Tesis por compendio / [EN] Pepper is a vegetable of extraordinary economic and social importance in our country. Unfortunately, the persistent exploitation of the land, the monoculture and the intensification of production processes, lead to the development of soil diseases. This coupled with the abiotic stress, mainly the salinity of waters and soil, suboptimal temperatures and water stress, can induce the appearance of physiological disorders in peppers as the Blossom-end rot (BER) and cracking or cracked, induce plant senescence and decrease not only production, but also the quality of the product. Salinity and water shortages are two among the biggest environmental problems that crops have to face in the Mediterranean area. A way to overcome the stresses under the prism of an ecological or integrated crop management, is the use of grafted plants as adaptation strategy. Although there has been remarkable progress in this technique (mainly in tomato, melon, watermelon), in the cultivation of pepper use remains rare. In this Doctoral thesis several pepper genotypes have been selected through different physiological parameters which indicate tolerance to salt and water stress. Commercial cultivars were grafted onto the selected genotypes and were grown under water stress, salinity and control conditions studying several physiological, agronomic responses and the interaction rootstock/scion. The results obtained concluded that genotypes selected and used as rootstocks improved commercial varieties to salt and water stress tolerance, both in terms of performance (commercial production) compared to other commercial characters and variety without grafting. Different physiological mechanisms explain the tolerance to stress, such as the ability to maintain the water potential through an osmotic adjustment, stimulation of the antioxidant system, exclusion or retention of toxic ions (Na+ and Cl-) in saline in the roots and the maintenance of photosynthesis which allows to maintain the metabolic functions of grafted plants and production. / [ES] El pimiento es una hortaliza de extraordinaria importancia económica y social en nuestro país. Lamentablemente, la persistente explotación del suelo, el monocultivo y la intensificación de los procesos de producción, conducen al desarrollo de enfermedades del suelo. Esto unido a los estreses abióticos, principalmente la salinidad de las aguas y del suelo, temperaturas subóptimas y estrés hídrico, puede inducir la aparición de fisiopatias en el pimiento como el Blossom-end rot (BER) y cracking o rajado, inducir senescencia vegetal y disminuir no solo la producción, sino también la calidad del producto. La salinidad y la escasez de agua son unos los mayores problemas medio ambientales a los que tienen que hacer frente los cultivos en el área Mediterránea. Un modo de sortear los estreses bajo el prisma de un manejo integrado o ecológico del cultivo, es la utilización de plantas injertadas como estrategia de adaptación. Aunque se ha producido un notable avance en esta técnica (principalmente en tomate, melón, sandía), en el cultivo del pimiento su utilización es poco frecuente aun. En esta Tesis Doctoral se han seleccionado mediante parámetros fisiológicos diferentes genotipos de pimiento tolerantes al estrés salino e hídrico. Los genotipos seleccionados fueron validados como patrones tolerantes a condiciones de estrés hídrico y salino injertados sobre una variedad comercial mediante el estudio de las respuestas fisiológicas, agronómicas y de la interacción patrón/variedad en ambas condiciones de estrés. De los resultados obtenidos se concluye que los genotipos seleccionados y utilizados como patrones mejoraron la tolerancia de las variedades comerciales a la salinidad, en términos de rendimiento (producción comercial) de frutos comparando con otros patrones comerciales y la variedad sin injertar. Diferentes mecanismos fisiológicos explican la tolerancia al estrés, como la capacidad de mantener el potencial hídrico mediante un ajuste osmótico, estimulación del sistema antioxidante, exclusión o retención de los iones tóxicos salinos (Na+ y Cl-) en las raíces y el mantenimiento de la fotosíntesis que permite mantener las funciones metabólicas de las plantas injertadas y la producción. / [CA] El pimentó és una hortalissa d'extraordinària importància econòmica i social al nostre país. Lamentablement, la persistent explotació del sòl, el monocultiu i la intensificació dels processos de producció, conduïxen al desenrotllament de malalties del sòl. Açò unit als estressos abiòtics, principalment la salinitat de les aigües i del sòl, temperatures subòptimes i estrés hídric, pot induir l'aparició de fisiopaties en el pimentó com el Blossom-end rot (BER) i cracking, induir senescència vegetal i disminuir no sols la producció, sinó també la qualitat del producte. La salinitat i l'escassetat d'aigua són uns els majors problemes mitjà ambientals als que han de fer front els cultius en l'àrea Mediterrània. Una manera de sortejar els estressos davall el prisma d'un maneig integrat o ecològic del cultiu, és la utilització de plantes empeltades com a estratègia d'adaptació. Encara que s'ha produït un notable avanç en esta técnica (principalment en tomaca, meló, meló d'alger), en el cultiu del pimentó la seua utilització és poc freqüent. En esta Tesi Doctoral s'han seleccionat per mitjà de paràmetres fisiològics diferents genotips de pimentó tolerants a l'estrés salí i hídric. Els genotips seleccionats van ser validats com a patrons tolerants a condicions d'estrés hídric i salí empeltats sobre una varietat comercial per mitjà de l'estudi de les respostes fisiològiques, agronòmiques i de la interacció patrón/variedad en ambdós condicions d'estrés. Dels resultats obtinguts es conclou que els genotips seleccionats i utilitzats com a patrons van millorar la tolerància de les varietats comercials a la salinitat, tant en termes de rendiment (producció comercial) de fruits comparant amb altres patrons comercials i la varietat sense empeltar. Diferents mecanismes fisiològics expliquen la tolerància a l'estrés, com la capacitat de mantindre el potencial hídric per mitjà d'un ajust osmòtic, estimulació del sistema antioxidant, exclusió o retenció dels ions tòxics salins (Na+ i Cl-) en les arrels i el manteniment de la fotosíntesi que permet mantindre les funcions metabòliques de les plantes empeltades i la producció. / Penella Casañ, C. (2015). SCREENING PEPPER GENOTYPES TO OBTAIN TOLERANT ROOTSTOCKS TO SALT AND WATER STRESS: PHYSIOLOGICAL AND AGRONOMICAL RESPONSES OF THE GRAFTED PLANTS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58767 / Premios Extraordinarios de tesis doctorales / Compendio

Tesis por compendio / [ES] El pimiento es un cultivo muy importante a nivel mundial, pero es sensible a la falta de agua y a la salinidad. No obstante, se puede mejorar la tolerancia mediante la técnica del injerto. El Instituto Valenciano de Investigaciones Agrarias y la Universidad Politécnica de Valencia han realizado estudios previos para seleccionar accesiones de pimiento tolerantes a ambos estreses, utilizando después una selección de ellos como portainjertos para estudiar los mecanismos fisiológicos de tolerancia y aumentar la rentabilidad de su producción. Sin embargo, después de todos estos estudios, la información disponible es limitada. En este sentido, los objetivos que se han planteado en esta tesis doctoral fueron: i) seleccionar nuevas accesiones tolerantes de pimiento a la salinidad y escasez de agua, para aumentar la disponibilidad de genotipos tolerantes y usarlos en futuros programas de mejora, con el objetivo final de obtener nuevos portainjertos con una tolerancia mejorada; ii) identificar a corto plazo los mecanismos fisiológicos de tolerancia al estrés hídrico de una accesión tolerante (A25) usada como portainjerto; iii) identificar a corto plazo los mecanismos fisiológicos de tolerancia a la salinidad de un nuevo portainjerto híbrido tolerante (NIBER®); iv) encontrar los principales mecanismos moleculares de tolerancia a la salinidad de una accesión tolerante (A25) respecto a una sensible (A6) desde el punto de vista transcriptómico. Una vez realizados estos ensayos, en primer lugar, pudimos relacionar positivamente la capacidad fotosintética y el mantenimiento del crecimiento en plantas tolerantes a estrés hídrico y salino, tanto sin injertar como injertadas; de hecho, basándonos principalmente en esta relación, seleccionamos las accesiones A34 y A31 como tolerantes a estrés salino e hídrico, respectivamente. Además, demostramos que el papel principal de la prolina en los estreses estudiados no está ligado a la bajada de potencial osmótico; sin embargo, se identificaron funciones protectoras de este aminoácido que, junto a otras moléculas antioxidantes como los fenoles, contribuyen en el pimiento a aumentar la tolerancia. Igualmente importante es el peróxido de hidrógeno, que se relacionó con la capacidad antioxidante en pimiento, funcionando como molécula señalizadora en estrés salino. Asimismo, la bajada de ácido abscísico y la modificación de la expresión de genes relacionados han sido también relevantes en condiciones de estrés salino para mantener la apertura estomática y, por consiguiente, el crecimiento en plantas sin injertar e injertadas sobre portainjertos tolerantes. Se demostró también que la limitación del transporte de Na+ a hojas, así como el transporte y acumulación eficiente de K+ en raíces y hojas, son esenciales para alcanzar la homeostasis iónica y por tanto la tolerancia en pimientos injertados sobre portainjertos tolerantes. Para finalizar, el estudio de las rutas moleculares fue una herramienta útil para confirmar el comportamiento fisiológico y agronómico de una accesión de pimiento previamente clasificada como tolerante a la salinidad, descubriendo además nuevos mecanismos no referenciados hasta el momento. Los genes diferencialmente expresados encontrados estaban relacionados con la señalización hormonal, el crecimiento y desarrollo de las plantas, la fotoprotección, la regulación de los transportadores de iones y la detoxificación de ROS. / [CA] El pimentó és un cultiu molt important mundialment, però és sensible a la falta d'aigua i la salinitat. No obstant això, es pot millorar la tolerància mitjançant la tècnica de l'empelt. L'Institut Valencià d'Investigacions Agràries i la Universitat Politècnica de València han fet estudis previs per a seleccionar accessions de pimentó tolerants a tots dos estressos i a continuació, una selecció d'entre elles es va utilitzar per a estudiar els mecanismes fisiològics de tolerància i augmentar la rendibilitat de la seua producció. No obstant això, després de tots aquests experiments, la informació encara és limitada. En aquest sentit, els objectius que s'han plantejat en aquesta tesi doctoral van ser: i) seleccionar noves accessions tolerants de pimentó a la salinitat i la falta d'aigua, per a augmentar la disponibilitat de genotips tolerants i usar-los en futurs programes de millora, amb l'objectiu final d'obtindre nous portaempelts amb una tolerància millorada; ii) identificar a curt termini els mecanismes fisiològics de tolerància a l'estrès hídric d'una accessió tolerant (A25) usada com portaempelt; iii) identificar a curt termini els mecanismes fisiològics de tolerància a la salinitat d'un nou portaempelt híbrid tolerant (NIBER®); iv) trobar els principals mecanismes moleculars de tolerància a la salinitat d'una accessió tolerant (A25) respecte a una sensible (A6) des d'un punt de vista de la transcriptòmica. Després de realitzar aquests assajos, en primer lloc, vam poder relacionar positivament la capacitat fotosintètica i el manteniment del creixement en plantes tolerants a l'estrès hídric i salí, tant sense empeltar com empeltades; de fet, basant-nos principalment en aquesta relació, vam seleccionar les accessions A34 i A31 com tolerants a l'estrès salí i hídric, respectivament. A més a més, vam demostrar que el paper principal de la prolina en els estressos estudiats no està lligat a la baixada de potencial osmòtic; en canvi, es van identificar diferents funcions protectores d'aquest aminoàcid, que, junt a altres molècules antioxidants com els fenols, contribueixen en el pimentó a combatre'ls. Igualment important és el peròxid d'hidrogen, que es va relacionar amb la capacitat antioxidant del pimentó, funcionant com a molècula senyalitzadora a l'estrès salí. Així mateix, la baixada d'àcid abscísic i la modificació de l'expressió de gens relacionats de la seua senyalització han sigut també rellevants en condicions d'estrès salí per a mantindre l'obertura estomàtica i per tant el creixement en plantes sense empeltar i empeltades amb portaempelts tolerants. Es va demostrar també que la limitació del transport de Na+ a les fulles, així com el transport i l'acumulació eficient de K+ a les arrels i les fulles, són essencials per a aconseguir l'homeòstasi iònica i per tant la tolerància en pimentons empeltats damunt portaempelts tolerants. Per concloure, l'estudi de les rutes moleculars va ser un instrument útil per a confirmar el comportament fisiològic i agronòmic d'una accessió de pimentó prèviament classificada com a tolerant, descobrint a més nous mecanismes no trobats fins ara. Els gens diferencialment expressats trobats estaven relacionats amb la senyalització hormonal, el creixement i el desenvolupament de les plantes, la fotoprotecció, la regulació dels transportadors de ions i la detoxificació de ROS. / [EN] Pepper culture is economically very important worldwide, although it is very sensitive to suboptimal conditions of water and high salinity. However, the tolerance to these stresses can be improved by the grafting technique. Previous studies of the Valencian Institute for Agricultural Research and the Polytechnic University of Valencia have been conducted to select pepper accessions that showed tolerance to both stresses, after which a further selection of them was used as rootstocks to find physiological mechanisms of tolerance and to increase its agronomic profit. However, after all these studies, the available information in this regard is still scarce. Therefore, the objectives of this thesis were to: i) screen new tolerant pepper accessions under high salt concentrations and suboptimal water conditions, to increase the availability of tolerant genotypes to be used in future breeding programmes, with the final aim of obtaining new and improved tolerant rootstocks; ii) identify the short-term physiological mechanisms of water stress tolerance of a tolerant accession (A25) used as a rootstock; iii) identify the physiological mechanisms of short-term tolerance to salinity of a new tolerant hybrid rootstock (NIBER®); and iv) find the main molecular pathways of salinity tolerance of a tolerant accession (A25) compared to a sensitive one (A6) by a transcriptomic approach. After conducting these studies, we firstly found a positive relationship between photosynthetic capacity and growth maintenance in plants that were tolerant to water or salt stress, both grafted or ungrafted; indeed, based mainly on this relationship, we selected accessions A34 and A31 as tolerant to salt and water stress, respectively. In addition, we were able to demonstrate that the main role of proline under salinity and water scarcity is not linked herein to the drop in osmotic potential; on the contrary, we identified different protective roles that, together with other antioxidant protective molecules such as phenols, contribute to the tolerance of pepper plants to these environmental stresses. Moreover, hydrogen peroxide, a reactive oxygen species, was found to play important roles in the antioxidant capacity of pepper, working as a signalling molecule under salinity stress. Furthermore, the drop in abscisic acid concentration and its signalling deregulation were also shown to maintain stomatal aperture and thus the growth of the scion when grafted onto tolerant rootstocks and ungrafted accessions under high salt concentration conditions. It was also demonstrated that a limitation of Na+ transport to leaves, as well as a more efficient transport and accumulation of K+ in roots and leaves, are essential to reach ion homeostasis and, thus, tolerance in pepper plants grafted onto tolerant rootstocks. Finally, the study of the molecular pathways of tolerance was a useful tool to confirm the physiological and agronomical behaviour of a pepper accession previously classified as tolerant, although new mechanisms were also found. The differentially expressed genes found were linked to hormonal signalling, plant growth and development, photoprotection, regulation of ion transporters and ROS detoxification. / Quiero agradecer al Instituto Valenciano de Investigaciones Agrarias (IVIA), al Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) y al Ministerio de Ciencia, Innovación y Universidades por darme la oportunidad de disfrutar de la beca predoctoral FPI-INIA (proyectos RTA2013-00022-C02-1 y RTA2017-00030-C02-00) con la que he realizado esta tesis doctoral y he podido aprender tanto todos estos años, asistir a los congresos y realizar las estancias de investigación en el extranjero. / López Serrano, L. (2021). Unravelling the Physiological and Genetic Adaptation of Grafted Pepper under Saline and Hydric Stresses [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/162875 / Compendio

Abiotic stress is a major constraint for crop productivity worldwide. To better understand the common biological mechanisms of abiotic stress responses in plants, we performed meta-analysis of 652 samples of RNA sequencing (RNA-Seq) data from 43 published abiotic stress experiments in Arabidopsis thaliana. These samples were categorized into eight different abiotic stresses including drought, heat, cold, salt, light and wounding. We developed a multi-step computational pipeline, which performs data downloading, preprocessing, read mapping, read counting and differential expression analyses for RNA-Seq data. We found that 5729 and 5062 genes are induced or repressed by only one type of abiotic stresses. There are only 18 and 12 genes that are induced or repressed by all stresses. The commonly induced genes are related to gene expression regulation by stress hormone abscisic acid. The commonly repressed genes are related to reduced growth and chloroplast activities. We compared stress responsive genes between any two types of stresses and found that heat and cold regulate similar set of genes. We also found that high light affects different set of genes than blue light and red light. Interestingly, ABA regulated genes are different from those regulated by other stresses. Finally, we found that membrane related genes are repressed by ABA, heat, cold and wounding but are up regulated by blue light and red light. The results from this work will be used to further characterize the gene regulatory networks underlying stress responsive genes in plants. / Master of Science / Abiotic stress is a major constraint for crop productivity worldwide. To better understand the common biological mechanisms of abiotic stress responses in plants, we performed analysis of 652 samples of RNA sequencing data from 43 published abiotic stress experiments in Arabidopsis thaliana. These samples were collected from eight different abiotic stresses including drought, heat, cold, salt, light and wounding. We identified genes that were induced or repressed by each of these stresses. We found that 5729 and 5062 genes are induced or repressed by only one type of abiotic stresses. There are only 18 and 12 genes that are induced or repressed by all stresses. The commonly induced genes are related to gene expression regulation by stress hormone. The commonly repressed genes are related to reduced growth. We compared stress responsive genes between any two types of stresses and found that heat and cold regulate similar set of genes. We also found that high light affects different set of genes than blue light and red light. Finally, we found that membrane related genes are repressed by stress hormone, heat, cold and wounding but are up regulated by blue light and red light. The results from this work will be used to further characterize the gene regulations underlying stress responsive genes in plants.

[ES] A escala mundial, la Citricultura es uno de los sectores dentro de la Fruticultura con mayor producción, superando los 158 millones de toneladas en el año, pero es sensible de un gran número de estreses abióticos al ser un cultivo subtropical. La baja temperatura es uno de los estreses abióticos que más afecta a los cítricos produciendo grandes pérdidas anuales. El cambio climático está muy presente dando lugar cambios en los patrones de El tiempo originando un gran número de olas de frío y calor. Pero gracias a la técnica del injerto y al uso de patrones de cítricos los problemas causados por los estreses abióticos pueden mejorarse. El IVIA cuenta con un programa de mejora de patrones cuyo objetivo es la búsqueda de nuevo material vegetal con el fin de satisfacer los problemas de la citricultura. Tradicionalmente, el patrón más tolerante a la baja temperatura es Poncirus trifoliata, el cual se han realizado la mayoría de los trabajos en la bibliografía. Como patrón sensible, se empleó Citrus macrophylla ya que se trata de un patrón del tipo limonero que se sabe popularmente de su sensibilidad al frío. También se empleó el patrón citrange Carrizo, el cual se trata de patrón comercial más cultivado en España en la actualidad y la variedad Taroco Rosso, que se sabe de su pigmentación a causa de la baja temperatura. Así pues, los capítulos planteados en la presente tesis fueron: 1. Estrés a baja temperatura a corto plazo, 2. Estrés a baja temperatura a largo plazo y 3. El efecto del patrón en la variedad Tarocco Rosso. / [CAT] A escala mundial, la Citricultura és un dels sectors dins de la Fruticultura amb més producció, superant els 158 milions de tones a l'any, però és sensible d'un gran nombre d'estressos abiòtics per ser un cultiu subtropical. La baixa temperatura és un dels estressos abiòtics que més afecta els cítrics produint grans pèrdues anuals. El canvi climàtic està molt present donant lloc a canvis en els patrons de El temps originant un gran nombre d'onades de fred i calor. Però gràcies a la tècnica de l'empelt i a l'ús de patrons de cítrics, els problemes causats pels estressos abiòtics es poden millorar. L'IVIA compta amb un programa de millora de patrons que te com a objectiu la recerca de nou material vegetal per tal de satisfer els problemes de la citricultura. Tradicionalment, el patró més tolerant a la baixa temperatura és Poncirus trifoliata, el qual s'han realitzat la majoria dels treballs a la bibliografia. Com a patró sensible, es va fer servir Citrus macrophylla ja que es tracta d'un patró del tipus llimoner que se sap popularment de la seva sensibilitat al fred. També es va emprar el patró citrange Carrizo, el qual es tracta del patró comercial més cultivat a Espanya actualment i la varietat Taroco Rosso, que se sap de la seva pigmentació a causa de la baixa temperatura. Així doncs, els capítols plantejats en aquesta tesi van ser: 1. Estrès a baixa temperatura a curt termini, 2. Estrès a baixa temperatura a llarg termini i 3. L'efecte del patró en la varietat Tarocco Rosso. / [EN] On a global scale, Citriculture is one of the sectors within Fruit Growing with the highest production, exceeding 158 million tons per year, but it is sensitive to many abiotic stresses as it is a subtropical crop. Low temperature is one of the abiotic stresses that most affects citrus, producing large annual losses. Climate change is very present, giving rise to changes in weather patterns, causing many cold and heat waves. But thanks to the grafting technique and the use of citrus rootstocks, problems caused by abiotic stresses can be improved. IVIA institute has a rootstock improvement program whose objective is to search for new plant material to satisfy the problems of Citriculture. Traditionally, the most low-temperature tolerant rootstock is Poncirus trifoliata, on which most of the work in the literature has been done. As a sensitive rootstock, Citrus macrophylla was used since it is a lemon type rootstock that is popularly known for its sensitivity to cold. The citrange Carrizo rootstock was also used, which is currently the most cultivated commercial rootstock in Spain, and the Taroco Rosso variety, which is known for its pigmentation due to low temperature. Thus, the chapters proposed in this thesis were: 1. Short-term low-temperature stress, 2. Long-term low-temperature stress, and 3. The rootstock effect on the Tarocco Rosso variety. / Primo Capella, MA. (2023). Caracterización fisiológica y molecular de la respuesta de patrones de cítricos a estrés por baja temperatura [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/192892

Brassinosteroids (BRs) have been recognized to alleviate damages caused by drought stress and to enhance tolerance to water deficit. Soaking of maize kernels before the sowing in solution with different 24-epibrassinolide concentrations (especially the 10-8 M) had a positive effect on growth of plants before and after the stress period, although it did not affected relative water content and photosynthetic parameters. After the recovery under optimal conditions there were no differences among the treatments. When compared to spraying, soaking of maize kernels was not proved to have any advantages, though its positive effect on plants germination under water deficit conditions could be possible. Based on the results of the second season experiment it is not possible to deduce the role of exogenous BRs application (spraying with 24-epibrassinolide) or endogenous BRs biosynthesis (spraying with biosynthesis inhibitor - brassinazole) in maize plants subjected to water deficit. However, decrease in relative water content in contrast to chlorophylls content increase during the days following after drought stress onset in both cultivars (contrastive in drought sensitivity) challenges for further investigation of this problem. Understanding the role of BRs in plant drought tolerance and resistance is...

A cana-de-açúcar é uma das principais culturas agrícolas plantadas no Brasil e apresenta significativa importância sócio-econômica e agroindustrial ao país. O cenário mundial encontrase bastante favorável no que concerne à comercialização de seus dois principais produtos derivados, o açúcar e o álcool, impulsionando o desenvolvimento do setor sucroalcooleiro nacional. Neste sentido, o melhoramento genético da cana-de-açúcar aparece como base fundamental para o desenvolvimento de novas variedades para a manutenção e incremento dos agronegócios da agroindústria sucroalcooleira. Técnicas de engenharia genética, como a transformação genética nuclear, estão trazendo excelentes resultados no melhoramento genético da cultura, permitindo diminuir o custo e o tempo de obtenção de novas variedades. Baseando-se na importância em se obter variedades tolerantes a diferentes estresses bióticos e abióticos que induzem perturbações metabólicas e ativam o processo de morte celular programada, o presente trabalho teve por objetivo transformar geneticamente a variedade de cana-de-açúcar RB835089 com o cDNA do gene AtBI-1 isolado de Arabidopsis thaliana, visando suprimir a indução do mecanismo de morte celular sob condição de estresse. Para isto, calos embriogênicos foram utilizados como explante alvo, empregando-se dois métodos de transformação, a cotransformação por biolística, e o mediado por Agrobacterium tumefaciens no qual foram testadas duas técnicas: (a) inoculação direta dos calos em suspensão bacteriana; e (b) agrobiolística que é o bombardeamento dos calos com partículas de tungstênio seguido da inoculação em suspensão bacteriana. A proteína AtBI-1 (Bax inhibitor-1) apresenta homólogos em outros organismos e está localizada na membrana do retículo endoplasmático. Ela apresenta funções citoprotetoras modulando o mecanismo de morte celular programada induzida por estresses bióticos e abióticos. Como resultados deste trabalho, diferentes taxas de eficiência da transformação genética foram obtidas pelo método mediado por A. tumefaciens nas duas técnicas testadas, sendo que suas taxas foram superiores às alcançadas pelo método de co-transformação por biolística. A expressão heteróloga do cDNA do gene AtBI-1 em cana-de-açúcar atenuou a indução das vias de morte celular em presença do antibiótico tunicamicina, indutor do estresse no retículo endoplasmático, sendo comprovado pela maior tolerância ao estresse das plantas transgênicas quando comparadas com as plantas não transformadas que foram afetas no crescimento do sistema radicular, conteúdo de clorofila total, apresentando sintomas típicos de morte celular programada como clorose foliar e morfologia irregular das raízes, com consequente morte do sistema radicular. / Sugarcane is one of the main crops planted in Brazil and presents significant socioeconomic and agribusiness importance to the country. The world scene is quite favorable as regards the marketing of its two main products, sugar and alcohol, driving the development of the national sugar-alcohol sector. Therefore, the sugarcane genetic breeding appears as the fundamental base for developing new varieties for the maintenance and increase of agribusiness in the sugarcane agroindustry. Genetic engineering techniques, such as the nuclear genetic transformation, are providing excellent results in genetic breeding of this crop allowing reducing the cost and time to obtain new varieties. Based on the importance of obtaining varieties tolerant to different biotic and abiotic stresses that induce metabolic disturbances and activate the process of programmed cell death, this work aimed to transform sugarcane variety RB835089 with the cDNA of AtBI-1 gene, isolated from Arabidopsis thaliana, to suppress the induction of the cell death mechanism under stress condition. For this, embryogenic calli were used as target explant, by using two methods of transformation, the cotransformation by biolistic, and mediated by Agrobacterium tumefaciens in which two techniques were tested: (a) direct inoculation of calli in bacterial suspension; (b) agrobiolistic which is the bombardment of calli with tungstein particles followed by inoculation in bacterial suspension. The AtBI-1 protein (Bax inhibitor-1) presents homologs in other organisms and is located in the endoplasmic reticulum membranes. It has cytoprotective functions by modulating the mechanism of programmed cell death induced by biotic and abiotic stresses. As results of this work, different efficiency rates in genetic transformation were obtained in the method mediated by A. tumefaciens in the two techniques tested, and that their rates were higher than those achieved using the cotransformation by biolistic. The heterologous expression of cDNA of AtBI-1 gene in sugarcane attenuated the induction of cell death pathways in the presence of tunicamycin antibiotic, an inducer of stress in the endoplasmic reticulum, being proven by the increased stress tolerance of transgenic plants compared with sugarcane wild type that were affected in the root growth, total chlorophyll content, showing typical symptoms of programmed cell death such as leaf chlorosis and irregular morphology of the roots, with subsequent death of the root system.

<p>Stress responsive genes play a key role in shaping the manner in which plants process and respond to environmental stress. Their gene products are linked to DNA transcription and its consequent translation into a response product. However, whilst these genes play a significant role in manufacturing responses to stressful stimuli, transcription factors coordinate access to these genes, specifically by accessing a gene&rsquo / s promoter region which houses transcription factor binding sites. Here transcriptional elements play a key role in mediating responses to environmental stress where each transcription factor binding site may constitute a potential response to a stress signal. Arabidopsis thaliana, a model organism, can be used to identify the mechanism of how transcription factors shape a plant&rsquo / s survival in a stressful environment. Whilst there are numerous plant stress research groups, globally there is a shortage of publicly available stress responsive gene databases. In addition a number of previous databases such as the Generation Challenge Programme&rsquo / s comparative plant stressresponsive gene catalogue, Stresslink and DRASTIC have become defunct whilst others have stagnated. There is currently a single Arabidopsis thaliana stress response database called STIFDB which was launched in 2008 and only covers abiotic stresses as handled by major abiotic stress responsive transcription factor families. Its data was sourced from microarray expression databases, contains numerous omissions as well as numerous erroneous entries and has not been updated since its inception.The Dragon Arabidopsis Stress Transcription Factor database (DASTF) was developed in response to the current lack of stress response gene resources. A total of 2333 entries were downloaded from SWISSPROT, manually curated and imported into DASTF. The entries represent 424 transcription factor families. Each entry has a corresponding SWISSPROT, ENTREZ GENBANK and TAIR accession number. The 5&rsquo / untranslated regions (UTR) of 417 families were scanned against TRANSFAC&rsquo / s binding site catalogue to identify binding sites. The relational database consists of two tables, namely a transcription factor table and a transcription factor family table called DASTF_TF and TF_Family respectively. Using a two-tier client-server architecture, a webserver was built with PHP, APACHE and MYSQL and the data was loaded into these tables with a PYTHON script. The DASTF database contains 60 entries which correspond to biotic stress and 167 correspond to abiotic stress while 2106 respond to biotic and/or abiotic stress. Users can search the database using text, family, chromosome and stress type search options. Online tools have been integrated into the DASTF&nbsp / database, such as HMMER, CLUSTALW, BLAST and HYDROCALCULATOR. User&rsquo / s can upload sequences to identify which transcription factor family their sequences belong to by using HMMER. The website can be accessed at http://apps.sanbi.ac.za/dastf/ and two updates per year are envisaged.</p>

<p>Stress responsive genes play a key role in shaping the manner in which plants process and respond to environmental stress. Their gene products are linked to DNA transcription and its consequent translation into a response product. However, whilst these genes play a significant role in manufacturing responses to stressful stimuli, transcription factors coordinate access to these genes, specifically by accessing a gene&rsquo / s promoter region which houses transcription factor binding sites. Here transcriptional elements play a key role in mediating responses to environmental stress where each transcription factor binding site may constitute a potential response to a stress signal. Arabidopsis thaliana, a model organism, can be used to identify the mechanism of how transcription factors shape a plant&rsquo / s survival in a stressful environment. Whilst there are numerous plant stress research groups, globally there is a shortage of publicly available stress responsive gene databases. In addition a number of previous databases such as the Generation Challenge Programme&rsquo / s comparative plant stressresponsive gene catalogue, Stresslink and DRASTIC have become defunct whilst others have stagnated. There is currently a single Arabidopsis thaliana stress response database called STIFDB which was launched in 2008 and only covers abiotic stresses as handled by major abiotic stress responsive transcription factor families. Its data was sourced from microarray expression databases, contains numerous omissions as well as numerous erroneous entries and has not been updated since its inception.The Dragon Arabidopsis Stress Transcription Factor database (DASTF) was developed in response to the current lack of stress response gene resources. A total of 2333 entries were downloaded from SWISSPROT, manually curated and imported into DASTF. The entries represent 424 transcription factor families. Each entry has a corresponding SWISSPROT, ENTREZ GENBANK and TAIR accession number. The 5&rsquo / untranslated regions (UTR) of 417 families were scanned against TRANSFAC&rsquo / s binding site catalogue to identify binding sites. The relational database consists of two tables, namely a transcription factor table and a transcription factor family table called DASTF_TF and TF_Family respectively. Using a two-tier client-server architecture, a webserver was built with PHP, APACHE and MYSQL and the data was loaded into these tables with a PYTHON script. The DASTF database contains 60 entries which correspond to biotic stress and 167 correspond to abiotic stress while 2106 respond to biotic and/or abiotic stress. Users can search the database using text, family, chromosome and stress type search options. Online tools have been integrated into the DASTF&nbsp / database, such as HMMER, CLUSTALW, BLAST and HYDROCALCULATOR. User&rsquo / s can upload sequences to identify which transcription factor family their sequences belong to by using HMMER. The website can be accessed at http://apps.sanbi.ac.za/dastf/ and two updates per year are envisaged.</p>

A cana-de-açúcar é uma das principais culturas agrícolas plantadas no Brasil e apresenta significativa importância sócio-econômica e agroindustrial ao país. O cenário mundial encontrase bastante favorável no que concerne à comercialização de seus dois principais produtos derivados, o açúcar e o álcool, impulsionando o desenvolvimento do setor sucroalcooleiro nacional. Neste sentido, o melhoramento genético da cana-de-açúcar aparece como base fundamental para o desenvolvimento de novas variedades para a manutenção e incremento dos agronegócios da agroindústria sucroalcooleira. Técnicas de engenharia genética, como a transformação genética nuclear, estão trazendo excelentes resultados no melhoramento genético da cultura, permitindo diminuir o custo e o tempo de obtenção de novas variedades. Baseando-se na importância em se obter variedades tolerantes a diferentes estresses bióticos e abióticos que induzem perturbações metabólicas e ativam o processo de morte celular programada, o presente trabalho teve por objetivo transformar geneticamente a variedade de cana-de-açúcar RB835089 com o cDNA do gene AtBI-1 isolado de Arabidopsis thaliana, visando suprimir a indução do mecanismo de morte celular sob condição de estresse. Para isto, calos embriogênicos foram utilizados como explante alvo, empregando-se dois métodos de transformação, a cotransformação por biolística, e o mediado por Agrobacterium tumefaciens no qual foram testadas duas técnicas: (a) inoculação direta dos calos em suspensão bacteriana; e (b) agrobiolística que é o bombardeamento dos calos com partículas de tungstênio seguido da inoculação em suspensão bacteriana. A proteína AtBI-1 (Bax inhibitor-1) apresenta homólogos em outros organismos e está localizada na membrana do retículo endoplasmático. Ela apresenta funções citoprotetoras modulando o mecanismo de morte celular programada induzida por estresses bióticos e abióticos. Como resultados deste trabalho, diferentes taxas de eficiência da transformação genética foram obtidas pelo método mediado por A. tumefaciens nas duas técnicas testadas, sendo que suas taxas foram superiores às alcançadas pelo método de co-transformação por biolística. A expressão heteróloga do cDNA do gene AtBI-1 em cana-de-açúcar atenuou a indução das vias de morte celular em presença do antibiótico tunicamicina, indutor do estresse no retículo endoplasmático, sendo comprovado pela maior tolerância ao estresse das plantas transgênicas quando comparadas com as plantas não transformadas que foram afetas no crescimento do sistema radicular, conteúdo de clorofila total, apresentando sintomas típicos de morte celular programada como clorose foliar e morfologia irregular das raízes, com consequente morte do sistema radicular. / Sugarcane is one of the main crops planted in Brazil and presents significant socioeconomic and agribusiness importance to the country. The world scene is quite favorable as regards the marketing of its two main products, sugar and alcohol, driving the development of the national sugar-alcohol sector. Therefore, the sugarcane genetic breeding appears as the fundamental base for developing new varieties for the maintenance and increase of agribusiness in the sugarcane agroindustry. Genetic engineering techniques, such as the nuclear genetic transformation, are providing excellent results in genetic breeding of this crop allowing reducing the cost and time to obtain new varieties. Based on the importance of obtaining varieties tolerant to different biotic and abiotic stresses that induce metabolic disturbances and activate the process of programmed cell death, this work aimed to transform sugarcane variety RB835089 with the cDNA of AtBI-1 gene, isolated from Arabidopsis thaliana, to suppress the induction of the cell death mechanism under stress condition. For this, embryogenic calli were used as target explant, by using two methods of transformation, the cotransformation by biolistic, and mediated by Agrobacterium tumefaciens in which two techniques were tested: (a) direct inoculation of calli in bacterial suspension; (b) agrobiolistic which is the bombardment of calli with tungstein particles followed by inoculation in bacterial suspension. The AtBI-1 protein (Bax inhibitor-1) presents homologs in other organisms and is located in the endoplasmic reticulum membranes. It has cytoprotective functions by modulating the mechanism of programmed cell death induced by biotic and abiotic stresses. As results of this work, different efficiency rates in genetic transformation were obtained in the method mediated by A. tumefaciens in the two techniques tested, and that their rates were higher than those achieved using the cotransformation by biolistic. The heterologous expression of cDNA of AtBI-1 gene in sugarcane attenuated the induction of cell death pathways in the presence of tunicamycin antibiotic, an inducer of stress in the endoplasmic reticulum, being proven by the increased stress tolerance of transgenic plants compared with sugarcane wild type that were affected in the root growth, total chlorophyll content, showing typical symptoms of programmed cell death such as leaf chlorosis and irregular morphology of the roots, with subsequent death of the root system.

Un des principaux enjeux de l’amélioration des plantes consiste aujourd’hui à faire face au changement climatique, en assurant un rendement élevé et plus stable dans des systèmes agricoles économes en intrants (eau, fertilisants) et respectueux de l’environnement. Les nouvelles variétés de blé devront non seulement être tolérantes aux stress hydriques et aux fortes températures, mais aussi continuer à être productives avec des apports limités en fertilisation, tout en maintenant une qualité du grain adaptés aux différents usages. De nouvelles méthodes de prédiction des réponses des blés à ces stress sont indispensables pour avancer dans cette direction. Dans ce travail, nous avons tout d’abord identifié les stress qui régissaient les interactions entre génotypes et les environnements (GxE) dans les essais considérés, puis développé un modèle génomique de l’adaptation à un stress environnemental (Factorial Regression genomic Best Linear Unbiased Prediction ou FR-gBLUP), en particulier pour le stress hydrique. En émettant l’hypothèse que plus des variétés de blés sont génétiquement proches, plus elles répondront de façon similaire à un stress environnemental donné, nous avons mesuré par validation croisée des gains de précision de prédiction par rapport à un modèle additif variant entre 3.5% et 15.4%. Des simulations complètent l’étude en démontrant que plus la part de variance expliquée par les réponses au stress considéré est importante, plus le modèle FR-gBLUP apporte un gain de précision. Pour prédire les réponses variétales à un stress particulier, les environnements doivent être finement caractérisés pour les stress limitant le développement des plantes. En nous intéressant plus particulièrement au stress azoté en France, nous avons établi des indicateurs de stress à partir d’un modèle de culture, et les avons comparés à des indicateurs classiques, tels que le type de conduite azotée ou l’azote disponible. Nous avons ainsi mis en évidence l’intérêt des modèles de culture pour caractériser les interactions GxE et pour prédire la réponse génomique au stress azoté, à condition que le signal d’interaction soit assez fort. Au-delà de l’application potentielle de ces méthodes pour la sélection ou la recommandation de variétés de blés plus adaptées ou plus résistantes au changement climatique, les résultats de ce travail démontrent aussi l’intérêt de la complémentarité des approches éco-physiologiques et génétiques. / In a climate change context, assuring high and stable yield in more sustainable agricultural systems is a major challenge for plant breeding. We are aiming for future wheat varieties which will be heat and drought tolerant, and also productive in limited fertilization input environments. New prediction methods of the response to these stresses are needed to move forward. In this study, we first identified stresses that generated interactions between genotypes and environments (GxE) in our experimental trials and then developed a genomic model for adaptation to a particular environmental stress (Factorial Regression genomic Best Linear Unbiased Prediction ou FR-gBLUP), in our case drought. This model hypothesizes that the more individuals are genetically close, the more their response to a stress will resemble. We used cross-validations to measure prediction accuracy gains compared to an additive model and observed gains between 3.5% and 15.4%. Besides, simulation studies showed that the more the variance explained by the responses to the stress is important, the more the FR-gBLUP model will improve the additive model. Furthermore, fine characterization of the stresses limiting the plants’ growth is required to predict varietal responses to a particular stress. We focused on the particular case of nitrogen stress in France. By establishing crop model based stress indicators and comparing them to classical indicators, such as the management system or the available nitrogen, we pointed out the interest of crop model to characterize GxE interactions and to predict the genomic response to nitrogen stress, as long as the GxE interaction signal is strong enough. Beyond the potential applications of these methods for breeding or recommendation for varieties more adapted or tolerant to environmental stresses, this study also raises the interest of coupling eco-physiological and genetics approaches.