Amelioration of salt stress in broccoli seeds by an innovative biostimulant based on orange carrot cell cultures

Adverse edaphoclimatic conditions resulting from climate change pose a serious threat to global food production, as they hinder plant development and reduce crop yields. Among these stress factors, soil salinization is one of the major constraints affecting seed germination, a critical stage in the crop life cycle. Seed priming has emerged as an effective strategy to enhance germination under stress conditions, particularly when employing higher plant-derived biostimulants (hPDBs), which are notable for their rich composition of bioactive compounds and their ability to modulate plant physiology. In this work, we produced an orange carrot cell culture-derived biostimulant (OCB) through elicitation techniques, resulting in a product enriched in phytosterols and phenolic compounds, and evaluated its effect on the germination of broccoli seedlings subjected to salt stress. OCB improved seed germination and vitality, avoiding H 2 O 2 accumulation and reducing the oxidative stress-induced damage (-11 % MDA) and toxicity of salt stress. This allowed to prevent an aggressive response to stressful conditions which could worsen the germination process, thereby attenuating the disruption in the hormonal and proteomic profile induced under salt stress by downregulating the accumulation of stress-related hormones and antioxidant enzymes. Thus, OCB constitutes a novel plant biostimulant with significant potential to promote seed vigour and germination efficiency in broccoli under salinity stress.