Reducing disease and increasing fruit quality in vigorous vineyards with dense canopies is demanding of time and resources; unfortunately, vineyards of this nature are common in humid environments. This study investigated the effectiveness with which vine capacity and water status could be regulated as well as if they related to fruit quality and wine sensory perception. The treatments regulating vine size and water status were under-trellis groundcover, root manipulation, rootstocks, and irrigation. Treatments were arranged in a strip-split-split plot design before the introduction of the irrigation treatment resulted in incomplete replication in each block. Treatment levels were under-trellis cover crop (CC) compared to under-trellis herbicide (Herb); root restriction bags (RBG) compared to no root manipulation (NRM); three compared rootstocks (101-14, 420-A, riparia Gloire); low water stress (LOW) compared to high water stress (HIGH). Vines grown with RBG and CC regulated vegetative growth more so than conventional treatments, resulting in 56% and 23% greater cluster exposure flux availability (CEFA). High water stress (HIGH) and RBG reduced stem water potential and discriminated less against 13C. Vines grown with RBG and CC consistently reduced harvest berry weight by 17 and 6% compared to conventional treatments. Estimated phenolics were consistently increased by RBG and were correlated with berry weight, vine capacity and CEFA. Sensory attributes were significantly distinguishable between wines produced from vines that differed in both vine capacity and water status, amongst other responses. Treatments have been identified that can alter the sensory perception of wines, with the potential to improve wine quality. / Master of Science

La sélection naturelle constitue un processus clé de l’adaptation des populations à leur environnement, favorisant les variants présentant les meilleures valeurs sélectives. Les champignons présentent généralement des traits biologiques (diversité des modes de reproduction, grandes tailles de populations, fortes capacités de dispersion, entre autres) qui favorisent leur adaptation à des environnements variés. La compréhension des mécanismes qui sous-tendent l’évolution de leurs populations sous les contraintes, naturelles et anthropiques, qu’elles subissent constituent donc un enjeu majeur pour la protection des plantes, en particulier dans le contexte actuel de durabilité des méthodes de lutte. Dans cette thèse, nous avons décrit la structure et la diversité des populations Botrytis cinerea à l’aide de marqueurs neutres et sélectionnés et d’un échantillonnage emboîté, et avons proposé des mécanismes pouvant expliquer les résultats observés. Puis nous avons analysé la réponse adaptative des populations de B. cinerea en Champagne, aux applications de fongicides. Premièrement, nous avons montré que la pourriture grise était causée par un complexe de deux espèces cryptiques, vivant en sympatrie sur des hôtes communs. De plus, les populations françaises de B. cinerea sont structurées en cinq dèmes, caractérisés par le système de culture (sélection directionnelle), la plante-hôte (adaptation écologique), et dans une moindre mesure, par la géographie. Sur vigne, nous avons mis en évidence une entité dont l’isolement génétique semble lié à un isolement temporel. Par ailleurs, nous avons montré que l’application de fongicides conduit à la sélection de phénotypes résistants spécifiquement à quasiment tous les modes d’action homologués, selon des proportions variant suivant les vignobles et les usages. Plus particulièrement, la résistance aux fongicides inhibiteurs de la succinate déshydrogénase (SDHI) est causée par au moins sept mutations affectant les gènes encodant la protéine cible de ces fongicides, déterminant ainsi une grande variété de phénotypes. Enfin, nous avons montré que les fongicides ne modifiaient pas la structure neutre des populations mais qu’ils pouvaient conduire à une perte de richesse allélique dans les populations traitées ainsi qu’à un équilibre sélection-migration détectable dans certaines situations sous forme de clines au loci sous pression de sélection contemporaine tels que ceux déterminant la résistance multidrogues. La modélisation de l’évolution des fréquences de résistance hivernale a permis d’estimer le coût de la résistance pour quatre loci déterminant la résistance aux fongicides. Cette thèse a permis d’appréhender le fonctionnement des populations de B. cinerea et de comprendre et quantifier partiellement les mécanismes sélectifs opérant in natura. Ces informations seront utilisées pour raisonner des stratégies anti-résistance adaptées localement et durables. / Natural selection is the most powerful force driving population adaptation to their environment, favoring the variants with the best fitness. Fungi generally exhibit biological traits (diversity of reproduction modes, large population sizes, and intense dispersion) that favor their adaptation to changing environments. Therefore, disentangling the mechanisms that explain their evolution under natural and anthropic constraints constitute a major challenge for plant protection, especially in the actual context of agriculture sustainability. In this thesis, we described Botrytis cinerea population structure and diversity, using neutral and selected markers and a hierarchical sampling, and proposed mechanisms that may explain these observations. We then analyzed the adaptive answer of this species towards fungicide applications. First, we showed that grey mold populations were caused by a complex of two cryptic species, living sympatrically on the same hosts. Second, B. cinerea populations are divided into five demes, according to the cropping system (directional selection), the host-plant (ecological adaptation), and to a lesser extent, by geography. On grapevine, we identified a specific populations exhibiting temporal isolation, as an evidence of extreme exploration of the viticultural conditions. Moreover, fungicide applications select resistance towards all unisite modes of action, with few exceptions, but at varying proportions according to vineyards and fungicide use. More specifically, resistance to succinate dehydrogenase inhibitors (SDHIs) is caused by at least seven mutations altering the target genes of these fungicides, and determines a large variety of phenotypes in the field. At last, we showed that fungicides did not shape population structure but that they could decrease allele richness in treated areas and lead to migration-selection equilibrium, detectable in some situation and for loci under contemporary selective pressures as clines. Modeling the evolution of resistance during winter allowed estimating fitness cost of four loci involved in contemporary fungicide resistance, such as multidrug resistance. As a conclusion, this thesis helped to understand how B. cinerea populations evolve and to detect and quantify selective mechanisms at work in natura. This information will be useful to deign sustainable and locally-adapted anti-resistance strategies.

The use of entomopathogenic fungi to control agriculturally important pests, both in greenhouses and in the field, has been demonstrated by various authors for a number of years. This has been brought about by the development of resistance in certain pest species to chemical applications and a growing public awareness of the safety implications of residual insecticides. Several entomopathogenic fungi were tested against four insect pests found in the Republic of South Africa (RSA), the greenhouse whitefly, Trialeurodes vaporariorum, the rice weevil, Sitophilus oryzae, the grapevine mealybug, Planococcusficus and the sugarcane stem borer, Eldana saccharina. Further concentration, temperature and humidity studies were conducted with selected isolates on the rice weevil, S. oryzae. Sitophilus oryzae is considered one ofthe most important pests of stored grain. Several fungal isolates were tested against the rice weevil, four of which, B1, PPRI 6690, PPRI 6864 and PPRI 7067, were selected for further testing based on the mortality results over a 21 d period. Varying conidial concentrations were applied and at high doses of 1x10 -6 conidia ml -1 with mortality rates of to 84% achieved. LT 50 values ranged from 6 - 68d. Increased spore concentration resulted in an increase in overall mortality. Temperature and humidity was found to affect the infection potential of the four isolates tested. Four temperatures ranging from 15 - 30°C were tested. The highest mortality rates were obtained at 25°C where mortality ranged from 46 - 65% in 14d. Mortality rates decreased with decreasing temperature, and no mortality was recorded at 30°C. Temperature was found to significantly alter the LT 50 values, increasing the LT 50 with decreasing temperatures. Decreasing the humidity resulted in an increased LT 50 and a reduction in the overall mortality rates. The mortality of S. oryzae ranged according to the RH and isolate. Isolates Bland PPRI 6690 resulted in the highest mortalities of 80 and 83% at 92.5% RH, with LT 50's of 6.3d and 6.4d, respectively. Several entomopathogenic fungi were tested against T vaporariorum, P. ficus and E. saccharina, three key pests of South African crops. Nine fungal isolates were tested against the greenhouse whitefly, T vaporariorum, with mortalities ranging from 26.7 - 74.7% over 14d. Beauveria bassiana Isolates Bl and PPRl 6690 produced the highest mortality rates and were recommended for further pathogenicity testing against T. vaporariorum. Planococcus ficus is a common pest ofvineyards in the Western Cape Province, South Africa. Nine entomopathogenic fungi were screened against P.ficus, only two of which produced mortality. Eldana saccharina is a stalk borer, which infests sugarcane in large areas of Southern Africa. Five isolates were tested against second and third instar larvae, three of which, B1, PPRl 6864 and PPRl 6690 resulted in mortalities. Mean percentage mortality was low for all three isolates. From the study it was evident that two of the isolates tested, Bland PPRI 6690 (B. bassiana), showed potential against three of the four pests, and two isolates of Lecanicillium lecanii caused mortality in P. ficus. Further research and understanding of the effect of environmental conditions, spore concentration and epizootic potential would result in the further development of these isolates as future biological control agents. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

No description available.

[ES] Las plantas de vid (Vitis vinifera L.) están expuestas a una gran variedad de patógenos. En la actualidad, las enfermedades fúngicas de la madera de la vid (GTDs) se encuentran entre los principales factores que limitan la productividad de este cultivo. Una vez las vides están infectadas, la productividad de la planta disminuye, provocando una muerte lenta o apoplética. La investigación de agentes de control biológico (BCAs) capaces de prevenir, o al menos minimizar, el impacto de las GTDs, se considera una prioridad de investigación. En esta Tesis Doctoral se caracterizó un agente de biocontrol potencial y, junto con un producto comercial biológico ya registrado, fueron probados contra varios patógenos agentes causales de GTDs, en invernadero bajo condiciones controladas, y también durante el proceso de propagación de la vid en vivero. Los resultados del análisis genómico completo de Bacillus subtilis PTA-271 muestran un sistema funcional de motilidad de enjambre, una fuerte capacidad de supervivencia y un conjunto de genes que codifican sustancias bioactivas conocidas por estimular el crecimiento o las defensas de las plantas, influir en la microbiota beneficiosa y contrarrestar la agresividad de los patógenos. Cuando Bs PTA-271 se probó contra Neofusicoccum parvum BT67 en plantas injertadas de invernadero, Bs PTA-271 y Ta SC1 demostraron que el cultivar contribuye a los efectos beneficiosos de Bs PTA-271 y Ta SC1 contra Np-Bt67. La aplicación simultánea de ambos BCAs demostró ser beneficiosa contra este patógeno en vides del cultivar Tempranillo. El análisis transcriptómico de las mismas muestras mostró ampliamente los cambios en la fisiología de la planta inducidos tanto por Bs PTA-271 como por Ta SC1 para proteger la vid ante la infección por Np-Bt67. En Chardonnay, las plantas infectadas con Np-Bt67 presentan genes sobreexpresados que están implicados en las vías de señalización del acido absicico (ABA). En Tempranillo, la infección con Np-Bt67 provoca cambios de expresión en más de 200 genes, relacionados sobre todo con la importación de aminoácidos, procesos relacionados con el cloroplasto y el fotosistema, respuestas de la planta a estímulos bióticos y biosíntesis de metabolitos secundarios. La protección de Ta SC1 en las plantas de Tempranilllo implica un mayor número de cambios, que abarcan tanto el metabolismo primario como el secundario, relacionados con cambios en las señales hormonales, como con el aicdo absicico (ABA). Durante el proceso de producción de la vid en vivero, los resultados demostraron una reducción significativa del porcentaje de plantas infectadas con los patógenos asociados a las enfermedades de decaimiento por Botryosphaeria y Pie negro en el material de vivero tratado con Ta SC1 y Bs PTA-271 respectivamente. Los tratamientos simultáneos con ambos BCAs presentaron una reducción en el porcentaje de plantas infectadas con ambos tipos de patógenos. Al probar el efecto de Bs PTA-271 y Ta SC1 en el microbioma de la rizosfera de la vid de dos suelos diferentes infectados con patógenos del pie negro, los resultados muestran que la inoculación de los BCAs parece mejorar las redes del microbioma de la rizosfera y el estado de saneamiento, sin embargo, el efecto beneficioso de los BCAs puede ser dependiente del suelo. En general, este estudio aportó nuevos conocimientos sobre el uso de uno o más BCAs contra varios patógenos asociados a las GTDs, tanto en el vivero como en vides adultas (viñedo). Además, se destacó el modo de acción de ambos BCAs en la protección de la vid. Por lo tanto, estos hallazgos proporcionan, no sólo una mejor comprensión de las interacciones entre los BCAs, la vid y los patógenos, sino que también son una fuerte contribución a una estrategia de gestión sostenible de las GTDs. / [CA] Les plantes de vinya (Vitis vinifera L.) estan exposades a una gran varietat de patògens. En l'actualitat, les malalties fúngiques de la fusta de la vinya (GTDs) es troben entre els principals factors que limiten la productivitat d'aquest cultiu. Una vegada les vinyes estan infectades, la productivitat de la planta disminueix, provocant una mort lenta o apoplética. La investigació d'agents de control biològic (BCAs) capaços de previndre, o almenys minimitzar, l'impacte de les GTDs, es considera una prioritat d'investigació. En aquesta Tesi Doctoral es va caracteritzar en profunditat un agent de biocontrol potencial i, juntament amb un producte comercial biològic ja registrat, tots dos BCAs van ser provats contra diversos patògens agents causals de GTDs, en hivernacle sota condicions controlades, i també durant el procés de propagació de la vinya en viver. Els resultats de l'anàlisi genòmica completa de Bs PTA-271 mostren un sistema funcional de motilitat d'eixam, una forta capacitat de supervivència i un conjunt de gens que codifiquen substàncies bioactivas conegudes per estimular el creixement o les defenses de les plantes, influir en la microbiota beneficiosa i contrarestar l'agressivitat dels patògens. Quan Bs PTA-271 es va provar contra Np BT67 en plantes empeltades d'hivernacle, Bs PTA-271 i Ta SC1 van demostrar que la cultivar contribueix als efectes beneficiosos de Bs PTA-271 i Ta SC1 contra Np-Bt67. L'aplicació simultània de tots dos BCAs va demostrar ser beneficiosa contra aquest patogen en vinyes del cultivar Ull de llebre. L'anàlisi transcriptómico de les mateixes mostres va mostrar àmpliament els canvis en la fisiologia de la planta induïts tant per Bs PTA-271 com per Ta SC1 per a protegir la vinya davant la infecció per Np-Bt67. En Chardonnay, les plantes infectades amb Np-Bt67 presenten gens sobreexpresados que estan implicats en les vies de senyalització de l'acidifique absicico (ABA). En Ull de llebre, la infecció amb Np-Bt67 provoca canvis d'expressió en més de 200 gens, relacionats sobretot amb la importació d'aminoàcids, processos relacionats amb el cloroplast i el fotosistema, respostes de la planta a estímuls biòtics i biosíntesis de metabòlits secundaris. La protecció de Bs PTA-271 en Chardonnay implica gens relacionats amb la biosíntesi d'ABA, les vies dels fenilpropanoides, els metabòlits secundaris, i l'estructura i organització de la paret cellular. La protecció de Ta SC1 en les plantes de Tempranilllo implica un major nombre de canvis, que abasten tant el metabolisme primari com el secundari, relacionats amb canvis en els senyals hormonals, com amb l'acid abcísic (ABA). Durant el procés de producció de la vinya en viver, els resultats van demostrar una reducció significativa del percentatge de plantes infectades amb els patògens associats a les malalties de decaïment per Botryosphaeria i Peu negre en el material de viver tractat amb Ta SC1 i Bs PTA-271 respectivament. Els tractaments simultanis amb tots dos BCAs van presentar una reducció en el percentatge de plantes infectades amb tots dos tipus de patògens. En provar l'efecte de Bs PTA-271 i Ta SC1 en el microbioma de la rizosfera de la vinya de dos sòls diferents infectats amb patògens del Peu negre, els resultats mostren que la inoculació dels BCAs sembla millorar les xarxes del microbioma de la rizosfera i l'estat de sanejament, no obstant això, l'efecte beneficiós dels BCAs pot ser dependent del sòl. En general, aquest estudi va aportar nous coneixements sobre l'ús d'un o més BCAs contra diversos patògens associats a les GTDs, tant en el viver com en vinyes adultes. A més, es va destacar la manera d'acció de tots dos BCAs en la protecció de la vinya. Per tant, aquestes troballes proporcionen, no sols una millor comprensió de les interaccions entre els BCAs, la vinya i els patògens, sinó que també són una forta contribució a una estratègia de gestió sostenible de les GTDs. / [EN] Grapevine (Vitis vinifera L.) plants are exposed to a wide variety of pathogens. Nowadays, grapevine fungal trunk diseases (GTDs) are amongst the main constraints for the productivity of this crop. Once infected, plant productivity is decreased, leading to a plant slow or apoplectic death. Investigation of biocontrol agents (BCAs) capable to forestall or at least to minimize the impact of GTDs, while being a sustainable treatment, is viewed as a research priority. One potential BCA was deeply characterized, and together with a biological commercial product, both BCAs were tested against several GTD pathogens, in greenhouse under controlled conditions, and during the grapevine propagation process. Results from the full genomic analysis of Bacillus subtilis PTA-271 (as BCA with a potential) show a functional swarming motility system, strong survival capacities and a set of genes encoding for bioactive substances known to stimulate plant growth or defenses, influence beneficial microbiota, and counteract pathogen aggressiveness. When tested against Neofusicoccum parvum Bt67 (thereafter Np-Bt67) in greenhouse cuttings, B. subtilis PTA-271 (Bs PTA-271) and T. atroviride SC1 (Ta SC1) proved that the cultivar contributes to their beneficial effects against Np-Bt67. The simultaneous application of both BCAs was further proved to be even more effective to protect Tempranillo cuttings. Moreover, the transcriptomic analysis from the same samples showed extensively the plant physiology changes induced by the pathogen but also by each BCA, Bs PTA-271 on Chardonnay and Ta SC1 on Tempranillo, to protect grapevine from Np-Bt67 infection. Thus, Chardonnay cuttings infected with Np-Bt67 showed overexpressed genes implicated on abscisic acid (ABA) biosynthesis and signaling pathways. In Tempranillo, the infection with Np-Bt67 leads to more substantial changes in gene expression, related mostly with amino acid import, chloroplast and photosystem related processes, plant responses to biotic stimulus, and biosynthesis of secondary metabolites. Protection induced by Bs PTA-271 in Chardonnay targets genes related to ABA biosynthesis, phenylpropanoid pathways and secondary metabolites, and cell wall structure/organization in relationship with carbohydrate metabolism that requires much more consideration. Protection with Ta SC1 in Tempranilllo requires a larger number of changes related to transporters, cell wall integrity and extension, cell division and pathogen induced cell death, multidirectional active proteins, and microbiome interactions. During the grapevine nursery process, the results demonstrated a significant reduction on the percentage of infected plants with Botryosphaeria dieback and Black-foot pathogens in the material treated with Ta SC1 and Bs PTA-271 respectively. The simultaneous treatments with both BCAs presented a reduction on infected plants with both Botryosphaeria dieback and Black foot pathogens. When testing the effect of Bs PTA- 271 and Ta SC1 in grapevine rhizosphere microbiome of two different soil infected with Black foot pathogens, results show that the inoculation of BCAs seems to improve the rhizosphere microbiome networks and sanitation status, however, the beneficial effect of BCAs can be soil-dependent. Moreover, as observed in the other experiments, the combination of both BCAs improves their beneficial effect in the rhizosphere microbiome. Overall, this study brought new insights on the use of one or more BCAs against several GTD pathogens, from nursery to adult grapevines. Moreover, highlighted both BCAs mode of action in grapevine protection. Thus, these findings provide, not only a better understanding of BCAs, grapevine, and pathogens interactions, but are also a strong contribution for the future development of sustainable GTDs management strategies. / Cunha Maia Leal, CD. (2022). Sustainable Management of Grapevine Trunk Diseases in Vineyard: Deliver Biocontrol Agents and Associated Molecules [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191261

La ricerca analizza l’evoluzione della vitivinicoltura nell’Oltrepò Pavese quale elemento caratterizzante il paesaggio di questo territorio. Tale settore produttivo risulta essere una delle principali attività svolte nell’area in esame e ne caratterizza l’economia, il paesaggio collinare, le tradizioni e le forme identitarie, specialmente nellla zona centro-orientale, ossia nei territori che gravitano sui centri urbani di Casteggio, Broni e Stradella. Il lavoro si propone di approfondire anzitutto la valorizzazione della tipicità e del locale, riassunti e rappresentati nel termine terroir, che indica l’insieme degli elementi geomorfologici, climatici, antropici e culturali che rendono unico un prodotto (in questo caso il vino), mettendo così il locale al centro di un’analisi che si può estendere poi a riflessioni di ordine generale. L’indagine geografica ha studiato gli aspetti ambientali e quelli antropici, nonché le loro relazioni. Si è fatto riferimento ai fattori geologici, pedologici e climatici, che altresì sono gli elementi imprescindibili degli studi di «zonazione» che si occupano proprio dell’interazione tra viticoltura e ambiente. L’indagine geostorica-territoriale si è rivolta soprattutto ai seguenti temi: il paesaggio vitivinicolo; i tipi di vitigni impiantati e i relativi sistemi di coltivazione; le produzioni e la commercializzazione del prodotto; la rappresentazione delle proprietà e del territorio attraverso i catasti. Inoltre si approfondiscono i temi geoeconomici sia a scala globale sia a scala locale, grazie alla rielaborazione delle informazioni relative al settore produttivo. Il contesto locale pertanto è confrontato con quello regionale, nazionale e globale, al fine di comprenderne i legami, soprattutto in relazione alle attuali sfide geoeconomiche. / In this thesis we analyse the evolution of grape growing and wine making as two of the elements which have contributed to the shaping of the landscape in the Oltrepò Pavese and represent two of the main economic activities of this geographic area, with is often identified with them – particularly in the mid-western part, i.e., the areas around the towns of Casteggio, Broni and Stradella. My main goal is to investigate the ways in which the values of locality and typicity – represented by the term terroir – are promoted. “Terroir” stands for, and comprises, a number of elements such as geo-morphological and climatic features, as well as human and cultural factors, all of which contribute to the uniqueness of a product like wine. My research thus starts from, and gives prominence to, the local level, in order to formulate a set of observations from which more general conclusions may then be drawn. The geographical investigation focusses on the environmental and human factors as well as their interrelationships. In its course, we refer to factors such as geology, pedology and climate, the crucial elements of all studies of «zoning», which describe precisely the complex interaction between grape growing and the environment. The geo-historical analysis concentrates especially on thematic areas such as the landscape; the varieties of grape that are planted and the respective growing techniques; the production and marketing of the produce; the ways in which property boundaries and the territory have been represented in land registries. The geo-economic factors, at both the local and global levels, are investigated through the analysis of the data from the production sector. The local context is thus compared to the regional, national and global ones in order to better understand the nature of their interactions and provide useful insights in relation to the challenges posed by the current geo-economic scenarios.