Alterações radiculares e metabólicas em Euterpe oleracea biopestimulada com Bacillus subtilis (UFRA 92)

Abstract

Biotic and abiotic stresses have impaired the growth and development of açaí (Euterpe oleracea Mart.) plants in the Amazon region. Therefore, research is underway to mitigate the effects of water scarcity and high nutritional demand that consequently promote slow initial growth. Some plant growth-promoting rhizobacteria (PGPR) have gained importance in agriculture to mitigate abiotic stress effects, highlighting their use as a sustainable strategy for agricultural production. However, the mechanisms of action of biostimulants are enigmatic, as different PGPRs can interact uniquely with the plant of interest, which is the main bottleneck for their use in the agricultural sector. The study objective was to evaluate the changes in primary metabolism (at the biochemical and physiological level) and subsequently characterize the changes in root architecture in acai plants' biostimulation with Bacillus subtilis. The experiment has been executed in a completely randomized design under nursery conditions with açaí seedlings inoculated with B. subtilis and non-inoculated seedlings. The metabolism of the acai plants, when inoculated with B. subtilis, showed stimulation of the biosynthesis of phytohormones, which consequently stimulated the photosynthetic machinery, resulting in greater nutrient uptake and the synthesis of primary compounds. It is noticeable the increase in the content of amino acids, organic acids, and soluble sugars that subsidized the mechanisms underlying growth promotion such as energy production and protein synthesis, that allows the development of plant growth in higher proportion compared to uninoculated plants. Resulting in the accumulation of root biomass, increase in surface area, and increase in the number of lateral root tips and ramifications. Key metabolites open study perspectives for the growth and development of plants that are more responsive to this type of input and, consequently, more adapted to adverse environmental conditions.