Phylogeny Research Of Prunus Triloba And Related Species Based On Chromosome Kayotype And Single-copy Nuclear Gene DNA Sequences

Prunus triloba is an important native plant in China. It is widely used for landscape and popular in Northern China because of its beautiful flowers and wide adaptability. As one of the most famous and traditional horticultural plants, Prunus triloba has a long cultivation history. Prunus triloba belongs to subfam. Prunoideae in Rosacea. The species in genus Prunus are often diploid (2n=2x=16). However, P. triloba is an octaploid species (2n=8x=64). The origin of this polyploidy species is still an unknown issue. In the present study, we focused on the phylogenetic position of P. triloba. Cytological and molecular phylogenetic (single-copy gene Leafy & RPB2) studies were conducted to investigate the relationships among P. triloba and related species.1. Analysis of karyotypes of Prununs triloba and four related species.The results showed that the optimum method was:marterials pretreated in 0.002mol/L 8-Hydroxyquinoline+0.02% Colchine mixture for 2.5h, dissociated in HCl:Absolute Alcohol=1:1 mixture at room temperature for 20-25 min, dyed with carbolic acid-magenta for 30-35min. To conclude, this method improved the efficiency and quality of chromosome sectioning.The karyotpes were analysed by the above method in Prunus triloba and four related species namely, P. persica L., P. mume Sieb.,P. cerasifera ’Pissardii’ and P. armeniaca L.. The results showed that the chromosomes number of cultivar p. triloba ’Zi Yan’ was 42, while other p, triloba materials’ numbers were 64 (2n=8x=64). The relative length component of P. triloba ’Zi Yan’ was 2n=6L+9M2+ 24M1+3S. All related species were diploid (2n=2x=16). Asymmetry index ranged from 57.68 to 63.08%. Among related species, P. triloba had the closet relationship with P. persica.2. Phylogenetic relationship between Prunus triloba and related species based on two intron sequences of nucleotide single-copy gene Leafy and RPB2According to former and present results, we could draw the following conclusions:(1) Chinese Amygdalus species could be divided into two groups:group one contains Prunu mira, Prunus kansuensis, Prunus ferganensis, Prunus persica, Prunus davidiana, Prunus communis and Prunus mongolica, and group two contains Prunus tenella/nana, Prunus triloba and Prunus pedunculata. (2) P. triloba ’Zi Yan’ may be originated as a hybrid, and one of its parents could be P. triloba and the other parent could be P. davidiana or Prunus salicina or other ralated species.