ARS | Publication request: Genomic analysis of soybean defense response to Sclerotinia sclerotiorum

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 11, 2008
Publication Date: July 26, 2008
Citation: Calla, B., Simmonds, D., Clough, S.J. 2008. Genomic analysis of soybean defense response to Sclerotinia sclerotiorum [abstract]. American Phytopathological Society Annual Meeting. 98:S30.

Technical Abstract: We have conducted microarray studies on changes in soybean transcript levels in response to Sclerotinia sclerotiorum infection. These stem inoculations enabled us to identify genes that are differentially expressed in soybean plants in partially resistant versus susceptible varieties. We are expanding these studies to include effects of oxalic acid (OA), a major virulence factor of S. sclerotiorum. The OA studies involve leaf inoculation or OA infiltration in an oxalate-oxidase resistant transgenic and its susceptible parent. To assist with the identification of key defense genes, we assigned genes into functional categories based on the annotation of their closest sequence match in public databases and we clustered the genes across multiple experiments. Candidate defense genes are being further characterized by quantitative real-time RT-PCR to verify that the correct gene was identified in the microarray experiments. Promising genes will be functionally characterized by obtaining knockouts of these genes in soybean and/or Arabidopsis thaliana. To obtain knockouts in soybean we will use a viral induced gene silencing system and/or generate stable transgenics utilizing RNAi constructs. Additionally, overexpression of candidate defense genes will be studied in Arabidopsis and soybean. Promising candidate defense genes will be mapped to see if they map to known QTLs related to defense to S. sclerotiorum.