Foliar application of wood distillate mitigates ozone-sensitive Phaseolus vulgaris L. (cv. S156) from ozone phytotoxicity

Tropospheric ozone (O3) is a major constraint for agriculture, causing oxidative stress, accelerated leaf senescence, and yield losses in sensitive crops. To develop sustainable alternatives to synthetic protectants, bio-based products derived from circular economy processes have gained attention.However, their impact on plant productivity and seed quality remains poorly understood. Here, we tested whether foliar applications of a commonly used wood distillate (WD) concentration (0.2%) could protect the O3-sensitive P. vulgaris (cv. S156), grown in a Free air O3 eXposure (FO3X) system under ambient air (AA; Accumulated exposure Over Threshold of 40 ppb = 4,093 ppb h), 1.5×AA (10,629 ppb h), and 2.0×AA (18,654 ppb h) conditions. Across all O3 exposure levels, WD reduced visible foliar injury (−53%, globally) and improved photosynthetic performance by enhancing net photosynthetic rate (+15%, under 1.5×AA) and pigment concentrations (i.e., antheraxanthin, under both 1.5 and 2.0×AA). It also reshaped hormonal signaling by increasing jasmonic acid and reducing abscisic acid, suggesting a shift from stomatal closure to jasmonate-mediated defenses, despite higher hydrogen peroxide levels. Importantly, WD enhanced seed yield (+12%) and improved nutritional quality by increasing soluble protein content (+19%) and sucrose (+28%), while reducing glucose (−27%), consistent with improved seed differentiation and reserve accumulation. These findings demonstrate that WD mitigates O3-induced foliar injury and supports photosynthetic performance under elevated O3, improving nutritional traits and seed yield across O3 treatments, although the response is not exclusively to O3 protection. Wood distillate thus represents a low-cost and ecofriendly tool to mitigate injuries and improve crop performance under ambient and elevated O3.