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Diversity And Change Of Bacteria Community In The Planting Soil Of Panax Notoginseng

Posted on:2019-01-13Degree:MasterType:Thesis
Country:ChinaCandidate:Q SunFull Text:PDF
GTID:2370330548472850Subject:Bio-engineering
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Sanqi(Panax notoginseng)a perennial traditional Chinese medicine with huge pharmaceutical and economical values.Due to the special habits,P.notoginseng is vulnerable to diseases caused by different causal agents.The unbalanced microbial system in plantation soil caused by no-tillage for cultivation years and applicating chemical pesticides and ferilizers is one main factor for the frequent occurrence of diseases.In the microbiome of cultivation soil,bacteria,as an important group,play a key role in health/pathogenisis of P.notoginseng.Therefore,it is necessary and helpful to investigate in-depth the bacterial communities and their changes in the soil during the cultivation life in learning about the occurrence and control the notoginseng diseases caused by pathogenic bacteria.In this thesis,the next sequence technique MiSeq was employed to investigate the bacterial communities in the cultivation soils collected from Changhu,Shilin,Kunming,and Hongxi,Mile,Honghe.The bacteria reads from soil collected from Shilin were assigned to 40 phylums,104 classes,204 orders,389 families,and 746 genus(including unclassified units),while those from soil of Hongxi were assigned to 39 phylums,102 classes,198 orders,371 families,and 716 genus(including unclassified units).The diversity and relative abundance of bacteria in soil from Shilin are higher than that in soil from Hongxi at the level of phylum and order.At the phylum level,the dominant communities and proportions did not presented difference in the notoginseng cultivation soils of two plantations.At the order level,the bacterial communities differed largely in the soils of two collection sites,although Rhizobiales,Gemmatimonadales,Acidoberieles,Xanthomonad and Burkholderiales were the common dominant orders of the two places.The abundances of Xanthomonadeles,Rhizobiales,Acidobacteriales,Burkholderiales in the soil collected from Hongxi were significantly higher than that in the soil collected from Shilin.while the relative abundances of the Gemmatimonadales,Sphingomonadales,Micrococcales,and Sphingobacteriales in the soil collected from Shilin were significantly higher than that in the soil collected from Hongxi.The bacterial diversity presented a decreasing trend during the whole cultivation period in the notoginseng soil of Shilin,while it changed without significance till May in the second growth year after transplanting and the index of bacterial diversity increased slightly during August to Novermber in the secondary year before haverst in the soil of Hongxi.The plate confrontation method and the agar-diffusion method were employed to screen the antimicrobial active strains from the bacterial isolates obtained from the soils collected from the two plantaion sites.Totally,212 bacterial strains presented activities against the main pathogenic fungi of notoginseng,among them,86 against one pathogenic fungus,95 against two pathogens and 31(14.7%)were active on all tested three target fungi.Isolates PH10001?PH10006 presented the highest activities to the main pathogens Fusarium oxysporum?F.solani?F.flocciferum,inferring that these strains could be potential in biotrolling the notoginseng's disease.In these active isolates,most were assigned to Bacillus and Pseudomonas genera,other small groups belonged to the genera of Leifsonia,Micrococcus,Rhodococcus,Terrabacter,Kitasatospora,Dietzia,Sphingobacterium,Chitinophaga,etc.Six frequently-used pesticides(fungicides)in notoginseng field management were selected to investigate the effects on the active bacterial isolates.Triam could inhibit the growth of isolates PH10001?PH10002?PH10003?PH10012?PH10032 at concentrations from 10 ?g/m L to 400 ?g/m L.The results indicated that some fungicides could affect soil bacterial growth,although they are used to treat the pathogenic fungi.
Keywords/Search Tags:Panax notoginseng, Cultivation soil, Soil-borne bacteria, Community structure, Fungicide
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