New research highlights interactions of bacteria, fungi and roots for plant nutrition

Scientists of the James Hutton Institute, working alongside partners at China Agriculture University, have discovered novel ways in which arbuscular mycorrhizal fungi, bacteria and plant roots interact to influence the transfer of nutrients to plants. Their findings could be harnessed to enhance the sustainability of agricultural crops.

Arbuscular mycorrhizae are a type of fungi that associates with plant roots and helps plants seize nutrients from soil, including phosphorus, sulphur, and nitrogen, through extensive networks of long, branching filaments called ‘hyphae’, but through evolution have lost the ability to utilise phosphorus bound in organic forms.

The new study shows how these hyphae can transport phosphate-solubilising bacteria to patches of organic phosphorus, enhancing the mineralisation of this accumulated P and making it available to plants. The real groundbreaking part of this work was the observation that bacteria swim in the thick water film formed around hyphae to get to the patch of resource. Moreover, the fungi promote this by feeding them along the way with hyphal exudates of easily utilised carbon.

Dr Tim George, a rhizosphere ecologist at the Institute and a co-author of the study, said: “This paper is the product of years of collaboration with the group of Prof Gu Feng at the China Agriculture University in Beijing, which has led to significant breakthroughs.

“We hope our results influence future management of plant-microbe interactions and improve the ability of scientists to use arbuscular mycorrhizal fungi and bacteria to improve the nutrition of crops in soils with limited phosphorus levels.”

Professor Rob Brooker, Head of Ecological Sciences at the Institute, added: “This study is an excellent example of how Hutton scientists are working with partners around the world to examine the interactions between plants, soils and soil biota to provide the resources for crop production and resilience against land use and climate change.”

The paper is in the latest issue of New Phytologist. It also is the focus of a commentary by two world-leading specialists, Jan Jansa and Angela Hodge, published in the same issue of the journal.

Paper: Jiang, F., Zhang, L., Zhou, J., George, T.S. and Feng, G. (2021), Arbuscular mycorrhizal fungi enhance mineralisation of organic phosphorus by carrying bacteria along their extraradical hyphae. New Phytol, 230: 304-315. https://doi.org/10.1111/nph.17081