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Li X, Ding Y, Okoye CO, Geng X, Jiang H, Wang Y, Wu Y, Gao L, Fu L, Jiang J, Sun J. Performance of Halo-Alkali-Tolerant Endophytic Bacteria on Hybrid Pennisetum and Bacterial Community under Varying Soil Conditions. Microorganisms 2024; 12:1062. [PMID: 38930444 PMCID: PMC11205500 DOI: 10.3390/microorganisms12061062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/21/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024] Open
Abstract
Halo-alkali soil threatens agriculture, reducing growth and crop yield worldwide. In this study, physicochemical and molecular techniques were employed to explore the potential of halo-alkali-tolerant endophytic bacteria strains Sphingomonas sp. pp01, Bacillus sp. pp02, Pantoea sp. pp04, and Enterobacter sp. pp06 to enhance the growth of hybrid Pennisetum under varying saline conditions. The strains exhibited tolerance to high salt concentrations, alkaline pH, and high temperatures. Under controlled conditions, all four strains showed significant growth-promoting effects on hybrid Pennisetum inoculated individually or in combination. However, the effects were significantly reduced in coastal saline soil. The best growth-promoting effect was achieved under greenhouse conditions, increasing shoot fresh and dry weights of hybrid Pennisetum by up to 457.7% and 374.7%, respectively, using irrigating trials. Metagenomic sequencing analysis revealed that the diversity and composition of rhizosphere microbiota underwent significant changes after inoculation with endophytic bacteria. Specifically, pp02 and co-inoculation significantly increased the Dyella and Pseudomonas population. Firmicutes, Mycobacteria, and Proteobacteria phyla were enriched in Bacillus PP02 samples. These may explain the best growth-promoting effects of pp02 and co-inoculation on hybrid Pennisetum under greenhouse conditions. Our findings reveal the performance of endophytic bacterial inoculants in enhancing beneficial microbiota, salt stress tolerance, and hybrid Pennisetum growth.
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Affiliation(s)
- Xia Li
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Yiming Ding
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Charles Obinwanne Okoye
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China
- Department of Zoology & Environmental Biology, University of Nigeria, Nsukka 410001, Nigeria
| | - Xiaoyan Geng
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
- Library, Jiangsu University, Zhenjiang 212013, China
| | - Huifang Jiang
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Yongli Wang
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Yanfang Wu
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Lu Gao
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Lei Fu
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Jianxiong Jiang
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
| | - Jianzhong Sun
- Biofuels Institute, School of Emergency Management, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; (Y.D.); (C.O.O.); (X.G.); (H.J.); (Y.W.); (Y.W.); (L.G.); (L.F.); (J.J.)
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Use of Biostimulants as a New Approach for the Improvement of Phytoremediation Performance—A Review. PLANTS 2022; 11:plants11151946. [PMID: 35893650 PMCID: PMC9332818 DOI: 10.3390/plants11151946] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/16/2022] [Accepted: 07/20/2022] [Indexed: 11/23/2022]
Abstract
Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. Bioremediation techniques, on the other hand, represent a promising alternative. Among them, phytoremediation is attracting particular attention, a green methodology that relies on the use of plant species to remediate contaminated sites or prevent the dispersion of xenobiotics into the environment. In this review, after a brief introduction focused on pollution and phytoremediation, the use of plant biostimulants (PBs) in the improvement of the remediation effectiveness is proposed. PBs are substances widely used in agriculture to raise crop production and resistance to various types of stress. Recent studies have also documented their ability to counteract the deleterious effects of pollutants on plants, thus increasing the phytoremediation efficiency of some species. The works published to date, reviewed and discussed in the present work, reveal promising prospects in the remediation of polluted environments, especially for heavy metals, when PBs derived from humic substances, protein and amino acid hydrolysate, inorganic salts, microbes, seaweed, plant extracts, and fungi are employed.
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Gluconacetobacter diazotrophicus Inoculation of Two Lettuce Cultivars Affects Leaf and Root Growth under Hydroponic Conditions. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The growth-promoting effects of Gluconacetobacter diazotrophicus inoculation on the leaf lettuce (Lactuca sativa L.) cultivars “Black Seeded Simpson” and “Bibb/Limestone” were investigated. Plants of each cultivar were grown hydroponically in Kratky jars in a growth chamber-controlled environment in a completely randomized factorial design with three or four replications. Each experiment was repeated once. Factors were (1) with or without inoculant and (2) seven levels of nitrogen (N) fertilization ranging from deficient (37.5 mg L−1 N) to excessive (172.5 mg L−1 N). The shoot, root, and total biomass accumulation, nitrogen density, and carbon/nitrogen (C/N) ratios were measured for each variety. Black Seeded Simpson demonstrated a shifting of production towards aerial tissues, with significantly greater shoot production and reduced root production. The observed increase in shoot biomass was greatest at the slightly deficient N rate of 105 mg L−1 N where inoculated plants produced 14.8% more than uninoculated plants. Lower N density and higher C/N ratios in inoculated shoot tissues indicate greater N use efficiency. Bibb/Limestone responded to inoculation with an average increase of 10.9% in shoot production and with greater root biomass. Bibb/Limestone also exhibited lower N density in inoculated shoot tissues with a corresponding increase in the C/N ratio. For growers looking to maximize lettuce yields, G. diaz inoculation may present a beneficial additive to the growing system by increasing leaf yields while not increasing N fertilizer requirements.
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Pellegrini M, Ercole C, Gianchino C, Bernardi M, Pace L, Del Gallo M. Fusarium Oxysporum f. sp. Cannabis Isolated from Cannabis Sativa L.: In Vitro and In Planta Biocontrol by a Plant Growth Promoting-Bacteria Consortium. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112436. [PMID: 34834799 PMCID: PMC8623994 DOI: 10.3390/plants10112436] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Industrial hemp (Cannabis sativa L.) is a multipurpose plant used in several fields. Several phytopathogens attack hemp crops. Fusarium oxysporum is a common fungal pathogen that causes wilt disease in nurseries and in field cultivation and causes high losses. In the present study, a pathogenic strain belonging to F. oxysporum f. sp. cannabis was isolated from a plant showing Fusarium wilt. After isolation, identification was conducted based on morphological and molecular characterizations and pathogenicity tests. Selected plant growth-promoting bacteria with interesting biocontrol properties-Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae and Burkholderia ambifaria-were tested against this pathogen. In vitro antagonistic activity was determined by the dual culture method. Effective strains (in vitro inhibition > of 50%) G. diazotrophicus, H. seropedicae and B. ambifaria were combined in a consortium and screened for in planta antagonistic activity in pre-emergence (before germination) and post-emergence (after germination). The consortium counteracted Fusarium infection both in pre-emergence and post-emergence. Our preliminary results show that the selected consortium could be further investigated as an effective biocontrol agent for the management of this pathogen.
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