Low genetic diversity in an African invasive Poaceae in Brazil

Abstract

Poaceae has numerous species that are highly invasive thorough the planet. Urochloa, native to Africa, stands out in terms of invasion and impacts in South America. However, the correct identification of the species included in this genus is complex due to their morphological similarity with other species and there is a lack of studies involving the genetic variability of some species in Brazil, which is important for understanding the invasion mechanisms and planning control measures. In this study, we evaluated the genetic variability of the invasive exotic Poaceae Urochloa arrecta in different Brazilian regions, by using the nuclear marker ITS and the chloroplast marker trnL-trnF. The sequences obtained were compared with those available in GenBank (NCBI). The results indicated a low genetic differentiation among the sampled populations. Seven and ten distinct haplotypes were identified for ITS and trnL-trnF, respectively, and most specimens shared a single haplotype. These results indicate that a limited number of propagules were introduced in the invasive range and/or that this species reproduces mainly through asexual reproduction. This last possibility is suggested by the great regeneration and colonization rates of asexual propagules of this species. The data obtained are useful for understanding the invasion mechanisms of the group in the region.