Antisense expression of 3-oxoacyl-ACP reductase affects whole plant productivity and causes collateral changes in activity of fatty acid synthase components.
Brassica napus cv Westar plants were transformed with 3-oxoacyl-ACP reductase (KR) in antisense orientation, driven by either the cauliflower mosaic virus 35S promoter or a seed-specific acyl carrier protein promoter to determine the effects on plant productivity and on the activity of other fatty acid synthase (FAS) components. In plants with altered KR activity, total seed yield was reduced in all cases. In less severely affected plant lines, seeds had a normal appearance and composition but the yield of seeds was reduced by approximately 50%. In more severely affected lines, reductions in both seed fatty acid content and the number of seeds produced per plant were evident, resulting in a 90% reduction in fatty acid synthesized per plant. These phenotypes were independent of the promoter used. In severely affected lines, a large proportion of seeds showed precocious germination, and these had a reduced oleate content and increased levels of polyunsaturated 18-carbon fatty acids, compared with normal seeds of the same line. This reduction in 18:1 fatty acids was mimicked on imbibition of seeds with a normal appearance, indicating a preferential use of oleate moieties in precocious germination events. The reduction in activity of KR was mirrored for a second fatty acid synthase component, enoyl-ACP reductase, indicating a mechanism to maintain the ratio of fatty acid synthase components throughout embryogenesis.
O'Hara
Paul
P
School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
Slabas
Antoni R
AR
Fawcett
Tony
T
D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase; D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D018533:Biomass; D029688:Brassica napus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D016373:DNA, Antisense / Q000235:genetics*; D064429:Fatty Acid Synthases / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D016373:DNA, Antisense; D005227:Fatty Acids; D010940:Plant Proteins; D000429:Alcohol Oxidoreductases; D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase; D064429:Fatty Acid Synthases