Evaluation Of P.ginseng And P.quinquefolius Germplasm Resources And Molecular Marker Development

The genus Panax L.is an important group in the family Araliaceae,containing about 12 species,of which ginseng(Panax ginseng C.A.Meyer)and American ginseng(Panax quinquefolius L.)are valuable medicinal plants with a long history of cultivation history.In recent years,with the continuous increase of market demand,the rapid expansion of cultivation scale,frequent introductions and exchanges between different production areas,and differences in cultivation methods and environmental factors,resulted in the hybrid germplasm of P.ginseng and P.quinquefolius,and the quality of medicinal materials is uneven.Germplasm resources are the material basis of breeding,and the quality of the germplasm resources determines the yield and quality of P.ginseng and P.quinquefolius.It is of great significance to the introduction and seedling cultivation,the breeding of dominant varieties and the protection of resources of P.ginseng and P.quinquefolius.In this study,SSR molecular marker technology was used to analyze the genetic diversity of P.ginseng from different production areas and different fruit colors,and P.quinquefolius from different producing areas,and screened out a set of primers suitable for the research on the germplasm resources of P.ginseng and P.quinquefolius.The germplasm resources of different varieties of P.ginseng and P.quinquefolius from different producing areas were analyzed.Firstly,the phylogeny of Panax was investigated using nuclear gene and chloroplast genome data,and the sister group relationship between P.ginseng and P.quinquefolius were clarified.Subsequently,shallow whole genome sequencing of P.ginseng was carried out,and 180 pairs of primers were screened out,from which 15 pairs of polymorphic SSR primers were selected.Genetic diversity analysis of ginseng varieties with different fruit colors showed that the genetic diversity of red-fruit ginseng population was higher.The Neighbor-Joining cluster analysis showed that the red-fruit and yellow-fruit ginseng have obvious hybrid germplasm,and pick-fruit ginseng was clustered into a single branch and the germplasm resources were more purified.The results of Structure showed that the proportion of single genotype in pick-fruit ginseng was relatively high,and the populations of red-fruit and yellow-fruit ginseng were rich in genotypes,and there was obvious hybrid germplasm in both types.The AMOVA analysis revealed that the genetic variation mainly occurred among individuals within populations,less occurred among populations,and the homogenized among different populations was obvious.Therefore,pink-fruit ginseng population may contain rare genotypes,which is the gene source of breeding new varieties with high quality,high yield,multi-resistance and genetic improvement,and also the material basis for the sustainable development and utilization of germplasm resources.LC-MS was carried out on ginseng varieties of different fruit colors,and the metabolites of different germplasm were compared.The PCA results showed that the pick-fruit ginseng was clustered together,and others were not strictly clustered.The results of OPLS-DA analysis showed that all kinds of ginseng samples were successfully divided into two categories,which was consistent with the results of PCA analysis,indicating that the differences within each group were small and the differences between groups were large.Combined with PCA and OPLS-DA analysis results,91,96,73 and 58 differential metabolites were screened out by group comparison.Further screening of characteristic differential metabolites of pick-fruit ginseng was carried out,and 21 characteristic differential metabolites were obtained.Proline,L-proline,L-ornithine,L-arginine showed a consistent downward trend,and Riboflavin and Cannabidiol showed a significantly consistent up-regulation trend.The results indicated that some cultivars had characteristic differential metabolites which could be used as potential indicators.In this study,7 pairs of SSR primers with better polymorphism were selected out for germplasm of P.quinquefolius from different producing areas,and the experimental data were counted to analyze their genetic diversity and genetic differentiation.The results showed that there was obvious homogenization and germplasm hybridisation among P.quinquefolius populations from different producing areas.AMOVA analysis showed that 99% of the genetic variation occurred among individuals within the population,and there was almost no genetic differentiation among populations.The Neighbor-Joining cluster analysis showed that each population did not cluster into a single lineage.The STRUCTURE analysis showed that there were the same genotypes and similar proportions among varieties and populations.These results fully revealed the homogenization cultivated P.quinquefolius populations and germplasm hybridization within populations.The genetic structure of cultivated P.quinquefolius may be related to the insufficient artificial breeding time,and further variety purification is needed.