| Mycorrhiza is a common ecological phenomenon in terrestrial ecosystems.Ectomycorrhiza play an important role in the establishment and maintenance of forest ecosystems by establishing a symbiotic relationship between fungi and host plants in the long evolutionary process.In the mycorrhizal system,in addition to the exchange of photosynthates,water and minerals between plants and mycorrhizal fungi,other fungi and bacteria in the this system also participate in the matter metabolism and energy cycle,which form the mycorrhizal microecology.This study uses the concept of mycorrhizal microecology,by the methods of high-throughput sequencing and fungal biology,the bacterial community structure of Pinus koraiensis mycorrhizal system were analysised,and obtained the culturable microbial groups in Pinus koraiensis mycorrhizal system by isolation,purification and culture.The relationships between the microorganisms in the root system of Pinus koraiensis were determined by the culture of Buchwaldoboletus lignicola.The interrelationship between the microorganisms was investigated by studying the growth-promoting effect of Pinus koraiensis mycorrhizal bacteria on Arabidopsis thaliana,and the following results were obtained.(1)The diversity and species composition of bacterial microbial community were different in different age of forest land.The Chao1 index for the CS1 sample site was 1250.35,the Ace index was 1620.12,the Shannon index was 3.28 and the Simpson index was 0.15.The Chao1 index for the CS2 sample site was 1078.89,the Ace index was 1334.81,the Shannon index was 3.32 and the Simpson index was 0.13.The Chao1 index for the CS3 sample site was 883.35,the Ace index was 1161.30,the Shannon index was 2.96 and the Simpson index was 0.14.The Chao1 index for the CS4 sample site was 1082.00,the Ace index was 1224.38,the Shannon index was3.27 and the Simpson index was 0.09.Dominant genus in the mycorrhizal system of the CS1(c.60-year-old pure Pinus koraiensis plantation)sample site: Pseudomonas,Rahnella,Enterobacter,Acinetobacter,Rhizobium,Burkholderia,Streptomyces,Serratia;Dominant genus in the mycorrhizal system of the CS2(c.60-year-old pure Pinus koraiensis plantation)sample site: Pseudomonas,Enterobacter,Rahnella,Acinetobacter,Burkholderia,Bradyrhizobium,Rhizobium,Arthrobacter;Dominant genus in mycorrhizal systems in sample plots of CS3(5-year-old Pinus koraiensis nursery): Pseudomonas,Enterobacter,Rhizobium,Flavobacterium,Burkholderia,Rahnella,Janthinobacterium;Dominant genus in the mycorrhizal system of the CS4(ca.150 years old mixed primary Pinus koraiensis forest)sample site: Pseudomonas,Rahnella,Enterobacter,Burkholderia,Rhizobium,Bradyrhizobium.Soil p H,effective nitrogen and effective potassium had an effects on the abundance of bacterial genus in the roots system.Correlation analysis was conducted between the bacteria in the roots system of Pinus koraiensis fungus and the dominant ectomycorrhizal fungi inside the roots system of Pinus koraiensis fungus,and it was found that there was a certain linear relationship between the bacteria in the roots system of Pinus koraiensis fungus and the dominant ectomycorrhizal fungi inside the roots system.Lactarius showed a positive correlation with Erwinia,Russula was positively correlated with DA101 and Candidatus?Solibacter,Sebacina was positively correlated with Pedomicrobium and Arthrobacter,Suillus was positively correlated with Nitrospira and negatively correlated with Arthrobacter,Tomentella was positively correlated with Serratia and negatively correlated with Enterobacter,Tylospora was positively correlated with Burkholderia and negatively correlated with Candidatus?Solibacter.(2)The microorganism in the mycorrhiza of Pinus koraiensiswere isolated and cultured according to the types of mycorrhizae.The mycorrhiza of Pinus koraiensis can be divided into five general types: absent,dichotomous,dichotomous-like,pinnate and tubercle-like.Isolation and culture of in roots microorganisms from the type of Pinus koraiensis mycorrhiza,148 samples of fungal strains belonging to 9genus and 125 species were obtained.Of these,37 samples of fungal strains were obtained from dichotomous-like,45 samples of fungal strains from dichotomous,35 samples of fungal strains from tubercle-like,20 samples of fungal strains from absent and 11 samples of fungal strains from pinnate.65 bacterial strains were successfully isolated and purified,belonging to 21 species of 7 genus.13 samples of bacterial strains were obtained from dichotomous-like,17 from dichotomous,13 from tubercle-like,7 from absent and 15 from pinnate.(3)The fungi and bacteria in the mycorrhizal system of Pinus koraiensis promoted or inhibited the mycelial growth of Buchwaldobolola lignicola.Standoff culture experiments with Buchwaldoboletus lignicola on the obtained microorganisms within the mycorrhizal roots of Pinus koraiensis showed that: A total of nine bacterial species promoted Buchwaldoboletus lignicola.The mycelial growth of Buchwaldoboletus lignicola showed significantly accelerated growth after inoculation with the bacterial strains Bacillus wiedmannii and Bacillus thuringiensis,inoculation with bacterial strains Bacillus toyonensis,Bacillus cereus,Bacillus safensis,Bacillus Paralicheniformis,Bacillus sp1,Bacillus aryabhattai,and Bacillus pakistanensis showed accelerated growth.After Lysinibacillus pakistanensis,the mycelial growth of Buchwaldoboletus lignicola showed accelerated growth.A total of four fungal species promoted Buchwaldoboletus lignicola.The mycelial growth of Buchwaldoboletus lignicola showed significantly accelerated growth after inoculation with the fungal strains Ilyonecitra robusta and Humicola fuscoatra.Mycelial growth of Buchwaldoboletus lignicola showed accelerated growth after inoculation with the fungal strains Mortierella sp1,Ilyonecitra cyclaminicola.(4)Bacteria in the mycorrhizal system of Pinus koraiensis can promote the growth of Arabidopsis thaliana.The results of growth promotion experiments used standoff experimental methods with the obtained Pinus koraiensis mycorrhizal endophytes against Arabidopsis thaliana showed that: Bacterial strains Bacillus proteolyticus,Bacillus paralicheniformis,Enterobacter hormaechei,Bacillus toyonensis,Enterobacter sp2,Bacillus safensis,Paenibacillus sp.,Bacillus subtilis,Bacillus aryabhattai,Enterobacter ludwigii,Serratia marcescens,Lysinibacillus pakistanensis,and Bacillus cereus had rooting-promoting effects on Arabidopsis thaliana.Bacterial strains Lysinibacillus pakistanensis,Bacillus proteolyticus,Bacillus aryabhattai,Bacillus cereus,Paenibacillus sp.marcescens,Enterobacter ludwigii,Bacillus subtilis,Enterobacter sp2,Bacillus toyonensis,Bacillus safensis,Enterobacter hormaechei and Bacillus paralicheniformis contributed to the length change of Arabidopsisthaliana roots.Bacterial strains Bacillus toyonensis,Bacillus thuringiensis,Paenibacillus sp.,Bacillus aryabhattai,Enterobacter ludwigii,Serratia marcescens Enterobacter sp1,and Bacillus sp2 can promote leaf colour deepening in Arabidopsisthaliana.Bacterial strains Bacillus paralicheniformis,Lysinibacillus pakistanensis,Serratia marcescens,Enterobacter sp1,Bacillus proteolyticus,Bacillus toyonensis,Lelliottia amnigena,Bacillus thuringiensis,Enterobacter ludwigii,Bacillus aryabhattai,Bacillus cereus,Paenibacillus sp..and Enterobacter cloacae had a facilitative effect on weight gain in Arabidopsis thaliana.Bacterial strains Bacillusparalicheniformis,Lysinibacillus pakistanensis,Serratia marcescens,Enterobacter sp1,Bacillus thuringiensis,Enterobacter ludwigii,Bacillus aryabhattai,Bacillus cereus,Enterobacter cloacae and Bacillus safensis promote the growth of Arabidopsis thaliana.In summary,bacteria in the mycorrhizal system had a significant growth-promoting effect on mycorrhizal fungi and Arabidopsis thaliana,while mycorrhizal endophytic fungi showed mainly antagonistic effects. |
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