Plants breathing under pressure: mechanistic insights into soil compaction-induced physiological, molecular and biochemical responses in plants.

This review highlights the molecular, biochemical and physiological responses of plants under soil compaction and presents suitable strategies for optimizing soil compaction for sustainable and intelligent plant production. Soil compaction (SC) increases the mechanical impedance of agricultural crops, which restricts plant growth, root elongation, and productivity. Therefore, exploring the impacts of SC-induced alterations in plants and developing optimization strategies are crucial for sustainable agricultural production and ensuring global food security. However, the regulation of molecular, biochemical and physiological responses to SC in plants has not yet been well explored. Here, we conducted a thorough analysis of the relevant literature regarding the primary factors behind SC in agricultural soils, mechanistic insights into SC-mediated molecular and physiological alterations in plants, the impact of SC on plant productivity, and SC-minimization strategies for eco-friendly and intelligent agricultural production. The existing information suggests that plant roots sense SC-induced changes in soil properties, including decreased soil water content, hypoxia, nutrient deficiency and mechanical stimuli, through altering the expression of membrane-located ion channel- or stimulus receptor-related genes, such as MSLs, MCA1, and AHK. After signal transduction, the synthesis and transport of several plant hormones, mainly ABA, ethylene and auxin, change and restrict root deepening but promote root thickening. In addition, the changes in plant hormones in combination with decreased water availability and decreased root hydraulic conductance induced by SC affect aboveground physiological responses, such as decreasing leaf hydraulic conductance, promoting stomatal closure and inhibiting plant photosynthesis. Comprehensive physiological insights into SC in plants and SC optimization strategies could be useful to soil biologists and plant eco-physiologists seeking to improve soil management and sustainable agricultural plant production to promote global food security.