The utilization of plant growth-promoting rhizobacteria (PGPR) holds great promise for the restoration of damaged terrestrial plant ecosystems. However, there is a significant knowledge gap regarding the application of PGPR in rehabilitating aquatic ecosystems. In this study, we conducted a mesocosm experiment to investigate the effects of Raoultella ornithinolytica F65, Pantoea cypripedii G84, Klebsiella variicola G85, Novosphingobium profundi G86, and Klebsiella pneumoniae I109 on eelgrass ( Zostera marina L.), which is a crucial marine angiosperm. The application of these strains resulted in a significant increase in the new leaf area of eelgrass, with improvements of 55.4%, 14.4%, 39.1%, 20.6%, and 55.7% observed, respectively. Moreover, PGPR inoculation enhanced shoot biomass, rhizome elongation, leaf carbon and nitrogen content, as well as photosynthetic pigments. Furthermore, it stimulated enzymatic activities within the rhizosphere soil and positively influenced its physicochemical properties. The Illumina Miseq sequencing results revealed a positive shift in the bacterial community, leading to an enrichment of functional groups associated with nitrogen fixation and degradation of aromatic compounds. These findings underscore the significant potential of PGPR as a transformative tool for enhancing seagrass growth and survival, offering innovative strategies for the restoration of degraded seagrass meadows. This research not only advances our understanding of microbial-plant interactions in aquatic ecosystems but contributes to the broader goals of ecosystem revitalization and biodiversity conservation.

The ginseng industry's reliance on chemicals for fertilizer and pesticides has adversely affected the environment and decreased the quality of ginseng; therefore, microbial inoculum is an effective way to restore the damaged soil in ginseng fields. To investigate the effects of plant growth-promoting rhizobacteria (PGPR) and spent mushroom substrate (SMS) on soil and plant quality in ginseng, high throughput sequencing was performed to examine the microbial community structures in ginseng rhizosphere soil. All treatments significantly increased soil nutrient, enzyme activity, and ginseng biomass compared to control (p < 0.05). The combination of PGPR and SMS notably enhanced soil enzyme activities: urease (7.29%), sucrase (29.76%), acid phosphatase (13.24%), and amylase (38.25%) (p < 0.05). All treatments had different effects on ginseng rhizosphere soil microbial diversity. Significantly, the combination treatments enhanced microbial diversity by increasing the abundance of beneficial bacteria such as Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Plectosphaerella, meanwhile suppressing harmful Klebsiella. The relative abundance of Fusarium was reduced to some extent compared with the application of SMS alone. The soil organic matter, available potassium, available phosphorus, and alkaline nitrogen, as key factors, influenced microbial community structures. Overall, the combination of PGPR and SMS positively impacted the rhizosphere environment and ginseng plant quality.

Drought is one of the main devastating environmental factors limiting crops' development and productivity. This study investigated the role of combining intercropping and co-inoculation of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) to protect barley and alfalfa against drought damage. The experiment design consisted of four inoculation treatments: (1) non-inoculated plants (C), (2) plants inoculated with AMF consortium (AMF), (3) plants inoculated with the bacterial consortium (PGPR), and (4) plants co-inoculated with AMF + PGPR (AMF + PGPR), and two irrigation regimes: (i) well-watered, equivalent to 75% field capacity (FC), and (ii) drought, where watering was maintained at 35% FC. For each treatment (inoculated or not inoculated and stressed or not stressed), the plants of barley and alfalfa were monocropped and intercropped. Growth (shoots and roots dry weight), physiological (stomatal conductance and chlorophyll fluorescence), and biochemical (stress markers, osmolytes contents, and antioxidant enzyme activities) parameters were all measured. The results showed that applying intercropping and microbial inoculation AMF or/and PGPR enhanced the tolerance of plants to drought stress. The most pronounced effect was displayed by combining intercropping system and co-inoculation of AMF + PGPR, which improved shoot and root dry weight by 141 and 280% in barley and by 512 and 533% in alfalfa, respectively, compared to their respective uninoculated monocultures. Similarly, combining intercropping and co-inoculation with AMF + PGPR enhanced acid phosphatase, superoxide dismutase, and catalase activities by 125%, 161%, and 58% in barley and by 114%, 311%, and 112% in alfalfa, respectively, compared to their respective uninoculated monocultures. Furthermore, the thousand-seed weight was increased by 73% in barley intercropped and inoculated with AMF +PGPR. These findings revealed that intercropping barley and alfalfa and co-inoculation of AMF +PGPR may provide a sustainable approach to enhance drought tolerance, increase crop productivity, and promote food security.