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In desert ecosystems, the desertification process is characterized by increasing attenuation of plant productivity and deterioration of soil habitats, leading to enhanced environmental stress gradients for soil microbiomes. Despite the significance of microbial communities for multifunctionality in terrestrial ecosystems, the feedback dynamics of microbiomes and their contributions to maintaining deep soil (20–100 cm) multifunctionality as desertification progresses have yet to be evaluated. Here, we used three sites with different desertification stages and investigated the variation trends of microbiomes in soil profiles (0–100 cm) and their contributions to regulating multifunctionality. The multifunctionality did not exhibit a significant difference between superficial (0–20 cm) and deep soils and slightly decreased as depth increased throughout the entire profile. Results from alpha‐ and beta‐diversity analysis of soil microbiomes suggested that bacterial communities received on average more positive and progressive feedback from desertification development than fungal and archaeal communities. Particular microbial clades rather than total microbial diversity best predict and explain the vertical profile variation in soil multifunctionality in desert ecosystems. Microbial clades within Acidobacteria could be targeted for future soil‐focussed, bottom‐up desertification control studies.

In desert ecosystems, the desertification process is characterized by increasing attenuation of plant productivity and deterioration of soil habitats, leading to enhanced environmental stress gradients for soil microbiomes. Despite the significance of microbial communities for multifunctionality in terrestrial ecosystems, the feedback dynamics of microbiomes and their contributions to maintaining subsurface soil multifunctionality as desertification progresses have yet to be evaluated. Here, we used three sites with different desertification stages and investigated the variation trends of microbiomes in soil profiles (0-100 cm) and their contributions to regulating multifunctionality. We first confirmed that multifunctionality did not exhibit a significant difference between superficial soils (0-20 cm) and deep soils (20-100 cm) and slightly decreased as soil depth increased throughout the entire profile. Desertification progression drove distinct variation trends of microbiomes in vertical soil profiles. Soil bacterial communities received on average more positive and progressive feedback from desertification development than fungal and archaeal communities, characterized by significant variation in bacterial alpha- and beta-diversity and slight variation in fungal and archaeal alpha- and beta-diversity. The most abundant phyla in the microbiomes did not vary between the superficial and deep soils at any desertification stage. Significant declines in microbial clades within Acidobacteria are an important feature as desertification proceeds. Particular microbial taxa rather than total microbial diversity best predict and explain the vertical profile variation in soil multifunctionality in desert ecosystems. Our results highlight the significance of microbial community composition in subsurface soils for regulating multifunctionality in desert ecosystems.

The synthesis of ROS-responsive polymers has attracted much attentions in recent years. Herein, we report a series of amphiphilic methoxy poly(ethylene glycol)-b-poly(carbonate-selenide)s (mPEG45-b-poly(MSe)m, m = 12, 24, 36, 48, 60) by introducing selenide groups onto the backbone via one-pot lipase-catalyzed ring-opening polymerization (ROP), the synthesized amphiphilic polymers with enhanced ROS-responsiveness can self-assemble to form nanoparticles. Nuclear Magnetic Resonance (NMR), Gel Permeation Chromatography (GPC) and Fourier Transform Infrared (FTIR) are employed to confirm the structure of the polymers. Besides, the oxidation process of mPEG45-b-poly(MSe)m nanoparticles is also clarified. Ultraviolet–visible Spectrophotometer (UV–Vis), Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) are further utilized to demonstrate the turbidity, morphology and size changes under oxidization, proving that the selenide groups endow the mPEG45-b-poly(MSe)m nanoparticles with enhanced ROS-response properties. Therefore, the above studies highlight the synthesized ROS-responsive polymers and provided a potential material for further applications.

The integration of hypoxia-activated chemotherapy with photodynamic therapy (PDT) has newly become a potent strategy for tumor treatment. Herein, a reactive oxygen species (ROS)-responsive drug carriers (PS@AQ4N/mPEG-b-PSe NPs) are fabricated based on the amphiphilic selenium-containing methoxy poly(ethylene glycol)-polycarbonate (mPEG-b-PSe), the hydrophobic photosensitizer (PS), and hypoxia-activated prodrug Banoxantrone (AQ4N). The obtained nanoparticles are spherical with an average diameter of 100 nm as characterized by transmission electron microscope (TEM) and dynamic laser scattering (DLS) respectively. The encapsulation efficiency of the PS and AQ4N reaches 92.83% and 51.04% at different conditions, respectively, by UV-vis spectrophotometer. It is found that the drug release is accelerated due to the good ROS responsiveness of mPEG-b-PSe and the cumulative release of AQ4N is up to 89% within 30 h. The cell test demonstrates that the nanoparticles dissociate when triggered by the ROS stimuli in the cancer cells, thus the PS is exposed to more oxygen and the ROS generation efficiency is enhanced accordingly. The consumption of oxygen during PDT leads to the increased tumor hypoxia, and subsequently activates AQ4N into cytotoxic counterpart to inhibit tumor growth. Therefore, the synergistic therapeutic efficacy demonstrates this drug delivery has great potential for antitumor therapy.

With ongoing global climate change and human activities, increasing desertification plays a predominant role in increasing soil nutrient losses. Soil nitrogen (N) is the essential limiting nutrient supporting plant growth and evaluating soil nutrient content, especially in desert ecosystems. N microbial processes will ultimately restore and maintain the balance in the soil N cycle, but the damage caused by desertification to soil N functional microorganisms associated with N supply, transformation, and loss is poorly understood. We examined changes in soil N and N functional gene (NFG) abundances within vertical profiles (i.e., soil depths of 0–100 cm) throughout the desertification process. We found that the abundance of N functional genes (NFGs) (except the N-fixation gene) decreased during the desertification process, almost all NFGs were attenuated along the vertical profiles, and available phosphorus (AP), soil water content (SWC) and pH were the best explanatory variables. The sums of (AOA + AOB) (associated with available N transformation) and (nirK + nirS + qnorB + nosZ) (associated with N loss) significantly decreased as desertification progressed, leading to decreased N transformation and loss potential. The (nifH + chiA) associated with available N supply increased along the desertification process gradient, suggesting enhanced potential for the acquisition available N. The increased ratio of (nifH + chiA + AOA + AOB)/(nirK + nirS + qnorB + nosZ) (associated with available N storage) collaboratively contributed to enhanced available N storage potential throughout the desertification process. Our results lay the foundation for better understanding the distinct responses of NFGs to desertification and the process through which they ultimately regulate available N storage in the degraded soils of desert ecosystems.