Study On Polyploid Origin And Evolution Of Platycladus Viridis Using LFY Gene

Polyploidy plays an important role during the evolution of plants, and it occurs inmost of flowering plants, It is common that recurrent polyploidy and severalevolution of polyploidy among all plants. Based on the origin, alloploids andautoploids are recognized. The former from among different species, whereas thelatter form same species, typically involving crossing between individuals.The Parakmeria of Magnoliaceae is perennial tree plant, which is endemic inChina. It contains fives species, mainly distributed in Yunnan, Guizhou, Hunan,Guangxi, Sichuan and Guangdong area. Polyploidy plants has a certain correlationwith their geographical distribution. The distribution areas of diploid species isrelatively narrow and the ecological environment is relatively simple, which lead tosome species have even become endangered species, however polyploid speciesdistribution is relatively large. In this study we used the leaves of all five recognizedspecies as research material, and made analysis on low-copy nuclear genes LFYsequence of15populations by the method of cloning and sequencing. The mainpurpose is to investigate the origin and evolution of polyploid, infer the relationshipbetween diploid and polyploid in Parakmeria.The phylogenetic analysis of low copy nuclear gene sequences indicated that clonesequence of one ploidy population is relatively large, which probably derived fromdifferent plant families. Phylogenetic tree found that P. omeiensis is a hybrid betweenP. nitida and P. kachirachirai, but who is its paternal and maternal need to be furtherexamined. P. lotugensis and P. yunanensis are the products of several hybridizationsand polypoidiztions. We suggested that hybridization and poluploidization are themost important mechanism in the diversification of Parakmeria. The polyploidypopulations were more closely related, indicating that significant geneticdifferentiation may have occurred between diploids and polyploids. The geographicdistribution of diploids and polyploids in Parakmeria may be associated with the pastecological environments of different areas, especially during the glacial period.