scholarly journals Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. Results Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. Conclusions Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.

2020 ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background: Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous.Results: Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents.Conclusions: Our study represents pioneering work on the characterization of HpDGAT2s by systematically integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.


2020 ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background: Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous.Results: Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents.Conclusions: Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.


2020 ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background: Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous.Results: Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents.Conclusions: Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.


2020 ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background: Haematococcus lacustris is an ideal source of astaxanthin (AST) which is stored at oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of the acyl-CoA-dependent TAG biosynthesis and are also considered as the crucial enzymes involving in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2 encoding genes in H. lacustris and only the HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis, especially possible roles in AST esterification, remains ambiguous.Results: Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capability to restore TAG synthesis in a TAG-deficient yeast strain (H1246) with the large difference in enzymatic activity. Fatty acids (FAs) profiles assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E except for HpDGAT2B preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and also showed polyunsaturated fatty acyl-CoAs (PUFAs) preference by feeding strategy. The over-expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. Interestingly, molecular docking analysis implied that HpDGAT2s structures contained AST binding sites, which provides strong evidence for AST esterification function in H. lacustris.Conclusions: Our study represents a pioneering work on the characterization of HpDGAT2s by systematically integrating expression pattern, AST/TAG accumulation, functional complementation, molecular docking, and over-expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, (4) offer target genes to modulate TAG biosynthesis by genetic engineering method, and (5) provide new evidence for HpDGAT2s roles in AST esterification.


2020 ◽  
Author(s):  
Hongli Cui ◽  
Chunchao Zhao ◽  
Wenxin Xu ◽  
Hongjiang Zhang ◽  
Wei Hang ◽  
...  

Abstract Background: Haematococcus lacustris is an ideal source of astaxanthin (AST) which is stored at oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of the acyl-CoA-dependent TAG biosynthesis and are also considered as the crucial enzymes involving in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2 encoding genes in H. lacustris and only the HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis, especially possible roles in AST esterification, remains ambiguous.Results: Five putative DGAT2 genes (HpDGAT2A, 2B, 2C, 2D, and 2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of HpDGAT2A, 2B, and 2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated HpDGAT2A, 2B, 2D, and 2E had the capability to restore TAG synthesis in a TAG-deficient yeast strain (H1246) with the large difference in enzymatic activity. Fatty acids (FAs) profiles assays revealed that HpDGAT2A, 2D, and 2E except for 2B preferred monounsaturated fatty acyl-CoA (MUFA) for TAG synthesis in yeast cells, and also showed polyunsaturated fatty acyl-CoA (PUFA) preference by feeding strategy. The over-expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFA and PUFA contents. Interestingly, molecular docking analysis implied that HpDGAT2s structures contained AST binding sites, which provides strong evidence for AST esterification function in H. lacustris.Conclusions: Our study represents a pioneering work on the characterization of HpDGAT2s by systematically integrating expression pattern, AST/TAG accumulation, functional complementation, molecular docking, and over-expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFA and PUFA, (4) offer target genes to modulate TAG biosynthesis by genetic engineering method, and (5) provide new evidence for HpDGAT2s roles in AST esterification.


Meta Gene ◽  
2021 ◽  
Vol 28 ◽  
pp. 100892
Author(s):  
Jingtian Wang ◽  
He Zhang ◽  
Shuang Xu ◽  
Ze Liu ◽  
Lu Yang ◽  
...  

2021 ◽  
Vol 22 (9) ◽  
pp. 4634
Author(s):  
Wenxuan Du ◽  
Junfeng Yang ◽  
Lin Ma ◽  
Qian Su ◽  
Yongzhen Pang

The calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) play important roles in plant signal transduction and response to abiotic stress. Plants of Medicago genus contain many important forages, and their growth is often affected by a variety of abiotic stresses. However, studies on the CBL and CIPK family member and their function are rare in Medicago. In this study, a total of 23 CBL and 58 CIPK genes were identified from the genome of Medicago sativa as an important forage crop, and Medicaog truncatula as the model plant. Phylogenetic analysis suggested that these CBL and CIPK genes could be classified into five and seven groups, respectively. Moreover, these genes/proteins showed diverse exon-intron organizations, architectures of conserved protein motifs. Many stress-related cis-acting elements were found in their promoter region. In addition, transcriptional analyses showed that these CBL and CIPK genes exhibited distinct expression patterns in various tissues, and in response to drought, salt, and abscisic acid treatments. In particular, the expression levels of MtCIPK2 (MsCIPK3), MtCIPK17 (MsCIPK11), and MtCIPK18 (MsCIPK12) were significantly increased under PEG, NaCl, and ABA treatments. Collectively, our study suggested that CBL and CIPK genes play crucial roles in response to various abiotic stresses in Medicago.


Heliyon ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. e06542
Author(s):  
Suharti ◽  
Gita Mahardika ◽  
Raissa ◽  
Laksmi Dewi ◽  
Heni Yohandini ◽  
...  

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