Genetic enhancement of oil content in potato tuber (Solanum tuberosum L.) through an integrated metabolic engineering strategy.
Potato tuber is a high yielding food crop known for its high levels of starch accumulation but only negligible levels of triacylglycerol (TAG). In this study, we evaluated the potential for lipid production in potato tubers by simultaneously introducing three transgenes, including WRINKLED 1 (WRI1), DIACYLGLYCEROL ACYLTRANSFERASE 1 (DGAT1) and OLEOSIN under the transcriptional control of tuber-specific (patatin) and constitutive (CaMV-35S) promoters. This coordinated metabolic engineering approach resulted in over a 100-fold increase in TAG accumulation to levels up to 3.3% of tuber dry weight (DW). Phospholipids and galactolipids were also found to be significantly increased in the potato tuber. The increase of lipids in these transgenic tubers was accompanied by a significant reduction in starch content and an increase in soluble sugars. Microscopic examination revealed that starch granules in the transgenic tubers had more irregular shapes and surface indentations when compared with the relatively smooth surfaces of wild-type starch granules. Ultrastructural examination of lipid droplets showed their close proximity to endoplasmic reticulum and mitochondria, which may indicate a dynamic interaction with these organelles during the processes of lipid biosynthesis and turnover. Increases in lipid levels were also observed in the transgenic potato leaves, likely due to the constitutive expression of DGAT1 and incomplete tuber specificity of the patatin promoter. This study represents an important proof-of-concept demonstration of oil increase in tubers and provides a model system to further study carbon reallocation during development of nonphotosynthetic underground storage organs.
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Qing
Q
Liu
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.|College of Horticulture & Landscape Architecture, Southwest University, Chongqing, China.
Qigao
Q
Guo
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.|National University of Science and Technology (NUST) Islamabad, Islamabad, Pakistan.
Sehrish
S
Akbar
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.|State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.
Yao
Y
Zhi
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Anna
A
El Tahchy
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Madeline
M
Mitchell
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Zhongyi
Z
Li
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Pushkar
P
Shrestha
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Thomas
T
Vanhercke
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Jean-Philippe
JP
Ral
College of Horticulture & Landscape Architecture, Southwest University, Chongqing, China.
Guolu
G
Liang
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Ming-Bo
MB
Wang
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Rosemary
R
White
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Philip
P
Larkin
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
Surinder
S
Singh
Commonwealth Scientific and Industrial Research Organisation Agriculture, Black Mountain, ACT, Australia.
James
J
Petrie
D002241:Carbohydrates / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D038983:Galactolipids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D017343:Genes, Plant; D024861:Genetic Enhancement / Q000379:methods*; D060847:Metabolic Engineering / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D010743:Phospholipids / Q000378:metabolism; D010938:Plant Oils / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D035281:Plant Tubers / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011198:Solanum tuberosum / Q000166:cytology / Q000235:genetics*; D013213:Starch / Q000032:analysis / Q000378:metabolism; D014170:Transformation, Genetic; D014280:Triglycerides / Q000378:metabolism
D002241:Carbohydrates; D005227:Fatty Acids; D038983:Galactolipids; D010743:Phospholipids; D010938:Plant Oils; D010940:Plant Proteins; D014280:Triglycerides; C007388:digalactosyldiacylglycerol; D013213:Starch

DGAT1
; 
Solanum tuberosum
; 
WRI1
; oleosin; potato; triacylglycerol