title: Construction of transplastomic lettuce (Lactuca sativa) dominantly producing astaxanthin fatty acid esters and detailed chemical analysis of generated carotenoids.
abstract: The plastid genome of lettuce (Lactuca sativa L.) cv. Berkeley was site-specifically modified with the addition of three transgenes, which encoded β,β-carotenoid 3,3'-hydroxylase (CrtZ) and β,β-carotenoid 4,4'-ketolase (4,4'-oxygenase; CrtW) from a marine bacterium Brevundimonas sp. strain SD212, and isopentenyl diphosphate isomerase from a marine bacterium Paracoccus sp. strain N81106. Constructed transplastomic lettuce plants were able to grow on soil at a growth rate similar to that of non-transformed lettuce cv. Berkeley and generate flowers and seeds. The germination ratio of the lettuce transformants (T0) (98.8%) was higher than that of non-transformed lettuce (93.1 %). The transplastomic lettuce (T1) leaves produced the astaxanthin fatty acid (myristate or palmitate) diester (49.2% of total carotenoids), astaxanthin monoester (18.2%), and the free forms of astaxanthin (10.0%) and the other ketocarotenoids (17.5%), which indicated that artificial ketocarotenoids corresponded to 94.9% of total carotenoids (230 μg/g fresh weight). Native carotenoids were there lactucaxanthin (3.8%) and lutein (1.3 %) only. This is the first report to structurally identify the astaxanthin esters biosynthesized in transgenic or transplastomic plants producing astaxanthin. The singlet oxygen-quenching activity of the total carotenoids extracted from the transplastomic leaves was similar to that of astaxanthin (mostly esterified) from the green algae Haematococcus pluvialis.
authors.affiliation: Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi-shi, Ishikawa, 921-8836, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Harada
authors.forename: Takashi
authors.initials: T
authors.lastname: Maoka
authors.forename: Ayako
authors.initials: A
authors.lastname: Osawa
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Hattan
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Kanamoto
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Shindo
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Otomatsu
authors.forename: Norihiko
authors.initials: N
authors.lastname: Misawa
mesh_terms: D020561:Alphaproteobacteria / Q000201:enzymology; D015139:Blotting, Southern; D002338:Carotenoids / Q000032:analysis* / Q000096:biosynthesis; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018525:Germination / Q000502:physiology; D018545:Lactuca / Q000235:genetics* / Q000254:growth & development; D006899:Mixed Function Oxygenases / Q000235:genetics*; D009226:Myristates / Q000032:analysis; D010168:Palmitates / Q000032:analysis; D030821:Plants, Genetically Modified / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D026082:Singlet Oxygen / Q000378:metabolism; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D017931:DNA Primers; D009226:Myristates; D010168:Palmitates; D024341:Xanthophylls; D026082:Singlet Oxygen; D002338:Carotenoids; C005948:astaxanthine; D006899:Mixed Function Oxygenases