Periodic Reporting for period 4 - HyArchi (Targeting Root Hydraulic Architecture to improve Crops under Drought)
Reporting period: 2023-04-01 to 2024-09-30
Water is the most limiting environmental factor for agricultural production worldwide and climate change exacerbates this threat. The HyArchi project addressed this issue from a plant biology perspective and proposed new strategies to improve crop tolerance to drought.
The main objective was to optimize water uptake and transport in cereals affected by drought. HyArchi targetted maize, a major crop and a foundational model in plant genetics and water relations that is grown in irrigation or rain-fed conditions.
HyArchi considered 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 investigated how this architecture evolves in time and space by integrating local and systemic signals that communicate water availability. The project allowed identifying several genes that control either root architecture (seminal root number) or root hydraulics. The impact of some of these genes on shoot water relations was established in plants under drought.
The main objective was to optimize water uptake and transport in cereals affected by drought. HyArchi targetted maize, a major crop and a foundational model in plant genetics and water relations that is grown in irrigation or rain-fed conditions.
HyArchi considered 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 investigated how this architecture evolves in time and space by integrating local and systemic signals that communicate water availability. The project allowed identifying several genes that control either root architecture (seminal root number) or root hydraulics. The impact of some of these genes on shoot water relations was established in plants under drought.
More specifically, root system architecture and root hydraulic properties were analyzed in maize seedlings subjected to water deficit. Inhibitory effects on root growth, lateral root formation and root hydraulics revealed root-type specific responses to water deficit. A transcriptomic analysis (RNAseq) revealed the role of key gene regulatory networks and plant hormones in systemic responses of roots to heterogeneous water deficit. In addition, improved water transport measurements and root image analyses were coupled to mathematical modelling to represent effects of water deficit on root hydraulic architecture of contrasting maize genotypes. In parallel, a genetic dissection of seminal root number and root hydraulics was performed using Genome Wide Association Studies. Seven genes associated to phenotypic variations were validated using recombinant populations, insertion mutagenesis or genome edition. High-throughput phenotyping of genetic materials altered in their root hydraulic architecture revealed altered stomatal responses under varying drought scenarios. The results of the HyArchi projects have been disseminated through international scientific journals, conferences and meetings of plant scientists and breeders.
Ultimately, HyArchi delivered enhanced practical and theoretical knowledge on root water transport and its control by a set of new plant genes. As anticipated, some of these genes can influence the response of whole plants to drought. Importantly, the natural variation of these genes in maize may provide an interesting source of beneficial alleles for introduction into elite cultivars.