Pseudomonas simiae WCS417 Strain Enhances Tomato (Solanum lycopersicum L.) Plant Growth Under Alkaline Conditions

Iron (Fe) deficiency is among the most important agronomical concerns under alkaline conditions. Bicarbonate is considered an important factor causing Fe deficiency in dicot plants, mainly on calcareous soils. Current production systems are based on the use of high-yielding varieties and the application of large quantities of agrochemicals, which can cause major environmental problems. The use of beneficial rhizosphere microorganisms is considered a relevant sustainable alternative to synthetic fertilizers. The main purpose of this work has been to analyze the impact of the inoculation of tomato (Solanum lycopersicum L.) seedlings with the WCS417 strain of Pseudomonas simiae, in the presence or absence of bicarbonate, on plant growth and other physiological parameters. To conduct this research, three different inoculation methods were implemented: root immersion, foliar application, and substrate inoculation by irrigation. The results obtained show the ability of the P. simiae WCS417 strain to induce medium acidification in the presence of bicarbonate to increase the SPAD index and to improve the growth and development of the tomato plants in calcareous conditions provoked by the presence of bicarbonate, which indicates that this bacteria strain could have a great potential as an Fe biofertilizer.