Genetic diversity and phylogenetic analysis of Robinia pseudoacacia L. populations using ISSR markers, ITS1 and trnL-F intergenic spacer sequences

Robinia pseudoacacia L. is a deciduous tree planted almost all around the world for a wide variety of uses such as ornamental in urban ecosystems and forest trees in afforestation. This study aims to evaluate the genetic diversity and phylogenetic relations of R. pseudoacacia using some selected populations in Istanbul and Kocaeli cities. For this aim, molecular marker-assisted and DNA sequence-based analyses were performed. According to the results, nine of 15 inter simple sequence repeats (ISSR) primers gave clear and distinguishable bands with a total of 100 loci. The percentage of polymorphic loci (PPL) was calculated as 100% for multi-populations and ranged from 46% to 76% for single populations. Nei's gene diversity value was calculated between 0.165 and 0.251. The lowest and highest PPL were found in populations of Barbaros Boulevard and Dilovasi District, respectively. Population structure analysis showed seven different genetic structures for five populations. Internal transcribed spacer 1 region (ITS1) and trnL-F intergenic spacer region were used to examine the phylogenetic relationships of R. pseudoacacia, and both regions showed a high discriminative power at the family level. Based on the findings, R. pseudoacacia, as a forest tree residing in the urban ecosystem, may face the risk of population decline in the upcoming years due to its moderate/low genetic diversity and susceptibility to environmental pressures.