Characterization of a PLDζ2 Homology Gene from Developing Castor Bean Endosperm

• Author(s) / Creator(s)

  • Tian, Bo
  • Sun, Meijuan
  • Jayawardana, Kethmi
  • Wu, Ding
  • Chen, Guanqun

• Castor oil contains approximately 90% ricinoleic acid (RA) which is stored mainly in the form of tri‐ricinoleic acid containing triacylglycerols (TAG). Ricinoleate is synthesized from oleate (18:1n‐9) esterified to the sn‐2 position of phosphatidylcholine (PtdCho) catalyzed by oleoyl‐12‐hydroxylase. PtdCho‐derived diacylglycerol (DAG) is an important substrate pool for TAG synthesis, and the interconversion between PtdCho and DAG has been shown to play a critical role in channeling hydroxy fatty acids (HFA) to TAG. Although phospholipase D (PLD) has been reported to catalyze the hydrolysis of PtdCho to produce phosphatidic acid which can then be converted to DAG, its potential functions in the channeling of RA from PtdCho to DAG and the assembly of RA on TAG is largely unknown. In the present study, 11 PLD genes were identified from the Castor Bean Genome Database. Gene expression analysis indicated that RcPLD9 is expressed at relatively high levels in developing seeds compared to other plant tissues. Sequence and phylogenetic analyses revealed that RcPLD9 is a homolog of Arabidopsis PLDζ2. Overexpression of RcPLD9 in the Arabidopsis CL7 line producing C18‐HFA resulted in RA content reductions in the polar lipid fraction (mainly PtdCho) and mono‐HFA‐TAG, but increased RA content in di‐HFA‐TAG. Since part of RA in di‐HFA‐TAG is derived from HFA‐DAG, the results indicated that RcPLD9 facilitates the channeling of RA from PtdCho to DAG for its assembly on TAG in developing seeds.

• Date created

  2020-03-01

• Subjects / Keywords

  • Castor bean
  • Phosphatidylcholine
  • Phospholipase D
  • Ricinoleic acid
  • Triacylglycerol

• Type of Item

  Article (Draft / Submitted)

• DOI

  https://doi.org/10.7939/r3-7xhk-qy10

• License

  This is the peer reviewed version of the following article: Tian, B., Sun, M., Jayawardana, K., Wu, D., & Chen, G. (2020). Characterization of a PLDζ2 Homology Gene from Developing Castor Bean Endosperm. Lipids. , which has been published in final form athttps://doi.org/10.1002/lipd.12231. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.