Growth stimulation of two legumes (Vicia faba and Pisum sativum) using phosphate-solubilizing bacteria inoculation

Abstract

The application of chemical fertilizers for plant growth and protection is one of the reasons for the environment and ecosystem destruction, thus, sustainable agriculture is gaining popularity in research and among farming communities. Although most soils are high in total phosphorus (P), a large portion is unavailable to plants and regarded as a growth-limiting factor. P-solubilizing bacteria (PSB) exploitation is a newly developed bio-solution for enhancing rhizosphere P availability; however, the effect of these bacteria on soil quality and the different phases of plant growth remains unknown. This study aims to evaluate the impact of five strains of PSB, isolated from legume rhizosphere, on the growth of two plants (Vicia faba and Pisum sativum) and certain soil properties. The efficient strains of PSB used are characterized by the P-solubilization, the ACC deaminase activity, the fixation of N, and the IAA, HCN, and siderophores production. The activity of these bacteria is tested in vitro and in vivo under controlled conditions on the growth of the two plants supplemented with the rock P (RP). According to our findings, all PSBs strains outperformed the control in terms of enhancing the growth of the tested legumes with a percentage ranging from 77.78 to 88.88%, respectively. The results showed that all treatments significantly improved plant parameters like nitrogen- (N) and P-content in the plants (67.50, 23.11%), respectively. Also, an increase in the fresh and dry weights of above- (41.17, 38.57%) and below-ground biomasses (56.6, 42.28%), respectively. Compared to the control, this leads to an increase of 72% in root length, 40.91% in plant dry weight, and 40.07% in fresh weight. Rhizospheric soil in PSBs treatments displayed high levels of N, P, and organic matter. All treatments were found to have significantly higher levels of alkaline phosphatase, basal soil respiration, and β-glucosidase activity than the control. It is concluded that multi-traits PSB can be an alternative for utilizing chemical fertilizers to enhance soil quality and plant growth. Despite the potency of PSBs, its use as a source for the development of sustainable agriculture implies focusing on crop species and adaptation, stress tolerance and climate resilience.

Phosphate-Solubilizing Bacteria: Advances in Their Physiology, Molecular Mechanisms and Microbial Community Effects

“…Note: In the table, "+" is a positive reaction result and "-" is a negative reaction result. Increase in dry weight [49] Wheat rhizosphere soil Bacillus safensis, Falsibacillus pallidus Root length, root surface area, root volume and number of root tips increased significantly [46] Maize rhizosphere soil S. marcensens, P. brenneri Substantial increase in maize production [50] Pulses Legumes in Fes-Meknes region rhizosphere soil PSB WJEF38 Agronomic traits of peas and broad beans were improved [51] Phaseolus vulgaris L. rhizosphere soil Pseudomonas kribbensis Biomass increased dramatically [13] Peanut rhizosphere soil Bacillus amyloliquefaciens Significant increase in aboveground dry and fresh weights [48] Horticultural crops Walnut, feijoa, jujube, apple rhizosphere soil Pantoea gavini, Acinetobacter sp.…”

“…However, high concentrations of nitrogen fertilizer can inhibit the growth and proliferation of PSB because nitrogen fertilizer application increases the nitrogen content of the soil, changes the nutrient environment and relative nitrogen-phosphorus ratios of soil microorganisms and decreases soil pH. PSB may be inhibited, which may lead to a decrease in their abundance [51,127,128]. Conversely, appropriate amounts of nitrogen reduction may be positive for the abundance of PSB communities [129].…”

Rhizospheric Bacteria of Cover Legumes from Acidic Soils Are Capable of Solubilizing Different Inorganic Phosphates

“…Furthermore, soil acidity can influence the activity of the rhizosphere bacterial community and the availability of other nutrients, further exacerbating nutritional problems in plants [ 9 ]. Improving the availability of phosphorus and other nutrients in acidic soils is important to ensure healthy plant growth and maximize agricultural productivity under these adverse conditions [ 10 ]. Given the importance of phosphorus in agriculture and soil recovery processes, the search for sustainable alternatives to phosphate fertilizers is essential to ensure adequate crop productivity [ 11 ].…”