Diversity Analysis of Polyporus umbellatus in China Using Inter-simple Sequence Repeat (ISSR) Markers

Polyporus (P.) umbellatus, an endangered medicinal fungus in China, is distributed throughout most areas of the country. Thirty-seven natural P. umbellatus samples collected from 12 provinces in China were subjected to the inter-simple sequence repeat (ISSR) assay to investigate the genetic diversity within and among the 11 natural populations. Nine ISSR primers selected from 100 primers produced 88 discernible DNA bands, with 46 being polymorphic. The frequency of polymorphism varied from 19.57 to 93.48% with an average of 61.26% across all populations. At the population level, the within-population variance was much greater (92.04%) than the between-population variance (7.96%) as revealed by analysis of molecular variance. Eleven P. umbellatus populations were grouped into two major clusters, and the clustering pattern displayed four groups using the unweighted pair-group method with an arithmetic mean dendrogram. Principal coordinate analysis further indicated that the genetic diversity of P. umbellatus strains was unevenly distributed and displayed a clustered distribution pattern instead. Within these clusters, subgrouping (Henan and Hubei) and cluster II (Jilin and Heilongjiang) related to the geographic distribution were evident. The present study provides the first global overview of P. umbellatus diversity analysis in China, which may open up new opportunities in comparative genetic research on this medicinal fungus in other countries.