Genetic Diversity And Structure Of American Lotus (Nelumbo Lutea Willd.) In North America Revealed From Microsatellite Markers

Nelumbo lutea is also known as the yellow lotus and belongs to the Nelumbo in the Nelumbonaceae.This species is distributed in North America,including the central,eastern and the Great Lakes regions in the north of the United States.American lotus grows in waters of rivers,lakes,swamps or ponds,and huge beautiful flowers emerge above the water.American lotus is an important food source for native Americans and is also a popular ornamental plant in the world.However,its habitat is damaged by natural disaster and human activities.Little is known about the genetic diversity of this species.In this article,a total of326 samples from 19 American lutea populations were collected,12 pairs of SSR primers were used to evaluate their genetic diversity and genetic structure.The research results provide theoretical basis and practical references for the further utilization and protection of the germplasm resources of the American lotus.At the same time,molecular data were provided for the study of the genetic variation and differentiation among Nelumbo lutea populations.The main results of this study are as follows:1.The genetic diversity of American lotus at species level:A total of 141 different alleles were found in 19 populations of 12 SSR loci.Each locus producing 11 to 33 alleles（N_T）,and an average of 22.83 alleles per locus.The number of average effective alleles is 2.436.Shannon’s information index（I）,observed heterozygosity（H₀）,expected heterozygosity（H_e）and Nei’s genetic diversity index（H）is 0.873,0.320,0.469 and 0.811 respectively.The results showed that the polymorphism of SSR primers was good,and American lotus at species level has high genetic diversity.2.The genetic diversity of American lotus at populations level:Polymorphic loci percentage（PPL）,observed heterozygosity（H₀）,expected heterozygosity（H_e）,Shannon’s information index（I）,Nei’s genetic diversity index（H）were 89.04%,0.320,0.459,0.8730.461.The results indicated that a high genetic diversity of American lotus at populations level.According to the I and H,the genetic diversity of each populations ranked in descending order as PA（Pennsylvania）,GA（Georgia）,IL3（Illinois）,MO（Missouri）,FL3（Florida）,AL1（Alabama）,OH2（Ohio）,OH1（Ohio）,FL1（Florida）,IL1（Illinois）,MN（Minnesota）,IL2（Illinois）,OK（Oklahoma）,NC（North Carolina）,FL2（Florida）,VA（Virginia）,AL2（Alabama）,TN（Tennessee）,MD（Maryland）.3.The genetic differentiation among populations of American lotus:Molecular genetic variance analysis（AMOVA）showed that the variation among American lotus population accounted for 32%,the variation within population accounted for 68%,most of the variation existed in the population.The population of yellow lotus has reached a significant level.4.Mantel test showed that there was no significant correlation between genetic distance and geographical distance（r=0.001,p=0.380>0.05）.5.Neighbor-Joining Cluster Analysis nineteen American lotus populations were divided into four groups:FL1,FL2,IL1,NC,VA,AL1 and AL2 clustered together;OH1 and TN clustered together;FL3,OK,OH2,IL3,GA,PA and MO clustered together;MD,MN and IL2 clustered together.6.STRUCTURE ANALYSIS:When K=4,nineteen populations of American lotus came from four gene pools:FL1 and IL1 mainly came from a gene bank;OH1,TN,VA,NCand half of MO,OK mainly came from a gene bank;FL3,OH2,MD,MN,IL2,IL3,GA,PA and the other half of OK,MO mainly comes from one gene bank;FL2,AL1 and AL2 mainly come from one gene bank.The PCA analysis was consistent with STRUCTURE analysis.