# PtBGL: a cost-effective alternative to GUS reporter with applications in plant imprint dyeing

## TL;DR

PtBGL is a low-cost alternative to the GUS reporter system for tracking gene expression in plants and can be used for plant-based fabric imprinting.

## Contribution

PtBGL, derived from Persicaria tinctoria, offers a cost-effective and visible reporter system with minimal background activity in multiple plant species.

## Key findings

- PtBGL produces a visible blue pigment when expressed in Arabidopsis and Nicotiana.
- Endogenous β-glucosidase background activity was absent in 13 out of 14 tested plant species.
- PtBGL enables cost-effective transgenic screening and gene expression analysis.

## Abstract

Reporter gene systems are essential tools for monitoring gene expression and transformation efficiency in plant research. The widely used GUS system provides strong, stable, and well-localized signals but requires expensive substrates. Here, we present an alternative based on Persicaria tinctoria β-glucosidase (PtBGL) and its natural substrate indican, which is a low-cost indoxyl glucoside extractable from heat-treated indigo plants. When expressed in Arabidopsis thaliana and Nicotiana benthamiana, PtBGL localizes to plastids and converts indican into a blue indigo pigment visible to the naked eye. Comparative assays in 13 of the 14 tested plant species revealed no detectable background activity from endogenous β-glucosidases at the examined developmental stage. The PtBGL and indican system enables cost-effective transgenic screening, gene expression analysis, and practical applications such as plant-based fabric imprinting.