The use of nitrogen-based fertilizers is harmful for the environment, expensive for small-share farm holders in many parts of the world, but also important for producing high-yielding crops. The legume family of plants (soy, peas, peanuts) can acquire their own nitrogen from associations with bacteria in the soil. This plant-bacteria relationship is interesting from a biological perspective but also has potential to be applied to other species, like rice and wheat, to reduce to yield-reliability on nitrogen-based fertilizer. Legumes interact with nitrogen-acquiring bacteria by housing them within cells of a specialized organ termed a nodule. The objective of this project is to understand how legumes use a plant growth hormone called Gibberellin to regulate nodule development. I am doing this by using a cutting-edge technology to measure how much Gibberellin is in each cell under the microscope during nodule development. I developed this technology in the model legume called Medicago truncatula. I’ve spatially mapped Gibberellin during nodule development and found surprising but clear patterns of Gibberellin gradients in nodules. I’ve also developed Gibberellin visualization tools in barley, an important crop to many European farmers. Most plants, including barley, can associate with soil fungi within their roots to acquire nutrients, like Phosphorus, from the soil. Despite the differences in microorganisms, these two symbioses are quite similar and share common host genes that enable interaction. I have thus spatially-mapped Gibberellin patterns during fungi interactions in barley roots, finding surprising and clear accumulation patterns. These studies provide an interesting frame work to compare and contrast how Gibberellin is functioning in symbiosis and will help inform Gibberellin-based breeding targets for producing more sustainable crops.
