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Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid onto Triacylglycerol.
Plant Physiol. 2020 10; 184(2):709-719.PP

Abstract

Oilseeds produce abundant triacylglycerol (TAG) during seed maturation to fuel the establishment of photoautotrophism in the subsequent generation. Commonly, TAG contains 18-carbon polyunsaturated fatty acids (FA), but plants also produce oils with unique chemical properties highly desirable for industrial processes. Unfortunately, plants that produce such oils are poorly suited to agronomic exploitation, leading to a desire to reconstitute novel oil biosynthesis in crop plants. Here, we studied the production and incorporation of hydroxy-fatty acids (HFA) onto TAG in Arabidopsis (Arabidopsis thaliana) plants expressing the castor (Ricinus communis) FAH12 hydroxylase. One factor limiting HFA accumulation in these plants is the inefficient removal of HFA from the site of synthesis on phosphatidylcholine (PC). In Arabidopsis, lysophosphatidic acid acyltransferase (LPCAT) cycles FA to and from PC for modification. We reasoned that the castor LPCAT (RcLPCAT) would preferentially remove HFA from PC, resulting in greater incorporation onto TAG. However, expressing RcLPCAT in Arabidopsis expressing FAH12 alone (line CL37) or together with castor acyl:coenzyme A:diacylglycerol acyltransferase2 reduced HFA and total oil yield. Detailed analysis indicated that RcLPCAT reduced the removal of HFA from PC, possibly by competing with the endogenous LPCAT isozymes. Significantly, coexpressing RcLPCAT with castor phospholipid:diacylglycerol acyltransferase increased novel FA and total oil contents by transferring HFA from PC to diacylglycerol. Our results demonstrate that a detailed understanding is required to engineer modified FA production in oilseeds and suggest that phospholipase A2 enzymes rather than LPCAT mediate the highly efficient removal of HFA from PC in castor seeds.

Authors+Show Affiliations

Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 jab@wsu.edu.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

32737074

Citation

Lunn, Daniel, et al. "Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid Onto Triacylglycerol." Plant Physiology, vol. 184, no. 2, 2020, pp. 709-719.
Lunn D, Le A, Wallis JG, et al. Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid onto Triacylglycerol. Plant Physiol. 2020;184(2):709-719.
Lunn, D., Le, A., Wallis, J. G., & Browse, J. (2020). Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid onto Triacylglycerol. Plant Physiology, 184(2), 709-719. https://doi.org/10.1104/pp.20.00691
Lunn D, et al. Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid Onto Triacylglycerol. Plant Physiol. 2020;184(2):709-719. PubMed PMID: 32737074.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Castor LPCAT and PDAT1A Act in Concert to Promote Transacylation of Hydroxy-Fatty Acid onto Triacylglycerol. AU - Lunn,Daniel, AU - Le,Anh, AU - Wallis,James G, AU - Browse,John, Y1 - 2020/07/31/ PY - 2020/05/29/received PY - 2020/07/23/accepted PY - 2020/8/2/pubmed PY - 2021/5/13/medline PY - 2020/8/2/entrez SP - 709 EP - 719 JF - Plant physiology JO - Plant Physiol VL - 184 IS - 2 N2 - Oilseeds produce abundant triacylglycerol (TAG) during seed maturation to fuel the establishment of photoautotrophism in the subsequent generation. Commonly, TAG contains 18-carbon polyunsaturated fatty acids (FA), but plants also produce oils with unique chemical properties highly desirable for industrial processes. Unfortunately, plants that produce such oils are poorly suited to agronomic exploitation, leading to a desire to reconstitute novel oil biosynthesis in crop plants. Here, we studied the production and incorporation of hydroxy-fatty acids (HFA) onto TAG in Arabidopsis (Arabidopsis thaliana) plants expressing the castor (Ricinus communis) FAH12 hydroxylase. One factor limiting HFA accumulation in these plants is the inefficient removal of HFA from the site of synthesis on phosphatidylcholine (PC). In Arabidopsis, lysophosphatidic acid acyltransferase (LPCAT) cycles FA to and from PC for modification. We reasoned that the castor LPCAT (RcLPCAT) would preferentially remove HFA from PC, resulting in greater incorporation onto TAG. However, expressing RcLPCAT in Arabidopsis expressing FAH12 alone (line CL37) or together with castor acyl:coenzyme A:diacylglycerol acyltransferase2 reduced HFA and total oil yield. Detailed analysis indicated that RcLPCAT reduced the removal of HFA from PC, possibly by competing with the endogenous LPCAT isozymes. Significantly, coexpressing RcLPCAT with castor phospholipid:diacylglycerol acyltransferase increased novel FA and total oil contents by transferring HFA from PC to diacylglycerol. Our results demonstrate that a detailed understanding is required to engineer modified FA production in oilseeds and suggest that phospholipase A2 enzymes rather than LPCAT mediate the highly efficient removal of HFA from PC in castor seeds. SN - 1532-2548 UR - https://www.unboundmedicine.com/medline/citation/32737074/Castor_LPCAT_and_PDAT1A_Act_in_Concert_to_Promote_Transacylation_of_Hydroxy_Fatty_Acid_onto_Triacylglycerol_ L2 - https://academic.oup.com/plphys/article-lookup/doi/10.1104/pp.20.00691 DB - PRIME DP - Unbound Medicine ER -