Expression ofCamelinaWRINKLED1 Isoforms Rescue the Seed Phenotype of theArabidopsis wri1Mutant and Increase the Triacylglycerol Content in Tobacco Leaves.
Triacylglycerol (TAG) is an energy-rich reserve in plant seeds that is composed of glycerol esters with three fatty acids. Since TAG can be used as a feedstock for the production of biofuels and bio-chemicals, producing TAGs in vegetative tissue is an alternative way of meeting the increasing demand for its usage. TheWRINKLED1(WRI1) gene is a well-established key transcriptional regulator involved in the upregulation of fatty acid biosynthesis in developing seeds. WRI1s fromArabidopsisand several other crops have been previously employed for increasing TAGs in seed and vegetative tissues. In the present study, we first identified three functionalCsWRI1genes (CsWRI1A. B, andC) from theCamelinaoil crop and tested their ability to induce TAG synthesis in leaves. The amino acid sequences ofCsWRI1sexhibited more than 90% identity with those ofArabidopsis WRI1. The transcript levels of the threeCsWRI1genes showed higher expression levels in developing seeds than in vegetative and floral tissues. When theCsWRI1A. B, orCwas introduced intoArabidopsis wri1-3loss-of-function mutant, the fatty acid content was restored to near wild-type levels and percentages of the wrinkled seeds were remarkably reduced in the transgenic lines relative towri1-3mutant line. In addition, the fluorescent signals of the enhanced yellow fluorescent protein (eYFP) fused to theCsWRI1genes were observed in the nuclei ofNicotiana benthamianaleaf epidermal cells. Nile red staining indicated that the transient expression ofCsWRI1A. B, orCcaused an enhanced accumulation of oil bodies inN. benthamianaleaves. The levels of TAGs was higher by approximately 2.5- to 4.0-fold inN. benthamianafresh leaves expressingCsWRI1genes than in the control leaves. These results suggest that the threeCamelinaWRI1s can be used as key transcriptional regulators to increase fatty acids in biomass.
Department of Bioenergy Science and Technology, Chonnam National University Gwangju, South Korea.
Dahee
D
An
Department of Bioenergy Science and Technology, Chonnam National University Gwangju, South Korea.
Hyojin
H
Kim
Department of Bioenergy Science and Technology, Chonnam National University Gwangju, South Korea.
Seulgi
S
Ju
Department of Bioenergy Science and Technology, Chonnam National University Gwangju, South Korea.
Young Sam
YS
Go
Department of Bioindustry and Bioresource Engineering, Plant Engineering Research Institute, Sejong University Seoul, South Korea.
Hyun Uk
HU
Kim
Department of Bioenergy Science and Technology, Chonnam National University Gwangju, South Korea.
Mi Chung
MC
Suh
Camelina sativa; WRINKLED1; fatty acid; leaves; oil; triacylglycerol