Beet crop wild relative germplasm mining uncovers new sources of disease resistance

Authors: Dorn, Kevin

Submitted to: International Plant and Animal Genome IX Conference
Publication Type: Abstract Only
Publication Acceptance Date: 9/21/2023
Publication Date: 9/21/2023
Citation: Dorn, K.M. 2023. Beet crop wild relative germplasm mining uncovers new sources of disease resistance. International Plant and Animal Genome Conference Sugar Crops Workshop. Meeting Abstract.

Interpretive Summary:

Technical Abstract: Sugar beet (Beta vulgaris) provides over 20% of refined sugar production globally, and over half in the United States. Substantial gains have been achieved in yield potential and important agronomic traits with the adoption of genome-assisted breeding, however, losses to a growing number of pests and pathogens highlights the need for a strategic reinvestment for improving host plant resistance. In sugar beet, and other beet crop types, the use of crop wild relatives including Beta vulgaris spp. maritima (sea beet) have enabled the discovery of novel disease resistance traits not present in the primary gene pool. Rhizoctonia solani, which causes Rhizoctonia Root and Crown Rot (RRCR) in sugar beet, is a ubiquitous soil-borne fungal pathogen regularly causes upwards of $50 million in actualized losses in the US annually. We have successfully mapped the genomic location of a novel quantitative trait loci (QTL) for RRCR resistance derived from a USDA-ARS Fort Collins pre-breeding germplasm called FC709-2 using bi-parental mapping populations. Our ongoing search for novel forms of RRCR resistance has been extended into sea beet, utilizing greenhouse-based RRCR resistance screening of a sea beet mini-core collection. To enable the use of a modified bulk segregant analysis and sequencing approach to map resistance loci from this collection, we have developed the first fully-phased chromosome scale assembly of a RRCR resistant sea beet plant. Work is ongoing to differentiate the resistance identified from the sugar beet germplasm FC709-2 from the resistance identified in sea beet, including de novo annotation of the sea beet genome using PacBio IsoSeq reads, molecular marker development, and candidate gene identification. Collectively, these genomic resources and new RRCR resistance traits enable the stacking of robust resistance to a globally important disease facing beet production, plus providing the tools necessary to better study the molecular interaction between Rhizoctonia and beet.