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Kamal N, Liu Z, Qian C, Wu J, Zhong X. Improving hybrid Pennisetum growth and cadmium phytoremediation potential by using Bacillus megaterium BM18-2 spores as biofertilizer. Microbiol Res 2020; 242:126594. [PMID: 33007635 DOI: 10.1016/j.micres.2020.126594] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/29/2020] [Accepted: 09/11/2020] [Indexed: 10/23/2022]
Abstract
Environmental pollution with heavy metals becomes an issue of serious concern worldwide. Cadmium is considered one which adversely affects living organisms. Recently, the usage of endophytic bacteria to enhance the plant growth and phytoremediation of heavy metals contaminated sites is gaining great attention. The current study focused on utilizing the spores of Bacillus megaterium BM18-2 as biofertilizer for enhancing the growth of Cd hyperaccumulator Hybrid Pennisetum and Cd tolerance of the plant. Therefore, the production of the highest proportion of BM18-2 spores in short incubation time was investigated using different culture media. The results revealed that the maximum proportion of BM18-2 spores (90%) was obtained following incubation for 48 h in Tryptone- yeast extract media (TY). Furthermore, several growth parameters of H. Pennisetum were shown to be significantly improved by inclusion of BM18-2 spores into Cd contaminated soil in contrast to non- inoculated plant. The chlorophyll concentration of the leaves rose by 5%, 13%, and 22.89% with increasing Cd concentration of soil (20, 40 and 60 mg/Kg, respectively). The percentage of total nitrogen content of the root, stem and leaf was increased due to the bacterial spores inoculation and the highest percentage was recorded in the leaf in all treatments. Moreover, Cd phytoremediation capacity of H. Pennisetum greatly enhanced with the application of BM18-2 spores into the soil. An obvious correlation was also observed between Cd accumulation and bacterial colonization where the Cd accumulation enhanced by 21.9%, 16.5%, and 94.6% and the maximum count of BM18-2 (27 × 105, 194 × 104,and 145 × 104 CFU/g) were recorded in the root system in 20, 40, and 60 mg/Kg Cd spiked soil, respectively. Consequently, the spores of BM18-2 was proven to succeed as biofertilizer to improve growth of H. pennisetum during Cd stress which subsequently improved the phytoremediation of Cd contaminated soil.
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Affiliation(s)
- Nehal Kamal
- National Forage Breeding Innovation Base (JAAS), Nanjing, 210014, PR China; Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China; Botany and Microbiology Department, Faculty of Science, Suez University, Suez, Egypt.
| | - Zhiwei Liu
- National Forage Breeding Innovation Base (JAAS), Nanjing, 210014, PR China; Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China; Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs, Nanjing, 210014, PR China.
| | - Chen Qian
- National Forage Breeding Innovation Base (JAAS), Nanjing, 210014, PR China; Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China; Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs, Nanjing, 210014, PR China.
| | - Juanzi Wu
- National Forage Breeding Innovation Base (JAAS), Nanjing, 210014, PR China; Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China; Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs, Nanjing, 210014, PR China.
| | - Xiaoxian Zhong
- National Forage Breeding Innovation Base (JAAS), Nanjing, 210014, PR China; Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, PR China; Key Laboratory for Crop and Animal Integrated Farming of Ministry of Agriculture and Rural Affairs, Nanjing, 210014, PR China.
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Ren XM, Guo SJ, Tian W, Chen Y, Han H, Chen E, Li BL, Li YY, Chen ZJ. Effects of Plant Growth-Promoting Bacteria (PGPB) Inoculation on the Growth, Antioxidant Activity, Cu Uptake, and Bacterial Community Structure of Rape ( Brassica napus L.) Grown in Cu-Contaminated Agricultural Soil. Front Microbiol 2019; 10:1455. [PMID: 31316489 PMCID: PMC6610483 DOI: 10.3389/fmicb.2019.01455] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/11/2019] [Indexed: 11/13/2022] Open
Abstract
Previous analyses of plant growth-promoting bacteria (PGPB) combined with the remediation of heavy metal pollution in soil have largely been performed under potting or greenhouse conditions, and in situ remediation experiments under field conditions have rarely been reported. In this study, the effects of the metal-resistant PGPB Microbacterium oxydans JYC17, Pseudomonas thivervalensis Y1-3-9, and Burkholderia cepacia J62 on soil Cu pollution under rape remediation were studied in the farmland surrounding the Nanjing Jiuhuashan copper mining region in China. Following inoculation treatment for 50 days, the biomasses of the rape inoculated with strains JYC17, Y1-3-9, and J62 increased, and the total amounts of Cu uptake increased by 113.38, 66.26, and 67.91%, respectively, the translocation factor (TF) of rape inoculated with J62 was 0.85, a significant increase of 70.68%, thus improving the Cu remediation efficiency of the rape. Y1-3-9 and J62 affected the bioavailability of Cu in the soil, and the water-soluble Cu contents were increased by 10.13 and 41.77%, respectively, compared with the control. The antioxidant activities in the rape leaves showed that the tested bacteria increased the contents of antioxidant non-enzymatic substances, including ascorbic acid (ASA) and glutathione (GSH), which were increased by 40.24-91.22% and 9.89-17.67%, respectively, thereby reducing the oxidative stress caused by heavy metals and the contents of thiobarbituric acid-reactive substances (TBARS) and peroxidase (POD). PCR-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the effects of the tested bacteria on the cultivation-dependent and cultivation-independent bacterial communities in the root endosphere and rhizosphere soil of the rape. The sequencing results of the DGGE bands indicated that the tested bacteria colonized the endosphere and rhizosphere, and they became an important component of the cultivation-dependent bacteria. The canonical correspondence analysis (CCA) of the DGGE profile and similarity cluster analysis showed that the tested bacteria affected the cultivation-dependent and cultivation-independent bacterial communities in the root endosphere and rhizosphere. In this experiment, the effects and mechanisms of the combined plant-microbe remediation under field conditions were preliminarily studied, and the results are expected to provide a theoretical basis for future combined remediation experiments.
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Affiliation(s)
- Xue-Min Ren
- Innovation Center of Water Security for Water Source Region of Mid-Route Project of South-North Water Diversion of Henan Province, School of Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - Shi-Jun Guo
- School of Life Sciences and Technology, Nanyang Normal University, Nanyang, China
| | - Wei Tian
- Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, China
| | - Yan Chen
- School of Life Sciences and Technology, Nanyang Normal University, Nanyang, China
| | - Hui Han
- Innovation Center of Water Security for Water Source Region of Mid-Route Project of South-North Water Diversion of Henan Province, School of Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - E. Chen
- Gansu Province Environmental Monitoring Centre, Lanzhou, China
| | - Bai-Lian Li
- Innovation Center of Water Security for Water Source Region of Mid-Route Project of South-North Water Diversion of Henan Province, School of Agricultural Engineering, Nanyang Normal University, Nanyang, China
- Ecological Complexity and Modelling Laboratory, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, United States
| | - Yu-Ying Li
- Innovation Center of Water Security for Water Source Region of Mid-Route Project of South-North Water Diversion of Henan Province, School of Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - Zhao-Jin Chen
- Innovation Center of Water Security for Water Source Region of Mid-Route Project of South-North Water Diversion of Henan Province, School of Agricultural Engineering, Nanyang Normal University, Nanyang, China
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