Abstract Detail

Functional Genetics/Genomics

Chorak, Gregory [1], Clevenger, Josh [2], Harkess, Alex [3], Thum, Ryan [1].

Identifying a QTL for fluridone resistance in Eurasian watermilfoil (Myriophyllum spicatum) using an F1 cross and low coverage whole genome sequencing.

The herbicide fluridone (WSSA group 12) has been an effective management tool for aquatic plants since 1986. Nearly 20 years after its registration, a case of resistance to fluridone was documented in the aquatic plant Hydrilla verticillata. Fluridone acts by inhibiting the phytoene desaturase (PDS) enzyme, an important step in the production of carotenoids. Target-site mutations in the PDS gene has repeatedly been found as the cause of resistance to PDS inhibiting herbicides. Therefore, when fluridone resistance in the invasive aquatic macrophyte, Eurasian watermilfoil (Myriophyllum spicatum) was documented, we hypothesized that mutations in PDS was the cause. In this study, we aimed to identify the alleles responsible for fluridone resistance in Eurasian watermilfoil by crossing resistant and susceptible genotypes of watermilfoil to build a family that segregates for fluridone resistance. Because we started with naturally occurring genotypes that are likely heterozygous at many loci (not inbred lines), and because we hypothesized that resistance may be due to large effect mutations in the PDS gene, we screened the F1 cross. Indeed, we found that the F1 cross was segregating for fluridone resistance. Eurasian watermilfoil is an allohexaploid, which makes mapping of genes difficult because of mismatching of sequencing reads between the sub genomes. To solve this, we low coverage sequenced the whole genomes of the individuals of the segregating family and used a proprietary genotyping method for complex genomes known as Khufu (Hudson Alpha Institute). As hypothesized, we did find a large effect quantitative trait locus (QTL) associated with fluridone resistance. However, this large effect QTL is not located in the PDS gene. Eurasian watermilfoil is heavily managed in the United States, and fluridone treatments are an effective management tool which needs to be preserved. The ability to detect and track fluridone resistance alleles in populations of managed watermilfoil would be an invaluable tool for resistance management and is the ultimate goal of this research.

1 - Montana State University, Plant Science , Montana State University RM 119 Plant Bioscience BLDG, Bozeman, MT, 59717, USA
2 - Hudson Alpha Institute , 601 Genome Way, Huntsville , AL, 35806, USA
3 - Auburn University, HudsonAlpha Institute For Biotechnology, Harkess Lab, HudsonAlpha Institute For Biotechnology, 601 Genome Way, Huntsville, AL, 35806, United States

Aquatic plants.

Presentation Type: Oral Paper
Number: FGG2003
Abstract ID:862
Candidate for Awards:Margaret Menzel Award

Copyright © 2000-2022, Botanical Society of America. All rights reserved