Unlocking the interactive role of GABA and NO in alleviating chlorpyrifos induced toxicity in Solanum melongena L. through modulation of physio-biochemical traits.

Injudicious application of pesticides has a detrimental effect on vegetable productivity and food safety. Gamma-aminobutyric acid (GABA) and nitric oxide (NO) are key signaling molecules known to exhibit crosstalk in plant stress responses; however, their interaction under chlorpyrifos (CP) stress in eggplant (Solanum melongena L.) remains unexplored. Their synergistic action is essential for maintaining redox balance and enhancing stress resilience. Thus, the present study evaluates the effect of exogenous GABA and NO, individually and in combination (GABA + NO), on growth, physiological and biochemical attributes of eggplant seedlings under CP stress. CP stress significantly reduced the growth attributes (48% biomass, 21% stomatal density and 15% trichome density), pigments (35% Chl a and 44% Chl b with 27% rise in Car), and photosynthetic performance (34% A, 9% Fv/Fm, and 52% PIABS with an increase of 37% in DI0/RC), while oxidative biomarkers (100% O2●-, 147% H2O2 and 114% MDA) were exacerbated as compared to control (CK). Exogenous GABA and NO together increased growth attributes (6% biomass, 17% stomatal density and 21% trichome density), pigments (24% Chl a and 18% Chl b with 20% decreased in Car) and photosynthetic performance (16% A, 6% Fv/Fm and 37% PIABS, with a reduction of 21% in DI0/RC) as compared to control. This alleviating effect could be attributed to GABA-NO mediated regulation of ROS detoxification by increased activity of catalase, superoxide dismutase, peroxidase and glutathione-s-transferase, and also by stabilization of photosynthetic machinery. Inhibitors/scavenger (MPA, L-NAME, and c-PTIO) elevated stress impact with a stronger effect of MPA, indicating the dominant role of GABA. The findings reveal that GABA-NO interaction plays a crucial role in mitigating CP toxicity through regulation of antioxidants and photosynthetic machinery, providing a potential strategy to enhance crop tolerance under pesticide stress.