Comparison of the effect of organic versus non-organic biostimulants application on plant growth and transcriptome analysis of cucumber plants

Nowadays modern agriculture systems are challenged by adopting sustainable and eco-friendly practices to boost crop yield while reducing chemical usage. In this context, the application of biostimulants has emerged as a promising solution. This study compares the efficacy of organic (Lombrico®) and non-organic (Nobrico®) biostimulants on cucumber plants under hydroponic conditions in a plant growth chamber. For this purpose, vegetative growth parameters (number of leaves, width of the main stalk, plant height, root length and volume, number of root ramifications, fresh and weight of shoots and roots), mineral concentration in leaves and RNA-Sequencing analysis parameters were evaluated. Results demonstrated that root application of both biostimulants improved the growth development and modified root system architecture. In shoots, the organic system increased plant height by 18 %, dry weight by 75 %, and leaf number by 26 % with respect to the control, while the non-organic biostimulant increased plant height by 14 % and leaf number by 19 %. In the roots, both products promoted lateral root development and inhibited primary root elongation, with the organic biostimulant showing more pronounced effect, resulting in a 122 % increase in root volume and a 42 % in the number of ramifications compared to the non-organic treatment. These physiological modifications were attributed to the bioactive compound of each formulation, particularly amino acid, seaweed extract, and carbohydrate. Transcriptome analysis revealed that these synergies of these bioactive compounds affected phytohormones homeostasis, encompassing receptors, signaling elements, and transcription factors, which together facilitate the interaction in root development. These improvements in plant growth response confirm that the organic system showed better effects compared to the non-organic biostimulant.

The first author received a scholarship from predoctoral training in collaboration with companies thought the R&D & i promotion program of the Vice-Rectorate for Research of the University of the Alicante 2021 (UAIND21-13B). The authors acknowledge Alfredo Iñesta S.L for providing organic biostimulant.