Rhizospheric Phosphate Solubilizing Bacillus atrophaeus GQJK17 S8 Increases Quinoa Seedling, Withstands Heavy Metals, and Mitigates Salt Stress

Abstract

Introduction of quinoa (Chenopodium quinoa willd.), a gluten-free nutritious pseudo-cereal, outside its traditional growing areas exposed it to seedling damping-off. Here, we isolated eleven phosphate-solubilizing bacteria from the quinoa rhizosphere and assessed their effect on germination and seedlings growth. All isolates solubilized phosphate, produced indole3-acetic acid, hydrocyanic acid, siderophores, and ammonia. Genotypic analysis revealed that our strains are related to the genus of Bacillus, Pseudomonas, and Enterobacter. Strains Enterobacter asburiae (QD14, QE4, QE6, and QE16), Enterobacter sp. QE3, and Enterobacter hormaechei QE7 withstood 1.5 mg·L−1 of cadmium sulfate, 0.5 mg·mL−1 of nickel nitrate, and 1 mg·mL−1 of copper sulfate. Moreover, all strains solubilized zinc from ZnO; P. Stutzeri QD1 and E. asburiae QD14 did not solubilize Zn3(PO4)2 and CO3Zn, whereas CO3Zn was not solubilized by E. asburiae QE16. Bacillus atrophaeus S8 tolerated 11% NaCl. P. frederiksbergensis S6 and Pseudomonas sp. S7 induced biofilm formation. Anti-fusarium activity was demonstrated for E.asburiae QE16, P. stutzeri QD1, P. frederiksbergensis S6, Pseudomonas sp. S7, and B. atrophaeus S8. Lastly, inoculation of quinoa seeds with B. atrophaeus S8 and E. asburiae QB1 induced the best germination rate and seedling growth, suggesting their potential use as inoculants for salty and heavy metal or zinc contaminated soils.

Cupressus arizonica Greene: Phytochemical Profile and Cosmeceutical and Dermatological Properties of Its Leaf Extracts

“…This could be useful in weakening bacterial pathogenicity by destroying biofilm and reducing the spread of infections. Similar findings were described before for extracts rich in polyphenols, such as those from Salix tetrasperma flowers and bark [ 30 ], Ximenia americana leaf [ 30 , 31 ] and Lavandula coronopifolia aerial parts [ 32 ].…”

“…The effects of the sub-MIC concentrations of C. arizonica aqueous and ethanolic leaf extracts on biofilm formation by P. aeruginosa were determined using the crystal violet colorimetric assay [ 30 , 31 ]. Briefly, the extracts at the doses of 1/8 MIC and 1/4 MIC were prepared in MH broth, filtered using 0.22 μm syringe filters, inoculated, and incubated as described above in the MIC assay.…”

Phytochemical Profiling of the Leaf Extract of Ximenia americana var. caffra and Its Antioxidant, Antibacterial, and Antiaging Activities In Vitro and in Caenorhabditis elegans: A Cosmeceutical and Dermatological Approach

“…The antibiofilm potential of the extract was assessed using a colorimetric assay [ 24 , 25 ]. Firstly, the extract at the doses of 3.13 mg/mL (1/8 MIC) and 6.25 mg/mL (1/4 MIC) was prepared in Mueller Hinton (MH) broth and then filtered using 0.22 μ m syringe filters.…”

Antibiotic resistance in plant growth promoting bacteria: A comprehensive review and future perspectives to mitigate potential gene invasion risks

“…Similarly, Serratia rubidaea ED1 strain, an opportunistic pathogenic bacterium, isolated from quinoa roots endosphere was found resistant to seven antibiotics ( Mahdi et al, 2021b ). In addition, out of 11 PSB isolated from quinoa rhizosphere, five strains showed resistance to at least two antibiotics ( Mahdi et al, 2021a ). More recently, antibiotic resistance mechanisms were studied in biofertilizer samples following application into the soils, these include mainly antibiotic deactivation (48.7%), efflux pumping (25.2%), cellular protection (18.0%), and other unknown mechanisms (8.1%; Yang et al, 2022 ).…”