Study On Microbe Of Rehmannia Glutinosa Soil By Metagenomics

Rehmannia glutinosa Libosch.is a perennial medicinal plant.It is one of the bulk medicinal materials in China.It has high medicinal and economic value.It is known as "Huai Di Huang" because of its excellent medicinal properties that grown in Wen County,Jiaozuo City,Henan Province.Due to the serious continuous cropping obstacles in Rehmannia glutinosa planting,the land cannot be replanted within 8-10 years after planting Rehmannia glutinosa,otherwise there will be many problems such as "blight,Root rot,root the tubers cannot expand normally,the yield is lower and poor efficacy" and so on.In this study,the soil of Jiaozuo Wenxian in“Huai Di Huang” production area was taken as the research object.In this study,the effects of soil fungi on Rehmannia glutinosa were studied by means of soil fungi separation and reconnection.For the first time,the dynamic changes of soil microbial community structure in 1-10 years after planting Rehmannia glutinosa were analyzed by means of metagenomic molecular sequencing,and the process of self-healing of soil microbial communities after planting Rehmannia glutinosa was explored.The research results are as follows:1.This study compared the isolation effect of PDA medium,Bengal red medium,Malt extract medium,Salmon medium,Martin's medium 5 fungi on the soil fungi isolated from Rehmannia glutinosa planted 1-10 years apart.The results showed that the isolation ability of 5 kinds of media to soil fungi was PDA medium > Bengal red medium > malt extract medium > sand medium > malting culture medium.After planting the Rehmannia glutinosa,a total of 124 strains of fungi were isolated from the soil a year later,far higher than that of 24 strains after ten years interval,and soil with different interval years.The number of fungi isolated decreased with the increase of separation years.The results showed that the PDA medium was the most conducive to the isolation of fungi from Rehmannia glutinosathe,the number of fungi isolated from soil planted with Rehmannia glutinosa increased.2.The fungi were taken as the research objects.The plant size,plant height,pathogenicity,bud number,bud length,pathogenicity,catalpol,rehmaionoside D,leonuride,acteoside were in vestigated respectively.The pathogenicity of rehmannia root and its effects on the synthesis of secondary metabolites of Rehmannia glutinosa were studied.The results showed that the soil fungi isolated from the soil had the effect of causing rot or inhibiting germination,and most fungi had pathogenic or inhibitory growth on the seedlings of Rehmannia glutinosa.The No.4strain of Mucor and Phytophthora 11 have the function of promoting the synthesis of secondary metabolites of Rehmannia glutinosa.A comprehensive analysis of the effects of fungi on Rehmannia glutinosa is made.The comprehensive pathogenic index of fungi such as Penicillium,Fusarium and Trichoderma is high,and the abundance ratio fluctuates with the extension of interval time after planting.The soil samples are stable after 8-10 years.The pathogenicity index of the Rehmannia glutinosa was low and the abundance ratio decreased gradually,and the stability was stable after 8-10 years.3.The soil microecological environment was studied by means of metagenomic molecular sequencing.The results showed that soil microbial diversity and abundance were different in different intervals after planting Rehmannia glutinosa.The highest diversity of soil microorganisms was found in one year,and7134.75 species were detected.Species abundance is second only to soils separated by seven years.Prokaryotic microorganisms were the main microbial communities,accounting for more than 99%.In the 2-3 year after planting Rehmannia glutinosa,the number of soil eukaryotic microbial communities increased significantly,while the number of prokaryotic microbial communities decreased significantly.Subsequently,the total soil microbial abundance fluctuated.After 8-10 years of soil self-healing,the abundance of soil prokaryotic microbes and eukaryotic microbes tended to be stable.After the planting of Rehmannia glutinosa,the beneficial bacteria and the structure of harmful microbial flora changed.With the increase of the interval years after planting the Rehmannia glutinosa,the abundance of Basidiomycota,Burkholderia,Nitrosospira and other bacteria considered as beneficial bacteria increased,and the proportion of harmful microorganisms such as Sphingomonas,Nocardioides and Ascomycota gradually decreased.4.Using genomic analysis of soil functional genes,soil microbes were mainly involved in carbohydrate metabolism,amino acid metabolism,membrane transport,energy metabolism,signal transduction and other metabolic processes.Soil samples showed a first decline and then increased and then decreased in the 1-10 year intervals.The functional genes in 8 and 10 years of soil samples were similar.The relative abundance of functional genes was relatively small.The abundance of thiamine metabolism,bacterial secretory system,ABC transporter and nitrogen metabolism decreased in ten year old soil,and the abundance of purine metabolism,pyrimidine metabolism and two-component system increased.Among them,the metabolism of bacterial secretory system and ABC transporter was a reflection of environmental changes by soil microorganisms.Thiamine metabolism,nitrogen metabolism and other processes are important processes of soil chemical cycling.The decline of their abundance indicates that the soil environment of Rehmannia glutinosa plantation tends to be stable with the increase of interval years.This study found that the evolution process of soil microecology after planting Rehmannia glutinosa is irregular fluctuations.After the interval of 8-10 years,the soil reaches the standard of replantable Rehmannia glutinosa,and the soil microbial structure is relatively stable.Therefore,the imbalance of soil microecological environment may be the key factor to cause continuous cropping obstacle of Rehmannia glutinosa.Artificial adjustment of the micro ecological environment of Rehmannia glutinosa planting soil meets the needs of Rehmannia glutinosa.It may be a green and effective solution to continuous cropping obstacle of Rehmannia glutinosa.