Plant Growth-Promoting Rhizobacteria Promote Growth of Seedlings, Regulate Soil Microbial Community, and Alleviate Damping-Off Disease Caused by Rhizoctonia solani on Pinus sylvestris var. mongolica

Abstract

As the excessive use of chemical fertilizers harms organisms and adversely affects the soil environment, the replacement of chemical fertilizers with biological fertilizers has attracted widespread attention as an environmental protection strategy. In this study, the effects of rhizosphere bacteria inoculation on growth of Pinus sylvestris var. mongolica seedlings, soil parameters, soil microbial community structure, and the biocontrol of damping-off were studied by pot experiments. The results showed that all three rhizosphere bacteria (Pseudomonas chlororaphis, Pseudomonas extremaustralis, and Acinetobacter lwoffii A07) tested exhibited growth-promoting properties, such as the production of indole-3-acetic acid, hydrolase, siderophores, and hydrogen cyanide; nitrogen fixation; and phosphorus solubilization. The application of the three bacteria increased plant biomass, root structure, and nutrient content and also increased soil nutrient content and enzyme activity. Bacterial inoculation promoted the growth of beneficial bacteria and antagonistic bacteria by adjusting the physicochemical properties of the soil, thereby improving the bacterial community structure. Among the soil features, available nitrogen, total nitrogen, available potassium, and urease activity were the main influencing factors. In addition, it was also found that bacterial inoculation significantly increased the activities of plant superoxide dismutase, catalase, peroxidase, and other defense enzymes; enhanced plant disease resistance; effectively inhibited damping-off; and promoted plant growth. In summary, the application of three rhizosphere bacteria systematically affected the interaction between plants, soil parameters, and soil microbial communities. These results provide a basis for understanding how rhizosphere bacteria promote the growth of P. sylvestris var. mongolica, thereby offering a promising sustainable alternative to chemical fertilizers.

Impact of Species-Specific Plant Growth-Promoting Rhizobacteria (PGPR) on Maize (Zea mays) Phenotypic and Biochemical Diversity

“…Singh et al (2023) showed synergistic effects of various PGPR on the growth promotion of maize. Plant biomass, root parameters and nutrient content of maize plants can be improved significantly by the inoculation of PGPR (Song et al, 2023). An increase in the contents of nutrients, specifically iron and zinc has also been reported in response to the inoculation of PGPR from Bacillus and Paenibacillus species (Ahmed et al, 2020).…”

Multifaceted Impacts of Plant-Beneficial Pseudomonas spp. in Managing Various Plant Diseases and Crop Yield Improvement

“…The most common compounds that take part in biocontrol mechanism include phenazine-1-carboxamide, lipopeptides, 2, 4-diacetylphloroglucinol (DAPG), pyrrolnitrin, pyoluteorin, and phenazine-1-carboxylic acid (PCA). 11 Pseudomonas strains survive well in stress conditions and are very beneficial in the control of several diseases triggered by fungal phytopathogens, 43 mainly damping-off disease caused by Pythium spp., 34 Fusarium solani causing okra root rot, 35 Rhizoctonia solani associated with Rhizoctonia root-rot, 36 and foliage blight disease caused by Phytophthora nicotianae. 37 Plants' ability to defend themselves is strengthened through priming as an adaptive technique.…”

“… 11 Pseudomonas strains survive well in stress conditions and are very beneficial in the control of several diseases triggered by fungal phytopathogens, 43 mainly damping-off disease caused by Pythium spp. , 34 Fusarium solani causing okra root rot, 35 Rhizoctonia solani associated with Rhizoctonia root-rot, 36 and foliage blight disease caused by Phytophthora nicotianae . 37 …”

Preparation and modification of PS–PMMA microspheres and their application in high performance liquid chromatography

“…Currently, polymeric microspheres are mainly used in high performance liquid chromatography (HPLC) as a stationary phase, and their surface is modied with certain functional groups to provide them with certain properties. The common substrates of polymer microspheres are polystyrene (PS), 1 polymethyl methacrylate (PMMA), 2 and poly(glycidyl methacrylate) (PGMA), 3,4 which are widely used in HPLC columns due to their reactivity, low cost, acid and base resistance, and biocompatibility. 5 PS microspheres have good sphericity, high specic surface area, uniform microspheres, controllable particle size, and a very active benzene ring that is reactive to a series of functional groups (e.g., -OH, -COOH, NH, -CHO, etc.).…”