A aplicação de ar quente em videiras foi primeiramente realizada na fazenda do Sr. Florenzo Lazo, localizada no Chile, onde havia a necessidade de combater os efeitos negativos das freqüentes geadas que resultava em severos danos à lavoura. Por este motivo o Sr. Florenzo inventou uma máquina que aplicava ar quente com baixa umidade e tinha por objetivo dispersar o ar frio proveniente das geadas. Após certo tempo, foi observado pelo produtor que no local onde a máquina havia operado com maior frequência as plantas apresentavam-se com uma coloração mais escura e com sinais de maior vitalidade. Seguindo estas observações, relacionamos estes efeitos a um possível aumento nos fito-hormônios relacionados ao estresse vegetal e à SAR (Systemic Resistence Adquired), como o ácido salicílico (AS), ácido jasmônico (AJ) e ácido abscísico (ABA), além de fazer uma correlação com alguns resultados de pós-colheita importantes para a comercialização, como: Sólidos solúveis, firmeza e coloração. Para isso foi montado um experimento que foi conduzido em duas parcelas, sendo uma com tratamento TPC e outra apenas com o tratamento convencional com distância padronizada em 3,2 metros entre linhas por 2,0 metros entre planta. As amostras eram coletadas diariamente e devidamente acondicionadas. Ao final da safra, as amostras foram transportadas para o laboratório de estresse e neurofisiologia da universidade de São Paulo (LEPSE), onde foram novamente armazenadas em um Ultra-freezer - 86ºC. As analises fisiológicas de pós-colheita foram realizadas no departamento de pós-colheita da universidade de São Paulo onde foram analisados os teores de sólidos solúveis, coloração e firmeza das bagas de uva. As amostras de folhas foram maceradas e uniformizadas no LEPSE e enviadas para o laboratório de ecotoxicologia do Centro de Energia Nuclear na Agricultura (CENA) onde foram mensurados os teores dos fito-hormônios pelo método de espectrometria de massa. Para ambas as analises foram feitos testes estatísticos utilizando o programa SAS®. Não houve alteração de SS e firmeza entre os dois tratamentos para as características fisiológicas de póscolheita. Entretanto foi notado uma redução na coloração avermelhada para os cachos tratados com TPC seguindo o sistema de colorimetria proposto pelo CIE. Não houve alterações significantes para as variáveis ABA, AJ e AS para o efeito tratamento e para a analise de correlação. Entretanto notou-se significância entre o efeito dias para as variáveis ABA e AJ. Não foi notada significância para o efeito dias para a variável AS. Por se tratar de um estresse rápido, a TPC parece não causar estresse imediato nas plantas, entretanto notou-se indução de estresse ao longo do tempo, possivelmente devido à resposta lenta de ABA que aparentemente está envolvida com RNA e à síntese de proteínas S e R- ABA que são igualmente efetivas. Já para o AJ sugere-se que houve a produção de H2O2 por derivados de oligogalacturonideos, liberados por ação da enzima poligalacturonase, e um segundo mensageiro que ativam genes defensivos (genes tardios). O aumento na biossíntese do ABA e do AJ parece ter suprimido genes envolvidos na biossíntese do AS. / The application of hot air in grapevines was first held on the farm of Mr. Florenzo Lazo, located in Chile, to combat the negative effects of frequent frosts that resulted in severe damage to the crop. For this reason Mr. Florenzo invented a machine that applied hot air with low humidity and aimed to disperse the cold air from the frost. After a while, it was observed by the producer that where the machine had operated more frequently plants showed up with a darker and more signs of vitality. Following these observations, these effects relate to a possible increase in phytohormones related to plant stress and SAR (Systemic Resistance Adquired), such as salicylic acid (AS), jasmonic acid (AJ) and abscisic acid (ABA), besides making a correlation with results of some important postharvest for marketing, such as soluble solids, firmness and color. For this experiment was created that was conducted in two installments, the first one was treated with TPC and second one was applied only conventional treatment with standardized distance of 3.2 meters between lines by 2.0 meters between plant . The samples were collected daily and properly packed. At the end of the season, samples were transported to the laboratory stress and neurophysiology from the University of São Paulo (LEPSE), where they were again stored in an Ultra-freezer - 86 degrees. The physiological analyses of post-harvest were performed at the Department of Postharvest in University of Sao Paulo where we analyzed the levels of soluble solids, firmness and color in grape berries. The leaf samples were uniform macerated at LEPSE and sent to the laboratory of ecotoxicology in the Center for Nuclear Energy in Agriculture (CENA) where we measured the levels of the phytohormones by the method of mass spectrometry. For both analyzes were performed statistical tests using SAS ® program. There wasn`t change between the two treatments on physiological post-harvest characteristics. There was no change of SS and firmly between the two treatments for the physiological of post-harvest characteristics. However it was noted a reduction in red color for bunches treated with TPC following the colorimetry system by CIE. There were no significant changes to the variables ABA, AJ and AS for the treatment effect and to analyze the correlation. However significance was noted between the effect variables ABA days and AJ. No significant effect was noted for days variable for AS. Since it is a stress fast TPC does not seem to cause immediate stress in plants but it was noticed induction of stress over time, possibly due to slow response to ABA which apparently is involved in the synthesis of RNA and proteins S and R-ABA that are equally effective. As for AJ suggests that there was the production of H2O2 by derivatives of oligogalacturonides, released by action of the enzyme polygalacturonase, and a second messenger that activates defensive genes (late genes). The increase in ABA biosynthesis and AJ appears to have deleted genes involved in the biosynthesis of AS.

No description available.

No description available.

A aplicação de ar quente em videiras foi primeiramente realizada na fazenda do Sr. Florenzo Lazo, localizada no Chile, onde havia a necessidade de combater os efeitos negativos das freqüentes geadas que resultava em severos danos à lavoura. Por este motivo o Sr. Florenzo inventou uma máquina que aplicava ar quente com baixa umidade e tinha por objetivo dispersar o ar frio proveniente das geadas. Após certo tempo, foi observado pelo produtor que no local onde a máquina havia operado com maior frequência as plantas apresentavam-se com uma coloração mais escura e com sinais de maior vitalidade. Seguindo estas observações, relacionamos estes efeitos a um possível aumento nos fito-hormônios relacionados ao estresse vegetal e à SAR (Systemic Resistence Adquired), como o ácido salicílico (AS), ácido jasmônico (AJ) e ácido abscísico (ABA), além de fazer uma correlação com alguns resultados de pós-colheita importantes para a comercialização, como: Sólidos solúveis, firmeza e coloração. Para isso foi montado um experimento que foi conduzido em duas parcelas, sendo uma com tratamento TPC e outra apenas com o tratamento convencional com distância padronizada em 3,2 metros entre linhas por 2,0 metros entre planta. As amostras eram coletadas diariamente e devidamente acondicionadas. Ao final da safra, as amostras foram transportadas para o laboratório de estresse e neurofisiologia da universidade de São Paulo (LEPSE), onde foram novamente armazenadas em um Ultra-freezer - 86ºC. As analises fisiológicas de pós-colheita foram realizadas no departamento de pós-colheita da universidade de São Paulo onde foram analisados os teores de sólidos solúveis, coloração e firmeza das bagas de uva. As amostras de folhas foram maceradas e uniformizadas no LEPSE e enviadas para o laboratório de ecotoxicologia do Centro de Energia Nuclear na Agricultura (CENA) onde foram mensurados os teores dos fito-hormônios pelo método de espectrometria de massa. Para ambas as analises foram feitos testes estatísticos utilizando o programa SAS®. Não houve alteração de SS e firmeza entre os dois tratamentos para as características fisiológicas de póscolheita. Entretanto foi notado uma redução na coloração avermelhada para os cachos tratados com TPC seguindo o sistema de colorimetria proposto pelo CIE. Não houve alterações significantes para as variáveis ABA, AJ e AS para o efeito tratamento e para a analise de correlação. Entretanto notou-se significância entre o efeito dias para as variáveis ABA e AJ. Não foi notada significância para o efeito dias para a variável AS. Por se tratar de um estresse rápido, a TPC parece não causar estresse imediato nas plantas, entretanto notou-se indução de estresse ao longo do tempo, possivelmente devido à resposta lenta de ABA que aparentemente está envolvida com RNA e à síntese de proteínas S e R- ABA que são igualmente efetivas. Já para o AJ sugere-se que houve a produção de H2O2 por derivados de oligogalacturonideos, liberados por ação da enzima poligalacturonase, e um segundo mensageiro que ativam genes defensivos (genes tardios). O aumento na biossíntese do ABA e do AJ parece ter suprimido genes envolvidos na biossíntese do AS. / The application of hot air in grapevines was first held on the farm of Mr. Florenzo Lazo, located in Chile, to combat the negative effects of frequent frosts that resulted in severe damage to the crop. For this reason Mr. Florenzo invented a machine that applied hot air with low humidity and aimed to disperse the cold air from the frost. After a while, it was observed by the producer that where the machine had operated more frequently plants showed up with a darker and more signs of vitality. Following these observations, these effects relate to a possible increase in phytohormones related to plant stress and SAR (Systemic Resistance Adquired), such as salicylic acid (AS), jasmonic acid (AJ) and abscisic acid (ABA), besides making a correlation with results of some important postharvest for marketing, such as soluble solids, firmness and color. For this experiment was created that was conducted in two installments, the first one was treated with TPC and second one was applied only conventional treatment with standardized distance of 3.2 meters between lines by 2.0 meters between plant . The samples were collected daily and properly packed. At the end of the season, samples were transported to the laboratory stress and neurophysiology from the University of São Paulo (LEPSE), where they were again stored in an Ultra-freezer - 86 degrees. The physiological analyses of post-harvest were performed at the Department of Postharvest in University of Sao Paulo where we analyzed the levels of soluble solids, firmness and color in grape berries. The leaf samples were uniform macerated at LEPSE and sent to the laboratory of ecotoxicology in the Center for Nuclear Energy in Agriculture (CENA) where we measured the levels of the phytohormones by the method of mass spectrometry. For both analyzes were performed statistical tests using SAS ® program. There wasn`t change between the two treatments on physiological post-harvest characteristics. There was no change of SS and firmly between the two treatments for the physiological of post-harvest characteristics. However it was noted a reduction in red color for bunches treated with TPC following the colorimetry system by CIE. There were no significant changes to the variables ABA, AJ and AS for the treatment effect and to analyze the correlation. However significance was noted between the effect variables ABA days and AJ. No significant effect was noted for days variable for AS. Since it is a stress fast TPC does not seem to cause immediate stress in plants but it was noticed induction of stress over time, possibly due to slow response to ABA which apparently is involved in the synthesis of RNA and proteins S and R-ABA that are equally effective. As for AJ suggests that there was the production of H2O2 by derivatives of oligogalacturonides, released by action of the enzyme polygalacturonase, and a second messenger that activates defensive genes (late genes). The increase in ABA biosynthesis and AJ appears to have deleted genes involved in the biosynthesis of AS.

Les bactéries rhizosphériques stimulatrices de croissance (PGPR) du genre Azospirillum sont utilisées commercialement pour leur capacité à stimuler la croissance et à augmenter le rendement des céréales via une relation associative complexe et peu comprise. L'objectif de cette étude a été d'utiliser les outils modernes de la métabolomique pour caractériser les mécanismes biochimiques activés par la souche A. lipoferum CRT1 chez son hôte, le maïs.L'analyse des contenus phytochimiques des racines, feuilles et sève ascendante a suggéré pour la première fois l'importance de la communication racine-feuille et des sucres simples dans l’augmentation de croissance et du potentiel de conversion photochimique de jeunes plantules par A. lipoferum CRT1. Une analyse transcriptomique a révélé un impact modéré au niveau des racines et des modifications de nombreux nœuds régulateurs des processus biologiques cellulaires des feuilles, dont ceux contrôlés par les auxines et l’acide abscissique. Des essais agronomiques conduits deux années consécutives sur quatre sites ont indiqué que l'augmentation de rendement par A. lipoferum CRT1 dérivait d’une sécurisation de la germination lors de stress environnementaux précoces et non de modifications des métabolomes (dont ceux liés à la nutrition azotée et phosphorée), de la croissance et du potentiel photosynthétique des plantules, des modifications qui étaient par contre liées aux contextes pédo-climatiques. La sécurisation de la germination était due à une accélération de la sortie de la radicule et de la consommation des sucres simples, et molécules apparentées, de la graine / Plant growth-promoting rhizobacteria (PGPR) of the genus Azospirillum are used commercially for their capacity to stimulate the growth and enhance the yield of cereal crops via an intricate, complex and poorly understood associative relationship. The aim of this study was to use modern metabolomics tools to decipher the biochemical mechanisms activated by A. lipoferum CRT1 in its maize host.The analysis of the phytochemical contents of roots, leaves and ascending sap revealed for the first time the importance of root-to-shoot communication and of simple sugars in the enhancement of growth and photochemical conversion potential of young plantlets by A. lipoferum CRT1. A transcriptomic analysis showed moderate impact on roots and a coordinate modulation of several regulatory nodes of cellular biological processes, including some mediated by auxins and abscissic acid. Agronomic field trials conducted two consecutive years in four sites correlated yield enhancement by A. lipoferum CRT1 to the securing of seed germination during environmental stresses. No correlation was found with modifications of plantlets metabolomes (including those linked to nitrogen and phosphorus nutrition), growth and photochemical conversion potential which were found to depend on additional soil and climate cues. Germination securing was due to a speeding of radicule emergence and of seed simple sugars consumption

Abiotic and biotic stresses lead to crop yield losses and ultimately negatively affect agriculture production. Elucidation of the mechanisms of plant stress responses and their regulation could help to understand plant defence and improve stress tolerance. Phytohormones stand behind both plant growth and developmental changes as well as stress signalling. This thesis summarises the results published in two articles focused on phytohormone dynamics in response to abiotic and biotic stresses, namely phosphate shortage and Plasmodiophora brassicae infection. A review article focuses in depth on strigolactones as master regulators of phosphate deficiency responses. The main emphasis is put on organ-specific reactions and exogenous phytohormone treatment with the potential to convey stress tolerance. In the case of phosphate shortage, the universal reaction in all organs was a decrease in active cytokinin trans-zeatin and gibberellin GA4 with a concurrent elevation of abscisic acid. Also, the high- affinity phosphate transporters (PHT1;4 and PHT1;7) exhibited increased gene expression within the whole plant. Shoot apical meristems showed numerous changes in gene expression and were the most affected organ during the lack of phosphate. Only in roots, we observed a substantial elevation of low active...

No description available.

The dioxygenase-cytochrome P450 fusion proteins (DOX-CYP) comprise a heme-containing enzyme family that shares structural and catalytic properties with mammalian prostaglandin H (PGH) synthases. 7,8-Linoleate diol synthase (7,8-LDS) of Gaeumannomyces graminis was first characterized, and DOX-CYP enzymes are of mechanistic and biological interest. The growing number of fungal genome sequences has revealed DOX-CYP homologues in medically and economically important species. The aim of this thesis was to identify novel members of the DOX-CYP fusion protein family. The devastating rice pathogen Magnaporthe oryzae contains two DOX-CYP genes. The fungus synthesizes 7S,8S-dihydroxyoctadecadienoic acid (7,8-DiHODE) by dioxygenation of linoleic acid to 8R-hydroperoxyoctadecadienoic acid (8R-HPODE), and subsequent isomerisation to the diol. 7,8-LDS of M. oryzae was identified by gene deletion, but the infection and reproduction processes of the Δ7,8-LDS strain were not altered. A mutant with constitutive protein kinase A activity profoundly changed the oxygenation profile, possibly due to post-translational modification. The human pathogens Aspergillus fumigatus and A. clavatus contain three DOX-CYP, designated psi producing oxygenase A (ppoA), ppoB, and ppoC, and form three oxylipins: 5S,8R-DiHODE, 8R,11S-DiHODE, and 10R-hydroxyoctadecadienoic acid.  PpoA was identified as 5,8-LDS, and ppoC as 10R-DOX. The 8,11-linoleate hydroperoxide isomerase activity was reduced by two imidazole-containing P450 inhibitors, miconazole and 1-benzylimidazole. PpoB could not be linked to the biosynthesis of 8,11-DiHODE for the following reasons: First, the 8,11-hydroperoxide isomerase activity was retained in A. fumigatus ΔppoB strains. Second, the P450 domain of the deduced ppoB of A. clavatus lacks a heme-thiolate cysteine ligand, presumably essential for hydroperoxide isomerase activity. Linoleate 9R-DOX activities of Aspergillus terreus and Lasiodiplodia theobromae were discovered. 9R-HPODE was further converted into unstable allene oxides, as judged by the accumulation of their hydrolysis products, α- and γ-ketols. These allene oxide synthase activities were specific for 9R-hydroperoxides. The 9R-DOX and AOS were found to have unique characteristics. In conclusion, novel DOX-CYP enzymes were identified in human and plant pathogenic fungi. These enzymes might be involved in biological processes, and show interesting catalytic similarities to human PGH synthase and thromboxane synthase (CYP5A).

No description available.

No description available.