Review for primary proposal, titled “ NO TILTLE GIVEN”
Michelle Guo
Summary: Xanthomonas oryzae pv. Oryzicola (Xoo) triggers hypersensitive responses (HR) in
barley and maize (nonhost interaction-resistance), but colonizes rice to cause bacterial blight
disease (host interaction-susceptible). The PI proposes to identify effectors in Xoo and interacting
proteins in barley, which may be transformed to rice and generate Xoo-resistant rice. AvrRxo1, a
T3SS (type III secretion system) effector in Xoo, triggers HR in maize, but not in rice. Rxo1
identified in maize is a R protein recognizing AvrRxo1. Nonhost resistance was observed in
Rxo1-transgenic rice.
Hypothesis: Effector (s) in Xoo can elicit nonhost resistance in Maize and Barley, and the Xoo
effectors responsible for HR in Barley can be identified.
The final goal of the proposal is that identification of effectors in Xoo triggering HR in barley
will lead to the identification of effector-interacting proteins in barley, which can potentially be
used to generate Xoo-resistant rice.
Approach 1. Identification of effectors in Xoo: The PI proposed to use bioinformatics to identify
effectors in Xoo, to introduce each effector to barley and to identify HR-triggering effector
carried in Xanthomonas campestris pv. Raphani strain 756C. They will then knockout potential
effector(s) identified in Xoo to test HR in barley.
Approach 2. Transcriptome analysis: The PI proposed to perform RNA-seq in response to host
and nonhost Xanthomonas to identify nonhost pathogen-responsive genes in barley, to compare
the genes responsive to SA (salicylic acid), JA (jasmonic acid) and ET (ethylene); VIGS (virusinduced gene silencing) and VOX (virus-induced overexpression) are used for confirmation of
gene function
Strength:
1. Rice is an important crop plant, fighting the bacterial blight disease in rice is
important;
2. Understanding host and nonhost interaction is important in plants, especially in crop
plants.
Weakness:
1. No title is provided;
2. The proposed approaches cannot fully address the final goal; another objective
should be provided to identify the corresponding R proteins in barley, which can signify the
potential in generating Xoo-resistant rice;
3. The PI did not provide enough background information on SA, JA and ET’s
involvement in disease and defense while proposing to compare the transcriptomes;
4. The proposal is not ambitious enough for a $500,000 grant, and only two half-time
students would work on this proposal;
5. Very limited references (10) are cited, reflected by the unthorough introduction, which
makes it difficult to justify the significance of the project, and reference are needed in many
places;
6. There are too many grammar and spelling errors: “…will chose to pursue…”, “…it’s
presence…”, “…instead of induce…”.
The proposed study is potentially important. However, the proposal is not ready for a
major grant. The PI needs to have a more thorough analysis of literature in the related
field, develop more clear hypotheses and propose significant experiments to test the
hypotheses. I give this proposal a rating of “fair”.