Correction to: A non-canonical Δ9-desaturase synthesizing palmitoleic acid identified in the thraustochytrid Aurantiochytrium sp. T66

Abstract Thraustochytrids are oleaginous marine eukaryotic microbes currently used to produce the essential omega-3 fatty acid docosahexaenoic acid (DHA, C22:6 n-3). To improve the production of this essential fatty acid by strain engineering, it is important to deeply understand how thraustochytrids synthesize fatty acids. While DHA is synthesized by a dedicated enzyme complex, other fatty acids are probably synthesized by the fatty acid synthase, followed by desaturases and elongases. Which unsaturated fatty acids are produced differs between different thraustochytrid genera and species; for example, Aurantiochytrium sp. T66, but not Aurantiochytrium limacinum SR21, synthesizes palmitoleic acid (C16:1 n-7) and vaccenic acid (C18:1 n-7). How strain T66 can produce these fatty acids has not been known, because BLAST analyses suggest that strain T66 does not encode any Δ9-desaturase-like enzyme. However, it does encode one Δ12-desaturase-like enzyme. In this study, the latter enzyme was expressed in A. limacinum SR21, and both C16:1 n-7 and C18:1 n-7 could be detected in the transgenic cells. Our results show that this desaturase, annotated T66Des9, is a Δ9-desaturase accepting C16:0 as a substrate. Phylogenetic studies indicate that the corresponding gene probably has evolved from a Δ12-desaturase-encoding gene. This possibility has not been reported earlier and is important to consider when one tries to deduce the potential a given organism has for producing unsaturated fatty acids based on its genome sequence alone. Key points • In thraustochytrids, automatic gene annotation does not always explain the fatty acids produced. • T66Des9 is shown to synthesize palmitoleic acid (C16:1 n-7). • T66des9 has probably evolved from Δ12-desaturase-encoding genes.

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Characterization of a Novel Acyl-ACP Δ9 Desaturase Gene Responsible for Palmitoleic Acid Accumulation in a Diatom Phaeodactylum tricornutum

Frontiers in Microbiology ◽

10.3389/fmicb.2020.584589 ◽

2020 ◽

Vol 11 ◽

Author(s):

Baoling Liu ◽

Yan Sun ◽

Wei Hang ◽

Xiaodan Wang ◽

Jinai Xue ◽

...

Keyword(s):

Fatty Acid ◽

Phaeodactylum Tricornutum ◽

Palmitoleic Acid ◽

Acyl Chain ◽

Marine Diatom ◽

Dimensional Structure ◽

Functional Domain ◽

Dna Encoding ◽

Practical Applications ◽

Δ9 Desaturase

Palmitoleic acid (16:1Δ9) possesses a double bond at the seventh carbon atom from methyl end of the acyl chain and belongs to unusual ω-7 monounsaturated fatty acids with broad applications in food, pharmaceuticals, cosmetics, biofuel, and other industries. This high-value fatty acid accumulates up to >40% of total lipid in the marine diatom Phaeodactylum tricornutum. The present study was conducted to determine the key gene responsible for 16:1Δ9 biosynthesis in this unicellular alga. A new full-length cDNA and genomic DNA encoding acyl-ACP Δ9 desaturase (PtAAD) were isolated from P. tricornutum cells. Expression levels of PtAAD gene under normal and stress culture conditions were both positively correlated with 16:1Δ9 accumulation, implying its potential role for fatty acid determination. Functional complementation assay of a yeast mutant strain BY4839 evidenced that PtAAD could restore the synthesis of unsaturated fatty acid, especially generating high levels of 16:1Δ9. Further transient expression of PtAAD gene in Nicotiana benthamiana leaves was accompanied by the accumulation of 16:1Δ9, which was absent from control groups. Three-dimensional structure modeling studies showed that functional domain of PtAAD contained three variant amino acids (F160, A223, and L156), which may narrow the space shape of substrate-binding cavity to ensure the entry of 16:0-ACP. Consistent with this prediction, the mutated version of PtAAD gene (F160L, A223T, and L156M) in N. benthamiana systems failed to accumulate 16:1Δ9, but increased levels of 18:1Δ9. Taken together, PtAAD exhibits a strong enzymatic activity and substrate preference for 16:0-ACP, acting as the key player for high biosynthesis and accumulation of 16:1Δ9 in this alga. These findings provide new insights for better understanding the palmitoleic acid and oil biosynthetic mechanism in P. tricornutum, indicating that PtAAD gene may have practical applications for enriching palmitoleic acid and oil yield in other commercial oleaginous algae and crops.

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Stearoyl-ACP Δ9 Desaturase 6 and 8 (GhA-SAD6 and GhD-SAD8) Are Responsible for Biosynthesis of Palmitoleic Acid Specifically in Developing Endosperm of Upland Cotton Seeds

Frontiers in Plant Science ◽

10.3389/fpls.2019.00703 ◽

2019 ◽

Vol 10 ◽

Cited By ~ 4

Author(s):

Baoling Liu ◽

Yan Sun ◽

Jinai Xue ◽

Xue Mao ◽

Xiaoyun Jia ◽

...

Keyword(s):

Upland Cotton ◽

Palmitoleic Acid ◽

Δ9 Desaturase ◽

Cotton Seeds

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Implications of Palmitoleic Acid (Palmitoleate) On Glucose Homeostasis, Insulin Resistance and Diabetes

Current Drug Targets ◽

10.2174/1389450117666151209120345 ◽

2017 ◽

Vol 18 (6) ◽

pp. 619-628 ◽

Cited By ~ 15

Author(s):

Everson Nunes ◽

Alex Rafacho

Keyword(s):

Insulin Resistance ◽

Glucose Homeostasis ◽

Palmitoleic Acid

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Comparative Study of Chemical Compositions and Antioxidant Capacities of Oils Obtained from 15 Macadamia (Macadamia integrifolia) Cultivars in China

Foods ◽

10.3390/foods10051031 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1031

Author(s):

Xixiang Shuai ◽

Taotao Dai ◽

Mingshun Chen ◽

Ruihong Liang ◽

Liqing Du ◽

...

Keyword(s):

Palmitoleic Acid ◽

Linear Regression Analysis ◽

Monounsaturated Fatty Acids ◽

Multiple Linear Regression Analysis ◽

Chemical Compositions ◽

Macadamia Integrifolia ◽

Antioxidant Capacities ◽

Squalene Content ◽

First Time ◽

Insight Into

The planting area of macadamia in China accounted for more than one third of the world’s planted area. The lipid compositions, minor components, and antioxidant capacities of fifteen varieties of macadamia oil (MO) in China were comparatively investigated. All varieties of MO were rich in monounsaturated fatty acids, mainly including oleic acid (61.74–66.47%) and palmitoleic acid (13.22–17.63%). The main triacylglycerols of MO were first time reported, including 19.2–26.1% of triolein, 16.4–18.2% of 1-palmitoyl-2,3-dioleoyl-glycerol, and 11.9–13.7% of 1-palmitoleoyl-2-oleoyl-3-stearoyl-glycerol, etc. The polyphenol, α-tocotrienol and squalene content varied among the cultivars, while Fuji (791) contained the highest polyphenols and squalene content. Multiple linear regression analysis indicated the polyphenols and squalene content positively correlated with the antioxidant capacity. This study can provide a crucial directive for the breeding of macadamia and offer an insight into industrial application of MO in China.

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Trans-palmitoleic Acid Reduces Adiposity via Increased Lipolysis in a Rodent Model of Diet-Induced Obesity

British Journal Of Nutrition ◽

10.1017/s0007114521001501 ◽

2021 ◽

pp. 1-24

Author(s):

L. Irasema Chávaro-Ortiz ◽

Brenda D. Tapia-Vargas ◽

Mariel Rico-Hidalgo ◽

Ruth Gutiérrez-Aguilar ◽

María E. Frigolet

Keyword(s):

Adipose Tissue ◽

Lipid Metabolism ◽

Visceral Adipose Tissue ◽

High Fat Diet ◽

Palmitoleic Acid ◽

Rodent Model ◽

Adipocyte Size ◽

High Fat ◽

Diet Induced Obesity ◽

Visceral Adipose

Abstract Obesity is defined as increased adiposity, which leads to metabolic disease. The growth of adipose tissue depends on its capacity to expand, through hyperplasia or hypertrophy, in order to buffer energy surplus. Also, during the establishment of obesity, adipose tissue expansion reflects adipose lipid metabolism (lipogenesis and/or lipolysis). It is well known that dietary factors can modify lipid metabolism promoting or preventing the development of metabolic abnormalities that concur with obesity. Trans-palmitoleic acid (TP), a biomarker of dairy consumption, has been associated with reduced adiposity in clinical studies. Thus, we aimed to evaluate the effect of TP over adiposity and lipid metabolism-related genes in a rodent model of diet-induced obesity (DIO). To fulfil this aim, we fed C57BL/6 mice with a Control or a High Fat diet, added with or without TP (3g/kg diet), during 11 weeks. Body weight and food intake were monitored, fat pads were weighted, histology of visceral adipose tissue was analysed, and lipid metabolism-related gene expression was explored by qPCR. Results show that TP consumption prevented weight gain induced by high fat diet, reduced visceral adipose tissue weight, and adipocyte size, while increasing the expression of lipolytic molecules. In conclusion, we show for the first time that TP influences adipose tissue metabolism, specifically lipolysis, resulting in decreased adiposity and reduced adipocyte size in a DIO mice model.

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