Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on June 29, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy Plant Science, Department of Agricultural, Food and Nutritional Science, University of Alberta." Includes bibliographical references.

Thesis (Ph.D.) - University of KwaZulu-Natal, Pietermaritzburg, 2007. / Full text also available online. Scroll down for electronic link.

Thesis (M.Sc.) - University of KwaZulu-Natal, Pietermaritzburg, 2007. / Full text also available online. Scroll down for electronic link.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Phytoplasma diseases have caused disastrous effects in vineyards around the world. Therefore, the recent discovery of phytoplasmas in South African vineyards could be highly detrimental to the local wine industry. Antimicrobial peptides (AMPs) are small molecules expressed by almost all organisms as part of their non-specific defence system. These peptides can offer protection against a wide variety of bacterial and fungal pathogens in plants. Due to the fact that phytoplasmas lack an outer membrane and cell wall, AMPs are considered to be perfect candidates to confer resistance to this phytopathogen. The current study intends to explore the in planta activity of AMPs against the grapevine pathogen aster yellows phytoplasma (AYp) through Agrobacterium-mediated transient expression. The AMPs, Vv-AMP1, D4E1 and Snakin1 (isolated from potato and grapevine) were selected to be tested for their in planta effect against AYp. Cauliflower mosaic virus 35S expression vectors containing four different AMP-encoding sequences were therefore constructed. As an alternative method to observe the effect Vv-AMP1 might have on AYp in planta, grafting of Vv-AMP1 transgenic Vitis vinifera cv "Sultana‟ plant material was used. To allow assumptions about AMP efficacy in this transient expression system, attempts were made to describe the spatial distribution and pathogen titre of AYp in V. vinifera cv "Chardonnay‟ material. Additionally, transmission experiments were carried out to infect Catharanthus roseus and Nicotiana benthamiana with AYp through the insect vector Mgenia fuscovaria. Material was screened for AYp infection by a nested-PCR procedure using universal primers described by Gundersen and Lee (1996). For quantification of AYp infection, a semi-quantitative real-time PCR (qPCR) protocol was optimized, using the SYBR Green-based system. In total, 86 V. vinifera cv "Chardonnay‟ plantlets were screened for AYp infection two-, three-, four-, seven- and eleven weeks after introduction into in vitro conditions. No AYp infection could however be detected and plantlets displayed a "recovery phenotype‟. To examine the distribution of AYp in canes of an infected V. vinifera cv "Chardonnay‟ plant, leaf and the corresponding node material from five canes were screened by a nested-PCR procedure. It can be concluded, that AYp was found predominantly in the nodes when compared to leaf material in the late season of the year. It is also highly unlikely for leaf material to show phytoplasma infection, if in the corresponding node no AYp could be detected. As AYp-infected grapevine material could not be maintained in vitro, the effect of VvAMP-1 transgenic grapevine against AYp could not be tested. Infection of C. roseus and N. benthamiana plants with AYp was successfully achieved by insect vector transmission experiments. Transient expression assays were conducted on AYp-infected N. benthamiana material. Quantification of phytoplasma in this material showed a decrease of AYp in both the AMP treatment groups and the control groups. This study optimized a qPCR procedure to detect and quantify AYp in infected plant material. The Agrobacterium-mediated transient expression system used during this study was not reliable, as no significant effect of the AMPs on AYp titre could be observed. This study showed, that AYp cannot be established and maintained in in vitro cultured V. vinifera cv "Chardonnay‟ material, and tissue culture itself might therefore be a way to eradicate AYp in this cultivar. To our knowledge, this study is the first to report on the spatial distribution of AYp in canes of an infected V. vinifera cv "Chardonnay‟ vine. / AFRIKAANSE OPSOMMING: Fitoplasma siektes veroorsaak ramspoedige gevolge in wingerde oor die hele wêreld. Dus kan die onlangse ontdekking van fitoplasma in Suid-Afrikaanse wingerde baie nadelige gevolge vir die plaaslike wynbedryf beteken. Antimikrobiese peptiede (AMPe) is klein molekules wat in amper al organismes as deel van hulle nie-spesifieke verdedegingsstelsel tot uitdruk kom. Hierdie peptiede kan beskerming aanbied teen ʼn wye verskeidenheid van bakteriële en swampatogene in plante. As gevolg van die feit dat fitoplasmas geen buitenste membraan en selwand het nie, word AMPe oorweeg as middle om weerstand te verleen teen hierdie fitopatogene. Die huidige studie beoog om die in planta aktiwiteit an AMPe teen die wingerdstok patogeen aster geel fitoplasma (AYp) deur middle van Agrobakteriumbemiddelde tydelike uitdrukkingssiteme, te ondersoek. Die AMPe, Vv-AMP1, D4E1 en Snakin1 (geïsoleer van aartappel en wingerd plante) is gekies om getoets te word vir hul in planta effek teen AYp. Blomkoolmosaïek-viruse 35S uitdrukkingsvektore met vier verskillende AMP-kodering rye, is dus ontwikkel. As ʼn aternatiewe method om die moontlike effek van Vv-AMP1 op AYp in planta in ag te neem, is oorplantings van die Vv-AMP1 transgeniese Vitis vinifera cv "Sultana‟ plantmateriaal gebruik. Om voorsiening te maak vir AMPe se doeltreffenheid in hierdie tydelike uitdrukkingsvektore, is pogings aangewend om die ruimlike verspreiding en patogeen konsentrasie van AYp in V. vinifera cv "Chardonnay‟ te beskryf. Addisioneel is transmissie eksperimente uitgevoer om Catharanthus roseus en Nicotania benthamiana te besmet met AYp deur die insekvektor, Mgenia fuscovaria. Plantmateriaal is getoets vir AYp deur van ʼn PCR protokol gebruik te maak met universele inleiers (grondlae) soos beskyf deur Grundersen en Lee (1996). Vir kwantifiseering van die AYp infeksie, is n semi-kwantitatiewe qPCR protokol geoptimaliseer, met hulp van die SYBR Groen-gebaseerde stelsel. In geheel is 86 V. vinifera cv "Chardonnay‟ planties getoets vir AYp infeksie – twee-, drie-, vier-, sewe- en elf weke na die bekendstelling aan die in vitro voorwaardes. Geen AYp infeksie kon egter opgespoor word en die plante het “herstel fenotipe‟ vertoon. Om die verspreiding van AYp in stingelknope van ʼn besemtte V. vinifera cv "Cardonnay‟ plant, blaar en ooreenstemmende stingelknope uit vyf stingels te ondersoek, is hulle getoets deur ʼn PCR protokol. Daar kon afgelei word dat AYp hoofsaaklik in die stingelknop in vergelyking met die blaarmaterial laat in die season, gevind word. Dit is hoogs oonwaarskynlik om fitoplasma infeksies in blaarmaterial te vind, as in die ooreenstemmende stingelknop daar geen AYp oopgespoor kon word nie. As gevolge daarvan dat die AYp-geinfekteerde wingerdmateriaal nie in vitro gegroei kon word nie, kon die effek van VvAMP-1 transgeniese wingerd teen AYp nie getoets word nie. Infeksies van C. roseus en N. benthamiana plante met AYp is suksesvol bereik deur transmissie eksperiemente. met ʼn insekvektor. Tydellike uitdrukkingvektore toetse is uitgevoer op die AYp besmette N. benthamiana material. Kwantifisering van fitoplasma in hierdie material het die afname van AYp in altwee, die AMP behandelings groepe en die kontrole groepe getoon. Hierdie studie het ʼn qPCR geoptimaliseer om besmette plantmaterial met AYp op te spoor en dit te kwantifiseer. Die Agrobacterium-bemiddelde tydelike uitdrukingsvektore wat in hierdie studie gebruik is, was nie vertroubaar genoeg, want geen beduidelike effek van die AMPe op AYp konsentrasie kon waargeneen word nie. Hierdie studie het bewys dat AYp nie vasgestel is en in stand gehou kan word deur in vitro aankweeking van V. vinifera cv "Chardonnay‟ material nie, en weefselkulture kan dus ʼn manier wees om AYp in hierdie kultivar uit te roei. Tot kennis, is hierdie studie die eerste studie om die ruimtelike verspreiding van AYp in stingelknope van ʼn besmette V. vinifera cv "Chardonnay‟ wingerstok te rapporteur. / Winetech and DAAD

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The aim of this study on grapevine was to genetically characterise, validate and map the reported fungal disease resistance genes of Pölöskei Muskotály (PM), Kishmish Vatkana (KV) and Villard Blanc (VB) in South Africa using QTL analysis. These fungal resistant parents were crossed with other varieties that have desirable fruit qualities in an effort to combine fungal disease resistance with desirable fruit qualities in a single variety. The genetic basis of PM’s resistance to downy and powdery mildew has not been investigated before. It does however have VB in its pedigree so the assumption was made that the same QTL/genes present in VB contribute to this resistance. KV’s resistance to powdery mildew reportedly originates from the REN1 gene located on chromosome 13. VB’s powdery and downy mildew resistance is conferred by QTL present on chromosome 15 and chromosome 18 respectively and has been reported in numerous studies. The study populations comprised of 124 F1 PM x Regal Seedless plants, 16 F1 PM x G4-3418 plants, 14 F1 PM x Sunred Seedless plants, 158 F1 Sunred Seedless x KV plants and 250 F1 VB x G1-6604 plants. DNA was extracted from the leaves and all plants were screened using microsatellite markers. Phenotypic evaluations of downy and/or powdery mildew resistance were performed on the appropriate populations. The molecular data was used to generate linkage maps and combined with phenotypic data to perform QTL analysis. From the molecular data generated for the three PM populations it was determined that the F1 progeny inherited almost exclusively maternal alleles, and could not be used in a mapping study. These populations were eliminated from the study and PM will be used as a pollen donor in future. Molecular data from the Sunred Seedless x KV cross was used to generate a linkage map for chromosome 13 comprising eight markers and spanning 45.6 cM. When combined with the data from two powdery mildew phenotypic screens a QTL peak spanning the REN1 gene on chromosome 13 of KV was identified. This locus explains between 44.8% and 57.7% of the phenotypic variance observed. The molecular data from the VB x G1-6604 cross was used to generate partial linkage maps for chromosome 15 and 18. Eleven markers were mapped on chromosome 15 spanning 56.4 cM, and ten markers were mapped on chromosome 18 spanning 101.8 cM. When the chromosome 15 linkage map was combined with the data from two powdery mildew phenotypic screens a QTL associated with powdery mildew resistance was identified on chromosome 15 that explains between 18.9% and 23.9% of the phenotypic variance observed. Likewise a QTL associated with downy mildew resistance was identified on chromosome 18 when the chromosome 18 linkage map was combined with data from two downy mildew phenotypic screens. This QTL explains between 19.1% and 21.2% of the phenotypic variance observed. This study succeeded in genetically characterising the fungal disease resistance genes of two different sources of grapevine and provided exclusionary information on a third resistance source for future breeding applications. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie in wingerd was om die genetiese komponent van die swamweerstandsgene van Pölöskei Muskotály (PM), Kishmish Vatkana (KV) and Villard Blanc (VB) in Suid-Afrika te karakteriseer en die teenwoordigheid daarvan te bevestig deur ʼn Kwantitatiewe Eienskap Lokus (KEL) benadering te volg. In ʼn poging om swamweerstand en goeie vrugeienskappe te kombineer in ʼn enkel variëteit is die weerstandige variëteite met vatbare variëteite gekruis wat goeie vrugeienskappe besit. Die genetiese basis van PM se weerstand teen donsskimmel en witroes is nog nie vantevore bestudeer nie. VB is een van sy voorgeslagte en daar is aangeneem dat dieselfde KEL/gene waarskynlik verantwoordelik is vir die weerstand. Dit is gerapporteer dat KV se witroesweerstand afkomstig is van die REN1 geen op chromosoom 13. Vele publikasies rapporteer VB se weerstand teen witroes en donsskimmel Beide die witroes- en donsskimmelweerstand word oorgedra deur KEL teenwoordig op chromosome 15 en 18 onderskeidelik. Die populasies gebruik in hierdie studie het bestaan uit 124 F1 PM x Regal Seedless plante, 16 F1 PM x G4-3418 plante, 14 F1 PM x Sunred Seedless, 158 F1 Sunred Seedless x KV plante en 250 F1 VB x G1-6604 plante onderskeidelik. Blare is versamel vir DNS isolasie en genotipering met mikrosatellietmerkers. Al drie populasies se weerstand teen donsskimmel en/of witroes is fenotipies geëvalueer. Die molekulêre data is gebruik om genetiese koppelingskaarte op te stel en gekombineer met die fenotipiese data om KEL analise uit te voer. Die molekulêre data van die drie PM populasies het daarop gedui dat die F1 nageslag amper uitsluitlik moederlike allele geërf het en kon gevolglik nie gebruik word in die studie nie. Die PM populasies is uitgesluit uit hierdie studie en PM sal voortaan as stuifmeelskenker gebruik word. Molekulêre data van die Sunred Seedless x KV kruising is gebruik om ʼn koppelingskaart vir chromosoom 13 op te stel wat 45.6 cM lank is en agt merkers bevat. Die KEL analise van die koppelingskaart en twee fenotipiese datastelle vir witroes het ʼn KEL piek geïdentifiseer wat oor die lengte van die REN1 geen-interval strek. Hierdie lokus is verantwoordelik vir 44.8% tot 57.7% van die fenotipiese variasie wat waargeneem word. Molekulêre data van die VB x G1-6604 kruising is gebruik om gedeeltelike koppelingskaarte vir chromosome 15 en 18 op te stel. Elf merkers karteer op die chromosoom 15 kaart van 56.4 cM en tien merkers karteer op die chromosoom 18 kaart van 101.8 cM. KEL analise van chromosoom 15 se koppelingskaart en twee witroes fenotipiese datastelle het ʼn KEL geïdentifiseer wat 18.9% tot 23.9% van die fenotipiese variasie verduidelik. ʼn KEL is ook op chromosoom 18 geïdentifiseer wat 19.1% tot 21.2% van die fenotipiese variasie verduidelik met die gekombineerde analise van chromosoom 18 se koppelingskaart en twee donsskimmel fenotipiese datastelle. Hierdie studie het die genetiese komponent van die swamweerstandsgene van twee Vitis variëteite suksesvol gekarakteriseer en bevestig. Waardevolle telingsinligting oor die derde variëteit is ook onthul.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Leaf blackening, a postharvest disorder which is characterized by a dark brown to black discoloration, is found in most commercially important Protea cut flower species and cultivars. As this disorder is known to increase with storage time, it is a major concern to the South African industry as the use of sea freight is increasingly preferred due to lower transport costs and a more favourable carbon footprint. The cause of leaf blackening has been strongly linked to a carbohydrate stress exerted by the large inflorescence, thus requiring the utilization of sugar bound polyphenols in the foliage, which when removed, can oxidize enzymatically or non-enzymatically. A study where harvesting was done throughout the season as well as on selected days at 08:00, 12:00, 15:00 and 17:00, concluded that leaf blackening incidences in Protea cv. Sylvia stems varies significantly throughout the season, between years and even with the harvest time of day. Leaf blackening incidences increased from October onwards and remained high until February, before decreasing to acceptably lower levels towards March to May. Carbohydrate- and phenolic content together with water status of leaves at harvest was not able to accurately predict incidence of the associated leaf blackening. However, irrespective of the season of harvesting, leaf blackening was significantly lower when stems were harvested later in the day than compared to stems harvested in the morning. Low sucrose and high water content at these harvest times was positively correlated to high incidences of leaf blackening. In a next study where uptake dynamics of glucose pulsing was investigated, Protea cv. Sylvia was harvested at different times throughout the day, dehydrated to various levels and pulsed with an increasing range of glucose concentrations. Pulsing solution uptake per stem was found to be highly influenced by these factors, as dehydration of stems and a harvest time later during the day both decreased stem water potential, which then increased pulse-solution uptake within a certain time period. The daily harvest time influenced transpiration, whilst pulse-solution uptake decreased with an increase in glucose pulse concentration. When stems were pulsed pre-storage with an increasing range of glucose concentrations, not only did pulses of between 4.7 – 13.7% glucose significantly delayed the incidence of leaf blackening, but it also maintained a positive water balance longer in stems during vase life. Ethanol or acetaldehyde vapour did not provide a viable alternative for reducing leaf blackening incidence in Protea cv. Sylvia, although a synergistic effect was found when ethanol vapour or pulsing was used in combination with glucose. A commercial verification trial disclosed that Protea magnifica and Protea ‘Pink Ice’ reacted more beneficial to ethanol vapour than was observed in ‘Sylvia’. This study confirms that carbohydrate availability within the Protea cut stem remains a key factor in the control of leaf blackening. Factors which assist in maintaining high internal carbohydrate levels, such as enhanced glucose pulse uptake or effective vase solution utilization will contribute to providing an optimum control of leaf blackening during vase life following long-term cold storage. / AFRIKAANSE OPSOMMING: Loofblaarverbruining is ‘n na-oes defek wat gekarakteriseer word deur ‘n donker bruin na swart verkleuring wat voorkom in meeste kommersieël belangrike Protea snyblom spesies en kultivars. Hierdie defek is bekend daarvoor dat dit toeneem met stoortyd, dus is dit ‘n groot kommer vir die Suid-Afrikaanse industrie, met toenemende gebruik van seevrag as vervoer keuse wat laer vervoer kostes en meer gunstige ‘koolstof voetspoor’ bevoordeel. Die oorsaak van loofblaarverbruining word sterk gekoppel aan ‘n koolhidraat stres wat uitgeoefen word deur die groot bloeiwyse op die loofblare, waar suiker-gebonde polifenoliese verbindings ensiematies of nieensiematies geoksideer word met die verwydering van die suiker verbinding. 'n Studie waar geoes was regdeur die seisoen, sowel as op geselekteerde dae om 08:00, 12:00, 15:00 en 17:00, het bevind dat die voorkoms van loofblaarverbruining in stele van Protea kv. Sylvia aansienlik geskil regdeur die seisoen, tussen jare en selfs met die oes tyd gedurende die dag. Die voorkoms van loofblaarverbruining het toegeneem vanaf Oktober en het hoog gebly tot en met Februarie, voordat dit gedaal het tot aanvaarbare laer vlakke teen Maart, tot en met Mei. Koolhidraat-en fenoliese inhoud sowel as die water status van die blare by oes was onsuksesvol om die voorkoms van die gepaardgaande loofblaarverbruining akkuraat te voorspel. Loofblaarverbruining was egter aansienlik laer as stele geoes later in die dag teenoor stele geoes in die oggend, ongeag die seisoen van oes. Lae sukrose en 'n hoë water inhoud geassosieer met hierdie oes-tye was positief gekorreleerd met ‘n hoë voorkoms van loofblaarverbruining. In 'n volgende studie waar die opname dinamika van glukose pulsing ondersoek was, is Protea kv. Sylvia stele geoes op verskillende tye dwarsdeur die dag, gedehidreer tot verskillende vlakke en met 'n toenemende reeks van glukose konsentrasies gepuls. Pulsoplossing opname per steel is sterk beïnvloed deur hierdie faktore, aangesien dehidrasie van die stele asook stele geoes later gedurende die dag die afname van steel waterpotensiaal veroorsaak het, terwyl die puls-oplossing opname versnel het binne ‘n bepaalde tyd. Die tyd van oes beïnvloed ook transpirasie, terwyl vaas oplossing opname afgeneem met 'n toename in glukose puls konsentrasie. Wanneer ‘Sylvia’ stele gepuls was voor stoor met 'n reeks van toenemende glukose konsentrasies, het nie net die puls van tussen 4.7 – 13.7% glukose aansienlik die voorkoms van loofblaarverbruining vertraag nie, maar dit het ook ‘n positiewe water balans langer in stele gedurende die vaas lewe behou. Nie etanol of asetaldehied dampe is bevind as geskikte alternatief vir glukose pulsing om die voorkoms van loofblaarverbruining in Protea kv. Sylvia te verlaag nie, alhoewel ‘n sinergistiese effek waargeneem was wanneer etanol in kombinasie met glukose gebruik was. ‘n Kommersieële bevestigingstoetsing het bevind dat Protea magnifica en ‘Pink Ice’ meer voordeel uit ‘n ethanoldamp behandeling kon trek teenoor ‘Sylvia’. Hierdie studie het bevestig die belangrikheid van koolhidraat beskikbaarheid in die Protea snyblom, vir beheer van loofblaarverbruining. Faktore wat die handhawing van hoë interne koolhidrate vlakke, soos bevorderde glukose puls opname of effektiewe vaas oplossing benutting sal bydra tot ‘n optimal beheer van loofblaarverbruining tydens vaas lewe na langtermyn koueopberging. / National Research Fund (NRF) for their financial support in 2009; Protea Producers of South Africa (PPSA) and Productschap Tuinbouw (PT) as well as the Frank Batchelor Will Trust Grant for the financial support.

The history of cultivating barley dates back to the beginning of conscious agriculture, accompanying humans together with wheat, as the second oldest grain. It is not possible to understand the current role barley plays in our economy only from the perspective of its use of malting, although we regard it as a priority, both in light of breeding and cultivating, and its research. With regard to the short growing season, the weaker root system and its biological character, barley reacts sensitive to stressful conditions of all kind, and thus also to any br1eeding mistake. Throughout its entire vegetation period, spring barley is exposed to the pressure of a number of fungal diseases. Especially in regard to the malting barley, it is necessary to fight against this danger effectively. High demands are put on the quality of malting barley and diseases can - to a large extent - decide on economic breeding results. It says: For successful breeding of malting barley, its outcome is the tax of the complex breeding proceedings. The fight against fungal diseases is a significant part of agricultural engineering. A series of preparations against fungal diseases exist and further registrations of preparations continue to occur. The laboratory Kluky s.r.o. is one of the companies that makes registered experiments of the preparations. Within this recognized laboratory, the experiment of monitoring diseases of the spring barley was carried out while applying chosen beneficent substances.

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-05-20T18:06:29Z No. of bitstreams: 0 / Made available in DSpace on 2015-05-20T18:06:29Z (GMT). No. of bitstreams: 0 / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP