Population Genetics of Pueraria montana var. lobata

Kudzu, Pueraria montana var. lobata, sometimes referred to as “the vine that ate the south”, is an invasive species native to southeast Asia. The vine covers over 3 million ha across 30 states and is continuing to expand due to its rapid growth, 20-30 m per year, and vegetative propagation. In recent years its management costs have annually totaled in the millions. Historically, it has been introduced for livestock forage, nitrogen soil enrichment, and erosion control but it was first brought into the United States (US) from Japan as an ornamental display in 1876, during the Centennial Exposition in Philadelphia, PA. Tens, if not hundreds, of millions of plantings proceeded from the late 1800s to the mid-1900s. First, I discuss the creation of molecular markers for the study of kudzu, its varietal counterparts (P. montana var. montana and P. montana var. thomsonii), and Neustanthus phaseoloides (tropical kudzu). I de novo assemble and characterize three transcriptomes, two of kudzu and one of tropical kudzu, to identify two sets of population genetic markers, eSSRs and SNPs, and make both intra- and inter-specific transcriptomic comparisons. I then validate the eSSRs across an exploratory data set of 75 P. montana from native and introduced populations. Second, I investigate the population structure and introduction history of US kudzu using Bayesian and coalescent approaches. Enhancing the resolution of my eSSRs, I add previously identified gSSRs to better characterize the demographics of kudzu. I begin by comparing the two microsatellite marker sets and find differences in their informativeness. Next, I further examine my exploratory data set using STRUCTURE, MIGRATE-N, and DIYABC, from which I identify genetic structuring within the 75 P. montana and I find a pattern of introduction leading from China to both Japan and the US. Finally, I use a reduced representation method for genomic next-generation sequencing on 664 P. montana to provide enough resolution to identify the native population origins of introduced kudzu. I genotype the individuals at 670 SNPs and identify FST outliers that aid in varietal delimitations. I find clear genetic distinctions among the three morphologically overlapping varieties of P. montana and obtain a fine enough resolution to provide hypotheses for each US sample’s historical Asian origin.

Author

• Haynsen, Matthew Stephen

Language

• English

Keyword

• GBS
• Pueraria montana var. lobata
• Population genomics
• Population genetics
• kudzu
• invasive

Date created

• 2018

Type of Work

• Dissertation

License

• All rights reserved

Rights statement

• In Copyright

GW Unit

• Biological Sciences

Degree

• Ph.D.

Advisor

• Crandall, Keith A
• Egan, Ashley N

Committee Member(s)

• Orti, Guillermo
• Lill, John

Persistent URL

•  https://scholarspace.library.gwu.edu/etd/rj430553r