| dc.description.abstract | In agriculture, biostimulants derived from Ascophyllum nodosum extracts (ANE) have been widely used as growth stimulants and for protecting crops against biotic and abiotic stresses. Despite their widespread use, we have limited knowledge about how these biostimulants work and their role in influencing phytohormones throughout the plant. To shed light on this, we conducted a study using two commercial ANE biostimulants, Exelgrow (EG) and Exelmax (EM), which are produced through different methods. The main objective was to characterize and compare the effects of these biostimulants on the phenotype and hormonal signaling in Arabidopsis thaliana. Our findings reveal that EG and EM exhibit different biostimulant activity in Arabidopsis. Furthermore, EG promotes cytokinin (CK) signaling and suppresses auxin (AUX) signaling in the root meristem, while EM stimulates AUX and inhibits CK signaling. The transcriptomic analysis provided insights into their mechanism of action, revealing a priming effect against stress. EG interacts mainly with salicylic acid (SA) and jasmonate pathways, collectively regulating the plant's response to various biotic stresses. On the other hand, EM interacts with the brassinosteroids (BR) pathway, regulating ROS signals and defense against nematodes and pathogens. Finally, the transcriptomic analysis suggest that EM could be indirectly regulating AUX through the downregulation of BR signaling. | |
