High levels of gene flow and genetic diversity in Irish populations of Salix capreaL. inferred from chloroplast and nuclear SSR markers

Abstract

BackgroundSalix caprea is a cold-tolerant pioneer species that is ecologically important in Europe and western and central Asia. However, little data is available on its population genetic structure and molecular ecology. We describe the levels of geographic population genetic structure in natural Irish populations of S. caprea and determine the extent of gene flow and sexual reproduction using both chloroplast and nuclear simple sequence repeats (SSRs).ResultsA total of 183 individuals from 21 semi-natural woodlands were collected and genotyped. Gene diversity across populations was high for the chloroplast SSRs (HT = 0.21-0.58) and 79 different haplotypes were discovered, among them 48% were unique to a single individual. Genetic differentiation of populations was found to be between moderate and high (mean GST = 0.38). For the nuclear SSRs, GST was low at 0.07 and observed heterozygosity across populations was high (HO = 0.32-0.51); only 9.8% of the genotypes discovered were present in two or more individuals. For both types of markers, AMOVA showed that most of the variation was within populations. Minor geographic pattern was confirmed by a Bayesian clustering analysis. Gene flow via pollen was found to be approximately 7 times more important than via seeds.ConclusionsThe data are consistent with outbreeding and indicate that there are no significant barriers for gene flow within Ireland over large geographic distances. Both pollen-mediated and seed-mediated gene flow were found to be high, with some of the populations being more than 200 km apart from each other. These findings could simply be due to human intervention through seed trade or accidental transportation of both seeds and pollen. These results are of value to breeders wishing to exploit natural genetic variation and foresters having to choose planting material.

Genetic structure of dioecious and trioecious Salix myrsinifolia populations at the border of geographic range

“…Van Puyvelde and Triest (2007) showed low gene flow in S. alba that was restricted to distances of 1-3 km. On the contrary, Perdereau et al (2014) reported a high gene flow in S. caprea to distances over 200 km. Thus, we cannot expect one pattern of genetic variation in large and variable Salix genus, which is capable of both sexual and asexual reproduction.…”

Assessing genetic diversity and population structure of <i>Salix viminalis</i> across Ergun and West Liao basin

“…In this study, a moderate to high level of polymorphism for the 20 SSR markers indicates that they are effective to reveal genetic variation of S. viminalis. An average number of 16.45 observed alleles (N a ) and 5.38 effective alleles (N e ) per locus within 330 individuals was higher than studies in Salix like S. caprea (N a = 10.00, N e = 3.90) (Perdereau et al 2014), and S. viminalis in Czech Republic (N a = 13.46, N e = 3.73) (Trybush et al 2012). Relatively high value of observed heterozygosity (H o ) (0.64) and H e (0.74) are comparable to the diversity of Populus nigra (H o = 0.70, H e = 0.73) (Rathmacher et al 2010) and S. viminalis (H o = 0.55, H e = 0.56) (Berlin et al 2014).…”

Genetic analysis of Latvian Salix alba L. and hybrid populations using nuclear and chloroplast DNA markers

“…Genotyping was carried out using nuclear SSR markers SB243, SB93, SB38, SB80, SB201, SB24, SB194 and SB199, which were reported to be informative in a range of Salix species (Barker et al 2003). Six angiosperm chloroplast markers ccmp2, ccmp4, ccmp6, ccmp10, ccmp7 and ccmp3 were also utilised (Weising & Gardner 1999), which had previously been used to analyse S. caprea (Palmé et al 2003, Perdereau et al 2014. The PCR reactions were multiplexed as follows: set A (SB243, SB93, SB38); set B (SB80, SB201); set C (SB24, SB194, SB199); set D (ccmp2, ccmp3, ccmp10); set E (ccmp 4, ccmp6, ccmp7).…”

“…Various kinds of DNA markers have been used to analyse Salix species, including dominant markers such as AFLPs, ISSR and RAPDs (Meneghetti et al 2007), as well as co-dominant markers such as SSRs (Perdereau et al 2014). Salix species have also been extensively studied with maternallyinherited chloroplast markers (Palmé et al 2003, Perdereau et al 2014, which enables the differentiation of lineages, as well as the direction of hybridisation.…”

“…Salix species have also been extensively studied with maternallyinherited chloroplast markers (Palmé et al 2003, Perdereau et al 2014, which enables the differentiation of lineages, as well as the direction of hybridisation. S. alba and S. fragilis are both polyploids, with S. alba reported as being stably tetraploid (Håkan-sson 1955), and S. fragilis being mainly tetraploid, but with other ploidy levels also identified (Barcaccia et al 2003).…”