Diversity Of Actinomycetes In Rhizosphere Soil And Different Parts Of Broussonetia Papyrifera In Manganese Mine And Antimony Mine Area

Microorganisms are called the second genome of plants,and Broussonetia papyrifera-microbe collaboration is an important mechanism for Broussonetia papyrifera to adapt to poor environments.The current research about Broussonetia papyrifera microbes focuses mainly on rhizosphere soil and endophytic bacteria,and less attention is paid to actinomycetes.Actinomycetes,as an important microbial group,does its community structure and diversity change with environmental impact factors which is consistent with bacteria or have unique rules?Will the biodiversity of actinomycetes in different parts of Broussonetia papyrifera change under the heavy metal stress?In order to solve the scientific problems above,clarify the diversity of actinomycetes in the rhizosphere soil and different parts of Broussonetia papyrifera,explain the mechanism of Broussonetia papyrifera to adapt to the environment and the role of actinomycetes in the resistance to heavy metal stress of Broussonetia papyrifera,the rhizosphere soil,roots,leaves and fruits of Broussonetia papyrifera were collected from Xiangtan Manganese Mine in Hunan,Lengshuijiang Tin Mine in Hunan and Changsha in Hunan,traditional isolation culture and high-throughput sequencing were used to study the diversity of actinomycetes.The sample from Hunan Changsha was used as a control.The results are as follows:(1)Diversity of actinomycetes in the rhizosphere soil of Broussonetia papyrifera in different habitats?Using high-throughput sequencing,actinomycetes were detected in 6 classes,28 orders,58 families,134 genus and 229 species from Hunan Xiangtan Manganese Mine,Hunan Lengshuijiang Tin Mine,and Hunan Changsha Broussonetiapapyrifera rhizosphere soil.The Shannon index,Sobs index and Chao index of rhizosphere soil actinomycetes in Hunan Changsha are the highest,followed by Hunan Xiangtan Manganese Mine,and Hunan Lengshuijiang Tin Mine is the lowest.There is a significant difference between the actinomycetes community in the rhizosphere soil of Broussonetia papyrifera in Hunan Changsha and mining areas(Hunan Xiangtan Manganese Mine and Hunan Lengshuijiang Tin Mine)(P<0.05);However,the roots community of actinomycetes in the soil between the Hunan Xiangtan Manganese Mine and Hunan Lengshuijiang Tin Mine are similar.The order of effect about rhizosphere soil physical and chemical factors on actinomycete community is:Available K>Available P>K>Slow-acting P>Ni;the effect of rhizosphere soil heavy metals content on actinomycete community is:Moisture>Available Cu>Hg>Available Mn>Fe>Nil>Cd.?Using traditional isolation and culture,85 different actinomycetes belonging to 15 genus,were isolated from the soil of Broussonetia papyrifera rhizosphere.Among them,27 strains(6 genus),34 strains(6 genus)and 24 strains(13 genus)of Broussonetia papyrifera were obtained from the rhizosphere soil of Xiangtan Manganese Mine in Hunan,Lengshuijiang Tin Mine in Hunan and Changsha in Hunan,respectively,Streptomyces is the dominant flora.The order of the number of strains with antibacterial effect and the number of antibiotic synthase genes are:Hunan Lengshuijiang Tin Mine>Hunan Changsha>Hunan Xiangtan Manganese Mine.The strain T44T was isolated from the rhizosphere soil of Broussonetia papyrifera in Hunan Changsha,and was identified as a novel species by polyphasic taxonomy.(2)Diversity of endophytic actinomycetes in the roots of Broussonetia papyrifera in different habitats?Using high-throughput sequencing,7 classes,32 orders,59 families,115 genus and 197 species were detected actinomycetes from the roots of Broussonetia papyrifera from different habitats.Shannon index,Chao index and Sobs index of Changsha root endophytic actinomycetes in Hunan Changsha>Lengshuijiang tin mine in Hunan>Hunan Xiangtan Manganese Mine.The endogenous actinomycete community of Broussonetia papyrifera in Hunan Changsha and mining areas(Hunan Xiangtan Manganese Mine and Hunan Lengshuijiang Tin Mine)have significant differences(P<0.05);However,the community composition of actinomycetes in the roots between Hunan Xiangtan Manganese Mine and Hunan Lengshuijiang Tin Mine is similar.The order of effect about heavy metals content on actinomycete community is:Available Cu>Cd>Zn>Hg>Cu>Available Pb.?Thirty-four different actinomycetes belonging to 9 genus were isolated from the roots of Broussonetia papyrifera using traditional isolation and culture.Among them,10 trees(4 genus),19 trees(5 genus),and 5 trees(4 genus)were obtained from the roots in Hunan Xiangtan Manganese Mine,Hunan Lengshuijiang Tin Mine and Hunan Changsha respectively.The dominant flora in the roots of Hunan Xiangtan Manganese Mine and Hunan Lengshuijiang Tin Mine are Streptomyces,while the dominant genus in Hunan Changsha is the Nocardiopsis.The order of the number of strains with antibacterial effect and the number of antibiotic synthase genes are:Hunan Lengshuijiang Tin Mine>Hunan Xiangtan Manganese Mine>Hunan Changsha.The strain Gen01T isolated from the roots of in Hunan Lengshuijiang Tin Mine was identified as a novel species by polyphasic taxonomy.(3)Diversity of endophytic actinomycetes in leaves of Broussonetia papyrifera in different habitats?From different habitats,6 classes,30 orders,55 families,96 genus and 150 species were detected.Hunan Changsha's alpha index(Sobs,Shannon,Chao and Ace index)is the highest,followed by Hunan Xiangtan Manganese Mine,and finally Hunan Lengshuijiang Tin Mine.The community composition of the endophytic actinomycetes in the three different habitats is similar.The order of effect about heavy metals on actinomycete community is:Available Mn>Available Cu>Pb>Cu>Available Zn>Cd>Ni>Available Pb.?Thirty-three different actinomycetes belonging to 8 genus were isolated from Broussonetia papyrifera leaves using traditional isolation and culture.Among them,13 strains(3 genus),8 strains(3 genus)and 12 strains(4 genus)were obtained from the roots of Hunan Xiangtan Manganese Mine,Hunan Lengshuijiang Tin Mine and Hunan Changsha,respectively.The genus Streptomyces is the dominant flora.The order of the number of strains with antibacterial effect and the order of antibiotic synthase genes are:Hunan Xiangtan Manganese Mine>Hunan Changsha>Hunan Lengshuijiang Tin Mine.The strain GY16T isolated from the leaves of Broussonetia papyrifera in Hunan Changsha was identified as a novel species by polyphasic taxonomy.(4)Diversity of endophytic actinomycetes in fruits of Broussonetia papyrifera in different habitats?6 classes,24 orders,53 families,97 genus and 147 species were detected From the Broussonetia papyrifera fruits which are from different habitats.Sobs index and Chao index of actinomycetes in the fruit of Broussonetia papyrifera is:Changsha Hunan>Hunan Xiangtan Manganese Mine>Hunan Lengshuijiang Tin Mine.The community composition of the endophytic actinomycetes in the fruit of Broussonetia papyrifera from three different habitats was similar.The order of influence about heavy metals on the actinomycete community is:Cd>Available Cu>Available Pb>Cu>Available Mn>Pb>Ni>Available Zn.?Using traditional isolation and culture,26 different actinomycetes belonging to 6 genus were isolated from the fruits of Broussonetia papyrifera.Among them,14 strains(3 genus),5 strains(2 genus)and 7 strains(3 genus)were obtained from the roots of Hunan Xiangtan Manganese Mine,Hunan Lengshuijiang Tin Mine,and Hunan Changsha,respectively.The genus is the dominant flora.The number of strains with antibacterial effect is Hunan Xiangtan Manganese Mine(12 strains),followed by Hunan Lengshuijiang Tin Mine(5 strains),and finally Hunan Changsha(4 strains).The order of the number of strains containing antibiotic synthase genes(PKS,PKS? and NRPS)is:Hunan Xiangtan Manganese Mine(8 strains)>Hunan Changsha and Hunan Lengshuijiang Tin Mine(3 strains).In summary,this research systematically studied the distribution of actinomycetes in the rhizosphere soil,roots,leaves and fruits of Broussonetia papyrifera in three different habitats,and the impact of environmental factors on them.It provides a basis for the planting and promotion of Broussonetia papyrifera,and at the same time,it provides basis and abundant materials for the research of plant rhizosphere and endophytic actinomycetes,and for the development and utilization of microbial resources.