Aphid wired to the Electrical Penetration Graph. Photo: Cecilia Ström
When a herbivore attacks a host plant, a defence response is initiated, triggered either by the herbivore or by the plant itself. Knowledge about the mechanism behind such responses are used to develop pest management strategies that align with UN-sustainability goals for crop protection. In a new article published in the journal Plant Physiology, a UPSC-team led by Karen Kloth and Benedicte Albrectsen questioned the role of a cell wall modifying enzyme for defence responses to aphid attacks.
In their experiments, the researchers investigated the feeding behaviour of an insect, the so-called green peach aphid, on plant cell walls of thale cress (Arabidopsis thaliana). The aphid manoeuvres its needle-like mouth through the cell wall matrix to reach the phloem, a transport tissue in plants transporting sugars from the leaves to the roots. It feeds on the sugar-rich phloem sap. This penetration through the cell wall damages the cell wall to a certain extent. The researchers wanted to test the hypothesis that plant defence responses are the result of certain cell wall components that break of cell wall carbohydrate pectin, in response to the aphid penetration.
Their study focused on the effect of a special pectin modifying enzyme, called Pectin Acetylesterase 9 (PAE9), which has not been studied in this context up to now. They investigated mutants of the model plant thale cress, which have been modified to shut off PAE9. Their experiments showed that PAE9 is important for general defence reactions. The mutants that did not contain the PAE9 enzyme initially produced less defence hormones and metabolites. These defence compounds seem to make the plant more resistant to aphids. In the mutants, the aphids started phloem feeding earlier than in control plants with normal levels of defence compounds. However, with time, levels of defence compounds recovered to control levels also in the mutants. The researchers concluded therefore that PAE9 act as a front door guard that delays and initially fends off intruding aphid pests.
The article was published in Plant Physiology:
Karen J. Kloth, Ilka N Abreu, Nicolas Delhomme, Ivan Petřík, Cloé Villard, Cecilia Ström, Fariba Amini, Ondřej Novák, Thomas Moritz, Benedicte Riber Albrectsen (2019). PECTIN ACETYLESTERASE9 Affects the Transcriptome and Metabolome and Delays Aphid Feeding. Plant Physiology, Oct 2019: doi.org/10.1104/pp.19.00635
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Last week, 34 PhD students and Postdocs from UPSC visited the Viikki Plant Science Centre (ViPS) in Helsinki. Within two days, they got an insight into the research that is performed at ViPS, presented their own research and visited the facilities. This was the second joint meeting between UPSC and ViPS.
Arriving on Wednesday afternoon, the programme started with a joint dinner at the Brewery of Suomenlinna in Helsinki. The next day focussed on research. After an introduction to the centre by its director Paula Elomaa, the group from UPSC got an insight into different research projects at ViPS and every one of them presented their own research in a two-minute-long flash talk.
The afternoon on Wednesday started with the ViPS Science Fair. PhD students and postdocs from ViPS research groups presented their projects in form of posters to master students. By joining the Science Fair, the visitors from UPSC got an overview about the broad range of research projects done at ViPS. The day finished with a UPSC/ViPS get-together and one-on-one meetings with ViSP group leaders. Several PhD students and postdocs used this opportunity and appreciated those personal meeting.
On Friday morning, the PhD students and postdocs from UPSC could visit different research facilities. They were interested to see how things are organised at ViSP and got tours to the greenhouse, the phenotyping facilities, the metabolomics unit, the sequencing service and some other labs. The group flew back to Umeå in the afternoon.
Two years ago, the PhD students from the Doctoral Programme in Plant Sciences that is associated with ViPS visited UPSC. The visit to Helsinki this year was a follow-up meeting that shall help to strengthen the collaboration between the two plant research centres.
In case of threats plants cannot run away but they do have a defence comparable to the humane immune system. This plant immune system helps them to fight off for example microorganism attacks. By so-called defence priming the plant immune system can be trained to memorize threats and act more effective against them in future. Solid knowledge about this mechanism is still scattered. A group of UPSC researchers lead by Benedicte Albrectsen tried the first systematic approach and published a meta-analysis on defence priming in plants focusing on thale cress.
How the plant immune system memory works is not yet fully understood but it is known that different molecular mechanisms act. The whole process is triggered by external stimuli, so-called priming agents. Priming agents can be living organisms, like microorganism and arthropods or chemical compounds, like vitamins and plant hormones. These triggers can induce the priming process in all kind of plant tissues and developmental stages. During the so-called priming phase, the plant gets stimulated by a priming agent in absence of actual threats. It accumulates compounds that later play a role in the defence. The primed status is durable, does not decrease the plants fitness and can be even passed on to the next generation.
Defence priming is a known phenomenon but for applying it widely in agriculture further knowledge is needed. In the current study the researchers analysed more than 240 studies on thale cress (Arabidopsis thaliana). The group tried to find patterns in plant responses to stress and identify possible relationships between priming agents and antagonists, like pathogens or herbivores. With their analysis they clearly show that defence priming enables the plant to withstand subsequent danger better than un-primed conspecifics. It helps the plant to defend itself faster and more effective the next time the same stress occurs.
The elaborate data comparison also allowed the researchers to identify potential players in the priming challenge. “We present a list of potential priming agents that we suggest could improve plant resistance properties in the future”, explains Benedicte Albrectsen. “The list includes microorganisms and organic chemical compounds with varied effect”. They showed that several compounds, like fungi and vitamins act as strong priming agents in thale cress whereas the influence of herbivores on the priming effect seems rather week.
This publication supports the theory that defence priming has an effect. It emphasizes that on the long run it can be used to enhance thread-resilience also in crops. The current agricultural systems are facing severe challenges including increasing demands, higher costs, and a changing climate. Defence priming has the potential for raising crop productivity with little environmental risk and this could help to move towards a more sustainable agriculture.
The work was recently published in Scientific Reports:
Westman SM, Kloth KJ, Hanson J, Ohlsson AB & Albrectsen BR (2019). Defence priming in Arabidopsis – a Meta-Analysis. 9:133309 (doi.org/10.1038/s41598-019-49811-9)
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[2019-09-02] Last week, the SPPS (Scandinavian Plant Physiology Society) Congress took place at Elite Hotel Mimer in Umeå. During three days, members of the society discussed actual topics in plant physiology, several prizes were officially handed out and the society held its General Assembly and elected the new SPPS Council. A special highlight during the conference was the technically advanced excursion to the Field Research Site “Rosinedal” that was even mentioned in the local newspaper.
The Scandinavian Plant Physiology Society is organising every second year its main meeting, the SPPS Congress. The focus of this international meeting is on exchanging and discussing knowledge about actual topics within the field of plant physiology. Internationally renowned researchers in the field are invited to present their research in parallel to Scandinavian plant physiologists. During the general assembly of the society, the new council was elected with Christiane Funk, Professor at the Department of Chemistry at Umeå University and associated group leader at UPSC, as new president.
During the congress, SPPS handed out six different prizes to award outstanding achievements of plant scientists, located in one of the Nordic countries. Three of this year’s awardees are affiliated with the UPSC: Karin Ljung was awarded with the SPPS Prize, Åsa Strand with the Physiologia Plantarum Prize and Torgny Näsholm received the SPPS Innovation Prize together with Barbara Halkier from the DynaMo Center at the University of Copenhagen (for more information about the prizes read also here).
In the afternoon of the second day, participants of the congress were visiting the Field Research Site “Rosinedal” that is located in a forest stand east of Vindeln. At this field site, researchers are studying in a long-term experiment the effect of nitrogen on the carbon balance of the forest. During the excursion, participants got an overview about the different studies that are made at “Rosinedal”. Via an QR-code, they could access additional information about the history of the field site and the research highlights. This technically advanced tour even motivated a local newspaper to write about it.
More information about Scandinavian Plant Physiology Society (SPPS): http://spps.se/
More information about “Rosinedalen’s” Field Site: https://www.slu.se/en/departments/field-based-forest-research/experimental-forests/vindeln-experimental-forests/rosinedal/
[2019-07-25] Today, on the anniversary of the decision of the Court of Justice of the European Union (CJEU) on plant breeding with the help of gen-editing, an open letter was sent to the Swedish European parliamentarians and the Swedish government. The letter is a call to action for an expedited change of the European legislation for genetically modified organisms (GMO). It has been signed by the leaders of 14 Swedish universities/research centres, royal science academies or research financiers as representatives of the independent Swedish research community.
“The decision of the European Court of Justice has such far-reaching consequences for research and for a more sustainable and environmentally friendly agriculture that the Swedish science community found it necessary to react strongly to try to achieve a change in legislation”, says Stefan Jansson, professor at Umeå University, who coordinated the letter.
Read the open letter (English and Swedish):
Open letter concerning GMO regulations (en)
Oppet brev om GMO lagstiftning (sv)
Attachment 1: Consequences of the EC-ruling according to Swedish companies and research groups (Swedish Board of Agriculture)
Attachment 2: Follow-up from PAFF-meeting on September 11, 2018 (Swedish Board of Agriculture)
The publication of the letter coincides with other activities at the international level that pursue the same purpose (see the links below):
Open Statement from European scientists coordinated by Dirk Inze from VIB in Ghent
European citizens' initiative: 'Grow scientific progress: crops matter!
For further information, please contact:
Umeå Plant Science Centre
Department of Plant Physiology
Phone: +46 70 677 23 31
The UPSC group leaders met in Skeppsvik for a lunch-to-lunch retreat on June 13th and 14th 2019. Sixteen PIs joined the retreat and discussed subjects related to UPSC’s strategy, investments for new infrastructure and upcoming recruitments of new group leaders to cover retirements.
Carolin Grabbe from the SLU Grants Office informed about funding opportunities for research, mobility and postdoc career development. Many ideas were brought forward at the retreat, especially regarding future recruitments. The PI-retreat was a welcome and appreciated opportunity for dialog and exchange of opinions and will be repeated on a yearly basis.
Text: Judith Felten
Photo: Sonali Ranade
Scots pine is one of the most commercially used tree species in Sweden. To be able to breed lines with improved growth, survival and properties is of great interest for tree breeders and the forest industry. Unfortunately, the tree breeding cycle of Scots pine lasts between 20 to 30 years and that causes that the evaluation of trees in breeding trials requires several years. In her PhD project Ainhoa Calleja-Rodriguez successfully evaluated new statistical methodologies that can aid to reduce the breeding cycle in the future and to improve the accuracy of the genetic parameters on growth, adaptive traits and wood quality traits of Scots pine. She successfully defended her PhD on Wednesday, 29 may at SLU Umeå.
In her study Ainhoa Calleja Rodríguez evaluated different families of Scots pine in several locations all over Sweden. Geographical variation was important as the environment has big impact on the behavior of the trees and with a new statistical method, called factor analysis, she was able to evaluate more characters simultaneously. Another new method called genomic selection was applied for the first time on Scots pine. Ainhoa showed that it may be possible to evaluate trees already at the seedling stage but also gives more accurate estimations of genetic variation of growth and wood quality traits then traditional methods.
Ainhoa was a student of the UPSC industrial graduate research school of forest genetics, biotechnology and breeding. Therefore, she was doing her PhD project not just as student at the department of forest genetics and plant physiology at SLU but also partly at the Swedish forest research institute Skogforsk, which has one main working focus on tree breeding.
Why did you choose your project?
I felt in love with tree improvement through a previous job experience as research technician and also from my master thesis in Spain, so when a colleague in Spain sent me the announce of this position in Sweden, I just did not doubt a second to send my application.
Did the fact that this PhD program you were in was located both in industry and academia influence the decision of starting on it?
Yes, it did, specially the industry part was essential for me to decide about this position. The fact that 20% of my time could be expend as internship at the host company (Skogforsk in my case), and be in direct contact with the operational breeding program and with the tree breeders, it was what made me decide for this PhD position.
What was most fascinating during your PhD?
The most fascinating was the opportunity of being Industrial PhD Student at the Second Research School of Forest Genetics, Biotechnology and Breeding, because it gave us the opportunity to attend PhD courses with the top professors in quantitative genetics and breeding, as well as to have a “field trip” to visit the most advanced breeding programs in USA and Brazil. Also, performing my internship within Skogforsk was also fascinating, especially because at the end one of the projects became part of the thesis and was key to improve my knowledge of quantitative genetics, linear mixed models and ASReml (the most common software used in plant and animal breeding).
What was the most disappointing experience you had during your PhD?
It was really hard to get good quality marker data for Scots pine. First time we tried, it took more than a year and half to get some data and finally their quality was not enough to use them, so the part of genomic prediction of my thesis was delayed. Fortunately when we tried the second time it did not take that long and we finally could use them.
What are your plans for the future?
Last month I had an interview and got a new job at Skogforsk as researcher, so I am finally going to work with the scientists there in the operational breeding program
About the defence:
The public defence took place on Wednesday, 29th of May in P-O Bäckströms sal at SLU Umeå. The faculty opponent was Heidi Dungey, Senior scientist and Science Leader of Forest Genetics, Scion (New Zealand Forest Research Institution) and her supervisor was Harry Wu.
Title of the thesis: Quantitative Genetics and Genomic Selection of Scots pine
Link to the thesis: https://pub.epsilon.slu.se/16094/
For more information, please contact:
[2019-05-21] On Saturday, 18th of May, the 5th Fascination of Plants Day was celebrated in Umeå with a public event. Almost 300 visitors came to Kafé Fika at Väven and got involved in many different activities around plants and plant science.
What colours are hidden in the leaves of plants? Why are the interactions between plants and insects so important? What are microalgae and how can they be used? The visitors were invited to hands-on activities around those and other topics. They could isolate DNA from strawberries, prepare seed bombs and learn more about how to grow mushrooms.
The aim of the Fascination of Plants Day is to fascinated people for plants and to generate awareness for the importance of plant science. It was launched under the umbrella of the European Plant Science Organisation (EPSO) and was first organised in 2012 on a European level but is now internationally celebrated. This year more than 800 events across 51 countries were organised.
The event in Umeå was organised by scientists from the Umeå Plant Science Centre, the Department of Chemistry, the Department of Ecology and Environmental Sciences, both from Umeå University, the Department of Forest Ecology and Management, Department of Forest Biomaterials and Technology, the Department of Agricultural Research for Northern Sweden, all three from SLU, by Skogforsk, the Forestry Research Institute of Sweden, the Swedish Bonsai society (Bonsaisällskapet) and the Broparken gardening project.
Photos: Anna Shevtsova
[2019-05-21] Thi Hai Hong Nguyen analysed how genetic variation influences wood and oil quantity and quality in Norway spruce and Melaleuca, a multi-purpose tree distributed in Australia, Papua New Guinea and South-East Asia. In her Phd thesis, she recommends tree breeding strategies for the two species to optimize their industrial usage. Thi Hai Hong Nguyen successfully defended her PhD thesis on Friday last week, 17th of May 2019.
Do trees that grow faster have lower wood quality and contain less oil or oil of lower quality? Is it better to use only one clone of a species in forestry or can it be of advantage to plant families, that means related trees that do not contain the exact same genetic composition? The answers to those questions are of high interest for the forest industry. Thi Hai Hong Nguyen estimated in her PhD thesis the genetic parameters that influence wood and oil quality and quantity and looked into the effect of genetic variation of Melaleuca and Norway spruce. Based on her results, she gives advices for tree breeding strategies for the two species.
The public defence took place in P-O Bäckströms sal at SLU Umeå on Friday, 17th of May 2019. Faculty opponent was Prof. Steven E. McKeand from the Faculty of Forestry and Environmental Resources, NC State University, USA. The supervisor was Harry Xiaming Wu.
Title of the thesis: Genetics, breeding and deployment of Melaleuca and Norway spruce
Link to the doctoral thesis: https://pub.epsilon.slu.se/16097/
Kungliga Skytteanska Samfundet, a scientific academy based in Umeå, hands out every year prizes for outstanding research and cultural commitment. This year, Ioanna Antoniadi, researcher at the Umeå Plant Science Centre, will receive the prize that is assigned to the Faculty of Forest Sciences from SLU.
Ioanna Antoniadi focusses in her research on root development and the role of plant growth factors that are controlling the development. Kungl. Skytteanska Samfundet valued in their motivation for the prize, that Ioanna Antoniadi contributed to an improved understanding of mechanisms that regulate growth and development of plants, a fundamental knowledge with potential application within plant cultivation.
After finishing her PhD at the Imperial College in London, Ioanna Antoniadi moved to Umeå in 2015. She started in the group of Karin Ljung at the Umeå Plant Science Centre, first as a postdoc and now as a researcher. She has published as author or co-author six scientific publications within the last five years and became the expert at UPSC for Fluorescence Activated Cell Sorting (FACS), a very advanced technique that allows detections on the single cell level.
Ioanna Antoniadi independently developed and optimised new methods based on the FACS technique. She could demonstrate that the plant hormone cytokinin forms a gradient in the root tip of the model plant Arabidopsis thaliana, with the highest concentration in the top. These results were published in the prestigious journal Plant Cell and are now well cited. She also contributed to studies about how plants react on the hormone level to different type of stresses, e.g. salt stress and mechanical stress.
Kungl. Skytteanska Samfundet is awarding in total six prizes to young researchers, a cultural prize, the “Margareta och Eric Modigs” prize that is assigned to the Medical Faculty of Umeå University, a prize for a young artist from the Umeå Academy of Fine Arts, a prize for a young musician from the School of Music in Piteå and the “Samfundets stora pris”. All prizes will be officially handed over at the societies “Årshögtiden” on Friday, 24th of May at Sävargården in Umeå.
About Fluorescence Activated Cell Sorting (FACS):
Cell sorting is a method that allows purification of highly specific cell populations from a mix of cells. It can be for example used to isolate scarce cell types, that are labelled with a fluorescence marker, from a plant tissue. The plant tissue is initially enzymatically digested to remove the cell walls which leads to the formation of protoplasts (plant cells that are surrounded only by the plasma membrane). The protoplast mixture is then loaded into the FACS instrument that acts as an extremely “sharp knife” sorting the cells according to their size, internal complexity and fluorescence. The sorted and isolated cells can then be used for further analyses in downstream applications.
More information about Kungl. Skytteanska Samfundet:
More information about the prize winners 2019:
For more information about Ioanna Antoniadi’s research, please contact:
Umeå Plant Science Centre
Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences
Phone: +46 (0)90 786 8628