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Bacterial community associated with Acacia crassicarpa seeds and cotyledons

Dissertation (MSc (Microbiology))--University of Pretoria, 2022.

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Other Authors: Coutinho, Teresa A.
Format: Thesis
Language:English
Published: University of Pretoria 2023
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access_status_str Open Access
author2 Coutinho, Teresa A.
author_browse Coutinho, Teresa A.
author_facet Coutinho, Teresa A.
collection Thesis
dc_rights_str_mv © 2022 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 (Microbiology))--University of Pretoria, 2022.
format Thesis
id oai:repository.up.ac.za:2263/89739
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:37:22.574Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2023
publishDateRange 2023
publishDateSort 2023
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:2263/89739 Bacterial community associated with Acacia crassicarpa seeds and cotyledons Coutinho, Teresa A. malebecharmaine@gmail.com Shin, Gi Yoon Malebe, Mmapaseka Charmaine Acacia crassicarpa Microbiome 16S rRNA Amplicon sequencing Bacterial endophytes Multilocus sequence analysis (MLSA) UCTD Dissertation (MSc (Microbiology))--University of Pretoria, 2022. Acacia crassicarpa is widely planted in timber plantations for the pulp and paper industry but, this species is susceptible to diseases such as bacterial leaf blight. Xanthomonas campestris was described as the causal agent of this disease and was reported to be seedborne. However, isolation was not performed from the seeds and Koch’s postulate was not fulfilled Therefore, the aim of this study, was to isolate, identify, and characterize the bacterial leaf blight pathogen on A. crassicarpa and to study the bacterial community associated with A. crassicarpa seeds. Bacterial species were isolated from surface sterilized diseased leaves, symptomatic cotyledons, asymptomatic cotyledons, and seeds. Culture-dependent and independent methods were used to identify and characterize bacterial species of A. crassicarpa. Pantoea and Enterobacter species were the most isolated from diseased leaves. Pantoea species were also commonly isolated from symptomatic cotyledons. The dominant genera in asymptomatic cotyledons and seeds were Bacillus and Sphingobacterium species, respectively. Rhizobium was dominant in majority of A. crassicarpa seed genotypes based on the relative abundance plot. Statistical analysis showed that the difference between and within genotypes is not significant even though the observed species, community evenness and dominance between genotypes were slightly different. Although Xanthomonas species was not isolated, a potential pathogen was also isolated from both diseased leaves and symptomatic cotyledons using the culture-based method and identified with multi-locus sequence analysis (MLSA). Based on the sequences of two housekeeping genes (atpD and infB), the potential pathogen was identified as Pantoea stewartii subsp. indologenes. However, no disease symptoms were observed when this bacterium was inoculated into healthy A. crassicarpa seedlings. Several bacterial endophytic species were isolated and identified from different tissues of A. crassicarpa. These species could potentially promote the growth of woody species. These findings from the study will aid in future production and growth of healthy A. crassicarpa seedlings. NRF Biochemistry, Genetics and Microbiology (BGM) MSc (Microbiology) Unrestricted 2023-02-22T06:51:42Z 2023-02-22T06:51:42Z 2023 2022 Dissertation * A2023 https://repository.up.ac.za/handle/2263/89739 10.25403/UPresearchdata.22134728 en © 2022 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 Acacia crassicarpa
Microbiome
16S rRNA Amplicon sequencing
Bacterial endophytes
Multilocus sequence analysis (MLSA)
UCTD
Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title_full Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title_fullStr Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title_full_unstemmed Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title_short Bacterial community associated with Acacia crassicarpa seeds and cotyledons
title_sort bacterial community associated with acacia crassicarpa seeds and cotyledons
topic Acacia crassicarpa
Microbiome
16S rRNA Amplicon sequencing
Bacterial endophytes
Multilocus sequence analysis (MLSA)
UCTD
url https://repository.up.ac.za/handle/2263/89739