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Key to aphid invasion success found

16 February 2011

Aphids are some of the most destructive insect pests of crop plants, not only through the damage they cause from feeding but also through transmitting a variety of economically important diseases. Part of what makes them so effective is the way they can control some of the activities of plants, suppressing their defences and so helping the aphids feed. New research from the John Innes Centre, an institute of Biotechnology and Biological Sciences Research Council, has identified components of the aphid's saliva that manipulate the plants defences.

Many pathogenic organisms that cause plant diseases secrete proteins, called effectors, which overcome the host plant's defence mechanisms and so ensure the success of the pathogen. Dr Jorunn Bos, working with Dr Saskia Hogenhout at the John Innes Centre, used knowledge gained about the effectors produced by plant pathogens to identify possible effector proteins in the saliva of aphids.

Plant pathogen effector proteins share a number of common features, in particular a signal peptide that directs the cell to excrete the effector proteins. The researchers screened thousands of publicly available aphid saliva gland proteins, identifying 48 potential candidates for effector proteins. Using an assay system developed for this study they were able to study the effects of these candidate effectors on plant defence responses as well as aphid fecundity. Three of the candidates were found to trigger plant defences and/or affect the performance of aphids, suggesting that they may be used by the aphids as effectors.

"This is the first time that specific effector proteins with activities in plants have been identified in aphid saliva, and this pioneering work is giving us a better chance of understanding exactly how aphids manipulate plants to their own benefit" said Dr Saskia Hogenhout. "This knowledge will be crucial if we are to develop novel, sustainable ways of controlling aphids and some of the devastating diseases they transmit."

Prior to this, Jorunn worked with Professor Sophien Kamoun of The Sainsbury Laboratory on effector proteins in the pathogen that causes late blight in potatoes, Phytopthora infestans. In particular, they focused on the first effector gene identified in P. infestans (Avr3a), which Jorunn characterised for her PhD project under the supervision of Sophien Kamoun at the Ohio Agricultural Research and Development Centre (OARDC) at the Ohio State University.

In collaboration with Paul Birch at the Scottish Crop Research Institute and the University of Glasgow, the precise target of Avr3a was uncovered. It was found that Avr3a blocks the plant from deploying part of its defence mechanism, so aiding the pathogen's entry into the plant. In fact, this mechanism is vital to the success of the pathogen invasion, as when the researchers silenced Avr3a, P. infestans lost its invasive abilities. Combining fundamental understanding of the pathogen effector proteins with the increasing amount of genomic data from aphid species has been key to identification of the first aphid saliva effector proteins.

The precise molecular targets and pathways that are affected by these newly identified aphid saliva effector proteins are now being studied both at the John Innes Centre and at the Scottish Crop Research Institute (SCRI), where Jorunn Bos has recently started an Independent Research Fellowship funded by the Royal Society of Edinburgh and the Scottish Government.

ENDS

Notes to editors

Reference: A Functional Genomics Approach Identifies Candidate Effectors from the Aphid Species Myzus persicae (Green Peach Aphid) Bos et al, PLoS Genet 6(11): e1001216. www.plosgenetics.org/../doi:10.1371/journal.pgen.1001216.

Funding: Marie Curie International Reintegration Grant, The Gatsby Charitable Foundation, the Biotechnology and Biological Sciences Research Council (BBSRC), the University of Turin, Italy.

Collaboration: Plant Physiology Unit, Department of Plant Biology and Centre of Excellence CEBIOVEM, University of Turin, Turin, Italy.

Reference: Phytophthora infestans effector AVR3a is essential for virulence and manipulates plant immunity by stabilizing host E3 ligase CMPG1, Bos et al. PNAS May 25, 2010 vol. 107 no. 21 9909-9914 www.pnas.org/content/107/21/9909.

Funding: This work was supported by the Gatsby Charitable Foundation at The Sainsbury Laboratory and by the Rural and Environment Research and Analysis Directorate and Biotechnology and Biological Sciences Research Council funding at the Universities of Dundee and Glasgow and at the Scottish Crop Research Institute.

Collaboration: Plant Pathology and Genetics Programmes, Scottish Crop Research Institute, Institute of Biomedical and Life Sciences, University of Glasgow, Division of Plant Sciences, College of Life Sciences, University of Dundee at the Scottish Crop Research Institute, Department of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China; and Uppsala BioCenter, Department of Plant Biology and Forest Genetics, University of Agricultural Sciences, Uppsala, Sweden.

About BBSRC

BBSRC is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £470M in a wide range of research that makes a significant contribution to the quality of life in the UK and beyond and supports a number of important industrial stakeholders, including the agriculture, food, chemical, healthcare and pharmaceutical sectors.

BBSRC provides institute strategic research grants to the following:

  • The Babraham Institute
  • Institute for Animal Health
  • Institute of Biological, Environmental and Rural Sciences (Aberystwyth University)
  • Institute of Food Research
  • John Innes Centre
  • The Genome Analysis Centre
  • The Roslin Institute (University of Edinburgh)
  • Rothamsted Research

The Institutes conduct long-term, mission-oriented research using specialist facilities. They have strong interactions with industry, Government departments and other end-users of their research.

External contact

5 November 2009

Scientists from the John Innes Centre in Norwich, UK and the University of Freiburg in Germany have uncovered a gene in plants that is responsible for controlling the size of seeds, which could lead to ways of improving crops to help ensure food security in the future.

Increasing seed or grain size has been key in the domestication of the crops used in modern agriculture, and with a growing world population, further increasing the yield of crops is one goal of agricultural research. Michael Lenhard, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), has identified a gene in the model plant Arabidopsis that determines overall seed size, and is now investigating how this could be used to for the improvement of crops.

Publishing in the Proceedings of the National Academy of Sciences, the team from the John Innes Centre, an institute of the BBSRC, demonstrated that the gene acts locally at the base of the growing seed. It produces an as yet unidentified mobile growth signal that determines final seed size. If the gene is turned off, smaller seeds are produced, but crucially if the gene is turned on at a higher level than normal, seeds a third larger in size and weight are produced. This is the first time such a reciprocal effect on seed size has been observed, and points to the fundamental importance of this gene in plant development.

More work is now needed before this research can be applied to crop plants. One effect of increasing the seed size in the experimental plants was to decrease the total number of seeds produced, so there was no overall increase in yield. The scientists did notice an increase in the relative oil content of the larger seeds, so the effects of altering this gene in oil seed rape is currently being investigated.

Unravelling this gene’s role in determining the final seed size will also be important for other strategies for increasing yield, an example of how fundamental plant science can inform and drive efforts to ensure food security

Professor Mike Bevan, Acting Director of the John Innes Centre, said “This work shows how JIC's focus on understanding the mechanisms controlling plant growth can have immediate useful application for crop improvement.”

ENDS

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Nikolai Adamski and Michael Lenhard examining Arabidopsis (323KB)


 

Notes to editors

Reference: Local maternal control of seed size by KLUH/CYP78A5-dependent growth
Signalling, PNAS.

Funding: BBSRC David Phillips Fellowship.

About the John Innes Centre

The John Innes Centre, www.jic.ac.uk, is an independent, world-leading research centre in plant and microbial sciences with over 800 staff. JIC is based on Norwich Research Park and carries out high quality fundamental, strategic and applied research to understand how plants and microbes work at the molecular, cellular and genetic levels. The JIC also trains scientists and students, collaborates with many other research laboratories and communicates its science to end-users and the general public. The JIC is grant-aided by the Biotechnology and Biological Sciences Research Council.

About BBSRC

The Biotechnology and Biological Sciences Research Council (BBSRC) is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £450M in a wide range of research that makes a significant contribution to the quality of life for UK citizens and supports a number of important industrial stakeholders including the agriculture, food, chemical, healthcare and pharmaceutical sectors. BBSRC carries out its mission by funding internationally competitive research, providing training in the biosciences, fostering opportunities for knowledge transfer and innovation and promoting interaction with the public and other stakeholders on issues of scientific interest in universities, centres and institutes.

The Babraham Institute, Institute for Animal Health, Institute of Food Research, John Innes Centre and Rothamsted Research are Institutes of BBSRC. The Institutes conduct long-term, mission-oriented research using specialist facilities. They have strong interactions with industry, Government departments and other end-users of their research.

External contact

Andrew Chapple, John Innes Centre

tel: 01603 251490

Zoe Dunford, John Innes Centre

tel: 01603 255111

11 October 2005

The following stories appear in the October 2005 edition of Business, the quarterly magazine of research highlights from the Biotechnology and Biological Sciences Research Council (BBSRC).


Controlling 'superpests'
Scientists have developed a new technique that helps make pesticides more effective by removing insects’ ability to exhibit resistance. Their research will extend the effective life of current pesticides, reduce the amount that needs to be sprayed and remove the need for farmers to move to stronger and more harmful chemicals. The new technique relies on applying a chemical to block the insect’s processes that can degrade a pesticide. With the pests newly rendered helpless farmers can apply pesticide to kill them.
(Page 13)

Contact:
Dr Graham Moores, Rothamsted Research, Tel: 01582 763133 ext 2483, e-mail:graham.moores@rothamsted.ac.uk


Fruit fly studies open new avenue in cancer research
Researchers have discovered a family of amino acid transporters that are powerful growth promoters in fruit flies. When the transporters were overexpressed in a fly, its cells became hypersensitive to insulin-like molecules in the body that have a long-term role in promoting cell growth in development and cancer, and the cells grew excessively. If the equivalent genes in humans have the same effect then this discovery could lead to new drugs or even dietary advice that could block their activity and slow down the growth of tumours.
(Page 20)

Contact:
Dr Deborah Goberdhan, University of Oxford, Tel: 01865 282662, e-mail: deborah.goberdhan@anat.ox.ac.uk


Gene delivery vehicle for skeletal regeneration
UK scientists are working on new methods to regenerate cartilage and bone by delivering genes to stem cells within the body to instruct them to turn into bone cells. The new research will use tiny nanoscopic systems that cross the surface of a stem cell and then deliver the genes into that prompt the cell to turn into a bone cell. This method of gene delivery could provide significant healthcare benefits as trauma, degenerative disease and bone loss with old age all lead to patients needing orthopaedic procedures that require new bone.
(Page 26)

Contact:
Professor Richard Oreffo, University of Southampton, Tel: 023 8079 8502, e-mail: roco@soton.ac.uk


'Ending up' with antibody production
Scientists are pioneering a new technique to produce large numbers of antibodies quickly and reliably and this is being used to help the study of dangerous bacteria. The new technique harnesses the unique properties of the C-terminus of a protein to produce a large number of antibodies that will only bind to a specific protein. The antibodies can then be used to identify, count and track the proteins. Proteins are central to many areas of bioscience research as they are often the targets for vaccines, the raw materials for bioprocessing or are employed as environmental biomarkers. Production of panels of antibodies that previously took years may now be possible in just weeks.
(Page 14)

Contact:
Dr Rob Edwards, Imperial College Hammersmith Hospital, Tel: 020 8383 2055, e-mail:r.edwards@imperial.ac.uk


Building proteins on demand
A multidisciplinary team of researchers is developing new tools to direct the evolution of proteins, a move that will help the search for new anti-HIV drugs. The scientists have developed an efficient methodology for generating every possible mutation of a single protein and then assembling this into a library to identify which variations are resistant to drugs and which are not. This information can then be used to develop and validate new drugs.
(Page 9)

Contact:
Dr Cameron Neylon, University of Southampton, e-mail: d.c.neylon@soton.ac.uk


Bringing physical forces to bear
World-leading laser facilities at the Rutherford Appleton Laboratory in Oxfordshire will be harnessed for biological studies thanks to joint funding from two Research Councils. A new laser system will study the bonds between atoms by looking at the unique frequency of their vibration. The new system will be able to take measurements of these ‘vibrational fingerprints’ at a scale so small that they will by able to study how cells repair damaged DNA, how proteins fold and develop new ways of detecting cancerous and pre-cancerous cells.
(Page 6)

Contact:
Professor Tony Parker, CCLRC Rutherford Appleton Laboratory, Tel: 01235 445109, e-mail: a.w.parker@cclrc.ac.uk


‘Model gut’ moves to commercialisation
Researchers at the Institute of Food Research in Norwich are moving closer to turning ten years of research on the workings of the human gut into a computer controlled model that will enable scientists to predict the digestive processes of human gut using real food and medicines. The result will be a revolutionary research tool that will enable researchers to examine the physical, chemical and biochemical functions of the gut as a whole.
(Page 3)

Contact:
Zoe Dunford, Institute of Food Research, Tel: 01603 255111, e-mail: zoe.dunford@nbi.ac.uk

ENDS

About BBSRC

The Biotechnology and Biological Sciences Research Council (BBSRC) is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £380 million in a wide range of research that makes a significant contribution to the quality of life for UK citizens and supports a number of important industrial stakeholders including the agriculture, food, chemical, healthcare and pharmaceutical sectors. http://www.bbsrc.ac.uk