Stimulatory potential of Pseudomonas sp. isolates on the initial growth of sage (SALVIA OFFICINALIS L.)

Sage (Salvia officinalis L.) is considered a functional food that has many other uses in medicine, cosmetics, and the food industry, among others. It grows in the wild but is also widely cultivated for human consumption. The application of plant growth-promoting (PGP) microbes in sage production can be a sustainable eco-friendly production measure contrasted to traditional systems where chemical-based management practices are used. Moreover, the usage of different products of microbial origin is constantly increasing due to growing awareness of the potentially harmful effects of artificial substances in food. Pseudomonads are well-known bacteria with PGP traits. Phytohormone production, nitrogen fixation, phosphorus solubilization, and iron sequestration by siderophores are only a few mechanisms of growth promotion. The aim of this study was to evaluate the efficiency of Pseudomonas sp. isolates (denoted as P8, P37, and P53) on seed germination and the initial growth of sage in semi-controlled conditions for four weeks. Morphological, physiological, biochemical, and PGP characterization of bacteria isolates were performed prior to the study. All isolates demonstrated a good ability to produce siderophore and solubilize phosphorus, while only P53 produced hydrogen cyanide (HCN). Seed inoculation led to better germination and the initial growth of sage. Seedling development was stimulated, reaching a maximum of 57 mm in treatment P53 after 5 days. On average, a 21% increase was achieved with P37 and P53 in relation to the untreated control. Regarding root length and plant height, the inoculated plants were 2.4 to 3.4 and 1.2 to 1.5-fold larger in size, respectively. All isolates showed stimulatory potential, positively influencing the initial growth of sage. The best stimulatory potential was achieved with P37. Pseudomonas sp. isolates proved to have good bio-stimulatory potential and can be used in sage production.