Growth-Promoting Bacteria Induce Salt Stress Tolerance in Strawberry Plants

Strawberry is a pseudofruit of great economic importance, and most of its production is carried out in a conventional system. However, abiotic stresses can affect the culture. Salt stress is one of the problems that can cause damage, and consequently impair the growth and productivity of the crop. Therefore, the objective of this study was to evaluate the influence of growth-promoting bacteria in mitigating the morphological effect of salt stress caused by NaCl in strawberry. The experiment consisted of six treatments, two controls (0 and saline) and four containing the bacteria (Pseudomonas fluorescens, Streptomyces sp., Rhizobium sp., Enterobacter sp.) plus 50 mM NaCl. Strawberry plants of cultivars Pircinque and PRA Estiva were inoculated with the bacteria and transferred to 2L pots containing commercial substrate plus 50 mM NaCl, where they remained for 90 days. Subsequently, aerial part and root length, number of leaves, fresh and dry mass, chlorophyll a, b, total and carotenoids were evaluated. The bacterium Streptomyces sp. stood out positively in all phytotechnical parameters analyzed. For the cultivar Pircinque, in terms of pigment content, the microorganism Enterobacter sp. stood out among all the others for all the analyzed pigments, while for the cultivar PRA Estiva there was a greater emphasis on the microorganism Rhizobium sp. in all analyzed pigments. The growth-promoting bacteria mitigated the effects of salinity on strawberry plants, making their growth and photosynthetic production not compromised by NaCl toxicity.