Abstract - Plants that exhibit moisture-regulated root branching, called hydropatterning, are able to detect spatial differences in water distribution around their root growth zone, which leads to pre-patterning of lateral root primordia towards regions of higher water availability. This response may explain some of the environmental plasticity that has been observed in root system architecture. Understanding the origin and control of this plasticity is pivotal in our pursuit to tune root branching and development for more efficient nutrient and water uptake in a changing environment. Moreover, dissecting the genetic control of hydropatterning may be a unique opportunity to understand water sensing mechanisms in plants as a whole. Recently, we characterized the hydropatterning responses of a diverse population of 250 maize inbred lines using a novel high-throughput phenotyping platform. We observed that the roots of most inbred lines show a strong hydropatterning response. The highest variance in hydropatterning was observed in inbred lines of the non-stiff stalk subpopulation. Interestingly, this variance showed good correlations to in-field root architecture. We used SNP-based GWAS and TWAS (transcriptome-wide association studies) to identify hydropatterning-associated genes. Some of these genes had previously been identified as being differentially regulated across the root growth zone during hydropatterning or had been reported in other studies in relation to water deficit responses. We are currently in the process of experimentally validating these candidate genes with the aim to studying their function in water perception and responses.

Biography - Johannes Scharwies is a postdoctoral scholar in the group of Associate Professor José Dinneny at Stanford University in California. He is interested in how plants perceive and adapt to changes in the environment, particularly related to water. This ranges from developmental decisions to molecular control of water movement. In the group of José Dinneny, he is studying the phenomenon of hydropatterning, which describes the patterning of lateral root branches in response to spatial differences in water distribution in the root growth zone. He received his B.Sc. from Leibniz Universität Hannover, Germany, in 2010 and his M.Sc. and Ph.D. from The University of Adelaide in 2013 and 2018, respectively.