HyArchi · Targeting Root Hydraulic Architecture to improve Crops under Drought

Water is the most limiting environmental factor for agricultural production worldwide and climate change exacerbates this threat. The HyArchi project will address this issue from a plant biology perspective and proposes new strategies to improve crop tolerance to drought. The main objective is to optimize water uptake and transport in cereals affected by drought. HyArchi will target maize, a major crop and a foundational model in plant genetics and water relations that is grown in irrigation or rain-fed conditions. HyArchi will consider three root traits: root system architecture, generated through continuous growth and branching; water transport; and environmental signalling. The first two traits yield the root hydraulic architecture. HyArchi will investigate how this architecture evolves in time and space by integrating local and systemic signals that communicate water availability. HyArchi proposes two innovative molecular discovery approaches recently validated by my group in model plants. Genome-wide association studies will be used to uncover novel genes, with signalling functions acting on root hydraulics. Transcriptomic analyses of an experimental split-root system will be used to identify molecules (e.g. hormones, miRNAs) involved in systemic signalling and governing root growth and hydraulics. These studies will be supported by key methodological developments. A semi-automated set of pressure chambers will be constructed to measure root hydraulics in multiple genotypes under highly controlled local root environments. Improved root image analyses will be coupled to mathematical modelling to represent local and systemic effects of water on root hydraulic architecture. Ultimately, HyArchi will deliver enhanced knowledge on root water transport and its control by a set of new genes, with a description of their natural variation and impact on whole-plant drought responses. Importantly, this will allow introducing beneficial alleles into elite cultivars.