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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Commodity Utilization Research » Research » Publications at this Location » Publication #355459
Research Project: Increasing the Value of Cottonseed

Location: Commodity Utilization Research

Title: Boosting C16 fatty acid biosynthesis of Escherichia coli, yeast and tobacco by tung tree (Vernicia fordii Hemsl.) beta-hydroxyacyl-acyl carrier protein dehydratase gene

Author
item LIU, MEILAN - Central South University Of Forestry And Technology
item LONG, HONGXU - Central South University Of Forestry And Technology
item LI, WENYING - Central South University Of Forestry And Technology
item SHI, MINGWANG - Henan Institute Of Science And Technology
item Cao, Heping
item ZHANG, LIN - Central South University Of Forestry And Technology
item TAN, XIAOFENG - Central South University Of Forestry And Technology

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2018
Publication Date: 1/1/2019
Citation: Liu, M., Long, H., Li, W., Shi, M., Cao, H., Zhang, L., Tan, X. 2019. Boosting C16 fatty acid biosynthesis of Escherichia coli, yeast and tobacco by tung tree (Vernicia fordii Hemsl.) beta-hydroxyacyl-acyl carrier protein dehydratase gene. Industrial Crops and Products. 127:46-54. https://doi.org/10.1016/j.indcrop.2018.10.067.
DOI: https://doi.org/10.1016/j.indcrop.2018.10.067

Interpretive Summary: Tung tree is an economically important tree. Tung seeds contain approximately 60% oil (dry weight basis) with about 80 mole % a-eleostearic acid. Tung oil is readily oxidized because of the three unique conjugated double bonds in eleostearic acid. Dried tung oil is impervious to heat, moisture, dust and many chemical challenges. Tung oil does not darken with age, making it a widely used drying ingredient in paints, varnishes, coatings and finishes. This manuscript reports the characterization of tung tree beta-hydroxyacyl-acyl carrier protein dehydratase (HAD), an important enzyme in the type-II fatty acid synthase system, functions in forming the basic carbon chain skeleton of fatty acids. HAD is one of the most important synthases in determining the oily characters of hydrocarbons. Many plants and bacterial HAD homologs have been characterized to gain insight into fatty acid synthase system. However, HAD has not been reported to date in tung tree. In this study, we isolated tung tree HAD. VfHAD showed relatively higher expression levels in young leaves, petals, and stigma of tung tree. During seed development, VfHAD expression paralleled oil synthesis with a peak at 20 weeks after flowering when oil rapidly accumulated. VfHAD was heterologously expressed in Escherichia coli, yeast, and tobacco plants. Over-expression of HAD alter their respective fatty acid compositions, especially by increasing the proportion of C16 fatty acid. These results imply that VfHAD may specifically promote the biosynthesis of C16 fatty acid. The information may be useful for tung oil engineering in transgenic plants.

Technical Abstract: Beta-hydroxyacyl-acyl carrier protein dehydratase (HAD), an important enzyme in the type-II fatty acid synthase system, functions in forming the basic carbon chain skeleton of fatty acids. HAD is one of the most important synthases in determining the oily characters of hydrocarbons. Many plants and bacterial HAD homologs have been characterized to gain insight into fatty acid synthase system. However, HAD has not been reported to date in tung tree (Vernicia fordii), which represents one of the four major sources of woody oils in China. In this study, the tung tree HAD (GenBank KU358903) was isolated and named VfHAD. VfHAD shared all essential catalytic sites and the characteristic “hot-dog” structure of FabZ proteins with HAD homologs. VfHAD showed relatively higher expression levels in different mitotically active tung tree tissues, such as young leaves, petals, and stigma. During seed development, VfHAD expression paralleled oil synthesis with a peak at 20 weeks after flowering when oil rapidly accumulated. VfHAD was heterologously expressed in Escherichia coli, yeast, and tobacco plants, and it could potentially alter their respective fatty acid compositions, especially by increasing the proportion of C16 fatty acid. These results imply that VfHAD may specifically promote the biosynthesis of C16 fatty acid.