Fungi could be ‘bio-fertiliser’

A common soil fungus can trigger the growth of plant roots enabling plants to absorb more nutrients creating a bio-fertiliser, according to new research by Uta Paszkowski, of the University of Cambridge’s Department of Plant Sciences.

The research also found that mycorrhizal fungus can enmesh itself in the crop roots at a cellular level pumping nutrients straight to the heart of the plant cells.

Plants ‘colonised’ by the fungi get between 70 to 100% of their phosphate directly from these fungus tendrils, an enormous mineral boost.

The hope is that mycorrhizal fungi could one day act as a ‘bio-fertiliser’ that ultimately replaces the need to mine phosphate from the ground for industrial fertiliser. Finding a replacement for mined phosphate is a critical problem, supply is expected to run out in 30-50 years and run-off  pollutes water sources and causes algal growth.

Dr Uta Paszkowski says: “The big question we are trying to answer is whether and how we can make use of the biofertiliser capacity of mycorrhizal symbiosis in modern and more high input agricultural settings to  allow more intensive farming methods.

“Cereals such as rice, wheat and maize feed billions of people every day and mycorrhizal fungi have a mutualistic relationship with cereals, going back to the earliest days of plant life. By analysing this ancient and common relationship we are gaining insights that could be used to breed crops with the best possible root architectural and symbiotic properties.” she said.

“Plant roots that have the capacity to explore the widest soil area absorb the most nutrients as a consequence and so are likely to have a greater crop yield. By finding out which parts of the genome are responsible for the best plant root systems we can start breeding for the best root ‘architecture’,” said Paszkowski.

Rice is best grown in highly irrigated paddy fields, but there are many parts of the world where this isn’t an option, and 40% of the world’s area for rice crop is grown ‘dry’. However, the plant-fungi relationship that creates enhanced crops actually works best in dry environments. Mycorrhizal fungi could be of huge benefit to those who rely on dry rice crops in some of the poorest areas of Asia and sub-Saharan Africa.

The main hurdle for researchers to overcome is the self-regulation of plants.

“Plants monitor their own nutritional state. If a plant has enough phosphate it will not allow fungus to enter root. We are working on ways to circumvent this so we can allow symbiosis to contribute in better developed countries ” said Paszkowski.

Mycorrhizal fungi are extremely common in all soils around the world, and are an ingredient in many ‘bio’ plant foods found in domestic garden centres, but have yet to be used for industrial agriculture.

See more at: http://www.cam.ac.uk/research