Development Of Single-copy Nuclear Gene Markers And Phylogeographic Study Of Typha Latifolia

Typha latifolia is a common species in the genus Typha,which is mainly distributed in the northern temperate to subtropical regions of Eurasia and North America.Although there are many studies on the genetic diversity of Typha latifolia,the geographical scale of these studies is relatively small.There are also a few studies to explore the intercontinental dispersal route of Typha latifolia,but so far the origin,divergence time and dispersal pathway of the intercontinental discontinuity of Typha latifolia are poorly understood.In this study,we first collected samples of Typha latifolia in Eurasia and North America,then developed single-copy nuclear gene markers based on transcriptome sequencing,next studied the genetic diversity and genetic structure of Typha latifolia,and finally explore the origin,population divergence time and dispersal pathway of Typha latifolia.The main results are as follows:1)We analyzed the transcriptome data of Typha latifolia.Based on the the transcriptome data,we successfully developed 14 single-copy nuclear genes molecular markers,which are suitable for the geographical study of Typha latifolia.2)The average haplotype diversity of 14 single-copy nuclear genes was 0.499 and the average nucleotide diversity was 0.0019,which indicated that the level of genetic diversity of Typha latifolia was not low.The genetic diversity of Asian population was slightly higher than that of European population,while that of North American population was much lower,less than half of that of European population.3)AMOVA analysis showed that 34.78% of the genetic variation of Typha latifolia existed among continents,indicating significant genetic differentiation among populations in Europe,North America and Asia.4)The posterior probability of multiple scenario models calculated by DIY-ABC supported the dispersal route of Typha latifolia from Europe to North America and to Asia,respectively.Estimation of differentiation time indicated that the divergence between European population and North American population occurred about 11.88 million years ago in the middle Miocene,and that between European population and Asian population occurred 4.23 million years ago in the early Pliocene.We thus inferred that the possible intercontinental dispersal path of Typha latifolia was from Europe to North America via North Atlantic Land Bridge in the middle Miocene,and from Europe eastward to Asia in the early Pliocene.The transcriptome data of this study will provide important genetic information for other studies of Typha genus,and single-copy nuclear genes may be used in other Typha species.The results reported in this study can deepen our knowledge of the genetic variation and intercontinental dispersal of Typha latifolia,and also provide a case for the study of the evolutionary history of widespread species of aquatic plants in the northern temperate zone.