Scientists target international agriculture’s phosphate shortage

By 2030, the world’s population is projected to be about 8.5 billion people. Global food security is a major concern for governments — zero hunger is the second most important of the United Nations Sustainable Development Goals.

However, there is a severe conflict between sustainable food production and the use of nonrenewable resources in agricultural systems, particularly phosphate. Phosphorus is a major mineral nutrient required by crop plants for optimal growth and productivity. Phosphate is the only form of phosphorus that plants can absorb — it is often applied to crops as phosphate fertilizer.

Seventy percent of the world’s phosphate reserves are located in North Africa. China, Russia, South Africa and the United States all have limited quantities of the mineral rock.

Scientists have reported that global phosphate production will peak around 2030, at the same time the global population will reach 8.5 billion people. Several reports have also warned that the global reserve would be depleted within the next 50 to 100 years.

A phosphate shortage could threaten global food production.

As well, plants can uptake only small amounts of phosphate, so much of it ends up in unwanted places, like bodies of water, making many agricultural practices ecologically and financially unsustainable.

And as phosphate becomes more expensive and more rare, it poses a food security threat, but could also spark political crises between phosphate-rich countries and importing countries.

My doctoral research at the Global Institute for Food Security at the University of Saskatchewan investigates the role of mobile molecules in the integration of root and shoot growth under mineral deficiency conditions.

Currently, researchers across multiple disciplines are looking for ways to optimize phosphate use in crop plants. Soil scientists seek ways to improve soil phosphate management, while plant biologists have intensified their efforts in understanding how plants can adapt to limited phosphorus.

It is already understood that when plants are starved of phosphate, they stop the growth of their primary root and grow more secondary roots and root hairs to increase their ability to absorb phosphate in soil with lower levels of the mineral. This strategy is referred to as changes in root-system architecture.

Another strategy is that during low-phosphate conditions, plants are able to remobilize stored phosphate to other parts of the plant to maintain growth and development. During this period, plants increase the expression of genes involved in phosphate uptake from the soil. In other words, more effort is committed to looking for and acquiring phosphate.

Advancements in genomics and biochemistry have helped us to uncover some of the genes and proteins that control these processes. However, some regulatory genes that control plant response to low phosphate are still unknown, making it difficult to breed crops that are well adapted to low amounts of phosphate.

This month, as reported in the journal Plant Physiology, an international team of scientists discovered a protein in plants that senses phosphorus levels in the soil and then tells the plant to adjust growth and flowering. The protein, called SPX4, tells the plant when it has acquired enough phosphorus and co-ordinates with the roots to stop uptake.

This discovery will help us to understand how plants can perform well even with limited phosphorus application.

Another research project published in the journal Cell identified a gene that regulates root-system architecture. Researchers showed that this gene modulates a plant hormone, ultimately regulating the depth of the root system.

The study of phosphate signaling in plants will ultimately help us to produce enough food for the growing population without having an adverse effect on the environment.

Government and funding agencies should support more fundamental and applied research that seek to understand how plants behave under low phosphate conditions.

Toluwase Olukayode is a PhD student studying at the Global Institute for Food Security at the University of Saskatchewan. This column first appeared on theconversation.com. It has been edited for length.

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