Harnessing mechanisms for plant carbon delivery to symbiotic soil fungi for sustainable food production

Introduction

The arbuscular mycorrhizal (AM) symbiosis between plants and symbiotic soil fungi confers key nutritional benefits to plants. AM fungi increase plant productivity by up to 30% by improving mineral nutrient uptake from the soil. In exchange for these nutrients, plants transfer more than one gigaton of photosynthetically fixed carbon each year to the AM fungal network in the soil. This carbon transfer has a major impact not just on plant and fungal physiology, but also on the global carbon cycle.

Previous Work

My previous work identified a molecular pathway in plant roots that is activated during fungal colonization of root cells and transfers fixed carbon to AM fungi in the form of lipids. This finding represents a breakthrough in the field of AM symbiosis as we were able to describe, for the first time, how and in which form carbon is delivered to AM fungi.

Proposed Research

My discovery unlocks an opportunity: I propose to engineer the model crop rice to maximize carbon delivery to the fungal mycelium by exploiting the mechanisms underpinning carbon allocation to AM fungi. This approach could lead to enhanced nutrient uptake by promoting the symbiotic association, thereby reducing the need for synthetic fertilizer. Moreover, it also has the potential to increase carbon sequestration and soil fertility.

Research Gaps

However, it is currently unknown how plant carbon metabolism is altered at a whole plant level to increase carbon flux to the fungal mycelium, and how plants control the amount of carbon allocated to AM fungi.

Methodology

To achieve this ambitious aim, I will exploit the recent technological advances in:

1. Genetics
2. Carbon tracing
3. Single cell transcriptomics

These will be used to:

• Map the carbon allocation pathway from leaves to roots and to AM fungi at single cell resolution (aim 1).
• Identify the genetic and transcriptional regulators of this pathway (aim 2).
• Maximize carbon delivery from crop plants to the fungal mycelium in the soil (aim 3).