Genetic diversity of phalaris arundinacea populations in relation to river regulation in the Merkys basin, Lithuania

Abstract

During the 1950s-1960s, the Merkys river basin, the largest protected area of Lithuania, underwent severe anthropogenic regulations. Within the Baltic States, the genetic diversity of Phalaris arundinacea populations is unknown and how they might be affected by anthropogenic activities such as river regulation. The objectives of this study were to compare molecular parameters (SSRs or microsatellite loci) within and among populations from natural river fragments with populations from regulated river parts. Study populations have greater genetic diversity within, rather than among, populations. The upstream portion of the Merkys basin populations had lower genetic diversity compared with further downstream. The mean number of polymorphic SSR loci was lower for populations from regulated parts of the river basin compared with natural ones. Main principle coordinate analysis revealed populations of regulated rivers at marginal positions. Bayesian clustering showed that current populations are admixtures of 3 distinct genetic groups, based on STRUCTURE analysis (K = 3 groupings) in geographic subdivisions of (a) downstream populations (Varėnė, Verseka, Upper Grūda, Lower Grūda, Upper Merkys, Lower Merkys), (b) upstream populations (Upper Šalčia, Beržė, Lower Šalčia, Visinčia, Lower Šaltykščia, Nedilė), and (c) the 2 regulated sites in the distinct geographic area of Taurupis and Upper Šaltykščia.P. arundinacea in the Merkys river basin does not all belong to a single, random-mating population encompassing its tributaries or among populations across its geographic scales. In several instances, river regulation might impair the genetic diversity of P. arundinacea populations.

Relationship Between Genetic and Environmental Characteristics of Lithuanian Populations of Purple Loosestrife (Lythrum Salicaria)

“…For analyses at each site 6 plants were collected, selecting individuals growing >15 m apart. Fully developed, healthy (without visible mechanical or biotic damages) leaves from the upper part of the main axis of L. salicaria were collected as it is done earlier with some other perennial herbs (Anderson et al, 2018). Leaves of the plants were enclosed into separate bags and within cool box transported to the laboratory, until DNA extraction keeping specimens frozen.…”

“…Already three decades molecular methods remain among the most reliable tools for information sets about population diversity issues (Guichoux et al, 2011). Inter simple sequence repeats (ISSR), microsatellites (SSR) and amplified fragment length polymorphism (AFLP) markers are the most frequently used tools for examination of genetic diversity of populations of macrophytes (Lambertini et al, 2010;Anderson et al, 2018;Vyšniauskienė et al, 2020;Fan et al, 2021), as well as for detection of introgression (Bradley et al, 2013;Butkuvienė et al, 2017), linking phenotyphic plasticity to genetic variation (Wennersten & Forsman, 2012;Forsman, 2014). Before initiation of present study, American populations of L. salicaria were tested employing AFLP markers, and related data concerning genetic diversity of this species in Europe were limited to West regions (Houghton-Thompson et al, 2005;Chun et al, 2009).…”

“…Pollen and seed dispersal of riparian vegetation is strongly related to the watercourse (Nazareno et al, 2021). Only pilot studies have been done examining genetic diversity differences of riparian populations depending on river basins, land use type, or river regulation (Lamote et al, 2002;Anderson et al, 2018).…”

Variability in ITS1 and ITS2 sequences of historic herbaria and extant (fresh) Phalaris species (Poaceae)

“…While minor variation, i.e., plant height and biomass, exists due to genetic and environmental factors, both the native P. arundinacea North American types and those native to Eurasia are virtually indistinguishable for any morphological trait [ 31 ], since all possess ligules [ 7 ] and the same floret type, “Floret Type 4” [ 15 ], although the floret type cannot be used when collecting vegetative genotypes for analyses. The North American and Eurasian types (using both extant and historic or herbaria specimens) have been separated, however, using biochemical (allozymes) [ 28 ] and molecular markers, such as ISSRs (inter-simple sequence repeats) [ 32 ], AFLPs (amplified fragment polymorphisms) [ 33 – 35 ], SNPs (single nucleotide polymorphisms) [ 29 , 36 ], as well as ITS regions [ 11 , 15 , 19 , 20 ].…”

Variability in ITS1 and ITS2 Sequences of Historic (herbaria) and Extant (fresh) Phalaris Species

“…exists due to genetic and environmental factors, both the native P. arundinacea North American types and those native to Eurasia are virtually indistinguishable for any morphological trait [31], since all possess ligules [7] and the same oret type, "Floret Type 4" [15], although the oret type cannot be used when collecting vegetative genotypes for analyses. The North American and Eurasian types (using both extant and historic or herbaria specimens) have been separated, however, using biochemical (allozymes) [28] and molecular phylogenetic markers, such as ISSRs (inter-simple sequence repeats) [32], AFLPs (ampli ed fragment polymorphisms) [33][34][35], SNPs (single nucleotide polymorphisms) [29,36], as well as ITS regions [11,15,19,20].…”