caa a22 4500 47710049X CHVBK 20180405111539.0 cr unu---uuuuu 170330e19960101xx s 000 0 eng 10.1007/BF00197585 doi (NATIONALLICENCE)springer-10.1007/BF00197585 Medium-chain fatty acid biosynthesis and utilization in Brassica napus plants expressing lauroyl-acyl carrier protein thioesterase [Elektronische Daten] [Victoria Eccleston, Ann Cranmer, Toni Voelker, John Ohlrogge] We have examined production of mediumchain fatty acids by Brassica napus L. plants transformed with a California bay (Umbellularia californica) medium-chain acyl-acyl carrier protein (ACP) thioesterase (UcFatB1) cDNA under the control of the constitutive cauliflower mosaic virus 35S promoter. These plants were found to accumulate medium-chain fatty acids in seeds but not in leaves or roots. Assay of thioesterase activity in extracts of leaves indicated that lauroyl-ACP thioesterase activity is comparable to oleoyl-ACP thioesterase (EC 3.1.2.14) activity in transformant leaves. Furthermore, leaf lauroyl-ACP thioesterase activity was in excess of that which produced a significant increase in the amount of laurate (12:0) in seed. Studies in which isolated chloroplasts were 14C-labelled were used to evaluate whether medium-chain fatty acids were produced in transformed leaves. Up to 34% of the fatty acids synthesized in vitro by isolated chloroplasts were 12:0. These results demonstrate that the normally seed-localized lauroyl-ACP thioesterase can be expressed in active form in leaves, imported into chloroplasts and can access acyl-ACP intermediates of leaf de-novo fatty acid synthesis. The most likely explanation for the lack of accumulation of 12:0 in transformed leaves is its rapid degradation by β-oxidation. In support of this hypothesis, isocitrate lyase (EC 4.1.3.1) activity was found to be significantly increased in plants transformed with 35S-UcFatB1. Springer-Verlag, 1996 β-Oxidation nationallicence Brassica nationallicence Fatty acid synthesis nationallicence Leaf nationallicence Medium-chain acyl-ACP thioesterase nationallicence Umbellularia nationallicence ACP : acyl carrier protein nationallicence CaMV : cauliflower mosaic virus nationallicence control : Brassica napus cultivar 212/86 nationallicence event 8 : pCGN3831-212/86-8 nationallicence event 11 : pCGN3831-212/86-11 nationallicence FAS : fatty acid synthase nationallicence IL : isocitrate lyase nationallicence KAS : β-keto-acyl ACP synthase nationallicence MS : malate synthase nationallicence OTE : oleoyl-ACP thioesterase nationallicence TAG : triacylglycerol nationallicence UcFatB1 : California bay medium-chain acyl-ACP thioesterase nationallicence Eccleston Victoria Department of Botany and Plant Pathology, Michigan State University, 48824-1312, East Lansing, MI, USA aut Cranmer Ann Calgene Inc., 1920 Fifth Street, 95616, Davis, CA, USA aut Voelker Toni Calgene Inc., 1920 Fifth Street, 95616, Davis, CA, USA aut Ohlrogge John Department of Botany and Plant Pathology, Michigan State University, 48824-1312, East Lansing, MI, USA aut Planta Springer-Verlag 198/1(1996-01-01), 46-53 0032-0935 198:1<46 1996 198 425 https://doi.org/10.1007/BF00197585 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00197585 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Eccleston Victoria Department of Botany and Plant Pathology, Michigan State University, 48824-1312, East Lansing, MI, USA aut NATIONALLICENCE 700 1- Cranmer Ann Calgene Inc., 1920 Fifth Street, 95616, Davis, CA, USA aut NATIONALLICENCE 700 1- Voelker Toni Calgene Inc., 1920 Fifth Street, 95616, Davis, CA, USA aut NATIONALLICENCE 700 1- Ohlrogge John Department of Botany and Plant Pathology, Michigan State University, 48824-1312, East Lansing, MI, USA aut NATIONALLICENCE 773 0- Planta Springer-Verlag 198/1(1996-01-01), 46-53 0032-0935 198:1<46 1996 198 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer