Designing the Superplant: Increasing Lipid Signaling for Enhanced Phosphorus Uptake

Abstract: Phosphate is fundamental for optimal growth and reproduction for plants. However, due to low solubility, not all phosphorus in the soil is available to the plant. It has recently been discovered that plants can take up complex phosphate-containing organic compounds, such as phospholipids. This depends on membrane transporters, more specifically lipid flippases. In the model plant Arabidopsis, the lipid flippases ALA10 is upregulated by phosphate deficiency. ALA10 form together with ALA9, ALA11 and ALA12 an evolutionary subfamily, suggesting that they might be involved in similar cellular functions. The aim was to design a strategy to obtain proof of concept that hyperactivation of specific flippases can lead to plants with an increased phosphate utilization efficiency, using Arabidopsis as a model organism. This was done by creating yeast transformants containing C-terminal deletions of ALA10-ALA12 and a beta subunit. Lipid translocation was tested using flow cytometry. A small plant experiment was conducted to see if plants can grow under a phosphate deficiency. It was found that the lipid uptake assay tested in this study was not enough to tell if ALA10-ALA12 with C-terminal deletions results in more lipid translocation and further investigation is needed. Preliminary results of ALA9 specificity suggest that it is a phosphatidylserine (PS) transporter. Results from a growth experiment suggest that Arabidopsis can grow under phosphate deficiency with a media containing lipids.