A high throughput assay of lichenase activity with Congo red dye in plants

BACKGROUND: Since the beginning of the use of reporter proteins for expression analysis, a variety of approaches have been developed and proposed; both qualitative and quantitative. The lack of simple methods for direct observation of gene expression in living organisms makes it necessary to continue to propose new methods. In this work, we consider a method for the quantitative analysis of the expression of thermostable lichenase from Clostridium thermocellum used as a sensitive reporter protein. RESULTS: In this study, we report the design a high throughput fluorometric method for quantification of thermostable lichenase C. thermocellum using Congo red and further experimental verification of its relevance and efficiency in assessment of the functional role of regulatory sequences in the plant cell. CONCLUSIONS: The specific interaction between the dye Congo red and [Formula: see text] -d-glucans formed the background for designing a high-throughput fluorometric assay for quantification of C. thermocellum thermostable lichenase as a reporter protein for plants. This assay (i) makes it possible to precisely measure the amount of reporter protein in a plant sample; (ii) has shown a high sensitivity for quantification of thermostable lichenase; (iii) is more time- and cost-efficient as compared with the Somogyi–Nelson assay; and (iv) is to the least degree dependent on the presence of the tested buffer components as compared with the Somogyi–Nelson assay. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13007-021-00801-x.