water loss rates, higher survival rates, and higher proline content under drought conditions. Additionally, the transcriptome analysis identified a number of differentially expressed genes between 35S::TaHDZ5-6A transgenic and wild-type plants, many of which are involved in stress response. Conclusions: Our results will facilitate further functional analysis of wheat HD-Zip genes, and also indicate that TaHDZ5-6A may participate in regulating the plant response to drought stress. Our experiments show that TaHDZ5-6A holds great potential for genetic improvement of abiotic stress tolerance in crops.


2020 ◽  
Vol 21 (4) ◽  
pp. 1198 ◽  
Author(s):  
Deguo Han ◽  
Man Du ◽  
Zhengyi Zhou ◽  
Shuang Wang ◽  
Tiemei Li ◽  
...  

NAC (no apical meristem (NAM), Arabidopsis thaliana transcription activation factor (ATAF1/2) and cup shaped cotyledon (CUC2)) transcription factors play crucial roles in plant development and stress responses. Nevertheless, to date, only a few reports regarding stress-related NAC genes are available in Malus baccata (L.) Borkh. In this study, the transcription factor MbNAC25 in M. baccata was isolated as a member of the plant-specific NAC family that regulates stress responses. Expression of MbNAC25 was induced by abiotic stresses such as drought, cold, high salinity and heat. The ORF of MbNAC25 is 1122 bp, encodes 373 amino acids and subcellular localization showed that MbNAC25 protein was localized in the nucleus. In addition, MbNAC25 was highly expressed in new leaves and stems using real-time PCR. To analyze the function of MbNAC25 in plants, we generated transgenic Arabidopsis plants that overexpressed MbNAC25. Under low-temperature stress (4 °C) and high-salt stress (200 mM NaCl), plants overexpressing MbNAC25 enhanced tolerance against cold and drought salinity conferring a higher survival rate than that of wild-type (WT). Correspondingly, the chlorophyll content, proline content, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly increased, while malondialdehyde (MDA) content was lower. These results indicated that the overexpression of MbNAC25 in Arabidopsis plants improved the tolerance to cold and salinity stress via enhanced scavenging capability of reactive oxygen species (ROS).


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Chao Cheng ◽  
Shutong Hu ◽  
Yun Han ◽  
Di Xia ◽  
Bang-Lian Huang ◽  
...  

Abstract Background Cuticular wax plays important role in protecting plants from drought stress. In Arabidopsis WRI4 improves drought tolerance by regulating the biosynthesis of fatty acids and cuticular wax. Cyperus esculentus (yellow nutsedge) is a tough weed found in tropical and temperate zones as well as in cooler regions. In the current study, we report the molecular cloning of a WRI4-like gene from Cyperus esculentus and its functional characterization in Arabidopsis. Results Using RACE PCR, full-length WRI-like gene was amplified from yellow nutsedge. Phylogenetic analyses and amino acid comparison suggested it to be a WRI4-like gene. According to the tissue-specific expression data, the highest expression of WRI4-like gene was found in leaves, followed by roots and tuber. Transgenic Arabidopsis plants expressing nutsedge WRI4-like gene manifested improved drought stress tolerance. Transgenic lines showed significantly reduced stomatal conductance, transpiration rate, chlorophyll leaching, water loss and improved water use efficiency (WUE). In the absence of drought stress, expression of key genes for fatty acid biosynthesis was not significantly different between transgenic lines and WT while that of cuticular wax biosynthesis genes was significantly higher in transgenic lines than WT. The PEG-simulated drought stress significantly increased expression of key genes for fatty acid as well as wax biosynthesis in transgenic Arabidopsis lines but not in WT plants. Consistent with the gene expression data, cuticular wax load and deposition was significantly higher in stem and leaves of transgenic lines compared with WT under control as well as drought stress conditions. Conclusions WRI4-like gene from Cyperus esculentus improves drought tolerance in Arabidopsis probably by promoting cuticular wax biosynthesis and deposition. This in turn lowers chlorophyll leaching, stomatal conductance, transpiration rate, water loss and improves water use efficiency under drought stress conditions. Therefore, CeWRI4-like gene could be a good candidate for improving drought tolerance in crops.


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