Escherichia colimazEF Toxin-Antitoxin System as a Tool to Target Cell Ablation in Plants

Abstract

Background/Aims: The Escherichia coli MazF is an endoribonuclease that cleaves mRNA at ACA sequences, thereby triggering inhibition of protein synthesis. The aim of this study is to evaluate the efficiency of the mazEF toxin-antitoxin system in plants to develop biotechnological tools for targeted cell ablation. Methods: A double transformation strategy, combining expression of the mazE antitoxin gene under the control of the CaMV 35S promoter, reported to drive expression in all plant cells except within the tapetum, together with the expression of the mazF gene under the control of the TA29 tapetum-specific promoter in transgenic tobacco, was applied. Results: No transgenic TA29-mazF line could be regenerated, suggesting that the TA29 promoter is not strictly tapetum specific and that MazF is toxic for plant cells. The regenerated 35S-mazE/TA29-mazF double-transformed lines gave a unique phenotype where the tapetal cell layer was necrosed resulting in the absence of pollen. Conclusion: These results show that the E. colimazEF system can be used to induce death of specific plant cell types and can provide a new tool to plant cell ablation.

Biology and evolution of bacterial toxin–antitoxin systems

“…For example, the GeneGuard system encodes the toxin on the plasmid and the antitoxin on the chromosome, therefore coupling the plasmid to a specific host 228 . Other technologies were developed in plants to control the spread of transfer DNa from genetically modified agrobacteria or the development of specific plant tissues, notably tissue essential for pollen development 227,229 . mimicking a CRISPR RNA that recruits a Cas protein acting as a transcriptional repressor 29,52 (Fig.…”

MqsR toxin as a biotechnological tool for plant pathogen bacterial control

“…S5). Curiously, phytotoxicity was observed in Arabidopsis thaliana expressing the yoeB from Streptococcus pneumoniae 44 and Nicotiana tabacum expressing mazF from Escherichia coli 45 . We believe that these differences are related to the nature of the toxins because tobacco plants expressing MqsR also showed no alterations in phenotype, similar to the citrus plants (Figure S5).…”

Bacterial Toxin-Antitoxin Systems’ Cross-Interactions—Implications for Practical Use in Medicine and Biotechnology

“…In parallel, the MazE antitoxin was expressed in the other plant tissues to protect them from the toxin’s activity. In this way, researchers were able to obtain male sterility in tobacco plants [ 216 ].…”