The Adaptive Evolution Mechanisms Of Heavy Mental Tolerance In Phytolacca Americana L.

Living in different concentrations of heavy metals for a long term,plants may produce a different tolerance or accumulation of ecological types.Manganese and cadmium hyperaccumulator plant(Phytolacca americana L.)as the object of this study,explore the molecular genetic mechanisms of heavy metal hyperaccumulator plants adapted to polluted environmental by heavy metals under population level.Pollution evaluation by 15 populations of P.americana collected in the field.According to the pollution characteristics of sampling points,the pokeweed populations are divided into non-polluted populations,manganese-polluted populations and cadmium-polluted populations.Analysis the tolerance and accumulation ability of different populations of pokeweeds by using the method of common garden experiment.Populations of P.americana from Mn-polluted area have a significant difference between plants from non-polluted area,such as plant height,leaf length.While the Mn accumulation of Mn-polluted area populations and non-polluted area populations had no significant difference.Plant from Cd-polluted area also have a significant difference between plants from non-polluted area under Cd treatment.And the Cd accumulation of Cd-polluted plants was significantly greater than that plants in non polluted area.The field sampled of 15 populations using the AFLP method analysis of population genetics.According to PcoA,NJ and Structure found that 15 of pokeweed populations were divided into 3 groups.The groups and habitat types of polluted-area are consistent.Therefore the different heavy metal polluted-habitat resulted in genetic differentiation of populations of P.Americana.At the same time,the wild populations of P.americana by MSAP method for epigenetic analysis,the corresponding individual seed planted in the greenhouse with common garden experiment under control,Mn,Cd treatment.The results showed that the highest level of methylation of the population in the field conditions,The results showed that the highest methylation levels of populations under field conditions,common garden control treatment are second,Cd and Mn common garden treatment are the lowest.The PcoA of the field populations were analyzed by MSAP data.The results showed that 15 populations could be divided into 3 groups.The grouping situation was consistent with the classification of the habitat types and AFLP results.PcoA analysis was conducted on the Mn-polluted populations in the field,the control treatment groups and Mn treatment groups under common garden experiment were analyzed by MSAP date.Results from field populations were clustered together,and common garden treatment population of long distance.Common garden experiment under control treatment groups and Mn treatment groups were together,but these two groups are closer and overlaps.PcoA analysis of Mn-polluted populations and in non-polluted population under common garden treatment by MSAP date.The results show that in the control treatment under common garden,non-polluted plants and Mn-polluted plants were clustered into two groups,and there is overlap between two groups.When Mn treatment,plants from non-polluted area and Mn-polluted area also gathered into two groups,and the distance is closer.MSAP results of common garden Cd treatment were similar with Mn treatment.The wild populations from Cd-polluted area were gathered together,populations from common garden were far distance.Control treatment of different populations become close,Cd treatment in different populations become closer.Transcriptome and digital gene expression sequencing of pokeweed leaves from different treatment through high-throughput RNA-seq sequencing technology.The differentially expressed genes in Mn and Cd stress were 88 and 100 significant enrichment KEGG pathways.In comparison,there are only two common pathways.Then compare the difference of the 20 GO enrichment types between the two treatments,it can be found that the 16 types are the same in the two treatments.The results show that Cd and Mn treatments have similar GO function types,but the KEGG pathways are not same.The leaves of Pokeweed were detected to obtain a large number of proteomics data under different treatment by mass spectrometry.It was found that there were a large number of differentially expressed proteins in the treatment of manganese and cadmium,and each treatment have 64 and 48 differentially expressed proteins,and the two treatments have 21 common proteins.Under field conditions,regardless of geographic distance and isolation between the populations of P.Americana,the effects of genetic and epigenetic evolutionary direction is mainly affected by the different types of pollution.Different types of pollution make the plants suffer different stress,thus forcing the pokeweed evolve toward more tolerance.