Pulsed Light as a Physical Defense Elicitor in Tomato cv. Marmande: Enhancing Defense Responses and Reducing Botrytis Infection

The trade-off between reducing pesticide use and ensuring effective crop protection is a key challenge for sustainable agriculture. Stimulating the plant’s natural defense mechanisms represents a promising alternative. In this study, we evaluated the potential of pulsed light as a physical elicitor in tomato (Solanum lycopersicum). This technology is based on the emission of brief but intense light flashes, covering a broad spectrum (from UV-C to infrared), capable of simultaneous activation of multiple signaling pathways. Tomato plants were treated using a standard protocol and subjected to biochemical, transcriptional, physiological, and pathological analyses. The treatment significantly increased the activity of defense-related and antioxidant enzymes, the accumulation of phenolic compounds and callose, and the expression of key immunity-related genes. Upon Botrytis cinerea inoculation, pretreated tomato plants showed enhanced defense responses and a significant reduction in disease severity, indicating a priming effect. The standard protocol did not impair photosynthesis, growth, or yield. These findings highlight pulsed light as an innovative technology for integrated crop protection.