Abstract Detail

Biochemistry, metabolism, carbon flux

Lin, Yingyu [1], Chen, Guanqun [1], Mietkiewska, Elzbieta [2], Singer, Stacy Dawn [3], Dyer, John [4], Smith, Mark [5], McKeon, Thomas [6], Zhou, Xue-Rong [7], Weselake, Randall J. [8].

Functional characterization of Lesquerella fendleri phospholipase A (PLA) in transgenic Arabidopsis thaliana producing C18 hydroxy fatty acid.

Hydroxy fatty acid (HFA)-enriched oils are valuable in many oleo-chemical industries. A major natural source of HFA, however, is castor (Ricinus communis) seed which is poisonous to human beings and animals. Therefore, it is desirable to develop agronomically amenable crops that produce high levels of oils enriched in HFA. Although over-expressing a castor FATTY ACID HYDROXYLASE (RcFAH12) in Arabiodpsis thaliana (Arabidopsis) led to the synthesis of HFAs, a high proportion remained within the membrane phospholipid, phosphatidylcholine (PC). Plant phospholipases (PLA) can catalyze the hydrolysis of phospholipids and release the fatty acyl chains from the sn-1 and/or sn-2 positions. These free fatty acids are subsequently channeled into the acyl-CoA pool, which provides substrates for TAG synthesis. Thus, the release of HFA from PC is a critical step for obtaining HFA enriched seed oils. Lesquerella fendleri can accumulate high amounts of C20-HFA (lesquerolic acid, >60% in seed oil) in its seeds via the efficient release of C18-HFA (ricinoleic acid, <1% in seed oil) from phospholipid. The released C18-HFA is then converted to acyl-CoA and is elongated to C20-HFA (acyl-CoA). To determine whether the heterologous expression of PLA from L. fendleri can enhance the removal of HFA from PC, we over-expressed two PLA genes from L. fendleri (LfpPLA-IIIβ and LfpPLA-IIIδ) in a transgenic line of Arabidopsis with a C18-HFA background. In addition, over-expression lines bearing both the R. communis and Arabidopsis homologues of pPLA-IIIβ and pPLA-IIIδ, respectively, were also generated as controls. The possible role of LfpPLA-IIIβ and/or LfpPLA-IIIδ in removing HFA from phospholipid in Arabidopsis with a C18-HFA background will be discussed.

1 - University of Alberta, Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, AB, T6G 2P5, Canada
2 - University of Alberta, Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, Alberta, T6G 2P5, Canada
3 - University of Alberta, Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, AB, T6G 2P5, Canada
4 - United States Department of Agriculture, Agricultural Research Service, Arid-Land Agricultural Research Center, 21881 North Cardon Lane, Maricopa, Arizona, 85138, USA
5 - National Research Council of Canada, 110 Gymnasium Place, Saskatoon, , Saskatchewan, S7N 0W9 , Canada
6 - United States Department of Agriculture, Agricultural Research Service, Pacific West Area, Western Regional Research Center-CIU, 800 Buchanan Street, Albany, California, 94710 , USA
7 - University of California, Berkeley, Integrative Biology, 1001 Valley Life Sciences Building, # 2465, Berkely, CA, 94720-2465, USA
8 - Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Edmonton, Alberta, T6G 2P5, Canada

Keywords:
none specified

Presentation Type: Oral Paper:Papers for Topics
Session: 27
Location: Hall A/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:00 AM
Number: 27005
Abstract ID:1264
Candidate for Awards:None