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Low temperature-induced stress is a major environmental factor limiting the growth and development of plants. Alfalfa ( Medicago sativa L.) is a legume well known for its tolerance of extreme environments. In this study, we sought to experimentally investigate the role of rhizobium symbiosis in alfalfa’s performance under a low-temperature stress condition. To do this, alfalfa “Ladak + ” plants carrying active nodules (AN), inactive nodules (IN), or no nodules (NN) were exposed to an imposed low temperature stress and their survivorship calculated. The antioxidant defense responses, the accumulation of osmotic regulation substances, the cell membrane damage, and the expression of low temperature stress-related genes were determined in both the roots and the shoots of alfalfa plants. We found that more plants with AN survived than those with IN or NN under the same low temperature-stress condition. Greater activity of oxidation protective enzymes was observed in the AN and IN groups, conferring higher tolerance to low temperature in these plants. In addition, rhizobia nodulation also enhanced alfalfa’s ability to tolerate low temperature by altering the expression of regulatory and metabolism-associated genes, which resulted in the accumulation of soluble proteins and sugars in the nodulated plants. Taken together, the findings of this study indicate that rhizobium inoculation offers a practical way to promote the persistence and growth potential of alfalfa “Ladak + ” in cold areas.

Phototherapy has great potential to revolutionize conventional therapeutic modalities. However, most phototherapic strategies based on multicomponent therapeutic agents generally lack tumor-specificity, resulting in asynchronous therapy and superimposed side-effects. Severe heat...

Photodynamic sterilization is the most promising method to combat bacterial infection, especially multidrug-resistant bacterial infection. However, the absorption of conventional photosensitizers is mostly located in the UV−vis region, leading to limited penetration depth and poor therapeutic efficacy for deep-tissue bacterial infection. Besides, most of the photosensitizers are always in the activated state and lack bacteria-targeting ability, which inevitably causes severe nonspecific damage to normal tissues. Here, we show the design of a pH reversibly switchable near-infrared photosensitizer-based nanocapsule for precision bacteria-targeting fluorescence imaging-guided photodynamic sterilization. pH reversibly activatable asymmetric cyanine was synthesized as a bacteria-specific imaging unit and smart photosensitizer to realize precision imaging-guided targeting sterilization without side effects. An allicin mimic was introduced into the smart photosensitizer as the auxiliary bactericidal group to further enhance antibacterial efficiency. Meanwhile, amphipathic functionalized polyethylene glycol was employed to fabricate the nanocapsule by self-assembly to endow the charge-reversed intelligent targeting ability and prolong blood circulation. The developed switchable nanocapsule not only enables precision bacterial infection-targeted imaging without background fluorescence interference but also gives an efficient bactericidal effect with excellent specificity and negligible side effects, holding great potential for practical application.