Maize

One Plant. Multiple root types. Many jobs. 
Scroll down to learn more about our work on maize.

Strength vs Supply

Exploring how maize balances structural support with water and nutrient capture, revealing new opportunities to breed crops that are more resilient, productive and climate-ready

Root type nutrient uptake

Uncovering the roles of different maize root types in nutrient capture.​

Understanding Supply and Support Trade-offs in Maize Aerial Roots

Team: Erin Sparks and Amanda Rasmussen
Funded by: Royal Society International Exchange funding 
Years: 2021-2023 (ongoing)
A growing world population, increasing frequencies of extreme weather events, and a need to reduce the carbon footprint of agricultural systems provides a complex challenge for plant biologists. To understand how to solve this complex challenge, we need to understand the trade-offs between optimizing different plant functions. Maize is the most grown crop globally providing food for people and livestock and also serves as an important biofuel. However, maize is susceptible to being blown over, which dramatically reduces yields and makes harvests impossible. My collaborator (E. Sparks) has shown that maize has a unique adaptation in the form of aerial roots (called brace roots) that provide additional support. My lab (A. Rasmussen) is exploring how the different types of maize roots take up nutrients and water and move them around the plant under stressful environments. Together, we queried – is there a trade-off between optimizing roots for stability and their ability to uptake nutrients and water? This exciting cross-disciplinary project will combine Rasmussen’s expertise on resource supply with Sparks’ expertise on mechanical support to determine whether we can identify germplasm that optimizes both strength and resource capture and movement. We will unravel what controls the trade-off between supply and support to understand the boundaries so we can optimise maize varieties for local conditions, providing farmers with the best chance at future-proofing their farm and our food supplies.
Publications: 
Sparks, E.E. and Rasmussen, A. (2023), Trade-offs in plant responses to the environment. Plant Cell Environ, 46: 2943-2945. https://doi.org/10.1111/pce.14689
Kamei T*, Ikiriko II*, Abernathy SM, Rasmussen A and Sparks EE. “Brace Roots” Submitted to WikiJournal of Science, 2023.
Rasmussen A*, Erndwein L, Stager A, Reneau JW and Sparks EE*. “Bigger is better: Thicker maize brace roots are advantageous for both strength and nitrogen uptake” bioRxiv, 2022.

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Functional differences between Maize root types

Functional differences between maize root types - nutrient uptake and responses
According to the Food and Agriculture Organisation (FAO) there are currently almost 800 million people without an adequate food supply. To feed everyone, food production needs to increase by more than 60% by 2050 in the face of increased extreme weather events such as floods. Furthermore we need to achieve this using less fertiliser because up to 70% of applied fertiliser ends up in waterways where it increases toxic algal blooms, polluting the environment. In order to grow food with less fertiliser applications we need to improve how well plants take up and use nutrients. Improving nutrient uptake will not only help reduce fertiliser applications but will also improve yield on nutrient-poor soils in developing countries.
Plant roots are responsible for nutrient uptake and consequently play an important role in the resilience and productivity of crops. Cereal root systems are particularly interesting because unlike a tree with a tap root which branches into side roots, cereal crops depend on roots that grow from the stem. These stem formed roots are similar to roots that form on stem cuttings from garden plants. Past research has treated cereal crop roots like tap or side roots. This is a problem because recent research has shown that stem formed roots are quite different. However what’s unknown is whether these root types have different functions such as in nutrient uptake from the soil. If we are to improve food production using less fertiliser understanding this is crucial. This is the focus of this research project.
Globally, corn is one of the most widely used grain for food production and is also important for fodder and biofuels. Corn is also an ideal species for studying stem root types because it grows several different types including crown (below ground) and brace (above ground) roots. Because of these factors, corn is the plant we are using to measure nutrient uptake and response in different root types

Since very little is known about growth patterns of roots, the timing and stages of maize root development will be recorded in soil containing different nutrient levels. At The University of Nottingham it is possible to see the roots in the soil using a form of x-ray called microCT scanning. This technique allows us to separate the roots from soil and we can image the same plant multiple times meaning we can observe root growth over time.

Using special forms of nutrient which we can track in the plant, we can also measure how well each root type takes up nutrients such as nitrogen, phosphorus or sulphur. This is important because if we want to select the best root system for a particular environment we also need to know how well they can use the available resources. In addition, nutrient uptake in roots occurs through channels which are controlled by particular genes. By measuring these genes we can find out if changes in nutrient uptake are due to changes in the number of channels.

This research will improve our understanding of the functioning of an important class of roots in our most important cereal crops. Understanding how these roots respond to different environments will allow us to breed more effective crops to improve food production more sustainably
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Publications: 
Findimila Dio Ishaya and Amanda Rasmussen; Quantifying nitrogen uptake rates of maize roots using stable isotopes; Cold Spring Harbor Protocol (accepted 2024)
Findimila Dio Ishaya and Amanda Rasmussen; methods for measuring nutrient uptake in maize using nitrogen stable isotopes Cold spring Harbor Protocol (accepted 2024)

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