Understanding the Root Xylem Plasticity for Designing Resilient Crops

Abstract

Xylem is a main road in plant long-distance communication. Through xylem plants transport water, minerals and myriad of signaling molecules. With the onset during early embryogenesis, the development of xylem tissues relays on hormone gradients, activity of unique transcription factors, distribution of mobile miRNAs and receptor-ligand pathways. These regulatory mechanisms are often interconnected and all together contribute to the plasticity of water conducting tissue. Remarkably, root xylem carries water to all above-ground organs and therefore influences all aspects of plant growth. Because of the global warming and increasing water deficit, we need to come up with solutions for the crops of the future. It is clear that structure of water conducting elements directly impacts water transport within the plant. Among plant pathogens- vascular wilts attacking xylem -are the most harmful. Our knowledge about xylem anatomy and rewiring ability could bring the solutions against these diseases. In this review we summarize the recent findings on the molecular mechanisms of xylem formation with a special attention to the cellular changes, and cell wall rearrangements that are necessary to create functional capillaries. We emphasize the impact of abiotic factors and pathogens on xylem plasticity and discuss multidisciplinary approach to model xylem in crops.

Root phenotypes for the future

“…For example, architecture‐scale traits such as root angle can have a major impact on foraging efficiency for immobile and mobile soil nutrients such as phosphate and nitrate, respectively (Schneider et al, 2022). Increasing evidence supports the importance of anatomical‐scale traits, such as root hair length and xylem size, conferring abiotic stress tolerance in crops (Cai et al, 2022; Cornelis & Hazak 2022; Kohli et al, 2022), whilst major steps are being made to dissect molecular‐scale adaptive mechanisms, such as ways roots detoxify metals and metalloids (Kirk et al, 2022; Podar & Maathuis, 2022). Knowledge of these root phenotypes and their underlying regulatory genes is vital for developing future crop varieties better adapted to the challenges presented by global climate change and the pressing need to support more sustainable agricultural practices.…”

“…Whilst key root architectural traits have been identified as important for stress adaptation, the phenotypes of specific root cell types also play important roles in stress resilience. In this issue, Cornelis and Hazak (2022) review the function and regulation of root xylem development under environmental stress. Given that the xylem is the main route for transporting water and stress signals from root to shoots such new knowledge is urgently needed to underpin the design of climate‐resilient crops.…”