No description available.

Considerable variation exists both within and between species in nuclear DNA content. Despite there being no obvious functional role for much of this DNA, many studies have reported phenotypic correlations with genome size at various taxonomic levels. This suggests that DNA plays a functional role beyond the traditionally understood mechanisms. One such example of a phenotypic correlation with DNA content is present in the genus Silene, where a negative correlation between DNA content and flower size exists within and between species. This relationship is consistent with the direction of sexual dimorphism in DNA content (caused by heteromorphic sex-chromosomes) and flower size in the most studied species in the genus: S. latifolia. This thesis takes a comparative approach between two closely related species in the genus (S. latifolia and S. marizii), which differ markedly in their nuclear DNA content, in order to investigate the nature and phenotypic impacts of variation in DNA content. A phenotypic survey from a number of S. marizii populations reveals that the pattern of DNA content variation in this species is very different to that in S. latifolia. In particular, phenotypic correlations with DNA content appear be much weaker, whilst sexual dimorphism in DNA content, when present, appears to occur in either direction. A survey of interspecific hybrids suggests that this may be due to an enlarged S. marizii X-chromosome and that DNA content in hybrids may be biased with regard to their parents. Repetitive elements may be significant constituents of plant genomes. A study of Ty1-copia class retrotransposons in the two species reveals that they are present as a large and highly heterogeneous population. Phylogenetic analysis of these elements suggests a substantial degree of genetic isolation between the two species. Finally, an assessment of the flow-cytometric method, used to estimate DNA content, reveals substantial error associated with the method, but only limited evidence for stoichiometric effects.

No description available.

Parasitoides criam condições favoráveis para seu desenvolvimento regulando processos fisiológicos do hospedeiro via a utilização de moléculas produzidas por tecidos maternos ou por tecidos derivados do parasitoide imaturo ou de simbiontes associados (vírus de poliDNA - PDV). Assim, essas moléculas se destacam como uma fonte preciosa para o desenvolvimento de métodos alternativos de controle de pragas. O objetivo desse trabalho foi o de explorar a interação hospedeiro-parasitoide, visando à identificação de moléculas que participem do processo de regulação hospedeira para o desenvolvimento de métodos alternativos de controle de pragas. A busca pela identificação dessas moléculas foi concentrada na interação Diatraea saccharalis (F.) (Lepidoptera: Crambidae) Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) pela avaliação i) do efeito do parasitismo na fisiologia digestiva do hospedeiro e ii) da contribuição da glândula de veneno e do ovário na produção de moléculas bioativas e iii) pela caracterização de transcritos produzidos por teratócitos desse parasitoide. O potencial de aplicação de moléculas derivadas da interação hospedeiro-parasitoide foi verificado pela caracterização da atividade de uma quitinase putativa isolada da associação Heliothis virescens (F.) (Lepidoptera: Noctuidae) Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae), via expressão heteróloga e transformação genética de plantas de fumo. Os resultados demonstraram que o parasitismo afeta a utilização do alimento por lagartas parasitadas, reduzindo as taxas de crescimento (RGR), consumo (RCR) e metabólica (RMR) relativas, enquanto aumenta a eficiência de conversão do digerido (ECD). O parasitismo por C. flavipes também aumentou a permanência do alimento no intestino do hospedeiro e a atividade de -amilase, sacarase e trealase em lagartas de D. saccharalis. Análises do transcriptoma da glândula de veneno e do ovário de C. flavipes indicaram a produção de muitas proteínas desconhecidas. Porém, foi possível identificar proteases, um inibidor de proteinase e uma proteína com ação antimicrobiana, produzidas pela glândula de veneno, e uma proteína de expressão precoce (ep1), como produto do ovário de C. flavipes. Dois transcritos isolados de teratócitos de C. flavipes foram putativamente identificados como serpina e fator de inibição da tradução (CfHTIF). Ambos os transcritos foram detectados em teratócitos após cinco dias do parasitismo, sendo que transcritos do CfHTIF também foram observados em hemócitos de hospedeiros parasitados. CfHTIF apresentou alta homologia a proteínas produzidas por PDVs associados a outras espécies de Cotesia, sugerindo a sua origem viral, sendo este o primeiro relato da utilização de teratócitos para a produção de proteínas virais voltadas à regulação hospedeira. A caracterização da atividade da quitinase de teratócitos de T. nigriceps e a avaliação do seu potencial biotecnológico via transgenia de plantas para o controle de lagartas de H. virescens indicou que, apesar dessa quitinase possuir capacidade de ligação à quitina coloidal e cristalina em ensaios in vitro, a mesma não demonstra qualquer atividade quitinolítica. Avaliações de plantas de fumo transformadas com o Tnchi não indicaram qualquer efeito deletério ao desenvolvimento de lagartas de H. virescens. Apesar da ausência de atividade quitinolítica, essa quitinase apresentou atividade antimicrobiana. A possibilidade de exploração dessa proteína na produção de plantas de interesse econômico é discutida. / Parasitoids regulate their hosts physiological processes in order to produce suitable conditions for their own development by employing molecules produced by maternal tissues, the immature parasitoid and derived tissues, and associated simbionts (polidnavirus PDV). These molecules represent, therefore, an untapped resource of new molecules for the development of alternative pest control methods. Our objective was to exploit the hostparasitoid interactions aiming at the identification of molecules involved in host regulation for their use in the development of alternative strategies for pest control. The search for new molecules was concentrated on the interaction Diatraea saccharalis (F.) (Lepidoptera: Crambidae) Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) by assessing i) the effects of parasitization on the host digestive physiology and ii) the contribution of the venom gland and ovary in producing regulatory molecules, and by iii) the characterization of cDNAs isolated from teratocytes of C. flavipes. The potential application of molecules from hostparasitoid associations was verified by characterizing the activity of a putative chitinase isolated from the interaction Heliothis virescens (F.) (Lepidoptera: Noctuidae) Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae) using recombinant proteins and geneticallymodified tobacco plants. Data obtained demonstrated parasitized larvae had reduced relative growth (RGR), consumption (RCR) and metabolic (RMR) rates, while an increased efficiency in the conversion of the digested food (ECD) was obtained as compared to unparasitized larvae. Larvae parasitized by C. flavipes retained the food in the gut for a longer period and had higher activities for -amylase, sacarase and trehalase if compared to control larvae. Analysis of the transcriptome of the venom gland and ovary of C. flavipes predicted a large number of unknown proteins. Nevertheless, several proteases, a protease inhibitor and an antimicrobial protein from the venom gland, and an early-expressed protein (ep1), with a putative role in the process of host regulation from the ovaries, were identified. Two cDNAs isolated from teratocytes of C. flavipes were putatively identified as a serpin and an eukaryote translation inhibitory factor (CfHTIF). Both were detected in teratocytes from day 5 of parasitism and onwards, with the CfHTIF being also detected in hemocytes of parasitized hosts. Comparative analysis of the CfHTIF indicated it is highly homologous to host translation inhibitory factors produced by PDVs associated with other species of Cotesia, indicating its possible viral origin and suggesting this to be the first record of teratocytes as a source of PDV-derived proteins for host regulation. The characterization of the activity from the chitinase isolated from teratocytes of T. nigreceps (Tnchi) and the evaluation of its biotechnological potential via plant transgenesis to control larvae of H. virescens indicated this chitinase can bind to colloidal and crystalline chitins in in vitro assays, but it does not display chitinolytic activity. Assays with transformed tobacco plants expressing Tnchi did not result in any effect to H. virescens larval development and survival. Although Tnchi did not have any chitinolytic activity, it did show to have an antimicrobial effect. The possible exploitation of this protein for production of economically-important plants is dicussed.

How are neuromodulatory networks organised to adapt sensory discrimination for different contexts? I hypothesised that neurons within a sensory circuit express different neuromodulatory receptors for differential modulation. Here I aimed to use the simple and genetically amenable Drosophila larval Mushroom Body (MB) calyx, a higher order processing area involved in learned odour discrimination, as a model to map octopamine (OA) neuromodulatory circuitry. I first identified olfactory projection neurons (PNs), a GABAergic feedback neuron and cholinergic extrinsic neurons as putative postsynaptic partners to OA neurons in the MB calyx using GFP reconstitution across synaptic partners. Next, I used novel EGFP-tagged OA receptors generated from recombination-mediated cassette exchange with MiMIC insertions in receptor genes to visualise endogenous expression patterns of OA receptors. Most notably, this is the first report of α2-adrenergic-like OA receptor localisation in any insect. For the first time, I showed that the α1-adrenergic-like OAMB localised to PN presynaptic terminals in the calyx; while Octβ1R localised diffusely in the calyx, resembling the innervation pattern of MB neuron dendrites. I detected EGFP-tagged Octα2R and Octβ2R in some PN cell bodies but not in neuron terminals - suggesting that Octα2R and Octβ2R may be expressed in some PNs, provided the misfolded fusion proteins are retained in the cell bodies of the neurons they are normally expressed in. Furthermore, I found that Octα2R and GABAAR fusion proteins localised to OA cell bodies but not to neuronal terminals, suggesting that OA neurons are subjected to inhibition, again given that these are not artefacts of the fusion proteins. To obtain tools to study OA modulation in the larval calyx, I then confirmed the expression patterns of driver lines that more specifically labelled calyx-innervating OA and extrinsic neurons, and tested the efficacy of three OAMB receptor knockdown lines. This initial attempt of mapping OA receptors, while subjected to further verification and development, is consistent with my hypothesis that a single neuromodulatory source can regulate multiple neuronal types in the same circuit through the distribution of different types of neuromodulatory receptors. This provides a new perspective in how the anatomical organisation of neuromodulation within a sensory network may translate to flexible outputs.

No description available.

Parasitoides criam condições favoráveis para seu desenvolvimento regulando processos fisiológicos do hospedeiro via a utilização de moléculas produzidas por tecidos maternos ou por tecidos derivados do parasitoide imaturo ou de simbiontes associados (vírus de poliDNA - PDV). Assim, essas moléculas se destacam como uma fonte preciosa para o desenvolvimento de métodos alternativos de controle de pragas. O objetivo desse trabalho foi o de explorar a interação hospedeiro-parasitoide, visando à identificação de moléculas que participem do processo de regulação hospedeira para o desenvolvimento de métodos alternativos de controle de pragas. A busca pela identificação dessas moléculas foi concentrada na interação Diatraea saccharalis (F.) (Lepidoptera: Crambidae) Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) pela avaliação i) do efeito do parasitismo na fisiologia digestiva do hospedeiro e ii) da contribuição da glândula de veneno e do ovário na produção de moléculas bioativas e iii) pela caracterização de transcritos produzidos por teratócitos desse parasitoide. O potencial de aplicação de moléculas derivadas da interação hospedeiro-parasitoide foi verificado pela caracterização da atividade de uma quitinase putativa isolada da associação Heliothis virescens (F.) (Lepidoptera: Noctuidae) Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae), via expressão heteróloga e transformação genética de plantas de fumo. Os resultados demonstraram que o parasitismo afeta a utilização do alimento por lagartas parasitadas, reduzindo as taxas de crescimento (RGR), consumo (RCR) e metabólica (RMR) relativas, enquanto aumenta a eficiência de conversão do digerido (ECD). O parasitismo por C. flavipes também aumentou a permanência do alimento no intestino do hospedeiro e a atividade de -amilase, sacarase e trealase em lagartas de D. saccharalis. Análises do transcriptoma da glândula de veneno e do ovário de C. flavipes indicaram a produção de muitas proteínas desconhecidas. Porém, foi possível identificar proteases, um inibidor de proteinase e uma proteína com ação antimicrobiana, produzidas pela glândula de veneno, e uma proteína de expressão precoce (ep1), como produto do ovário de C. flavipes. Dois transcritos isolados de teratócitos de C. flavipes foram putativamente identificados como serpina e fator de inibição da tradução (CfHTIF). Ambos os transcritos foram detectados em teratócitos após cinco dias do parasitismo, sendo que transcritos do CfHTIF também foram observados em hemócitos de hospedeiros parasitados. CfHTIF apresentou alta homologia a proteínas produzidas por PDVs associados a outras espécies de Cotesia, sugerindo a sua origem viral, sendo este o primeiro relato da utilização de teratócitos para a produção de proteínas virais voltadas à regulação hospedeira. A caracterização da atividade da quitinase de teratócitos de T. nigriceps e a avaliação do seu potencial biotecnológico via transgenia de plantas para o controle de lagartas de H. virescens indicou que, apesar dessa quitinase possuir capacidade de ligação à quitina coloidal e cristalina em ensaios in vitro, a mesma não demonstra qualquer atividade quitinolítica. Avaliações de plantas de fumo transformadas com o Tnchi não indicaram qualquer efeito deletério ao desenvolvimento de lagartas de H. virescens. Apesar da ausência de atividade quitinolítica, essa quitinase apresentou atividade antimicrobiana. A possibilidade de exploração dessa proteína na produção de plantas de interesse econômico é discutida. / Parasitoids regulate their hosts physiological processes in order to produce suitable conditions for their own development by employing molecules produced by maternal tissues, the immature parasitoid and derived tissues, and associated simbionts (polidnavirus PDV). These molecules represent, therefore, an untapped resource of new molecules for the development of alternative pest control methods. Our objective was to exploit the hostparasitoid interactions aiming at the identification of molecules involved in host regulation for their use in the development of alternative strategies for pest control. The search for new molecules was concentrated on the interaction Diatraea saccharalis (F.) (Lepidoptera: Crambidae) Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) by assessing i) the effects of parasitization on the host digestive physiology and ii) the contribution of the venom gland and ovary in producing regulatory molecules, and by iii) the characterization of cDNAs isolated from teratocytes of C. flavipes. The potential application of molecules from hostparasitoid associations was verified by characterizing the activity of a putative chitinase isolated from the interaction Heliothis virescens (F.) (Lepidoptera: Noctuidae) Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae) using recombinant proteins and geneticallymodified tobacco plants. Data obtained demonstrated parasitized larvae had reduced relative growth (RGR), consumption (RCR) and metabolic (RMR) rates, while an increased efficiency in the conversion of the digested food (ECD) was obtained as compared to unparasitized larvae. Larvae parasitized by C. flavipes retained the food in the gut for a longer period and had higher activities for -amylase, sacarase and trehalase if compared to control larvae. Analysis of the transcriptome of the venom gland and ovary of C. flavipes predicted a large number of unknown proteins. Nevertheless, several proteases, a protease inhibitor and an antimicrobial protein from the venom gland, and an early-expressed protein (ep1), with a putative role in the process of host regulation from the ovaries, were identified. Two cDNAs isolated from teratocytes of C. flavipes were putatively identified as a serpin and an eukaryote translation inhibitory factor (CfHTIF). Both were detected in teratocytes from day 5 of parasitism and onwards, with the CfHTIF being also detected in hemocytes of parasitized hosts. Comparative analysis of the CfHTIF indicated it is highly homologous to host translation inhibitory factors produced by PDVs associated with other species of Cotesia, indicating its possible viral origin and suggesting this to be the first record of teratocytes as a source of PDV-derived proteins for host regulation. The characterization of the activity from the chitinase isolated from teratocytes of T. nigreceps (Tnchi) and the evaluation of its biotechnological potential via plant transgenesis to control larvae of H. virescens indicated this chitinase can bind to colloidal and crystalline chitins in in vitro assays, but it does not display chitinolytic activity. Assays with transformed tobacco plants expressing Tnchi did not result in any effect to H. virescens larval development and survival. Although Tnchi did not have any chitinolytic activity, it did show to have an antimicrobial effect. The possible exploitation of this protein for production of economically-important plants is dicussed.

No description available.

No description available.

Tesis por compendio / [ES] En las últimas dos décadas, la producción de caqui en España ha aumentado exponencialmente y la superficie de cultivo se ha multiplicado casi por ocho. En la actualidad, la producción de caqui está centralizada en el cultivar 'Rojo Brillante', que es mundialmente apreciado. Sin embargo, esta centralización supone una importante limitación comercial. En la presente Tesis se abordan dos objetivos principales: 1) Optimización de la tecnología pre y postcosecha con el fin de garantizar la calidad del caqui 'Rojo Brillante' durante la frigoconservación y el transporte a mercados internacionales. 2) Evaluación del comportamiento bajo condiciones mediterráneas de variedades introducidas de otras regiones productoras con el fin de ampliar el rango varietal de caqui. El primer objetivo de esta Tesis se logró a través de los estudios presentados en los Capítulos I al V. El segundo objetivo se abordó en los Capítulos VI y VII. En el Capítulo I se esclarecieron las causas del pardeamiento interno del fruto en los envíos a los mercados internacionales. La temperatura a la que se expone la fruta inmediatamente tras la aplicación del tratamiento de desastringencia con altas concentraciones de CO2 se identificó como el principal factor implicado en esta alteración. Los resultados obtenidos mostraron que esta alteración se puede evitar mediante la implementación de un período de atemperado de 24 h después del tratamiento con CO2, antes de conservar las frutas a bajas temperaturas. En el Capítulo II se evaluó la eficacia de un tratamiento de desastringencia recientemente patentado basado en la aplicación de una nueva cera que contiene etanol en su formulación. Los resultados mostraron que esta cera podría ser una alternativa al tratamiento convencional de desastringencia con altas concentraciones de CO2 cuando la fruta se envía a mercados lejanos a bajas temperaturas. La aplicación de la nueva cera antes de conservación en frío provocó la pérdida de astringencia de la fruta tras 30 días a 0 °C, preservando la firmeza y la calidad interna. Los resultados del Capítulo III demostraron que la realización de dos aplicaciones de ácido giberélico (AG) en precosecha permite retrasar el proceso de maduración de la fruta en el árbol con respecto a una sola aplicación. La combinación de AG en precosecha y 1-metilciclopropeno (1-MCP) en postcosecha resultó en una mayor calidad del fruto durante la frigoconservación en comparación con la aplicación únicamente de 1-MCP. Además, la fruta tratada con múltiples aplicaciones de AG mostró una firmeza ligeramente mayor tras de conservación a baja temperatura. En el Capítulo IV se demostró que, paralelamente al retraso de la maduración, el tratamiento con AG también retrasa la senescencia del cáliz, incrementando la calidad externa del fruto. La senescencia del cáliz durante la maduración del fruto se relacionó con una disminución de los parámetros de fluorescencia de clorofila (Fo, Fm y Fv/Fm). En el Capítulo V se estudiaron las condiciones óptimas de almacenamiento del caqui producido bajo cultivo ecológico. Según los resultados, no se deben almacenar los frutos cosechados con firmeza inferior a 30 N. La calidad del fruto durante la conservación dependió de las condiciones de almacenamiento, momento de aplicación del tratamiento de deastringencia y estado de madurez inicial. Por último, en los Capítulos VI y VII se abordó la evaluación bajo condiciones mediterráneas de 14 variedades de caquis no-astringentes procedentes de otros países. Se identificaron las variedades tempranas y tardías que pueden ser potencialmente interesantes para ampliar el período de cosecha en nuestra región. Los estudios postcosecha mostraron que todas las variedades estudiadas presentan una buena aptitud para ser comercializadas en los mercados nacionales y europeos. Sin embargo, la sensibilidad a los daños por frío que presentaron algunas de las variedades estudiadas podría limitar su comercialización a países de ultramar. Además, se observó que la respuesta al tratamiento con 1-MCP, para el control de los daños por frío, dependió en gran medida de la variedad. / [CA] En les últimes dues dècades, la producció de caqui a Espanya ha augmentat exponencialment i la superfície de cultiu s'ha multiplicat quasi per huit vegades. En l'actualitat, la producció de caqui està centralitzada en el la cultivar 'Rojo Brillante', que és mundialment apreciat. Malgrat això, aquesta centralització suposa d'una banda una important limitació comercial, ja que la producció es concentra en un període de collita relativament curt i, d'altra banda implica un alt risc fitosanitari. En la present Tesi s'aborden dos objectius principals: 1) Optimització de la tecnologia pre i postcollita amb la finalitat de garantir la qualitat del caqui 'Rojo brillante' durant la frigoconservació i el transport a mercats internacionals. 2) Avaluació del comportament de varietats introduïdes d'altres regions productores sota condicions mediterrànies amb la finalitat d'ampliar el rang varietal de caqui. En el Capítol I es van esclarir les causes de l l'enfosquiment intern. La temperatura a la qual s'exposa la fruita immediatament després de l'aplicació del tractament de desastringència amb altes concentracions de CO¿ es va identificar com el principal factor implicat en aquesta alteració. Els resultats obtinguts van mostrar que aquesta alteració es pot evitar mitjançant la implementació d'un període de temperat de 24 h després del tractament amb CO¿, abans de transferir la fruita a baixes temperatures. En el Capítol II es va avaluar l'eficàcia d'un tractament de desastringència recentment patentat basat en l'aplicació d'una nova cera que conté etanol en la seua formulació en caquis 'Rojo Brillante' i 'Triumph'. Els resultats van mostrar que aquesta cera podria ser una alternativa al tractament convencional de desastringència amb altes concentracions de CO¿ quan la fruita s'envia a mercats llunyans a baixes temperatures. L'aplicació de la nova cera abans de conservació en fred va provocar la pèrdua d'astringència de la fruita després de 30 dies a 0 °C, preservant la fermesa i la qualitat interna. Els resultats del Capítol III van demostrar que l'aplicació de dos tractaments d'àcid giberèlic (AG) en precollita permet retardar el procés de maduració de la fruita en l'arbre respecte a una sola aplicació. La combinació de AG en precollita i 1-metilciclopropeno (1-MCP) en postcollita va incrementar la qualitat del fruit durant la frigoconservació en comparació amb l'aplicació únicament de 1-MCP. A més, la fruita tractada amb múltiples aplicacions de AG va mostrar una fermesa lleugerament major després de conservació a baixa temperatura; no obstant això, una sola aplicació de AG també va ser eficaç per a previndre la manifestació de danys per fred en la fruita. En el Capítol IV es va demostrar que, paral·lelament al retard de la maduració, el tractament amb AG també retarda la senescència del calze, incrementant la qualitat externa del fruit. La senescència del calze durant la maduració del fruit es va relacionar amb una disminució dels paràmetres de fluorescència de clorofil·la (Fo, Fm i Fv/Fm). En el Capítol V es van estudiar les condicions òptimes d'emmagatzematge del caqui produït baix cultiu ecològic. D'acord amb els resultats obtinguts, no s'han d'emmagatzemar els fruits collits amb fermesa inferior a 30 N. La conservació del fruit va dependre de les condicions d'emmagatzematge, moment d'aplicació del tractament de desastringència i estat de maduresa de la fruita. Finalment, en els Capítols VI i VII es va abordar l'avaluació de 14 varietats de caquis no-astringents. Es van identificar les varietats primerenques i tardanes que poden ser potencialment interessants per a ampliar el període de collita. D'altra banda, els estudis postcollita van mostrar que totes les varietats estudiades presenten una bona aptitud per a ser comercialitzades en els mercats nacionals i europeus. No obstant això, la sensibilitat als danys per fred que van presentar algunes de les varietats estudiades podria limitar la seua comercialització a països d'ultramar. A més, es va observar que la resposta al tractament amb 1-MCP, per al control dels danys per fred, va dependre en gran manera de la varietat. / [EN] In the last two decades, persimmon production in Spain has increased exponentially and the cultivation area has expanded almost eight-fold. The current production of persimmon is focused on the cultivar 'Rojo Brillante', which is appreciated worldwide due to the high quality of the fruit. Nevertheless, centralized production of this single cultivar implies a major commercial limitation as its high volume of production is concentrated in a relative short harvesting period. Furthermore, it also implies a high phytosanitary risk. In this context, this Thesis addresses two main objectives: 1) Optimization of pre- and postharvest technology in order to guarantee the quality of 'Rojo Brillante' persimmon after cold storage and transportation to overseas markets. 2) Evaluation of the behavior of foreign varieties of persimmon under Mediterranean conditions in order to extend the varietal range. The first objective of this Thesis was tackled through the studies presented in Chapters I to V. The second objective was covered in Chapters VI and VII. Chapter I dealt with the causes of internal browning disorder manifested after cold shipment of 'Rojo Brillante' persimmons to overseas markets. The temperature to which fruit is exposed immediately after CO2 deastringency treatment was identified as the main factor involved in this alteration. Our results showed that this disorder can be avoided by implementing an attemperation period of 24 h after the CO2 treatment, before transferring fruit to cold storage. In Chapter II, the effectiveness of a recently patented deastringency treatment based on applying a new wax containing ethanol was assayed in 'Rojo Brillante' and 'Triumph' persimmons. The use of this new ethanol-based wax could be a potential alternative to the conventional CO2 deastringency treatment when the fruit are sent to distant overseas markets at low temperatures. Application of the new wax before cold storage led to loss of fruit astringency after 30 days at 0 °C while preserving fruit firmness and internal quality. The results of Chapter III demonstrated that two applications of gibberellic acid (GA) made it possible to delay the fruit maturity process on the tree more than with just a single application. The combination of GA and 1-methylciclopropene (1-MCP) preserved the fruit quality better than with the application of 1-MCP alone during cold storage. Moreover, the fruit treated by multiple GA applications showed a slightly higher firmness after cold storage. However, a single GA application was also effective in preventing the manifestation of chilling injury (CI) in fruit. Chapter IV demonstrated that in parallel to delaying maturity, the GA treatment also delayed calyx senescence, which meant that the fruit preserved a good appearance. The calyx lobe senescence during fruit ripening was linked to a decrease in all Chlorophyll Fluorescence Imaging (CFI) parameters (Fo, Fm, and Fv/Fm). Chapter V addressed the optimization of storage conditions for organic persimmons. According to our results, fruit harvested with a firmness lower than 30 N must not be stored. Fruit harvested with a higher level of firmness could be stored for up to three weeks depending on the storage conditions, the moment of application of the CO2 deastringency treatment, and the stage of fruit maturity. The longest storage period (3 weeks) was achieved when fruit were harvested with a firmness of around 45 N, submitted to CO2 treatment and then stored at 15 °C. Finally, 14 foreign varieties grown under Mediterranean conditions were evaluated to identify early- and late-season varieties with potential to extend the harvesting period. This is presented in Chapters VI and VII. In general, all the evaluated varieties fulfilled the quality criteria to be commercialized in domestic and European markets. However, sensitivity to CI was variety dependent and response to 1-MCP treatment was also observed to depend on the variety. / This study has been supported by the Instituto Nacional de Tecnología Agraria y Alimentaria de España (INIA) and Fondo Europeo de Desarrollo Regional (FEDER) through the projects RTA 2013-00043-C02-01 and RTA2017-00045-C02-01. In addition, it has been supported by the Valencian Institute for Agricultural Research (Project N° 51910). This study has also been founded by the Consellería de Educación, Investigación, Cultura y Deporte de la Comunidad Valenciana (project GV/2016/183). Ayoub Fathi Najafabadi thanks the INIA for grant FPI-INIA #43 (CPD2015-0151). The authors thank Fomesa Fruitech S.L.U. and Natural Hand S. L. for their technical support, Cooperativa Agrícola Ntra Sra de Loreto for its technical support and for making the plots and fruit used in this study available and Plant Production Department (Instituto Valenciano de Investigaciones Agrarias) for providing the fruit weight data and the photographs of the different varieties. / Fathi Najafabadi, A. (2021). Optimization of postharvest Technology for "Rojo brillante" Persimmon and Introduction of New Varieties in the Mediterranean Area [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171252 / Compendio