Plant-microbe symbioses: hormones and the art of self-control

Foo E

School of Natural Sciences, University of Tasmania Hobart, Tasmania, Australia.

To optimise plant growth to meet the demands of a rapidly changing world, we must understand how plants maximise nutrient uptake. In modern agriculture, application of artificial fertilisers is widely used to promote plant growth, with unintended negative consequences for the environment. Another strategy that plants have to gain access to nutrients is the formation of specialised partnerships (symbioses) with soil microbes. In these intimate associations, the microbes enter the plant root and provide previously inaccessible nutrients (nitrogen and phosphorous) in exchange for plant carbon. Leguminous plants such as peas, beans and lentils can host both bacterial and fungal symbionts in the root simultaneously, meaning a particularly delicate balance must be struck to ensure that the nutrient requirements of the plant are met most efficiently. Plant hormones are a discreet set of small molecules with potent effects on plant development. In our work, we examine the role of plant hormones in symbioses using our extensive collection of hormone-related pea mutants and through the measurement of minute quantities of these hormones. This includes a particular focus on how hormones, working alone and together, influence the development of the root to successfully accommodate the microbial partners.