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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #362101

Research Project: Enhanced Alfalfa Germplasm and Genomic Resources for Yield, Quality, and Environmental Protection

Location: Plant Science Research

Title: Detection and fungicide sensitivity surveillance of wild rice (Zizania palustris) pathogens

item CASTELL-MILLER, CLAUDIA - University Of Minnesota
item Samac, Deborah - Debby

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/9/2019
Publication Date: 8/3/2019
Citation: Castell-Miller, C., Samac, D.A. 2019. Detection and fungicide sensitivity surveillance of wild rice (Zizania palustris) pathogens. American Phytopathological Society (Plant Health 2019). August 3-7, 2019, Cleveland, Ohio.

Interpretive Summary:

Technical Abstract: Fungal brown spot caused by Bipolaris oryzae, and spot blotch caused by B. sorokiniana, are commonly found in cultivated wild rice paddies. Strobilurin-based fungicides are effective in reducing these diseases in the upper plant canopy. After three years of fungicide applications Bipolaris spp. populations decreased to low levels in wild rice plants early in the season, although the populations increased later in the year. Phenotypic identification of diseases based on small lesions early in the season is difficult and often misleading. To aid in an accurate and rapid detection of Bipolaris spp. pathogens, we developed SYBR Green-based PCR assays with primers designed from ITS1 and the B-tubulin genes. The assays discriminate both Bipolaris spp., and other fungal species. To maintain control of foliar diseases during the wild rice growing season, azoxystrobin-based fungicides are needed. Even though fungicide resistance is unlikely to develop in B. oryzae due to an intron after the G143 codon of the cytochrome b gene, changes toward reduced sensitivity could still occur in codons 129 and 137. To monitor changes in fungicide sensitivity, we developed a PCR assay based on TaqMan technology to detect changes from phenylalanine to leucine in position 129, while nucleotide changes in positions G143 and G137 will be monitored with the SYBR Green-based assays. These assays will aid in understanding the epidemiology of wild rice pathogens and timely application of fungicides.