Nanoselenium application improves post‐harvest fruit quality and disease resistance in tomato

Fruits constitute a vital component of a nutritious diet but are highly perishable, contributing substantially to food waste. Consequently, identifying safe and edible biological agents to enhance product quality and extend shelf life is of critical importance. In this study, we demonstrate that exogenous pre-harvest foliar application with nanoselenium (nano-Se) in tomato enhances fruit quality, prolongs fruit shelf life, and enhances the resistance of tomato fruit to Botrytis cinerea infection. Transcriptomic analysis revealed coordinated upregulation of genes associated with quality maintenance and modulation of phytohormone-related pathways. Notably, nano-Se treatment induced expression patterns of ripening-related genes that resembled those triggered by ethylene (ET) but were antagonistic to the effects of 1-MCP. We further demonstrated that although SlMYC2 knockout increased susceptibility to B. cinerea, nano-Se application restored resistance in a manner independent of the SlMYC2-associated jasmonic acid signaling pathway, implicating ET as the primary regulatory mechanism. Collectively, these findings support nano-Se as a promising biostimulant for reducing post-harvest losses while preserving the nutritional and sensory quality of tomato fruits.