Search

Seeds are important microbial vectors, and seed-associated pathogens can be introduced into a country through trade, resulting in yield and quality losses in agriculture. The aim of this study was to characterize the microbial communities associated with barley seeds, and based on which, to develop technical approaches to trace their geographical origins, and to inspect and identify quarantine pathogens. Our analysis defined the core microbiota of barley seed and revealed significant differences in the barley seed-associated microbial communities among different continents, suggesting a strong geographic specificity of the barley seed microbiota. By implementing a machine learning model, we achieved over 95% accuracy in tracing the origin of barley seeds. Furthermore, the analysis of co-occurrence and exclusion patterns provided important insights into the identification of candidate biocontrol agents or microbial inoculants that could be useful in improving barley yield and quality. A core pathogen database was developed, and a procedure for inspecting potential quarantine species associated with barley seed was established. These approaches proved effective in detecting four fungal and three bacterial quarantine species for the first time in the port of China. This study not only characterized the core microbiota of barley seeds but also provided practical approaches for tracing the regional origin of barley and identifying potential quarantine pathogens. [Display omitted] • We characterized the barley-seed associated bacterial and fungal communities of Oceania, North America, and Europe. • Our analysis defined the core microbiota of barley seed and revealed significant differences among different continents, suggesting a strong geographic specificity of the barley seed microbiota. • We could accurately predict the original countries of imported barley grains within the RF prediction model, with an accuracy greater than 95%. • We constructed a barley-related quarantine pathogens database. Based on this database, some important pathogens were intercepted through metabarcoding sequencing. [ABSTRACT FROM AUTHOR]

Abstract: Since transglutaminase (TGase) have been widely used in industry, mass production of the enzyme is especially necessary. The mature TGase gene from Streptomyces fradiae was cloned into pET21a and overexpressed in Escherichia coli BL21(DE3). The recombinant TGase was formed as inclusion bodies, and its content was as high as 55% of the total protein content. The insoluble fractions were separated from cellular debris by centrifugation and solubilized with 8M urea. With an on-column refolding procedure based on cation SP Fast Flow chromatography with dual-gradient, the active TGase protein was recovered efficiently from inclusion bodies. The final purified product was 95% pure detected by SDS–PAGE. Under appropriate experimental conditions, the protein yield and specific activity of the TGase were up to 53% and 21U/mg, respectively. Furthermore, the refolded recombinant protein demonstrated nearly identical ability to polymerized BSA compared with that of native TGase. One hundred and five milligrams of refolded TGase protein was obtained from 3.2g wet weight cells in the 400ml cell culture. [Copyright &y& Elsevier]