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Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat
Dissertation (MSc (Agric))--University of Pretoria, 2019.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2020
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| _version_ | 1867613518210007040 |
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| access_status_str | Open Access |
| author2 | Labuschagne, Nico |
| author_browse | Labuschagne, Nico |
| author_facet | Labuschagne, Nico |
| collection | Thesis |
| dc_rights_str_mv | © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Agric))--University of Pretoria, 2019. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/77860 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:25.198Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/77860 Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat Labuschagne, Nico u11158116@tuks.co.za Hassen, Abubeker Mulaudzi, Renolda Ipeleng UCTD Dissertation (MSc (Agric))--University of Pretoria, 2019. Plant growth promoting rhizobacteria (PGPR) are those bacteria that colonise the rhizosphere of various plants and promote growth either directly by improving nutrient uptake by the plant roots or indirectly through the control of pathogens. Due to the negative effects associated with the prolonged use of chemical fertilizers and fungicides, a lot of emphasis is now being given to research that investigates an alternative, sustainable and environmentally friendly method of crop production and protection. In the current study, a collection of rhizobacterial isolates from the University of Pretoria- Plant Growth Promoting Rhizobacteria (UP-PGPR) culture collection were screened for plant growth promotion and biocontrol activity against crown rot caused by Fusarium pseudograminearum on wheat (Triticum aestivum). A seedling tray bioassay was utilised as a rapid small-scale method to screen the rhizobacterial isolates for biocontrol activity against wheat crown rot in the greenhouse. The same method was also used to screen the isolates for direct plant growth promotion of wheat. Of all the isolates (113) screened for wheat crown rot control, 52% (59 isolates) significantly increased the shoot dry weight of the seedlings, 41% (46 isolates) increased the root dry weight of the seedlings, and the total seedling dry weight was increased by 32% (36 isolates) of the isolates. A seedling bioassay was also used to screen the isolates for direct plant growth promotion of wheat. Of the 113 isolates screened, 12% (14 isolates) increased the shoot dry weight of the seedlings, 22% (25 isolates) increased the dry weight of the roots; while the total dry weight of the seedlings was increased by 32% (36 isolates) of the isolates. Subsequent to the seedling bioassay in the greenhouse, the isolates were also assessed in vitro for selected traits associated with biocontrol activity and plant growth promotion. To test for a broad spectrum of biocontrol activity, in addition to F. pseudograminearum, the isolates were also screened for inhibition of Rhizoctonia solani, Phytophthora capsici and Macrophomina phaseolina. Almost 50% of the isolates displayed broad-spectrum activity against the pathogens on three different media. Some notable isolates in this regard were Bacillus sp. strain N54 and Pseudomonas sp. strain N59, N67 and N69. All isolates screened displayed multiple traits associated with biocontrol activity such as the production of antibiotic enzymes, volatiles (NH3 and HCN) and the production of siderophores. The isolates also displayed multiple traits associated with direct plant growth promotion (nitrogen fixation, phosphate solubilization, IAA and ACC deaminase). Based on the results obtained from the seedling bioassays in the greenhouse and the in vitro screening, a scoring system was developed, and the isolates were awarded points. Bacillus sp. strain A09AC, A17, A20, N02, N28, N54 Stenotrophomonas sp. strain A45, Pseudomonas sp. strain N04AC, N44 and N59A were selected for pot trials to confirm their F. pseudograminearum biocontrol efficacy (Figure 1.1). Bacillus sp. strain A10AC, Stenotrophomonas sp. strain A33, A43, A45, Paenibacillus sp. strain KBS1F3, Pseudomonas sp. strain N29, N69, N67, N76 and Pantoea sp. strain N34 were selected for use in pot trials in the greenhouse to confirm their efficacy as wheat growth promoters. The selected isolates were further assessed for biocontrol activity and plant growth promotion in greenhouse experiments. KBS1F3 (Paenibacillus alvei) showed the best results for wheat growth promotion while A17 (Bacillus cereus) gave the best results for biocontrol activity. The effect of temperature, pH, NaCl and different carbon sources on the growth of the isolates was also assessed in vitro. The optimum temperature of all isolates was observed to be between 26oC and 35oC while KBS1F3 was able to grow at 47oC and A17 at 50oC. The growth of KBS1F3 decreased with an increase in NaCl concentration while A17 still grew well at 4% NaCl concentration. All isolates grew optimally at pH 7. KBS1F3 still grew well at pH 8 while A17 showed good growth at all pH values except pH 4. All isolates showed the ability to utilise a variety of carbon sources. Microbiology and Plant Pathology MSc (Agric) Unrestricted 2020-12-29T11:50:58Z 2020-12-29T11:50:58Z 2020/04/24 2019 Dissertation Mulaudzi, RI 2019, Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat, MSc (Agric) Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/77860> A2020 http://hdl.handle.net/2263/77860 en © 2020 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title | Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title_full | Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title_fullStr | Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title_full_unstemmed | Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title_short | Assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against Fusarium pseudograminearum on wheat |
| title_sort | assessment of plant growth promoting rhizobacteria for plant growth enhancement and biocontrol activity against fusarium pseudograminearum on wheat |
| topic | UCTD |
| url | http://hdl.handle.net/2263/77860 |