宁夏荒漠区生物结皮中细菌群落结构和多样性OA

[Objective]To explore the adaptation of the structure and diversity of bacterial communities in bio-logical soil crusts(BSCs)to environments with varying vegetation coverage ratios in the Ningxia desert region,thereby providing a scientific basis for desertification control and ecological restoration in this area.[Method]BSC samples were collected from plots with different coverage ratios of Calligonum mongolicum to Artemisia scoparia(0∶0,2∶3,1∶1,3∶2,5∶3,7∶3,3∶1,and 7∶1).Single-Molecule Real-Time(SMRT)sequencing technology was em-ployed to sequence the full-length 16S rRNA gene of the bacterial communities,and functional predictions were per-formed using PICRUSt.[Results]A total of 2 311 518 full-length sequences of the bacterial communities were ob-tained from 24 samples,averaging 96 313 sequences per sample.After filtering and denoising,the number of high-quality sequences remained relatively stable in the plot with a C.mongolicum to A.scoparia coverage ratio of 3∶2.Cyanobacteria(50.7%),Proteobacteria(31.3%),and Actinobacteria(14.8%)ranked as the top three phyla in terms of relative abundance within the plots having coverage ratios of 3∶1,1∶1,and 3∶2,constituting the dominant phyla.At the genus level,Wilmottia(14.7%)and Microcoleus(14.7%)were the dominant genera in the plots with 7∶1 and 3∶1 coverage ratios,respectively.Regarding α-diversity,the ACE and Chao1 indices of the bacterial com-munities exhibited consistent variation trends,peaking at 1 258.33±50.55 and 1 189±48.88 in the 1∶1 and 3∶2 coverage ratio plots,respectively.Both the Shannon and Simpson indices reached their maximum values in the 3∶2 coverage ratio plot,at 5.69 and 0.98,respectively.In terms of β-diversity,principal component analysis(PCA)re-vealed that PCA1,PCA2,and PCA3 explained 67.5%,13.7%,and 8.4%of the structural variation in the bacterial communities,respectively.Functional predictions at the phylum level primarily involved macromolecular transport and metabolism,cellular processes,and genetic information processing.[Conclusion]The bacterial communities pos-sess diverse ecological functions,and variations in vegetation coverage ratios significantly affect their community structure and diversity.The bacterial communities thrive optimally in plots with 1∶1 and 3∶2 coverage ratios.These specific environments facilitate the structural maintenance of BSCs and accelerate their formation,thus providing a theoretical basis for further understanding the growth,development,and ecological functions of BSCs in desert re-gions.