| Pinus massoniana is a pioneering tree species in southern China.It has the advantages of strong adaptability,wide application,fast-growing and high yield.The distribution of Pinus massoniana resources in Guizhou Province is uneven,the productivity of forest land is low,and the area of inefficient forest is increasing.Rhododendron simsii is often associated with Pinus massoniana forest.It is important for maintaining the stability of Pinus massoniana forest and improving forestland productivity.It has high ornamental value and can improve the landscape of the forest in our province.It has great value in garden development and research value.The diversity of fungi in the soil interacts with plant roots to form mycorrhiza,and the interaction between plants and symbiotic fungi can promote and maintain the diversity of both above and below ground.Fungal diversity is an important part of biodiversity,including species diversity,morphological diversity,genetic diversity and functional diversity.Mycorrhizal fungi can increase the survival rate of seedling transplanting and maintain ecological balance,which plays an important role.Its diversity and community structure can contribute to the transformation of barren hills,soil and water conservation,and increase of forest coverage,which is of great significance.Taking the Pinus massoniana-Azalea community in five areas of WuDang(WD),MengGuan(MG),LongLi(LL),XiuWen(XW)and QingZhen(QZ)as the research object,Fungal DNA was extracted from hairy root and Rhizosphere soil,and the rhizosphere layer(5-20 cm)was used to determine soil pH and nutrients,Investigation of environmental factors such as habitat vegetation diversity.The internal transcribed spacer(ITS)region was used as the sequencing study area toanalyze the effects of vegetation diversity and soil physical and chemical factors on the root fungal community through quantitative ecological principle.The ecological function group(ecological guild)was used for taxonomy.The composition of the fungi community and its ecological functional structure were analyzed.The research results are as follows:1.A total of 1315 459 valid sequences were obtained,with the largest count value of 265 bp,reaching 169 083.The main range was 190-290 bp,and the length value was mainly between 2000 and 20000.Among them,618 488 were endophytic bacteria,6 969 91 were rhizosphere fungi,41 231.2 were endophytic fungi and 466.1were rhizosphere fungi.A total of 2695 OTUs were obtained by merging fungal OTU thresholds.The number of OTUs in different flora was WD(1527 OTU)> MG(1163OTU)> LL(1245 OTU)> QZ(721 OTU)> XW(608 OTU),and the total number of OTUs in five flora was 84.The OTU values of fungi measured in different areas are quite different.2.The number of OTU of Rhododendron simsii rhizosphere-specific fungi was792,while that of Rhododendron simsii root-specific fungi was 457 OTU.There were total fungi OTU 1446.All OTUs belong to 11 phyla,32 classes,96 orders,209 families,389 genera and 561 species.QingZhen(QZ)belongs to 10 phylums,25 classes,63 orders,108 families,163 genera and 219 species;XiuWen(XW)belongs to 8 phylums,24 classes,64 orders,115 families,168 genera and 220 species;LongLi(LL)belongs to 9 phylums,26 classes,64 orders,121 families,184 genera and 254 species.WuDang(WD)belongs to 10 phyla,25 classes,63 orders,108 families,163 genera and 219 species;MengGuan(MG)belongs to 9 phyla,27 classes,70 orders,126 families,189 genera and 264 species.3.The dominant flora were Ascomycota(60.1%),Basidiomycota(26.1%)and Zygomycota(5.9%).The dominant classes,orders and families were Agaricomycetes(20.8%),Eurotiomycetes(20.5%),Sordariomycetes(14.4%),Leycoties(8.7%),Archaeormycetes(7.0%).Eurotiales(18.0%),Sebacinales(9.4%),Hypocreales(8.9%),Archaeorhizomycetales(7.0%);Trichocomaceae(18.0%),Archaeorhizomycetaceae(7.0%),Sebacinaceae(6.5%)and so on.The dominant floraof 389 genera of fungi were Penicillium(17.1%),Archaeorhizomyces(7.0%),Sebacina(5.9%),unidentified(4.9%)and Trichoderma(4.3%).4.Mycorrhiza fungi in Rhododendron simsii root are mainly divided into 84 ecological functional groups,such as Undefined Saprotroph(869 OTU),Plant Pathogen(127 OTU),Soil Saprotroph(135 OTU),Ectomycorrhizal(136 OTU),Lichenized(44 OTU),Ericoid Mycorrhizal(33 OTU),Wood Satropproh(26 OTU),Arbusar Mycorrhil(16 OTU),Endophyte(79 OTU)Paten(60 OTU).And a variety of mixed trophic fungi,such as: Fungal Parasite-Undefined Saprotroph(86 OTU);Animal Pathogen-Endophyte-Lichen Parasite-Plant Pathogen-Soil Saprotroph-Wood Saprotroph(23 OTU)and other 73 categories.In addition to rhododendron-like mycorrhizal fungi,Rhododendron roots also have a large number of other types of mycorrhizal fungi and fungi with different ecological functions.5.Rhododendron simsii rhizosphere fungi community structure is highly correlated with Habitat soil TN,pH,AN,AK,AP and Shannon(D)index of vegetation.Different environmental factors affect the distribution of microflora,and there is a selective relationship between microflora and plants.Root endophytic fungi mostly come from the habitat soil.These abundant microflora have complex functional diversity,and the correlation between microflora is coupled,which increases the diversity of Rhododendron root fungi types,as well as the biodiversity and ecological stability of forest ecosystems. |
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