Differential metabolic reprogramming and organ-specific antioxidant allocation in Oryza sativa and Echinochloa crus-galli under propanil-induced chemical stress.
TL;DR
It is suggested that resilience to chemical stressors may not rely solely on enzymatic detoxification, but may also involve coordinated, organ-specific metabolic buffering and targeted antioxidant reallocation.
Abstract
The physiological and metabolic mechanisms by which plants manage severe chemical stress during critical reproductive stages remain poorly understood. Here, we investigated the system-level phytotoxic responses and metabolic reprogramming of a tolerant species (Oryza sativa L.) and a susceptible species (Echinochloa crus-galli) exposed to the chemical stressor propanil using GC-MS/MS and LC-MS/MS. Under severe chemical stress, O. sativa maintained relatively stable antioxidant-related metabolism in grains, with α-tocopherol and phylloquinone showing only modest decreases of 0.86- and 0.90-fold, respectively. β-Sitosterol oryzanol was also preserved or increased in rice tissues, showing 1.05-fold in grain and 1.48-fold in husk, whereas it was not detected in E. crus-galli. In contrast, E. crus-galli exhibited stronger antioxidant perturbation, with α-tocopherol decreasing to 0.57-fold in grain and 0.72-fold in husk and (all-E)-zeaxanthin accumulating markedly in grain by 5.30-fold. Furthermore, the non-detection of oryzanol esters in E. crus-galli highlights a fundamental biochemical limitation in its oxidative stress defense. Ultimately, these findings suggest that resilience to chemical stressors may not rely solely on enzymatic detoxification, but may also involve coordinated, organ-specific metabolic buffering and targeted antioxidant reallocation.