Analysis Of Genetic Relationship Of Magnoliaceae Based On ISSR

The Magnoliaceae,which was first found in the Cretaceous or Jurassic of Mesozoic,is a relatively ancient group of angiosperms.It contains a lot of original information,which is of great significance to the study of the origin and phylogeny of flowering plants.This research use Central South University of Forestry and Technology institute of rare plants and South China Botanical Garden,Langshan Rare Plant Research Institute built three Magnoliaceae in plant germplasm resource collection,conservation of 11 genera and 135 species of Magnoliaceae plants resources,using ISSR molecular markers for genetic diversity and genetic relationship analysis,comparison and the genetic differences between,and the system position of magnoliaceae genus and subordinate groups were discussed,in order from the molecular level to the system classification and other research of magnoliaceae plants to provide experimental basis.The main results are as follows:(1)The improved CTAB method is based on the conventional CTAB method,and the plant genomic DNA extraction kit provided by Tiangen Biochemical Technology(Beijing)Co.,Ltd.is used for purification.It has a good extraction effect on the samples that are difficult to be extracted by the kit method,and can effectively reduce the extraction time of the CTAB method.The DNA extracted by this method has high purity,good integrity and high DNA concentration,which can meet the requirements of ISSR analysis.(2)Using the optimized reaction system,10 primers with high polymorphism and good repeatability were screened out for ISSR-PCR amplification of Magnoliaceae.The percentage of polymorphic loci was 100%.The observed number of alleles(Na)was 2.0000,the effective number of alleles(Ne)was 1.5335,the gene diversity(H)was 0.3256,and the Shannon diversity index(I)was 0.4956.The results indicated that the genetic diversity of Magnoliaceae was generally high.(3)using PopGen 32 statistical analysis software package,Liu Yu pot classification system 11 genera and 135 species of magnoliaceae plants in genetic diversity index is 0.3767,belongs to the genetic diversity within(Hs)is 0.1257,belongs to the genetic diversity between(Dst)is 0.2510,coefficient of gene differentiation(Gst)was 0.6662,that Liu Yu pot of classification is a larger genetic differentiation between in the system.The gene flow(Nm)between genera was 0.2505,much less than 1,indicating that the gene flow among genera was low,which was prone to genetic drift and accelerated genetic differentiation among genera.The total population gene diversity(Ht),intra-population gene diversity(Hs)and inter-population gene diversity were 0.3568,0.2498 and 0.1070 for 11 Magnoliaceae groups.At the species level,70.03%of the genetic variation existed within groups,and 29.97%of the genetic variation existed between groups.The intra-group genetic variation was significantly higher than inter-group genetic variation.The genetic variation among each group was small,and the gene differentiation coefficient(Gst)was 0.2997.The gene flow(Nm)was 1.1681 and greater than 1,indicating that the Magnoliaceae group had high gene mobility without genetic drift,indicating that each group had high genetic stability.The comparison of the classification of Liuyuhu system shows that the genetic variation among the magnoliaceae plants is concentrated into the groups,which enhances the communication among the groups and maintains the genetic stability of each group.(4)11 genera of Nei's genetic distance range between 0.0061?0.6735,genetic consistency range between 0.5099?0.9939,The genetic distances of Magnolia,Manglietia,Michelia,and Parakmeria were smaller than 0.1,and the genetic consistency was higher than 0.94,indicating that the genetic differentiation degree of Magnolia,Manglietia,Michelia,and Parakmeria was smaller and the genetic relationship was relatively close.The UPGMA clustering relationship of the 11 genera showed that the Magnoliaceae originated from the genera Talauma at the earliest,and evolved successively into the genera Paramichelia,Tsoongiodendron,Woonyoungia,Manglietiastrum and Liriodendron,Parakmeria,Manglietia,Michelia and Magnolia.The Nei's genetic distance of 11 Magnoliaceae groups ranged from 0.0245 to 0.3735,and the genetic consistency ranged from 0.6883 to 0.9758.?,?,?,?,? and ?genetic consistency is higher,more than 0.91,indicates that this evolution is closely related to the six;11 groups of UPGMA cluster analysis showed that the groups I formed a separate,distinct groups.Close genetic relationship.Clustering results generally support the division of Magnoliaceae into two subfamilies.