Fungi can lead to new ‘climate-smart’ crops

Washington: A new study on the relationship between plants and fungi has found that the latter can lead to new 'climate-smart' varieties of crops that are less reliant on fertilisers. These organisms, when added to wheat, were known to boost the uptake of key nutrients and could lead to new 'climate-smart' varieties of crops, according to a new study published in the journal 'Global Change Biology'.

Researchers demonstrated a partnership between wheat and soil fungi that could be utilised to develop new food crops and farming systems which are less reliant on fertilisers, reducing their contribution to the escalating climate crisis. Fungi continued to provide nutrients under higher levels of carbon dioxide (CO2) predicted for 2100, which has important implications for future food security.

"Fungi could be a valuable new tool to help ensure future food security in the face of the climate and ecological crises," said lead researcher Professor Katie Field, from the University of Leeds' School of Biology and Global Food and Environment Institute.

"These fungi are not a silver bullet for improving the productivity of food crops, but they have the potential to help reduce our current overreliance on agricultural fertilisers," Field added. Most plants form partnerships with fungi in their root systems, known as arbuscular mycorrhizas, which enable them to draw nutrients from the soil more efficiently.

In exchange, the plants provide carbohydrates to the fungi as a form of payment, known as a symbiosis. Plants can give 10-20 per cent of the carbon they draw from the air to their fungal partners, in exchange for up to 80 per cent of their required phosphorous intake. These fungi can also help plants increase their growth, nitrogen levels, water uptake, and defend the plant against pests and disease.

But over the last 10,000 years, crop plants have been domesticated through intensive breeding, which has inadvertently stopped some varieties from having such close relationships with beneficial fungi. Whilst some varieties of the wheat grown by farmers form these partnerships with beneficial fungi, many do not.

"For thousands of years, farmers have been breeding crops to increase productivity and disease resistance, but this has mainly been based on what can be seen above ground," said co-author Dr. Tom Thirkell, University of Leeds' School of Biology.

"Our results suggest there is real potential to breed new crop varieties which regain this lost relationship with beneficial fungi and improve the sustainability of future food production systems," he added.

Scientists allowed the fungi to colonize the roots of three different varieties of wheat in the laboratory and grew them in one of two chambers – either mimicking current climatic conditions or those projected for 2100, when CO2 concentration in the atmosphere is predicted to be double that of today if emissions are not curbed.

They wanted to know what benefits the different varieties could gain from their fungal partners and how the relationships would be affected by increasing atmospheric CO2. Some varieties gained much more from the relationship than others for a similar carbohydrate 'cost'.

There was no difference in phosphorus or nitrogen exchange from the fungi to the wheat at the higher CO2 level for any of the three crop varieties. It, therefore, appears that the fungi can continue to transfer nutrients to the crop even under future climate conditions.