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Submitted by Ana Costa (apcosta@porto.ucp.pt) on 2019-03-27T18:02:24Z No. of bitstreams: 1 TRue - Transition paths (ver o outro ficheiro para citação).pdf: 666586 bytes, checksum: 1a05acc1ccb9f8feffeafe1a5bdec67d (MD5) Approved for entry into archive by Maria João Pinto (mjpinto@porto.ucp.pt) on 2019-03-27T19:22:47Z (GMT) No. of bitstreams: 1 TRue - Transition paths (ver o outro ficheiro para citação).pdf: 666586 bytes, checksum: 1a05acc1ccb9f8feffeafe1a5bdec67d (MD5) Made available in DSpace on 2019-03-27T19:22:47Z (GMT). No. of bitstreams: 1 TRue - Transition paths (ver o outro ficheiro para citação).pdf: 666586 bytes, checksum: 1a05acc1ccb9f8feffeafe1a5bdec67d (MD5) Previous issue date: 2018 info:eu-repo/semantics/publishedVersion

BACKGROUND: The aim of this studywas to identify biochemical markers to predict internal browning disorders (IBD) in 'Rocha' pear. Fruits from five orchards were stored for 45 days under cold air followed by 100 days in browning-inducing controlled atmosphere (CA) conditions (1 kPaO(2) + 10 kPaCO(2)). RESULTS: Relationships between concentrations of ethanol (EtOH), acetaldehyde (AcDH) and ascorbic acid (AA), activities of peroxidase (POX) and polyphenoloxidase (PPO) and IBD incidence were established. The partial least square (PLS) model using the most promising markers, EtOH and AcDH, explained 89% of the variance in IBD incidence, whereas the univariate models based on the same markers explained between 89 and 94%. In contrast, the models based on AA levels and AA depletion rate only explained 57 and 82% of the variance in IBD incidence respectively. Model validation confirmed the robustness of EtOH for the prediction (R-2 = 0.91, RMSE= 11.1) and allowed proposing a threshold level of 30 mu L EtOH L-1 above which IBD may occur. Using this threshold value, the storage time limit associated with the occurrence of the first IBD symptoms was predicted with an acceptable RMSE of 9 days. CONCLUSION: Thiswork clearly identifies biochemical IBDmarkers for ` Rocha' pear and shows that dynamic changes in ethanol concentration during the beginning of storagemay be used to predict IBD development. Therefore the results presented herein represent a major step forward in the prediction of IBD in 'Rocha' pear.

1 página.- Resumen de la conferencia presentada en la Reunión celebrada en la ETSI Montes, Forestal y del Medio Natural de la Universidad Politécnica de Madrid, los días 7 y 8 de octubre de 2015., The pine wilt disease (PWD) is caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus, a microscopic worm that feeds off the host´s xylem cells and, under favourable edaphic-climatic conditions, is able to kill an adult tree in less than four months. It has become a devastating pest for pine forests leading to the yearly loss of thousands of pine trees worldwide, including P. pinaster plantations in Portugal. In the Iberian Peninsula it has, however, not yet significantly affected other Pinus species in the field, namely P. pinea, leading to the hypothesis that Pinus spp. have differential mechanisms that determine host susceptibility to the nematode. In the current presentation I will highlight some of the concerted Iberian efforts that have been undertaken at “Universidade Católica”, with collaboration with “Universidad de Extremadura” and “Misión Biológica de Galicia” (CSIC) in order to understand some of the anatomical, physiological, biochemical, and molecular aspects that underlie host susceptibility within different Pinus species. Controlled inoculations and an integrated analysis of several host traits allowed us to conclude that aspects related to disease resistance may be linked to stem anatomical traits, to the differential expression of specific genes, to the release of particular volatile organic compounds (VOCs), and to the constitutive and induced expression of defence molecules.

Chitosans and chitooligosaccharides (CHOS) are polysaccharides with a broad range of applications, including plant growth promoting activities. Both compounds have also been shown to have metal chelating properties. However, several factors, such as degree of polymerization, degree of deacetylation, pH, temperature, concentration, application method, viscosity and purity, can influence chitosan and CHOS mode of action. Most applications of chitosans and CHOS so far have been in the biomedical industry. But given that there is a great interested to find novel ways to enhance the plant's nutritional value (biofortification) or to modulate the capacity of plants to extract toxic metals from the soil (phytoremediation), a better understanding of chitosan and CHOS effects in plant systems is warranted. What are chitosans and CHOS? Before discussing the possible applications of these molecules, it is important to clarify what they are. Chitin, chitosans and CHOS are three inter-related compounds of polysaccharidic nature. Chitin was first isolated in 1811 (Domard and Domard, 2002), and it is the second most important biopolymer in the world after cellulose (Rinaudo, 2006). Even though its first isolation was in mushrooms, chitin has since been obtained from many other sources, including cell walls of several yeast and fungal strains and from the exoskeleton of crawfish, shrimp and crabs. It is composed of a long-chain homopolymer of N-acetyl-D-glucosamine (GlcNAc), (1–4)-linked 2-acetamido-2-deoxy-β-D-glucan (Park and Kim, 2010) and is insoluble in water, limiting its utilization in living systems (Park and Kim, 2010). It can, however be broken down into other molecules with higher solubility. Chitosan is one of such molecules. It is at least 50% deacetilated and it is aqueous in acidic media (Rinaudo, 2006; Aam et al., 2010). CHOS have a degree of polymerization higher than 20% and an average molecular weight less than 3900Da (Lodhi et al., 2014). Still, chitosans and CHOS can be very diverse in several features such as (i) sequence, (ii) degree and pattern of N-acetylation; (iii) fraction of N-acetylated residues; (iv) degree of polymerization; (v) molecular weight, and polydispersity. This vast degree of compositional variability is in fact one of the major obstacles in chitosan research. Comprehensive knowledge on their mode-of-action is still scarce, because most published studies are done with heterogeneous mixtures and because production of well-defined chitosans and CHOS is not easily done (Montilla et al., 2013). Further, chitosan is easily degraded into CHOS by naturally occurring hydrolytic enzymes in most living systems, including plants. Thus, some of the attributed functions to chitosans may in fact be due to CHOS. Despite these issues, there has been a recent interest in using these compounds to stimulate plant growth (Abu-Muriefah, 2013) and to modulate plant mineral concentrations (Chatelain et al., 2014).

The ability of roots to obtain micronutrients from the soil and to deliver these to the aerial tissues — including seeds — is essential to ensure that the shoot has the resources it needs to function effectively. However, plants need to control several steps during the journey from soil to seed, including uptake, transport, remobilization and storage. A better comprehension of the relative contribution of these processes, together with their overall coordination, is necessary for a more complete understanding of plant metal homeostasis and for the development of successful biofortification strategies. This Research Topic aims at addressing some of the most recent advances in micronutrient movement from soil to seed and to provide an overview of different approaches that can be used to generate micronutrient-efficient and biofortified plants. Here, we highlight some of the major points arising from these reports.

Submitted by Anabela Morais (ajmorais@porto.ucp.pt) on 2013-01-25T10:53:54Z No. of bitstreams: 1 AN1FrutasLegumesFlores-2012.pdf: 164585 bytes, checksum: 338de75688ef4ccab3ceba01f5243431 (MD5) Approved for entry into archive by Maria João Pinto (mjpinto@porto.ucp.pt) on 2013-01-28T10:25:07Z (GMT) No. of bitstreams: 1 AN1FrutasLegumesFlores-2012.pdf: 164585 bytes, checksum: 338de75688ef4ccab3ceba01f5243431 (MD5) Made available in DSpace on 2013-01-28T10:25:07Z (GMT). No. of bitstreams: 1 AN1FrutasLegumesFlores-2012.pdf: 164585 bytes, checksum: 338de75688ef4ccab3ceba01f5243431 (MD5) Previous issue date: 2012 N/A

O nemátode da madeira do pinheiro (NMP), Bursaphelenchus xylophilus, é o principal agente causal da doença da murchidão do pinheiro. Esta é uma enfermidade grave que afecta florestas de coníferas com uma elevada taxa de mortalidade. Presentemente não são conhecidos meios eficazes de combate à doença da murchidão do pinheiro, apesar da enfermidade ser conhecida e ser alvo de investigação há várias décadas. A complexidade desta doença, na qual vários mecanismos de patogénese parecem agir em simultâneo, contribui em grande parte para a inexistência de um tratamento eficaz, pelo que o aprofundamento do conhecimento da doença é fundamental. Neste trabalho usou-se SPME-GC/MS para estudar a modificação na composição de compostos de natureza volátil em caules de Pinus pinaster após inoculação com NMP. A componente volátil de caules inoculados mostrou ser significativamente diferente de caules controlo. Uma análise estatística multivariada de componentes principais (PCA) demonstrou uma completa separação dos 2 grupos.

Póster, [ES] La seca súbita del pino es una grave enfermedad que origina una elevada tasa de mortalidad en las masas de coníferas debido al ataque por el nemátodo de la madera del pino Bursaphelenchus xylophilus. Dado que este organismo fue recientemente introducido en Europa, es importante determinar el grado de susceptibilidad de las especies forestales autóctonas al mismo. En este trabajo hemos optimizado un test in vitro de susceptibilidad al nemátodo para ser empleado con un gran número de muestras vegetales. El test se basa en la capacidad de nematodos virulentos de atravesar secciones de 5 cm de longitud de ramillos jóvenes de pino de aproximadamente 2 cm de diámetro. El proceso de puesta a punto ha considerado el tamaño adecuado de recipiente, el sistema para la sujección de los ramillos en posición vertical, el volumen de agua de la base del ramillo y el sistema adecuado para evitar la deshidratación de la parte distal del ramillo tras la inoculación del nemátodo. También hemos dimensionado el sistema de cultivo del nemátodo en laboratorio para la producción en masa de grandes cantidades de inóculo, pasando del cultivo en tubos de ensayo a cultivo en contenedor. El test fue aplicado a ramillos de Pinus pinaster, pero puede ser adaptado a otras especies., [POR] A doença da murchidão do pinheiro é uma doença grave que afecta florestas de coníferas com uma elevada taxa de mortalidade, sendo causada pelo nemátode Bursaphelenchus xylophilus. Dado que este organismo foi recentemente introduzido na Europa, é importante determinar o grau de susceptibilidade de espécies florestais autóctones ao nemátode. Neste trabalho optimizou-se um teste de susceptibilidade para utilização num grande número de amostras. O teste baseia-se na capacidade de nemátodes virulentos atravessarem secções de 5 cm de ramos jovens, com cerca de 2 cm de diâmetro. O processo de optimização passou pela forja de recipientes de dimensões adequadas, criação de um modo de sustentar os ramos em posição vertical, optimização do volume de água onde a base do ramo fica mergulhada e criação de um modo de evitar a desidratação do topo do ramo após inoculação. O crescimento dos nemátodes em laboratório também passou por um scale-up para obtenção de nemátodes em grande quantidade, passando do crescimento em tubos de ensaio para sacos. O teste foi optimizado usando ramos de Pinus pinaster, mas pode ser adaptado a outras espécies., Agradecimientos ao Fundo Florestal Premanente, Instituto de Financiamento da Agricultura e Pescas I.P., Autoridade Florestal Nacional, Proder, DOCINIA, Predoc-INIA e MCIN-AGL-FOR-2010-18724 pelo financiamento.

Submitted by Anabela Morais (ajmorais@porto.ucp.pt) on 2012-01-27T10:21:31Z No. of bitstreams: 1 paperFLF2011.pdf: 931365 bytes, checksum: e657af264604cbc3c060e63e3e415eb2 (MD5) Made available in DSpace on 2012-01-27T11:04:36Z (GMT). No. of bitstreams: 1 paperFLF2011.pdf: 931365 bytes, checksum: e657af264604cbc3c060e63e3e415eb2 (MD5) Previous issue date: 2011 info:eu-repo/semantics/publishedVersion

The purpose of this study was to compare the response to infection with the pine wood nematode (PWN) Bursaphelenchus xylophilus between Pinus pinaster and Pinus pinea at an initial stage of the disease, three hours after inoculation. The PWN is the causal agent of pine wilt disease, in Portugal its main host is the maritime pine, P. pinaster, and its vector is Monochamus galloprovincialis. Currently there are no studies that describe the effects of nematode infection in plants at an early stage of the disease and with regards to the physiological and metabolic indicators of the disease response in the plants, there was a decrease of 10.9% of water content in P. pinaster (compared with trees inoculated with water) and 6.7% in P. pinea; in the study of total chlorophyll concentration, a decrease to about half of the control value was recorded for both species, but more pronounced in P. pinaster. An exploratory study was also made with gas chromatography, which showed that the volatile compounds produced were distinct between species, but not between control vs. nematode-inoculated plants.