TAL Effectors Drive Transcription Bidirectionally in Plants

Area of Science:

• Molecular Biology
• Plant Pathology
• Genetics

Background:

• TAL effectors are DNA-binding proteins from Xanthomonas bacteria that regulate plant gene expression.
• Previously, effector binding elements (EBEs) were only identified on the forward strand of target promoters.
• The modular DNA recognition of TAL effectors makes them valuable tools for gene editing.

Purpose of the Study:

• To investigate the ability of TAL effectors to drive transcription from EBEs on both DNA strands.
• To explore novel modes of action for TAL effectors in plant systems.
• To expand the understanding of TAL effector targeting and applications.

Main Methods:

• Demonstrated TAL effector-driven transcription from EBEs on both forward and reverse DNA strands.
• Utilized a native TAL effector from Xanthomonas oryzae pv. oryzicola.
• Employed reporter gene assays with promoter constructs containing EBEs on each strand.

Main Results:

• TAL effectors can activate plant transcription from effector binding elements (EBEs) located on either DNA strand and in both transcriptional directions.
• A native TAL effector activated expression from EBEs on both strands of a target promoter.
• Activity at the reverse-strand EBE potentiated transcription driven by the forward-strand EBE.

Conclusions:

• TAL effectors exhibit novel modes of action, driving transcription from both DNA strands.
• New potential targets for TAL effectors in plant-pathogen interactions may exist.
• The findings broaden the scope for TAL effector applications in gene editing and fundamental plant transcription research.