3.3.3 Bioinformatical analyses
In the present study, we identified 398299 sequences from the total dataset, optimized to 391960 sequences. The coverage of OTUs in all soil types was more than 99%. The CK had the largest OTUs richness of AM fungi (Table 6). The highest AM fungal diversity was found in the CK by Shannon index and Simpson index analysis, and gradually decreased with the increase of N addition concentration, and the lowest AM fungal diversity was found in the high N treatment.
The results of the community structural composition showed that the majority of OTUs sequences belonged to Glomus (Fig. 4). The relative abundance of theGlomus increased with N addition and was significantly higher than CK in the HN treatment. In contrast, the relative abundance of Paraglomus reduced by 96.71% in HN treatment compared to CK.
The AM fungal community composition and relative abundance at the species level was shown in Fig.4. The dominant species in the CK wasGlomus -Glo3-VTX00074, Acaulospora -VTX00272 in the LN treatment, Diversispora -unclassified in MN treatment, andGlomus -MO-G5-VTX00219 in HN treatment. It can be seen that the N addition had a significant effect on AM fungal community composition in Korean pine plantation. Glomus -MO-G18-VTX00064 is a special species for the CK and did not appear in other treatments.Glomus -group-B-Glomus -acnaGlo7-VTX00057 was a special and unique specie for the LN treatment. Glomus -MO-G22-VTX00125,Glomus -Wirsel-OTU13-VTX00140 were special and unique species for the MN treatment.