Potential of mineral-solubilizing bacteria for physiology and growth promotion of Chenopodium quinoa Willd

Abstract

Nutrient deficiency in wild plant species, including quinoa (Chenopodium quinoa Willd), can be overcome by applying mineral-solubilizing bacteria. Quinoa is a gluten-free, nutritious food crop with unique protein content. The present study aimed to characterize mineral-solubilizing rhizobacterial strains and to evaluate their plant growth-promoting potential in quinoa seedlings. More than sixty rhizobacterial strains were isolated from the quinoa rhizosphere and found eighteen strains to be strong phosphate solubilizers. Most of these bacterial strains showed zinc solubilization, and more than 80% of strains could solubilize manganese. The selected strains were identified as Bacillus altitudinis Cq-3, Pseudomonas flexibilis Cq-32, Bacillus pumilus Cq-35, Pseudomonas furukawaii Cq-40, Pontibacter lucknowensis Cq-48, and Ensifer sp. Cq-51 through 16S rRNA partial gene sequencing. Mainly, these strains showed the production of organic acids, including malic, gluconic, tartaric, ascorbic, lactic, and oxalic acids in insoluble phosphorus amended broth. All strains showed production of gluconic acids, while half of the strains could produce malic, ascorbic, lactic, and oxalic acids. These strains demonstrated the production of indole-3-acetic acid in the presence as well as in the absence of L-tryptophan. The bacterial strains also demonstrated their ability to promote growth and yield attributes, including shoot length, root length, leave numbers, root and shoot dry biomass, spike length, and spikes numbers of quinoa in pots and field trials. Increased physiological attributes, including relative humidity, quantum flux, diffusive resistance, and transpiration rate, were observed due to inoculation with mineral solubilizing bacterial strains under field conditions. P. lucknowensis Cq-48, followed by P. flexibilis Cq-32, and P. furukawaii Cq-40 showed promising results to promote growth, yield, and physiological attributes. The multi-traits characteristics and plant growth-promoting ability in the tested bacterial strains could provide an opportunity for formulating biofertilizers that could promote wild quinoa growth and physiology.

Mineral-Solubilizing Bacteria-Mediated Enzymatic Regulation and Nutrient Acquisition Benefit Cotton’s (Gossypium hirsutum L.) Vegetative and Reproductive Growth

“…Inoculation with bacterial strains enhances growth and growth-related attributes of cotton, owing to different direct and indirect growth-promoting traits. In present studies, co-inoculation with phosphate and Zn solubilizing strains enhanced growth and yield parameters of cotton crop that might be due to catalase activity, urease activity, phytohormone production, exopolysaccharides production [59] and siderophore production [60] by these strains that caused effective colonization of cotton roots by these strains leading to reach more nutrients (Zn, P) [61,62]. The plant growth-promoting abilities of Bacillus strains have already been reported in our previous study [28].…”

“…They solubilized more nutrients and performed more functions according to their capabilities, which favored plant growth and yield attributes. Rafique et al [62] characterized PGPB strains as promising multifarious mineral solubilizers, demonstrating an increase in quinoa's growth and physiology. Li et al [63] also reported that the combined application of mineral solubilizing PGPB strains promoted nutrient availability in soil and root growth of Robinia pseudoacacia through promoting mineral solubilization and enzymatic activities.…”

Geographically Disperse, Culturable Seed-Associated Microbiota in Forage Plants of Alfalfa (Medicago sativa L.) and Pitch Clover (Bituminaria bituminosa L.): Characterization of Beneficial Inherited Strains as Plant Stress-Tolerance Enhancers

“…and Paenibacillus sp.) were also described previously as pathogen controllers inherited from seeds [ 74 , 76 , 95 , 96 , 97 , 98 ]. Additionally, some of these strains were previously identified as part of the seed microbiota in previous studies ( P. tundrae , P. megaterium and P. megaterium ).…”

Isolation and characterization of phosphate-solubilizing bacterium Pantoea rhizosphaerae sp. nov. from Acer truncatum rhizosphere soil and its effect on Acer truncatum growth

“…Phosphorus (P) is an essential macronutrient for plant survival and reproduction, as a component of nucleic acids, membrane phospholipids and many energy-dependent metabolic processes (Vance et al, 2003). Phosphorus is frequently the most limiting element in soils because it rapidly forms insoluble complexes with cations and has low solubility and poor mobility in soils (Hinsinger, 2001;Rafique et al, 2022). The total amount of P is quite abundant in many soils, ranging from 0.02% to 0.5% (w/w), with an average of about 0.05% (w/w) (Son et al, 2006).…”

“…Rhizobacteria are plant-associated bacteria that colonize and persist in the proximity of roots or inside the root tissues (Backer et al, 2018). Phosphate-solubilizing bacteria (PSB) have the capacity to convert insoluble inorganic phosphates into soluble forms available to plants (Rafique et al, 2022). The principal mechanism for mineral P solubilization by PSB is associated with the production of low-molecular-weight organic acid anions, which through their hydroxyl and carboxyl groups chelate the phosphate-bound cations to liberate P in soluble forms (Hassan et al, 2019).…”