The Effect Of Five Years Continuous Cropping Of Coptis Chinensis Franch On Soil Microbial Communities

Coptis chinensis Franch is one of the most important medicinal plants in China.It grows at an altitude of about 2,000 m,cold,wet and shade environment,avoid high temperature and strong light point.C.chinensis mostly used for clear heat and dry dampness,detoxification,diarrhoea,insomnia,hot eyes,toothache and diabetes.C.chinensis mainly distributed in Hubei,Chongqing,Sichuan and Yunnan provinces in China.Continuous cropping of plants is often the cause of yield reduction and many diseases in plants.Furthermore,to cause microbial diversity and to change the composition of bacterial and fungal populations in the rhizosphere,it effects on soil health,quality and prevented sustainable production.Auto toxicity of root exudates also has been considered as one of the main reasons for continuous cultivation obstacle of plants especially in medicinal plants.In the current study,we provide detailed information regarding the diversity and composition of the rhizospheric bacterial and fungal communities of the C.chinensis plants in continuously cropped fields and fallow fields in two seasons?i.e.,winter and summers?using next-generation sequencing.The results of the study are as follows:1. With the increasing years of C.chinensis cultivation,the total content of nitrogen,phosphorus,and organic matter significantly increased in both winter and summer seasons.The soil organic matter varied from 11.16 to 36.04 g kg^-1 in winter and from 8.35 to 33.90 g kg^-1 in summer.The organic matter contents were significantly higher in five-year cultivated filed?Cy S5?and lower in the one-year cultivated field?Cy S1?.The soil total nitrogen value varied from 0.99 to 3.27 g kg^-1 in winter and from1.02 to 2.68 g kg^-1 in summer,among which the five-year?Cy S5?soil had the highest content in winter and summer(3.27,2.68 g kg^-1)and the one-year?Cy S1?fields had the lowest content in both winter and summer.The total soil potassium value was highest in the five-year?Cy S5?fields in both winter and summer(4.18,4.18 g kg^-1respectively)and had the lowest value in the fallow fields?NCS?(1.17,1.47 g kg^-1).Furthermore,the p H was slightly acidic and varied from 4.49 to 5.84 in winter and 5.59to 6.48 in summer,the highest value in one-year?Cy S1?and the lowest value in five years?Cy S5?in two seasons.2. Alpha diversity indices,i.e.,Chao,Shannon,Observed OTUs,and Phylogenetic diversity?Pd?,were used.The alpha diversity in fungal community was considerably higher in the treatment Cy S1 as compared to the subsequent treatments,i.e.,Cy S3 and Cy S5.The variety in the fallow fields was lowest as compared to the cultivated fields.The observed OTUs were significantly higher in the Cy S1.Coverage from all samples was above 97%,representing that sequencing reads were sufficient for this analysis.In bacterial community Observed species,phylogenetic diversity,Chao1,and Shannon index showed a significant?p<0.05?higher richness and diversity under a one-year field across two time-series soil sampling.Simpson index showed an opposite tendency with the Shannon index in winter and summer soil sampling.3. Principle coordinate analysis?PCo A?based on Uni Frac distances,i.e.,Unweighted and weighted revealed the rhizospheric fungal communities of the C.chinensis in the different years clustered separately in the summer season of the cropping years however the rhizospheric fungal communities of the third year and fifth years were grouped in the winter season.Differentiated the bacterial communities in soils used for cultivating C.chinensis three-years?Cy S3?and five-years?Cy S5?cultivated C.chinensis field were separated by PC1 and cultivated C.chinensis field?Cy S1,Cy S3,Cy S5?were separated from the fallow field by PC2.4. Venn diagrams show 17,3,5,and 2 unique species were present in the one-year?Cy S1?,three-year?Cy S3?,five-year?Cy S5?,and fallow?NCS?fields,respectively,while 20,7,10,and 21 unique species were present in the summer sampling time,respectively fungal community.in the winter 264,13,23 and 47 particular species were identified in the one-year?Cy S1?,three-year?Cy S3?,five-year?Cy S5?and fallow?NCS?field respectively,in the summer 225,32,19 and 113 unique species were identified,in the bacterial community.5. The classified OTUs from all soil samples were primarily affiliated in the eight fungal phyla.Ascomycota?55.20%of all sequence reads?,Basidiomycota?25.94%?,unclassified fungi phyla?3.46%?,and Glomeromycota?1.68%?were the top four fungal phyla in winter.Whereas,Ascomycota?49.98%of all sequence reads?,Mucoromycota?21.48%?,Basidiomycota?10.16%?,and unclassified Fungi?7.99%?were the four most dominated fungal phyla in summer.For bacterial taxa in winter soil sampling,the top five abundant phyla in all samples were Proteobacteria,Actinobacteria,Chloroflexi,Acidobacteria and Bacteroidetes with average relative abundances of 30.33%,22.41%,14.38%,13.70%,and 4.34%respectively.While in summer,Proteobacteria,Acidobacteria,Chloroflexi,Actinobacteria,and Patescibacteria,with average relative abundances of 37.54%,24.91%,10.74%,6.96%,and 4.77%respectively.6. FUNGuild classified three main trophic modes?Pathotroph,Saprotroph,and Symbiotroph?,including eight functional guilds in our samples.Overall,in trophic mode,Saprotroph was the dominant trophic type in winter and summer,except in Cy S3in winter that was dominated by Symbioroph?27.41%?.Besides,phototroph was the dominant fungal trophic mode in Cy S1?13.60%?in summer and NCS?21.27%?in winter.The 16S r RNA gene profiling information PICRUSt to predict the abundance of C and N functional genes found a significant difference between the soil samples from cultivated?Cy S1,Cy S3,and Cy S5?and fallow?NCS?fields in two seasons?winter and summer?.The abundance of the C and N functional genes found significant differences and higher abundance in the fallow field in summer.In contrast,there was a lower abundance in winter.7. Redundancy analysis?RDA?of the dominant phyla data and soilphysiochemical properties revealed variations in fungal community structure in the soil samples.The first two RDA components?RDA1 and RDA2?explain 20.55%and 6.88%of the total variance,respectively,in winter and 44.57%,1.93%?RDA1 and RDA2?,in summer in the fungal community.RDA axis1 explained RDA axis2 explained 40.79%of the variation and 7.75%in winter and 47.36%and 12.76%by RDA axis1and RDA axis2 respectively,in summer in the bacterial community.