Rhizobacterial Isolates from Prosopis limensis Promote the Growth of Raphanus sativus L. Under Salt Stress

Abstract

Microbial biotechnology employes techniques that rely based on the natural interactions that occur in ecosystems. Bacteria, including rhizobacteria, play an important role in plant growth, providing agricultural crops with an alternative that can mitigate the negative effects of abiotic stress, such as those caused by saline environments. In this study, bacterial isolates were obtained from soil and roots of Prosopis limensis Bentham from the department of Lambayeque, Peru. This region has high salinity levels, therefore, the collected samples were used to isolate plant growth-promoting rhizobacteria (PGPR), which were identified through morphological, and physical-biochemical characteristics. These salt tolerant bacteria were screened phosphate solubilization, indole acetic acid, deaminase activity and molecular characterization by 16S rDNA sequencing. Eighteen samples from saline soils of the Prosopis limensis plants in the northern coastal desert of San Jose district, Lambayeque, Peru. The bacterial isolates were screened for salt tolerance ranging from 2 to 10%, a total of 78 isolates were found. Isolates 03, 13 and 31 showed maximum salt tolerance at 10%, in vitro ACC production, phosphate solubilization and IAA production. The three isolates were identified by sequencing the amplified 16S rRNA gene and were found to be Pseudomonas sp. 03 (MW604823), Pseudomonas sp. 13 (MW604824) and Bordetella sp. 31 (MW604826). These microorganisms promoted the germination of radish plants and increased the germination rates for treatments T2, T3 and T4 by 129, 124 and 118% respectively. The beneficial effects of salt tolerant PGPR isolates isolated from saline environments can be new species, used to overcome the detrimental effects of salt stress on plants. The biochemical response and inoculation of the three isolates prove the potential of using these strains as a source of products that can be employed for the development of new compounds proving their potential as biofertilizers for saline environments.

Potential Biofertilizers for Alkaline Soil: Bacteria Isolated from the Rhizosphere of Potatoes

“…Phosphorus and zinc solubilization are also approaches through which PGPR promote nutrient absorption. Among our seven strains of phosphorus-solubilizing bacteria, Leifsonia (ST172, ST177) [51], Curtobacterium (ST47) [52], Pseudomonas (ST4, ST18) [53] and Paenibacillu (ST22) [54] have been reported to be related to phosphorus solubilization, while the species L. aquatica (ST172) and L. naganoensis (ST177) and the genus Sutcliffiella (ST11) were the first-discovered to have this capability. Four isolates possessing a zinc-solubilizing ability were screened, and the genera Lysobacter (ST103) [55], Chryseobacterium (ST32) [56], Stenotrophomonas (ST34) [57] and Cellulosimicrobium (ST85) [37] have been reported to be zinc-solubilizing, but the species C. daecheongense (ST32) was the first reported to have this ability.…”