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Department of Plant Sciences

 
The overarching theme of the Plant-Parasite/Pathogen Interactions Group is to combine genomics and molecular biology to understand fundamental questions in host:parasite biology. The group primarily focuses on plant-parasitic nematodes because they are a threat to food security in developed and developing countries and because  underlying this threat is a wealth of fascinating biology that until very recently has been largely unexplorable. Projects include:
 

The 'readers' and the 'regulators'

What distinguishes plant-parasitic nematodes from many other plant pathogens is the presence of specialised gland cells that produce effectors. Discrete subsets of the effector repertoire are delivered into the plant in waves, over the course of several weeks. This project aims to understand this spatio-temporally controlled 'parasitism programme': how the parasitism process is regulated over time, in the nematode and in the plant. We anticipate a small number of regulators that control the concerted action of a large number of effectors – if we can disrupt the few regulators, we can simultaneously disrupt hundreds of effectors.
 
We recently discovered the 'DOG box': a promoter motif that unifies hundreds of otherwise sequence-unrelated effectors that are expressed in the same gland cell. The DOG box is our first insight into the regulation of the parasitic process. The fact that a single DNA motif unifies these effectors, implies the existence of a 'reader' and/or 'regulator': likely a protein, or protein complex, which coordinates tissue specific-expression through sequence-specific binding to the DOG box. This project will characterise these 'readers' and 'regulators' of parasitism.
 

The plant development- and immunity-altering 'toolbox'

Plant-parasitic nematodes have the remarkable abilities to suppress plant-immunity, and to cause existing plant cells to re-differentiate into a novel tissue. The extent of host-plant manipulation is rapid and profound: the cell cycle is arrested at G2, and the number and/or size of almost every sub-cellular organelle is drastically increased (nuclei, endoplasmic reticulum, mitochondria and plastids). In a recent effort we have identified a comprehensive list of one of the 'toolboxes' that cyst nematodes use to manipulate their host. It is thus likely that within this effector repertoire lie genes that are able to dictate the outcomes of plant organelle development. This project aim to understand the targets and molecular detail of such effectors.
 

Plant-parasitic nematode genomes and transcriptomes

Over the last few years we have sequenced genomes and or transcriptomes for nematode species that straddle almost every major phylogenetic bifurcation that gave rise the sedentary endoparasites: the most economically important species. Most notably this includes the completion of the G. rostochiensis genome consortium. We have ongoing genome projects for a number of cyst nematode species, most recently including the Heterodera schachtii genome consortium, and are always looking for interesting species to analyse. A current focus of our genomics research is to understand the genetic mechanism/s that underlie the juxtaposition of genomic variability and stability in effectors.
 

The contribution of horizontal gene transfer to plant-parasitism by nematodes

We have known for some time that the genomes of plant-parasitic nematodes have acquired genes from non-metazoans by horizontal transfer. Many of these genes encode cell-wall degrading/modifying enzymes that appear to be involved in host invasion. Genome-wide analyses of horizontal gene transfer have identified a number of other classes of genes that may be involved in other parts of the infection process. This project will investigate how the biochemistry of proteins encoded by horizontally acquired genes has changed following transfer, and how these functions contribute to plant-parasitism.
 

Transformation of plant-parasitic nematodes

With the help of BBSRC funding, we recently established the transformation of plant-parasitic nematodes consortium with the goal of coordinating efforts from groups around the world to deliver credible strategies for subsequent development; ultimately leading to a robust transformation method. Recent support from the Isaac Newton Trust, Wellcome Trust and the University of Cambridge is allowing us to progress in this area. We are always interested in discussing and testing ideas to make transformation for plant-parasitic nematodes a reality.
 
a lot of light blue cockscrew swirls clumped together turning slowly from let to right

Joining the group

Contact Head of Group Dr Sebastian Eves-van den Akker if you're interested in joining the group or finding out more about the group's research.

transgenic potato plants
Transgenic potato plants which target nematode genes

 

a thaliana root
Plant parasitic nematode causes tissue re-differentiation in A. thaliana root (stained orange)

 

protein crystals
Protein crystals and

 

crystal structure
first crystal structure of a nematode effector