The Effect Of Microorganism And Climatic Factors On The Quality Of Panax Quinquefolium L.

Panax quinquefolium L.is a perennial herbaceous plant of panax genus and its roots used as medicine with high medicinal and economic value in China.At present,China has developed into the world’s largest P.quinquefolium consumer country and the third largest P.quinquefolium producing country in the world.However,the quality of P.quinquefolium in different cultivated areas in China was different.In this study,P.quinquefolium and its rhizosphere soil were used as research materials.Based on the microbiome,transcriptome and chloroplast genome technology,combined with climatic factors and soil physicochemical index,this study systematically studied microbiome of P.quinquefolium and the relationship among ginsenosides content in P.quinquefolium with microorganism,climatic factors and soil physicochemical properties.In addition,the distribution of P.quinquefolium under future climate was predicted and its plastid genome characteristics under current distribution was compared.The main results are:1.The high-throughput sequencing technology was used to study the rhizosphere soil microbial communities of P.quinquefolium from Beijing,Jilin and Shandong province and 2-,3-and 4-year-old P.quinquefolium from Shandong province.It was found that the bacteria in the rhizosphere soil were mainly composed of Actinobacteria,Proteobacteria,Acidobacteria,Firmicutes and Chloroflexi.Rhizosphere soil fungi mainly include Ascomycota and Basidiomycota.The core microbiota in the soil of three main producing areas of P.quinquefolium were Bacillus,Rhodanobacter,Sphingomonas,Fusarium,Plectosphaerella and Penicillium.The 8 biomarker genera in the rhizosphere soil communities of three producing areas of P.quinquefolium were RB41,Chaetomium,Bacillus,Arthrobacter,Burkholderia,Mortierella,Pseudogymnoascus and Tetracladium.The relative abundance of cold-adapted Pseudogymnoascus in the rhizosphere soil increased with the growth of P.quinquefolium.2.The high-throughput sequencing technology was used to compare the rhizosphere soil microbial communities of healthy and rot root of p.quinquefolium.Theα-diversity analysis showed that the Chao 1,ACE and Sob of rhizosphere soil fungi of root rot disease were lower than those of healthy roots.The physical and chemical properties of soil was also determined.The results showed that the pH,available phosphorus and available potassium contents of root rot of P.quinquefolium soil were lower than that of healthy P.quinquefolium.LEfSe showed that the relative abundance of six fungal genera in root rot soil,namely Gibellulopsis,Fusarium,Plectosphaerella,Tetracladium,Gibberella and Ilyonectria,was higher than that in healthy soil(P<0.05).Three of these genera(Ilyonectria,Plectosphaerella and Fusarium)can cause the rot root of p.quinquefolium.Gibellulopsis and Gibberella were found closely related to root rot ofp.quinquefolium for the first time.3.The high-throughput sequencing technology was also used to study the endophytic microbiome of P.quinquefolium from Beijing,Jilin and Shandong province and 2-,3-and 4-year-old P.quinquefolium from Shandong province.Moreover,the endophytic microbiome of the root and leaves of P.quinquefolium was compared.The results showed that the endophytic fungi were mainly from Ascomycota and Basidiomycota.The microbial α-diversity of leaves was higher than that of roots.It was found for the first time that Pseudogymnoascus,a cold-adapted microorganism,was the core microbiota of roots and leaves of P.quinquefolium from three main habitats with different growth years.The relative abundance of Fusarium increased with the growth years of P.quinquefolium.4.RDA analysis of ginsenosides content in P.quinquefolium with the relative abundance of microorganism,climatic factors and soil physicochemical properties showed that diurnal temperature difference(BIO2)was an important ecological factor affecting the ginsenosides content in P.quinquefolium,which could explain 86.2%of the observed variation.Moreover,the potted seedlings of 3-year-old P.quinquefolium were cultivated in artificial climate chamber for two month.It showed that the total ginsenosides content in P.quinquefolium was the highest under the day-night temperature of 25℃/25℃,followed by the day-night temperature of 25℃/15℃,and the lowest under the day-night temperature of 25℃/5℃.Transcriptome sequencing results showed that the differential genes were related with SQE,HMGR,HMGS and SS in ginsenoside biosynthesis pathway.5.MaxEnt model was used to predict the suitability of P.quinquefolium in China under current and future climate(2100),the suitable area of P.quinquefolium in China will expand and migrate to the northeast,and some suitable areas at present are no longer suitable for planting P.quinquefolium in the future.Comparing the chloroplast genomes of P.quinquefolium from the present suitable regions,24 single nucleotide polymorphisms and 6 insertions and deletions was found in the chloroplast genomes of P.quinquefolium.Phylogenetic analysis of chloroplast genome showed that P.quinquefolium were different from those from their original regions(the United States and Canada).RpcoC2,trnE-UUC,accD,petD,trnL-CAA,trnR-UCU,rps14 and psbB might be effective in distinguishing P.quinquefolium from different areas.