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Proposal 2
Identification and Functional Analysis of Small RNAs in Systemic Acquired Resistance in
Arabidopsis thaliana
Summary
This is an important topic to study because systemic acquired resistance (SAR) can lead
to faster and strong defense responses in systemic tissue, to a broader spectrum of pathogens.
The gaps in knowledge being addressed in this proposal are the unknown signal(s) that initiates
systemic acquired resistance (SAR) and molecular mechanism underlying SAR. There appears to
be a connection between sRNAs and pathogen resistance response because sRNAs have been
identified in playing a role in PAMP-triggered immunity and effector-triggered immunity. There
are also four major families of proteins involved in sRNA biogenesis and function in
Arabidopsis. Based on these connections established by the authors, they hypothesize that
sRNAs and sRNA pathway components function in SAR.
The first objective is to perform a genetic evaluation of the function of the four major
families involved in sRNA biogenesis and function (DCL1-4, RDR 1-6, AGO1-10, polIV, and
polV). Their plan is to use loss-of-function mutants in a bacterial infection assay and gene
expression study.
The second objective is to perform high-throughput sequencing of the sRNAs involved in
SAR. Their plan is to produce HA-tagged AGO overexpression plants and perform CoImmunoprecipitation followed by sRNA sequencing.
The third objective is to identify and characterize the sRNAs and their target genes. Their
plan is to collaborate with Xiu-Jie Wang’s lab from the State Key Laboratory of Plant Genomics,
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences for the
identification of the sRNAs and their target genes. Then to determine the functions of the sRNA
and target genes in SAR they plan to use a combination of qt-PCR, western blotting, and loss-offunction mutants.
Strengths/Weaknesses
 Strengths
o The introduction and literature supporting the proposal was well researched,
strengthening their hypothesis and basis of the proposal.
o Experiments are detailed showing excellent preparation and the ability to begin
the experiments in a timely manner.
o They clearly outline expected results and identify problems they might come
across demonstrating familiarity with the techniques and procedures.

Weaknesses
o The future directions section does not seem to be well related to the proposal; the
projects in the future directions do not seem to stem from the results of this
proposal.
Broader Impacts
Identifying new components in SAR and having a better understanding of the mechanism
will be integrated into crop plants as an additional layer of protection against pathogens as well
as generating new cultivars of disease-resistant crop plants.