Abstract
Microbial biotechnology employs techniques that rely on the natural interactions that occur in ecosystems. Bacteria, including rhizobacteria, play an important role in plant growth, providing crops with an alternative that can mitigate the negative effects of abiotic stress, such as those caused by saline environments, and increase the excessive use of chemical fertilizers. The present study examined the promoting potential of bacterial isolates obtained from the rhizospheric soil and roots of the Asparagus officinalis cultivar UF-157 F2 in Viru, la Libertad, Peru. This region has high soil salinity levels. Seventeen strains were isolated, four of which are major potential plant growth-promoting traits, and were characterized based on their morphological and molecular characteristics. These salt-tolerant bacteria were screened for phosphate solubilization, indole acetic acid, deaminase activity, and molecular characterization by 16S rDNA sequencing. Fifteen samples were from saline soils of A. officinalis plants in the northern coastal desert of San Jose, Lambayeque, Peru. The bacterial isolates were screened in a range of salt tolerances from 3 to 6%. Isolates 05, 08, 09, and 11 presented maximum salt tolerance, ammonium quantification, phosphate solubilization, and IAA production. The four isolates were identified by sequencing the amplified 16S rRNA gene and were found to be Enterobacter sp. 05 (OQ885483), Enterobacter sp. 08 (OQ885484), Pseudomonas sp. 09 (OR398704) and Klebsiella sp. 11 (OR398705). These microorganisms promoted the germination of Zea mays L. plants, increased the germination rates in the treatments with chemical fertilizers at 100% and 50%, and the PGPRs increased the height and length of the roots 40 days after planting. The beneficial effects of salt-tolerant PGPR isolates isolated from saline environments may lead to new species that can be used to overcome the detrimental effects of salt stress on plants. The biochemical response and inoculation of the three isolates prove the potential of these strains as sources of products to develop new compounds, confirming their potential as biofertilizers for saline environments.