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Al-Saadi HA, Al-Sadi AM, Al-Wahaibi A, Al-Raeesi A, Al-Kindi M, Soundra Pandian SB, Al-Harrasi MMA, Al-Mahmooli IH, Velazhahan R. Rice Weevil ( Sitophilus oryzae L.) Gut Bacteria Inhibit Growth of Aspergillus flavus and Degrade Aflatoxin B1. J Fungi (Basel) 2024; 10:377. [PMID: 38921363 PMCID: PMC11205148 DOI: 10.3390/jof10060377] [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: 04/18/2024] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 06/27/2024] Open
Abstract
In this study, bacteria residing in the gut of the rice weevils (Sitophilus oryzae L.) (Coleoptera: Curculionidae) feeding on aflatoxin-contaminated corn kernels were isolated and evaluated for their ability to suppress Aspergillus flavus and to remove/degrade aflatoxin B1 (AFB1). Four morphologically distinct S. oryzae gut-associated bacterial isolates were isolated and identified as Bacillus subtilis (RWGB1), Bacillus oceanisediminis (RWGB2), Bacillus firmus (RWGB3), and Pseudomonas aeruginosa (RWGB4) based on 16S rRNA gene sequence analysis. These bacterial isolates inhibited A. flavus growth in the dual culture assay and induced morphological deformities in the fungal hyphae, as confirmed by scanning electron microscopy. All four bacterial isolates were capable of removing AFB1 from the nutrient broth medium. In addition, culture supernatants of these bacterial isolates degraded AFB1, and the degradation of toxin molecules was confirmed by liquid chromatography-mass spectrometry. The bacterial isolates, B. subtilis RWGB1, B. oceanisediminis RWGB2, and P. aeruginosa RWGB4, were capable of producing antifungal volatile organic compounds that inhibited A. flavus growth. These results suggest that the bacterial isolates from S. oryzae gut have the potential to bind and/or degrade AFB1. Further research on their application in the food and feed industries could enhance the safety of food and feed production.
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Affiliation(s)
- Haneen Abdullah Al-Saadi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Abdullah Mohammed Al-Sadi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Ali Al-Wahaibi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Ali Al-Raeesi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Mohamed Al-Kindi
- College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman;
| | | | - Majida Mohammed Ali Al-Harrasi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Issa Hashil Al-Mahmooli
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
| | - Rethinasamy Velazhahan
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman; (H.A.A.-S.); (A.M.A.-S.); (A.A.-W.); (A.A.-R.); (M.M.A.A.-H.); (I.H.A.-M.)
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Zhu XC, Xu SG, Wang YR, Zou MT, Mridha MAU, Javed K, Wang Y. Unveiling the Potential of Bacillus safensis Y246 for Enhanced Suppression of Rhizoctonia solani. J Fungi (Basel) 2023; 9:1085. [PMID: 37998890 PMCID: PMC10672523 DOI: 10.3390/jof9111085] [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: 09/22/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/25/2023] Open
Abstract
Rhizoctonia solani is a significant pathogen affecting various crops, including tobacco. In this study, a bacterial strain, namely Y246, was isolated from the soil of healthy plants and exhibited high antifungal activity. Based on morphological identification and DNA sequencing, this bacterial strain was identified as Bacillus safensis. The aim of this investigation was to explore the antifungal potential of strain Y246, to test the antifungal stability of Y246 by adjusting different cultivation conditions, and to utilize gas chromatography-mass spectrometry (GC-MS) to predict the volatile compounds related to antifungal activity in Y246. In vitro assays demonstrated that strain Y246 exhibited a high fungal inhibition rate of 76.3%. The fermentation broth and suspension of strain Y246 inhibited the mycelial growth of R. solani by 66.59% and 63.75%, respectively. Interestingly, treatment with volatile compounds derived from the fermentation broth of strain Y246 resulted in abnormal mycelial growth of R. solani. Scanning electron microscopy analysis revealed bent and deformed mycelium structures with a rough surface. Furthermore, the stability of antifungal activity of the fermentation broth of strain Y246 was assessed. Changes in temperature, pH value, and UV irradiation time had minimal impact on the antifungal activity, indicating the stability of the antifungal activity of strain Y246. A GC-MS analysis of the volatile organic compounds (VOCs) produced by strain Y246 identified a total of 34 compounds with inhibitory effects against different fungi. Notably, the strain demonstrated broad-spectrum activity, exhibiting varying degrees of inhibition against seven pathogens (Alternaria alternata, Phomopsis. sp., Gloeosporium musarum, Dwiroopa punicae, Colletotrichum karstii, Botryosphaeria auasmontanum, and Botrytis cinerea). In our extensive experiments, strain Y246 not only exhibited strong inhibition against R. solani but also demonstrated remarkable inhibitory effects on A. alternata-induced tobacco brown spot and kiwifruit black spot, with impressive inhibition rates of 62.96% and 46.23%, respectively. Overall, these findings highlight the significant antifungal activity of B. safensis Y246 against R. solani. In addition, Y246 has an excellent antifungal stability, with an inhibition rate > 30% under different treatments (temperature, pH, UV). The results showed that the VOCs of strain Y246 had a strong inhibitory effect on the colony growth of R. solani, and the volatile substances produced by strain Y246 had an inhibitory effect on R. solani at rate of 70.19%. Based on these results, we can conclude that Y246 inhibits the normal growth of R. solani. These findings can provide valuable insights for developing sustainable agricultural strategies.
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Affiliation(s)
- Xing-Cheng Zhu
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
| | - Shu-Gang Xu
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
| | - Yu-Ru Wang
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
| | - Meng-Ting Zou
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
| | | | - Khadija Javed
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
- Julius Kühn-Institut (JKI) for Biological Control, 64287 Darmstadt, Germany
| | - Yong Wang
- Department of Plant Pathology, Agriculture College, Guizhou University, Guiyang 550025, China; (X.-C.Z.); (S.-G.X.); (Y.-R.W.); (M.-T.Z.)
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Wang L, Fan R, Ma H, Sun Y, Huang Y, Wang Y, Guo Q, Ren X, Xu L, Zhao J, Zhang L, Xu Y, Jin L, Dong Y, Quan C. Genomic and metabolomic insights into the antimicrobial compounds and plant growth-promoting potential of Bacillus velezensis Q-426. BMC Genomics 2023; 24:589. [PMID: 37794314 PMCID: PMC10548584 DOI: 10.1186/s12864-023-09662-1] [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: 05/03/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND The Q-426 strain isolated from compost samples has excellent antifungal activities against a variety of plant pathogens. However, the complete genome of Q-426 is still unclear, which limits the potential application of Q-426. RESULTS Genome sequencing revealed that Q-426 contains a single circular chromosome 4,086,827 bp in length, with 4691 coding sequences and an average GC content of 46.3%. The Q-426 strain has a high degree of collinearity with B. velezensis FZB42, B. velezensis SQR9, and B. amyloliquefaciens DSM7, and the strain was reidentified as B. velezensis Q-426 based on the homology analysis results. Many genes in the Q-426 genome have plant growth-promoting activity, including the secondary metabolites of lipopeptides. Genome mining revealed 14 clusters and 732 genes encoding secondary metabolites with predicted functions, including the surfactin, iturin, and fengycin families. In addition, twelve lipopeptides (surfactin, iturin and fengycin) were successfully detected from the fermentation broth of B. velezensis Q-426 by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS), which is consistent with the genome analysis results. We found that Q-426 produced indole-3-acetic acid (IAA) at 1.56 mg/l on the third day of incubation, which might promote the growth of plants. Moreover, we identified eighteen volatile compounds (VOCs, including 2-heptanone, 6-methylheptan-2-one, 5-methylheptan-2-one, 2-nonanone, 2-decanone, 2-undecanone, 2-dodecanone, 2-tridecanone, 2-tetradecanone, 2-nonadecanone, pentadecanoic acid, oleic acid, dethyl phthalate, dibutyl phthalate, methyl (9E,12E)-octadeca-9,12-dienoate), pentadecane, (6E,10E)-1,2,3,4,4a,5,8,9,12,12a-decahydro-1,4-methanobenzo[10]annulene, and nonanal) based on gas chromatograph-mass spectrometer (GC/MS) results. CONCLUSIONS We mined secondary metabolite-related genes from the genome based on whole-genome sequence results. Our study laid the theoretical foundation for the development of secondary metabolites and the application of B. velezensis Q-426. Our findings provide insights into the genetic characteristics responsible for the bioactivities and potential application of B. velezensis Q-426 as a plant growth-promoting strain in ecological agriculture.
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Affiliation(s)
- Lulu Wang
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Ruochen Fan
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Haodi Ma
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Yu Sun
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China
| | - Yangzhu Huang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Yuxin Wang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Qinfeng Guo
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China
| | - Xinxiu Ren
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China
| | - Lukai Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Jing Zhao
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Liying Zhang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Yongbin Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Liming Jin
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China
| | - Yuesheng Dong
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian, 116024, Liaoning, China.
| | - Chunshan Quan
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China.
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian, China.
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Kaur G, Patel A, Dwibedi V, Rath SK. Harnessing the action mechanisms of microbial endophytes for enhancing plant performance and stress tolerance: current understanding and future perspectives. Arch Microbiol 2023; 205:303. [PMID: 37561224 DOI: 10.1007/s00203-023-03643-4] [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: 05/25/2023] [Revised: 07/11/2023] [Accepted: 07/28/2023] [Indexed: 08/11/2023]
Abstract
Microbial endophytes are microorganisms that reside within plant tissues without causing any harm to their hosts. These microorganisms have been found to confer a range of benefits to plants, including increased growth and stress tolerance. In this review, we summarize the recent advances in our understanding of the mechanisms by which microbial endophytes confer abiotic and biotic stress tolerance to their host plants. Specifically, we focus on the roles of endophytes in enhancing nutrient uptake, modulating plant hormones, producing secondary metabolites, and activating plant defence responses. We also discuss the challenges associated with developing microbial endophyte-based products for commercial use, including product refinement, toxicology analysis, and prototype formulation. Despite these challenges, there is growing interest in the potential applications of microbial endophytes in agriculture and environmental remediation. With further research and development, microbial endophyte-based products have the potential to play a significant role in sustainable agriculture and environmental management.
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Affiliation(s)
- Gursharan Kaur
- University Institute of Biotechnology, Chandigarh University, Mohali, 140413, India
| | - Arvind Patel
- University Institute of Biotechnology, Chandigarh University, Mohali, 140413, India
| | - Vagish Dwibedi
- University Institute of Biotechnology, Chandigarh University, Mohali, 140413, India.
- Institute of Soil, Water and Environmental Sciences, Volcani Resaerch Center, Agricultural Research Organization, 7528809, Rishon Lezion, Israel.
| | - Santosh Kumar Rath
- Department of Pharmaceutical Chemistry, School of Pharmaceuticals and Population Health Informatics, Faculty of Pharmacy, DIT University, Dehradun, 248009, Uttarakhand, India.
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Al-Rahbi BAA, Al-Sadi AM, Al-Harrasi MMA, Al-Sabahi JN, Al-Mahmooli IH, Blackburn D, Velazhahan R. Effectiveness of Endophytic and Rhizospheric Bacteria from Moringa spp. in Controlling Pythium aphanidermatum Damping-Off of Cabbage. PLANTS (BASEL, SWITZERLAND) 2023; 12:668. [PMID: 36771752 PMCID: PMC9919774 DOI: 10.3390/plants12030668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
In this study, endophytic and rhizospheric bacteria were isolated from Moringa olifera and M. perigreina from Oman, and their in vitro antagonistic activity against Pythium aphanidermatum was tested using a dual culture assay. The promising strains were tested further for their compatibility and potential for plant growth promotion, biofilm formation, antifungal volatile organic compound (VOC) production, and the biological control of P. aphanidermatum damping-off of cabbage (Brassica oleracea L.) under greenhouse conditions. A total of 12 endophytic and 27 rhizospheric bacteria were isolated from Moringa spp. Among them, Bacillus pumilus MPE1 showed the maximum antagonistic activity against P. aphanidermatum in the dual culture assay, followed by Paenibacillus glucanolyticus MPE3 and Pseudomonas indica MOR3 and MOR8. These bacterial isolates induced abundant morphological abnormalities in the hyphae of P. aphanidermatum, as observed via scanning electron microscopy. The in vitro cross-streak assay showed that these bacterial isolates were compatible among themselves, except for P. indica MOR8 × P. glucanolyticus MPE3. These antagonists released VOCs that restricted the growth of P. aphanidermatum in an in vitro assay. These antagonistic bacteria released 2,4-dimethylheptane and 4-methyloctane as the predominant volatile compounds. Of the four antagonistic bacterial strains, P. indica MOR8 was capable of forming biofilm, which is considered a trait that improves the efficacy of rhizosphere inoculants. The results of the greenhouse experiments showed that the soil treatment with B. pumilus MPE1 showed the highest reduction (59%) in the incidence of P. aphanidermatum damping-off in cabbage, evidencing its potential as a biological control agent for the management of this disease. Further research is needed to characterize the antifungal traits and activities of B. pumilus MPE1 and to assert its potential use against other soil-borne plant pathogens.
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Affiliation(s)
- Buthaina Aamir Ali Al-Rahbi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Abdullah Mohammed Al-Sadi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Majida Mohammed Ali Al-Harrasi
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Jamal Nasser Al-Sabahi
- Central Instrumentation Laboratory, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Issa Hashil Al-Mahmooli
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Daniel Blackburn
- Department of Soil, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
| | - Rethinasamy Velazhahan
- Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al-Khoud, Muscat 123, Oman
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Nzimande B, Kumalo HM, Ndlovu SI, Mkhwanazi NP. Secondary metabolites produced by endophytic fungi, Alternaria alternata, as potential inhibitors of the human immunodeficiency virus. Front Genet 2022; 13:1077159. [PMID: 36583026 PMCID: PMC9794146 DOI: 10.3389/fgene.2022.1077159] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022] Open
Abstract
Antiretroviral treatment has significantly reduced human immunodeficiency virus infection and mortality. However, the current treatment regimen is limited by adverse side effects, the emergence of drug resistance, and the inability to eliminate viral reservoirs. Here, fifteen endophytic fungi were isolated from Sclerocarya birrea and Hypoxis plants. Crude extracts of Alternaria alternata (strain ID PO4PR1, PO4PR2, and PO2PL1) of the fifteen isolate's crude extracts showed anti-HIV-1 activity in TZM-bl cell line at inhibitory concentration (IC50) values ranging from 0.017 to 1.170 μg/ml. The three crude extracts also maintained the virus replication inhibition profile on PBMCs and CD4+ T cells at concentrations ranging from 0.3 to 50.2 ng/ml. Partial purification using the solid phase extraction and analysis with Gas Chromatography-Mass spectrophotometry showed a diverse profile. The bioactive compounds were identified based on peak area, retention time, similarity index. The major compounds from GC-MS analysis of A. Alternata revealed the existence of cyclotrisiloxane octamethyl (22.92%); Propaninitrile (16,67%); Pyrrolol[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methyl propyl) (10.42%); Silane, diethylethoxy(2-ethoxyethyloxy) (4.17%); Coumarin, 3,4-dihydro-4,5,7-trimethyl- 4,5,7-Trimethyl-2-chromanone (13.7%) and 1,2-Cyclobutanedicarbonitrile (2.08%) with previously reported biological activities such as antimicrobial, anti-inflammatory and antioxidant properties. Therefore, these bioactive compounds from A. alternata fungal endophytes could be repurposed as potential anti-HIV agents. This study showed the potential of endophytic fungi, Alternaria alternata from S. birrea, and Hypoxis species as producers of anti-HIV compounds.
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Affiliation(s)
- Bruce Nzimande
- Discipline of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, Medical School, University of KwaZulu-Natal, Durban, South Africa
| | - Hezekiel M. Kumalo
- Drug Research and Innovation Unit, Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, Medical School, University of KwaZulu-Natal, Durban, South Africa
| | - Sizwe I. Ndlovu
- Discipline of Medical Microbiology, School of Laboratory Medicine and Medical Sciences, Medical School, University of KwaZulu-Natal, Durban, South Africa,Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Johannesburg, South Africa,*Correspondence: Sizwe I. Ndlovu, ; Nompumelelo P. Mkhwanazi,
| | - Nompumelelo P. Mkhwanazi
- HIV Pathogenesis Programme, Doris Duke Medical Research Institute, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa,*Correspondence: Sizwe I. Ndlovu, ; Nompumelelo P. Mkhwanazi,
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Kandasamy GD, Kathirvel P. Insights into bacterial endophytic diversity and isolation with a focus on their potential applications –A review. Microbiol Res 2022; 266:127256. [DOI: 10.1016/j.micres.2022.127256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 11/14/2022]
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8
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Aloo BN, Tripathi V, Makumba BA, Mbega ER. Plant growth-promoting rhizobacterial biofertilizers for crop production: The past, present, and future. FRONTIERS IN PLANT SCIENCE 2022; 13:1002448. [PMID: 36186083 PMCID: PMC9523260 DOI: 10.3389/fpls.2022.1002448] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Recent decades have witnessed increased agricultural production to match the global demand for food fueled by population increase. Conventional agricultural practices are heavily reliant on artificial fertilizers that have numerous human and environmental health effects. Cognizant of this, sustainability researchers and environmentalists have increased their focus on other crop fertilization mechanisms. Biofertilizers are microbial formulations constituted of indigenous plant growth-promoting rhizobacteria (PGPR) that directly or indirectly promote plant growth through the solubilization of soil nutrients, and the production of plant growth-stimulating hormones and iron-sequestering metabolites called siderophores. Biofertilizers have continually been studied, recommended, and even successfully adopted for the production of many crops in the world. These microbial products hold massive potential as sustainable crop production tools, especially in the wake of climate change that is partly fueled by artificial fertilizers. Despite the growing interest in the technology, its full potential has not yet been achieved and utilization still seems to be in infancy. There is a need to shed light on the past, current, and future prospects of biofertilizers to increase their understanding and utility. This review evaluates the history of PGPR biofertilizers, assesses their present utilization, and critically advocates their future in sustainable crop production. It, therefore, updates our understanding of the evolution of PGPR biofertilizers in crop production. Such information can facilitate the evaluation of their potential and ultimately pave the way for increased exploitation.
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Affiliation(s)
- Becky N. Aloo
- Department of Biological Sciences, University of Eldoret, Eldoret, Kenya
| | - Vishal Tripathi
- Department of Biotechnology, GLA University, Mathura, Uttar Pradesh, India
| | - Billy A. Makumba
- Department of Biological and Physical Sciences, Moi University, Eldoret, Kenya
| | - Ernest R. Mbega
- Department of Sustainable Agriculture and Biodiversity Conservation, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
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Pseudomonas spp. Mediate defense response in sugarcane through differential exudation of root phenolics. Saudi J Biol Sci 2021; 28:7528-7538. [PMID: 34867057 PMCID: PMC8626327 DOI: 10.1016/j.sjbs.2021.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/11/2021] [Accepted: 09/12/2021] [Indexed: 11/21/2022] Open
Abstract
Pseudomonas spp., a ubiquitous biocontrol agent, protects the plants from phytopathogens by suppressing them directly by reinforcing the plant’s intrinsic defense mechanism. Root exudated phenolics play an important role in establishing the rhizobacteria population and cross the host boundaries in beneficial plant–microbe interaction. In this study, Pseudomonas spp. HU-8 & HU-9 antagonized the sugarcane red rot pathogen (C. falcatum) and showed a positive chemotactic response against different concentrations (10–30 µM) of synthetic phenolic acids like p-coumaric, vanillic, and 3,4 di-hydroxybenzoic acid. In a pot experiment, they effectively colonized the sugarcane rhizosphere and mediated defense response in sugarcane plants challenged with red rot pathogen C. falcatum by regulating the exudation of root phenolics under hydroponic conditions. They significantly induced the activity of the antioxidant enzymes CAT (1.24–1.64 fold), PO (0.78–1.61 fold), PAL (0.77–0.97 fold), and PPO (3.67–3.73 fold) over untreated plants in sugarcane. They also induced the total phenolic contents (TPC) in sugarcane in the presence (6.56–10.29 mg/g GAE) and absence (2.89–4.16 mg/g GAE) of the pathogen quantified through the Folin-Ciocalteu (FC) method. However, their effect was lower than that of the pathogen (4.34–8 mg/g GAE). The Pseudomonas spp. significantly colonized the sugarcane rhizosphere by maintaining a cell population of (1.0E + 07–1.3E + 08 CFU/mL). A significant positive Pearson’s correlation was observed between the root exudated total phenolic contents, antioxidant enzymatic activities, and rhizospheric population of inoculated bacteria. The 16S rRNA and rpoD gene analysis showed sequence conservation (C: 0.707), average number of nucleotide differences (k: 199.816), nucleotide diversity, (Pi): 0.09819), average number of informative nucleotide sites per site (Psi: 0.01275), GC content (0.57), and polymorphic sites (n = 656). These diverse Pseudomonas spp. could be an ideal bio-inoculants for a broad range of hosts especially graminaceous crops.
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Lammers A, Zweers H, Sandfeld T, Bilde T, Garbeva P, Schramm A, Lalk M. Antimicrobial Compounds in the Volatilome of Social Spider Communities. Front Microbiol 2021; 12:700693. [PMID: 34504476 PMCID: PMC8422909 DOI: 10.3389/fmicb.2021.700693] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/31/2021] [Indexed: 11/24/2022] Open
Abstract
Social arthropods such as termites, ants, and bees are among others the most successful animal groups on earth. However, social arthropods face an elevated risk of infections due to the dense colony structure, which facilitates pathogen transmission. An interesting hypothesis is that social arthropods are protected by chemical compounds produced by the arthropods themselves, microbial symbionts, or plants they associate with. Stegodyphus dumicola is an African social spider species, inhabiting communal silk nests. Because of the complex three-dimensional structure of the spider nest antimicrobial volatile organic compounds (VOCs) are a promising protection against pathogens, because of their ability to diffuse through air-filled pores. We analyzed the volatilomes of S. dumicola, their nests, and capture webs in three locations in Namibia and assessed their antimicrobial potential. Volatilomes were collected using polydimethylsiloxane (PDMS) tubes and analyzed using GC/Q-TOF. We showed the presence of 199 VOCs and tentatively identified 53 VOCs. More than 40% of the tentatively identified VOCs are known for their antimicrobial activity. Here, six VOCs were confirmed by analyzing pure compounds namely acetophenone, 1,3-benzothiazole, 1-decanal, 2-decanone, 1-tetradecene, and docosane and for five of these compounds the antimicrobial activity were proven. The nest and web volatilomes had many VOCs in common, whereas the spider volatilomes were more differentiated. Clear differences were identified between the volatilomes from the different sampling sites which is likely justified by differences in the microbiomes of the spiders and nests, the plants, and the different climatic conditions. The results indicate the potential relevance of the volatilomes for the ecological success of S. dumicola.
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Affiliation(s)
- Alexander Lammers
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, Greifswald, Germany.,Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Hans Zweers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Tobias Sandfeld
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Paolina Garbeva
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Michael Lalk
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, Greifswald, Germany
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Enhanced Pharmaceutically Active Compounds Productivity from Streptomyces SUK 25: Optimization, Characterization, Mechanism and Techno-Economic Analysis. Molecules 2021; 26:molecules26092510. [PMID: 33923072 PMCID: PMC8123281 DOI: 10.3390/molecules26092510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 12/20/2022] Open
Abstract
The present research aimed to enhance the pharmaceutically active compounds’ (PhACs’) productivity from Streptomyces SUK 25 in submerged fermentation using response surface methodology (RSM) as a tool for optimization. Besides, the characteristics and mechanism of PhACs against methicillin-resistant Staphylococcus aureus were determined. Further, the techno-economic analysis of PhACs production was estimated. The independent factors include the following: incubation time, pH, temperature, shaker rotation speed, the concentration of glucose, mannitol, and asparagine, although the responses were the dry weight of crude extracts, minimum inhibitory concentration, and inhibition zone and were determined by RSM. The PhACs were characterized using GC-MS and FTIR, while the mechanism of action was determined using gene ontology extracted from DNA microarray data. The results revealed that the best operating parameters for the dry mass crude extracts production were 8.20 mg/L, the minimum inhibitory concentrations (MIC) value was 8.00 µg/mL, and an inhibition zone of 17.60 mm was determined after 12 days, pH 7, temperature 28 °C, shaker rotation speed 120 rpm, 1 g glucose /L, 3 g mannitol/L, and 0.5 g asparagine/L with R2 coefficient value of 0.70. The GC-MS and FTIR spectra confirmed the presence of 21 PhACs, and several functional groups were detected. The gene ontology revealed that 485 genes were upregulated and nine genes were downregulated. The specific and annual operation cost of the production of PhACs was U.S. Dollar (U.S.D) 48.61 per 100 mg compared to U.S.D 164.3/100 mg of the market price, indicating that it is economically cheaper than that at the market price.
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