Phosphorus fertilisers have contributed to major increases in global food production.
But the world is gradually running out of mineable phosphorus reserves. Our research team explores whether plants that have evolved on the world’s most phosphorus soils in south-western Australia can show us how to develop crops that are less reliant on non-renewable phosphorus fertilisers. The plants we study are super-efficient at acquiring phosphorus from soil and also at using that phosphorus for their growth.
The overarching philosophy of our research is that balancing the phosphorus demand for increased global food production with decreasing phosphorus resources can be mitigated by understanding the mechanisms in plants from phosphorus-impoverished soils and exploiting this for future crop plants.
Decreasing reserves of phosphorus fertiliser, a non-renewable resource, are threatening future global food security. The phosphorus-impoverished soils in Australia allowed the evolution of plants that are amazingly efficient at acquiring soil phosphorus, by using specialised roots that effectively ‘mine’ phosphorus plants without such specialised roots cannot access. Following uptake, they also use that phosphorus very efficiently, by replacing most of the phospholipids in their membranes by lipids that do not contain phosphorus. Inside the leaves, they also send the phosphorus to those cells that need it most, rather than to cells that just store it. Most importantly, they operate at very low levels of ribosomal RNA, which contains about 30% of a leaf’s total phosphorus content in most other plants. With such low levels of ribosomal RNA, these leaves produces very little protein and enzymes associated with photosynthesis, yet they photosynthesise at high rates. By focusing on the mechanisms underlying the capacity to acquire and use phosphorus, our research explores whether a plant’s high phosphorus efficiency is traded off against its acclimation potential, as both are essential for future crops.