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Under the influence of global climate change and human activities, forest expansion has become increasingly significant in shaping ecosystems. However, its effects on soil microbial communities remain poorly understood. This study investigates the impacts of forest expansion on soil bacteria, fungi, and protists within mountaintop forest ecosystems. Soil samples were collected from three forest habitats: non-forest expansion mountaintops (NFE-Top), forest expansion mountaintops (FE-Top) and mountain bottoms (FE-Bottom). This study revealed that forest expansion promoted microbial sharing between mountaintop and bottom forests, resulting in greater community similarity between FE-Top and FE-Bottom compared to NFE-Top and FE-Bottom. Notably, forest expansion significantly reduced microbial diversity and altered community composition, particularly within bacterial communities. Microbial network analyses indicated that forest expansion mountaintops were more stable, with higher robustness, and lower vulnerability than non-forest expansion mountaintops. Stochastic assembly processes dominated the microbial communities across all forest habitats, with their relative importance increasing after forest expansion. Furthermore, forest expansion decreased the community-level habitat niche breadth of microbial communities. Distinct environmental factors were the primary indicators of microbial community dissimilarities across different habitats, with TP, pH, and moisture acting as key indicators of these differences in NFE-Top, FE-Top, and FE-Bottom, respectively. These findings highlight the important role of forest expansion in shaping microbial community dynamics and emphasize the potential of microbial communities as indicators of ecosystem changes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier Inc. All rights reserved.)

Dryland covers >35 % of the terrestrial surface and the global extent of dryland increases due to the forecasted increase in aridity driven by climate change. Due to the climate change-driven aridity ecosystems, deserts provide one of the most hostile environments for microbial life and survival. Therefore, a detailed study was carried out to explore the deserts with different aridity levels (exposed to severe climate change) influence on microbial (bacteria, fungi, and protist) diversity patterns, assembly processes, and co-occurrence. The results revealed that the aridity (semi-arid, arid, and hyper-arid) patterns caused distinct changes in environmental heterogeneity in desert ecosystems. Similarly, microbial diversities were also reduced with increasing the aridity pattern, and it was found that environmental heterogeneity is highly involved in affecting microbial diversities under different ecological niches. Interestingly, it was found that certain microbes, including bacterial (Firmicutes), fungal (Sordariomycetes), and protistan (Ciliophora) abundance increased with increasing aridity levels, indicating that these microbes might possess the capability to tolerate the environmental stress conditions. Moreover, microbial community turnover analysis revealed that bacterial diversities followed homogenous selection, whereas fungi and protists were mostly driven by the dispersal limitation pattern. Co-occurrence network analysis showed that hyper-arid and arid conditions tightened the bacterial and fungal communities and had more positive associations compared to protistan. In conclusion, multiple lines of evidence were provided to shed light on the habitat specialization impact on microbial (bacteria, fungi, and protists) communities and composition under different desert ecosystems., Competing Interests: Declaration of competing interest All co-authors have seen and agree with the contents of the manuscript. We declare that we have no known competing financial and personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Streptomycetes have been, for over 70 years, one of the most abundant sources for the discovery of new antibiotics and clinic drugs. However, in recent decades, it has been more and more difficult to obtain new phylotypes of the genus Streptomyces by using conventional samples and culture strategies. In this study, we combined culture-dependent and culture-independent approaches to better explore the Streptomyces communities in desert sandy soils. Moreover, two different culture strategies termed Conventional Culture Procedure (CCP) and Streptomycetes Culture Procedure (SCP) were employed to evaluate the isolation efficiency of Streptomyces spp. with different intensities of selectivity. The 16S rRNA gene amplicon analysis revealed a very low abundance (0.04-0.37%, average 0.22%) of Streptomyces in all the desert samples, conversely the percentage of Streptomyces spp. obtained by the culture-dependent method was very high (5.20-39.57%, average 27.76%), especially in the rhizospheric sand soils (38.40-39.57%, average 38.99%). Meanwhile, a total of 1589 pure cultures were isolated successfully, dominated by Streptomyces (29.52%), Microvirga (8.06%) and Bacillus (7.68%). In addition, 400 potential new species were obtained, 48 of which belonged to the genus Streptomyces. More importantly, our study demonstrated the SCP strategy which had highly selectivity could greatly expand the number and phylotypes of Streptomyces spp. by almost 4-fold than CCP strategy. These results provide insights on the diversity investigation of desert Streptomyces, and it could be reference for researchers to bring more novel actinobacteria strains from the environment into culture., Competing Interests: Declaration of competing interest All co-authors have seen and agree with the contents of the manuscript. We declare that we have no known competing financial and personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)