A Root Tip-Specific Expressing Anthocyanin Marker for Direct Identification of Transgenic Tissues by the Naked Eye in Symbiotic Studies.

Yiting Ruan,Jeremy D Murray,Ke Chen,Yangyang Su,Suyu Jiang,Ping Xu

doi:10.3390/plants10030605

Abstract

The Agrobacterium rhizogenes hairy root transformation system is widely used in symbiotic studies of model legumes. It typically relies on fluorescent reporters, such as DsRed, for identification of transgenic roots. The MtLAP1 transcription factor has been utilized as a reporter system in Medicago truncatula based on production of anthocyanin pigment. Here, we describe a version of this reporter driven by a root-cap specific promoter for direct observation of anthocyanin accumulation in root tips, which allows the identification of transgenic hairy roots by the naked eye. Results from our analysis suggest that the reporter had no significant effects on nodulation of M. truncatula. This approach, by virtue of its strong and specific expression in root cap cells, greatly reduces false positives and false negatives, and its use of an easily scored visible pigment should allow greater versatility and efficiency in root biology studies.

Highlights

The model legume species Medicago truncatula has been used extensively to study interactions with nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi [1,2,3]
The resulted vector was named pMtRC-MtLAP1 (Figure S1b), which was transformed into A. rhizogenes strain ARqua1 for generating transgenic hairy roots of M. truncatula cv
We investigated whether anthocyanins produced exclusively in the root tip could be used as a screening marker for M. truncatula hairy root transformation

Summary

Introduction

The model legume species Medicago truncatula has been used extensively to study interactions with nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi [1,2,3]. Both interactions occur within plant roots, and M. truncatula has been used for studies on root biology, such as in hormone regulation, nutrient response, water stress, root architecture, etc. Observation of fluorescent markers needs a specially equipped microscope, and there may be problems with background autofluorescence depending on the plants or tissues being studied and fluorescent proteins being used. Another issue is that use of a fluorescent reporter protein often precludes its use in protein fusions, and so reduces the options available to the researcher

Methods

Results

Conclusion