Abstract Detail

Population Genetics/Genomics

Busby, Andrew [1], McCann, Caitlin E. [1], Laycock, William A. [1], Pate, Kayln N. [1], Hofford, Nate [1], Motley, M'Kayla [1], McKain, Michael [2].

Fine-scale variation of nuclear and chloroplast genomes in a Johnsongrass (Sorghum halepense) population.

Johnsongrass, or Sorghum halepense (L.) Pers. , is one of the world’s worst weeds, causing millions of dollars in crop loss annually. Johnsongrass exhibits a number of characters that enhance its invasiveness including allelopathy, production of copious amounts of seed, rapid growth, and the production of numerous rhizomes each growing season. Rhizomes, or underground stems, are capable of producing clonal offspring either through a maintained connection to the mother plant or through the fragmentation and spread of rhizomes. Clonal growth of populations through rhizomes is thought to be a major driver of success in this species, though continued clonal growth can create populations that are genetically depauperate and prone to extinction either through disease or decreased fitness in the wake of environmental variation. Transposable elements are a potential source of genetic novelty for clonal populations and may help to counteract the negative aspects of clonal growth. Here, we examine the chloroplast haplotype composition of a single population to determine levels of clonality, while exploring the dynamics of certain TE families among individuals of that population. Sampling was conducted using a transect-based approach built on 1x1 meter quadrats spaced at least 10 meters apart from each other. We assembled the chloroplast genome from a subset of our samples to identify the number of distinct haplotypes in this population. Using haplotype number and the genetic distance between haplotypes, we assessed the diversity of maternal lines contributing to the population. We further placed the chloroplast sequences into a larger Johnsongrass chloroplast phylogeny to identify other populations that may be closely related, and potential sources of gene flow to our focal population. We then estimated the abundance of Gypsy and Copia retroelements, the two most abundant TEs in the Johnsongrass genome. These data serve as a preliminary understanding of the impact of TEs on clonal genetic diversity. As we expand our sampling and whole genomes become available, we will be able to more accurately assess how transposable elements may be contributing to the evolution of Johnsongrass populations and better understand the dynamics of clonality in Johnsongrass populations.

1 - The University of Alabama, 500 Hackberry Lane, Box 870344, Mary Harmon Bryant Rm 411, Tuscaloosa, AL, 35487, United States
2 - University Of Alabama, 411 Mary Harmon Bryant Hall, Tuscaloosa, AL, 35487, United States

Keywords:
chloroplast
transposable elements
Population genomics
clonality.

Presentation Type: Poster
Session: P3, Population Genetics/Genomics Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PG006
Abstract ID:1008
Candidate for Awards:None