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Shao L, Shen Z, Li M, Guan C, Fan B, Chai Y, Zhao Y. ccdC Regulates Biofilm Dispersal in Bacillus velezensis FZB42. Int J Mol Sci 2024; 25:5201. [PMID: 38791239 PMCID: PMC11120784 DOI: 10.3390/ijms25105201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Bacillus velezensis FZB42 is a plant growth-promoting rhizobacterium (PGPR) and a model microorganism for biofilm studies. Biofilms are required for the colonization and promotion of plant growth in the rhizosphere. However, little is known about how the final stage of the biofilm life cycle is regulated, when cells regain their motility and escape the mature biofilm to spread and colonize new niches. In this study, the non-annotated gene ccdC was found to be involved in the process of biofilm dispersion. We found that the ccdC-deficient strain maintained a wrinkled state at the late stage of biofilm formation in the liquid-gas interface culture, and the bottom solution showed a clear state, indicating that no bacterial cells actively escaped, which was further evidenced by the formation of a cellular ring (biofilm pellicle) located on top of the preformed biofilm. It can be concluded that dispersal, a biofilm property that relies on motility proficiency, is also positively affected by the unannotated gene ccdC. Furthermore, we found that the level of cyclic diguanylate (c-di-GMP) in the ccdC-deficient strain was significantly greater than that in the wild-type strain, suggesting that B. velezensis exhibits a similar mechanism by regulating the level of c-di-GMP, the master regulator of biofilm formation, dispersal, and cell motility, which controls the fitness of biofilms in Pseudomonas aeruginosain. In this study, we investigated the mechanism regulating biofilm dispersion in PGPR.
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Affiliation(s)
- Lin Shao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry and Grass, Nanjing Forestry University, Nanjing 210037, China
- College of Life Science, Nanjing Forestry University, Nanjing 210037, China
| | - Zizhu Shen
- College of Life Science, Nanjing Forestry University, Nanjing 210037, China
| | - Meiju Li
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry and Grass, Nanjing Forestry University, Nanjing 210037, China
| | - Chenyun Guan
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry and Grass, Nanjing Forestry University, Nanjing 210037, China
| | - Ben Fan
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry and Grass, Nanjing Forestry University, Nanjing 210037, China
- College of Life Science, Nanjing Forestry University, Nanjing 210037, China
| | - Yunrong Chai
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Yinjuan Zhao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry and Grass, Nanjing Forestry University, Nanjing 210037, China
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Li J, Yang C, Jousset A, Yang K, Wang X, Xu Z, Yang T, Mei X, Zhong Z, Xu Y, Shen Q, Friman VP, Wei Z. Engineering multifunctional rhizosphere probiotics using consortia of Bacillus amyloliquefaciens transposon insertion mutants. eLife 2023; 12:e90726. [PMID: 37706503 PMCID: PMC10519709 DOI: 10.7554/elife.90726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/13/2023] [Indexed: 09/15/2023] Open
Abstract
While bacterial diversity is beneficial for the functioning of rhizosphere microbiomes, multi-species bioinoculants often fail to promote plant growth. One potential reason for this is that competition between different species of inoculated consortia members creates conflicts for their survival and functioning. To circumvent this, we used transposon insertion mutagenesis to increase the functional diversity within Bacillus amyloliquefaciens bacterial species and tested if we could improve plant growth promotion by assembling consortia of highly clonal but phenotypically dissimilar mutants. While most insertion mutations were harmful, some significantly improved B. amyloliquefaciens plant growth promotion traits relative to the wild-type strain. Eight phenotypically distinct mutants were selected to test if their functioning could be improved by applying them as multifunctional consortia. We found that B. amyloliquefaciens consortium richness correlated positively with plant root colonization and protection from Ralstonia solanacearum phytopathogenic bacterium. Crucially, 8-mutant consortium consisting of phenotypically dissimilar mutants performed better than randomly assembled 8-mutant consortia, suggesting that improvements were likely driven by consortia multifunctionality instead of consortia richness. Together, our results suggest that increasing intra-species phenotypic diversity could be an effective way to improve probiotic consortium functioning and plant growth promotion in agricultural systems.
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Affiliation(s)
- Jingxuan Li
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Chunlan Yang
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Alexandre Jousset
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Keming Yang
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Xiaofang Wang
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Zhihui Xu
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Tianjie Yang
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Xinlan Mei
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Zengtao Zhong
- College of Life Science, Nanjing Agricultural UniversityNanjingChina
| | - Yangchun Xu
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Qirong Shen
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
| | - Ville-Petri Friman
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
- Department of Microbiology, University of HelsinkiHelsinkiFinland
| | - Zhong Wei
- Key Lab of Organic-based Fertilizers of China and Jiangsu Provincial Key Lab for Solid Organic Waste Utilization, Nanjing Agricultural UniversityNanjingChina
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Liu L, Ji Z, Zhao K, Zhao Y, Zhang Y, Huang S. Validation of housekeeping genes as internal controls for gene expression studies on biofilm formation in Bacillus velezensis. Appl Microbiol Biotechnol 2022; 106:2079-2089. [PMID: 35171340 DOI: 10.1007/s00253-022-11831-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/19/2022] [Accepted: 02/10/2022] [Indexed: 11/02/2022]
Abstract
Bacillus velezensis is an important bacterium widely applied in agriculture and industry, and biofilms play critical roles in its environmental tolerance. The appropriate choice of reference genes is essential for key gene expression studies. Multiple internal control genes were selected and validated from the 21 housekeeping genes of B. velezensis by expression stability evaluation during biofilm formation and were used to study the expression of key genes involved in the process. The results showed that pyk, gyrA, recA, and gyrB were stably expressed, and the expression of pyk was the most stable during biofilm formation. A pair of two genes, pyk and gyrA, provided high-quality data when used as internal controls, and the combination of three genes, pyk, gyrA, and recA, was even better. The expression levels of pyk, gyrA, and recA approximated those of five key genes, abrB, epsD, kinC, sinR, and tasA, in biofilm formation, meeting the requirements of ideal internal control genes. The expression patterns of 5 key genes were studied with 16S, pyk, the pair of 2 genes, pyk and gyrA, and the combination of 3 genes, pyk, gyrA, and recA, as internal controls during the biofilm formation process. The results proved that pyk was a suitable internal control, as were the pair of 2 genes, pyk and gyrA, and the combination of 3 genes, pyk, gyrA, and recA. This study provided genes and gene combinations which were validated as suitable internal controls for gene expression studies, especially those on the mechanism of biofilm formation in B. velezensis or even other Bacillus spp. KEY POINTS: • Reference genes is necessary for gene expression study in biofilm formation of Bacillus velezensis • Pyk and 2 gene combinations were selected and validated from 21 common used genes • Expression of key genes in biofilm formation was normalized with the selected internal controls.
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Affiliation(s)
- Lianmeng Liu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, 311400, Hangzhou, China.
| | - Zhiming Ji
- College of Biological and Food Engineering, Huaihua University, Huaihua, 418000, China
| | - Kehan Zhao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, 311400, Hangzhou, China
| | - Yuan Zhao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, 311400, Hangzhou, China
| | - Yilin Zhang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, 311400, Hangzhou, China
| | - Shiwen Huang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, 311400, Hangzhou, China. .,College of Agriculture, Guangxi University, 530003, Nanning, China.
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Zhang Y, Qi J, Wang Y, Wen J, Zhao X, Qi G. Comparative study of the role of surfactin-triggered signalling in biofilm formation among different Bacillus species. Microbiol Res 2021; 254:126920. [PMID: 34800863 DOI: 10.1016/j.micres.2021.126920] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 08/18/2021] [Accepted: 09/13/2021] [Indexed: 01/12/2023]
Abstract
The signal molecule surfactin in biofilm formation has been extensively studied in B. subtilis, but there is rare reports in other Bacillus species. In this study, we compared the surfactin-Spo0A-SinI-SinR/SlrR signalling in regulating biofilm formation amongst four Bacillus species including B. subtilis, B. amyloliquefaciens, B. velezensis, and B. licheniformis. The role of surfactin in biofilm formation was dependent on Bacillus species and strains, and the importance of surfactin was as following: B. velezensis R9 = B. amyloliquefaciens WH1 > B. licheniformis 285-3 > B. subtilis CYY. The global regulator Spo0A was essential and very conservative for biofilm formation in all four Bacillus species. The regulators SinI and SinR played different roles to regulate biofilm formation in different Bacillus species. SinI had no obvious roles in B. velezensis, B. amyloliquefaciens and B. subtilis but had a positive role in B. licheniformis. SinR had no obvious roles in B. subtilis, but played a positive role in B. velezensis, B. amyloliquefaciens and B. licheniformis. The regulator SlrR played a positive role in the biofilm formation of all four Bacillus species. Collectively, surfactin, Spo0A and SlrR are essential for the biofilm formation in all four Bacillus species, and SinR and SinI plays different roles in different Bacillus species.
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Affiliation(s)
- Yan Zhang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jishuai Qi
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuqing Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jiahong Wen
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiuyun Zhao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Gaofu Qi
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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Hutchings C, Rajasekharan SK, Reifen R, Shemesh M. Mitigating Milk-Associated Bacteria through Inducing Zinc Ions Antibiofilm Activity. Foods 2020; 9:foods9081094. [PMID: 32796547 PMCID: PMC7466369 DOI: 10.3390/foods9081094] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/01/2020] [Accepted: 08/06/2020] [Indexed: 12/27/2022] Open
Abstract
Dairy products are a sector heavily impacted by food loss, often due to bacterial contaminations. A major source of contamination is associated with the formation of biofilms by bacterial species adopted to proliferate in milk production environment and onto the surfaces of milk processing equipment. Bacterial cells within the biofilm are characterized by increased resistance to unfavorable environmental conditions and antimicrobial agents. Members of the Bacillus genus are the most commonly found spoilage microorganisms in the dairy environment. It appears that physiological behavior of these species is somehow depended on the availability of bivalent cations in the environment. One of the important cations that may affect the bacterial physiology as well as survivability are Zn2+ ions. Thus, the aim of this study was to examine the antimicrobial effect of Zn2+ ions, intending to elucidate the potential of a zinc-based antibacterial treatment suitable for the dairy industry. The antimicrobial effect of different doses of ZnCl2 was assessed microscopically. In addition, expression of biofilm related genes was evaluated using RT-PCR. Analysis of survival rates following heat treatment was conducted in order to exemplify a possible applicative use of Zn2+ ions. Addition of zinc efficiently inhibited biofilm formation by B. subtilis and further disrupted the biofilm bundles. Expression of matrix related genes was found to be notably downregulated. Microscopic evaluation showed that cell elongation was withheld when cells were grown in the presence of zinc. Finally, B. cereus and B. subtilis cells were more susceptible to heat treatment after being exposed to Zn2+ ions. It is believed that an anti-biofilm activity, expressed in downregulation of genes involved in construction of the extracellular matrix, would account for the higher sensitivity of bacteria during heat pasteurization. Consequently, we suggest that Zn2+ ions can be of used as an effective antimicrobial treatment in various applications in the dairy industry, targeting both biofilms and vegetative bacterial cells.
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Affiliation(s)
- Carmel Hutchings
- Department of Food Science, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel; (C.H.); (S.K.R.)
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 7610001, Israel;
| | - Satish Kumar Rajasekharan
- Department of Food Science, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel; (C.H.); (S.K.R.)
| | - Ram Reifen
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science and Nutrition, The Hebrew University of Jerusalem, Rehovot 7610001, Israel;
| | - Moshe Shemesh
- Department of Food Science, Institute for Postharvest Technology and Food Sciences, Agricultural Research Organization (ARO), Volcani Center, Rishon LeZion 7505101, Israel; (C.H.); (S.K.R.)
- Correspondence: ; Tel.: +972-3-968-3868
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