Review of “Regulation of R-gene Mediated Resistance via Light Dependent Pathways
in Plants”
2010-5
Secondary Reviewer: Trevor Nolan
Score: Very Good
This proposal sets out to examine the relationship between light and defense
response. The overarching hypothesis is that light perception influences defense
response and might affect the outcomes of plant pathogen interactions. The
introduction is well crafted and points out the precedence for such interactions
between light signaling and defense. To study these processes, the authors have
proposed a set of experiments to examine mRNA and protein levels of R genes in a
time course that encompasses both light and dark conditions and to correlate these
changes with levels of pathogen susceptibility. To take this a step further, the
researchers will subject Arabidopsis to different photoperiods and look at R gene
mRNA and protein level as well as downstream responses such as hypersensitive
response. Lastly, the authors will test the effects of photoreceptors and the circadian
clock by using mutants in each of these pathways and looking at similar readouts.
Strengths of this proposal include the level of detail and cohesiveness of the
experiments to be performed. The study is also somewhat broad in that it proposes
to investigate 14 different R genes. The use of mutants as well as altered
environmental conditions also strengthens this proposal. Despite these merits,
several shortcomings prevent it from earning the highest score.
One of the primary experiments proposed for this study involves looking at
protein levels for R genes, but the availability of reagents to do so is not made clear.
Are high quality commercial antibodies available for all of the R genes to be studied
or do the authors plan to produce these themselves? Additionally, it would have
been useful for the authors to include preliminary data regarding the regulation of
the R gene mRNA levels during day night cycles; it is very likely that many of these
data could be obtained from public databases. Lastly, most of the experiments
proposed will only allow a correlation to be made between R gene
expression/protein level and pathogen susceptibility. To this end, more experiments
should be proposed such as overexpressing light-responsive R genes under a
constitutive promoter to remove transcriptional regulation and determining the
effect on pathogen interactions.
In the area of broader impacts the authors make a reasonably well-supported
cases for the study of R genes to improve crop engineering and yield, but they could
do a better job explaining why our current knowledge is limiting for this application
and how the proposed study would be of benefit. Altogether, this proposal earns a
mark of very good due to the well-constructed design of the studies and interesting
conclusions that might be drawn.