Keehoon Sohn & Jonathan
D. G. Jones talk with ScienceWatch.com and answer
a few questions about this month's Fast Breaking Paper in
the field of Plant & Animal Science
Article Title: The downy mildew effector proteins
ATR1 and ATR13 promote disease susceptibility in
Arabidopsis thaliana
Authors: Sohn,
KH;Lei, R;Nemri, A;Jones, JDG
Journal: PLANT CELL
Volume: 19
Issue: 12
Page: 4077-4090
Year: DEC 2007
* John Innes Ctr, Sainsbury Lab, Norwich NR4 7UH, Norfolk,
England.
* John Innes Ctr, Sainsbury Lab, Norwich NR4 7UH, Norfolk,
England.
Why do you think your paper is highly
cited?
We report a novel method of using bacterial type III secretion (T3S) to
deliver oomycete effectors into plant cells, as well as the first molecular
evidence showing oomycete effector-mediated suppression of plant immunity.
We coordinated publication with the Brian J. Staskawicz lab at the
University of California, Berkeley, which was taking a similar approach (MC
Rentel et. al., PNAS, 2008).
Does it describe a new discovery, methodology, or
synthesis of knowledge?
The most significant and new observation in the paper is that oomycete
effectors can be delivered by bacterial T3S and the T3S-delivered oomycete
effectors can activate or suppress plant innate immunity to bacterial
pathogen. This creates a method that might be used to assay any effector
from a eukaryotic pathogen.
Would you summarize the significance of your paper in
layman's terms?
Coauthor
Jonathan D. G. Jones
In nature, plants are exposed to various potentially pathogenic microbes.
However, most plants are resistant to most pathogens and therefore survive.
Microbes evolved to overcome plant innate immunity by delivering highly
evolved drugs (effectors) into plant cells. Therefore, identification of
effector functions is one of the keys to understanding pathogen virulence
and host defense. Our paper describes a novel method to study effector
functions and we believe the method will accelerate research into plant
pathogens in the future.
How did you become involved in this research, and were
there any problems along the way?
It became clear that genome sequences of the most important plant disease
organisms would become available. However, the challenge was figuring out
how to assay candidate genes for involvement in plant/pathogen interaction.
Delivery via T3S from P. syringae provides a better assay than we
had dared hope. The main difficulty, as always in this field, is generating
reproducible pathogen growth data, because it is difficult even in growth
chambers to ensure reproducibility of host plant material.
Where do you see your research leading in the
future?
This idea of using bacterial T3S system to deliver oomycete effectors
provides a new opportunity to investigate functions of effectors from
various pathogens, particularly the pathogens that are difficult to
genetically engineer. We plan to investigate functions of effectors from
economically important oomycete and fungal pathogens using this method,
particularly Albugo candida (white rust) of brassicas and
Arabidopsis. We also will test whether non-host resistance (e.g.,
resistance in Arabidopsis to brassica strains of a pathogen)
results from Arabidopsis recognition of some of the effectors from
the brassica strain, and if so, whether those Arabidopsis
recognition genes can be identified and moved into brassica.
Do you foresee any social or political implications for
your research?
Food supplies are tight. The application of agrochemicals is unpopular. We
must use the best possible genetic strategies to improve crop resistance to
disease. This may involve taking resistance genes from one plant (e.g.,
Arabidopsis) and putting them into another (e.g., brassicas). This
may be controversial, but the battle must be fought.
Keehoon Sohn, Ph.D.
Postdoctoral scientist
Jonathan Jones Group
Sainsbury Laboratory
John Innes Centre
Norwich, UK Web