This project will determine the function of a network of genes involved in disease resistance. The genes studied will be chosen from among those found to be expressed at increased levels after pathogen infection. As several thousand genes satisfy this condition, genes will be prioritized based on other characteristics, such as rapid expression changes or annotation suggesting functions in signaling, secondary metabolism, or unknown function. There are four Specific Aims:

1. Obtain global expression profiles for Arabidopsis responses to P. syringae infection

2. Identify genes that contribute to resistance to P. syringae.

3. Identify genes comprising the defense signaling circuitry controlling activation of defense responses.

4. Model the defense signaling circuitry using gene expression profiles of regulatory mutants.

1. The pathogen-induced genes that we have targeted for reverse genetics analysis are listed under the link "Genes of Interest". The table labeled "For eds testing-proposal" is the list of genes from our original proposal for which we planned to test mutants for enhanced disease susceptibility phenotypes. The table labeled "For R-gene signaling-proposal" is the list of genes from our original proposal for which we planned to test mutants for defects in R-gene mediated signaling. These versions of the lists were created based on data from the 8,000 gene Arabidopsis Affymetrix array. As our project proceeded, we found that T-DNA insertion lines could not be obtained for some of the genes on these lists. Consequently, we will not be able to test them in our project. We have also added some target genes based on new data from the ATH1 Affymetrix array. To see which genes we are actively studying, use the lists of genes for which we have identified homozygous T-DNA insertion lines, described in the next section.

2. We have identified 195 homozygous T-DNA insertion lines that will be subjected to eds testing. They are shown in the table "T-DNA lines for eds testing". We will continue to add lines to this list, and update it periodically.

We have identified 95 homozygous T-DNA lines with mutations in genes that are induced early during gene-for-gene resistance. These lines will be subjected to expression profiling using a custom mini-array to test for defects in signaling during R-gene mediated resistance. They are shown in the table "T-DNA lines for R-gene testing".

Both of these lists can also be found under the link “Genes of interest”.

3. We have designed a mini-array representing pathogen-responsive genes with many different patterns of gene expression. This array is undergoing quality-control testing presently. The list of genes represented on the mini-array, and probes used are shown in the table "Mini-array design".