title: Endoplasmic reticulum-located PDAT1-2 from castor bean enhances hydroxy fatty acid accumulation in transgenic plants.
abstract: Ricinoleic acid (12-hydroxy-octadeca-9-enoic acid) is a major unusual fatty acid in castor oil. This hydroxy fatty acid is useful in industrial materials. This unusual fatty acid accumulates in triacylglycerol (TAG) in the seeds of the castor bean (Ricinus communis L.), even though it is synthesized in phospholipids, which indicates that the castor plant has an editing enzyme, which functions as a phospholipid:diacylglycerol acyltransferase (PDAT) that is specific to ricinoleic acid. Transgenic plants containing fatty acid Δ12-hydroxylase encoded by the castor bean FAH12 gene produce a limited amount of hydroxy fatty acid, a maximum of around 17% of TAGs present in Arabidopsis seeds, and this unusual fatty acid remains in phospholipids of cell membranes in seeds. Identification of ricinoleate-specific PDAT from castor bean and manipulation of the phospholipid editing system in transgenic plants will enhance accumulation of the hydroxy fatty acid in transgenic seeds. The castor plant has three PDAT genes; PDAT1-1 and PDAT2 are homologs of PDAT, which are commonly found in plants; however, PDAT1-2 is newly grouped as a castor bean-specific gene. PDAT1-2 is expressed in developing seeds and localized in the endoplasmic reticulum, similar to FAH12, indicating its involvement in conversion of ricinoleic acid into TAG. PDAT1-2 significantly enhances accumulation of total hydroxy fatty acid up to 25%, with a significant increase in castor-like oil, 2-OH TAG, in seeds of transgenic Arabidopsis, which is an identification of the key gene for oilseed engineering in production of unusual fatty acids.
authors.affiliation: Department of Agricultural Bio-resources, National Academy of Agricultural Science, Rural Development Administration, Suwon, Republic of Korea. hukim64@korea.kr
authors.forename: Hyun Uk
authors.initials: HU
authors.lastname: Kim
authors.forename: Kyeong-Ryeol
authors.initials: KR
authors.lastname: Lee
authors.forename: Young Sam
authors.initials: YS
authors.lastname: Go
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Jung
authors.forename: Mi-Chung
authors.initials: MC
authors.lastname: Suh
authors.forename: Jong Bum
authors.initials: JB
authors.lastname: Kim
mesh_terms: D000217:Acyltransferases / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000235:genetics; D017343:Genes, Plant; D008565:Membrane Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D012277:Ricinoleic Acids / Q000378:metabolism*; D012278:Ricinus / Q000201:enzymology* / Q000235:genetics; D012639:Seeds / Q000201:enzymology* / Q000235:genetics; D014280:Triglycerides / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010743:Phospholipids; D010940:Plant Proteins; D012277:Ricinoleic Acids; D014280:Triglycerides; D000217:Acyltransferases; C426836:phospholipid diacylglycerol acyltransferase; C030521:ricinoleic acid