Native bacteria as sustainable biofertilisers for periurban horticulture soils’ quality restoration

Abstract

The impact produced by agrochemicals on periurban agriculture soils generates an environmental concern. The objective of this work was to evaluate the potential of native plant growth-promoting bacteria to recover the horticultural soil quality for bioinoculant design using Eisenia andrei as bioindicator. Total phosphorus determination and bioassays with E. andrei cholinesterases, carboxylesterases and glutathione S-transferases as biomarkers were performed. Glutathione S-transferase levels were significantly augmented (~ 30%) evidencing the risk of uncontrolled use of agrochemicals. Native Pseudomonas migulae S1-2, Sphingobium yanoikuyae SP-3 and Leucobacter aridicollis RP-7 exhibited plant growth-promoting properties. Indole-3-acetic acid production of 14.0 ± 0.1, 69 ± 1 and 6.4 ± 0.1 µg mL−1 and phosphorus solubilisation of 46, 133 and 158 mg P L−1 were obtained from culture supernatants. Bacterial supernatants increased the root elongation of Lactuca sativa seeds up to 10%. These selected bacteria demonstrated their potential to design a biofertiliser formulation to restore deteriorated horticultural soils.