Pseudomonas rhizophila S211, a New Plant Growth-Promoting Rhizobacterium with Potential in Pesticide-Bioremediation

Abstract

A number of Pseudomonas strains function as inoculants for biocontrol, biofertilization, and phytostimulation, avoiding the use of pesticides and chemical fertilizers. Here, we present a new metabolically versatile plant growth-promoting rhizobacterium, Pseudomonas rhizophila S211, isolated from a pesticide contaminated artichoke field that shows biofertilization, biocontrol and bioremediation potentialities. The S211 genome was sequenced, annotated and key genomic elements related to plant growth promotion and biosurfactant (BS) synthesis were elucidated. S211 genome comprises 5,948,515 bp with 60.4% G+C content, 5306 coding genes and 215 RNA genes. The genome sequence analysis confirmed the presence of genes involved in plant-growth promoting and remediation activities such as the synthesis of ACC deaminase, putative dioxygenases, auxin, pyroverdin, exopolysaccharide levan and rhamnolipid BS. BS production by P. rhizophila S211 grown on olive mill wastewater based media was effectively optimized using a central-composite experimental design and response surface methodology (RSM). The optimum conditions for maximum BS production yield (720.80 ± 55.90 mg/L) were: 0.5% (v/v) inoculum size, 15% (v/v) olive oil mill wastewater (OMWW) and 40°C incubation temperature at pH 6.0 for 8 days incubation period. Biochemical and structural characterization of S211 BS by chromatography and spectroscopy studies suggested the glycolipid nature of the BS. P. rhizophila rhamnolipid was stable over a wide range of temperature (40–90°C), pH (6–10), and salt concentration (up to 300 mM NaCl). Due to its low-cost production, emulsification activities and high performance in solubilization enhancement of chemical pesticides, the indigenous BS-producing PGPR S211 could be used as a promising agent for environmental bioremediation of pesticide-contaminated agricultural soils.

Novel Bioformulations Developed from Pseudomonas putida BSP9 and Its Biosurfactant for Growth Promotion of Brassica juncea (L.)

“…For purification, thin layer chromatography (TLC) was done and the analysis of the two extracted major spots (retention factor Rf = 0.33 and Rf = 0.78) ( Supplementary Materials, Figure S3 ) showed mobility similar to that of glycolipids [ 46 , 47 ]. The spot nearest to the point of origin (Rf = 0.33) represented di-rhamnolipid while the spot further away from the point of origin (Rf = 0.78) corresponded to mono-rhamnolipid [ 48 , 49 ]. Biosurfactants have gained special attention in recent times owing to their wide range of applications, operational flexibility, low toxicity and ecofriendly nature [ 50 ].…”

Pseudomonas aeruginosa RTE4: A Tea Rhizobacterium With Potential for Plant Growth Promotion and Biosurfactant Production

“…Recently, PGP Pseudomonas sp. producing BS was isolated from pesticide contaminated field (Hassen et al, 2018) and from the roots of common reed having hydrocarbon degrading potential (Wu et al, 2018). Thus, from literature it appears that Pseudomonas strains are one of the promising microbial systems which can be exploited for production of surface active agents.…”

Isolation and Proto-cooperation of Pseudomonas putida TS 18 from Water Calyx Fluid of Spathodea campanulata P. Beauv.

“…Among which Bacillus and Pseudomonas forms are predominate (Podile, 2006) and one such dynamic plant growth promoting bacteria belongs to genus Pseudomonas which is heterogeneous and ecologically significant group among bacteria (Tasic et al 2014). Various species of Pseudomonas are widely used as bioinoculant, biofertilization and phytostimulation (Wafa et al 2018). They are known to inhabit foliar surfaces, root surfaces, intercellular spaces in leaves and roots.…”