A Smoke Water-Mimetic Small Molecule Promotes Rice Root Elongation under Phosphorus Deficiency
DOI:
https://doi.org/10.48048/tis.2026.13701Keywords:
Salicylaldehyde, Smoke water, Phosphorus deficiency, Root elongation, Structure-activity relationship, RiceAbstract
Plant-derived smoke water enhances seedling growth across multiple species. However, the chemical basis of this activity remains poorly defined due to the complex mixtures and trace-level bioactives. The contribution of smoke-associated aromatic compounds to root responses under nutrient stress is particularly unclear. Here, we evaluated selected aromatic compounds in rice (Oryza sativa L. cv. Nipponbare) under phosphorus-sufficient and phosphorus-deficient conditions and performed structure-activity relationship (SAR) analyses across benzaldehyde and phenol derivatives. This study identified salicylaldehyde (SAL) as a defined bioactive that mimics smoke water-induced root elongation under phosphorus deficiency. SAR analysis indicated that low phosphorus-dependent root growth promotion may be associated with specific functional group combinations and substitution positions rather than general aromatic or phenolic properties. Antioxidant capacity did not correlate with root growth responses. Under salinity stress, SAL showed only modest root growth promotion and did not improve shoot growth or photosynthetic pigment status, indicating that its activity is strongly context dependent and does not confer enhanced performance under salinity stress. Together, these findings suggest that smoke-derived aromatic aldehydes, including SAL, can contribute to root developmental responses under nutrient-limiting conditions and provide a basis for further mechanistic investigation.
HIGHLIGHTS
- Salicylaldehyde selectively phenocopies smoke water-induced root elongation under phosphorus deficiency.
- Structure-activity relationship analysis shows that root growth promotion depends on specific functional group combinations and substitution positions.
- Root growth promotion by salicylaldehyde is independent of antioxidant capacity.
- Salicylaldehyde dose not confer improved performance under salinity stress.
- The activity of salicylaldehyde is highly context-dependent, highlighting the importance of environmental conditions in mediating root growth responses.
GRAPHICAL ABSTRACT
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