Increased levels of erucic acid in Brassica carinata by co-suppression and antisense repression of the endogenous FAD2 gene.
Erucic acid and its derivatives represent important industrial feedstock compounds, and there is an increasing demand for the production of high erucate oils in this regard. Our goal therefore, is to develop high erucic acid (HEA) Brassicaceae lines with increased proportions of erucic acid and very long-chain fatty acids (VLCFAs). We proposed that oleate availability may be a rate-limiting factor in the biosynthesis of erucic acid. We have tried to address this question by manipulating the expression of the endogenous FAD2 gene in B. carinata using co-supression and antisense approaches. Both methods resulted in transgenic lines exhibiting decreased proportions of polyunsaturated C18 fatty acids (18:2+18:3) and concomitant and significantly increased proportions of 18:1, 22:1 and total VLCFAs. Co-suppressed FAD2 B. carinata lines exhibited 3-18% decreases in 18:2, 22-49% decreases in 18:3 and significantly increased proportions of 18:1 (36-99%), 22:1 (12-27%) and VLCFAs (6-15%). Transgenic B. carinata lines developed using an antisense FAD2 approach exhibited decreased proportions of 18:2 and 18:3 (9-39% and 33-48%, respectively) and significantly increased proportions of 18:1 (54-130%), 22:1 (5-19%) and VLCFAs (6-21%). The possibility of using these approaches to produce prototype transgenic germplasm of the Brassicaceae accumulating seed oils with improved proportions of erucic and other VLCFAs is discussed.
Jadhav
Ashok
A
National Research Council of Canada, Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, Saskatchewan, Canada S7N 0W9.
Katavic
Vesna
V
Marillia
Elizabeth-France
EF
Michael Giblin
E
E
Barton
Dennis L
DL
Kumar
Arvind
A
Sonntag
Cory
C
Babic
Vivijan
V
Keller
Wilfred A
WA
Taylor
David C
DC
D001937:Brassica / Q000235:genetics* / Q000378:metabolism*; D004883:Erucic Acids / Q000378:metabolism*; D044943:Fatty Acid Desaturases / Q000172:deficiency* / Q000235:genetics*; D005227:Fatty Acids / Q000378:metabolism*; D020868:Gene Silencing / Q000502:physiology; D024861:Genetic Enhancement / Q000379:methods*; D015202:Protein Engineering / Q000379:methods*; D016372:RNA, Antisense / Q000235:genetics; D013489:Suppression, Genetic / Q000235:genetics
D004883:Erucic Acids; D005227:Fatty Acids; D016372:RNA, Antisense; C049811:erucic acid; D044943:Fatty Acid Desaturases; C040448:delta-12 fatty acid desaturase