Enzymes in chloroplasts and endoplasmic reticulum work in cooperation in the synthesis of plant lipids

February 1, 2023

Application to biodiesel production technology is expected

RIKEN CSRS has revealed that plant enzymes LPPα2 and LPPε1 collaboratively play an important role in the synthesis of lipids and growth of plants.

The endoplasmic reticulum (ER) is a major site of lipid biosynthesis in a cell, and phosphatidic acid phosphatases (PAPs) have been thought to catalyze a key reaction step in lipid synthesis. However, the identities of these enzymes in plants have long been unknown.

In this study, the research team found that double knockout mutants of LPPα2 and LPPε1 lead to a lethal phenotype in the model plant Arabidopsis thaliana, and thus hypothesized that these two enzymes, among many candidate PAP enzymes present, are collaboratively responsible for the synthesis of lipids. They found that LPPε1 is localized in chloroplasts while LPPα2 is localized in the ER. When LPPα2 and LPPε1 were overexpressed in plants, the amount of lipids in seeds increased by about 20% in both cases. In addition, LPPε1 was found to be localized at a specific site of chloroplast outer envelopes, being close to LPPα2 in ER. From these results, they proposed a new mechanism of lipid biosynthesis in which enzymes at different locations in a cell collaborate at a specific site, possibly at a contact site, where chloroplasts and ER are in close proximity.

The results of this research are expected to contribute to the development of technology for synthesizing useful compounds, such as biodiesel, in plants using metabolic engineering technology.

Original article
The Plant Cell doi:10.1093/plcell/koad021
V. C. Nguyen, Y. Nakamura,
"Distinctly localized lipid phosphate phosphatases mediate endoplasmic reticulum glycerolipid metabolism in Arabidopsis".
Yuki Nakamura
Team Leader
Plant Lipid Research Team