Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br
Endophytes are primarily endosymbiotic bacteria and fungi that colonize the interior tissues of their host plant. They enhance the host plant’s growth and attenuate adverse effects of biological stress. Endophytic species of many indigenous plants are an untapped resource of plant growth-promoting m...
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| Format: | Article |
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MDPI AG
2023-02-01
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| Series: | Plants |
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| Online Access: | https://www.mdpi.com/2223-7747/12/3/638 |
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| author | Abdulazeez A. Ogbe Shubhpriya Gupta Wendy A. Stirk Jeffrey F. Finnie Johannes Van Staden |
| author_facet | Abdulazeez A. Ogbe Shubhpriya Gupta Wendy A. Stirk Jeffrey F. Finnie Johannes Van Staden |
| author_sort | Abdulazeez A. Ogbe |
| collection | DOAJ |
| description | Endophytes are primarily endosymbiotic bacteria and fungi that colonize the interior tissues of their host plant. They enhance the host plant’s growth and attenuate adverse effects of biological stress. Endophytic species of many indigenous plants are an untapped resource of plant growth-promoting microorganisms that can mitigate abiotic stress effects. Thus, this study aimed to isolate endophytes from the roots and leaves of the medicinal plant <i>Endostemon obtusifolius</i> to evaluate their in vitro growth-promoting capacities and drought tolerance and to characterize the most promising species. Twenty-six endophytes (fourteen bacteria and twelve fungi) were isolated and cultured from the roots and leaves of <i>E. obtusifolius</i>. All 26 endophytes produced flavonoids, and 14 strains produced phenolic compounds. Of the 11 strains that displayed good free radical scavenging capability (low IC<sub>50</sub>) in the 1-1-diphenyl-1-picryhydrazyl radical scavenging assay, only three strains could not survive the highest drought stress treatment (40% polyethylene glycol). These 11 strains were all positive for ammonia and siderophore production and only one strain failed to produce hydrogen cyanide and solubilize phosphate. Seven isolates showed aminocyclopropane-1-carboxylate deaminase activity and differentially synthesized indole-3-acetic acid. Using molecular tools, two promising symbiotic, drought stress tolerant, and plant growth-enhancing endophytic species (EORB-2 and EOLF-5) were identified as <i>Paenibacillus polymyxa</i> and <i>Fusarium oxysporum</i>. The results of this study demonstrate that <i>P. polymyxa</i> and <i>F. oxysporum</i> should be further investigated for their drought stress mitigation and plant growth enhancement effects as they have the potential to be developed for use in sustainable agricultural practices. |
| first_indexed | 2024-03-11T09:29:28Z |
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| language | English |
| last_indexed | 2024-03-11T09:29:28Z |
| publishDate | 2023-02-01 |
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| record_format | Article |
| series | Plants |
| spelling | doaj.art-79ad30a43415427ca9a6be999d1ec0e32023-11-16T17:45:15ZengMDPI AGPlants2223-77472023-02-0112363810.3390/plants12030638Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. BrAbdulazeez A. Ogbe0Shubhpriya Gupta1Wendy A. Stirk2Jeffrey F. Finnie3Johannes Van Staden4Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South AfricaResearch Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South AfricaResearch Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South AfricaResearch Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South AfricaResearch Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South AfricaEndophytes are primarily endosymbiotic bacteria and fungi that colonize the interior tissues of their host plant. They enhance the host plant’s growth and attenuate adverse effects of biological stress. Endophytic species of many indigenous plants are an untapped resource of plant growth-promoting microorganisms that can mitigate abiotic stress effects. Thus, this study aimed to isolate endophytes from the roots and leaves of the medicinal plant <i>Endostemon obtusifolius</i> to evaluate their in vitro growth-promoting capacities and drought tolerance and to characterize the most promising species. Twenty-six endophytes (fourteen bacteria and twelve fungi) were isolated and cultured from the roots and leaves of <i>E. obtusifolius</i>. All 26 endophytes produced flavonoids, and 14 strains produced phenolic compounds. Of the 11 strains that displayed good free radical scavenging capability (low IC<sub>50</sub>) in the 1-1-diphenyl-1-picryhydrazyl radical scavenging assay, only three strains could not survive the highest drought stress treatment (40% polyethylene glycol). These 11 strains were all positive for ammonia and siderophore production and only one strain failed to produce hydrogen cyanide and solubilize phosphate. Seven isolates showed aminocyclopropane-1-carboxylate deaminase activity and differentially synthesized indole-3-acetic acid. Using molecular tools, two promising symbiotic, drought stress tolerant, and plant growth-enhancing endophytic species (EORB-2 and EOLF-5) were identified as <i>Paenibacillus polymyxa</i> and <i>Fusarium oxysporum</i>. The results of this study demonstrate that <i>P. polymyxa</i> and <i>F. oxysporum</i> should be further investigated for their drought stress mitigation and plant growth enhancement effects as they have the potential to be developed for use in sustainable agricultural practices.https://www.mdpi.com/2223-7747/12/3/638abiotic stressLamiaceaemedicinal plantmicrobessecondary metabolite |
| spellingShingle | Abdulazeez A. Ogbe Shubhpriya Gupta Wendy A. Stirk Jeffrey F. Finnie Johannes Van Staden Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br Plants abiotic stress Lamiaceae medicinal plant microbes secondary metabolite |
| title | Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br |
| title_full | Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br |
| title_fullStr | Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br |
| title_full_unstemmed | Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br |
| title_short | Growth-Promoting Characteristics of Fungal and Bacterial Endophytes Isolated from a Drought-Tolerant Mint Species <i>Endostemon obtusifolius</i> (E. Mey. ex Benth.) N. E. Br |
| title_sort | growth promoting characteristics of fungal and bacterial endophytes isolated from a drought tolerant mint species i endostemon obtusifolius i e mey ex benth n e br |
| topic | abiotic stress Lamiaceae medicinal plant microbes secondary metabolite |
| url | https://www.mdpi.com/2223-7747/12/3/638 |
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