Developing new biostimulant products is a multifaceted process that includes screening potential substances, investigating their modes of action, and conducting efficacy trials. Since biostimulants operate through diverse mechanisms, and their effectiveness is closely linked to these processes, it is crucial to analyse plant responses at multiple levels, including physiological, biochemical, and molecular aspects.
This study aimed to evaluate the physiological, transcriptomic, and metabolomic responses of wild rocket plants following the application of a biostimulant candidate.
Wild rocket plants (Diplotaxis tenuifolia L.) were cultivated in pots under controlled conditions. The product LG527, made from plant extracts and metabolites, was applied to leaves at a concentration of 50 µL/L. Physiological analyses were performed after three treatments (24, 48, and 96 hours post-treatment). Omic analysis included transcriptomic sampling at 24 hours and metabolomic sampling at 96 hours.
Results demonstrated a positive impact on photosynthetic performance, evidenced by the enhanced efficiency of photosystem II (Fv/Fm) and reduced energy dissipation (DIo/RC). The performance index (PI) increased in treated plants, supported by the modulation of genes related to photosynthesis. This effect was confirmed by the positive regulation of crucial photosynthesis genes (psbP and lhcb5). No significant changes were observed in chlorophyll content; however, treated plants exhibited an increase in sucrose at 48 hours and a decrease in reducing sugars at 96 hours. The treatment effectively reduced nitrate concentrations after 48 hours. This effect has been linked to the activation of biosynthetic amino acid pathways, as indicated by the increased expression of genes involved in nitrogen metabolism (glutamine synthetase and ribulose-phosphate 3-epimerase). Other significant modulations of genes involve calcium signalling and hormonal responses. The down-regulation of auxin and cytokine response regulators suggests an influence on plant growth and development.
The findings highlight LG527's potential as a biostimulant, reinforcing previous trials that demonstrated its efficacy in improving plant quality attributes and stress resilience. The collected data contribute to the formulation of potential usage claims.
