A new biostimulant formulation (APH-1035; alkaline Ascophyllum nodosum seaweed extract and amino acid, L-phenylalanine) was evaluated in mode of actions studies to understand the contribution of each active ingredient to the effect of the biostimulant. Previous controlled environment studies showed under salinity and drought stress, plants treated with this new biostimulant had an increase in shoot weight and leaf area, and improvements in photosynthetic parameters, showing statistical synergy between the active ingredients. Field trials had similar results with treated plants having an increase foliar and root fresh and dry weight, and yield under drought and salinity stress. An increase in flowers and fruit set was also seen. Controlled environment studies evaluated the potential mode of action of APH-1035 on strawberry under drought stress. Treatments consisted of a non-stressed control, a stressed control, APH -1035, and the individual active ingredients in APH-1035 (seaweed extract, and phenylalanine) at the equivalent concentrations in APH-1035. Leaf tissue samples were collected pre-stress, and two time points post stress, frozen, and RNA extracted, followed by RNASeq, and subsequent data analysis. Plants treated with APH-1035 showed a transcriptional profile more similar to the non-stressed plants than stressed control plants. The individual active profiles were more similar to the stressed control. Transcript abundance increased over time and did not change after prolonged drought stress. In contrast, stressed control plants, showed down regulation of this gene cluster. Correlation analysis resulted in 221 genes whose expression correlated significantly with treatments. Some of these genes are related to photosynthesis and starch metabolism, which can be linked to drought resistance. These results suggest that the novel biostimulant, with the combination of seaweed extract and an amino acid (phenylalanine) influences gene expression within plants to reduce abiotic stress and promote growth and metabolism under stress, and that this response is greater than the individual actives alone.
