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As a type of nanomaterials with enzyme-mimetic catalytic properties, nanozymes have attracted wide concern in biological detection. H 2 O 2 was the characteristic product of diverse biological reactions, and the quantitative analysis for H 2 O 2 was an important way to detect disease biomarkers, such as acetylcholine, cholesterol, uric acid and glucose. Therefore, there is of great significance for developing a simple and sensitive nanozyme to detect H 2 O 2 and disease biomarkers by combining with corresponding enzyme. In this work, Fe-TCPP MOFs were successfully prepared by the coordination between iron ions and porphyrin ligands (TCPP). In addition, the peroxidase (POD) activity of Fe-TCPP was proved, in detail, Fe-TCPP could catalyze H 2 O 2 to produce ·OH. Herein, glucose oxidase (GOx) was chosen as the model to build cascade reaction by combining Fe-TCPP to detect glucose. The results indicated glucose could be detected by this cascade system selectively and sensitively, and the limit of detection of glucose was achieved to 0.12 μM. Furthermore, a portable hydrogel (Fe-TCPP@GEL) was further established, which encapsulated Fe-TCPP MOFs, GOx and TMB in one system. This functional hydrogel could be applied for colorimetric detection of glucose by coupling with a smartphone easily. Nanozyme of Fe-TCPP and corresponding hydrogel were constructed, and they were further developed to detect glucose. [Display omitted] • A simple and efficient nanozyme for the detection of glucose is reported. • A universal hydrogel system containing both natural enzymes and nanozymes is developed. • Fe-TCPP@GEL could carry out the quantitative analysis of glucose by coupling with a smartphone easily. [ABSTRACT FROM AUTHOR]

Microbial antagonists and their bioactive metabolites provide one of the best alternatives to chemical pesticides to control crop disease for sustainable agriculture and global food security. The rice endophyte Streptomyces hygroscopicus OsiSh-2, with remarkable antagonistic activity towards the rice blast fungus Magnaporthe oryzae , was reported in our previous study. The present study deciphered the possible direct interaction mode of OsiSh-2 against M. oryzae. An in vitro antibiotic assay for OsiSh-2 culture filtrate revealed strong suppression of mycelial growth, conidial germination and appressorial formation of M. oryzae. Meanwhile, severe morphological and internal abnormalities in M. oryzae hyphae were observed under a scanning electron microscope and transmission electron microscope. Foliar treatment of rice seedlings by OsiSh-2 culture filtrate in the greenhouse and in the field showed 23.5% and 28.3% disease reduction, respectively. Correspondingly, OsiSh-2 culture filtrate could induce disorganized chitin deposition in the cell wall and lowered ergosterol content in the cell membrane of M. oryzae. Additionally, cell wall integrity pathway activation, large cell electrolytes release, reactive oxygen species accumulation and tricarboxylic acid cycle-related enzyme activity changes were found in M. oryzae. All these results suggested that the direct antagonistic activity of OsiSh-2 against M. oryzae may be attributed to damaging the integrity of the cell wall and membrane and disrupting mitochondrial function in the pathogen. Unlabelled Image • Endophytic Streptomyces suppressed the rice blast disease efficiently in the field and in the greenhouse. • Endophytic Streptomyces inhibited M. oryzae growth, conidial germination and appressorial formation. • Endophytic Streptomyces damaged the integrity of M. oryzae cell wall and membrane. • Endophytic Streptomyces induced fungal ROS burst and affected mitochondrial dehydrogenase activities in M. oryzae. [ABSTRACT FROM AUTHOR]