22 March: Eva Forsgren

Symbionts as modulators of honeybee health: Lactic acid bacteria and foulbroods

Eva Forsgren

Department of Ecology, Swedish University of Agricultural Sciences, PO Box 7044, SE-75007 Uppsala, Sweden

Lactic acid bacteria (LAB) are recognized beneficial host-associated members of the microbiota of humans and animals. Yet, LAB-associations of invertebrates have been poorly characterized and their functions remain obscure. It has recently been shown that honeybees possess an abundant, diverse and ancient LAB microbiota in their honey crop, defending them against microbial threats, such as the bacterial brood diseases American (AFB) and European foulbrood (EFB). We used inhibition assays on agar plates to investigate the effects from honey bee LAB on the growth of the causative agents of the two foulbrood diseases, Paenibacillus larvae and Melissococcus plutonius. Furthermore, we used honey bee larval bioassays to investigate the effect from LAB supplemented feed on AFB and EFB infection in vivo. We could conclude that the honeybee LAB microbiota has an inhibitory effect on both foulbroods preventing individual larvae from fully developed and lethal infections. Work to identify the active inhibitory compounds involved is in progress and will be discussed.

6 March: Stefan Vidal

The hidden world of endophytic fungi mediating plant-insect interactions

Stefan Vidal

Georg-August-Universität Göttingen, Department für Nutzpflanzenwissenschaften
Abteilung Agrarentomologie


Fungal endophytes (i.e. fungi that live internally within the tissues of their host plant without causing visible signs of infection) are ubiquitous associates of higher plants, found in virtually every organ from every plant species examined so far. In the past research concentrated on clavicipitaceous endophytic fungi that are vertically transmitted (via seeds) and systemically associated with grasses. These fungi are thought to interact mutualistically with their host plants mainly by the production of secondary compounds, including alkaloids, which benefit plants by increasing their competitive ability and resistance to biotic and abiotic stress factors. However, the vast majority of fungal endophytes form internal localized infections in foliage, roots, stems, and bark, and are horizontally-transmitted via spores. To date the interactions between these omnipresent unspecialized endophytes in their host plants and herbivores, feeding on these plants, remain largely unexplored.

We used a widespread and non-specialized genus of endophytic fungi, Acremonium spp., to test, whether these fungal endophytes interact with their host plants, and thus mediating effects on higher trophic levels. Using different host plant-endophyte-herbivore-systems we found consistent pattern with regard to these interactions: Colonisation of endophytes proved to be antagonistic towards herbivorous insects, but plants did not suffer from endophyte growth. Herbivorous larvae experienced higher mortality when feeding on plants colonised by the fungi, and negative effects translated even into the next generation. On the other hand, plants colonised by an endophyte were more attractive for adults, stimulating oviposition, resulting in a paradoxon of “mother’s don’t know best”. Explanation for this paradoxical behaviour will be discussed.

There is now ample evidence that endophytes induce changes in the metabolism of their host plants mediating herbivore preference and performance pattern. Potential applications for using these endophytes in plant protection strategies will be outlined.

8 february: Michael Stoltze

Nature and Biodiversity in Denmark - status and outlook 2013

How can Denmark reach the EU and UN goal of halting the loss of biodiversity before 2020? This lecture will focus on the results of the recent efforts to protect and restore nature and biodiversity in Denmark. What are the present challenges and what is the outlook?

About the speaker
Michael Stoltze is a biologist from UCPH with specialty in African caddis flies and PhD thesis about butterflies in Denmark. Since 2008 he has been an independent author, commentator, speaker, debater and photographer as owner of the company Natur og Idé ('Nature and Idea'). Michael Stolze is a writer and reviewer at the newspaper Kristeligt Dagblad and he edits the blog "Stoltze" about nature, climate and the environment for the newspaper Politiken. For a number of year, Michael Stoltze worked at Danmarks Naturfredningsforening (Danish Society for Nature Conservation) where he was engaged in conservation and politics of nature. In addition he has published a number of books and articles about Danish butterflies and the nature of Denmark.

7 December: Niels Jacobsen

Changing habitats and hybridization i.e. recombination are the driving forces in plant evolution 

Niels Jacobsen 
 
Department of Plant and Environmental Sciences, Section of Organismal Biology, University of Copenhagen 

Studying plants and populations in the field will invariably lead to the discovery of hybrids. It will also be found that hybrids occur more frequently in some plant groups than in others, and these hybrids behave differently in the different plant groups. 

In order for hybrids to be formed, it is necessary for them to “meet” or at least be within pollination distance of one another. 

In stable plant associations hybrids are found less frequently than in unstable plant associations. You could say that habitat changes act as a promoter and hybridization acts as an operator for evolution. 

Besides studying these phenomena in nature, they can be studied with a much greater advantage in our cultivated plants. The study of the origin and evolution of our cultivated plants (ornamentals as well as crop plants) provides a mosaic of scenes of how the evolution of plants has taken and is still taking place. 

The talk will be illustrated by a wide range of examples of flowering plants including among others genera such as Crocus, Cryptocoryne, Lilium, Hordeum, and Narcissus.

9 November: Henrik Lütken

Three biotechnological methods to develop compact ornamentals

Henrik Lütken, Ph.D, Associate Professor

Department of Plant and Environmental Sciences, Copenhagen University


Plant height is a quality parameter of primary importance in a large number of economically important ornamental plants. Consumers prefer short, compact plants with good keeping quality and ornamental value. In addition, compact plants tolerate mechanical handling and transport far better than more elongated plants. Furthermore, smaller plants require less space in expensive production facilities, are easier to handle, have reduced transportation costs and advantages for retailers. Thus, compact plants are preferred throughout the whole production and postharvest chain increasing profit in production and distribution. Currently, the feature compactness is obtained through the extensive utilization of chemical growth retardation targeting gibberellin (GA) response, e.g. chlormequat, daminozide or paclobutrazol. The number of approved growth retardation compounds is highly dependent on the country of production. For example, application of paclobutrazol and daminozide is no longer approved in many European countries. In my talk I’ll present and discuss three biotechnological methods; a non-GMO, a cisgenic and a GMO approach to develop compact ornamentals exemplified by Kalanchoë. In the non-GMO method unmodified strains of the soil-born bacterium Agrobacterium rhizogenes are used for transformations and this method is not considered as a GMO method in the European Union and Japan. Using this method compact plants are produced by the insertion of T-DNA containing root loci (rol) genes from A. rhizogenes into potted plants. Infection of plants by A. rhizogenes induces the growth of hairy-roots at the infection sites due to the insertion of four rol-genes, rolA, rolB, rolC and rolD. In many ornamental plants, rol-genes have been successfully used, causing reduced plant height, short internodes and reduced apical dominance. The cisgenic approach involves KNOX (KN) homeotic proteins that generally are involved in stem meristem differentiation. These genes can be used to modify plant architecture by both overexpression and silencing. The compact plants derived from this method often show a higher degree of branching and darker green colour due to elevated chlorophyll content. The latter is a highly desired feature in the ornamental plant industry. In the GMO approach the Short Internodes (SHI) gene from the model plant Arabidopsis thaliana is ectopically expressed. The SHI gene encodes a transcription factor belonging to the SHI–gene family, where the members act by gene dose-effect and are partially redundant. Overexpression of the genes leads to compact plants with a phenotype of mutants defective in GA biosynthesis and response. Although flowering can be delayed it can be restored by application of minute amounts of GA. When expressed in ornamentals compact inflorescences were in particular observed.

26 October: Satu Ramula

A demographic approach for plant invasions

Dr. Satu Ramula

Biodiversity Unit, Lund University, Sweden 

 

Invaders generally show better individual performance than non-invaders and therefore, species traits could potentially be used to predict species invasiveness outside their native range. However, comparative studies have usually correlated traits with the invasiveness status of species, while few studies have investigated traits explicitly in relation to population performance in terms of the long-term population growth rate. Using data on multiple populations of an invasive herb in its invaded range, I demonstrate that the measures of a single or a few plant traits do not necessarily reflect population performance and invasiveness correctly because only some fitness-related plant traits map directly into the long-term population growth rate. Therefore, a demographic approach that takes the whole life-cycle into account is required. I illustrate that this demographic approach provides a tool for identification of the demographic processes with the greatest impact on population growth rates, enabling a better understanding of the population dynamics and potential management strategies for invasive plant species.

12 October: Gaia Luziatelli

 
The hidden treasures of the Andes: future possibilities for the promotion of under-utilized Andean root and tuber crops in Bolivia.

Gaia Luziatelli, PhD student

Department of Plant and Environmental Sciences, Copenhagen University

In the Andean Region of Bolivia farmers cultivate more than 4,000 landraces of native potatoes, however, the majority of them never reach the market. This situation is shared also by other Andean root and tuber crops which, despite the high nutritional values, medicinal properties and low input requirements, are being substituted by other non-indigenous crops. Solutions for making Andean Roots and Tubers Crops (ARTCs) more profitable for the farmers and better accepted by the urban population might be offered by gourmet restaurants and organic markets.

In my research I use a combination of ethno-botanical methods, market studies and agronomic field trials. The first two approaches serve to understand the problems faced by the farmers in the cultivation and commercialization of ARTCs, as well as how to meet the requirements of gourmet restaurants and organic markets. The field trials assess different organic treatments on native potatoes in the region of Colomi, in the Cochabamba Department.

The results of the study will hopefully contribute to the sustainable production of Andean roots and tuber crops in Bolivia, combined with the promotion of local and international markets.

22 June: Janna Barel, Ilona Knaapen & Janneke Koster

Host-plant interaction of Phyllotreta nemorum and Barbarea vulgaris

Janna Barel, Ilona Knaapen & Janneke Koster

Wageningen UR, Laboratory of Entomology, The Netherlands

The yellow striped flea beetle Phyllotreta nemorum is an oliphagous beetle, attacking only a number of cruciferous host plants, including Sinapis vulgaris, Raphanus raphanistrum, Lepidium draba, Brassica nigra and cultivated radish (Raphanus sativus). The flea beetle is usually susceptible to chemical defenses of the G-type of Barbarea vulgaris. However in Denmark some populations are found to spread their host range to B. vulgaris. Currently the entomology group is trying to unravel the genetics behind the resistance of P. nemorum. Ilona Knaapen will investigate whether the resistance in the different populations of P. nemorum is caused by genes at the same or at different loci. Additionally field studies have shown that a surprisingly low amount of flea beetles are resistant. Janneke Koster will examine the resistance frequency to investigate the changes over time over the whole flea beetle season and the parasitic rate and choice between resistant and non-resistant beetles. Furthermore Janna Barel will look if competition between resistant and non-resistant beetles can be the cause of the low frequency of resistant beetles on Sinapis plants. She is testing the overall completion on radish plants as well as potential differences in larval development duration.

25 May: Maria Ignatieva

Plant material for urban landscapes in the era of globalization: roots, challenges and innovative solutions  

Maria Ignatieva, Professor in Landscape Architecture

Department of Urban and Rural Development, Swedish University of Agricultural Sciences, Uppsala, Sweden 

The globalisation process has not only influenced politics and economies but social and cultural life of modern society. Globalisation in landscape architecture poses a threat of homogenisation, the creation of ‘placeless’ design, and the loss of the uniqueness of the place. Usually globalisation is associated with westernisation and an acceptance of the western vision of life and cultural preferences. Today the world has accepted the Euro-American consumer’s vision with its ’routine modernism‘ of skyscraper architecture in the Central Business Districts, suburbanisation, particular landscape architecture styles, and standardised plant and construction materials. In this presentation I will concentrate on a discussion of global plant material in urban landscapes.

Each style in the history of planting design offered a special palette of plants that contributed to the Western generic ‘pool’ of fashion plants. English Picturesque, Victorian and Edwardian gardens gifted Western civilisation with several clichés such as pastoral landscapes of lawn with scattered groves and specimen trees, rock gardens, flower and carpet bedding, “wild garden” and perennial borders with an associated wide range of plant material. This plant “pool” reflected garden traditions and discoveries of new colonies and an interest in the plant world. Victorian Botanical gardens were responsible for creating the list of purposely “chosen” plants from of different historical and geographical origins. Edwardian gardens used a blend of different styles for consumption in a growing and demanding horticultural market. By the end of the Edwardian era the “core” of plants which are grown today in commercial nurseries all around the globe was almost completed. Some authors believe that UK pushed gardens to be “the main contact zones for cultural exchange between Britain and the world”. Plant material plays an extremely important role in modern globalised consumer culture. New countries which have recently entered the market system such as Russia, China and the United Arab Emirates use global plant material as an important symbol of Western landscapes and for creating ‘familiar’ comfortable landscapes which can attract global investments in their economies. Globalised plant material leads to homogenisation of our cities and towns.

Western countries (Europe, USA, Australia and New Zealand) are the main contributors to the global plant material and general vision of consumerism and global culture. Nevertheless these countries have experienced ecological and social crisis and have to search for new alternatives to existing unsustainable landscape practice based on global cultural preferences. Today these countries are suggesting new planting design directions based on the knowledge of plant communities, hence respecting local nature and culture. At the beginning of the 21st century Western countries should understand the importance of their mission in offering a new planting design “democratic” vision that demonstrates ecological responsibility and integrity.

11 May: Juan Pablo Rodriguez

Fruit shattering character in semi-domesticated Chenopodiaceae species: case example of an Andean grain Chenopodium pallidicaule

Juan Pablo Rodriguez, PhD student
 
Department of Agriculture and Ecology / Crop Science, University of Copenhagen

Seed shattering is one of the main characters in semi-domesticated cultivated species. The fruit shattering reduces good yields compared to rice and other long time domesticated cereal crops. Among the Chenopodiaceae species it is known that the Andean Chenopodium quinoa Willd. was domesticated about 7000 years ago, and in this species the achenes are tightly compacted in an infructescence at the top of the main stem (panicle).  Worldwide quinoa is appreciated for its high nutritional value; however, there is a close relative species Chenopodium pallidicaule Aellen (cañahua or cañihua), which remains as a semi-domesticated plant. This cañahua is cultivated in the most difficult agricultural highland rural communities in Bolivia and Peru and offers highly valuable traits as low temperature tolerance; and above all the achenes are free from saponins. This character makes it more easy to prepare for food than the quinoa. One main problem with cañahua is the early fruit shattering behaviour shortly after flowering. The harvesting has to be carried out when the ripe achenes are beginning to disperse. For the farmers this is an indication of when to start harvesting. When this aspect is not taken into account, the loss of achenes can reach 30%. In my trial I have started examining a local Bolivian cañahua cultivar in Taastrup. The plants are recorded and surveyed at each developmental stage since they were sowed in pots. A more careful study of the shattering of achenes will be determined in the infructescence after the flowering stage. The shattered nuts will be collected according to physiological maturity stage. And the abscission layer at the flower-pedicel junction in the local cultivar will be examined. A more precise estimation of how many nuts are shattered during the growing season will provide better knowledge finding the optimal time to harvest plants in relation to plant development.

27 April: Rikke Bagger Jørgensen

 

Are fast adaptive changes in plants a remedy against the changing climate?

Rikke Bagger Jørgensen, senior scientist

Dept. Chemical and Biochemical Engineering, DTU

These studies from wild and cultivated Brassica and Hordeum species aim to reveal, if plant populations can undergo fast microevolution, when they are subjected to strong selection from abiotic stressors - temperature, CO₂, ozone - over a range of progressing plant generations.

Plants are facing an increase in temperature, elevated atmospheric carbon dioxide and other greenhouse gases. Recent projections assume an increase in average global temperature of up to 5 ^°C, which would have an impact on plant populations. Where the plastic responses of a population cannot compensate for the stressful changes in the environment, only evolutionary adaptation can prevent wide-ranging declines in fitness and counter the increased risk of extinction. Especially for slowly migrating populations of plants, where migration may fail to cope with the speed of environmental change, adaptation responses will have a major importance. We present the results of a number of ‘laboratory natural selection experiments’ applying five future climate scenarios, where the effects were investigated over four plant generations. In the climate scenarios CO₂, temperature and ozone concentrations were changed (as multifactor or single factor changes), and populations were allowed to adapt freely by fertility- and mortality distributions. Biomass and reproductive output were recorded over generations and molecular markers in the unselected F0 generation compared to the selected F4 generation.

The three species studied reacted differently to the multigenerational selection experiment suggesting differences in adaptive potential.

13 April: Nina Rønsted

Phylogeny predicts chemical diversity and potential medicinal activity of plants: evidence from Amaryllidaceae
 
Nina Rønsted, Associate Professor

Botanical Garden and Museum, Natural History Museum of Denmark

During evolution, plants and other organisms have developed a diversity of chemical defence lines, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive approach enabling more efficient selection of plants for traditional medicine and lead discovery. However, this relationship has rarely been rigorously tested and the potential predictive power is consequently unknown.

We produced the largest ever phylogenetic hypothesis for the medicinally important plant subfamily Amaryllidoideae (Amaryllidaceae) based on parsimony and bayesian analysis of nuclear, plastid and mitochondrial DNA sequences of over 100 species. We tested if alkaloid diversity and central nervous system related activities are significantly correlated with phylogeny.

  

Several genera are non-monophyletic emphasizing the importance of using phylogeny for interpretation of character distribution. Alkaloid diversity and in vitro central nervous system related activity are significantly correlated with phylogeny. This has implications for the use of phylogenies to interpret chemical evolution and biosynthetic pathways, to select candidate taxa for lead discovery, and to make recommendations for traditional use and conservation priorities.

23 March: Inger Kappel Schmidt

Plant responses to climate change in contrasting heathland ecosystems

Inger Kappel Schmidt

Dept. of Forest and Landscape Ecology, Forest and Landscape, Copenhagen University

Climate change affects the performance of species in different ways and potentially it changes community composition. In large scale climate manipulation experiments across Northern Europe, we studied the sensitivity of heathland species to climate during 12 years. A naturally occurring outbreak of heather beetles (Lochmaea suturalis Thompson) defoliated the heather at one site. This enabled studies of the climate sensitivity of adult plants as well as during the regenerative phase. We found the strongest effects of climatic change related to extreme events and biotic interactions resulting in a replacement of C. vulgaris with species connected to acid grassland. The transition was altered with extended drought periods and warming due to altered impact by the heather beetles and due to lower recruitment. The future climate with higher minimum temperatures and extended drought periods and with increased impact of herbivores and diminished window for regeneration may have major impact on the distribution of C. vulgaris heathlands and the area of heathlands in Europe may decrease further due to invasion by grasses and trees.

9 March: Sanna Huttunen

Phylogeny of moss order Hypnales - current state of knowledge and future challenges

Sanna Huttunen

Department of Biology, University of Turku, Finland

The Hypnales are the largest moss order comprising circa 4200 species, i.e. 1/3 of all mosses. Phylogenetic reconstruction of the group has proven to be difficult due to rapid radiation at an early stage of their evolution, but the most studies applying molecular systematic methods favor its position as a crown clade in the phylogeny of mosses. Within the order, however, relationships among groups have remained poorly resolved. The most recent phylogenetic inference is based on four sequence regions, namely, nuclear ITS1-5.8S-ITS2, plastid trnL-F and rps4, and mitochondrial nad5, for 122 Hypnalean species and 34 species from closely related groups. Tree topologies resolve the order as monophyletic, although monophyly, as well as the backbone nodes within the Hypnales, gained significant support only under Bayesian inferences. The phylogenetic tree differs only in few details from recent classifications, but familial relationships especially among the apical crown clade within the Hypnales were mainly unsupported. Ancestral distribution based on Bayesian dispersal-vicariance analysis support a Gondwanan origin of the Hypnales and subsequent geographical radiation in the area of the former Laurasian supercontinent. Reconstruction of historical biogeography is congruent with mainly tropical and Gondwanan distributions in the sister groups Hypnodendrales, Ptychomniales, and Hookeriales, and with the dating for the oldest pleurocarp and Hypnalean fossils. Scattered fossil data, unique character combinations in some of the fossil pleurocarps and lack of a well-supported phylogeny, however, still hamper testing diversification events using molecular dating. In the presentation I will summarize current knowledge on the evolutionary history and relationships among the Hypnales and present an overview of the recent fossil data on pleurocarpous mosses. In light of these two sources of the information I aim at discussing evolution of the Hypnales and point out potential directions for future research.

24 February: Tamara van Mölken

Three-way interactions between pathogens, plants and herbivores: consequences for herbivore feeding, disease development and plant fitness. 

Tamara van Mölken 

Department of Agriculture and Ecology, University of Copenhagen, Denmark. 

Under natural conditions plants are often simultaneously exposed to pathogen attack and damage by insect herbivores. As a consequence of sharing the same host plant, interactions between pathogens and herbivores are bound to occur. The plant plays a central role in mediating such interactions, whereby pathogen induced changes in the host plant can affect herbivory and vice versa. Mechanisms underlying these effects include pathogen induced changes in: secondary metabolite levels; nutritional value; plant volatile emissions; and crosstalk between defence pathways. In turn, these biochemical changes may affect herbivore feeding and behaviour. Given that both pathogens and herbivores can impair plant performance, reciprocal effects between pathogens and herbivores are expected to result in altered plant growth and reproduction. To gain more insight into the ecological implications of pathogen infection for plant-herbivore interactions, we need a better understanding of the tripartite interactions between plants originating from wild populations and their naturally associated pathogens and herbivores. Barbarea vulgaris is well studied for its chemical defences against a range of herbivores. This herbaceous plant is susceptible to Phyllotreta nemorum flea beetles and the oomycete pathogen Albugo candida which both occur in wild B. vulgaris populations. In a series of experiments we have addressed the following questions: (i) does infection with the oomycete have an effect on flea beetle induced changes in plant nitrogen, glucosinolate and saponin levels; (ii) what are the effects of the pathogen on herbivore preference, consumption and fitness; and (iii) how do biochemical changes and variation in pathogen and herbivore damage affect plant growth, development and fitness?