New Findings about the Relationship between Fungi and Plant Roots

Posted by Ilsa Miller on September 1st, 2021

Almost all crop plants are in contact with a special type of fungus called arbuscular mycorrhizal fungi in the soil, which greatly expands their root surface area. This mutually beneficial interaction promotes the ability of plants to absorb nutrients essential to growth.

The more nutrients that plants naturally obtain, the less artificial fertilizers they need. Understanding this natural process, as the first step to potentially enhance it, is an ongoing research challenge. This progress may bring huge dividends to agricultural productivity.

In a study published in the journal PLOS Biology, researchers used the bright red pigment of beet roots, betaine, to visually track soil fungi as they settle on the roots of living plants.

“We can now track how the relationship between fungi and plant roots develops in real time, from the moment they come into contact. Dr. Sebastian Schornack, a researcher at the Sainsbury Laboratory at the University of Cambridge and co-senior author of the paper, said: \"We didn\'t know what happened before, because without a precise microscope, we couldn\'t see it in living plants.”

To achieve their results, the researchers designed two model plants, a legume and a tobacco plant, so that when arbuscular mycorrhizal fungi are present in their roots, they can produce highly visible beets Alkaline pigments. This involves combining the control regions of two genes activated by mycorrhizal fungi with the gene that synthesizes red betaine pigment.

These plants are then planted in a transparent structure so that the root system can be seen, and images of the root system can be taken with a flatbed scanner without disturbing the plants.

Using their technique, researchers can select the red part of the root system to observe the fungus more closely, as it enters a single plant cell and forms a complex tree-like structure called arbuscular branches that grow on the roots of the plant. Arbuscular plants absorb nutrients from the soil, otherwise the plants would not be able to obtain these nutrients.

There are other ways to visualize this process, but these methods include digging out and killing plants, using chemicals or expensive microscopes. This work makes it possible for the first time to observe with the naked eye and simple imaging how symbiotic fungi begin to colonize living plant roots and parasitize certain parts of the plant root system over time.

“This is an exciting new tool that can visualize this process, as well as other important plant processes. Beetroot pigment is a unique color, so it is easy to see. Researcher in the Department of Plant Science, University of Cambridge, senior of the paper Co-author Dr. Sam Brockington said: \"They have another advantage that they are natural plant pigments, so plants can easily accept them.”

Mycorrhizal fungi have attracted more and more interest in agriculture. This new technology provides the ability to \"track and trace\" the presence of symbiotic fungi in soil from different sources and locations. Researchers say this will allow the fungus to choose the fastest plant to colonize and provide the greatest agricultural benefits.

Understanding and using the dynamics of fungus colonization in plant roots has the potential to increase future crop yields in an environmentally sustainable way. If plants can absorb more nutrients naturally, this will reduce the need for artificial fertilizers, thus saving money and reducing related water pollution.

Collected by Lifeasible, a biotechnology company that is specialized in agricultural science, offering a wide variety of agro-related services and products.