Analysis of pubescent oak (Quercus pubescens Willd.) by means of chloroplast DNA (cpDNA) in the western part of the Balkan Peninsula

Abstract

In the area of the western Balkans, xerothermal broad-leaf forests hold a very special position, the main species being pubescent oak (<em>Quercus pubescens</em> Willd.). The study comprises 36 populations of pubescent oak from Croatia, Bosnia and Herzegovina, Montenegro, Kosovo, Albania and Macedonia. Genetic variability and population diversity was analysed on chloroplast DNA in order to determine to which haplotype an individual or studied population belongs, as well as how they are related. For the detection of one haplotype analysed four sequences (AS, TF, DT and CD) on the chloroplasts DNA. The results of the analysis suggest that there are six different haplotypes of pubescent oak (2, 4, 5, 17, 31, 33) in the studied populations. Two more sub-haplotypes were found in haplotype 5 (a and b), but only in populations occurring in Croatia and Bosnia and Herzegovina. The results suggest the great variability of pubescent oak in the researched area, which is generally characteristic of other species from the area of the Balkan Peninsula. The results obtained by means of cpDNA analysis can help in the formation of seed zones. However, due to the strong selection pressure of unplanned logging, and the possible introduction of herbal material of unknown origin, it is necessary to find a sufficient number of autochthonous entities (i.e., populations of the researched species) as well as new suitable markers for their characterization. The results of this paper constitute a scientifically recognised, partial examination of the origin of the starting forest reproductive material from the broader geographic area, thus serving future projects on its regeneration

Does the genetic diversity among pubescent white oaks in southern Italy, Sicily and Sardinia islands support the current taxonomic classification?

“…Taking into account all the results of the work, the most plausible interpretation of the results is that all the oak populations sampled belong to a single oak taxon which is characterized by a large ecological and morphological amplitude. Although there is still no scientific certainty, the morphological and molecular pattern among pubescent white oaks evidenced in this paper, and those already shown in previous papers for other pubescent-oak populations from the central Mediterranean area (Franjic et al 2006;Viscosi et al 2009Viscosi et al , 2012Ballian et al 2010;Di Pietro et al 2016, 2020, increasingly reinforce the idea that this "single highly variable pubescent oak taxon" could be the result of repeated events of hybridisation and introgression between an ancient pubescent white oak species (which for simplicity we could here name Q. pubescens) and other European white oak species (e.g., Q. petraea, Q. frainetto, Q. robur). These events would have taken place continuously since the Tertiary and may have even intensified during the Pleistocene following the drastic paleogeographic and paleoclimatic events that characterized this Era.…”

Preliminary characterization of the Quercus pubescens complex in southern Italy using molecular markers

“…Several reports on the population genetics of the white oaks Q. robur L., Q. petraea, Q. pubescens have been published for south-eastern Europe in the last two decades (Franjić et al 2006, Curtu et al 2007a, Jerše and Batič 2007, Slade et al 2008, Curtu et al 2009, Ballian et al 2010, Enescu et al 2013. In Italy, only few data are available.…”

Tracing the origin and species identity of Quercus robur and Quercus petraea in Europe: a review

“…In the past, agarose or polyacrylamide gels were used for the screening of SNP variation through PCR-RFLP (BALLIAN et al, 2010;CURTU et al, 2007b;DEGUILLOUX et al, 2003bDEGUILLOUX et al, , 2004DUMOLIN-LAPÈGUE et al, 1998;GAILING et al, 2003GAILING et al, , 2009PETIT et al, 2002b;SLADE et al, 2008) or for microsatellite genotyping (BAKKER et al, 2003;DEGEN et al, 1999). Nowadays, separation on capillary sequencers allows multiplexing of up to 12 micrsatellite loci (ALBERTO et al, 2010;BUSCHBOM et al, 2011;DEGEN et al, 2010;DERORY et al, 2010;GAILING et al, 2007b;GUGERLI et al, 2007;GUICHOUX et al, 2011;HOELTKEN et al, 2012;LEPAIS and GERBER, 2011;VIDALIS et al, 2013), which reduces the genotyping costs and strongly improve the sensitivity in case of poor amplification.…”

“…Four universal cpDNA fragments have been extensively studied and has shown a longitudinal genetic differentiation resulting from postglacial colonization patterns over Europe (PETIT et al, 2002a, b; see also Table 1) as well as variation at the regional level (BALLIAN et al, 2010;BORDACS et al, 2002;COTTRELL et al, 2002;CSAIKL et al, 2002a, b;FINESCHI et al, 2002;JENSEN et al, 2002;KÖNIG et al, 2002;OLALDE et al, 2002;PETIT et al, 1997PETIT et al, , 2002cSLADE et al, 2008). Genotyping was strongly facilitated by the development of PCR-RFLP techniques, which avoids expensive Sanger sequencing for genotyping at particular SNPs (DUMOLIN-LAPÈGUE et al, 1998;PETIT et al, 2002b).…”