title: A Survey of Genetic Variation and Genome Evolution within the Invasive Fallopia Complex.
abstract: The knotweed taxa Fallopia japonica, F. sachalinensis and their interspecific hybrid F. × bohemica are some of the most aggressive invaders in Europe and North America and they are serious threats to native biodiversity. At the same time, they constitute a unique model system for the creation of hybrids and studies of the initiation of evolutionary processes. In the presented study, we focused on (i) examining genetic diversity in selected populations of three Fallopia taxa in the invaded (Poland) and native ranges (Japan), (ii) establishing genome size and ploidy levels and (iii) identifying ribosomal DNA (rDNA)-bearing chromosomes in all of the taxa from the invaded range. We found that the genetic diversity within particular taxa was generally low regardless of their geographical origin. A higher level of clonality was observed for the Polish populations compared to the Japanese populations. Our study suggests that the co-occurrence of F. sachalinensis together with the other two taxa in the same stand may be the source of the higher genetic variation within the F. × bohemica hybrid. Some shift towards the contribution of F. japonica alleles was also observed for selected F. × bohemica individuals, which indicates the possibility of producing more advanced generations of F. × bohemica hybrids. All of the F. sachalinensis individuals were hexaploid (2n = 6x = 66; 2C = 6.01 pg), while those of F. japonica were mostly octoploid (2n = 8x = 88; 2C = 8.87 pg) and all of the F. × bohemica plants except one were hexaploid (2n = 6x = 66; 2C = 6.46 pg). Within the chromosome complement of F. japonica, F. sachalinensis and F. × bohemica, the physical mapping of the rDNA loci provided markers for 16, 13 and 10 chromosomes, respectively. In F. × bohemica, a loss of some of rDNA loci was observed, which indicates the occurrence of genome changes in the hybrid.
authors: Department of Botany and Nature Protection, University of Silesia, Katowice, Poland.
authors: Katarzyna
authors: K
authors: Bzdega
authors: Department of Genetics, University of Silesia, Katowice, Poland.
authors: Agnieszka
authors: A
authors: Janiak
authors: Department of Environmental Stress Biology, Institute of Plant Genetics, Polish Academy of Sciences, Poznań, Poland.
authors: Tomasz
authors: T
authors: Książczyk
authors: Department of Botany and Nature Protection, University of Silesia, Katowice, Poland.
authors: Agata
authors: A
authors: Lewandowska
authors: Department of Botany and Nature Protection, University of Silesia, Katowice, Poland.
authors: Małgorzata
authors: M
authors: Gancarek
authors: Department of Plant Genetics, Physiology and Biotechnology, UTP University of Science and Technology, Bydgoszcz, Poland.
authors: Elwira
authors: E
authors: Sliwinska
authors: Department of Botany and Nature Protection, University of Silesia, Katowice, Poland.
authors: Barbara
authors: B
authors: Tokarska-Guzik
mesh_terms: D004275:DNA, Ribosomal / Q000235:genetics*; D019143:Evolution, Molecular; D000069263:Fallopia / Q000235:genetics*; D014644:Genetic Variation; D059646:Genome Size; D018745:Genome, Plant; D058865:Introduced Species; D007564:Japan; D010802:Phylogeny; D058974:Phylogeography; D020161:Physical Chromosome Mapping; D011044:Poland
chemical_list: D004275:DNA, Ribosomal