Project Number: 5358-12220-004-03
Project Type: Grant

Start Date: Sep 28, 2010
End Date: Sep 30, 2013

Objective:
1) Validate a quantitative PCR (qPCR)-based assay for P. rubi evaluations from raspberry roots and soil. 2) Continue evaluations of solarization and Brassicacaceous seed meal amendments as preplant treatments for raspberry. 3) Establish trials to determine whether bed fumigation and alleyway management methods sufficiently delay pathogen entry into planting beds to permit successful plant establishment.

Approach:
First, we will validate a quantitative molecular assay to improve our ability to evaluate treatment effects on P. rubi. The bioassay we currently use is very sensitive to small amounts of P. rubi but not distinguish moderately effective treatments from non-treated controls. A truly quantitative assay will give us a more realistic assessment of the efficacy of treatments. A quantitative real-time PCR (qPCR) assay for P. rubi is already in development in our lab. We verified that we can amplify and detect the correct region of P. rubi DNA, and propose to validate the test across multiple P. rubi isolates, and validate that it is accurate using DNA recovered from soil or raspberry roots. In preliminary experiments, we found that soils amended with Brassica juncea or Sinapis alba seed meal suppressed P. penetrans; Agrobacterium tumefasciens was also suppressed in B. juncea-amended soils. Solarization is another non-chemical pretreatment option, which has been shown to prevent root rot for 2-3 years in western Washington fields.