L'endosymbiose racinaire entre les plantes et les champignons mycorhiziens à arbuscules (CMA) permet aux plantes d'avoir un meilleur accès aux nutriments du sol. Pour cette raison, cette endosymbiose joue un rôle majeur dans les écosystèmes et pour l'agriculture durable. Les étapes clés de la colonisation des racines par les CMA sont: 1) la pénétration des CMA dans le système racinaire à travers les cellules de l'épiderme et du cortex externe, et 2) la formation dans les cellules du cortex interne d'une structure ramifiée appelée arbuscule, qui permet des échanges entre les cellules végétales et les hyphes fongiques. L'établissement de cette symbiose implique une communication entre les deux partenaires. Les plantes produisent des hormones, les strigolactones qui induisent chez les CMA la production de signaux symbiotiques : des lipo-chitooligosaccharides (Myc-LCO) et des chitooligosaccharides courts (Myc-COs). Les Myc-LCO et les Myc-CO induisent des réponses moléculaires et physiologiques chez les plantes qui sont capables de former des mycorhizes à arbuscules. Cependant, leur rôle exact dans l'établissement des mycorhizes à arbuscules n'est pas connu. La difficulté à cultiver et transformer le partenaire fongique de cette symbiose rend la recherche compliquée du côté fongique. Du côté des plantes, on sait que des membres de la famille des récepteurs kinases à domaines lysin (LysM-RLK) perçoivent des LCO et des CO produits par divers microorganismes et sont donc de bons candidats pour percevoir des Myc-LCO et des Myc-CO. La plupart des recherches sur les mycorhizes à arbuscules sont réalisées chez des légumineuses, espèces chez lesquelles plusieurs duplications de gènes codant les LysM-RLK ont eu lieu. J'ai donc utilisé lors de mon doctorat des Solanaceae (Solanum lycopersicum, Petunia hybrida et Nicotiana benthamiana) pour étudier le rôle de deux récepteurs putatifs de Myc- LCO, codés par les gènes LYK10 et LYK4. Ces deux gènes, physiquement proches l'un de l'autre dans les génomes de la plupart des dicotylédones, proviennent probablement d'une ancienne duplication en tandem. En utilisant une approche biochimique, nous avons montré que SlLYK10 de S. lycopersicum est capable de lier des LCO avec une haute affinité. De plus, j'ai montré que le promoteur de SlLYK10 est exprimé dans l'épiderme et le cortex externe avant la colonisation par les CMA, puis dans des cellules contenant des arbuscules au cours de la colonisation par les CMA. Enfin, des approches de génétique inverse chez la tomate et le pétunia ont permis de démontrer que LYK10 contrôle la pénétration des CMA dans les racines et la formation des arbuscules. Ces résultats suggèrent que LYK10 perçoit les LCO et active chez les plantes la machinerie nécessaire à la pénétration de CMA dans les cellules végétales et à la formation des arbuscules. / The root endosymbiosis between plants and arbuscular mycorrhizal fungi (AMF) allows the plants to have a better access to soil nutrients. For this reason this endosymbiosis plays a major role in ecosystems and in sustainable agriculture. The key steps for AMF colonization are: 1) the AMF penetration in the root system through crossing epidermal/outer cortical cells, and 2) the formation of a branched inner cortex structure called arbuscules that permits exchanges between plant cells and fungal hyphae. The establishment of this symbiosis involves communication between the two partners of the symbiosis. Plants produce strigolactones, hormones that induce in AMF the production of symbiotic signals : lipo-chitooligosaccharides (Myc-LCOs) and short chitooligosaccharides (Myc-COs). Both Myc-LCOs and Myc-COs induce plant molecular and physiological responses known to be associated with the formation of arbuscular mycorrhiza (AM). However, theit exact role in AM establishment is unknown. The difficulty to grow and transform the fungal partner of this symbiosis makes the research complicated on the fungal side. On the plant side, members of the lysin motif receptor-like kinase (LysM-RLK) family are known to perceive LCOs and COs produced by various microorganisms and are thus good candidates to perceive Myc-LCOs and Myc-COs. Most of the laboratory researches on AM conducted worldwide are performed on legumes where the LysM-RLK family has encountered several gene duplications. During my PhD I used Solanaceae species (Solanum lycopersicum, Petunia hybrida and Nicotiana benthamiana) to study the role of two candidate Myc-LCO receptors encoded by the genes LYK10 and LYK4. These two genes are physically close to each other in genomes of most of the dicotyledons and likely originate from of an ancient tandem duplication. By using a biochemical approach, we showed that S. lycopersicum SlLYK10 is able to bind LCOs with high affinity. Moreover, I showed that SlLYK10 promoter is expressed in epidermis/outer cortex before AMF colonization and also in arbuscule-containing cells during colonization. Finally, reverse genetic approaches in tomato and petunia allowed demonstrating that LYK10 controls AMF penetration into the roots and arbuscule formation. Taken together, these results suggest that LYK10 perceive LCOs and induce/activate the plant machinery required for AMF penetration into plant cells. Altogether this strongly suggests that LCOs play a role in AMF perception by plant during AM establishment. By using the same approaches, we found that N. benthamiana NbLYK4, as its orthologs in legumes and other dicotyledons, also binds LCOs with high affinity and is involved in AM establishment and plant defence. NbLYK4-silenced plants showed reduced responses to defence elicitors and increased colonization by pathogens and AMF. This led to the hypothesis that LYK4 perceives LCOs and locally inhibits plant defence during AMF colonization. This strongly suggests that Myc-LCOs are able to regulate plant defence. In conclusion, at least two proteins are involved non-redundantly in LCO perception in Solanaceae, LYK10 and LYK4 and regulates complementary plant machineries required for AMF colonization.

Made available in DSpace on 2014-06-11T19:26:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-23Bitstream added on 2014-06-13T19:13:50Z : No. of bitstreams: 1 abrahao_c_me_botfca.pdf: 1392228 bytes, checksum: b2bc10c79c3c60bc1886ca1c98976398 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O consumo de mini tomate tem crescido nos últimos anos, devido à maior exigência dos consumidores em qualidade e diversidade de produtos. Dessa forma, o manejo da solução nutritiva é um fator crucial para a obtenção de elevada produção e qualidade do tomateiro, incluindo as concentrações e as relações entre os elementos. O presente estudo foi desenvolvido com o objetivo de avaliar seis relações entre K, Ca e Mg na produção e na qualidade de duas cultivares de mini tomate cultivadas em substrato, sob ambiente protegido, em duas épocas de cultivo. Os experimentos foram realizados na área experimental do Departamento de Recursos Naturais, Ciência do solo, pertencente à Universidade Estadual Paulista “Julio de Mesquita Filho” – Faculdade de Ciências Agronômicas/Campus Botucatu-UNESP, no município de Botucatu, SP. O delineamento foi em blocos casualizados com quatro repetições e doze tratamentos, compostos por duas cultivares de mini tomate (Sweet Million e Sweet Grape) e seis relações K:Ca:Mg (4:3:1, 6:3:1, 6:4,5:1, 2,7:3:1, 2,7:2:1, 4:2:1) nas soluções nutritivas. Observou-se que as diferentes relações K:Ca:Mg não influenciaram na produção e nas características de qualidade das diferentes cultivares de mini tomate cultivadas em substrato. Foi verificado aumento da CE da solução do substrato ao longo do ciclo de cultivo. O ICV apresentou tendência crescente ao longo dos ciclos de cultivo, sendo que o índice SPAD variou de 35,8 a 56, 1. Os teores de macro e micronutrientes apresentaram valores semelhantes em ambos os experimentos. A cultivar Sweet Million apresentou maior produção, maior número de frutos, porém a cultivar Sweet Grape apresentou frutos com peso médio maior. A cultivar Sweet Million apresentou maior eficiência no uso da água / Mini tomato has grown in recent years due to increased consumer demand for quality and product diversity. Thus, the management of nutrient solution is a crucial factor for obtaining high yield and quality of the tomato, including the concentrations and the relationships between elements. This study was carried out to evaluate six relationships among K, Ca and Mg on yield and quality in mini tomato grown in substrate, in a greenhouse, in two cropping seasons. The experiments were conducted at the experimental area of the Departamento de Recursos Naturais, Ciência do Solo, Universidade Estadual Paulista “Julio de Mesquita Filho”, Faculdade de Ciências Agronômicas, Campus de Botucatu, em Botucatu, SP. The design was a randomized block design with four replicates and twelve treatments in two tomato cultivars (Sweet Grape and Sweet Million) and six ratios K:Ca:Mg (4:3:1; 6:3:1; 6:4,5:1; 2,7:3:1; 2,7:2:1; 4:2:1) in nutrient solutions. It was observed that the various K: Ca: Mg did not influence the production and quality characteristics of different cultivars of mini tomato grown in substrate. The EC of the solution of the substrate showed an increase during the crop cycle. The ICV showed increasing trend during the crop cycles, and the SPAD index ranged from 35.8 to 56, 1. The contents of macro and micronutrients were very similar in both experiments. Sweet Million cultivar showed higher yield, more fruit, but the Sweet Grape cultivar showed higher average fruit weight. Sweet Million cultivar showed greater efficiency in water use

Orientador: Max José de Araújo Faria Júnior / Banca: Shizuo Seno / Banca: José Luis Susumu Sasaki / Banca: Rerison Catarino da Hora / Banca: Humberto Silva Santos / Resumo: O trabalho teve por objetivo avaliar o efeito da aplicação de diferentes concentrações (0; 50; 100 e 150 mg L-1) de paclobutrazol (PBZ) na produção de mudas, no crescimento, desenvolvimento de plantas, na produção e na qualidade físico-química de dois híbridos de tomateiro (Jennifer e AF 7631), em campo aberto e em ambiente protegido. O trabalho foi desenvolvido de abril a outubro de 2007, na UNESP - Campus de Ilha Solteira, Estado de São Paulo. O PBZ foi aplicado às mudas, aos 15 dias após a germinação. Para avaliação das mudas, foi utilizado delineamento inteiramente casualizado, em esquema fatorial, com 4 repetições e 10 plântulas por parcela. Para avaliação do desenvolvimento e produtividade dos híbridos após transplante, adotou-se o delineamento em blocos casualizados, em esquema fatorial, com análise para grupo de experimentos, modelo fixo, com 4 blocos por ambiente e 9 plantas por parcela. O uso de concentrações crescentes de paclobutrazol reduziu a taxa de crescimento e a altura de plantas, aumentou o diâmetro da haste, reduziu a brotação lateral e reduziu a produtividade da cultura. O PBZ também influenciou significativamente na massa de seca de parte aérea, com aumento linear na massa seca da parte radicular. O híbrido Jennifer apresentou maiores taxas de crescimento absoluto, resultando em plantas com maior altura que o AF 7631, sem que houvesse diferenças entre eles, no que se refere ao diâmetro da haste, brotação lateral e produtividade. Em ambiente protegido, foram obtidas plantas mais vigorosas, com maior altura, brotação lateral e maior produtividade que em campo aberto. O ambiente de cultivo não interferiu em nenhuma das características qualitativas avaliadas, para o híbrido AF 7631, enquanto que, para o Jennifer houve efeito significativo do ambientes de cultivo sobre o teor de sólidos solúveis e acidez titulável... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate the effect of different concentrations (0, 50, 100 and 150 mg L-1) of paclobutrazol (PBZ) on the production of seedlings, plant growth, development, plant yield and physico-chemical quality of fruits, of two tomato hybrids (Jennifer and AF 7631), cultivated in open field and in protected environment. The work was conducted from April to October of 2007, at UNESP - Campus of Ilha Solteira, Sao Paulo State. The PBZ was applied to seedlings, at 15 days after germination. For evaluation of the seedlings, the used statistical experimental design was completely randomized, in factorial outline, with 4 repetitions and 10 seedlings per plot. For evaluation of the development and productivity of two hybrids after transplant it was used a randomized block design, in a factorial array, with analysis for group of experiments, in a fixed model, with 4 replications for environment and 9 plants per plot. The use of increasing concentrations of paclobutrazol reduced the height of plants and their growth rate, increased the stem diameter, decreased the side shooting and reduced the crop yield. PBZ also influenced significantly in the dry shoot, with lineal increase in the dry roots. The hybrid Jennifer showed higher rates of absolute growth, resulting in higher plants than AF 7631, but, with no differences between them, regarding to the stem diameter, to side shooting and crop yield. In the greenhouse, it was obtained higher plants with higher side shooting and higher yield than that observed in the open field. The cultivation environment didn't interfere in none of the appraised qualitative characteristics, for the hybrid AF 7631, while, for Jennifer there was significant effect of the cultivation environment on the contents of soluble solids and titratable acidity, not affecting, however, the maturation index. However of the cultivation... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-08-20T13:25:38Z (GMT). No. of bitstreams: 1 tese_camila_pegoraro.pdf: 3121320 bytes, checksum: 5a704b24078eca8a2b35513ec2a606f6 (MD5) Previous issue date: 2012-09-17 / Abiotic stresses represent large threats to agriculture and food security, since they limit the productivity of the majority of cultivated plants. In order to identify the responses of plants to abiotic stresses and their associations with tolerance under different environmental conditions, concepts and techniques in molecular biology, cell biology and genetics have been used. The identification of genes responsive to stresses can be used to obtain plants tolerant to adverse environmental conditions by genetic transformation or directed crosses. Thus, this study had the objective the establishing of expression profiles of gene belonging to the ERF, HSP, HSF, TIM/TOM and TIC/TOC families in rice and tomato under low O2 stress. Also, the transcriptional profile of peaches under cold stress as obtained. The results indicate that in rice, some members of the ERF family present specific expression according to the stressing agent, while others have overlapping expression among different stresses. Besides, within the ERF family, some genes do present a complex regulation and others a simple regulation. In rice, some genes encode proteins belonging to the TIM/TOM and TIC/TOC complexes present high expression levels 24 hours after anoxia stress. However, after 72 hours under anoxia, the majority of genes were inhibited, suggesting an interruption on the transport of proteins to the mitochondria and chloroplast during the stress period. When the HSP expression profiles of flooding tolerant and sensitive rice cultivars were compared, transcript accumulation occurred for both cultivar types. However, the majority of genes evaluated were more responsive in the sensitive cultivar than in the tolerant, indicating that HSPs have an important association in the response to anoxia stress but are not directly involved in the tolerance. In tomato fruits stored under hypoxia, two sHSPs genes were highly induced by low oxygen levels, indicating a primary action of these genes on keeping cell homeostasis after the stress. In peaches, the application of gibberellic acid acts on preventing the damaged caused by cold by the induction of genes associated to lipid metabolism, cell wall degradation and trehalose synthesis. / Estresses ambientais representam grandes ameaças à agricultura e, por consequência, à segurança alimentar, uma vez que limitam a produtividade da maioria das plantas cultivadas. Buscando identificar as respostas das plantas frente a estresses abióticos e suas relações com a tolerância sob diferentes condições ambientais, conceitos e técnicas de biologia molecular, biologia celular e genética vêm sendo continuamente utilizadas. A identificação de genes responsivos a estresses pode ser utilizada na obtenção de plantas tolerantes a condições ambientais adversas através de manipulação genética ou cruzamentos direcionados entre diferentes genótipos. Desta forma, este estudo teve como objetivo estabelecer o perfil de expressão de genes pertencentes às famílias ERF, HSP, HSF, TIM/TOM e TIC/TOC, em arroz e tomate sob condições de estresse por deficiência de O2. Além disso, buscou-se estabelecer o perfil transcricional de pêssegos sob condição de estresse por frio. Os resultados obtidos demonstram que em arroz, alguns membros da família ERF apresentam expressão específica de acordo com o agente estressor, enquanto que outros apresentam sobreposição de expressão entre os estresses, além disso, dentro da família ERF alguns genes apresentam regulação complexa e outros regulação simples. Em arroz, alguns genes codificadores de proteínas pertencentes aos complexos TIM/TOM e TIC/TOC apresentaram altos níveis de expressão 24 horas após estresse por anoxia. Entretanto, após 72 horas sob condições de anoxia, ocorreu a inibição da expressão da maioria dos genes pertencentes a estes complexos, sugerindo que possa haver uma interrupção no transporte de proteínas para a mitocôndria e cloroplasto durante este período de estresse. Ao comparar cultivares de arroz tolerante e sensível ao alagamento, verificou-se que houve um acúmulo de transcritos dos genes codificadores de HSPs em ambas as cultivares. Entretanto, a maioria dos genes avaliados foi mais responsiva ao estresse por anoxia na cultivar sensível, do que na cultivar tolerante, sugerindo que genes HSPs têm relação importante na resposta ao estresse por anoxia, mas não estão diretamente envolvidos na tolerância. Em frutos de tomate armazenados sob hipoxia dois genes codificadores de sHSPs foram altamente induzidos por baixos níveis de oxigênio, indicando uma ação primária destes genes na manutenção da homeostase celular após este estresse. Em pêssegos, a aplicação de ácido giberélico atua na prevenção de danos ocasionados pelo frio através da indução de genes associados ao metabolismo de lipídios, à degradação da parede celular e à síntese de trealose.

Agriculture uses several options to increase and conservation of the yields. The tomato cultivation is a typically traditional and fragile crop in which is used many synthetic products that cause damages to both environment and human health. To minimize the use of these products some mechanisms are adopted such as pollination. The variety of pollinators depend on the flower structure, in the case of S. lycopersicum., as other solanaceaes, and it is need flower vibration for the pollen drop. This vibration and the exclusive production of pollen determine the type of visitant of tomato flowers. To aim knowing the pollinators of tomato flowers, the differences between traditional and organic cultivation and the associated vegetation, it was collected visitant insects between March and November 2008 in the municipality of Itabaiana and Areia Branca, Sergipe state. It was collected 327 insects belonging to five orders. The Hymenoptera Order was the dominant taxon in which effective pollinators through buzz pollination was observed. Other visitants were considered as non-effective because they did not perform the buzz vibration; some causes damages the flowers during food searching. Among hymenopterans it was found: Anthophoridae; Apidae; Chalcididae; Eumeninae; Formicidae; Scollidae; Sphecidae; Halictidae; Vespidae; Coleopteras: Chrysomelidae, Carabidae e Coccinelidae. Among the Diptera Order: Ascilidae, Bibionidae, Syrphidae, Muscidae e Tabanidae. The representant of the Lepidoptera Order: Licaenidae, Nymphalidae e Papilonidae. The insect families of the Orthoptera Order were: Romaleidae e Tettigonidae, and Hemiptera Order were: Pentatomidae, Scutelaridae e Coreidae. The associated surrounding vegetation was respectively characterized the planting of other species (mostly coriander) or gramineae in traditional and organic tomato crops. The abundance and diversity of insect visitants in organic crops was greater than the higher in traditional crops. / A agricultura utiliza várias opções para o aumento e conservação da produção e redução das perdas. A cultura do tomateiro, por sua fragilidade, é realizada com base em muitos produtos sintéticos, que causam prejuízos ao meio ambiente e à saúde humana. Para minimizar o uso destes produtos durante a produção, alguns mecanismos são empregados, como a polinização, realizada de forma programada ou natural. A variedade de polinizadores depende da estrutura floral, no caso de S. lycopersicum, como nas demais solanáceas, é necessária a vibração das flores para a liberação do pólen. Essa vibração e a exclusiva produção de pólen determinam o tipo de visitante dos tomateiros. Objetivando conhecer os polinizadores, as diferenciações entre os cultivos orgânicos e tradicionais, e a vegetação associada as plantações foram realizadas coletas dos visitantes florais e da vegetação entre os meses de março e novembro de 2008, em propriedades agrícolas das cidades de Itabaiana e Areia Branca Sergipe. Foram coletados 327 insetos de cinco ordens, sendo Hymenoptera o grupo dominante, onde estão os polinizadores efetivos das flores do tomate, que são abelhas capazes de realizar a vibração chamada buzz pollination. Os outros visitantes se aproximam dos cultivos em busca de alimentos, mas não realizam esse movimento, logo não são considerados polinizadores eficazes, alguns até destroem as flores na busca pelo alimento. Dentre os himenópteros estão as famílias: Anthophoridae; Apidae; Chalcididae; Eumeninae; Formicidae; Scollidae; Sphecidae; Halictidae; Vespidae; coleópteros: Chrysomelidae, Cara bidae e Coccinelidae; dípteros: Ascilidae, Bibionidae, Syrphidae, Muscidae e Tabanidae; lepidópteos: Licaenidae, Nymphalidae e Papilonidae; ortópteros: Romaleidae e Tettigonidae; hemípteros: Pentatomidae, Scutelaridae e Coreidae. Já na vegetação coletada no entorno dos cultivos de tomate ou foram encontrados outros cultivos como a produção de coentro muito comum na região, ou prevaleceram algumas gramíneas, sendo maior a variedade nas orgânicas. Quanto à diferenciação em relação aos insetos é observada uma maior abundância e diversidade de visitantes nas propriedades orgânicas do que nas tradicionais.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-09-14T18:11:08Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) UNIVERSIDADE FEDERAL DE PELOTAS - TESE.pdf: 3121320 bytes, checksum: 5a704b24078eca8a2b35513ec2a606f6 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2016-09-15T19:42:11Z (GMT) No. of bitstreams: 2 UNIVERSIDADE FEDERAL DE PELOTAS - TESE.pdf: 3121320 bytes, checksum: 5a704b24078eca8a2b35513ec2a606f6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-15T19:42:11Z (GMT). No. of bitstreams: 2 UNIVERSIDADE FEDERAL DE PELOTAS - TESE.pdf: 3121320 bytes, checksum: 5a704b24078eca8a2b35513ec2a606f6 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2012-09-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Estresses ambientais representam grandes ameaças à agricultura e, por consequência, à segurança alimentar, uma vez que limitam a produtividade da maioria das plantas cultivadas. Buscando identificar as respostas das plantas frente a estresses abióticos e suas relações com a tolerância sob diferentes condições ambientais, conceitos e técnicas de biologia molecular, biologia celular e genética vêm sendo continuamente utilizadas. A identificação de genes responsivos a estresses pode ser utilizada na obtenção de plantas tolerantes a condições ambientais adversas através de manipulação genética ou cruzamentos direcionados entre diferentes genótipos. Desta forma, este estudo teve como objetivo estabelecer o perfil de expressão de genes pertencentes às famílias ERF, HSP, HSF, TIM/TOM e TIC/TOC, em arroz e tomate sob condições de estresse por deficiência de O2. Além disso, buscou-se estabelecer o perfil transcricional de pêssegos sob condição de estresse por frio. Os resultados obtidos demonstram que em arroz, alguns membros da família ERF apresentam expressão específica de acordo com o agente estressor, enquanto que outros apresentam sobreposição de expressão entre os estresses, além disso, dentro da família ERF alguns genes apresentam regulação complexa e outros regulação simples. Em arroz, alguns genes codificadores de proteínas pertencentes aos complexos TIM/TOM e TIC/TOC apresentaram altos níveis de expressão 24 horas após estresse por anoxia. Entretanto, após 72 horas sob condições de anoxia, ocorreu a inibição da expressão da maioria dos genes pertencentes a estes complexos, sugerindo que possa haver uma interrupção no transporte de proteínas para a mitocôndria e cloroplasto durante este período de estresse. Ao comparar cultivares de arroz tolerante e sensível ao alagamento, verificou-se que houve um acúmulo de transcritos dos genes codificadores de HSPs em ambas as cultivares. Entretanto, a maioria dos genes avaliados foi mais responsiva ao estresse por anoxia na cultivar sensível, do que na cultivar tolerante, sugerindo que genes HSPs têm relação importante na resposta ao estresse por anoxia, mas não estão diretamente envolvidos na tolerância. Em frutos de tomate armazenados sob hipoxia dois genes codificadores de sHSPs foram altamente induzidos por baixos níveis de oxigênio, indicando uma ação primária destes genes na manutenção da homeostase celular após este estresse. Em pêssegos, a aplicação de ácido giberélico atua na prevenção de danos ocasionados pelo frio através da indução de genes associados ao metabolismo de lipídios, à degradação da parede celular e à síntese de trealose. / Abiotic stresses represent large threats to agriculture and food security, since they limit the productivity of the majority of cultivated plants. In order to identify the responses of plants to abiotic stresses and their associations with tolerance under different environmental conditions, concepts and techniques in molecular biology, cell biology and genetics have been used. The identification of genes responsive to stresses can be used to obtain plants tolerant to adverse environmental conditions by genetic transformation or directed crosses. Thus, this study had the objective the establishing of expression profiles of gene belonging to the ERF, HSP, HSF, TIM/TOM and TIC/TOC families in rice and tomato under low O2 stress. Also, the transcriptional profile of peaches under cold stress as obtained. The results indicate that in rice, some members of the ERF family present specific expression according to the stressing agent, while others have overlapping expression among different stresses. Besides, within the ERF family, some genes do present a complex regulation and others a simple regulation. In rice, some genes encode proteins belonging to the TIM/TOM and TIC/TOC complexes present high expression levels 24 hours after anoxia stress. However, after 72 hours under anoxia, the majority of genes were inhibited, suggesting an interruption on the transport of proteins to the mitochondria and chloroplast during the stress period. When the HSP expression profiles of flooding tolerant and sensitive rice cultivars were compared, transcript accumulation occurred for both cultivar types. However, the majority of genes evaluated were more responsive in the sensitive cultivar than in the tolerant, indicating that HSPs have an important association in the response to anoxia stress but are not directly involved in the tolerance. In tomato fruits stored under hypoxia, two sHSPs genes were highly induced by low oxygen levels, indicating a primary action of these genes on keeping cell homeostasis after the stress. In peaches, the application of gibberellic acid acts on preventing the damaged caused by cold by the induction of genes associated to lipid metabolism, cell wall degradation and trehalose synthesis.

Orientador: Elizabeth Orika Ono / Resumo: O objetivo do trabalho foi avaliar os efeitos fisiológicos, bioquímicos e produtivos em plantas de tomateiro, além dos atributos de qualidade de frutos com a aplicação foliar da mistura de micronutrientes e reguladores vegetais em diferentes doses e períodos de desenvolvimento da cultura em condições de cultivo protegido. Para isso foram instalados dois experimentos independentes, em delineamento de blocos ao acaso com oito tratamentos e três repetições. O material genético utilizado foi o híbrido Santy e os tratamentos utilizados foram: T1- Controle; T2 - IBA + GA3 + Kt - 0,5 L ha-1; T3 (Co + Mo - 0,5 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1); T4 - (Co + Mo - 1 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1); T5 (Co + Mo - 2 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1); T6 (Co + Mo - 0,5 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1); T7 - (Co + Mo - 1 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1) e T8 (Co + Mo - 2 L ha-1) + (IBA + GA3 + Kt - 0,5 L ha-1). As aplicações dos tratamentos 3, 4 e 5 iniciaram-se no florescimento e cessaram na primeira colheita dos frutos, enquanto os tratamentos 2, 6, 7 e 8 as aplicações tiveram início no florescimento e transcorreram até a última colheita, com intervalos de 14 dias entre as aplicações. No capítulo 1 foram determinadas atividade enzimática antioxidativa, peroxidação lipídica, peróxido de hidrogênio, medidas de trocas gasosas, fluorescência da clorofila a e parâmetros de produtividade: produção total, comercial e não comercial, massa média de frutos comerciai... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this research was to evaluate the physiological, biochemical and productive effects on tomato crop. Moreover, it was study fruit quality attributes with the foliar application of the mixture of micronutrients and crop regulators in different doses and periods of development under protected conditions. . For this, two independent experiments were installed, in a randomized block design with eight treatments and three replications. The genetic material used was the hybrid Santy and the treatments used were: T1- Control; T2 - IBA + GA3 + Kt - 0.5 L ha-1; T3 (Co + Mo - 0.5 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1); T4 - (Co + Mo - 1 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1); T5 (Co + Mo - 2 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1); T6 (Co + Mo - 0.5 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1); T7 - (Co + Mo - 1 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1) and T8 (Co + Mo - 2 L ha-1) + (IBA + GA3 + Kt - 0.5 L ha-1). In treatments 3, 4 and 5, the applications started at flowering and stopped at the first harvest of fruits, while treatments 2, 6, 7 and 8 the applications started at flowering and it gone until the last harvest, with intervals of 14 days between applications. In the first chapter, they were determined antioxidative enzyme activity, lipid peroxidation, hydrogen peroxide, gas exchange measures, chlorophyll fluorescence and productivity parameters, total, commercial and non-commercial production, average mass of commercial fruits, number of total fruits, commercial an... (Complete abstract click electronic access below) / Doutor

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Thesis(Ph.D. Agriculture (Soil Science)) -- University of Limpopo, 2020 / Due to high incidents of drought in the semi-arid regions of Limpopo Province, South Africa, the potential feasibility of using treated wastewater for irrigating vegetable crops had been researched and developed under the best practices of Natuurboerdery farming system. The investigation aimed at the development of soil and plant health management strategies for crops irrigated with treated wastewater that could ameliorate the ever-increasing demand for fresh irrigation water in the Province. Seven specific objectives, reduced to three overall objectives under Natuurboedery farming system were intended to investigate (1) the chemical and biological quality of treated wastewater used in irrigation with respect to disposal points and sampling period, (2) the responses of soil physico-chemical properties, heavy metal distribution and biological-soil-health indicators to irrigation with treated wastewater under field conditions and (3) the partitioning of cations and heavy metals in root, stem and leaf tissues of onion, tomato and a selected weed plant irrigated with treated wastewater. In each objective, unless otherwise stated, treatment effects were described at the probability level of 5%. In Objective 1, relative to the borehole water, treated wastewater had lower concentration of Ca, Mg, K, Na, Cl, HCO3 - , SO4 - , Zn, Cr and Pb, with temporal and spatial tendencies in accumulation of certain elements. In contrast, the treated wastewater had higher loads of pathogenic microbes that included bacteria (Escherichia coli, Salmonella spp., Shigella spp. and Vibrio spp.), protozoa (Entamoeba histolytica) and two helminths (Schistosoma mansoni; Ascaris lumbricoides), with temporal and spatial tendencies. In Objective 2, Al and Cr tended to be high in deeper soil layers (60-100 cm), whereas most essential nutrient elements and essential heavy metals (Cu, Fe, Mn, Ni, Zn, As, Cr and Pb) were contained in the upper soil levels (0-40 cm). The upper soil levels were also characterised by having substantial attributes of root health, namely, soil organic carbon, active carbon and potentially mineralisable nitrogen. In Objective 3, root, stem and leaf tissues of horseweed (Conyza canadensis L.), onion (Allium cepa L.) and tomato (Solanum lycopersicum L.) plants had different accumulation abilities for different metals, except for As. Contrary to the expectation, the onion bulb contained less test cations and heavy metals. In conclusion, in terms of chemical component at the time of sampling, as depicted from the water and soil samples, the treated wastewater was suitable for irrigation. However, in terms of pathogenic microbes, the treated wastewater was not suitable for irrigating crops intended for human consumption due to significantly higher loads than the permissible standards. Amongst all observed challenges, the reduction of pathogenic microbes should be given priority since it contravened existing national and international standards for using treated wastewater for in irrigation of crops intended for human consumption. / National Research Foundation (NRF)

Tomato is an important food crop and a model for fleshy fruit development. The process of fruit ripening involves changes in chemical composition and in particular the accumulation of sugars, organic, amino acids and carotenes. The research described in this thesis aimed to identify key regulatory aspects associated with the accumulation of the major acids in tomato fruit by analysis of introgression lines resulting from a cross between a cultivated variety, Solanum lycopersicum, and a wild progenitor species, Solanum pennellii. Line 2-5 showed increases in citrate, malate, aspartate and glutamate in fruit grown under greenhouse conditions. The genetic differences between line 2-5, its overlapping lines, sub-introgression lines and the recurrent parent were used to link the metabolite phenotypes to smaller chromosomal regions. This analysis suggested multiple epistatic loci control fruit metabolite accumulation. Investigation of the biochemical differences between line 2-5 and the recurrent parent revealed that organic and amino acid accumulation did not dependent upon increased TCA cycle capacity. Regulation at the metabolic level was identified for citrate accumulation with changes in cytosolic aconitase in line 2-5. As these metabolites accumulate in the vacuole, tonoplast transport was investigated. Correlation of ATPase-dependent malate influx with altered malate content suggested malate tonoplast transport plays a role in malate accumulation and highlights the importance of vacuolar storage and transport in the regulation of organic and amino acid accumulation.