Study Of The Effects Of Planting Years On The Quality And Soil Microbial Communities Of Paris Polyphylla Var. Yunnanensis

Paris polyphylla var.yunnanensis is a rare and endangered medicinal plant with significant market demand and slow growth.Artificial cultivation is one of the effective ways to alleviate its resources.However,with the increase in cultivation years root rot and other diseases increase year by year and continuous cropping obstacles become more and more serious,which has become the bottleneck of the development of the P.polyphylla var.yunnanensis planting industry.However,the reason and mechanism of continuous cropping and the change law of active components in the process are not apparent.Clarifying the change law of soil microorganisms and functional elements in the constant cropping process of P.polyphylla var.yunnanensis is of great significance to solving sustainable development.This study took P.polyphylla var.yunnanensis,and its rhizosphere soil was planted continuously for 2,3,5,and6 years under the same cultivation conditions as the research object.UPLC-MS,ICP-OES,and high-throughput sequencing technology were used to study the variation law of its active components and the expression difference of critical enzymes for synthesis,as well as the physical and chemical properties of Rhizosphere Soil and the composition and diversity of soil microbial community,To explain the quality formation and planting obstacle formation mechanism of P.polyphylla var.yunnanensis from multiple angles,and provide scientific reference for the scientific cultivation of it.The results are as follows:1)The six active components in P.polyphylla var.yunnanensis showed a fluctuating trend among different planting years,which had no significant correlation with planting years.The PCA,PLS-DA,and HCA analysis results showed the samples with different planting years could be significantly classified,and the sample point of 6-year-old P.polyphylla var.yunnanensis is far from 2-year-old,3-year-old,and 5-year-old samples.2)With the increase of planting years,the nutrients in the rhizosphere soil of P.polyphylla var.yunnanensis showed a fluctuating trend,the p H decreased,and the soil showed an acidification trend.After six years of planting,the contents of trace elements in the soil of P.polyphylla var.yunnanensis were significantly different from those of 2,3,and 5 years old.The contents of B,Mn,Zn,and Fe decreased,and Cu increased.3)With the increase of planting years,the diversity of bacteria and fungi in the rhizosphere soil of P.polyphylla var.yunnanensis decreased,the richness of bacteria decreased,and the richness of fungi increased.Among them,the abundance of Actinobacteriota,Chloroflexi,Gemmatimonadota,Latescibacterota,and Methylmirabilota decreased,and the relative abundance of Arthropoda,Ciliophora,and Platyhelminthes increased.The relative abundance of Streptophyta decreased after planting P.polyphylla var.yunnanensis,but increased with the planting year limit.LEf Se analysis showed the most significant difference in the relative abundance of bacteria Nitrosomonadaceae,Actinobacteria,Acidobacteria,Chloroflexi,and fungi Hemiptera Arthropoda,Oomycetes,and Polypodiales.4)The comparison of rhizosphere soil between diseased and healthy P.polyphylla var.yunnanensis showed that the soil nutrients,p H,and other trace elements in diseased P.polyphylla var.yunnanensis were lower than those in healthy P.polyphylla var.yunnanensis except Cu.The microbial abundance of it changed after the disease.Among them,bacteria and fungi such as Actinobacteria,Chlorophyta,Cnidaria,and Streptophyta were more in the diseased soil than in healthy soil.The results of lefse analysis showed the abundance of bacteria Porticoccaceae and Elsterales,fungi Apiales and Trematoda in diseased and healthy P.polyphylla var.yunnanensis soil were the most different.(5)The number of DEGs is different among P.polyphylla var.yunnanensis with different planting years.The gene function annotation focuses on biological process,cell component,and molecular function process,mainly cellular process,cell part,and catalytic activity.The number of steroidal saponin biosynthesis pathways enriched by DEGs was 40,11,41,55,86,and 40,respectively in P2 vs P3,P2 vs P5,P2 vs P6,P3 vs P5,P3 vs P6,and P5 vs P6.In the biosynthetic pathway of steroidal saponins,there are many different genes of STM1 and SMO2.(6)The results of correlation analysis showed polyphyllin I was significantly correlated with Zn,Fe,available phosphorus,B,Mn,and Cu.Polyphyllin?was significantly associated with B and Fe,polyphyllin?was correlated considerably with Zn and extremely significantly correlated with Fe,and polyphyllin?was significantly correlated with polyphyllin?was markedly correlated with nitrate nitrogen,p H,and B.Gracillin was significantly associated with B and Fe.Both bacteria and fungi have a significant or highly significant correlation with one or more steroidal saponins.Gemmatimonadota,Latescibacterota,and Nitrospirota were significantly correlated with polyphyllin?.Chloroflexi and Latescibacterota were connected considerably with polyphyllin?.Latescibacterota was markedly correlated with polyphyllin?,polyphyllin?,and gracillin.There was no significant correlation between dominant phylum saponins in fungi.Soil factors were significantly associated with microbial community.SOM had the most significant impact on the bacterial community in soils with different planting years,and Mn had the most significant effect on the fungal community.In the diseased and healthy soil of P.polyphylla var.yunnanensis NO₃^-had the most significant impact on the bacterial community,and Zn had the most significant impact on the fungal community.Conclusion(1)Planting years affects the accumulation of soil physical and chemical properties,microbial community structure,and effective component content of P.polyphylla var.yunnanensis.Seedling raising and transplanting is an effective measure to overcome continuous cropping obstacles.(2)In P.polyphylla var.yunnanensis cultivation,we should prevent soil acidification,supplement elements such as B,Mn,Zn,and Fe,and increase microbial fertilizer simultaneously.(3)It is speculated that Dongia,Vibrionimonas,and Porticoccaceae in bacteria may be pathogenic bacteria,Epilachna and Trematoda in fungi may be pathogenic Elsterales in bacteria,and Apiales in fungi may be beneficial bacteria.(4)In different planting years,the sum of polyphyllin I,polyphyllin II and polyphyllin VII is the highest in 5-year-old P.polyphylla var.yunnanensis,SMT1 and SMO2 may be the critical enzymes in the synthesis of steroidal saponins from it.