HYDROTROPISM: Abscisic acid and the mechanisms that regulate hydrotropism

Despite ABA being the most important phytohormone in the response of plants to drought stress little is known about how water deficits are perceived by plants. Although ABA has been traditionally described as a growth inhibitor, different reports have shown a role for ABA promoting growth. Under water stress ABA inhibits shoot growth and maintains root growth in order to guarantee water uptake. In fact, roots grow towards zones with higher water contents and this response is called hydrotropism. This project is focused on the study of the mechanisms that link the perception of water deficits in the soil with the adaptive responses caused by ABA that are directed to ensure plant survival. The identification of the mechanism by which an environmental signal causes a modification of root growth will be investigated. The discovery of the elements responsible for transmitting the water deficit signal and the proteins involved in this signaling pathway will compose the first part of the project. Next, the creation of multiscale models capturing the response integrating dynamic changes in ABA response, biomechanics and root growth in response to hydrotropic stimuli as well as the use of non invasive micro CT imaging of root systems will help to understand how plants respond to osmotic gradients in soil. The study of the mechanisms that regulate root growth and bending will help create useful tools directed to reduce crop losses caused by this stress. The aim is to create an integrative point of view of the role of this hormone in the context of growth regulation using the modeling, genetic and imaging techniques as well as the long experience of Prof. Malcolm Bennett in the study of gravitropism and auxin regulated plant growth.