Flower Bud Differentiation in Quercus suber L.

Background and Purpose: Cork oak (Quercus suber L.) is one of the most important forest species growing in the Western Mediterranean region. This investigation intends to assess the timing of flowering differentiation of cork oak and contribute to the deepening of the knowledge about the process of the sexual reproduction of the species. Materials and Methods: In 2010 four trees were selected (9, 14, 24, 25) from a plot of 25 trees located at Quinta da Serra, Portugal. A total of 240 buds were collected from these four trees, on three days (8, 14 and 23 March), from 4 branches per tree and 5 positions per branch for the assessment of meristem differentiation. Results: Meristem differentiation analysed on the sampling days revealed there were only vegetative structures by 8 March; a few male and female primordia on 14 March; and fully differentiated reproductive structures on 23 March. Conclusions: Flowering sex determination of cork oak occurs about one month before the flowering onset

Avaliação da expressão de genes relacionados com a susceptibilidade a Bursaphelenchus xylophilus, agente causal da doença da murchidão dos pinheiros (pine wilt disease) em Pinus pinaster Ait e Pinus yunannensis Franch

Tese de mestrado. Biologia (Biologia Celular e Biotecnologia). Universidade de Lisboa, Faculdade de Ciências, 2012A floresta constitui um bem precioso à escala mundial, do ponto de vista ecológico, paisagístico e económico. No entanto, nos últimos tempos tem-se registado um grave declínio de muitas espécies florestais, sendo em Portugal, o pinheiro bravo, Pinus pinaster Ait das espécies mais afetadas. Uma das principais causas, identificada nas últimas décadas, para este declínio, é o nemátode da madeira do pinheiro. O nemátode da madeira do pinheiro (NMP), Bursaphelenchus xylophilus, é um organismo microscópico que causa a doença da murchidão dos pinheiros “pine wilt disease”. Numa tentativa de diminuir as perdas resultantes da doença, o estudo da resistência do hospedeiro é uma das abordagens de investigação que se iniciou recentemente em Portugal, com o objetivo de melhorar a sua resistência e selecionar árvores com menor suscetibilidade à infeção. A identificação de genes, promotores e marcadores moleculares ligados à resistência à doença, que possam vir a ser mais tarde utilizadas na seleção assistida de genótipos com menor suscetibilidade ao NMP, poderá contribuir para acelerar os programas de melhoramento para a resistência a implementar para esta espécie. Nesse sentido, este trabalho teve como principal objetivo determinar os tempos mais relevantes, após inoculação com NMP, a utilizar para ulterior sequenciação em massa, de bibliotecas de cDNA de Pinus pinaster a a espécie Asiática Pinus yunnanensis, utilizada como controle de tolerância/ resistência para a comparação ulterior de transcritomas destas duas espécies em resposta à infeção com NMP. Foi também comparada a distribuição e propagação do nemátode no interior das duas espécies, após inoculação com NMP, em plantas de três anos, através de observações histológicas. Para determinação dos TAI (Tempos Após Inoculação) relevantes, em termos de expressão de genes candidatos de resistência a stresses bióticos, estudou-se a expressão diferencial dos seguintes genes: Thaumatin like protein, Endo-quitinase, Pinosylvin synthase, Superoxide dismutase-like protein e Allene Oxyde Cyclase, através da técnica Real-Time Polymerase Chain Reaction. As observações histológicas permitiram observar que os canais de resina têm maior diâmetro em Pinus pinaster do que em Pinus yunnanensis, foi possível também verificar que, após inoculação, há um aumento acentuado de inclusões de amido na espécie Mediterrânica, em comparação com a espécie Asiática, em que as inclusões não sofrem alteração de número depois da inoculação com NMP. Quanto aos TAI, pode-se concluir que os primeiros tempos após a infeção, respetivamente 6h e 24h são os tempos em que há uma maior expressão diferencial dos genes em estudo e, portanto, os que se elegem para ulterior sequenciação de bibliotecas de cDNA.The forest is a valuable resource on a global scale, for ecological, economical and landscape purposes. However, recently there has been a serious decline of many forest species, being the maritime pine, Pinus pinaster Ait the most affected species in Portugal. A major cause detected in recent decades for this decline is the pine wood nematode. The pine wood nematode (PWN), Bursaphelenchus xylophilus, is a microscopic organism that causes pine wilt disease. In an attempt to reduce losses caused by this disease, the study of host resistance is one of the research approaches that recently started in Portugal, aiming to improve their resistance and select trees with lower susceptibility to infection. The identification of genes, promoters and molecular markers linked to disease resistance, that can be later used in marker assisted selection of genotypes with reduced susceptibility to NMP may help to accelerate the breeding programs for resistance to be implemented for this species. Taking this into account, this study aimed to determine the most relevant times after inoculation with NMP to be used for subsequent sequencing of cDNA libraries of Pinus pinaster and Pinus yunnanensis an Asian species, used as control of tolerance / resistance for further comparison of transcriptoms for these two species in response to the infection with PWD. The distribution and spread of nematodes was also compared within the two species after inoculation of three years’ old plants with NMP, by histological observations. For the determination of relevant TAI (Time After Inoculation) gene expression of the following genes was studied: Thaumatin like protein, endo-chitinase, Pinosylvin synthase, Superoxide dismutase-like protein and Allene Oxyde cyclase using Real-Time Polymerase Chain Reaction.Histological observations allowed the observation that the resin ducts have a larger diameter in Pinus pinaster, than in Pinus yunnanensis. It was also possible to verify that, after inoculation, there is an increase of starch inclusions in the Mediterranean type, as compared with the Asian species, where the inclusions do not change in number after inoculation with NMP. Regarding the TAI, one can conclude that early times after infection, respectively 6h and 24h are the ones where a greater differential expression of the genes under study was observed and therefore they are chosen for subsequent sequencing of cDNA libraries

Microbiome Associated with the Mycangia of Female and Male Adults of the Ambrosia Beetle Platypus cylindrus Fab. (Coleoptera: Curculionidae)

The ambrosia beetle Platypus cylindrus is a major cork oak pest in Portugal. Beetles have different roles in host tree colonization and are equipped with specific structures (mycangia) for fungal transportation. The information on bacterial composition associated with mycangia is scarce. The bacterial community present in the mycangia of P. cylindrus male and female beetles collected from cork oak galleries was investigated. Mycangia anatomical structure was also explored using histological and 3D imaging techniques to highlight evidence of biological sexual dimorphism. A diverse bacterial community with few gender-specific bacteria was shown and histology revealed connections linking external and internal tissues only in females, providing the first insights into sexual differentiation for bacteria in a Platypodinae beetle species.The ambrosia beetle Platypus cylindrus Fab. (Coleoptera: Curculionidae) is a major cork oak pest in Portugal. Female and male beetles have different roles in host tree colonization and are both equipped with prothoracic mycangia for fungal transportation. Despite a known beneficial role of bacteria in ambrosia beetles, information on bacterial composition associated with prothoracic mycangia structures is scarce. Bacterial community from mycangia of P. cylindrus male and female beetles collected from cork oak galleries was investigated by means of 16S metagenomics. Mycangia anatomical structure was also explored with histological techniques and X-ray computed microtomography to highlight evidence supporting biological sexual dimorphism. A bacterial community with highly diverse bacterial taxa with low abundances at the genus level was revealed. Lactobacillales, Leptotrichia, Neisseria, Rothia, and Sphingomonadaceae were significantly more abundant in males, while Acinetobacter, Chitinophagaceae, Enterobacteriaceae, Erwiniaceae, Microbacteriaceae, and Pseudoclavibacter were more abundant in females. Additionally, a core bacteriome of five genera was shared by both sexes. Histological examination revealed visible connections linking external and internal tissues in females, but none in males. Overall, these results provide the first insights into sexual differentiation for bacteria in a Platypodinae beetle species, identifying key patterns of bacteria distribution in the context of beetle ecology and functional behavior.info:eu-repo/semantics/publishedVersio

Corema album (L.) D. Don Phenological Growth Stages according to Extended BBCH Scale

The wild dioecious plant Corema album, endemic to the Atlantic coast of the Iberian Peninsula, has potential to become a new crop and to integrate the berry fruit market. Due to its potential, the aim of this study was to propose a BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemical Industry) scale for the species. Based on field observation, the principal growth stages were described and sequentially established. Photographs and stereomicroscope acquisition software were used to illustrate the phenological stages of male and female plants. The scale includes seven principal stages starting with bud development (stage 0), followed by leaf development (Stage 1), main stem elongation (Stage 3), inflorescence emergence (Stage 5), flowering (Stage 6), fruit development (Stage 7) and ending with fruit maturation (stage 8), with mesostages for male and female inflorescence (stage 5) and flower development (stage 6). Through field observations carried out in plants in different growth conditions, the proposition of this extended BBCH scale was made, to have a standardized system for Corema album phenological stages. This study will have an application especially in fields of agronomy and plant breeding and will also be a stepping stone for the inclusion of this species as a novelty crop in a nearby futureinfo:eu-repo/semantics/publishedVersio

Comparing Intraspecific Aggressiveness in

Phytophthora cinnamomi is a major plant destructive pathogen with a wide range of hosts and is considered one of the main causes of Quercus spp. decline in the Southwest of the Iberian Peninsula. This study compares two inoculation tests, using simple and fast methodologies, in order to select the most aggressive isolate to use in future Quercus suber inoculation experiments. To evaluate P. cinnamomi intraspecific variability, cork oak excised shoots were inoculated with five isolates, obtained from Q. suber, Quercus rotundifolia and Castanea sativa stands. These isolates were used for in vitro inoculation of a Trifolium subterraneum cultivar available in Portugal in order to assess its usefulness as a "model plant" in rapid screening tests. This study revealed intraspecific variability of P. cinnamomi isolates to cause lesions in Q. suber excised shoots and in the number of T. subterraneum developing lesions on stem and leaves. However, there was no correspondence between the aggressiveness of the isolates in subterranean clover and in the cork oak. Only one isolate showed consistency in aggressiveness regardless of the host species. In conclusion, T. subterraneum is not a good "model plant" for the evaluation of P. cinnamomi isolates aggressiveness

Indice de qualidade do planeamento em implantes de próstata

Este estudo tem como objectivo a avaliação dos índices de qualidade nos implantes de braquiterapia prostática com sementes l125, em todos os doentes tratados com a técnica transperineal, no Instituto Português de Oncologia de Lisboa Dr. Francisco Gentil, EPE, desde Dezembro de 2007 a Abril de 2009

Phenolic Compounds Regulating the Susceptibility of Adult Pine Species to Bursaphelenchus xylophilus

Pine wilt disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, is one of the most destructive diseases in trees of the genus Pinus and is responsible for significant environmental and economic losses in North America, Eastern Asia, and Western Europe. However, pine species are not equally affected, with some being tolerant/resistant while others are susceptible to nematode infection for reasons still unclear. The present study aims to investigate differential chemical responses of susceptible and tolerant/resistant pine species shortly after nematode infection by characterizing the phenolic profiles of adult Pinus sylvestris, Pinus pinaster, Pinus pinea, and Pinus halepensis. HPLC and LC-MS were used to identify and quantify the pine´s phenolic compounds: gallic acid, ferulic acid, taxifolin, rutin, resveratrol, (+)-secoisolariciresinol, (−)-epicatechin, protocatechuic acid hexoside, gallic acid hexoside, ferulic acid glucoside, quercetin hexoside, and two unidentified compounds (#A and #B). Prior to infection, we could not differentiate between nematode-tolerant/resistant and susceptible adult pine species based on their constitutive phenolic compounds. In the presence of the PWN, the phenolic profile allowed for a noticeable separation of the PWN-tolerant/resistant P. halepensis from the susceptible P. sylvestris, contrasting with a more homogenous response from P. pinea and P. pinaster. Observations on P. halepensis suggest that taxifolin, resveratrol, and rutin may have an active role in protecting against B. xylophilus, possibly in conjugation with other biochemical and anatomical characters. We emphasize the importance of studying pine tolerant/resistance on adult trees, and not on excised branches, saplings, or seedlings to accurately simulate the nematode–pine host interactions occurring under natural conditions

Phenolic Compounds Regulating the Susceptibility of Adult Pine Species to <i>Bursaphelenchus xylophilus</i>

Pine wilt disease (PWD), caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, is one of the most destructive diseases in trees of the genus Pinus and is responsible for significant environmental and economic losses in North America, Eastern Asia, and Western Europe. However, pine species are not equally affected, with some being tolerant/resistant while others are susceptible to nematode infection for reasons still unclear. The present study aims to investigate differential chemical responses of susceptible and tolerant/resistant pine species shortly after nematode infection by characterizing the phenolic profiles of adult Pinus sylvestris, Pinus pinaster, Pinus pinea, and Pinus halepensis. HPLC and LC-MS were used to identify and quantify the pine´s phenolic compounds: gallic acid, ferulic acid, taxifolin, rutin, resveratrol, (+)-secoisolariciresinol, (−)-epicatechin, protocatechuic acid hexoside, gallic acid hexoside, ferulic acid glucoside, quercetin hexoside, and two unidentified compounds (#A and #B). Prior to infection, we could not differentiate between nematode-tolerant/resistant and susceptible adult pine species based on their constitutive phenolic compounds. In the presence of the PWN, the phenolic profile allowed for a noticeable separation of the PWN-tolerant/resistant P. halepensis from the susceptible P. sylvestris, contrasting with a more homogenous response from P. pinea and P. pinaster. Observations on P. halepensis suggest that taxifolin, resveratrol, and rutin may have an active role in protecting against B. xylophilus, possibly in conjugation with other biochemical and anatomical characters. We emphasize the importance of studying pine tolerant/resistance on adult trees, and not on excised branches, saplings, or seedlings to accurately simulate the nematode–pine host interactions occurring under natural conditions

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved