The sulfur (S) cycle is one of the geochemical element cycles in which microorganisms play a key driving role. The microbial function of soil S cycling in response to desert degradation, however, remains largely unknown. We used metagenomics to analyze the characteristics of microbial communities and their functional genes involved in the S cycles under natural water gradients with three typical halophytes shrubs in the Ebinur Lake basin Desert, China. Our results showed that the rhizosphere effect, water gradient, and halophyte type played a major role in shaping the S cycle. On the whole, in the rhizosphere type and low water environment, the functional genes involved in the S cycle had high abundance, and the sulfur oxidizing protein (SOX) system in Alhagi sparsifolia had a high expression level. In the S cycle network structure, as the soil water content decreased, the complexity in S gene networks increased, showing the characteristics of clustering and high connectivity. Indicates the strengthening mode in microbial interactions with the water content. Interestingly, the negative correlation of the network changed with the water content, and there was more competition among communities under the low water gradient and more cooperation under the high water gradient. Through the correlation between environmental factors and the network, nitrate (NO 3 À ) and soil available S (AS) constrained most S gene ecology networks. The key species involved in the S cycle were halophilic microorganisms. These results can enhance the understanding of soil S biogeochemical processes and contribute to the mitigation of desertification by improving soil conservation.

Rhizosphere is a powerful interface for interaction between soil, plants, and soil microorganisms. Little is known about the interactions between closely related species and their microbial communities in the desert. Using 16S rRNA and ITS high‐throughput sequencing methods, we studied the diversity of the rhizosphere and bulk soils microbial communities of the two species (Haloxylon ammodendron and Haloxylon persicum) at the edge of the Gurbantunggut Desert. Results showed that the diversity and composition of bacterial communities of these two species were significantly different, with bacteria and fungi explaining 53.54% and 35.40% of the total variation by principal coordinates analysis analysis. The Chao, Shannon, and Margalef index of the rhizosphere bacteria were significantly higher than those for the bulk bacteria(p < 0.05). The co‐occurrence network in rhizosphere soil were more complex than those in bulk soil, and bacteria were higher than that of fungi. Soil moisture, salinity, and nutrients significantly affected the diversity of the soil bacterial community (p < 0.05), but had no significant effects on the fungal community. The dissimilarity distance of bacterial community composition was significantly correlated with environmental distance (p < 0.05), and the most important environmental factor was available nutrients in the soil, which drove the soil microbial community composition and diversity. The composition and diversity of the bacteria in desert soil were affected by plant species and soil types, and differences among closely related species. These findings can enhance knowledge of the associations between closely related species and soil microorganisms, and contribute to the control of desertification.