Adaptation of deep-rooted maize genotype to compacted soil: Synergy of root mechanical properties, anatomical traits, and PIEZO1 gene regulation

Deep-rooted maize plants utilize water and nutrients more effectively, particularly in compacted soil. However, the mechanisms by which different maize genotypes adjust root angles in response to compaction remain underexplored. We conducted a two-year study (2021–2022) on silty loam soils in the North China Plain. We tested two genotypes of maize [one with naturally deep roots (DR) and another with shallow roots (SR)] in compacted (C) and non-compacted (NC) soil. Soil compaction impeded shoot growth in both genotypes; however, DR exhibited better growth than SR. Under compacted conditions, DR maintained steeper root angles and demonstrated superior mechanical strength with larger root cortex areas (increased by 60 %) and stele (increased by 92 %), as well as higher cellulose concentration (up to 146 %). Notably, PIEZO1 gene expression increased significantly (up to 242 %) in DR under compaction, suggesting its role in root structural enhancement, unlike in SR where it remained unchanged. These findings underscore the importance of genetic, anatomical, and biochemical adaptations in maize roots, facilitating their resilience to soil compaction. Such insights could inform the breeding of maize genotypes that are better adapted to diverse soil conditions, potentially boosting agricultural productivity.