Phylogenetic Origin Of Pingguoli Inferred From Its And Psba-Trnh Sequences

In order to clarify the controversy of Pingguoli for years, this study selects Pingguoli in Yanbian area as material. The relationship between Pingguoli and related Pyrus cultivars were analyzed by using ITS and psbA-trnH, in order to provide molecular basis for determining position of Pingguoli, the main findings are as follows:For the first time, we clone ITS and psbA-trnH sequences from Pingguoli, obtain three functional ITS sequences, namely, KC895396,, KC895397, KJ011895, and two ITS pseudogene sequences, namely, KJ011896and KJ011897, and one kind of psbA-trnH sequence, its GenBank accession number is KF657740.The results of multiple sequence alignment show that there is a18bp deletion in5.8S region of the ITS pseudogene, this is the pretty biggest difference between functional ITS and non-functional ITS sequences. After the analysis of secondary structure of ITS2, the results show that the minimum free enegy of ITS2region between ITS functional genes and pseudogenes is significantly different, this can be used to distinguish ITS functional genes and pseudogenes.ITS phylogenetic tree shows that ITS functional gene and pseudogene sequences clusters separately. In the functional ITS cluster group, the Oriental pears and the Occidental pears cluster into two monophyletic group, independantly. The result of phylogenetic analysis in functional ITS sequences shows that Pingguoli presents close relationship with Pyrus. ussuriensis. After analysis of the non-functional ITS sequences, we find that Pingguoli has an evolution tendency to independent species. Evidence of psbA-trnH presents that Pingguoli has a priority to clustering with Pyrus. pyrifolia., shows that maternal of Pingguoli comes from Pyrus. pyrifolia..Combining evidences of ITS and psbA-trnH, this study suggests that Pingguoli is the hybrid of Pyrus. pyrifolia. and Pyrus. ussuriensis., the maternal of Pingguoli comes from Pyrus. pyrifolia., while the paternal of Pingguoli comes from Pyrus. ussuriensis., and it has an evolution tendency to independent species.