Seasonal Variation Of Rhizosphere And Root Microbial Diversity And Community In Impatiens Hainanensis(Balsaminaceae)on Different Altitude Gradient

Rhizosphere microbial and root endophytic,important components of plant root ecosystems,play important role in the decomposition of soil organic matter,absorption of various nutrients,and growth and development of vegetation.Impatiens hainanensis is the endemic plant in Hainan Island.Impatiens hainanensis has important ornamental and ecological values.It's mainly distributed in karst limestone tropical mountain rain forest.Due to the limitations of the distribution of endemic species and the fragile habitat,the number of wild populations has decreased year by year.Rhizosphere and root microbes play important role in plant growth and development in limestone regions.With seasonal and elevation changes in environmental factors,the distribution and composition of rhizosphere microbial and root endophytic have changed accordingly.To reveal the dynamic changes of Rhizosphere microbial and root endophytic communities in Impatiens hainanensis under different altitudes,the root and rhizosphere soil of Impatiens hainanensis in different seasons,collected at different altitudes of high(1000m),medium(400m)and low(190m)uses the morphological binding molecular detection technology to detect the isolation of cultured fungi and bacteria,and further analysis of microbial community composition and dynamic changes.The results of this study will help understand the local adaptation mechanism of plants in limestone special habitats.Important to study the ecological role of Impatiens hainanensis rhizosphere microorganisms and Impatiens hainanensis conservation.development and utilization.The main findings were as follows:(1)Cultivable microbial species diversityUsing rose benga medium,84 strains rhizosphere fungi of Impatiens hainanensis were isolated and purified,rDNA-ITS sequencing of rhizosphere fungi,primers are ITS-1F and ITS-4,24 species in 14 genera.Dominant species:Trichoderma,Talaromyces,Penicillium,Aspergillus.Using PDA medium,there were 31 strains isolates of Impatiens hainanensis endophytic fungi isolated and cultured,9 species in 7 genera.Dominant species:Fusarium,Trichoderma,Colletotrichum,Corynespora.Using NA medium,60 strains rhizosphere bacteria of Impatiens hainanensis were isolated and purified,16S rDNA sequencing of rhizosphere bacteria,primers are 27f and 1492r,16 species in 9 genera.Dominant species:Bacillus,Burkholderia,Paenibacillus.There were 38 strains endophytic bacteria isolates of Impatiens hainanensis isolated and purified,11 species in 4 genera.Bacillus is a dominant species.(2)Seasonal changes at different altitudesDifferent altitude conditions,The numbers of OTU,diversity index and richness index of rhizosphere and root endophytic fungi in Impatiens hainanensis in dry season were higher than those in wet season.While the number of OTU rhizosphere and root endophytic fungi,diversity index,richness index in Impatiens hainanensis is manifested:High altitude>Low altitude>Middle altitude.Different altitude conditions,The numbers of OTU,diversity index and richness index of rhizosphere and root endophytic bacteria in Impatiens hainanensis in wet season were higher than those in dry season.While the number of OTU rhizosphere and root endophytic bacteria,diversity index,richness index in Impatiens hainanensis is manifested:Low altitude>Middle altitude>High altitude.(3)The driving force of culturable microorganismsThe results of redundancy analysis showed that there was a positive correlation between the rhizosphere fungus and the distribution of fungi in rhizosphere of Impatiens hainanensis in dry season and high altitude gradient.The distribution of fungal communities in rhizosphere and root of Impatiens hainanensis tended to have a trend of high altitude in dry seasons.There was a positive correlation between the bacteria in the rhizosphere and the bacteria in the roots of Impatiens hainanensis under wet season conditions and low altitude gradients.The distribution of bacterial community in rhizosphere and root both tended to be lower in the wet season.The ability of cultivated rhizosphere and root microflora of Impatiens hainanensis to be mainly affected by seasonal changes,the main drivers of rhizosphere and root microbes in Impatiens hainanensis is season,followed by altitude.