Login


Plants force fungal partners to behave fairly

Plants react intelligently to their environment: If they can choose between more cooperative and less cooperative fungal partners, they supply the latter with fewer nutrients and thus force them to cooperate more. Based on these findings, scientists believe that plants could also be used to test market and behavioral theories.

Do plants operate according to economic criteria? They do, when they are mutualized with fungal partners that demonstrate differing degrees of cooperation. “Carbs for phosphates”, that’s the deal between plants and mycorrhizal fungi, which can only feed themselves together with a partner: The plant supplies the fungus with carbohydrates and is ‘paid back’ in phosphates. Additional phosphates are extremely attractive for the plant, as they allow it to grow better.

Good partners force worse partners to improve their performance
It really gets interesting when plants are mutualized with fungal partners of varying degrees of cooperativeness: a ‘meaner’ one, which supplies fewer phosphates per unit of carbohydrate provided, and a ‘more generous’ one, which ‘pays’ more phosphates for its nutrients. “In a case like this, the plant can deliberately decide to provide the meaner partner with fewer carbohydrates.” That’s how ecologists Pascal Niklaus and Bernhard Schmid from the University of Zurich (Switzerland) sum up the results of their new study.

As if that were not enough, the plant can practically ‘starve’ the less cooperative fungal partner by supplying it with fewer nutrients, thus forcing it to supply more of the sought-after phosphates. In this way the partner is encouraged to give back around the same amount as the more generous fungus. Andres Wiemken from the University of Basel explains this phenomenon as follows: “The plant exploits the competitive situation of the two fungi in a targeted manner, triggering what is essentially a market-based process determined by cost and performance”.

Based on this completely new insight into the behavior and decision-making ability of plants, the researchers believe that plants would be suitable for testing general market-based theories. “Because plants make their decisions based on physiological processes and are not distracted from the best course of action by subjective thought, they could even be better models than animals and people”, says Bernhard Schmid from the University of Zurich.

Better productivity thanks to mycorrhizal fungi
The basic research, funded by Syngenta within the framework of the “Plant Decision Making” Project at the Zurich-Basel Plant Science Center also provides practical findings for the agriculture sector. “Mycorrhizal fungi increase the sustainability and productivity of agricultural eco-systems”, explains Bernhard Schmid. For this reason, it is essential to maintain as much diversity within mycorrhizal fungi as possible in the agriculture sector going forward.

Age-old mutualism of plants and mycorrhizal fungi
Mycorrhizal fungi can survive only in the presence of a plant partner, as they are not able to feed themselves. The fungus uses its hyphae to penetrate the plant’s root system, where the plant supplies it with carbohydrates. The plant also benefits from this arrangement, as the fungus provides the plant with phosphates and other nutrients – with varying degrees of generosity. These natural fertilizers are decisive for plant growth, so mutualism with the mychorrhizal fungus is beneficial even if the fungus does not always cooperate fully.

Plant and mychorrhizal fungus mutualism has existed globally for more than 400 million years. Plant-fungus systems like these will play a significant role in more sustainable agriculture in the future.

Read the paper in Ecology Letters: Options of partners improve carbon for phosphorus trade in the arbuscular mycorrhizal mutualism.

Article source: University of Zurich

Image credit: UZH

News

Harvests in the US to suffer from climate change

Some of the most important crops risk substantial damage from rising temperatures. To better assess how climate change caused by human greenhouse gas emissions will likely impact wheat, maize and soybean, an international team of scientists now ran an unprecedentedly comprehensive set of computer simulations of US crop yields. The simulations were shown to reproduce the observed strong reduction in past crop yields induced by high temperatures, thereby confirming that they capture one main mechanism for future projections. Importantly, the scientists find that increased irrigation can help to reduce the negative effects of global warming on crops - but this is possible only in regions where sufficient water is available. Eventually limiting global warming is needed to keep crop losses in check.


New research addresses gap between research and practice in sustainable agriculture

Michigan State University-led research has found a big difference in the yields produced by alternative agricultural practices in commercial fields compared with the same practices in the small experimental plots ordinarily used to test them.


Scientists develop new wheat-wheatgrass hybrid

With a hybrid crop called Salish Blue, scientists at Washington State University have combined wheat and wheatgrass in a new species with the potential to help Pacific Northwest farmers and the environment.