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Bai N, Zhang H, He Y, Zhang J, Zheng X, Zhang H, Zhang Y, Lv W, Li S. Effects of Bacillus subtilis A-5 and its fermented γ-polyglutamic acid on the rhizosphere bacterial community of Chinese cabbage. Front Microbiol 2022; 13:954489. [PMID: 36046026 PMCID: PMC9421268 DOI: 10.3389/fmicb.2022.954489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/22/2022] [Indexed: 12/01/2022] Open
Abstract
Chemical fertilizer reduction combined with novel and green agricultural inputs has become an important practice to improve microecological health in agricultural production. Given the close linkages between rhizosphere processes and plant nutrition and productivity, understanding how fertilization impacts this critical zone is highly important for optimizing plant–soil interactions and crop fitness for agricultural sustainability. Here, by using a pot experimental system, we demonstrated that nitrogen fertilizer reduction and microbial agent application promoted plant fitness and altered the microbial community structure in the rhizosphere soil with the following treatments: no fertilization, CK; conventional chemical fertilizer, CF; 30% reduced nitrogen fertilizer, N; 30% reduced nitrogen fertilizer with pure γ-PGA, PGA; 30% reduced nitrogen fertilizer with Bacillus subtilis A-5, A5; 30% reduced nitrogen fertilizer with γ-PGA fermentation broth, FJY. The PGA, A5, and FJY treatments all significantly promoted crop growth, and the FJY treatment showed the strongest positive effect on Chinese cabbage yield (26,385.09 kg/hm2) (P < 0.05). Microbial agents affected the α diversity of the rhizosphere bacterial community; the addition of B. subtilis A-5 (A5 and FJY treatments) significantly affected rhizospheric bacterial community structure. Urease activity and soil pH were the key factors affecting bacterial community structure and composition. The FJY treatment seemed to influence the relative abundances of important bacterial taxa related to metabolite degradation, predation, and nitrogen cycling. This discovery provides insight into the mechanism underlying the effects of microbial agent inputs on rhizosphere microbial community assembly and highlights a promising direction for the manipulation of the rhizosphere microbiome to yield beneficial outcomes.
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Affiliation(s)
- Naling Bai
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Hanlin Zhang
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Yu He
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Juanqin Zhang
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Agricultural Environment and Farmland Conservation Experiment Station of Ministry Agriculture and Rural Affairs, Shanghai, China
| | - Xianqing Zheng
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Agricultural Environment and Farmland Conservation Experiment Station of Ministry Agriculture and Rural Affairs, Shanghai, China
| | - Haiyun Zhang
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Shanghai Key Laboratory of Horticultural Technology, Shanghai, China
| | - Yue Zhang
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Shanghai Key Laboratory of Horticultural Technology, Shanghai, China
| | - Weiguang Lv
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Agricultural Environment and Farmland Conservation Experiment Station of Ministry Agriculture and Rural Affairs, Shanghai, China
- Shanghai Key Laboratory of Horticultural Technology, Shanghai, China
- Key Laboratory of Low-carbon Green Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China
- *Correspondence: Weiguang Lv
| | - Shuangxi Li
- Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China
- Agricultural Environment and Farmland Conservation Experiment Station of Ministry Agriculture and Rural Affairs, Shanghai, China
- Shanghai Key Laboratory of Horticultural Technology, Shanghai, China
- Key Laboratory of Low-carbon Green Agriculture, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shuangxi Li
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Yurgel SN, Ajeethan N, Smertenko A. Response of Plant-Associated Microbiome to Plant Root Colonization by Exogenous Bacterial Endophyte in Perennial Crops. Front Microbiol 2022; 13:863946. [PMID: 35479645 PMCID: PMC9037143 DOI: 10.3389/fmicb.2022.863946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
The application of bacterial inoculums for improving plant growth and production is an important component of sustainable agriculture. However, the efficiency of perennial crop inoculums depends on the ability of the introduced endophytes to exert an impact on the host-plant over an extended period of time. This impact might be evaluated by the response of plant-associated microbiome to the inoculation. In this study, we monitored the effect of a single bacterial strain inoculation on the diversity, structure, and cooperation in plant-associated microbiome over 1-year period. An endophyte (RF67) isolated from Vaccinium angustifolium (wild blueberry) roots and annotated as Rhizobium was used for the inoculation of 1-year-old Lonicera caerulea (Haskap) plants. A significant level of bacterial community perturbation was detected in plant roots after 3 months post-inoculation. About 23% of root-associated community variation was correlated with an application of the inoculant, which was accompanied by increased cooperation between taxa belonging to Proteobacteria and Actinobacteriota phyla and decreased cooperation between Firmicutes in plant roots. Additionally, a decrease in bacterial Shannon diversity and an increase in the relative abundances of Rhizobiaceae and Enterobacteriaceae were detected in the roots of inoculated plants relative to the non-inoculated control. A strong effect of the inoculation on the bacterial cooperation was also detected after 1 year of plant field growth, whereas no differences in bacterial community composition and also alpha and beta diversities were detected between bacterial communities from inoculated and non-inoculated roots. These findings suggest that while exogenous endophytes might have a short-term effect on the root microbiome structure and composition, they can boost cooperation between plant-growth-promoting endophytes, which can exist for the extended period of time providing the host-plant with long-lasting beneficial effects.
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Affiliation(s)
- Svetlana N. Yurgel
- Grain Legume Genetics and Physiology Research Unit, U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), Prosser, WA, United States
| | - Nivethika Ajeethan
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada
- Department of Biosystems Technology, Faculty of Technology, University of Jaffna, Kilinochchi, Sri Lanka
| | - Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
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