Trichoderma as a functional fungal group in the rhizosphere of maize and wheat under conservation and conventional agricultural practices
| dc.contributor.advisor | Jacobs, Karin | en_ZA |
| dc.contributor.author | Ndaba, Nkosinathi Sthembiso | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Science. Dept. of Microbiology. | en_ZA |
| dc.date.accessioned | 2021-12-06T07:16:23Z | en_ZA |
| dc.date.accessioned | 2022-02-22T10:19:28Z | en_ZA |
| dc.date.available | 2021-12-06T07:16:23Z | en_ZA |
| dc.date.issued | 2021-12 | en_ZA |
| dc.description | Thesis (MSc) -- Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: The contribution of agriculture in South Africa to the economy, is one of those major drivers of employment in South Africa. The two most produced commercial crops in SA are maize and wheat. In chapter one, the importance of these crops and the effect of farming practices such as conventional and conservation agriculture were briefly compared and discussed. Furthermore, the importance of microorganisms in agriculture as well as their role in various biological processes that occurs in soil are briefly discussed. Particular attention was given to the role of Trichoderma spp. as they interact and form relationships with other soil organisms. This was followed by a brief discussion on the taxonomic history of Trichoderma spp. and the application of Trichoderma spp. in the industrial and agricultural sectors. Chapter two is the first of three research chapters and discussed the isolation and identification of Trichoderma species from wheat soil in the Western Cape. All isolates in this chapter were collected from agricultural soil only. The identification and classification of species was primarily based on macro features and amplification of internal transcribed spacer (ITS) regions. Thereafter, the final identification was done by combining two markers (ITS and Elongation factor 1 alpha (TEF1)). Ninety-one (91) strains of Trichoderma spp. which resolved into seven species that were identified as T. virens, T. saturnisporum, Trichoderma sp., T. gamsii, T. koningiopsis, T. velutinum, and T. spirale. It was also reported that T. gamsii was the predominant species. In addition, crop rotation practices resulted in a higher number of strains and species when it is compared with the monoculture practices. Chapter three is similar to Chapter 2 and focuses on the identification of Trichoderma species, on maize from different geographical areas in KwaZulu-Natal and the Free State. Soil samples were collected from sites with crop rotation as well as monoculture practices. From isolations, 337 strains were recovered from maize soil representing 11 Trichoderma species. Seven species have been isolated previously in South Africa. However, five species namely, T. velutinum, T. rifaii, T. paratroviride, T. neokoningii and T. peberdyi are being reported for the first time in South Africa. Distribution of the species significantly differed between crop rotation and monoculture practices, with crop rotation sites resulting in a higher number of species than monoculture practices. Furthermore, T. gamsii and T. hamatum were the most abundant species isolated. In chapter four the potential functions of different strains were investigated. The results suggest that each certain function in Trichoderma spp. could be strain specific. This chapter determined the abilities of Trichoderma strains to solubilize phosphate and produce indole acetic acid. These two metabolic factors (solubilization of phosphate and production of indole acetic acid) were evaluated because it is known that they could be used for primary identification of species that might have the capacity to improve plant growth. Findings indicated that the majority of strains were able to solubilize phosphate and pH reduction play a vital role in this case. T. koningiopsis NNC066 solubilized the maximum amount of phosphate whereas Trichoderma sp. K4 solubilized the least amount of phosphate. Moreover, no strains were able to produce indole acetic acid (IAA) in the absence of tryptophan (L-TRP). Although, the amendments of the media with L-TRP, enabled all strains to produce the IAA where maximum amount obtained at 41.90 µg/ml by T. gamsii NNC019, while the least amount was at 0.30 µg/ml by Trichoderma sp. K1. | en_ZA |
| dc.description.abstract | AFRIKAANS OPSOMMING: Die bydrae van die landbou in Suid -Afrika tot die ekonomie, is een van die belangrikste dryfvere vir werk in Suid -Afrika. Die twee mees geproduseerde kommersiële gewasse in SA, is mielies en koring. In hoofstuk een is die belangrikheid van hierdie gewasse en die effek van boerderypraktyke soos konvensionele en bewaringslandbou kortliks vergelyk en bespreek. Verder word die belangrikheid van mikroörganismes in die landbou sowel as hul rol in verskillende biologiese prosesse wat in die grond voorkom, kortliks bespreek. Spesifieke aandag is gegee aan die rol van Trichoderma spp. as hulle interaksie het en verhoudings met ander grondorganismes vorm. Dit is gevolg deur 'n kort bespreking oor die taksonomiese geskiedenis van Trichoderma spp. en die toepassing van Trichoderma spp. in die industriële en landbousektor. Hoofstuk twee is die eerste van drie navorsingshoofstukke en bespreek die isolasie en identifisering van Trichoderma -spesies uit koringgrond in die Wes -Kaap. Alle isolate in hierdie hoofstuk is slegs uit landbougrond versamel. Die identifisering en klassifikasie van spesies was hoofsaaklik gebaseer op makrokenmerke en versterking van interne getranskribeerde afstandhouers (ITS) streke. Daarna is die finale identifikasie gedoen deur twee merkers (ITS en Elongation factor 1 alpha (TEF1)) te kombineer. Een-en-negentig (91) stamme van Trichoderma spp. wat opgeneem het in sewe spesies wat geïdentifiseer is as T. virens, T. saturnisporum, Trichoderma sp., T. gamsii, T. koningiopsis, T. velutinum en T. spirale. Daar is ook berig dat T. gamsii die oorheersende spesie is. Boonop het wisselboupraktyke 'n groter aantal stamme en spesies tot gevolg gehad as dit vergelyk word met die monokultuurpraktyke. Hoofstuk drie is soortgelyk aan hoofstuk 2 en fokus op die identifisering van Trichoderma-spesies, op mielies uit verskillende geografiese gebiede in KwaZulu-Natal en die Vrystaat. Grondmonsters is versamel vanaf terreine met wisselbou sowel as monokultuurpraktyke. Uit isolasies is 337 stamme gevind uit mieliegrond wat 11 Trichoderma -spesies verteenwoordig. Sewe spesies is voorheen in Suid -Afrika geïsoleer. Vyf spesies, naamlik T. velutinum, T. rifaii, T. paratroviride, T. neokoningii en T. peberdyi, word egter vir die eerste keer in Suid -Afrika aangemeld. Die verspreiding van die spesies het aansienlik verskil tussen wisselbou- en monokultuurpraktyke, met wisselbouplekke wat 'n groter aantal spesies as monokultuurpraktyke tot gevolg gehad het. Verder was T. gamsii en T. hamatum die mees voorkomende spesies wat geïsoleer is. In hoofstuk vier is die moontlike funksies van verskillende stamme ondersoek. Die resultate dui daarop dat elke sekere funksie in Trichoderma spp. kan stamspesifiek wees. Hierdie hoofstuk bepaal die vermoëns van Trichoderma -stamme om fosfaat op te los en indool -asynsuur te produseer. Hierdie twee metaboliese faktore (oplosbaarheid van fosfaat en produksie van indool -asynsuur) is geëvalueer omdat dit bekend is dat dit gebruik kan word vir primêre identifisering van spesies wat die vermoë het om plantgroei te verbeter. Bevindings het aangedui dat die meerderheid stamme fosfaat kon oplos en pH - vermindering speel in hierdie geval 'n belangrike rol. T. koningiopsis NNC066 het die maksimum hoeveelheid fosfaat opgelos terwyl Trichoderma sp. K4 het die minste hoeveelheid fosfaat opgelos. Boonop kon geen stamme indool-asynsuur (IAA) produseer in die afwesigheid van tryptofaan (L-TRP). Alhoewel die wysigings van die media met L-TRP alle stamme in staat gestel het om die IAA te produseer waar die maksimum hoeveelheid op 41,90 µg/ml verkry is deur T. gamsii NNC019, terwyl die minste hoeveelheid op 0,30 µg/ml was deur Trichoderma sp. K1. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.embargo.terms | 2022-06-06 | en_ZA |
| dc.format.extent | xi, 175 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/124239 | en_ZA |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Soil microbiology | en_ZA |
| dc.subject | Agriculture -- South Africa | en_ZA |
| dc.subject | Fungal communities | en_ZA |
| dc.subject | Crops and soils -- South Africa | en_ZA |
| dc.subject | Trichoderma | en_ZA |
| dc.title | Trichoderma as a functional fungal group in the rhizosphere of maize and wheat under conservation and conventional agricultural practices | en_ZA |
| dc.type | Thesis | en_ZA |