title: Transient silencing of the KASII genes is feasible in Nicotiana benthamiana for metabolic engineering of wax ester composition.
abstract: The beta-ketoacyl-ACP synthase II (KASII) is an enzyme in fatty acid biosynthesis, catalyzing the elongation of 16:0-acyl carrier protein (ACP) to 18:0-ACP in plastids. Mutations in KASII genes in higher plants can lead to lethality, which makes it difficult to utilize the gene for lipid metabolic engineering. We demonstrated previously that transient expression of plastid-directed fatty acyl reductases and wax ester synthases could result in different compositions of wax esters. We hypothesized that changing the ratio between C16 (palmitoyl-compounds) and C18 (stearoyl-compounds) in the plastidic acyl-ACP pool by inhibition of KASII expression would change the yield and composition of wax esters via substrate preference of the introduced enzymes. Here, we report that transient inhibition of KASII expression by three different RNAi constructs in leaves of N. benthamiana results in almost complete inhibition of KASII expression. The transient RNAi approach led to a shift of carbon flux from a pool of C18 fatty acids to C16, which significantly increased wax ester production in AtFAR6-containing combinations. The results demonstrate that transient inhibition of KASII in vegetative tissues of higher plants enables metabolic studies towards industrial production of lipids such as wax esters with specific quality and composition.
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Selcuk
authors.initials: S
authors.lastname: Aslan
authors.affiliation: Department of Plant Breeding, Swedish University of Agricultural Sciences (SLU), Alnarp, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Hofvander
authors.affiliation: Department of Food Science, Uppsala BioCenter, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Paresh
authors.initials: P
authors.lastname: Dutta
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Folke
authors.initials: F
authors.lastname: Sitbon
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden.
authors.forename: Chuanxin
authors.initials: C
authors.lastname: Sun
mesh_terms: D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004952:Esters; D005227:Fatty Acids / Q000378:metabolism; D015870:Gene Expression; D020868:Gene Silencing; D060847:Metabolic Engineering; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D034622:RNA Interference; D016415:Sequence Alignment; D013214:Starch Synthase / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004952:Esters; D005227:Fatty Acids; D010940:Plant Proteins; D014280:Triglycerides; C060756:waxy protein, plant; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D013214:Starch Synthase