Genetic Dissimilarity in Conyza sumatrensis Revealed by Simple Sequence Repeat (SSR) Markers

Abstract

In view of the rapid evolution of Conyza sumatrensis populations resistant to glyphosate, it is necessary to understand the genetic diversity aimed to improve strategies for managing this weed. We investigated the genetic dissimilarity among 15 biotypes of C. sumatrensis from different geographic regions using microsatellite loci. The biotypes, were cultivated in a greenhouse to obtain vegetal material for DNA extraction. Nineteen microsatellite markers (SSR), were developed for C. sumatrensis biotypes. The genetic dissimilarity was estimated by the Jaccard coefficient (JC) and the biotypes grouped by the UPGMA method. The results demonstrated a high dissimilarity (JC = 7.14 to 82.62) of the analyzed material, with the biotypes forming five groups, being one group formed just by the susceptible biotype and in the others grouped by biotypes from distinct locations in the same group The high genetic diversity of C. sumatrensis indicates that the biotypes may show different responses to different management strategies, and that the mechanisms of resistance to herbicides and characteristics of evolution of populations due to adaptability may be some of the factors involved in the genetic variability of the species.

Mechanisms that may lead to high genetic divergence and to the invasive success of tall fleabane (Conyza sumatrensis; Asteraceae)

“…The invasive potential and rapid range expansion of C. sumatrensis have been attributed to its persistent fecundity and high germination rate (Hao et al 2009); its production of a large number of small, wind-dispersed seeds, ranging up to more than 200,000 seeds per plant (Sansom et al 2013); and its high resistance to diseases, herbivory, and herbicides (Santos et al 2014a). Santos et al (2014bSantos et al ( , 2015 reported differential sensitivity to herbicides according to the stage of development of the plants, while Schneider et al (2020) reported the overexpression of genes in the resistant biotype treated with glyphosate. Differential sensitivity to herbicides according to growth stage was also reported in C. canadensis and C. sumatrensis populations by Travlos and Chachalis (2013).…”

“…Despite the economic importance of C. sumatrensis, few studies have particularly addressed the traits of this weed species. Only some reproductive (Hao et al 2009) and morphological (Sansom et al 2013) features, the occurrence of biotypes resistant to herbicides (Santos et al 2014a(Santos et al , 2014b(Santos et al , 2015, the impact of invasions on the soil microbiome (Rasool et al 2016), and genetic diversity within and among different biotypes (Marochio et al 2017;Schneider et al 2020) have been reported so far. Genetic diversity analysis of weed populations has practical importance, such as in predicting population response to biological or chemical control (Ward et al 2008).…”

“…A high number of alleles at simple sequence repeats of DNA (SSR loci or microsatellite loci) and high levels of observed and expected heterozygosity have been reported in a few biotypes of C. sumatrensis from different invaded areas of southern Brazil (Marochio et al 2017). Genetic dissimilarity among 15 biotypes of C. sumatrensis from different fields from southern and midwestern Brazil determined using microsatellite loci was reported by Schneider et al (2020). However, there is no information on genetic diversity within each biotype.…”