Genetic Consequences of Hybridization in Relict Isolated Trees Pinus sylvestris and the Pinus mugo Complex

Abstract

Scots pine (Pinus sylvestris L.) and the taxa from the P. mugo complex can hybridize in the contact zones and produce fertile hybrids. A unique example of an early Holocene relict population of P. sylvestris and P. uliginosa (a taxon from the P. mugo complex) growing on the tops of Jurassic sandstone rocks is located in Błędne Skały (Sudetes). Phenotypically, there are trees resembling P. sylvestris, P. uliginosa and intermediate forms between them. We expected that some of P. sylvestris and/or P. uliginosa-like trees could be in fact cryptic hybrids resembling one of the parental phenotypes. To address this question, we examined randomly sampled individuals, using a set of plastid (cpDNA), nuclear (nDNA) and mitochondrial (mtDNA) markers as well as biometric characteristics of needles and cones. The results were compared to the same measurements of allopatric reference populations of the P. sylvestris and the P. mugo complex (Pinus mugo s.s, P. uncinata and P. uliginosa). We detected cpDNA barcodes of the P. mugo complex in most individuals with the P. sylvestris phenotype, while we did not detect cpDNA diagnostic of P. sylvestris within P. uliginosa-like trees. These results indicate the presence of cryptic hybrids of the P. sylvestris phenotype. We found only three typical P. sylvestris individuals that were clustered with the species reference populations based on needle and cone characteristics. Most trees showed intermediate characteristics between P. sylvestris and P. uliginosa-like trees, indicating intensive and probably long-lasting hybridization of the taxa at this area and subsequent gene erosion of parental species.

Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

“…Our data indicate that the pattern of introgression is not symmetric between taxa, and in general, stronger gene flow was estimated from representatives of the P. mugo complex to P. sylvestris than in the opposite direction. Earlier studies reported such asymmetric ongoing gene flow within present-day contact zones of P. uliginosa, P. mugo, and P. sylvestris [79][80][81]. Surprisingly, the strength of gene flow within the P. mugo complex is not consistent considering the genetic relatedness between the taxa-in fact, P. mugo and P. uncinata are characterized by the lowest reciprocal migration rates among all analyzed species.…”

“…The wide distribution of P. sylvestris and its known long-distance migration associated with postglacial recolonization of Europe could facilitate overlap with other pine species and locally restricted gene flow. Previous studies reported similarities between Scots pine populations from Poland and Finland [85,86], reflecting their common phylogeographic history, and mitotype sharing between P. uliginosa, P. mugo, and P. sylvestris in their contact zones was also reported [33,80].…”

Phytosociological Analysis of Natural and Artificial Pine Forests of the Class Vaccinio-Piceetea Br.-Bl. in Br.-Bl. et al. 1939 in the Sudetes and Their Foreland (Bohemian Massif, Central Europe)

“…Another species recorded in these phytocoenoses is subalpine Pinus mugo Turra and its hybrids with P. sylvestris-P. x rhaetica (=P. uliginosa Neumann) [66,67]. The herb layer is composed of rare in the study area species of boreocontinental range type (Empetrum nigrum L., Vaccinium uliginosum).…”

Uplift capacity evaluation of light-framed wood structure’s roof-to-wall connections

“…Pinus sylvestris L. is widely distributed in Russia, Turkey, Mongolia, and the Greater Khingan Mountains Forest region of China. It has strong cold-resistance capability and does not require rich soil moisture conditions; thereby, it is capable for utilization as an afforestation tree species in mountainous and sand dune areas (Ekman et al 2002;Korkut et al 2008;Arriaga et al 2012;Cai et al 2016;Buyuksari et al 2017;Burawska-Kupniewska et al 2019;Sarkhad et al 2020;Sobierajska et al 2020). Pinus sylvestris L. has various apparent material performance, such as straight texture, clear pattern, moderate uniform structure, lightweight performance, low density, distinct rosin smell, high water resistance, high moisture resistance, good antifungal corrosion, and high durability, so it is mainly used in structural materials, and is also widely used in other wood production fields (Megnis et al 2002;Yildiz et al 2004;Rautiainen and Alen 2007;Temiz et al 2008;Simsek et al 2010;Bekhta et al 2014;Witomski et al 2014;Shen et al 2020).…”