The Study On The Genetic Diversity Of Am Fungi In Roots And Rhizosphere Soil Of Eight Allium Plants In Inner Mongolica

Arbuscular mycorrhizal fungi(AMF)is an important microorganisms which are widespread and formed arbuscular mycorrhizas(AM)with plant roots in terrestrial ecosystem.The plants of Allium genus with Arum-typt AM are the common species in grassland and desert vegetation of Inner Mongolia.The wild plants of Allium genus,including A.anisopodium,A.bidentatum,A.condensatum,A.mongolicum,A.ramosum,A.senescens,A.tenuissimum and A.yuchuanii,were choosed as the research objects in this paper.The genetic diversity of AM fungi of these plants were studied and based on 18SrDNA gene and ITS sequencing.Endophytic bacteria of the roots were studied by sequencing 16SrDNA.The morphological species diversity of AM fungi also be examined in the rhizosphere soil of the plants roots,and also including soil physical and chemical properties,the members of microbial community,and soil enzymes activity-Furthermore,the corelation bewteen the AM fungi diversity and the soil environmental factors were analyzed,in order to indicate the symbiotic and distribution mechanism of AM fungi with Allium genus plants.The main findings as below:1.All of the Allium species form the Arum-type arbuscular mycorrhiza.The hyphae,arbuscule and vesicule have been observed in the all of plants roots.Hyphaes was very common,but the percentages of arbuscule and vesicule were different with depend on plant species and their growing environments,but mycorrhizal colonization rate were varied from high to low among the plant species,A.yuchuanii>A.tenuissimum>A.condensatum,A.ramosum,A.senescens>A.anisopodium>A.bidentatum>A.mongolicum successively.2.18SrDNA sequencing phylogenetic analysis to the root of a 8 wild Allium plants,15 sequences were all clustered in Glomeraceae in phylogenetic analysis,a part of sequences had high similarity with sequences of genus Ambispora,Claroideoglomus and Glomus.The five AMF species have been identified,which are Ambispora leptoticha,A.sp,Claroideoglomus claroideum,C.etunicatum and Glomus sp.Base on the ITS sequencing,the sequences from 8 Allium plants were clustered in Glomeraceae had high similarity with sequences of genus Claroideoglomus,Diversispora,Glomus,Rhizophagus,Septoglomus Paraglomerales(Paraglomus)and Glomerales unidentified.According to the sequences analysis,the symbiotic AM fungi in the root of Allium were obviously different in different plots with different species.3.The endophytic bacteria species of the 8 Allium genus plants were identified in based on 16SrDNA sequencing.There are 7 species bacteria,among them are Bacillus amyloliquefaciens,B.aryabhattai,B.axarguiensis,and B.megaterium,belong to Bacillus genus.Others are Enterobacter asburiae,E.cancerogenus,and Pantoea agglomerans.4.6 genera and 12 morphological species of AMF were isolated from the rhizosphere soil of 8 Allium genus plants.The 3 species belong to Acaulospora,2 species belong to Claroideoglomus,1 species belong to Funneliformis,3 belong to Glomus,1 species belong to Septoglomus,1 species belong to Scutellospora,and one unidentified species.Sept.constrictum was the dominant species in the rhizosphere soil of allAllium species.C.claroideum and A.sp1 are the rare species in the rhizosphere soil of A.condensatum,A.tenuissimum,and A.ramosum in s1 sample.Scut.calospora was rare species in the A.condensatum,A.tenuissimum,A.ramosum,A.senescens,A.bidentatum in s3 sample sites.The AMF species richness,spore density and Shannon Wiener index are varied successively from 4 to 7,24 to 55,and 1.85 to 2.24 in per 20 grams of soil.It was showed that spore density is positive correlation with spore richness(SR)and Shannon Wiener index(H)but not significantly.Spore richness is positive correlation with H,but not significantly.5.Microbial populations which can cultivate was 40?833×104/g soil of bacteria,43?385×104/g soil of actinomycetes,and 14?80×104/g soil of fungi in rhizosphere soil of 8 Allium plants.Physical and chemical properties of plant rhizosphere soil had been analyzed.Ammonium nitrogen(AN),available phosphorus(RP)and total carbon(TC)are about 62.5?283.33mg.kg-1,0.47?7.67mg.kg-1 and 0.53?2.81mg.kg-1 respectively.Total nitrogen(TN)and Total phosphorus(TP)are about 0.03?0.29mg.g-1 and 0.02-0.1mg.g-1.Available potassium(AK)is about 0.09?6.86g.kg-1.Soil pH value is about 6.7?8.63.The soil phosphatase ativity is about 0.01?0.15 mg phenol/gd-1,and sucrase(SUC)is 4.0?84.37mg.g-1,and urease(UAO)is about 93.56?854.37U.g-1.6.The correlation of AM fungi and soil factors were analyzed with CCA.There are the correlationship between spore density(SD),spore richness(SR),Shannon Wiener index with the soil factors.SD had positive correlation with TP significantly(P=0.019).Shannon Wiener index had positive correlation with AK(P=0.033),RP(P=0.016)and the number of bacteria(P=0.043)significantly.H is negative correlation with alkaline phosphatase(P=0.025)significantly.The results of principal component analysis with the ditribution of AM fungi and main soil factors were as follows.TP had positive correlation with Scutellospora calospora(r=0.293,P=0.411).RP had positive correlation with Claroideoglomus etunicatum(r=0.099,P=0.784).AK had positive correlation with Acaulospora sp2(r=0.055,P=0.88).ALP had positive correlation with Scutellospora calospora(r=0.551,P=0.098).The number of bacteria had negtive correlation with Acaulospora laevis(r=-0.179,P=0.622).